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Lesluyes, Tom, Jean-Yves Blay, Patrick Schoffski, et al. "Expression and prognostic significance of PDGF ligands (A, B, C, and D) and PDGFR (A, B, and L) in soft-tissue sarcomas and GIST." Journal of Clinical Oncology 35, no. 15_suppl (2017): 11067. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.11067.
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11067 Background: Sarcomas are a variety of rare connective tissue cancers. Doxorubicin and olaratumab (Ab against PDGFRA) improved survival in a recent Phase 1/2 study. Besides PDGFRA mutated gastrointestinal stroma tumor (GIST) and dermatofibrosarcoma protuberans, the role of PDGFR and the according ligands in the biology of sarcoma remain unclear. Methods: The expression levels of PDGF (A,B,C,D) and PDGFRs (A,B,L) were studied in a series of 255 sarcoma pts in localized phase using the Agilent 014850 platform. Data are available online (http://atg-sarc.sarcomabcb.org). Histologies were GIST (n = 60), myxoid liposarcoma (MLPS, n = 50), synovial sarcoma (SyS, n = 58), and sarcoma with complex genomics (SCG, n = 87). Expression levels were analyzed and tested for prognostic values for metastasis free survival (MFS) in uni- and multivariate analysis using SPSS 19.0. Results: Expression levels (ELs) of PDGFs and PDGFRs varied across histotypes: PDGFA levels were highest in SyS and lowest in MLPS (p < 0.0001). PDGFB and C levels were lower in GIST (p < 0.0001), while PDGFD ELs were similar across histological subtypes. PDGFRA ELs were highest in MLPS, while PDGFRB & L ELs were lowest in GIST and SyS (p < 0.0001 all). Complex patterns of correlation of expression between ligands and receptors were observed in each individual subtypes. PDGFA ELs above median were associated with a marginally higher risk of metastasis . Conversely, PDGFD ELs above median was associated with a reduced risk of metastasis in the whole cohort (p = 0.02). The ELs of the 3 receptors were not correlated to MFS. In multivariate analysis using Cox model on the non-GIST sarcoma cohort (histology, grade, depth, with size, PDGFA, PDGFD as continuous variables): histology, size, grade and PDGFA ELs were independent adverse prognostic factors (PF), while PDGFD ELs was a favorable PF for MFS. In the GIST cohort, testing AFIP score, PDGFA & D ELs as continuous variable, PDGFD ELs was also an independent favorable PF for MFS, in addition to AFIP score. Conclusions: The expression of PDGFs and the according receptors varies across sarcoma histological subtypes. PDGFA and D expression levels correlate independently to the risk of metastatic relapse.
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Lin, Li-Han, Jiun-Sheng Lin, Cheng-Chieh Yang, Hui-Wen Cheng, Kuo-Wei Chang, and Chung-Ji Liu. "Overexpression of Platelet-Derived Growth Factor and Its Receptor Are Correlated with Oral Tumorigenesis and Poor Prognosis in Oral Squamous Cell Carcinoma." International Journal of Molecular Sciences 21, no. 7 (2020): 2360. http://dx.doi.org/10.3390/ijms21072360.
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Oral squamous cell carcinoma (OSCC) is a cancerous disease with poor prognosis. According to the statistics, the 5-year survival rate has not improved significantly over the past 20 years. The platelet-derived growth factor (PDGF) and its signaling pathway is a key regulator of angiogenesis and tumorigenesis. High level of PDGF and its receptor (PDGFR) have been reported in several types of malignancies. In this study, we investigated the relationship of the molecular expression levels of PDGF and PDGFR with clinicopathological parameters in OSCC. To this end, we measured the mRNA and protein levels of PDGF and PDGFR by real-time quantitative PCR (qRT-PCR), immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA), respectively. We found positive correlations of the mRNA levels of PDGFA, PDGFB, and PDGFRB with lymph node metastasis and poor overall survival (OS). High expression of PDGF, PDGFRA, and PDGFRB were remarkably associated with lymph node metastasis and poor OS, as determined by immunohistochemistry. Preoperative serum levels of PDGF-AA and PDGF-BB had a positive correlation with preoperative platelet count. Elevated serum levels of PDGF-AA. PDGF-BB, and platelet count correlated with lymph node metastasis and an unfavorable outcome. In multivariate Cox regression analysis, PDGFA mRNA, PDGFB mRNA, PDGFRB mRNA, PDGF immunoexpression, PDGFRB immunoexpression, serum PDGF-AA, serum PDGF-BB, and platelet count emerged as significant independent prognostic factors for OS. In vitro, we found that elevated PDGF promotes colony formation, migration, and invasiveness of SAS and OECM-1 cancer cell lines. Our results suggest that the expression level of serum PDGF has the potential to become a useful diagnostic marker for the prognosis of OSCC. In addition, PDGFR should be considered as a potential therapeutic target for OSCC. Furthermore, research should be undertaken to elucidate the role of PDGF and PDGFR regarding the behavior of tumor cells in OSCC.
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Ball, Stephen G., Christopher Bayley, C. Adrian Shuttleworth, and Cay M. Kielty. "Neuropilin-1 regulates platelet-derived growth factor receptor signalling in mesenchymal stem cells." Biochemical Journal 427, no. 1 (2010): 29–40. http://dx.doi.org/10.1042/bj20091512.
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Using human MSCs (mesenchymal stem cells) lacking VEGF (vascular endothelial growth factor) receptors, we show that the pro-angiogenic receptor neuropilin-1 associates with phosphorylated PDGFRs [PDGF (platelet-derived growth factor) receptors], thereby regulating cell signalling, migration, proliferation and network assembly. Neuropilin-1 co-immunoprecipitated and co-localized with phosphorylated PDGFRs in the presence of growth factors. Neuropilin-1 knockdown blocked PDGF-AA-induced PDGFRα phosphorylation and migration, reduced PDGF-BB-induced PDGFRβ activation and migration, blocked VEGF-A activation of both PDGFRs, and attenuated proliferation. Neuropilin-1 prominently co-localized with both PDGFRs within MSC networks assembled in Matrigel™ and in the chorioallantoic membrane vasculature microenvironment, and its knockdown grossly disrupted network assembly and decreased PDGFR signalling. Thus neuropilin-1 regulates MSCs by forming ligand-specific receptor complexes that direct PDGFR signalling, especially the PDGFRα homodimer. This receptor cross-talk may control the mobilization of MSCs in neovascularization and tissue remodelling.
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Gueller, Saskia, Sigal Gery, and H. Phillip Koeffler. "Adaptor Protein Lnk Binds to PDGFRA, PDGFRB and FIP1L1-PDGFRA, but Not to the TEL-PDGFRB Fusion Protein." Blood 110, no. 11 (2007): 2213. http://dx.doi.org/10.1182/blood.v110.11.2213.2213.
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Abstract PDGFRA and PDGFRB (platelet derived growth factor receptors alpha and beta) are frequently expressed on malignant hematopoietic cells and regulate various cellular responses such as development, proliferation, differentiation, cell survival and cellular transformation. Stimulation by either autocrine loops or constitutional activation by chromosomal translocation (i.e. chronic myelomonocytic leukemia [CMML, TEL-PDGFRB] or chronic eosinophilic leukemia [CEL, FIP1L1-PDGFRA]) makes them important factors in development of hematopoietic disorders. Normally, interaction with the ligand PDGF, induces dimerization of two distinct receptor subunits, resulting in activation of the intracellular tyrosine kinase domain and phosphorylation of tyrosine residues, thereby creating binding sites for several molecules containing Src homology 2 (SH2) domains. We hypothesized that one such protein may be the adaptor Lnk, a negative regulator of several hematopoietic cytokine receptors including MPL, EpoR and c-Kit. Lnk belongs to a family of proteins sharing several structural motifs including a SH2 domain, a pleckstrin homology domain (PH) and a dimerization domain (DD). The SH2 domain is known to be essential for its inhibitory effect which can be abolished by the point mutation R392E. We investigated the ability of Lnk to bind to PDGFRA, PDGFRB, FIP1L1-PDGFRA and TEL-PDGFRB. To determine the domain of Lnk that is responsible for the binding, we constructed a series of V5-tagged Lnk mutants including: a mutation in the SH2 domain (R392E); deletion of the SH2 domain; deletion of the PH and SH2 domains and a construct only containing the DD domain. 293T cells were co-transfected with cDNAs encoding either PDGFRA, PDGFRB or one of the translocation products and either wild-type or mutant Lnk. Whole cell lysates were used to perform immunoprecipitation with either V5-tag or PDGFR antibodies. Binding of Lnk and PDGFR was detected by Western blot probed with PDGFR or V5-tag antibodies. NIH3T3 cells were transfected either with empty vector or Lnk cDNA, transfectants were selected for 5 days with G418, serum starved for 16 hours and induced with PDGF for 10 minutes. Phosphorylation of downstream targets of PDGFRA and PDGFRB was detected by Western blot. Our data showed that Lnk bound to PDGFRA and PDGFRB only after exposure of the cells to PDGF and to the FIP1L1-PDGFRA fusion protein independent of PDGF exposure. Mutation or deletion of the Lnk SH2 domain abolished binding completely in PDGFRA and FIP1L1-PDGFRA, but just partly in PDGFRB. Expression of Lnk in NIH3T3 cells inhibited phosphorylation of ERK after treatment with PDGF. In other experiments, we determined that Lnk bound the juxtamembrane region of this class of receptors. Interestingly, the TEL-PDGFRB fusion protein was unable to bind Lnk, although its breakpoint in PDGFRB is distal to the juxtamembrane domain and the whole intracellular region of PDGFRB is included in the fusion protein. Further exploration of the mechanisms by which Lnk affects wild-type or PDGFR fusion product will provide insight into the molecular pathophysiology of myeloid disorders and could help develop new treatments.
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Kilvaer, Thomas Karsten, Andrej Valkov, Sveinung W. Sorbye, et al. "Platelet-Derived Growth Factors in Non-GIST Soft-Tissue Sarcomas Identify a Subgroup of Patients with Wide Resection Margins and Poor Disease-Specific Survival." Sarcoma 2010 (2010): 1–10. http://dx.doi.org/10.1155/2010/751304.
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Background. Optimal treatment of nongastrointestinal stromal tumor soft-tissue sarcomas (non-GIST STSs) is resection with wide margins. This study investigates the prognostic impact of the angiogenesis-associated platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) in non-GIST STS patients with wide and nonwide resection margins.Method. Tumor samples and clinical data from 249 patients with non-GIST STS were obtained, and tissue microarrays were constructed for each specimen. Immunohistochemistry was used to evaluate the expression of PDGF-A, -B, -C, and -D and PDGFR-αand -β.Results. In the multivariate analysis of patients with wide resection margins, high expression of PDGF-B (, HR = 2.954, and 95% CI = 1.255–6.956) and the coexpression of PDGF-B and PDGFR-α(overall; , high-low/low-high; , HR = 2.678, 95% CI = 0.996–7.200, high/high; , HR = 3.930, 95% CI = 1.542–10.015) were independent negative prognostic markers for disease-specific survival.Conclusion.PDGF-B and the coexpression of PDGF-B and PDGFR-αare strong and independent prognostic factors in non-GIST STSs with wide resection margins.
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Rogers, Madison A., and Katherine A. Fantauzzo. "The emerging complexity of PDGFRs: activation, internalization and signal attenuation." Biochemical Society Transactions 48, no. 3 (2020): 1167–76. http://dx.doi.org/10.1042/bst20200004.
