Academic literature on the topic 'Colorectal neoplasms Transcription'

Abstract The transcription factor NF-E2 is overexpressed in the vast majority of patients with Myeloproliferative Neoplasms (MPN). In Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF) NF-E2 levels are elevated independent of the presence or absence of the JAK2V617Fmutation. We have recently shown that NF-E2 overexpression in a murine model leads to an MPN phenotype followed by spontaneous transformation to acute leukemia in a subset of mice. We have demonstrated that increased NF-E2 transcription is mediated by the transcription factor and proto-oncogene AML-1, which is overexpressed in MPN patients, again irrespective of the JAK2V617Fstatus. AML-1 binds to a conserved enhancer region located 3500 bp upstream of the NF-E2 transcriptional start site. Since AML-1 responsive genes are often also inversely regulated by the tumor suppressor AML-2 (RUNX3), we investigated whether NF-E2 expression is affected by AML-2 as well. Using chomatin immunoprecipitation assays (ChIP) we show that AML-2 binds the NF-E2 enhancer in vivo at a site distinct from but in proximity to the three AML-1 sites in the -3500bp region. AML-2 binding strongly represses transcription off the NF-E2 enhancer in reporter gene assays. This repression is abrogated by site directed mutagenesis of the AML-2 recognition sequence. Likewise, lentivirally induced AML-2 expression drastically reduces the amount of NF-E2 protein in erythroid and myeloid cells. These data clearly demonstrate that NF-E2 expression is directly regulated by AML-2. AML-2 thus serves as a repressor on the hematopoietic NF-E2 gene, a function previously noted mainly in solid tumors. In primary cells from patients with polycythemia vera (PV) AML-2 mRNA expression is significantly reduced. Moreover, ChIP assays demonstrate that in primary PV cells, significantly less AML-2 is bound to the NF-E2 enhancer than in healthy controls. Decreased repression by AML-2 thus cooperates with increased AML-1 induced transcription to elevate NF-E2 levels in PV patients. It has been demonstrated that AML-2 expression can be regulated by two distinct epigenetic mechanisms. For one, DNA methylation of the AML-2 promoter has been reported to silence AML-2 expression in gastric, colorectal and bladder cancers. On the other hand, aberrant histone methylation in the promoter region can also silence AML-2 expression. Here we show that DNA methylation of the AML-2 promoter is unaltered in PV patients. Rather, PV patients display aberrant histone methylation in the AML-2 promoter. Compared to healthy controls, H3K27me3 is significantly increased and H3K4me3 is significantly decreased in primary PV cells. This results in an inactive chromatin conformation on the AML-2 promoter in PV patients. Moreover, we show here that the histone-lysine-methyl-transferase “enhancer of zeste homologue 2” (EZH2), which confers the K3K27me3 mark, binds to the AML-2 promoter and decreases AML-2 expression. PV patients demonstrate significantly increased levels of EZH2 binding to the AML-2 promoter Treatment of primary PV cells and MPN cell lines with 2'-deoxy-5-azacytidine (DAC, Decitabine) ex vivo reverses the altered histone methylation, restoring the pattern found in healthy controls and decreases EZH2 binding to the AML-2 promoter. At the same time, Decitabine treatment induces AML-2 protein expression, decreases EZH2 expression and reduces the elevated NF-E2 levels. Moreover, a post-PV AML patient receiving Decitabine, displayed normalization of AML-2 promoter histone methylation and EZH2 binding on day 8 and day 15 of treatment. Taken together our data demonstrate that epigenetic silencing of AML-2 contributes to the elevated NF-E2 expression observed in MPN patients. Treatment with Decitabine restores physiological histone modifications to the AML-2 locus and decreases NF-E2 levels by reactivating AML-2 expression. These data provide a molecular rationale for extending the clinical investigation of epigenetic modifiers such as Decitabine or Azacitidine, currently used in MDS and AML, to patients with MPNs. A phase I study using Azacitidine in high risk PMF patients is currently being planned by the MPD-RC. Disclosures: No relevant conflicts of interest to declare.

