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1
Quesnel, Bruno. "Gene p16 ink4a , p15 ink4b, et hemopathies malignes." Lille 2, 1997. http://www.theses.fr/1997LIL2T009.
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Carter, Tina. "A study of the INK4A/ARF and INK4B loci in childhood acute lymphoblastic leukaemia using quantitative real time polymerase chain reaction." University of Western Australia. School of Paediatrics and Child Health, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0077.
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[Truncated abstract] Childhood acute lymphoblastic leukaemia (ALL) accounts for the largest number of cases of childhood cancer (25-35%) and is the primary cause of cancer related morbidity. Today more than 76% of children with ALL are alive and disease free at 5 years. Approximately one in 900 individuals between the ages of 16 and 44 years is a survivor of childhood cancer. In contrast, those patients who relapse with childhood ALL currently have a 6-year event free survival of 20-30%. The short arm of chromosome 9p is mutated or deleted in many cancers including leukaemia. Aberrations of the INK4A/ARF and INK4B loci at the 9p21 band are linked to the development and progression of cancer. In murine cancer models there is evidence to suggest that mutations of Ink4a/Arf and p53 gene loci promote resistance to chemotherapeutic drugs known to trigger apoptosis. The initial aim of this project was to develop an accurate, reproducible method to detect deletions at the INK4A/ARF locus in patient bone marrow specimens. This technique was then applied to detect the incidence of deletions of this locus in childhood ALL specimens. The hypothesis developed was that deletion at the INK4A/ARF locus at diagnosis in childhood ALL is an independent prognostic marker and is involved in disease progression. A secondary aim of this study was to determine which deletions at the INK4A/ARF and INK4B loci are the most relevant in leukaemogenesis in childhood ALL. ... This study has shown that deletion of the INK4A/ARF locus is an independent prognostic indicator in childhood ALL. In addition, the frequency of deletion at the INK4A/ARF and INK4B loci is increased at relapse compared to diagnosis in childhood ALL. In the relapse study group, deletion of the p16INK4A gene at diagnosis was associated with a decreased median time to relapse compared to other genes analysed. Murine studies suggest that such deletions may result in an increased resistance to chemotherapy. If the findings from this study are confirmed in a larger cohort, it is expected that therapeutic interventions based on assessment of the p16INK4A gene in diagnostic childhood ALL specimens will be implemented to prevent relapse in standard risk patients and help to improve the outcome in high risk patients.
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Li, Junan. "Structural and functional studies on Tumor Suppressor INK4 Proteins P16(INK4A) and P18(INK4C) /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488194825665461.
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Tanaka, Tomoyuki. "High incidence of allelic loss on chromosome 5 and inactivation of p15^{INK4B} and p16^{INK4A} tumor suppressor genes in oxystress-induced renal cell carcinoma of rats." Kyoto University, 1999. http://hdl.handle.net/2433/181736.
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Draney, Carrie. "Overexpression of HDAC1 Induces Functional β-cell Mass." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6573.
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Type 2 diabetes is a metabolic disorder that results in β-cell dysfunction and ultimate destruction, and leads to impaired glucose homeostasis. High rates of proliferation and differentiation of pancreatic β-cells occurs mostly during neonatal development. However, research shows these mechanisms remain intact as β-cell proliferation has been observed during pregnancy and obesity. We have shown that overexpression of the β-cell transcription factor Nkx6.1 is sufficient to induce β-cell proliferation. Exploration of the transcriptional targets of Nkx6.1 has identified histone deacetylase 1 (HDAC1) as a down-stream target of Nkx6.1. Here we demonstrate that HDAC1 overexpression is sufficient to induce β-cell proliferation, enhance β-cell survival upon exposure to apoptotic stimuli and maintains glucose stimulated insulin secretion (GSIS). Our data suggests overexpression of HDAC1 leads to p15/INK4b suppression, a cell cycle inhibitor, potentially explaining the mechanism behind these observed effects. These data demonstrate that HDAC1 overexpression is sufficient to induce β-cell proliferation and enhance cell survival while maintaining glucose stimulated insulin secretion.
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Dodge, Jonathan Eldon. "Selective variegated methylation of the p15/INK4B CpG island is a high frequency event in acute myeloid leukemia (AML)." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284143.
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We attempted to define target genes that were inactivated in acute myeloid leukemia (AML) by DNA methylation. We hypothesized that hypermethylation of 51 CpG islands is associated with transcriptional silencing of the corresponding gene and participates in either the emergence of drug resistance or the conversion of normal cells to cancer cells. To test this hypothesis the DNA methylation status of the 5' CpG islands of dCK containing 49 CpGs, p15 containing 80 CpGs, and p16 containing 53 CpGs was determined by sodium bisulfite sequencing of normal human peripheral blood lymphocytes (PBL) and bone marrow (NBM), human leukemia cell lines, and cytosine-arabinoside (ara-C)-resistant adult acute myeloid leukemia (AML) patients. In PBL and NBM dCK, p15, and p16 were all unmethylated. dCK was unmethylated in the paired ara-C-sensitive (/S) ara-C-resistant (/R) leukemia cell lines HL60/S & /R and K562/S & /R, and in the 8 AML patients analyzed. p16 was unmethylated in KG-l and KG-1a and both had detectable p16 mRNA and protein. None of the 8 AML patients had aberrant methylation of p16. For p15, a variegated pattern of aberrant methylation was found in KG-1, and complete methylation of p15 was found in KG-1a. The variegated pattern of p15 methylation seen in KG-1 and the complete methylation seen in KG-1a were both associated with no detectable p15 mRNA or protein. p15 was aberrantly methylated in 6 of the 8 AML patients, 5 had a variegated pattern of methylation, and 1 showed complete methylation. We next introduced ectopic p15 and p16 into the p15 and p16 negative human T-cell lymphocytic leukemia cell line Jurkat. The p15 positive clones grew at a slower rate than the parent cell or p16 positive clones as measured by growth in liquid culture and MTS assay. cDNA microarray expression analysis differentiated p15 and p16 positive subclones from the parent cell line but not from each other. This suggests that despite the selective methylation of p15 but not p16 in AML, p15 and p16 are functionally similar.
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Nilsson, Lisa. "The cell cycle regulators p18Ink4c and p19Ink4d : in vivo studies of their roles in tumorigenesis and development." Doctoral thesis, Umeå University, Molecular Biology (Faculty of Science and Technology), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1357.