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The platelet-derived growth factor receptor (PDGFR) family of receptor tyrosine kinases allows cells to communicate with the environment to regulate diverse cellular activities. Here, we highlight recent data investigating the structural makeup of individual PDGFRs upon activation, revealing the importance of the whole receptor in the propagation of extracellular ligand binding and dimerization. Furthermore, we review ongoing research demonstrating the significance of receptor internalization and signal attenuation in the regulation of PDGFR activity. Interactions with internalization machinery, signaling from endosomes, receptor degradation and receptor recycling are physiological means by which cells fine-tune PDGFR responses to growth factor stimulation. In this review, we discuss the biophysical, structural, in silico and biochemical data that have provided evidence for these mechanisms. We further highlight the commonalities and differences between PDGFRα and PDGFRβ signaling, revealing critical gaps in knowledge. In total, this review provides a conclusive summary on the state of the PDGFR field and underscores the need for novel techniques to fully elucidate the mechanisms of PDGFR activation, internalization and signal attenuation.
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Tsao, Anne S., Nusrat Harun, Junya Fujimoto, et al. "Elevated PDGFRB gene copy number gain as prognostic in resected malignant pleural mesothelioma." Journal of Clinical Oncology 30, no. 15_suppl (2012): 7078. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.7078.
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7078 Background: PDGF/PDGFR pathway has been implicated in malignant pleural mesothelioma (MPM) carcinogenesis. We sought to evaluate the incidence of PDGFRB gene copy number gain (CNG) and PDGFR pathway protein expression by immunohistochemistry (IHC) in the tumor cell cytoplasm, membrane, nucleus, and stroma, and correlate it to patient clinical outcome. Methods: 88 archived tumor blocks from resected MPM with full clinical information were used to perform the analyses. IHC biomarkers for PDGFRα,β and p-PDGFRβ, and fluorescence in situ hybridization were performed for analysis of PDGFRB gene CNG. Spearman’s rank correlation, Wilcoxon rank-sum test or Kruskal-Wallis test, BLiP plots, and Kaplan-Meier method were used to assess the biomarkers and their correlation to clinical outcome. Results: There were several correlations identified between the IHC biomarkers; however, none associated with patient demographics or histology subtype, with the exception of high cytoplasmic PDGFRα occurring in patients with no prior known asbestos exposure (p=0.029). In the CNG analysis, PDGFRB gene CNG in > 10% of tumor cells had lower cytoplasmic p-PDGFRβ (p=0.029), while PDGFRB gene CNG in > 40% of tumor cells had a higher cytoplasmic PDGFRβ (p=0.04). PDGFRB gene CNG status did not associate with patient demographics or tumor characteristics. Patients with PDGFRB CNG > 40% of tumor cells had an improved relapse-free survival (RFS) [HR 0.25 (95% CI 0.09, 0.72), p=0.0096]. In the patients with PDGFRB CNG > 40% of cells, the addition of chemotherapy appeared to also improve RFS (p=0.017). In the multi-covariate analyses for RFS, there was no association with any IHC biomarker. In the overall survival (OS) analysis, having PDGFRB gene CNG > 40% of tumor cells correlated with an improved OS [HR 0.32 (95% CI 0.11, 0.89), p=0.029] and the addition of peri-operative chemotherapy led to a trend towards improved OS (p=0.089). Conclusions: PDGFRB CNG > 40% of tumor cells is a potential prognostic biomarker in surgically resected MPM tumors. Adding chemotherapy to patients with PDGFRB CNG > 40% of cells improved RFS and led to a trend towards improved OS. Future validation of this biomarker in prospective trials is needed.
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Fitter, Stephen, Kate Vandyke, Stan Gronthos, and Andrew C. W. Zannettino. "Suppression of PDGF-induced PI3 kinase activity by imatinib promotes adipogenesis and adiponectin secretion." Journal of Molecular Endocrinology 48, no. 3 (2012): 229–40. http://dx.doi.org/10.1530/jme-12-0003.
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Improved glucose and lipid metabolism is a unique side effect of imatinib therapy in some chronic myeloid leukaemia (CML) patients. We recently reported that plasma levels of adiponectin, an important regulator of insulin sensitivity, are elevated following imatinib therapy in CML patients, which could account for these improved metabolic outcomes. Adiponectin is secreted exclusively from adipocytes, suggesting that imatinib modulates adiponectin levels directly, by transcriptional upregulation of adiponectin in pre-existing adipocytes, and/or indirectly, by stimulating adipogenesis. In this report, we have demonstrated that imatinib promotes adipogenic differentiation of human mesenchymal stromal cells (MSCs), which in turn secrete high-molecular-weight adiponectin. Conversely, imatinib does not stimulate adiponectin secretion from mature adipocytes. We hypothesise that inhibition of PDGFRα (PDGFRA) and PDGFRβ (PDGFRB) is the mechanism by which imatinib promotes adipogenesis. Supporting this, functional blocking antibodies to PDGFR promote adipogenesis and adiponectin secretion in MSC cultures. We have shown that imatinib is a potent inhibitor of PDGF-induced PI3 kinase activation and, using a PI3 kinase p110α-specific inhibitor (PIK-75), we have demonstrated that suppression of this pathway recapitulates the effects of imatinib on MSC differentiation. Furthermore, using mitogens that activate the PI3 kinase pathway, or MSCs expressing constitutively activated Akt, we have shown that activation of the PI3 kinase pathway negates the pro-adipogenic effects of imatinib. Taken together, our results suggest that imatinib increases plasma adiponectin levels by promoting adipogenesis through the suppression of PI3 kinase signalling downstream of PDGFR.
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Kanaan, Rana, and Charlie Strange. "Use of multitarget tyrosine kinase inhibitors to attenuate platelet-derived growth factor signalling in lung disease." European Respiratory Review 26, no. 146 (2017): 170061. http://dx.doi.org/10.1183/16000617.0061-2017.
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Platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) play a fundamental role in the embryonic development of the lung. Aberrant PDGF signalling has been documented convincingly in a large variety of pulmonary diseases, including idiopathic pulmonary arterial hypertension, lung cancer and lung fibrosis. Targeting PDGF signalling has been proven to be effective in these diseases. In clinical practice, the most effective way to block PDGF signalling is to inhibit the activity of the intracellular PDGFR kinases. Although the mechanism of action of such drugs is not specific for PDGF signalling, the medications have a broad therapeutic index that allows clinical use. The safety profile and therapeutic opportunities of these and future medications that target PDGFs and PDGFRs are reviewed.
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Ren, Wenying, Stephanie W. Watts та Barry L. Fanburg. "Serotonin transporter interacts with the PDGFβ receptor in PDGF-BB-induced signaling and mitogenesis in pulmonary artery smooth muscle cells". American Journal of Physiology-Lung Cellular and Molecular Physiology 300, № 3 (2011): L486—L497. http://dx.doi.org/10.1152/ajplung.00237.2010.
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The serotonin transporter (SERT) and the platelet-derived growth factor receptor (PDGFR) have been implicated in both clinical and experimental pulmonary hypertension (PH) and the facilitation of pulmonary artery smooth muscle cell (PASMC) growth. To gain a better understanding of the possible relationship of these two cell surface molecules we have explored interactions between SERT and PDGFR. We have previously demonstrated that SERT transactivates PDGFRβ in serotonin-stimulated PASMC proliferation. We now provide evidence for a role for SERT in PDGF-BB signaling and PASMC proliferation by using pharmacological inhibitors, genetic ablation, and construct overexpression of SERT. The results show that four tested SERT blockers dose dependently inhibit PDGF-stimulated human and bovine PASMC proliferation with comparable efficacy to that of PDGFR inhibitors, whereas 5-HT1B or 5-HT2A receptor inhibitors had no effect. Combinations of the SERT and PDGFR inhibitors led to synergistic/additive inhibition. Similarly, PDGF-induced PASMC proliferation was attenuated by small interfering RNA downregulation of SERT. Inhibition of SERT in PASMCs attenuated PDGF-induced phosphorylation of PDGFRβ, Akt, and p38 but not Erk. Overexpression of SERT in HEK293 cells led to enhanced Akt phosphorylation by PDGF, which was blunted by a SERT PDZ motif mutant, indicating the mechanistic need for the PDZ motif of SERT in PDGF signaling. Furthermore, coimmunoprecipitation experiments showed that SERT and PDGFRβ become physically associated upon PDGF stimulation. In total, the data show for the first time an important interactive relationship between SERT and the PDGFRβ in the production of PASMC proliferation triggered by PDGF that may be important in PH.
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Thies, Katie, Anisha Hammer, Blake Hildreth та ін. "BSCI-11. STROMAL PLATELET DERIVED GROWTH FACTOR RECEPTOR-β (PDGFRβ) PROMOTES BREAST CANCER BRAIN METASTASIS". Neuro-Oncology Advances 1, Supplement_1 (2019): i3. http://dx.doi.org/10.1093/noajnl/vdz014.009.
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Abstract Stromal platelet-derived growth factor receptor-beta (PDGFRβ) has emerged as an actionable mediator of breast tumor-stromal communication. As a receptor tyrosine kinase, PDGFRβ is activated by its ligand, PDGFB, which is released by neighboring tumor epithelium and endothelium. However, how PDGF signaling mediates breast cancer (BC) initiation, progression, and metastasis remains unclear. To evaluate PDGFRβ in this disease, we developed a mouse model of stromal-specific PDGFRβ activation using the Fsp-cre transgene previously published by our group. Mesenchymal-specific activation of PDGFRβ promotes preferential experimental brain metastasis of PDGFB-expressing mammary tumor cells when injected intravenously and accelerates intracranial tumor growth of these cells. Mammary tumor cells expressing low levels of PDGFB do not exhibit a similar increase in brain metastases in PDGFRβ mutant mice. To our knowledge, this is the first example where genetic manipulation of the stroma leads to an increased incidence of BCBM. Our pre-clinical data suggests that primary breast tumors that express high PDGFB could preferentially metastasize to the brain. To test this in patients, we analyzed PDGFB protein expression in a tissue microarray comprised of HER2-positive and triple negative BC primary tumors. While high PDGFB did not correlate with site-independent metastatic recurrence, it was prognostic of brain metastasis, mirroring our mouse data. Our findings suggest that high primary tumor PDGFB expression defines a subset of BC patients predisposed to brain metastases. These patients may benefit from therapeutic intervention of PDGFRβ signaling. To test this pre-clinically, we treated mice harboring intracranial tumors with the PDGFR-specific inhibitor, crenolanib. Excitingly, crenolanib treatment significantly inhibited the brain tumor burden in these mice. Combined, our findings (1) advocate that primary tumor expression of PDGFB is a novel prognostic biomarker for the development of BCBM and (2) support clinical trial evaluation of PDGFR inhibitors for the prevention and treatment of BCBM.
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Zhou, Lingli, Xiaowei Sun, Zijing Huang та ін. "Imatinib Ameliorated Retinal Neovascularization by Suppressing PDGFR-α and PDGFR-β". Cellular Physiology and Biochemistry 48, № 1 (2018): 263–73. http://dx.doi.org/10.1159/000491726.
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Background/Aims: Platelet-derived growth factors (PDGFs) have emerged as pivotal in pathological angiogenesis, which is a hallmark of various tumors and retinal diseases. Here we evaluated the anti-angiogenic effect of imatinib, an inhibitor of PDGF receptors α and β (PDGFR-α and -β), in retinal neovascularization using an oxygen-induced retinopathy (OIR) model. Methods: The OIR model was established and given imatinib or vehicle treatments daily from P12 to P16. At the peak of angiogenesis at P17, the neovascularization area was quantified on retinal whole-mounts with isolectin B4 staining. Immunofluorescence staining and western blots were used to determine the effect of imatinib on different vascular cells and the pathway molecules involved. Results: Imatinib effectively suppressed pathological angiogenesis in OIR mice and reduced the number of all three types of vascular cells, including endothelial cells, pericytes, and smooth muscle cells. Moreover, the expression and activation of PDGFR-α and -β were inhibited by imatinib. The imatinib-treated OIR mice presented with reduced expression of other potent pro-angiogenic factors such as VEGF and FGF2. No obvious retinal or systemic side effects were observed in the imatinib treatment group. Conclusions: Imatinib appears to be safe and effective in suppressing retinal neovascularization. Targeting PDGFs/PDGFRs may also be important for anti-angiogenic treatment and offer a viable alternative treatment for retinal angiogenic diseases.