The Hippo signaling pathway is a highly conserved pathway involved in tissue development and regeneration that controls organ size through the regulation of cell proliferation and apoptosis. The core Hippo pathway is composed of a block of kinases, MST1/2 (Mammalian STE20-like protein kinase 1/2) and LATS1/2 (Large tumor suppressor 1/2), which inhibits nuclear translocation of YAP/TAZ (Yes-Associated Protein 1/Transcriptional co-activator with PDZ-binding motif) and its downstream association with the TEAD (TEA domain) family of transcription factors. This pathway was recently shown to be involved in tumorigenesis and metastasis in several cancers such as lung, breast, or colorectal cancers but is still poorly investigated in brain tumors. Gliomas are the most common and the most lethal primary brain tumors representing about 80% of malignant central nervous system neoplasms. Despite intensive clinical protocol, the prognosis for patients remains very poor due to systematic relapse and treatment failure. Growing evidence demonstrating the role of Hippo signaling in cancer biology and the lack of efficient treatments for malignant gliomas support the idea that this pathway could represent a potential target paving the way for alternative therapeutics. Based on recent advances in the Hippo pathway deciphering, the main goal of this review is to highlight the role of this pathway in gliomas by a state-of-the-art synthesis.

Special AT-rich sequence-binding protein 2 (SATB2) is a transcription factor expressed by colonic cryptic epithelium and epithelial neoplasms of the lower gastrointestinal (GI) tract, as well as by small bowel adenocarcinomas (SBAs), though at a lower rate. Nevertheless, up to now, only small SBA series, often including a very limited number of Crohn’s disease-associated SBAs (CrD-SBAs) and celiac disease-associated SBAs (CD-SBA), have been investigated for SATB2 expression. We evaluated the expression of SATB2 and other GI phenotypic markers (cytokeratin (CK) 7 and CK20, caudal type homeobox 2 (CDX2) and alpha-methylacyl-CoA racemase (AMACR)), as well as mismatch repair (MMR) proteins, in 100 SBAs, encompassing 34 CrD-SBAs, 28 CD-SBAs and 38 sporadic cases (Spo-SBAs). Any mutual association and correlation with other clinico-pathologic features, including patient prognosis, were searched. Twenty (20%) SATB2-positive SBAs (4 CrD-SBAs, 7 CD-SBAs and 9 Spo-SBAs) were identified. The prevalence of SATB2 positivity was lower in CrD-SBA (12%) in comparison with both CD-SBAs (25%) and Spo-SBAs (24%). Interestingly, six SBAs (two CD-SBAs and four Spo-SBAs) displayed a full colorectal carcinoma (CRC)-like immunoprofile (CK7−/CK20+/CDX2+/AMACR+/SATB2+); none of them was a CrD-SBA. No association between SATB2 expression and MMR status was observed. Although SATB2-positive SBA patients showed a more favorable outcome in comparison with SATB2-negative ones, the difference did not reach statistical significance. When cancers were stratified according to CK7/CK20 expression patterns, we found that CK7−/CK20- SBAs were enriched with MMR-deficient cases (71%) and patients with CK7−/CK20− or CK7−/CK20+ SBAs had a significantly better survival rate compared to those with CK7+/CK20− or CK7+/CK20+ cancers (p = 0.002). To conclude, we identified a small (6%) subset of SBAs featuring a full CRC-like immunoprofile, representing a potential diagnostic pitfall in attempts to identify the site of origin of neoplasms of unknown primary site. In contrast with data on colorectal carcinoma, SATB2 expression is not associated with MMR status in SBAs. CK patterns influence patient survival, as CK7−/CK20− cancers show better prognosis, a behavior possibly due to the high rate of MMR-deficient SBAs within this subgroup.