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Progression through the G1, S, G2 and M phases of the cell cycle is controlled by cyclin-dependent kinases (Cdks) and cyclins. These proteins form active Cdk:cyclin complexes that phosphorylate specific substrates. The Cdk:cyclin complexes of the G1/S transition regulate the progression of cells into the S phase by phosphorylating the retinoblastoma protein (Rb). This prevents Rb from sequestering E2F, a transcription factor that induces expression of genes required for DNA synthesis. This process is in part regulated by a family of Cdk inhibitors (CKIs) called the Ink4 family (Inhibitors of Cdk4). The Ink4 family of CKIs consists of four members; p16Ink4a, p15Ink4b, p18Ink4c and p19Ink4d, and they bind specifically to Cdk4 and Cdk6, thereby negatively regulating their kinase activities and cell cycle progression. Because of its cell cycle inhibitory role, p16Ink4a is frequently mutated or deleted in human cancer, whereas the other Ink4 genes are only occasionally altered in cancer. The overall aim of this thesis was to study the roles of p18Ink4c and p19Ink4d using in vivo models of cancer and embryonic development. In paper I, we analyzed the tumor spectrum in mice lacking p53, Ink4c and Ink4d. p53 is a tumor suppressor and one of the most frequently mutated genes in human cancer. Mice carrying mutated p53 alleles are highly tumor-prone but develop predominantly lymphomas. However, the combined loss of p53 and Ink4c (but not Ink4d) caused a shift in the tumor spectrum to increased incidences of hemangiomas and hemangiosarcomas, as well as appearance of medulloblastomas, a tumor of the cerebellum. These data, revealed in the absence of p53, suggest a cell-type specific tumor suppressing role for p18Ink4c. In paper II, loss of Ink4c was evaluated in another tumor-prone mouse model; the Eµ-Myc mouse. This is a transgenic mouse overexpressing c-Myc in B cells causing clonal B cell lymphomas. Surprisingly, precancerous B cells and lymphomas from Eµ-Myc mice exhibited elevated levels of p18Ink4c mRNA and protein despite high rates of proliferation. Moreover, loss of Ink4c in this model did not affect the rate of cell proliferation or the onset of tumor development. We conclude from these studies that Ink4c is not an important tumor suppressor of Myc-induced lymphomas. To gain insight into the role of Ink4 genes in early vertebrate development, the African clawed frog, Xenopus laevis, was analyzed for the presence of Ink4 homologs. Paper III describes the cloning and characterization of a gene homologous to Ink4d, Xl-Ink4d. This CKI is expressed throughout frog embryo development, making Xl-Ink4d the only CKI present during the cleavage stages of X. laevis. Antisense morpholino oligonucleotides directed against Xl-Ink4d were used to knock down the protein level of Xl-Ink4d during development. This resulted in defects in head tissues and reduced expression of Twist, a gene important for neural crest cell migration. We therefore propose that Xl-Ink4d is important for proper neural crest differentiation in the frog.
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Thirukkumaran, P. "Regulation of INK4 gene expression in breast cancer." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0003/MQ35003.pdf.
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Voss, Martin Henner. "p16-INK4a controls the morphology program associated with cellular senescence." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976851105.
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Jones, Rebecca May. "Regulation and function of the INK4a/ARF tumour suppressor locus." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1444810/.
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The CDKN2a locus encodes two important tumour suppressors, pl61NK4a and ARF. The two genes share a common exon which is translated in different reading frames. pl6,NK4a binds to CDK4 and CDK6, preventing them from forming active complexes with D cyclins. As a result, pRb does not undergo the phosphorylation necessary for the transition from the G1 to S phase of the cell cycle. ARF inhibits the ubiquitination of p53 by MDM2, thereby causing the accumulation of p53. There is a growing awareness that the CDKN2a locus plays a central role in the cellular defences against transformation, and in the cellular response to stress. For example, pl6INK4a is involved in senescence, a permanent cell cycle arrest triggered in primary human fibroblasts in response to many stresses, including the overexpression of oncogenes. However, little is known about the regulation of pl6INK4a under these circumstances, and work in this thesis investigates this issue using overexpression of Myc as a model. The thesis also describes the characterisation of human diploid fibroblasts (Milan cells) from a patient homozygous for the R24P mutation of pl6INK4a. As this mutation is in exon la, ARF is unaffected. The mutant pl6INK4a cannot bind to CDK4, but retains some capacity to bind to CDK6. Milan cells have also been used in combination with shRNA targeting ARF to investigate the relative roles of pl6INK4a and ARF in the prevention of transformation. A panel of Milan cells were produced expressing telomerase, with combinations of Myc, Ras and shRNA targeting ARF, and the ability of the cells to grow in soft agar was assessed. A similar panel of Milan expressing p53 shRNA was also built up. These cells were used to investigate whether ablation of ARF can substitute for the loss of p53 function often associated with transformation, and to help identify which aspects of the p53 pathway are activated in the defence against transformation.
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Huot, Thomas. "Interplay of ID and INK4 proteins in cellular senecence." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407318.
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Gregory, Fiona Janet. "Functional analysis of p16'INK4a and p21'CIP1 in replicative senescence." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325915.
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Silva, Marcelo Magalhães. "Estudo de alterações genéticas associadas à leucemia/linfoma de células T do adulto no estado da Bahia." reponame:Repositório Institucional da FIOCRUZ, 2012. https://www.arca.fiocruz.br/handle/icict/4248.
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A leucemia/linfoma de células T do adulto (ATL) é uma severa doença linfoproliferativa de células T CD4+ associada ao HTLV-1. Por apresentar diferentes manifestações clínicas, essa neoplasia pode ser classificada em cinco formas: aguda, crônica, smoldering, linfomatosa e tumoral primária de pele. Embora alguns trabalhos venham estudando o processo oncogênico mediado pelo HTLV-1, diversos fatores responsáveis pelo desenvolvimento da ATL ainda permanecem desconhecidos. Este estudo teve como objetivo a investigação de alterações genéticas em células ATL (mutações pontuais em genes supressores de tumor e alterações microssatélites) e sua associação com a evolução clínica da doença e sobrevida dos pacientes. A presença de mutações pontuais nos supressores de tumor TP53, p15INK4B e p16INK4A foram avaliadas em 31 pacientes com diferentes formas da ATL (16 agudos, dez crônicos e cinco smoldering) por análise de seqüenciamento de DNA. Cinco pacientes (16%) apresentaram mutações pontuais no gene TP53, sendo que quatro dentre os mesmos foram classificados com a forma aguda. A presença de mutações nos genes avaliados foi associada com pior prognóstico em pacientes com a forma aguda. Em um dos pacientes incluídos neste trabalho (forma aguda) foi verificada a presença de alteração no éxon 2 do gene p16INK4A. Mutações pontuais não foram detectadas no gene p15INK4B em nenhum dos pacientes incluídos. Os marcadores D10S190, D10S191, D11S1391 e D18S21 foram utilizados para a análise de alterações microssatélites por metodologia semi-automatizada. Dentre os 25 pacientes ATL avaliados (seis agudos, oito crônicos, dez smoldering e um linfomatoso), sete apresentaram alterações microssatélites. Três desses pacientes apresentaram instabilidade (MSI), três pacientes apresentaram perda de heterozigosidade (LOH) e em um paciente foi verificado ambas as alterações. Na Bahia, mutações pontuais em TP53 foram detectadas principalmente na forma aguda da ATL e parece estar associada com pior prognóstico. Além disso, de acordo com nossos conhecimentos, este é o primeiro estudo a descrever tanto MSI com LOH em pacientes portando formas crônica e smoldering da ATL.