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Sugg, Kristoffer B., James F. Markworth, Nathaniel P. Disser, et al. "Postnatal tendon growth and remodeling require platelet-derived growth factor receptor signaling." American Journal of Physiology-Cell Physiology 314, no. 4 (2018): C389—C403. http://dx.doi.org/10.1152/ajpcell.00258.2017.
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Platelet-derived growth factor receptor (PDGFR) signaling plays an important role in the fundamental biological activities of many cells that compose musculoskeletal tissues. However, little is known about the role of PDGFR signaling during tendon growth and remodeling in adult animals. Using the hindlimb synergist ablation model of tendon growth, our objectives were to determine the role of PDGFR signaling in the adaptation of tendons subjected to a mechanical growth stimulus, as well as to investigate the biological mechanisms behind this response. We demonstrate that both PDGFRs, PDGFRα and PDGFRβ, are expressed in tendon fibroblasts and that the inhibition of PDGFR signaling suppresses the normal growth of tendon tissue in response to mechanical growth cues due to defects in fibroblast proliferation and migration. We also identify membrane type-1 matrix metalloproteinase (MT1-MMP) as an essential proteinase for the migration of tendon fibroblasts through their extracellular matrix. Furthermore, we report that MT1-MMP translation is regulated by phosphoinositide 3-kinase/Akt signaling, while ERK1/2 controls posttranslational trafficking of MT1-MMP to the plasma membrane of tendon fibroblasts. Taken together, these findings demonstrate that PDGFR signaling is necessary for postnatal tendon growth and remodeling and that MT1-MMP is a critical mediator of tendon fibroblast migration and a potential target for the treatment of tendon injuries and diseases.
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Hirst, S. J., P. J. Barnes, and C. H. Twort. "PDGF isoform-induced proliferation and receptor expression in human cultured airway smooth muscle cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 270, no. 3 (1996): L415—L428. http://dx.doi.org/10.1152/ajplung.1996.270.3.l415.
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The effect of recombinant platelet-derived growth factor (PDGF) isoforms (PDGF-AA, -BB and -AB) on mitogenesis of human cultured airway smooth muscle (ASM) was examined using the MTT-reduction assay and [3H]thymidine incorporation. Results were correlated with expression of PDGF receptor (PDGFR)-alpha and -beta subunits in the absence and presence of fetal calf serum (FCS). When FCS was absent PDGF-AB and -BB were potent mitogens, whereas PDGF-AA was weakly mitogenic, evoking <20% of the maximum response induced by the B-chain isoforms. When FCS (2.5%) was present, all PDGF isoforms stimulated marked ASM proliferation with similar efficacy and potency. Cross-competition binding analysis in FCS-deprived cells revealed that ASM cells in culture express mainly PDGFR-beta. Preincubation with PDGF-AA or PDGFR-alpha neutralizing antiserum abolished PDGF-AA binding and decreased total receptor number by approximately 15%. The ratio of PDGFR-alpha to beta subunits was approximately 1:8, supported by intense immunofluorescence staining for PDGFR-beta and weak staining for PDGFR-alpha. In parallel studies, uptake of [3H]thymidine stimulated by PDGF-AA, but not PDGF-AB or -BB, was inhibited by PDGFR-alpha immobilization. Western immunoblot analysis confirmed expression of mature PDGFR-alpha and -beta subunits in ASM cells. FCS did not cause any detectable increase in PDGFR-alpha expression or in PDGF-AA binding. These data support a role for PDGFR-beta mediating ASM mitogenesis during FCS-free conditions, but in the presence of FCS, both PDGFR-alpha and -beta subunits are linked to mitogenesis. The enhanced mitogenicity of PDGF-AA in the presence of FCS was independent of any detectable upregulation of PDGFR-alpha, suggesting that the inability of PDGF-AA to promote mitogenesis in the absence of FCS is not simply due to relative numbers of PDGFR-alpha and PDGFR-beta.
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Haley, Stephen, Robert L. Price, Tara A. Bullard, and Louis Terracio. "Platelet-Derived Growth Factor (PDGF) Stimulates Embryonic Cardiac Growth and Myofibrillogenesis." Microscopy and Microanalysis 7, S2 (2001): 1024–25. http://dx.doi.org/10.1017/s1431927600031196.
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Congenital heart disease is a leading cause of death in children with about 40,000 babies born in America each year with congenital heart disease. Common problems include atrial septal defects, patent ductus arteriosus and ventricular septal defects. However, very little is known about the underlying causes of congenital heart disease or the embryonic origin of cardiac malformation. The goal of our recent research has been to examine the role that specific growth factors and their receptors play in the development of the contractile apparatus of the heart and the experiments reported here further define the role of PDGF-AA and the PDGF alpha-receptor (PDGFR-α) during early heart growth and morphogenesis.The PDGF ligand and receptor system consists of two well-characterized ligands, PDGF-A and B, and a third recently identified ligand, PDGF-C. The active forms of PDGFA and B exist as either AA or BB homodimers or an AB heterodimer. The PDGFR-α binds all of the dimers with high affinity while the PDGFR-β binds only the PDGF-BB homodimer with high affinity.
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Johnell, Matilda, Brit Sorensen, Lars Petersen, Carl-Henrik Heldin, and Agneta Siegbahn. "Regulation of chemotaxis by the cytoplasmic domain of tissue factor." Thrombosis and Haemostasis 93, no. 01 (2005): 27–34. http://dx.doi.org/10.1160/th04-07-0405.
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SummaryWe previously demonstrated that FVIIa bound to tissue factor (TF) induces a hyperchemotactic response towards PDGF-BB. The aim of the present study was to investigate the role of the cytoplasmic domain of TF in cell migration. Porcine aortic endothelial (PAE) cells expressing human PDGF β -receptors (PAE/ PDGFR β ) were transfected for expression of human wildtype TF (PAE/PDGFRβ ,TF), a construct lacking the cytoplasmic domain (PAE/PDGFRβ ,TF ∆ cyto), a construct with alanine replacement of serine 258 (PAE/PDGFRβ ,TFS258A), or a construct with alanine replacement of serine 253, 258 and 263 in the cytoplasmic domain (PAE/PDGFRβ ,TF3SA). All stably transfected cell lines expressed functional TF. Chemotaxis was analyzed in a modified Boyden chamber assay. PAE/PDGFRβ ,TF cells stinulated with FVIIa migrated towards a 100-fold lower concentration of PDGF-BB than in the absence of FVIIa,however,hyperchemotaxis was not seen in PAE/PDGFRβ ,TF ∆ cyto cells. PAE/ PDGFR β /TFS258A and PAE/PDGFRβ ,TF3SA cells responded to low levels of PDGF-BB, but migrated a significantly shorter distance than PAE/PDGFRβ ,TF cells. Thus, hyperchemotaxis towards PDGF-BB is likely to depend in part on phosphorylation of the cytoplasmic domain of TF.We conclude that the cytoplasmic domain of TF plays a pivotal role in modulating cellular migration response.Our results suggest that the FVIIa/TF complex mediates intracellular signaling by alternative signal transduction pathway(s).
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Plattner, Rina, Anthony J. Koleske, Andrius Kazlauskas, and Ann Marie Pendergast. "Bidirectional Signaling Links the Abelson Kinases to the Platelet-Derived Growth Factor Receptor." Molecular and Cellular Biology 24, no. 6 (2004): 2573–83. http://dx.doi.org/10.1128/mcb.24.6.2573-2583.2004.
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ABSTRACT The c-Abl nonreceptor tyrosine kinase is activated by growth factor signals such as the platelet-derived growth factor (PDGF) and functions downstream of the PDGF-β receptor (PDGFR) to mediate biological processes such as membrane ruffling, mitogenesis, and chemotaxis. Here, we show that the related kinase Arg is activated downstream of PDGFRs in a manner dependent on Src family kinases and phospholipase C γ1 (PLC-γ1)-mediated phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis, as we showed previously for c-Abl. PIP2, a highly abundant phosphoinositide known to regulate cytoskeletal and membrane proteins, inhibits the tyrosine kinase activities of both Arg and c-Abl in vitro and in cells. We now demonstrate that c-Abl and Arg form inducible complexes with and are phosphorylated by the PDGFR tyrosine kinase in vitro and in vivo. Moreover, c-Abl and Arg, in turn, phosphorylate the PDGFR. We show that c-Abl and Arg exhibit nonredundant functions downstream of the activated PDGFR. Reintroduction of c-Abl into Arg-Abl double-null fibroblasts rescues the ability of PLC-γ1 to increase PDGF-mediated chemotaxis, while reexpression of Arg fails to rescue the chemotaxis defect. These data show that, although both kinases are activated and form complexes with proteins in the PDGFR signaling pathway, only c-Abl functions downstream of PLC-γ1 to mediate chemotaxis.
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Valius, M., C. Bazenet, and A. Kazlauskas. "Tyrosines 1021 and 1009 are phosphorylation sites in the carboxy terminus of the platelet-derived growth factor receptor beta subunit and are required for binding of phospholipase C gamma and a 64-kilodalton protein, respectively." Molecular and Cellular Biology 13, no. 1 (1993): 133–43. http://dx.doi.org/10.1128/mcb.13.1.133.
Full textAbstract:
Binding of platelet-derived growth factor (PDGF) to the PDGF receptor (PDGFR) beta subunit triggers receptor tyrosine phosphorylation and the stable association of a number of signal transduction molecules, including phospholipase C gamma (PLC gamma), the GTPase activating protein of ras (GAP), and phosphatidylinositol-3 kinase (PI3K). Previous reports have identified three PDGFR tyrosine phosphorylation sites in the kinase insert domain that are important for stable association of GAP and PI3K. Two of them, tyrosine (Y) 740, and Y-751 are required for the stable association of PI3K, while Y-771 is required for binding of GAP. Here we present data for two additional tyrosine phosphorylation sites, Y-1009 and Y-1021, that are both in the carboxy-terminal region of the PDGFR. Characterization of PDGFR mutants in which these phosphorylation sites are substituted with phenylalanine (F) indicated that Y-1021 and Y-1009 were required for the stable association of PLC gamma and a 64-kDa protein, respectively. An F-1009/F-1021 double mutant selectively failed to bind both PLC gamma and the 64-kDa protein, whereas all of the carboxy-terminal mutants bound wild-type levels of GAP and PI3K. The carboxy terminus encodes the complete binding site for PLC gamma, since a phosphorylated carboxy-terminal fusion protein selectively bound PLC gamma. To determine the biological consequences of failure to associate with PLC gamma, we measured PDGF-dependent inositol phosphate production and initiation of DNA synthesis. The PDGFR mutants that failed to associate with PLC gamma were not able to mediate the PDGF-dependent production of inositol phosphates. Since tyrosine phosphorylation of PLC gamma enhances its enzymatic activity, we speculated that PDGFR mutants that failed to activate PLC gamma were unable to mediate its tyrosine phosphorylation. Surprisingly, the F-1021 receptor mediated readily detectable levels of PDGF-dependent PLC gamma tyrosine phosphorylation. Thus, the production of inositol phosphates requires not only PLC gamma tyrosine phosphorylation but also its association with the PDGFR. Comparison of the mutant PDGFRs' abilities to initiate PDGF-dependent DNA synthesis indicated that failure to associate with PLC gamma and produce inositol phosphates diminished the mitogenic response by 30%. In contrast, preventing the PDGFR from binding the 64-kDa protein did not compromise PDGF-triggered DNA synthesis at saturating concentrations of PDGF. Thus, it appears that phosphorylation of the PDGFR at Y-1021 is required for the stable association of PLC gamma to the receptor's carboxy terminus, the production of inositol phosphates, and initiation of the maximal mitogenic response.