Background & Aims: Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas have been reported to be associated with an increased risk of developing extra-pancreatic malignancies. A common genetic background has been hypothesised to be responsible for such an association. Human chromosomal region 8q24 has been associated with many types of cancer. The majority of these associations lie at approximately 128 Mb on chromosome 8. We conducted a study in order to examine the association between IPMN and single nucleotide polymorphisms (SNPs) from the 8q24 region, namely rs10505477, rs6983267, rs7014346, rs6993464, previously reported to influence general cancer susceptibility. Methods. The study was performed on 117 IPMN cases and 231 controls. Cases were enrolled at the Digestive Endoscopy Unit, Policlinico Agostino Gemelli from January, 2010 to June, 2011, with either a prevalent or incident IPMN diagnosis. Status of SNPs was determined using a StepOne Real-time PCR system (Applied Biosystems) and TaqMan SNP Genotyping Assay™ 40X. Unconditional multiple logistic regression models were used to estimate odds ratios and 95% confidence intervals for the association of selected SNPs and IPMNs. Results. Cases were more likely to report a 1st degree family history of cancer (p<0.001), as well as heavy smoking (p=0.001) and heavy drinking habits (p<0.001). No significant association was observed between IPMN and selected SNPs. The results were confirmed also when stratified according to any 1st-degree family history of cancer. Conclusion. Patients with IPMN do not have a higher prevalence of SNPs in the human chromosomal region 8q24 in respect to the control population. Abbreviations: CASC8: cancer susceptibility candidate 8; CRC: colorectal cancer; ENPP2: ectonucleotide pyrophosphatase/phosphodiesterase 2; EPM: extra-pancreatic malignancy; eQTLs: expression quantitative trait loci; IPMN: intraductal papillary mucinous neoplasm; MYC: myelocytomatosis viral oncogene homolog gene; NOV: nephroblastoma over-expressed gene; PCR: polymerase chain reaction; POU5F1P1: POU class 5 homeobox 1 pseudogene 1 gene; S-MRCP: magnetic resonance cholangiopancreatography with secretin stimulation; SNP: single nucleotide polymorphism; TCF4: transcription factor 4.

Colon cancers arise from benign neoplasms and evolve into adenocarcinomas through a stepwise histological progression sequence, proceeding from either adenomas or hyperplastic polyps/serrated adenomas. Genetic alterations have been associated with specific steps in this polyp–adenocarcinoma sequence and are believed to drive the histological progression of colon cancer. Recently, epigenetic alterations, which include CGI (CpG island) DNA methylation, have been shown to occur in colon polyps and colon cancer. The aberrant methylation of genes appears to co-operate with the genetic alterations to drive the initiation and progression of colon polyps to colon cancer. CGI DNA methylation is an epigenetic mechanism that represses gene transcription in normal cellular processes, but it becomes excessive and aberrant in many neoplasms. The aberrant DNA methylation affects CpG-rich regions, called CGIs, in the 5′ region of genes and results in transcriptional silencing through effects on transcription factor binding and associated changes in chromatin structure. These hypermethylated genes are not only probable pathogenic events affecting colon-cancer formation, but also neoplasm-specific molecular events that may be useful as molecular markers for colon tumours. Furthermore, aberrant DNA methylation of tumour-suppressor genes may occur secondary to a genetic predisposition or to a field-cancerization effect in the colon and may be useful as molecular markers for the risk of developing colon cancer.