Adult T-cell leukemia/lymphoma (ATL) is a severe CD4+ lymphoproliferative disease associated to human T-cell lymphotropic virus type 1 (HTLV-1). ATL has different clinical manifestations and is classified in five clinical forms: acute, chronic, smoldering, lymphoma and primary cutaneous tumoral. Although the mechanisms of oncogenesis of the HTLV-1 have been investigated, the factors related to ATL development are still unknown. The goal of this study was to investigate genetic alterations in ATL cells (point mutations in tumor suppressor genes and microsatellite alterations) and their association with the clinical evolution of the disease and survival. The presence of point mutations in TP53, p15INK4B e p16INK4A were evaluated in 31 ATL patients (16 acute, ten chronic and five smoldering) by direct sequencing. Five of them (16%) had TP53 point mutations, four of them with the acute form of ATL. The presence of point mutations in this gene was associated to poor prognosis in acute patients. Only one case (acute form) has an alteration in the exon 2 of the p16INK4A gene. No point mutations of the p15INK4B were found in the patients included. The markers D10S190, D10S191, D11S1391 and D18S21 were considered for the microsatellite analysis using a semiautomated technique. From the twenty-five ATL cases included (six acute, eight chronic, ten smoldering and one lymphoma), seven showed microsatellite alteration. Among them, three patients had microsatellite instability (MSI), three had loss of heterozygosity and one patient presented both alterations. In Bahia, point mutations in TP53 were detected mainly in acute form of ATL and were associated to poor prognosis. The presence of MSI and LOH in the smoldering and chronic forms of ATL were demonstrated for the first time in this study.
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Ocon, Erika. "Das Tumorsuppressorgen p16/INK4a in epithelialen Ovarialkarzinomen eine Mutations-, Expressions- und Methylierungsanalyse /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972278826.
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Helmrich, Anne. "Genomweite molekular-zytogenetische Charakterisierung INK4A/ARF-defizienter Mauslymphome und Untersuchungen zur evolutionären Konservierung von Common Fragile Sites." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1127319719936-91007.
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Im ersten Teil dieser Arbeit wurden mittels molekular-zytogenetischer Methoden die chromosomalen Aberrationen in c-myc aktivierten ARFnull- und INK4a/ARFnull-Mauslymphomen untersucht. Die zytogenetischen Ergebnisse wurden mit dem Therapieverlauf der Mäuse nach Cyclophosphamid-Behandlung verglichen. In den ARFnull-Lymphomen erkannten wir den Gewinn des Chromosoms 14 als einen Marker für gute und den Gewinn des Chromosoms 6 als Marker für schlechte Behandlungserfolge. Auf den Chromosomen 6 und 14 der Maus liegen demnach bisher unbekannte Gene, welche für die Wahl der Behandlungsmethode ARF-defizienter Tumore von entscheidender Bedeutung sind. Der zweite Teil der Arbeit befaßt sich mit Common Fragile Sites (CFS), die als "hot spots" für chromosomale Brüche und Umbauten in Tumorgenese und Karyotypevolution diskutiert werden. CFSs treten als seltene Lücken im Chromatin oder als partiell deletierte bzw. rearrangierte Chromosomen auf. Ihre Zahl wird durch Zugabe von Replikations-hemmenden Chemikalen, wie Aphidicolin (APC), erheblich gesteigert. Wir untersuchten die CFS-Expression in Lymphozytenkulturen der Mausstämme BALB/c und C57BL/6. Die APC-induzierten CFS-Häufigkeiten der Chromosomenbanden wiesen im Vergleich zwischen beiden Mausstämmen eine signifikante Korrelation und damit eine starke Konservierung auf. Ebenfalls wurde zwischen Maus / Mensch-syntenischen Bereichen eine Konservierung der CFS-Häufigkeiten detektiert. Die Tendenz zur CFS-Bildung ist also ein spezifisches Merkmal jedes chromosomalen Abschnitts, das evolutionär konserviert ist. Weiterhin wurden einzelne CFSs mit molekular-zytogenetischen Methoden genauer kartiert. Auf diese Weise beschrieben wir erstmals eines der zehn häufigsten CFSs menschlicher Lymphozyten, FRA7K, und erweiterten somit die Anzahl molekular charakterisierter humaner CFSs auf insgesamt 13. Für fünf dieser CFSs analysierten wir mittels FISH-Analyse die homologen Bereiche im Mausgenom hinsichtlich ihrer CFS-Expression. Die beobachteten Läsionen traten jeweils in exakt den entsprechenden Sequenzen auf. Vereint man diese fünf Beispiele (FRA2G/Fra2D, FRA7G/Fra6A3.1, FRA7H/Fra6B1, FRA7K/Fra12C1 und FRA9E/Fra4C2) mit bekannten Homologen aus der Literatur, so wurde für insgesamt acht CFSs eine Konservierung zwischen Mensch und Maus auf molekularer Ebene gefunden. Trotz zahlreicher Untersuchungen ist der zelluläre Mechanismus, der die Ausbildung von CFSs an spezifischen Stellen des Genoms bewirkt, bis heute weitgehend unklar. Bekannt ist, daß CFSs durch Replikationsinhibition induziert werden und in Metaphase-Zellen sichtbar werden, welche DNA-Replikations-Checkpoints unterlaufen haben.Sämtliche jüngeren Studien beschrieben Inseln erhöhter DNA-Helix-Flexibilität (Schwankungen im Biegungswinkel des Moleküls) in den Bereichen von CFSs. Wir berechneten die DNA-Helix-Flexibilität entlang der Sequenz für alle molekular kartierten humanen und Maus-CFSs sowie für stabile Kontrollregionen. Anders als in der Literatur beschrieben, fanden wir für Mensch und Maus, daß sich CFSs und Kontroll-DNAAbschnitte in ihrer Dichte an Inseln mit erhöhter DNA-Helix-Flexibilität nicht unterschieden. Nahezu alle Regionen der häufigen molekular charakterisierten CFSs umfassen große Gene, deren Exons mehr als 650 kb genomische Sequenz überspannen. Im Gegensatz dazu traten große Gene in den stabilen Kontrollregionen deutlich seltener auf. Öffentlich zugängliche RNA-Expressionsdaten dieser Gene zeigten, daß CFSs bevorzugt in Bereichen mit transkriptionell aktiven, großen Genen entstehen. Darauf und auf dem Wissen aus der Literatur begründen wir die Hypothese, daß eine Blockierung der DNAReplikationsgabel, vor allem in Bereichen großer transkriptionell aktiver Gene - eventuell begründet durch deren offenere Chromatinstruktur - und das anschließende Unterlaufen von Zellzyklus-Checkpoints an der Bildung von CFSs und damit in einem Anstieg von Doppelstrangbrüchen beteiligt sind.