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Valius, M., C. Bazenet, and A. Kazlauskas. "Tyrosines 1021 and 1009 are phosphorylation sites in the carboxy terminus of the platelet-derived growth factor receptor beta subunit and are required for binding of phospholipase C gamma and a 64-kilodalton protein, respectively." Molecular and Cellular Biology 13, no. 1 (1993): 133–43. http://dx.doi.org/10.1128/mcb.13.1.133-143.1993.
Full textAbstract:
Binding of platelet-derived growth factor (PDGF) to the PDGF receptor (PDGFR) beta subunit triggers receptor tyrosine phosphorylation and the stable association of a number of signal transduction molecules, including phospholipase C gamma (PLC gamma), the GTPase activating protein of ras (GAP), and phosphatidylinositol-3 kinase (PI3K). Previous reports have identified three PDGFR tyrosine phosphorylation sites in the kinase insert domain that are important for stable association of GAP and PI3K. Two of them, tyrosine (Y) 740, and Y-751 are required for the stable association of PI3K, while Y-771 is required for binding of GAP. Here we present data for two additional tyrosine phosphorylation sites, Y-1009 and Y-1021, that are both in the carboxy-terminal region of the PDGFR. Characterization of PDGFR mutants in which these phosphorylation sites are substituted with phenylalanine (F) indicated that Y-1021 and Y-1009 were required for the stable association of PLC gamma and a 64-kDa protein, respectively. An F-1009/F-1021 double mutant selectively failed to bind both PLC gamma and the 64-kDa protein, whereas all of the carboxy-terminal mutants bound wild-type levels of GAP and PI3K. The carboxy terminus encodes the complete binding site for PLC gamma, since a phosphorylated carboxy-terminal fusion protein selectively bound PLC gamma. To determine the biological consequences of failure to associate with PLC gamma, we measured PDGF-dependent inositol phosphate production and initiation of DNA synthesis. The PDGFR mutants that failed to associate with PLC gamma were not able to mediate the PDGF-dependent production of inositol phosphates. Since tyrosine phosphorylation of PLC gamma enhances its enzymatic activity, we speculated that PDGFR mutants that failed to activate PLC gamma were unable to mediate its tyrosine phosphorylation. Surprisingly, the F-1021 receptor mediated readily detectable levels of PDGF-dependent PLC gamma tyrosine phosphorylation. Thus, the production of inositol phosphates requires not only PLC gamma tyrosine phosphorylation but also its association with the PDGFR. Comparison of the mutant PDGFRs' abilities to initiate PDGF-dependent DNA synthesis indicated that failure to associate with PLC gamma and produce inositol phosphates diminished the mitogenic response by 30%. In contrast, preventing the PDGFR from binding the 64-kDa protein did not compromise PDGF-triggered DNA synthesis at saturating concentrations of PDGF. Thus, it appears that phosphorylation of the PDGFR at Y-1021 is required for the stable association of PLC gamma to the receptor's carboxy terminus, the production of inositol phosphates, and initiation of the maximal mitogenic response.
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Ball, Stephen G., C. Adrian Shuttleworth, and Cay M. Kielty. "Vascular endothelial growth factor can signal through platelet-derived growth factor receptors." Journal of Cell Biology 177, no. 3 (2007): 489–500. http://dx.doi.org/10.1083/jcb.200608093.
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Vascular endothelial growth factor (VEGF-A) is a crucial stimulator of vascular cell migration and proliferation. Using bone marrow–derived human adult mesenchymal stem cells (MSCs) that did not express VEGF receptors, we provide evidence that VEGF-A can stimulate platelet-derived growth factor receptors (PDGFRs), thereby regulating MSC migration and proliferation. VEGF-A binds to both PDGFRα and PDGFRβ and induces tyrosine phosphorylation that, when inhibited, results in attenuation of VEGF-A–induced MSC migration and proliferation. This mechanism was also shown to mediate human dermal fibroblast (HDF) migration. VEGF-A/PDGFR signaling has the potential to regulate vascular cell recruitment and proliferation during tissue regeneration and disease.
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Lei, Hetian, Cynthia X. Qian, Jinghu Lei, Luis J. Haddock, Shizuo Mukai, and Andrius Kazlauskas. "RasGAP Promotes Autophagy and Thereby Suppresses Platelet-Derived Growth Factor Receptor-Mediated Signaling Events, Cellular Responses, and Pathology." Molecular and Cellular Biology 35, no. 10 (2015): 1673–85. http://dx.doi.org/10.1128/mcb.01248-14.
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Platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) make profound contributions to both physiology and pathology. While it is widely believed that direct (PDGF-mediated) activation is the primary mode of activating PDGFRs, the discovery that they can also be activated indirectly begs the question of the relevance of the indirect mode of activating PDGFRs. In the context of a blinding eye disease, indirect activation of PDGFRα results in persistent signaling, which suppresses the level of p53 and thereby promotes viability of cells that drive pathogenesis. Under the same conditions, PDGFRβ fails to undergo indirect activation. In this paper, we report that RasGAP (GTPase-activating protein of Ras) prevented indirect activation of PDGFRβ. RasGAP, which associates with PDGFRβ but not PDGFRα, reduced the level of mitochondrion-derived reactive oxygen species, which are required for enduring activation of PDGFRs. Furthermore, preventing PDGFRβ from associating with RasGAP allowed it to signal enduringly and drive pathogenesis of a blinding eye disease. These results indicate a previously unappreciated role of RasGAP in antagonizing indirect activation of PDGFRβ, define the underlying mechanism, and raise the possibility that PDGFRβ-mediated diseases involve indirect activation of PDGFRβ.
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Reis, Rui M., Albino Martins, Susana A. Ribeiro та ін. "Molecular Characterization of PDGFR-α/PDGF-A and c-KIT/SCF in Gliosarcomas". Analytical Cellular Pathology 27, № 5-6 (2005): 319–26. http://dx.doi.org/10.1155/2005/347863.
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Gliosarcomas are rare and poorly characterized malignant brain tumors that exhibit a biphasic tissue pattern with areas of gliomatous and sarcomatous differentiation. These tumors are histological variants of glioblastoma, displaying a similar genetic profile and dismal prognosis. Up-regulation of PDGFR subfamily of tyrosine kinase members, PDGFR-α and c-Kit, and their intracellular effectors RAS/RAF/MAPK has a crucial role in the cancer development. In addition, signal transduction mediated by activating mutations of c-Kit and PDGFR can be effectively blocked by specific tyrosine kinase inhibitors, such as Imatinib mesylate. The aim of this study was to characterize the molecular alterations of PDGFR signaling in gliosarcomas. Six cases were analyzed by immunohistochemistry for the expression of PDGFR-α, c-Kit and their ligands PDGF-A and SCF, respectively. The cases were further evaluated for the presence of activating mutations of PDGFR-α (exons 12 and 18) and c-kit (exons 9, 11, 13, and 17), as well as B-RAF (exons 11 and 15). Expression of PDGF-A was found in all cases and co-expression of PDGFR-α was observed in three cases. Four cases showed expression of SCF, and c-Kit was observed only in one case that also expressed SCF. Generally, immunoreaction predominates in the glial component. The mutational analysis of PDGFR-α showed the presence of an IVS17-50insT intronic insertion in two cases, one of them also with a 2472C > T silent mutation; this silent mutation was also found in another case. Glioma cell line analysis of IVS17-50insT insertion showed no influence on PDGFR-α gene splicing. No mutations were detected in c-kit and B-RAF oncogenes. Our Results indicate that activating mutations of PDGFR-α, c-kit and B-RAF are absent in gliosarcomas. Nevertheless, the presence of a PDGFR-a/PDGFA and c-Kit/SCF autocrine/paracrine stimulation loop in a proportion of cases, supports the potential role of specific tyrosine kinase inhibitors in the treatment of gliosarcomas.
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Maudsley, Stuart, A. Musa Zamah, Nadeem Rahman, et al. "Platelet-Derived Growth Factor Receptor Association with Na+/H+ Exchanger Regulatory Factor Potentiates Receptor Activity." Molecular and Cellular Biology 20, no. 22 (2000): 8352–63. http://dx.doi.org/10.1128/mcb.20.22.8352-8363.2000.
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ABSTRACT Platelet-derived growth factor (PDGF) is a potent mitogen for many cell types. The PDGF receptor (PDGFR) is a receptor tyrosine kinase that mediates the mitogenic effects of PDGF by binding to and/or phosphorylating a variety of intracellular signaling proteins upon PDGF-induced receptor dimerization. We show here that the Na+/H+ exchanger regulatory factor (NHERF; also known as EBP50), a protein not previously known to interact with the PDGFR, binds to the PDGFR carboxyl terminus (PDGFR-CT) with high affinity via a PDZ (PSD-95/Dlg/Z0-1 homology) domain-mediated interaction and potentiates PDGFR autophosphorylation and extracellular signal-regulated kinase (ERK) activation in cells. A point-mutated version of the PDGFR, with the terminal leucine changed to alanine (L1106A), cannot bind NHERF in vitro and is markedly impaired relative to the wild-type receptor with regard to PDGF-induced autophosphorylation and activation of ERK in cells. NHERF potentiation of PDGFR signaling depends on the capacity of NHERF to oligomerize. NHERF oligomerizes in vitro when bound with PDGFR-CT, and a truncated version of the first NHERF PDZ domain that can bind PDGFR-CT but which does not oligomerize reduces PDGFR tyrosine kinase activity when transiently overexpressed in cells. PDGFR activity in cells can also be regulated in a NHERF-dependent fashion by stimulation of the β2-adrenergic receptor, a known cellular binding partner for NHERF. These findings reveal that NHERF can directly bind to the PDGFR and potentiate PDGFR activity, thus elucidating both a novel mechanism by which PDGFR activity can be regulated and a new cellular role for the PDZ domain-containing adapter protein NHERF.
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Madsen, Christine Vestergaard, Karina Dahl Steffensen, Marianne Waldstrøm, and Anders Jakobsen. "Immunohistochemical Expression of Platelet-Derived Growth Factor Receptors in Ovarian Cancer Patients with Long-Term Follow-Up." Pathology Research International 2012 (September 23, 2012): 1–8. http://dx.doi.org/10.1155/2012/851432.
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Introduction. The well-documented role of the PDGF system in tumor growth and angiogenesis has prompted the development of new biological agents targeting the PDGF system. The aim of the present study was to analyze the expression of the PDGF-receptors in ovarian cancer and to investigate its relation to histopathological parameters and long-term overall survival. Methods. The immunohistochemical expression of PDGFR-α and PDGFR-β was investigated in tumor and stromal cells in 170 patients with histologically verified epithelial ovarian cancer. Results. Almost half of the tumor specimens showed high expression of PDGFR-α and PDGFR-β in tumor cells (43% and 41%) and in stromal compartments (32% and 44%). There was a significant association between high expression of PDGFR-α and high expression of PDGFR-β in both tumor and stromal cells. Coexpression of PDGFR-α and PDGFR-β in stromal cells was seen more often in serous adenocarcinomas than in nonserous adenocarcinomas. No clear correlation between PDGFR expression and longterm overall survival or clinical parameters was found. Conclusions. PDGFR-α and PDGFR-β were expressed in a subset of ovarian carcinomas but did not show significant prognostic importance in this material.