Background/Aims: Since the combined actions of lncRNAs and miRNAs have been considered to be involved in the occurrence and development of various neoplasms, the main purpose of this study was to discover whether and how lncRNA H19 and miR-194 influenced the epithelial-mesenchymal transition (EMT) process of colorectal adenocarcinoma (CRA). Methods: Totally 214 pairs of CRA and adjacent normal tissues were collected, and 5 human CRA cell lines (i.e. HCT116, HT-29, RKO SW280 and Lovo) were purchased. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was adopted to quantify the H19 and miR-194-5p expressions in cells and tissues. The expressions of FoxM1, E-cadherin, vimentin, N-cadherin were determined using western blot. On the side, si-H19, si-NC, miR-194-5p mimic, miR-194-5p inhibitor and negative control (NC) were transfected into CRA cell lines. Meanwhile, the invasive, migratory and proliferative conditions of the cells were assessed through transwell, wound healing and colony-forming experiments, with final verification of the relationship between H19 and miR-194-5p employing dual-luciferase reporter gene assay. Results: Highly-expressed H19, lowly-expressed miR-194-5p, low-grade differentiation and lymph node metastasis appeared as the independent predictors of unfavorable prognosis in CRA patients’ (all P< 0.05). It indicated that FoxM1 expression displayed positive correlations with H19 expression, yet negative associations with miR-194-5p expression within CRA tissues (P< 0.05). In addition, transfection of H19-siRNA and miR-145-5p mimic triggered a conspicuous increase in E-cadherin expression, as well as an evidently down-regulation in vimentin and N-cadherin expressions within HT29 and RKO cells (P< 0.05). On the other hand, the invasive and migratory capacities of CRA cells were significantly hindered (P< 0.05). Moreover, the luciferase reporter gene assay confirmed that H19 modified miR-194-5p expression through directly targeting at it (P< 0.05). Ultimately, FoxM1 could reverse the role of miR-194-5p in inhibiting invasion, migration and EMT of CRA cells (P< 0.05). Conclusion: LncRNA H19/miR-194/FoxM1 axis could serve as a profound target for the diagnosis and treatment of CRA.

ObjectiveCancer-associated fibroblasts (CAFs) influence the tumour microenvironment and tumour growth. However, the role of CAFs in colorectal cancer (CRC) development is incompletely understood.DesignWe quantified phosphorylation of STAT3 (pSTAT3) expression in CAFs of human colon cancer tissue using a tissue microarray (TMA) of 375 patients, immunofluorescence staining and digital pathology. To investigate the functional role of CAFs in CRC, we took advantage of two murine models of colorectal neoplasia and advanced imaging technologies. In loss-of-function and gain-of-function experiments, using genetically modified mice with collagen type VI (COLVI)-specific signal transducer and activator of transcription 3 (STAT3) targeting, we evaluated STAT3 signalling in fibroblasts during colorectal tumour development. We performed a comparative gene expression profiling by whole genome RNA-sequencing of fibroblast subpopulations (COLVI+ vs COLVI–) on STAT3 activation (IL-6 vs IL-11).ResultsThe analysis of pSTAT3 expression in CAFs of human TMAs revealed a negative correlation of increased stromal pSTAT3 expression with the survival of colon cancer patients. In the loss-of-function and gain-of-function approach, we found a critical role of STAT3 activation in fibroblasts in driving colorectal tumourigenesis in vivo. With different imaging technologies, we detected an expansion of activated fibroblasts in colorectal neoplasias. Comparative gene expression profiling of fibroblast subpopulations on STAT3 activation revealed the regulation of transcriptional patterns associated with angiogenesis. Finally, the blockade of proangiogenic signalling significantly reduced colorectal tumour growth in mice with constitutive STAT3 activation in COLVI+ fibroblasts.ConclusionAltogether our work demonstrates a critical role of STAT3 activation in CAFs in CRC development.

2564 Background: HIF-1 is a transcription factor that regulates expression of many key genes, notably those switching cell metabolism to anaerobic glycolysis and inducing neovascularization in response to hypoxia. Increased HIF-1α levels are associated with poor prognosis in several neoplasms. EZN-2968 is a potent locked nucleic acid antisense oligonucleotide suppressing HIF-1α mRNA translation in vitro (IC50 ∼1–5 nM). Methods: This study was designed to determine the safety, tolerability, PK, maximum tolerated dose, recommended dose, and preliminary evidence of antitumor activity of EZN-2968. Pts with advanced malignancies were treated with EZN-2968 administered as a daily 2-hr IV infusion x 5 days every 4 weeks using a 3+3 dose-escalating design. Dose escalation was based on toxicities observed during Cycle 1. Results: 19 pts (11 men; median age = 60 y [47–79 y]) were treated with EZN-2968 doses of 0.5 (3 pts), 0.8 (3 pts), 1.2 (3 pts), 1.8 (4 pts), 2.7 (3 pts), and 4.1 (3 pts) mg/kg/day. Tumor types included colorectal cancer (7 pts); renal cancer (4 pts); soft-tissue sarcoma (STS; 2 pts); angiosarcoma (1 pt); melanoma (1 pt); and breast, ovarian, pancreatic, and prostate cancers (1 pt each). No dose-limiting toxicities were observed. The most common adverse events (Aes) were vomiting (32%); fatigue (26%); and anemia, diarrhea, nausea, and tumor pain (each 21%). Most Aes were Grade 1 or 2. Plasma PK for Day 1 is tabulated below. Stable disease was observed for 1 pt with angiosarcoma (28 wks) and 1 pt with renal cancer (12 wks). Conclusions: EZN-2968 was well tolerated in previously treated pts with advanced malignancies. PK data do not show accumulation of EZN-2968. Dose escalation is ongoing; final results will be presented at the meeting. Durable stable disease has been observed. [Table: see text] [Table: see text]