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Schelwies, Katharina. "Prognostische Bedeutung des p53/Bax/p16 INK4a -Signalwegs bei Patienten mit kolorektalem Karzinom." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2005. http://dx.doi.org/10.18452/15199.
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Die Dysregulation von Zelltod-Signalwegen und die Inaktivierung von Apoptose-Signalwegen ist ein häufiges Ereignis bei der Entstehung maligner Tumore. Ziel dieser dieser Studie war es den prognostischen Wert der Bax- und p16INK4a-Proteinexpression in Korrelation zum Mutationsstatus des p53-Gens bei Patienten in einem Kollektiv von primären kolorektalen Adenokarzinom zu analysieren. Methoden: Retrospektiv wurden 116 Patienten mit einem kolorektalen Karzinom (CRC) im Stadium III und IV nach operativer Therapie und follow-up über 5 Jahre untersucht (UICC Stadium III: 59 Patienten; UICC Stadium IV: 57 Patienten). Die Profile der Bax- und p16INK4a-Proteinexpression wurden mittels Immunhistochemie, die p53-Mutationen (Exon 5 - 8) mittels Single Strand Conformation Polymorphism (SSCP)-PCR untersucht. Die gewonnenen Daten wurden mit klinisch-pathologischen Daten korreliert und statistisch analysiert Ergebnisse: Das mediane Gesamtüberleben betrug 17 Monate. Patienten im Stadium III lebten länger als solche im Stadium IV: 69 vs. acht Monate (pDeregulation of cell death and cell cycle regulation pathways is a frequent event in cancer. Therefore, the purpose of this study was to analyse the prognostic value of Bax and p16INK4a protein expression in correlation to the mutational status of the p53 tumorsuppressor gene in primary colorectal adenocarcinoma. Methods: 116 patients with colorectal adenocarcinoma (CRC) undergoing surgery with curative intention a followed-up for a minimum of five years were analyzed (UICC Stage III: 59 patients, UICC Stage IV: 57 patients). Protein expression profiles of Bax and p16INK4a were analysed by immunhistochemistry, the p53-mutations (exon 5 - 8) by Single-Strand-Conformation-Polymorphism (SSCP)-PCR. Data was correltated with clinical and pathological parameters and analysed statistically. Results: Overall median survival was 17 months. As expected, patients with stage III malignancies survived longer than stage IV patients: 69 months vs. 8 months (p
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Tevelev, Anton. "Investigation of interactions between tumour suppressor p16(INK4A) and cyclin-dependent kinase 4 /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487943610783677.
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Soufir, Nadem. "Locus ink4a - arf : implication dans la predisposition au melanome familial et dans la carcinogenese cutanee." Paris 6, 2000. http://www.theses.fr/2000PA066561.
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Le locus ink4a-arf, situe sur le chromosome 9p21, possede une organisation unique lui permettant de controler efficacement le cycle cellulaire. Il code pour 2 transcrits ; (a) p16 i n k 4 a, gene suppresseur de tumeur appartenant a la famille des inhibiteurs de kinases dependantes des cyclines (cdk), qui agit lors de la phase de transition g1-s en regulant negativement l'activite du complexe cycline d1-cdk4 ; (b) le second transcrit alternatif, p14 a r f, fait partie integrante d'une autre voie de signalisation. Il est induit en reponse a de nombreux oncogenes (e2f1, c-myc, ras, v-abl, e1a), et permet la stabilisation de la proteine p53 en inhibant son exportation hors du noyau, et sa degradation par ubiquitinylation induite par mdm2. Dans la premiere partie de ce travail, nous avons etudie l'implication de p16 i n k 4 a et de cdk4 dans la predisposition hereditaire au melanome familial, cutane puis ophtalmique. Nous avons mis en evidence l'un des plus fort taux de mutations du gene p16 i n k 4 a rapporte dans la litterature (44%), ainsi qu'une seconde mutation germinale de cdk4, confirmant le role important joue par ces genes dans la predisposition au melanome familial cutane. Les mutations germinales de p16 i n k 4 a semblent plus frequentes dans les familles avec 3 cas ou plus de melanome, ou comprenant un cas de melanome multiple primitif. En revanche, ces 2 genes ne semblent pas impliques dans la predisposition hereditaire au melanome ophtalmique, confirmant l'heterogeneite genetique du melanome familial. Dans une seconde partie, nous avons etudie l'implication du locus ink4a-arf, parallelement avec celle du gene p53, dans l'oncogenese des carcinomes cutanes (carcinomes basocellulaires et spinocellulaires) sporadiques, et provenant de malades atteints de xeroderma pigmentosum (xp). Nous avons montre la presence de mutations de p16 i n k 4 a caracteristiques uv induites dans 12% des carcinomes sporadiques, et 28% des carcinomes de malades xp. Ces mutations avaient pour la majorite un effet potentiel sur p14 a r f, affectant soit un residu conserve, soit localise dans un domaine fonctionnel important de la proteine. Dans les tumeurs des malades xp, on retrouvait frequemment la presence simultanee de mutations de p53 et ink4a-arf, refletant l'hypermutabilite des cellules de ces malades. Nos resultats montrent donc que l'inactivation du locus ink4a-arf joue un role important dans l'oncogenese des carcinomes cutanes, et s'inscrit dans le processus de carcinogenese multi-etapes de ces tumeurs.
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Maciejewska, Zuzanna. "Roles of the multifunctional protein E4F1 in cellular senescence." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20245/document.