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Osornio-Vargas, A. R., P. M. Lindroos, P. G. Coin, A. Badgett, N. A. Hernandez-Rodriguez, and J. C. Bonner. "Maximal PDGF-induced lung fibroblast chemotaxis requires PDGF receptor-alpha." American Journal of Physiology-Lung Cellular and Molecular Physiology 271, no. 1 (1996): L93—L99. http://dx.doi.org/10.1152/ajplung.1996.271.1.l93.
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Alteration of the platelet-derived growth factor (PDGF) receptor system could be important in enhancing the mitogenic and chemotactic potential of lung fibroblasts during pulmonary fibrogenesis. We previously reported that interleukin-1 beta (IL-1 beta) upregulates the PDGF receptor-alpha (PDGFR-alpha) gene, and in this study we sought to establish the importance of the PDGFR-alpha relative to the PDGFR-beta in mediating a chemotactic response to PDGF-AA, -AB, and -BB. Pretreatment of fibroblasts for 24 h with IL-1 beta increased chemotaxis to all three PDGF isoforms. IL-1 beta pretreatment markedly increased the maximal number of 125I-labeled PDGF-AA binding sites but did not change the number of 125I-PDGF-AB or PDGF-BB sites. However, IL-1 beta increased 125I-PDGFR-AB affinity twofold. Neomycin (5 mM) was used as a PDGFR-alpha antagonist and completely blocked 125I-PDGF-AA binding and PDGF-AA-induced chemotaxis. The binding affinity of 125I-PDGF-AB and 125I-PDGF-BB was increased two-to threefold by neomycin, and chemotaxis to PDGF-AB and PDGF-BB was enhanced. These results define a role for the PDGFR-alpha as a regulatory receptor subtype that is necessary for PDGF isoforms to exert maximal chemotaxis.
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Ding, Wei, Traci R. Knox, Renee C. Tschumper, et al. "Platelet-derived growth factor (PDGF)–PDGF receptor interaction activates bone marrow–derived mesenchymal stromal cells derived from chronic lymphocytic leukemia: implications for an angiogenic switch." Blood 116, no. 16 (2010): 2984–93. http://dx.doi.org/10.1182/blood-2010-02-269894.
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Abstract Malignant cells are capable of influencing the microenvironment in a manner that facilitates tumor cell survival. Bidirectional crosstalk between chronic lymphocytic leukemic (CLL) cells and marrow-derived mesenchymal stromal cells (MSCs) activates both cell types. In this study, we observed that the conditioned medium (CM) obtained from CLL cells was able to induce Akt activation in MSC. Subsequent studies investigated the mechanism of MSC activation mediated by CLL-CM. Platelet-derived growth factor receptors (PDGFRs) were selectively activated in MSCs by CLL-CM and found to be critical receptors for CLL-CM–driven MSC proliferation and MSC Akt activation. The known ligands of PDGFR, platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF), were detected in CLL-CM, but PDGF was the predominant ligand involved in the CM-mediated PDGFR activation. Both PDGF and VEGF were found to be elevated in the plasma of CLL patients with a positive association for high-risk factors and more advanced stage. Finally, we demonstrated that PDGF induced MSC VEGF production through a phosphatidylinositol 3-kinase (PI3K)–dependent mechanism. These results show that PDGF-PDGFR signaling influences at least the MSC in the microenvironment of CLL and may play a role in the induction of an angiogenic switch known to be permissive for disease progression.
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Shen, Jie, Yoko Ishii, Guihua Xu та ін. "PDGFR-β as a Positive Regulator of Tissue Repair in a Mouse Model of Focal Cerebral Ischemia". Journal of Cerebral Blood Flow & Metabolism 32, № 2 (2011): 353–67. http://dx.doi.org/10.1038/jcbfm.2011.136.
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Although platelet-derived growth factors (PDGFs) and receptors (PDGFRs) are abundantly expressed in the central nervous system, their functions largely remain elusive. We investigated the role of PDGFR-β in tissue responses and functional recovery after photothrombolic middle cerebral artery occlusion (MCAO). In the normal adult mouse brain, PDGFR-β was mainly localized in neurons and in pericyte/vascular smooth muscle cells (PC/vSMCs). From 3 to 28 days after MCAO, postnatally induced systemic PDGFR-β knockout mice (Esr-KO) exhibited the delayed recovery of body weight and behavior, and larger infarction volume than controls. In Esr-KO, PC/vSMC coverage was decreased and vascular leakage of infused fluorescent-labeled albumin was extensive within the ischemic lesion, but not in the uninjured cerebral cortex. Angiogenesis levels were comparable between Esr-KO and controls. In another PDGFR-β conditional KO mouse (Nestin-KO), PDGFR-β was deleted in neurons and astrocytes from embryonic day 10.5, but was preserved in PC/vSMCs. After MCAO, vascular leakage and infarction volume in Nestin-KO were worse than controls, but partly improved compared with Esr-KO. Astroglial scar formation in both Esr-KO and Nestin-KO was similarly reduced compared with controls after MCAO. These data suggested that PDGFR-β signaling is crucial for neuroprotection, endogenous tissue repair, and functional recovery after stroke by targeting neurons, PC/vSMCs, and astrocytes.
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Kohno, Takashi, Norifumi Urao, Takashi Ashino та ін. "IQGAP1 links PDGF receptor-β signal to focal adhesions involved in vascular smooth muscle cell migration: role in neointimal formation after vascular injury". American Journal of Physiology-Cell Physiology 305, № 6 (2013): C591—C600. http://dx.doi.org/10.1152/ajpcell.00011.2013.
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Platelet-derived growth factor (PDGF) stimulates vascular smooth muscle cell (VSMC) migration and neointimal formation in response to injury. We previously identified IQ-domain GTPase-activating protein 1 (IQGAP1) as a novel VEGF receptor 2 binding scaffold protein involved in endothelial migration. However, its role in VSMC migration and neointimal formation in vivo is unknown. Here we show that PDGF stimulation rapidly promotes IQGAP1 association with PDGF receptor-β (PDGFR) as well as IQGAP1 tyrosine phosphorylation in cultured VSMC. Overexpression or knockdown of IQGAP1 enhances or inhibits PDGFR autophosphorylation (p-PDGFR), respectively. Immunofluorescence and cell fractionation analysis reveals that PDGF-induced p-PDGFR localized in focal adhesions (FAs), but not caveolae/lipid rafts, is inhibited by IQGAP1 knockdown with siRNA. PDGF stimulation promotes IQGAP1 association with PDGFR/FA signaling protein complex. Functionally, IQGAP1 siRNA inhibits PDGF-induced FA formation as well as VSMC migration induced by PDGF. In vivo, IQGAP1 expression is markedly increased at neointimal VSMC in wire-injured femoral arteries. Mice lacking IQGAP1 exhibit impaired neointimal formation in response to vascular injury. In summary, IQGAP1, through interaction with PDGFR and FA signaling proteins, promotes activation of PDGFR in FAs as well as FA formation, which may contribute to VSMC migration and neointimal formation after injury. Our findings provide insight into IQGAP1 as a potential therapeutic target for vascular migration-related diseases.
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Valius, M., J. P. Secrist, and A. Kazlauskas. "The GTPase-activating protein of Ras suppresses platelet-derived growth factor beta receptor signaling by silencing phospholipase C-gamma 1." Molecular and Cellular Biology 15, no. 6 (1995): 3058–71. http://dx.doi.org/10.1128/mcb.15.6.3058.
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The beta receptor for platelet-derived growth factor (beta PDGFR) is activated by binding of PDGF and undergoes phosphorylation at multiple tyrosine residues. The tyrosine-phosphorylated receptor associates with numerous SH2-domain-containing proteins which include phospholipase C-gamma 1 (PLC gamma), the GTPase-activating protein of Ras (GAP), the p85 subunit of phosphatidylinositol 3 kinase (PI3K), the phosphotyrosine phosphatase Syp, and several other proteins. Our previous studies indicated that PI3K and PLC gamma were required for relay of the mitogenic signal of beta PDGFR, whereas GAP and Syp did not appear to be required for this response. In this study, we further investigated the role of GAP and Syp in mitogenic signaling by beta PDGFR. Focusing on the PLC gamma-dependent branch of beta PDGFR signaling, we constructed a series of mutant beta PDGFRs that contained the binding sites for pairs of the receptor-associated proteins: PLC gamma and PI3K, PLC gamma and GAP, or PLC gamma and Syp. Characterization of these mutants showed that while all receptors were catalytically active and bound similar amounts of PLC gamma, they differed dramatically in their ability to initiate DNA synthesis. This signaling deficiency related to an inability to efficiently tyrosine phosphorylate and activate PLC gamma. Surprisingly, the crippled receptor was the one that recruited PLC gamma and GAP. Thus, GAP functions to suppress signal relay by the beta PDGFR, and it does so by silencing PLC gamma. These findings demonstrate that the biological response to PDGF depends not only on the ability of the beta PDGFR to recruit signal relay enzymes but also on the blend of these receptor-associated proteins.
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Li Xia, Zhou, Yang Mo, Ye Jie Yu, and Beng H. Chong. "PDGFR Inhibitor Imatinib May be a Potent Drug in Treating Essential Thrombocythemia." Blood 128, no. 22 (2016): 5470. http://dx.doi.org/10.1182/blood.v128.22.5470.5470.
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Abstract Approximates 80% of essential thrombocythemia (ET) patients carrying JAK2, CALR, MPL mutations. However, there is still 20% of ET patients are negative for all three mutations. Our previous studies have demonstrated that platelet-derived growth factor (PDGF) and its receptor (PDGFR) has a potential effect in the regulation of hematopoiesis and megakaryopoiesis. Therefore, we speculated that PDGF/PDGFR may plays an important role in megakaryocyte/platelet related disease, such as ET. In this study, we found an increase of PDGF-BB and PDGFR expression in ET patients comparing to the normal persons. We then used the adjusted dosage of PDGF-BB (1.5ug/kg/d) to establish an ET mimic mouse model. We found that PDGF-BB can enhance platelet production in vivo significantly, while PDGFR inhibitor imatinib can block this effect. Bone marrow histology data also confirmed the megakaryopoiesis effect of PDGF, as shown by an increased number of megakaryocytes in PDGF-treated mouse. The addition of imatinib can block the effect, evident by a decrease number of megakaryocytes and an increase of apoptosis. Furthermore, we demonstrated that PDGF-BB activated theP-JAK2, the P-STAT3 and the P-AKT expression in the megakaryocytic cell line CHRF-288, while addition of imatinib can reduce the phosphorylation level of all three genes. Our results suggested that the overexpression of PDGF-BB and PDGFR may be important in the pathogenesis of ET, especially in the JAK2-mutation negative ET. The elevated PDGF-BB activates PDGFR with subsequently activation of the JAK2/ STAT3 and PI3K/AKT pathway. Imatinib may have an effect on treating ET via blocking PDGFR and the following JAK2/STAT3 and PI3K/AKT pathway. This study suggests that PDGF/PDGFR may be involved in the pathogenesis of essential thrombocythemia, and the expression of PDGF-BB and PDGFR is potential to be a diagnostic index of ET. Blockage of PDGFR by imatinib may be a new therapeutic target for ET. Figure 1 Effect of PDGF-BB on Jak2/Stat3 and PI3K/Akt pathway of megakaryocytes. Figure 1. Effect of PDGF-BB on Jak2/Stat3 and PI3K/Akt pathway of megakaryocytes. Figure 2 The platelet numbers and the megakaryocytes of each group mice. Figure 2. The platelet numbers and the megakaryocytes of each group mice. Figure 3 Potential mechanisms for imatinib in treating essential thrombocythemia. Figure 3. Potential mechanisms for imatinib in treating essential thrombocythemia. Disclosures No relevant conflicts of interest to declare.