Fibroblast growth factor 19 (FGF19) promotes tumor growth in various types of cancer, but its function has not been investigated in the context of colorectal adenoma. Here, we report that FGF19 expression was greater in colorectal adenoma than in normal tissues, as measured by an enzyme-linked immunosorbent assay, quantitative reverse-transcription PCR and immunohistochemistry. FGF19 expression was also elevated in a subset of human colon cancer cell lines. Moreover, FGF receptor 4 (FGFR4), the cognate receptor for FGF19, was upregulated in colorectal adenoma tissues. Lipid levels and body mass index values strongly correlated with FGF19 and FGFR4 levels in patients with colon adenomas. These observations indicate that the FGF19/FGFR4 pathway may be involved in the development of neoplasia, and that FGF19 may be a valuable diagnostic marker for the identification of patients with colorectal adenomas.

The DNA damage response (DDR) pathway is a complicated network of interacting proteins that function to sense and remove DNA damage. Upon exposure to DNA damage, a signaling cascade is generated. The damage is either removed, restoring the original genetic sequence, or apoptosis is activated. In the absence of DDR, cells are unable to effectively process DNA damage. Unprocessed DNA damage can lead to chromosomal changes, gene mutations, and malignant transformation. Thus, the proteins involved in DDR are critical for maintaining genomic stability. One essential DDR protein is the BRCA1 Associated C-terminal Helicase, BACH1. BACH1 was initially identified through its direct association with the BRCT domain of the Breast Cancer Associated Gene, BRCA1. Similar to BRCA1, germline mutations in BACH1were identified in patients with early onset breast cancer. Interestingly, the disease-associated mutations in BACH1 were shown to have altered helicase activity in vitro, providing a direct link between BACH1 helicase activity and disease development. The correlation between BACH1 and cancer predisposition was further confirmed by the identification of BACH1 as the cancer syndrome Fanconi anemia (FA) gene product, FANCJ. Similar to other FA proteins, suppression of FANCJ leads to decreased homologous recombination, enhanced sensitivity to DNA interstrand crosslinking (ICL) agents, and chromosomal instability. In an effort to further understand the function of FANCJ in DDR, FANCJ was shown to directly associate with the mismatch repair (MMR) protein MLH1. This interaction is facilitated by lysines 141 and 142 within the helicase domain of FANCJ. Importantly, the FANCJ/MLH1 interaction is critical for ICL repair. Furthermore, in an attempt to dissect the binding site of FANCJ on MLH1, we discovered an HNPCC associated MLH1 mutation (L607H) that has intact mismatch repair, but lacks FANCJ interaction. In contrast to the MLH1 interaction, the FANCJ/BRCA1 interaction was not required for correcting the cellular defects in FANCJ null cells. Thus, in an effort to understand the functional significance of the FANCJ/BRCA1 interaction, we discovered that FANCJ promotes Pol η dependent translesion synthesis (TLS) bypass when uncoupled from BRCA1. In this thesis, we provide evidence suggesting that FANCJ and MLH1 are functionally linked and that the interaction of these proteins is critical for repair choice.