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Le facteur de transcription E4F1 fût initialement identifié comme une cible cellulaire de l'oncoprotéine virale E1A au cours de l'infection par l'adénovirus sérotype V. E4F1 est une protéine multifonctionelle essentielle au cours du développement embryonnaire précoce et joue des rôles importants dans l'équilibre entre prolifération/survie de différents types cellulaires, notamment des cellules souches. Au niveau moléculaire, E4F1 possède des activités transcriptionelles intrinsèques mais possède également une activité ubiquitine E3 ligase atypique dirigée contre d'autres facteurs de transcription tel que le suppresseur de tumeur p53. Récemment, il a été démontré qu'E4F1 régule les voies oncogéniques impliquant p53 et Rb qui jouent un rôle essentiel au cours de la sénescence cellulaire. La sénescence, qui est définie par un arrêt irréversible du cycle cellulaire, est considéré comme un mécanisme suppresseur de tumeurs essentiel au cours des phases précoces du développement tumoral. L'objectif de ma thèse a été d'évaluer le rôle d'E4F1 au cours de la sénescence cellulaire. Au travers d'études menées sur des fibroblastes humains primaires et des fibroblastes embryonnaires murins dérivés de souris génétiquement modifiées pour le gène E4F1, j'ai examiné comment la perturbation des activités d'E4F1 module l'initiation ou le maintien de la sénescence prématurée induit par l'oncogène RAS, la déplétion du membre de la famille polycomb Bmi1, ou par les dommages à l'ADN. Mes résultats suggèrent que la déplétion d'E4F1 protège partiellement contre l'induction de la sénescence alors que l'expression ectopique d'E4F1 accélère la sénescence par son implication dans la voie INK4A/ARF-p53. L'ensemble de mes résultats supportent la notion qu'E4F1 est un régulateur important de la sénescence cellulaireE4F1 was originally identified as a cellular target of the viral oncoprotein E1A during adenoviral infection. E4F1 is a multifunctional protein that is essential during early embryogenesis and plays important roles in the proliferation/survival balance of different cell types including stem cells. At the molecular level, E4F1 exhibits intrinsic transcriptional activities but also an ubiquitin E3 ligase function that targets other transcription factors, including the p53 tumor suppressor. Recent studies indicate that E4F1 impinge on several pathways, including the Rb and p53 pathways, that are known to influence cellular senescence, an irreversible state of cell cycle arrest that is considered to be an essential tumor suppressor mechanism during early steps of tumorigenesis. The objective of my thesis was to evaluate the roles of E4F1 during cellular senescence. Using human primary fibroblasts and mouse embryonic fibroblasts derived from genetic ally engineered mouse models, I investigated how perturbations of E4F1 activities modulated the initiation or the maintenance of premature senescence induced by oncogenic Ras, depletion of the polycomb member Bmi1 or DNA damage. My results suggest that E4F1 depletion partly protects from the induction of cellular senescence whereas ectopic expression of E4F1 accelerates premature senescence through its implication in the Ink4a/ARF-p53 pathway. Altogether, my results support the notion that E4F1 is an important regulator of cellular senescence
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Nicholls, James Ronald. "Investigating protein complexes that are involved in the function and regulation of the human INK4a/ARF locus." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1444889/.
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A common mechanism used by cancer cells to over-ride normal restraints on cellular proliferation is abrogation of the tumour suppressive functions of the INK4a/ARF locus. This can be achieved either through genetic changes to the locus or by dysregulation of the molecular pathways that operate to mediate its function or transcriptional regulation. The INK4a/ARF locus encodes two structurally unrelated proteins which have a common exon translated in alternative reading frames. These proteins are named p16INK4a and p14ARF and they both have antiproliferative effects mediated by the Rb and p53 pathways respectively. In this thesis, proteomic approaches have been used to map out some of the protein-protein interaction networks that are involved in function or regulation of INK4a/ARF. Multiprotein complexes are involved both in function (D cyclin-Cdk) and regulation (Cbx7) of the locus and a major focus of this work has been the determination of their molecular composition. The main findings of this thesis relate to the protein-protein interactions of Cbx7, a known transcriptional repressor of INK4A/ARF, which has been implicated as an oncogene. In an analogous manner to other members of the Polycomb group (PcG) of proteins, it was found to participate in a large multiprotein complex. Constituents of a Cbx7 complex isolated from human cells were identified by mass spectrometry. Analysis revealed that it was made up of a subset of the known human PcG proteins and some novel interacting proteins, including an RNA helicase, which had not previously been reported in PcG complexes. The specificity of these interactions was then validated by other biochemical methods. The impact of some of these interactions on the repressive function of Cbx7 has been evaluated in primary human fibroblasts, with a view to understanding how the complex silences transcription.
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Stott, Francesca Joanne. "Analysis of the INK4 family of cyclin dependent kinase inhibitors, in the mammalian cell cycle." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322001.
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Gendre-Gilles, Laure. "Régulation de l'arrêt des endomitoses et de la différenciation mégacaryocytaire terminale : rôle de p19 INK4D et de MAL." Paris 7, 2009. http://www.theses.fr/2009PA077075.
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La mégacaryopoïèse est le système de production et de régulation de la production des plaquettes et se divise en trois étapes: étape pendant laquelle les cellules font des mitoses, polyploïdisation par endomitose, libération des plaquettes par fragmentation du cytoplasme. Le travail de ma thèse a concerné la mégacaryopoïèse à travers l'étude de 2 protéines : MAL et p19INK4D (p19). MAL qui est le cofacteur transcriptionnel de SRF est aussi impliqué dans une translocation retrouvée dans les leucémies aiguës à mégacaryoblastes. Nous avons montré que son expression augmente avec la différenciation mégacaryocytaire et qu'en son absence, l'organisation du cytosquelette est fortement perturbée. Dans ces conditions, la migration et la formation des proplaquettes sont inhibées. Deux gènes présentent une expression fortement diminuée en l'absence de MAL dans les mégacaryocytes (MK), MMP-9 et MYL-9. Ces 2 gènes sont directement régulés par le complexe transcriptionnel MAL/SRF. Le défaut de migration que nous avons mis en évidence pourrait être lié à la diminution de MMP-9. Nous avons enfin montré qu'un défaut quantitatif de MYL-9 altère la formation des proplaquettes. Le seul inhibiteur du cycle cellulaire dont l'expression augmente linéairement avec la ploïdie est p19. Nous avons montré que cette protéine constitue un lien entre l'arrêt des endomitoses et la différenciation terminale des MK. Ces résultats ont été confirmés par l'étude des souris p79⁻⁄⁻A chez qui la ploïdie modale des MK est fortement augmentée. Enfin, l'expression de p19 est régulée par le facteur de transcription hématopoïétique AML-1, impliqué à différents niveaux de l'hématopoïèseMegakaryopoiesis is the System of platelet production divided in three steps: mitosis step, increase in ploidy level by endomitosis, platelet sheeding by cytoplasm fragmentation. My work focused on megakaryopoiesis through the study of two proteins: MAL and p19INK4D (p19). MAL is a transcriptional co-activator of SRF. In acute megakaryoblastic leukemia, thé MAL gene is translocated and fused with the gene encoding OTT. We showed that MAL expression increases during the megakaryocyte (MK) differentiation. MAL knockdown in MK progenitors reduced the percentage of cells forming filopodia, lamellipodia and stress fibers, and reduced proplatelet formation. MAL repression led to dysmorphic MK with disorganized demarcation membranes and alpha granules heterogeneously scattered in the cytoplasm. Gene expression profiling revealed a decrease in MMP9 and MYL9 expression after MAL inhibition. Chromatin immunoprecipitation in MK showed that the MAL/SRF complex directly regulates MYL9 and MMP9. MK migration was considerably decreased after MAL knock down, implicating MMP9 in migration. Finally, the use of a shRNA to decrease MYL9 expression showed that MYL9 was involved in proplatelet formation. P19 expression was increased during ploidization. We showed that p19 knockdown led to an increase in the mean ploidy of human MKs. This increase in ploidy was associated with a decrease in the more mature MKpopulation. Inversely, p19 overexpression resulted in a decrease in mean ploidy level. Confirming these results, bone marrow MKs from p19 KO mice exhibited an increase in mean ploidy level. Finally we showed that p19 is directly regulated by the hematopoietic transcription factor AML1
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Sandmann, Vanessa [Verfasser]. "Untersuchung des Zusammenhanges von Malignomen der Glandula parotis, Humanen Papillomviren und der Überexpression des Proteins p16 ink4a / Vanessa Sandmann." Köln : Deutsche Zentralbibliothek für Medizin, 2018. http://d-nb.info/1170170099/34.