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Liu, Chunsheng, Jiachu Li, Xiaoyu Xiang та ін. "PDGF receptor-α promotes TGF-β signaling in hepatic stellate cells via transcriptional and posttranscriptional regulation of TGF-β receptors". American Journal of Physiology-Gastrointestinal and Liver Physiology 307, № 7 (2014): G749—G759. http://dx.doi.org/10.1152/ajpgi.00138.2014.
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Platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β) signaling are required for hepatic stellate cell (HSC) activation under pathological conditions such as liver metastatic tumor growth. These two signaling pathways are functionally divergent; PDGF signaling promotes proliferation and migration of HSCs, and TGF-β induces transdifferentiation of quiescent HSCs into myofibroblasts. Although PDGF signaling is implicated in TGF-β-mediated epithelial mesenchymal transition of tumor cells, the role of PDGF receptors in TGF-β activation of HSCs has not been investigated. Here we report that PDGF receptor-α (PDGFR-α) is required for TGF-β signaling of cultured human HSCs although HSCs express both PDGF-α and -β receptors. PDGFR-α knockdown inhibits TGF-β-induced phosphorylation and nuclear accumulation of SMAD2 with no influence on AKT or ERK phosphorylation associated with noncanonical TGF-β signaling. PDGFR-α knockdown suppresses TGF-β receptor I (TβRI) but increases TβRII gene transcription. At the protein level, PDGFR-α is recruited to TβRI/TβRII complexes by TGF-β stimulation. PDGFR-α knockdown blocks TGF-β-mediated internalization of TβRII and induces accumulation of TβRII at the plasma membrane, thereby inhibiting TGF-β phosphorylation of SMAD2. Functionally, knockdown of PDGFR-α reduces paracrine effects of HSCs on colorectal cancer cell proliferation and migration in vitro. In mice and patients, colorectal cancer cell invasion of the liver induces upregulation of PDGFR-α of HSCs. In summary, our finding that PDGFR-α knockdown inhibits SMAD-dependent TGF-β signaling by repressing TβRI transcriptionally and blocking endocytosis of TGF-β receptors highlights a convergence of PDGF and TGF-β signaling for HSC activation and PDGFR-α as a therapeutic target for liver metastasis and other settings of HSC activation.
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Popova, Antonia P., J. Kelley Bentley, Tracy X. Cui, et al. "Reduced platelet-derived growth factor receptor expression is a primary feature of human bronchopulmonary dysplasia." American Journal of Physiology-Lung Cellular and Molecular Physiology 307, no. 3 (2014): L231—L239. http://dx.doi.org/10.1152/ajplung.00342.2013.
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Animal studies have shown that platelet-derived growth factor (PDGF) signaling is required for normal alveolarization. Changes in PDGF receptor (PDGFR) expression in infants with bronchopulmonary dysplasia (BPD), a disease of hypoalveolarization, have not been examined. We hypothesized that PDGFR expression is reduced in neonatal lung mesenchymal stromal cells (MSCs) from infants who develop BPD. MSCs from tracheal aspirates of premature infants requiring mechanical ventilation in the first week of life were studied. MSC migration was assessed in a Boyden chamber. Human lung tissue was obtained from the University of Rochester Neonatal Lung Biorepository. Neonatal mice were exposed to air or 75% oxygen for 14 days. PDGFR expression was quantified by qPCR, immunoblotting, and stereology. MSCs were isolated from 25 neonates (mean gestational age 27.7 wk); 13 developed BPD and 12 did not. MSCs from infants who develop BPD showed lower PDGFR-α and PDGFR-β mRNA and protein expression and decreased migration to PDGF isoforms. Lungs from infants dying with BPD show thickened alveolar walls and paucity of PDGFR-α-positive cells in the dysmorphic alveolar septa. Similarly, lungs from hyperoxia-exposed neonatal mice showed lower expression of PDGFR-α and PDGFR-β, with significant reductions in the volume of PDGFR-α-positive alveolar tips. In conclusion, MSCs from infants who develop BPD hold stable alterations in PDGFR gene expression that favor hypoalveolarization. These data demonstrate that defective PDGFR signaling is a primary feature of human BPD.
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Battegay, E. J., J. Rupp, L. Iruela-Arispe, E. H. Sage, and M. Pech. "PDGF-BB modulates endothelial proliferation and angiogenesis in vitro via PDGF beta-receptors." Journal of Cell Biology 125, no. 4 (1994): 917–28. http://dx.doi.org/10.1083/jcb.125.4.917.
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To delineate potential angiogenic roles of platelet-derived growth factor (PDGF), we have investigated PDGF and its receptors on bovine aortic endothelial cells that exhibit spontaneous angiogenesis in vitro (angiogenic endothelial cells). Initiation of cord/tube formation by angiogenic endothelial cells required bovine or human serum. Neutralization of PDGF-BB in human serum with a monoclonal anti-PDGF-BB antibody reduced cord/tube formation by 37 +/- 10%, whereas neutralizing anti-PDGF-AA and an IgG isotype-matched control antibody had no effect. DNA synthesis in response to PDGF-BB increased as the cords and tubes developed; furthermore, PDGF-BB induced the incorporation of BrdU in the nuclei of cells associated with these structures. PDGF beta-receptor (PDGF-beta) mRNA increased concomitantly with cord/tube formation, and PDGFR-beta were specifically localized by immunocytochemistry to developing and mature cords and tubes. However, PDGFR-beta transcripts and protein were undetectable in nonangiogenic endothelial cells, and PDGF alpha-receptor mRNA was not expressed in either endothelial cell strain. In contrast to nonangiogenic endothelial cells, angiogenic endothelial cells did not express the PDGF B-chain, the required ligand for the PDGFR-beta. We conclude that (a) PDGF-BB can contribute to angiogenesis in vitro, (b) PDGFR-beta are specific for cord/tube-forming endothelial cells and mediate endothelial proliferation and cord/tube formation, and (c) in angiogenic and nonangiogenic endothelial cells, the expression of PDGFR-beta and PDGF B-chain is inversely correlated. We therefore suggest that paracrine PDGF might amplify angiogenesis via direct action on endothelially expressed PDGFR-beta.
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Zemskov, Evgeny A., Elena Loukinova, Irina Mikhailenko, Richard A. Coleman, Dudley K. Strickland, and Alexey M. Belkin. "Regulation of Platelet-derived Growth Factor Receptor Function by Integrin-associated Cell Surface Transglutaminase." Journal of Biological Chemistry 284, no. 24 (2009): 16693–703. http://dx.doi.org/10.1074/jbc.m109.010769.
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A functional collaboration between growth factor receptors such as platelet derived growth factor receptor (PDGFR) and integrins is required for effective signal transduction in response to soluble growth factors. However, the mechanisms of synergistic PDGFR/integrin signaling remain poorly understood. Our previous work showed that cell surface tissue transglutaminase (tTG) induces clustering of integrins and amplifies integrin signaling by acting as an integrin binding adhesion co-receptor for fibronectin. Here we report that in fibroblasts tTG enhances PDGFR-integrin association by interacting with PDGFR and bridging the two receptors on the cell surface. The interaction between tTG and PDGFR reduces cellular levels of the receptor by accelerating its turnover. Moreover, the association of PDGFR with tTG causes receptor clustering, increases PDGF binding, promotes adhesion-mediated and growth factor-induced PDGFR activation, and up-regulates downstream signaling. Importantly, tTG is required for efficient PDGF-dependent proliferation and migration of fibroblasts. These results reveal a previously unrecognized role for cell surface tTG in the regulation of the joint PDGFR/integrin signaling and PDGFR-dependent cell responses.
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Nemoto, E., S. Kanaya, M. Minamibuchi, and H. Shimauchi. "Cleavage of PDGF Receptor on Periodontal Ligament Cells by Elastase." Journal of Dental Research 84, no. 7 (2005): 629–33. http://dx.doi.org/10.1177/154405910508400709.
Full textAbstract:
Human leukocyte elastase, a neutrophil serine protease, is considered to be a potential immunoregulatory protease. Since the PDGF receptor (PDGFR) on periodontal ligament (PDL) cells is a crucial element for various functions, such as wound healing in periodontal tissue, we investigated the effect of elastase on the expression of PDGFR on PDL cells by flow cytometry and Western blotting. We found that PDGFR-α disappeared with an increasing dose of elastase, and PDGFR-β was degraded into several fragments. Elastase degraded both receptors on fixed cells, indicating that the degradation resulted from direct proteolysis on the cell surface. Elastase also then disturbed the phosphorylation of ERK1/2, JNK/SARK, and p38, triggered by PDGF-AA and PDGF-BB, suggesting that elastase inhibited PDGFR-dependent cell activation in PDL cells. These results suggest that elastase may modulate the PDGF-mediated activity of PDL cells during periodontal wound healing.
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Karlsson, L., P. Lindahl, J. K. Heath, and C. Betsholtz. "Abnormal gastrointestinal development in PDGF-A and PDGFR-(alpha) deficient mice implicates a novel mesenchymal structure with putative instructive properties in villus morphogenesis." Development 127, no. 16 (2000): 3457–66. http://dx.doi.org/10.1242/dev.127.16.3457.
Full textAbstract:
Development of the gastrointestinal (GI) tract depends on reciprocal epithelial-mesenchymal cell signaling. Here, we demonstrate a role for platelet-derived growth factor-A (PDGF-A) and its receptor, PDGFR-(alpha), in this process. Mice lacking PDGF-A or PDGFR-(alpha) were found to develop an abnormal GI mucosal lining, including fewer and misshapen villi and loss of pericryptal mesenchyme. Onset of villus morphogenesis correlated with the formation of clusters of PDGFR-(alpha) positive cells, ‘villus clusters’, which remained located at the tip of the mesenchymal core of the growing villus. Lack of PDGF-A or PDGFR-(alpha) resulted in progressive depletion of PDGFR-(alpha) positive mesenchymal cells, the formation of fewer villus clusters, and premature expression of smooth muscle actin (SMA) in the villus mesenchyme. We found that the villus clusters were postmitotic, expressed BMP-2 and BMP-4, and that their formation correlated with downregulated DNA synthesis in adjacent intestinal epithelium. We propose a model in which villus morphogenesis is initiated as a result of aggregation of PDGFR-(α) positive cells into cell clusters that subsequently function as mesenchymal centers of signaling to the epithelium. The role of PDGF-A seems to be to secure renewal of PDGFR-(alpha) positive cells when they are consumed in the initial rounds of cluster formation.
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von Bubnoff, Nikolas, Sivahari P. Gorantla, Richard A. Engh, et al. "Sorafenib and Nilotinib Are Candidates to Overcome Imatinib Resistance in Myeloproliferation with FIP1L1-PDGFRA." Blood 114, no. 22 (2009): 2912. http://dx.doi.org/10.1182/blood.v114.22.2912.2912.