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Hayes, Michelle. "Investigation and characterisation of cell lines containing a deletion in the INK4a locus under normal and pro-apoptotic conditions." Thesis, University of Sussex, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272056.
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Güner, Dilek. "Deregulation von Zellzyklus und Apoptose beim Plattenepithelkarzinom des Ösophagus." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2003. http://dx.doi.org/10.18452/14953.
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Störung des G1-Restriktionspunkts des Zellzyklus und Verlust der Wachstumskontrolle in Folge der Inaktivierung des Rb-Signalwegs ist ein häufiges Ereignis in malignen Tumoren. Gemeinsam mit der Hemmung von Apoptose-Signalwegen sind solche genetischen Ereignisse zentrale pathogenetische Faktoren der Tumorentstehung. Diese Veränderungen prägen aber auch entscheidend die Tumorbiologie und bestimmen somit intrinische und erworbene Therapieresistenz und konsequenterweise auch die klinische Prognose der Tumorerkrankung. In der vorliegenden Arbeit wurden Veränderungen im Rb- und im p53-Signalweg in Plattenepithelkarzinomen des Ösophagus untersucht. Diese retrospektive Studie wurde an Tumorproben von 53 mit kurativer Intention R0-resezierten Patienten durchgeführt. Proteinexpression wurde mittels Immunhistochemie und Mutationen mittels SSCP-PCR analysiert. Aktivierende Punktmutationen des K-ras Onkogens wurden mittels mutationsselektiver genomischer PCR und eines sequenzspezifischen Festphasen-Hybridisierungstests nachgewiesen. Die Analyse der individuellen Gene zeigte, dass Expressionsverlust der Rb-Signalwegskomponenten p16INK4a, p21CIP/WAF-1, p27KIP1 und von Rb selbst, sowie die Überexpression von Cyclin D1 bzw. Verlust des pro-apoptotischen Bcl-2 Homologs Bax mit schlechter Prognose, d.h. kürzerem Überleben korrelierte. Überexpression von Cyclin E, p53 oder Bcl-2, sowie Mutation von p53 bzw. K-ras zeigten hingegen keinen Einfluss auf die Prognose. Das längste Überleben wurde in einer Subgruppe von Patienten beobachtet deren Tumore eine Kombination günstiger Genotypen zeigte, und zwar niedrige Cyclin D1 Expression, sowie hohe Expression von Rb, p21CIP/WAF-1, p16INK4a und Bax. Diese Ergebnisse zeigen, dass eine Multigen- oder "Multimarker"-Analyse von Genen, die konsekutiv oder synergistisch in Zellzyklus- und Apoptose-Signalwegen agieren, zur Prognoseabschätzung der Analyse individueller Gene deutlich überlegen ist. Die Identifikation solcher genetischer Markerprofile sollte sich auch zukünftig als nützlich für die klinische Entscheidungsfindung in der Therapie maligner Tumore erweisen und wird konventionelle klinische und pathologische Faktoren komplementieren, die bisher keine ausreichende Prognoseabschätzung erlauben.Malignant tumors frequently show inactivation of the Rb pathway and, as a result, deregulation of the G1 restriction point of the cell cycle and loss of growth control. Together with the inhibition of apoptosis signaling pathways, such events are key pathogenetic factors in tumor development. Moreover, these aberrations are decisive in determining tumor biology and characteristics such as intrinisic or acquired resistance to therapy and, consequently, the clinical prognosis of the malignant disease. In the present work, aberrations in the Rb and the p53 pathway were analysed. This retrospective study was undertaken in a cohort of 53 patients with esophageal squamous cell carcinoma who underwent R0 resection with a curative intent. Protein expression in tumor samples was analysed by means of immunohistochemistry and mutations were investigated by the use of genomic SSCP-PCR. Activating point mutations of the K-ras oncogene were detected by the use of mutation-selective genomic PCR and a sequence specific solid phase hybridization assay. The analysis of individual genes showed a correlation between poor prognosis, i.e. short overall survival, and loss of the Rb pathway components p16INK4a, p21CIP/WAF-1, p27KIP1, and Rb itself, or overexpression of cyclin D1 or loss of the pro-apoptotic Bcl-2 homolog Bax. In contrast, overexpression of cyclin E, p53 or Bcl-2 and mutation of p53 or K-ras had no influence on disease prognosis. The longest survival was found in a subgroup of patients whose tumors exhibited a combination of favorable genotypes, i.e. low expression of cyclin D1, and high expression of Rb, p21CIP/WAF-1, p16INK4a and Bax. These results demonstrate that a multigene or "multimarker"-analysis of genes that act consecutively or synergistically in cell cycle and apoptosis signaling pathways is far superior to determine disease prognosis when compared to the analysis of individual genes. The identification of such genetic marker profiles should proove beneficial in clinical decision making in the therapy of malignant tumors. In the future, such diagnostic tools may be useful to complement conventional clinical and pathologic factors which in most instances do not allow prediction of disease prognosis.
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Schelwies, Katharina [Verfasser], P. [Gutachter] Daniel, R. [Gutachter] Greil, and S. [Gutachter] Wesselborg. "Prognostische Bedeutung des p53/Bax/p16 INK4a -Signalwegs bei Patienten mit kolorektalem Karzinom / Katharina Schelwies ; Gutachter: P. Daniel, R. Greil, S. Wesselborg." Berlin : Humboldt-Universität zu Berlin, 2005. http://d-nb.info/1207629987/34.
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Eshraghi, Parisa [Verfasser]. "p18 (Ink4c) deletion prolongs lifespan of telomere dysfunctional mice by improving stem cell self-renewal independent of DNA damage checkpoint activation / Parisa Eshraghi." Ulm : Universität Ulm. Fakultät für Naturwissenschaften, 2012. http://d-nb.info/1024931234/34.
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Bastos, Joana Fróes Bragança 1971. "Expressão do 'p16 POT. INK4a' e do p53 como marcadores prognosticos da neoplasia intra-epitelial cervical e sua relação com o papilomavirus humano de alto risco oncogenico." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312148.
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Orientadores: Sophie Françoise Mauricette Derchain, Luis Otavio Zanatta SarianTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-08T23:10:57Z (GMT). No. of bitstreams: 1 Bastos_JoanaFroesBraganca_D.pdf: 1852084 bytes, checksum: 0197c5b05094e118039dc4b6c6ffbf73 (MD5) Previous issue date: 2007
Resumo: Objetivo: Avaliar a relação da expressão do p53 e do p16INK4a em diferentes graus de neoplasia intra-epitelial cervical (NIC) e suas possíveis relações com a recidiva/persistência da NIC após conização diatérmica e a infecção persistente de papilomavírus humano (HPV) de alto risco oncogênico. Sujeitos e métodos: Este foi um estudo de corte, com análise intermediária em corte transversal, para o qual foram selecionadas mulheres submetidas à conização diatérmica no período de fevereiro de 2001 a abril de 2004. Os resultados deste estudo são apresentados em dois artigos: o primeiro consiste em corte transversal incluindo 125 espécimes cirúrgicos de mulheres submetidas a conização diatérmica. Foram avaliadas a expressão do p53 e do p16INK4a em diferentes graus de NIC e sua relação com a infecção pelo HPV de alto risco oncogênico realizado através da Captura de Híbridos 2 (CH2). No segundo artigo, com análise longitudinal foram incluídas 104 mulheres com NIC 2 ou 3, seguidas por até 24 meses após conização diatérmica. Foram avaliadas a expressão de p16INK4a e p53 como fatores préditivos de persistência/recidiva de NIC e a sua relação com a infecção persistente por HPV de alto risco oncogênico após o conização cervical diatérmica. Resultados: No primeiro artigo foram incluídos 21 casos cervicites/NIC1, 17 NIC2 e 87 NIC3. Noventa e nove (79,2%) casos foram positivos para p16INK4a (> 5% do epitélio corado), significativamente maior em lesões de alto grau (p< 0.001). A expressão do p53 não variou de acordo com o grau histológico. Não houve correlação entre a expressão da p16INK4a e a detecção do HPV de alto risco oncogênico. A expressão do p16INK4a não teve relação com a do p53. No segundo artigo, 104 mulheres com NIC 2 ou 3 foram acompanhadas por 24 meses, e detectou-se 12 casos de recidiva/persistência de NIC, sendo 8 nos primeiros 6 meses. Entre as mulheres com recidiva/persistência de NIC, 9 (75%) apresentaram presistência do HPV de alto risco oncogênico. A expressão da p16INK4a foi moderada/forte em 96 casos (92%) e mais de 50% dos núcleos estavam corados para p53 em 80 (78%). A análise prospectiva não detectou diferença significativa na recidiva/persistência da NIC durante o follow up com segundo a expressão do p16INK4a ou do p53. Nenhum dos parametros estudados teve relação com a infecção persistente pelo HPV. Conclusões: este estudo está em concordância com o conhecimento atual e mostra uma associação da positividade para p16INK4a com a severidade da lesão cervical, embora esta proteína não esteja associada com a detecção de HPV de alto risco oncogênico pela CH2. Não houve correlação entre a expressão de p53 e a positividade para HPV nem houve associação da expressão do p53 com a do p16INK4a. A análise prospectiva não mostrou correlação entre a expressão do p 16 INK4a e do p53 e a recorrência/persistência da NIC ou persistência do HPV de alto risco oncogênico no seguimento de mulheres com NIC 2 ou 3 tratadas com conização diatérmica
Abstract: Objective: to concurrently investigate the immunoexpression of p53 and p16INK4a4 in different grades of cervical intra-epithelial neoplasia (CIN) and their relation with the persistence/ recurrence of CIN and persistent infection by high-risk Human Papillomavirus (hr-HPV) after electrosurgical cervical conization. Subject and methods: a series of 125 women subjected to electrosurgical conization was selected for this cross-sectional and cohort study. Enrollment was carried out between February 2001 and April 2004. The results of this study are presented in two articles: the first one consists of a cross-sectional analisys, including 125 surgical specimens of women who underwent diathermic conization. Expression of p53 and p16INK4a were evaluated in different grades of CIN and their relation with hr-HPV infection was evaluated with HC2. The second article is a longitudinal analysis on 104 women with CIN 2 and 3, followed up for 24 months after electrosurgical cervical conization. Expression of p16INK4a and p53 were tested as predictive markers of persistent/recurrent CIN and persistent infection by hr-HPV during follow up after electrosurgical cervical conization. Results: in the first series, 21 cases of CIN1, 17 CIN2 and 87 CIN3 were included. Ninety-nine (79.2%) cases stained moderate/strongly to p16INK4a, significantly higher in high-grade CIN (p< 0.001). p53 expression did not relate with the grade of CIN and there was no relation between p16INK4a expression and hr-HPV detection. Expression p16INK4a and p53 were not correlated. In the second article, 104 women with CIN 2 or 3 were followed up for 24 months, and 12 (11%) persistent/recurrent CIN were observed, eight of them during the first 6 months follow-up. Among women with persistent/recurrent CIN, 9 (75%) presented persistent hr-HPV detection. p16INK4a expression was moderate/strong in 96 cases (92%) and p53 stained in more than 50% of the nuclei in 80 (77%). The expression of p16INK4a or p53 was not associated with persistent/recurrent CIN during follow-up. None of the studied parameters correlated with persistent hr-HPV detection. Conclusion: these results showed a strong association between p16INK4a expression and grade of CIN, although this protein was not associated with hr-HPV detection by HC2. There was no relation between p53 and hr-HPV detection or p16INK4a expression. Prospective analysis showed that p16INK4a and p53 expression was not related with persistent/recurrent CIN or persistent hr- HPV detection during follow-up of women conservatively treated for CIN 2 or 3
Doutorado
Tocoginecologia
Doutor em Tocoginecologia
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Fonseca, Fernanda Villar. "O papel do imunomarcador P16(INK4A) no manejo da neoplasia intraepitelial cervical de alto grau, seu risco de recorrência e a associação com a tipagem de HPV." reponame:Repositório Institucional da UFPR, 2016. http://hdl.handle.net/1884/45281.