Full textAbstract:
Abstract Abstract 2912 Poster Board II-888 Constitutively activated variants of PDGFRA, PDGFRB can be found in a subset of patients with myeloid neoplasms associated with eosinophilia. The most common is FIP1L1-PDGFRA (FP). Patients with PDGFR-A and -B rearranged myeloproliferation respond to treatment with imatinib. However, single cases of clinical resistance due to a secondary FP/T674I mutation have been reported. In CML, more than 40 different exchanges have been described that confer imatinib resistance, and sequential treatment with imatinib and novel Abl kinase inhibitors has become reality. Nilotinib and sorafinib are potent alternative inhibitors of PDGFR-A and -B. We therefore hypothesized that available PDGFR kinase inhibitors might produce specific profiles of secondary FP kinase domain mutations mediating inhibitor resistance. To this aim, we selected clones of FP expressing Ba/F3 cells resistant to rising concentrations of imatinib, nilotinib, and sorafinib. In these, we identified 27 different PDGFRA kinase domain mutations. Imatinib, nilotinib and sorafenib produced distinct profiles of resistance mutations. During selection with imatinib, FP/T674I predominated with rising concentrations. FP/T674I corresponds to Bcr-Abl/T315I, which is frequently found in imatinib resistant CML. In contrast to imatinib, nilotinib and sorafenib produced a significantly lower frequency of resistant cell clones. Also, T674I disappeared at therapeutic nilotinib concentrations in favour of T674I+T874I and D842V. Sorafinib displayed a distinct profile of mutations including D842V, but not T674I. Following cloning and expression of all FP variants, dose-response analysis indicated that full cross-resistance to all three inhibitors was limited to D842V, whereas the gatekeeper T674I exchange retained sensitivity to sorafenib and nilotinib, and T674I+T874I was responsive to sorafenib only. In silico structure modelling indicated that differences in inhibitor response observed in distinct clusters of FP mutations identified in drug-resistant clones are based on differences of sorafenib versus imatinib and nilotinib in key drug - protein target interactions in PDGFR family kinases. Besides direct inhibitor binding effects, we propose that the identified exchanges shift an inactive-active conformation equilibrium and thereby affect binding of type II inhibitors like imatinib, nilotinib and sorafenib. Our results predict PDGFR variants that might come up in patients with myeloproliferation positive for PDGFR-A or -B fusions treated with imatinib, nilotinib or sorafenib. These findings will help in selection of an appropriate second line PDGFR kinase inhibitor when resistance to imatinib emerges, and will guide drug design. Moreover, our data can be translated to other neoplasms driven by activated forms of PDGFR-A or -B including GIST, CMML, and dermatofibrosarcoma protuberans. Disclosures: Off Label Use: Use of sorafenib and nilotinib in myeloproliferation with prominent eosinophilia.
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Cain, Jennifer A., Jay L. Grisolano, A. Douglas Laird, and Michael H. Tomasson. "Complete remission of TEL-PDGFRB–induced myeloproliferative disease in mice by receptor tyrosine kinase inhibitor SU11657." Blood 104, no. 2 (2004): 561–64. http://dx.doi.org/10.1182/blood-2003-11-3801.
Full textAbstract:
Abstract The TEL-PDGFRB fusion oncogene is associated with chronic myelomonocytic leukemia (CMML) and results in the expression of a constitutively active tyrosine kinase. SU11657 is a multitargeted selective inhibitor of class III/V receptor tyrosine kinases, including the platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) receptors KIT and FLT3. SU11657 inhibited TEL/PDGFβR kinase activity at nanomolar concentrations and inhibited TELPDGFRB-mediated factor-independent growth in myeloblastic 32D cells. Daily oral administration of SU11657 at 40 mg/kg suppressed myeloproliferation and significantly prolonged survival in TELPDGFRB mice treated prior to disease development, as well as in those with large tumor burdens. Our findings suggest that SU11657 or similar agents may have therapeutic potential in humans with hematologic malignancies expressing PDGFR fusion oncogenes. (Blood. 2004;104:561-564)
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Aubert, J. D., S. Hayashi, J. Hards, T. R. Bai, P. D. Pare, and J. C. Hogg. "Platelet-derived growth factor and its receptor in lungs from patients with asthma and chronic airflow obstruction." American Journal of Physiology-Lung Cellular and Molecular Physiology 266, no. 6 (1994): L655—L663. http://dx.doi.org/10.1152/ajplung.1994.266.6.l655.
Full textAbstract:
The airway walls of patients who have asthma or chronic obstructive pulmonary disease (COPD) are thickened by an increase in the amount of smooth muscle and connective tissue. Platelet-derived growth factor (PDGF) is a candidate cytokine for this increase because it can produce smooth muscle proliferation in vitro. The present study was designed to examine the expression of PDGF and its receptor (PDGFR) in lungs from six asthmatics, six patients with COPD, and six patients with normal lung function. PDGF was immunolocalized to tissue macrophages, but the number of PDGF-positive cells was similar in all three groups. PDGFR-beta was rarely expressed on interstitial cells, and, occasionally, on bronchial epithelium. Northern blotting, performed on tissue from the same groups, showed a positive correlation of PDGF(B) with PDGFR-beta mRNA level (r = 0.74, P < 0.001) and a higher abundance of PDGF(B) and PDGFR-beta mRNA in the asthmatics vs. the COPD (P < 0.05). We conclude that PDGF and its receptor are expressed in human lungs but do not correlate closely with the structural changes in diseased airways.
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Aversa, A., S. Basciani, P. Visca, et al. "Platelet-derived growth factor (PDGF) and PDGF receptors in rat corpus cavernosum: changes in expression after transient in vivo hypoxia." Journal of Endocrinology 170, no. 2 (2001): 395–402. http://dx.doi.org/10.1677/joe.0.1700395.
Full textAbstract:
Platelet-derived growth factor (PDGF) overactivity has been implicated in atherosclerosis and several fibrotic conditions including lung and kidney fibrosis, liver cirrhosis and myelofibrosis. Low oxygen tension (hypoxia) is a known stimulus for transcriptional induction of PDGF ligand and receptor genes in different tissues. We studied the expression and localization of PDGF-A, PDGF-B, and PDGF receptor (PDGFR)-alpha and -beta subunits in adult rat isolated corpus cavernosum (CC) under generalized transient hypoxia (pO(2) 10%) in comparison with normoxic conditions. Semi-quantitative RT-PCR analysis of mRNA extracted from rat penis showed higher amounts of PDGF-A, PDGF-B and PDGFR-beta mRNA transcripts in hypoxic versus normoxic animals. The immunohistochemical analysis showed that the localization of PDGF subunits and PDGFR-beta was confined to the cytoplasm of the perivascular smooth muscle cells, endothelium and trabecular fibroblasts. Our findings indicate that transient low oxygen tension induces PDGF overexpression in rat CC, which in the long term may lead to an increase of connective tissue production. We suggest that a local impairment of the PDGF/PDGFR system may contribute to CC fibrosis, which is an established cause of erectile dysfunction in man.
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Luk, Kathryn, Sonja Boatman, Katherine N. Johnson, et al. "Influence of Morphine on Pericyte-Endothelial Interaction: Implications for Antiangiogenic Therapy." Journal of Oncology 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/458385.
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Morphine stimulates tumor angiogenesis and cancer progression in mice. We examined if morphine influences endothelial-pericyte interaction via platelet-derived growth factor-BB (PDGF-BB) and PDGF receptor-β(PDGFR-β). Clinically relevant doses of morphine stimulated PDGF-BB secretion from human umbilical vein endothelial cells and activated PDGFR-βand mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) phosphorylation in human pericytes. Thesein vitroeffects of morphine were translated into promotion of tumor angiogenesis in a transgenic mice model of breast cancer when treated with clinically used dose of morphine. Increased vessel-associated immunoreactivity of desmin and PDGFR-βwas observed on pericytes in tumors of morphine-treated mice. These data suggest that morphine potentiates endothelial-pericyte interaction via PDGF-BB/PDGFR-βsignaling and promotes tumor angiogenesis, pericyte recruitment, and coverage of tumor vessels. We speculate that morphine may impair the effectiveness of antiangiogenic therapy by influencing vascular pericyte coverage.
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Lindroos, Pamela M., Yi-Zhe Wang, Annette B. Rice та James C. Bonner. "Regulation of PDGFR-α in rat pulmonary myofibroblasts by staurosporine". American Journal of Physiology-Lung Cellular and Molecular Physiology 280, № 2 (2001): L354—L362. http://dx.doi.org/10.1152/ajplung.2001.280.2.l354.
Full textAbstract:
Upregulation of the platelet-derived growth factor (PDGF) receptor-α (PDGFR-α) is a mechanism of myofibroblast hyperplasia during pulmonary fibrosis. We previously identified interleukin (IL)-1β as a major inducer of the PDGFR-α in rat pulmonary myofibroblasts in vitro. In this study, we report that staurosporine, a broad-spectrum kinase inhibitor, upregulates PDGFR-α gene expression and protein. A variety of other kinase inhibitors did not induce PDGFR-α expression. Staurosporine did not act via an IL-1β autocrine loop because the IL-1 receptor antagonist protein did not block staurosporine-induced PDGFR-α expression. Furthermore, staurosporine did not activate a variety of signaling molecules that were activated by IL-1β, including nuclear factor-κB, extracellular signal-regulated kinase, and c-Jun NH2-terminal kinase. However, both staurosporine- and IL-1β-induced phosphorylation of p38 mitogen-activated protein kinase and upregulation of PDGFR-α by these two agents was inhibited by the p38 inhibitor SB-203580. Finally, staurosporine inhibited basal and PDGF-stimulated mitogenesis over the same concentration range that induced PDGFR-α expression. Collectively, these data demonstrate that staurosporine is a useful tool for elucidating the signaling mechanisms that regulate PDGFR expression in lung connective tissue cells and possibly for evaluating the role of the PDGFR-α as a growth arrest-specific gene.
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Ricono, Jill M., Brent Wagner, Yves Gorin та ін. "PDGF receptor-β modulates metanephric mesenchyme chemotaxis induced by PDGF AA". American Journal of Physiology-Renal Physiology 296, № 2 (2009): F406—F417. http://dx.doi.org/10.1152/ajprenal.90368.2008.
Full textAbstract:
PDGF B chain or PDGF receptor (PDGFR)-β-deficient (−/−) mice lack mesangial cells. To study responses of α- and β-receptor activation to PDGF ligands, metanephric mesenchymal cells (MMCs) were established from embryonic day E11.5 wild-type (+/+) and −/− mouse embryos. PDGF BB stimulated cell migration in +/+ cells, whereas PDGF AA did not. Conversely, PDGF AA was chemotactic for −/− MMCs. The mechanism by which PDGFR-β inhibited AA-induced migration was investigated. PDGF BB, but not PDGF AA, increased intracellular Ca2+ and the production of reactive oxygen species (ROS) in +/+ cells. Transfection of −/− MMCs with the wild-type β-receptor restored cell migration and ROS generation in response to PDGF BB and inhibited AA-induced migration. Inhibition of Ca2+ signaling facilitated PDGF AA-induced chemotaxis in the wild-type cells. The antioxidant N-acetyl-l-cysteine (NAC) or the NADPH oxidase inhibitor diphenyleneiodonium (DPI) abolished the BB-induced increase in intracellular Ca2+ concentration, suggesting that ROS act as upstream mediators of Ca2+ in suppressing PDGF AA-induced migration. These data indicate that ROS and Ca2+ generated by active PDGFR-β play an essential role in suppressing PDGF AA-induced migration in +/+ MMCs. During kidney development, PDGFR β-mediated ROS generation and Ca2+ influx suppress PDGF AA-induced chemotaxis in metanephric mesenchyme.
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Schneider, Linda, Christian-Martin Stock, Peter Dieterich та ін. "The Na+/H+ exchanger NHE1 is required for directional migration stimulated via PDGFR-α in the primary cilium". Journal of Cell Biology 185, № 1 (2009): 163–76. http://dx.doi.org/10.1083/jcb.200806019.
Full textAbstract:
We previously demonstrated that the primary cilium coordinates platelet-derived growth factor (PDGF) receptor (PDGFR) α–mediated migration in growth-arrested fibroblasts. In this study, we investigate the functional relationship between ciliary PDGFR-α and the Na+/H+ exchanger NHE1 in directional cell migration. NHE1 messenger RNA and protein levels are up-regulated in NIH3T3 cells and mouse embryonic fibroblasts (MEFs) during growth arrest, which is concomitant with cilium formation. NHE1 up-regulation is unaffected in Tg737orpk MEFs, which have no or very short primary cilia. In growth-arrested NIH3T3 cells, NHE1 is activated by the specific PDGFR-α ligand PDGF-AA. In wound-healing assays on growth-arrested NIH3T3 cells and wild-type MEFs, NHE1 inhibition by 5′-(N-ethyl-N-isopropyl) amiloride potently reduces PDGF-AA–mediated directional migration. These effects are strongly attenuated in interphase NIH3T3 cells, which are devoid of primary cilia, and in Tg737orpk MEFs. PDGF-AA failed to stimulate migration in NHE1-null fibroblasts. In conclusion, stimulation of directional migration in response to ciliary PDGFR-α signals is specifically dependent on NHE1 activity, indicating that NHE1 activation is a critical event in the physiological response to PDGFR-α stimulation.
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Basciani, Sabrina, Gabriele De Luca, Susanna Dolci та ін. "Platelet-Derived Growth Factor Receptor β-Subtype Regulates Proliferation and Migration of Gonocytes". Endocrinology 149, № 12 (2008): 6226–35. http://dx.doi.org/10.1210/en.2008-0349.
Full textAbstract:
Proliferation and migration of gonocytes, the precursors of spermatogonial stem cells, to the germline niche in the basal membrane of the seminiferous tubules, are two crucial events that take place between postnatal d 0.5 (P0.5) and P5.0 in the mouse and involve a selection of the cells that are committed to the germline stem cells lineage. Here we show that from embryonic d 18.0 (E18) and up to P5, the gonocytes express platelet-derived growth factor (PDGF) receptor β-subtype (PDGFR-β) and that during the same time period, the Sertoli cells express PDGF-B and PDGF-D, both ligands for PDGFR-β. Inhibition of the PDGFR-β tyrosine kinase activity during the first five postnatal days provokes a profound reduction of gonocyte number through inhibition of their proliferation and induction of apoptosis. Moreover, we found that PDGFR-β ligands are chemotactic for gonocytes. These data suggest that PDGFR-β activation has the remarkable capability to drive the selection, survival, and migration of the gonocytes from the center of the seminiferous tubules to the testicular germline niche on the basal membrane.
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Cartel, Nicholas J., Jason Liu, Jinxia Wang та Martin Post. "PDGF-BB-mediated activation of p42MAPK is independent of PDGF β-receptor tyrosine phosphorylation". American Journal of Physiology-Lung Cellular and Molecular Physiology 281, № 4 (2001): L786—L798. http://dx.doi.org/10.1152/ajplung.2001.281.4.l786.
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Herein, we investigated the activity of mitogen-activated protein kinase (MAPK), a key component of downstream signaling events, which is activated subsequent to platelet-derived growth factor (PDGF)-BB stimulation. Specifically, p42MAPK activity peaked 60 min after addition of PDGF-BB, declined thereafter, and was determined not to be a direct or necessary component of glycosaminoglycan (GAG) synthesis. PDGF-BB also activated MAPK kinase 2 (MAPKK2) but had no effect on MAPKK1 and Raf-1 activity. Chemical inhibition of Janus kinase, phosphatidylinositol 3-kinase, Src kinase, or tyrosine phosphorylation inhibition of the PDGF β-receptor (PDGFR-β) did not abrogate PDGF-BB-induced p42MAPK activation or its threonine or tyrosine phosphorylation. A dominant negative cytoplasmic receptor for hyaluronan-mediated motility variant 4 (RHAMMv4), a regulator of MAPKK-MAPK interaction and activation, did not inhibit PDGF-BB-induced p42MAPK activation nor did a construct expressing PDGFR-β with cytoplasmic tyrosines mutated to phenylalanine. However, overexpression of a dominant negative PDGFR-β lacking the cytoplasmic signaling domain abrogated p42MAPKactivity. These results suggest that PDGF-BB-mediated activation of p42MAPK requires the PDGFR-β but is independent of its tyrosine phosphorylation.
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McGowan, Stephen E., та Diann M. McCoy. "Platelet-derived growth factor receptor-α and Ras-related C3 botulinum toxin substrate-1 regulate mechano-responsiveness of lung fibroblasts". American Journal of Physiology-Lung Cellular and Molecular Physiology 313, № 6 (2017): L1174—L1187. http://dx.doi.org/10.1152/ajplung.00185.2017.
Full textAbstract:
Platelet-derived growth factor (PDGF)-A, which only signals through PDGF-receptor-α (PDGFR-α), is required for secondary alveolar septal formation. Although PDGFR-α distinguishes mesenchymal progenitor cells during the saccular stage, PDGFR-α-expressing alveolar cells persist through adulthood. PDGF-A sustains proliferation, limits apoptosis, and maintains α-smooth muscle actin (α-SMA)-containing alveolar cells, which congregate at the alveolar entry ring at postnatal day (P)12. PDGFR-α-expressing, α-SMA-containing alveolar cells redistribute in the elongating septum, suggesting that they migrate to the alveolar entry rings, where mechanical tension is higher. We hypothesized that PDGFR-α and Ras-related C3 botulinum toxin substrate 1(Rac1) are required for mechanosensitive myofibroblast migration. Spreading of PDGFR-α-deficient lung fibroblasts was insensitive to increased rigidity, and their migration was not reduced by Rac1-guanine exchange factor (GEF)-inhibition. PDGFR-α-expressing fibroblasts migrated toward stiffer regions within two-dimensional substrates by increasing migrational persistence (durotaxis). Using a Förster resonance energy transfer (FRET) biosensor for Rac1-GTP, we observed that PDGFR-α was required for fibroblast Rac1 responsiveness to stiffness within a three-dimensional collagen substrate, which by itself increased Rac1-FRET. Rho-GTPase stabilized, whereas Rac1-GTPase increased the turnover of focal adhesions. Under conditions that increased Rac1-GTP, PDGFR-α signaled through both phosphoinositide-3-kinase (PIK) or Src to engage the Rac1 GEF dedicator of cytokinesis-1 (Dock180) and p21-activated-kinase interacting exchange factor-β (βPIX). In cooperation with collagen fibers, these signaling pathways may guide fibroblasts toward the more rigid alveolar entry ring during secondary septation. Because emphysema and interstitial fibrosis disrupt the parenchymal mechanical continuum, understanding how mechanical factors regulate fibroblast migration could elicit strategies for alveolar repair and regeneration.
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Jiang, Zhiyuan, Guoqiang Zhong, Lina Wen та ін. "The Role of Platelet-Derived Growth Factor-B/Platelet-Derived Growth Factor Receptor-β Signaling in Chronic Atrial Fibrillation". Cardiology 133, № 4 (2016): 242–56. http://dx.doi.org/10.1159/000442940.
Full textAbstract:
Objective: To explore the role of platelet-derived growth factor-B (PDGF-B)/platelet-derived growth factor receptor-β (PDGFR-β) signaling in chronic atrial fibrillation (AF). Methods: Thirty-nine AF patients and 33 patients with sinus rhythm (SR) were enrolled. Twenty canines were randomized into 5 groups: control, sham and AF lasting 1, 2 or 4 weeks. The AF canine models were made by rapid atrial pacing. Rat atrial fibroblasts were treated with PDGF-BB or PDGF-BB + PDGFR inhibitor AG1295, respectively. Gene expression in the right atrial appendage of patients, the left atrium of canines and rat atrial fibroblasts was measured by quantitative real-time PCR and Western blot, respectively. The degree of atrial fibrosis was evaluated by Masson trichrome staining. Results: The degree of atrial fibrosis and the expression of PDGF-B, PDGFR-β and collagen type I (COL1) in AF patients significantly increased compared to patients with SR. The degree of atrial fibrosis and the expression of PDGF-B and COL1 in canines increased progressively with the increased duration of AF. The expression of PDGFR-β increased progressively 2 weeks after AF. PDGF-BB promoted the proliferation and COL1 secretion of rat atrial fibroblasts. AG1295 attenuated these effects. Conclusions: Our study suggests that PDGF-B/PDGFR-β signaling, which promotes the proliferation and COL1 secretion of atrial fibroblasts, is an important contributor to atrial fibrosis in AF and may represent a novel target for the intervention of AF.
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Rolny, Charlotte, Ingrid Nilsson, Peetra Magnusson та ін. "Platelet-derived growth factor receptor-β promotes early endothelial cell differentiation". Blood 108, № 6 (2006): 1877–86. http://dx.doi.org/10.1182/blood-2006-04-014894.
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AbstractPlatelet-derived growth factor BB (PDGF-BB) has been assigned a critical role in vascular stability by promoting the recruitment of PDGF receptor-β–expressing perivascular cells. Here we present data indicating that early hematopoietic/endothelial (hemangio) precursors express PDGFR-β based on coexpression with CD31, vascular endothelial growth factor receptor-2, and CD41 in 2 models: mouse yolk sac (embryonic day 8 [E8]) and differentiating mouse embryonic stem cells (embryoid bodies). Expression of PDGFR-β on hemangioprecursor cells in the embryoid bodies gradually disappeared, and, at E14, expression appeared on perivascular cells. Activation of the PDGFR-β on the hemangioprecursors accelerated the differentiation of endothelial cells, whereas differentiation of the hematopoietic lineage was suppressed. In E9.5 yolk sacs derived from recombinant mice expressing kinase-active PDGFR-β with an aspartic acid to asparagine (D894N) replacement in the kinase activating loop and from mice with ubiquitous expression of PDGF-BB driven by the Rosa26 locus, the number of CD41-expressing early hematopoietic cells decreased by 36% and 34%, respectively, compared with staged wild-type littermates. Moreover, enhanced vascular remodeling was evident in the Rosa26–PDGF-BB yolk sacs. We conclude that PDGFR-β is expressed on early hemangioprecursor cells, regulating vascular/hematopoietic development.
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Ustach, Carolyn V., and Hyeong-Reh Choi Kim. "Platelet-Derived Growth Factor D Is Activated by Urokinase Plasminogen Activator in Prostate Carcinoma Cells." Molecular and Cellular Biology 25, no. 14 (2005): 6279–88. http://dx.doi.org/10.1128/mcb.25.14.6279-6288.2005.
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ABSTRACT Platelet-derived growth factor (PDGF) protein family members are potent mitogens and chemoattractants for mesenchymal cells. The classic PDGF ligands A and B are single-domain protein chains which are secreted as active dimers capable of activating their cognate PDGF receptors (PDGFRs). In contrast to PDGFs A and B, PDGF D contains an N-terminal complement subcomponent C1r/C1s, Uegf, and Bmp1 (CUB) domain and a C-terminal PDGF domain. PDGF D must undergo extracellular proteolytic processing, separating the CUB domain from the PDGF domain, before the PDGF domain can stimulate β-PDGFR-mediated cell signal transduction. Here, we report that prostate carcinoma cells LNCaP and PC3 autoactivate latent full-length PDGF D into its active form under serum-independent conditions and that this autoactivation is inhibited by PAI-1, a urokinase plasminogen activator (uPA)/tissue plasminogen activator (tPA) inhibitor. Interestingly, uPA, but not the closely related protease tPA, is capable of processing recombinant latent PDGF DD into the active form. We identify the uPA cleavage site between the CUB and PDGF domains of the full-length PDGF D by mutational analysis and show that PDGF D and uPA colocalize in human prostate carcinoma. This evidence provides a direct link between uPA- and PDGF D-mediated cell signaling, which may contribute to the progression of prostate cancer.