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Orientador: Prof. Dr. Newton Sérgio de CarvalhoOrientador: Profª. Drª. Teresa C. Cavalcante
Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Programa de Pós-Graduação em Medicina Interna. Defesa : Curitiba, 12/08/2016
Inclui referências : f. 57-64;72-74;82-84;95-97
Resumo: Introdução: Avaliar a expressão do biomarcador p16INK4a no produto de conização de mulheres com diagnóstico de NIC-AG e correlacionar a sua expressão com a severidade das lesões, a habilidade de prever a recorrência, as diferenças biológicas entre NIC 2 e 3 e a tipagem de HPV. Método: um estudo transversal, conduzido em pacientes que foram submetidas a conização por NIC-AG, com DNA-HPV previamente conhecido, entre janeiro 2009 e agosto 2011, no Hospital Erasto Gaertner/ Brasil. A pesquisa do p16 foi avaliada por meio da técnica de microarranjos teciduais e sua expressão correlacionada com o diagnóstico clínico, índice de recorrência e as diferenças biológicas entre NIC 2 e 3. O teste do X2 foi usado para análise estatística com valor de p?0.05, e a sensibilidade, especificidade, VPP, VPN e acurária dos testes calculadas. Resultados: 192 mulheres, entre 22 e 48 anos (35 ± 6), divididas em 2 grupos: 102 NIC 2 e 90 NIC 3. A média de idade, paridade, hábito de fumar e técnica de conização foi semelhantes nos 2 grupos. O p16 foi positivo em 86% dos NIC 2 e 92% dos NIC 3. Em relação a recorrência o p16 teve VPP de 11%, VPN de 95%, sensibilidade de 95%, especificidade de11% e acurácia de 93%. A habilidade do p16 em predizer as diferenças entre NIC 2 e 3 resultou em VPP de 48% e VPN de 66%, sensibilidade de 92%, especificidade de 13% e acurácia de 89%. Conclusão: A expressão do p16 isoladamente não foi capaz de predizer a recorrência da NIC-AG tratada e nem de demonstrar as diferenças biológicas entre NIC 2 e 3, entretanto sua expressão se relaciona diretamente com a severidade da doença. Palavras-chaves: Neoplasia intraepitelial cervical, recorrência, marcadores biológicos, NIC-AG.
Abstract: Background: The aim of this study is to evaluate the expression of biomarker p16INK4a on the product of conization in women diagnosed with HSIL, to correlate immunostaining with lesion severity, the ability to predict recurrence and the biological differences between CIN 2 and CIN 3. Methods: A cross-sectional study was conducted in patients who had undergone conization due to HSIL and detected HPV DNA, at Erasto Gaertner Cancer Center (EGCC) Hospital, in Brazil. The expression of p16INK4a was evaluated using tissue microarray technique and overexpression was correlated to diagnosis and clinical evolution. A chi-square test was used for statistical analysis with p-value less than or equal to 0.05 and the sensitivity, specificity, PPV, NPV, and accuracy of the tests calculated. Results: The review included 192 women, between 22 and 48 years old (35 ± 6), divided into two groups: 102 CIN 2 and 90 CIN 3 cases. The epidemiological data were similar in the two groups. p16 was positive in 86% of the CIN 2 and 92% of CIN 3. To predict recurrence p16 has PPV of 11%, NPV of 95%, sensitivity of 95%, specificity of 11%, and accuracy 93%. Applied to distinguish between CIN 2 and 3 p16 has VPP of 48%, VPN of 66%, sensitivity of 92%, specificity of 13%, and accuracy 89%. Conclusion: Immunostaging of biomarker p16 alone cannot predict the rate of recurrence of HSIL or can it demonstrate the biological differences between CIN 2 and 3; however, overexpression does increase with the degree of lesion severity. Key words: Cervical intraepithelial neoplasia, recurrence, biological biomarkers, HSIL
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Poi, Ming. "Low-barrier hydrogen bonding in bovine pancreatic Phospholipase A₂ and somatic INK4A-ARF locus mutations : a significant mechanism of gene inactivation in head and neck squamous cell carcinomas /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486402544589967.
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Calil, Luciane Noal. "Expressão imuno-histoquímica de P16 INK4A, K167 e receptores de estrogênio e progesterona em lesões do colo uterino, sua associação com infecção pelo papilomavirus humano e seus correlatos epidemiológicos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/12952.
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Introdução: Estudos epidemiológicos demonstram que cerca de 99,0% dos carcinomas cervicais estão associados à infecção persistente por alguns tipos de Papilomavírus Humano (HPV). O longo período de latência a partir da infecção primária e o aparecimento de lesões sugerem que fatores adicionais, como início precoce das relações sexuais, número de parceiros, tabagismo, uso de hormônios, presença de co-infecções, estejam envolvidos no processo de carcinogênese. A co-infecção por Chlamydia trachomatis (CT) tem sido sugerida, como um fator contribuinte na patologia cervical. A detecção precoce das lesões e o grau histológico são fundamentais, mas às vezes, difícil. O emprego de marcadores prognósticos, através da técnica de imuno-histoquímica possibilita esclarecer e complementar resultados controversos de citologia e de biópsias. Objetivos: Verificar a presença de infecção pelo Papilomavírus humano, tipos de alto risco, a presença de co-infecção por CT, associação com as características epidemiológicas, bem como, identificar a expressão imuno-histoquímica de p16INK4a, Ki67, receptores de estrogênio e progesterona em lesões pré-neoplásicas e neoplásicas de cérvice uterina. Métodos: Um estudo transversal envolvendo mulheres assintomáticas foi desenvolvido entre fevereiro de 2003 e janeiro de 2006 em uma Unidade de Atenção Primária à Saúde em Porto Alegre – RS, Brasil para verificar a prevalência de infecção pelo HPV, tipos -16, -18, -31 e de CT. Um total de 89 participantes respondeu a um questionário epidemiológico padronizado sobre as características demográficas, hábitos pregressos, história reprodutiva e de comportamento sexual. A pesquisa de DNA-HPV, tipos de alto risco, bem como a presença de DNA-CT foi identificada através da técnica da Reação da Polimerase em Cadeia (PCR). Após examecolposcópico, foi coletada biópsia para avaliação imuno-histoquímica empregando os marcadores p16INK4a, Ki67, receptores hormonais de estrogênio e progesterona. RESULTADOS: A presença de DNA-HPV foi identificada em 83,0% (74/89) das biópsias, sendo que 46,0% (34/74) eram portadoras de HPV de alto risco. O DNA-CT foi presente em 16/86 pacientes testadas (19,0%). Quanto ao exame anatomopatológico (AP), 7,0% eram lesões de alto grau, 59,0% de baixo grau e em 34,0% não foram observadas alterações. A expressão de p16INK4a foi observada em 85,3% (29/34) das mulheres positivas para DNA-HPV-AR e esta associação foi estatisticamente significativa (p=0,02), sendo que, todas as biópsias, positivas para HPV-16 (16/34), expressaram a proteína (p=0,01). Houve uma associação estatisticamente significativa entre a intensidade de expressão, o padrão de expressão de p16INK4a e o grau da lesão (p= 0,001). A associação entre a expressão de p16INK4a e DNA-HPV se mostrou estatisticamente significativa entre fumantes (p=0,03; OR: 11,25 IC95%:1,11-114,4), entre mulheres com história prévia de DST (p=0,01; OR: 6,82 IC95% 1,53-30,3), com sexarca entre17-19 anos (p=0,048; OR: 8,500 IC95% 0,971-74,424) e em mulheres com três ou mais parceiros sexuais ao longo da vida (p=0,02; OR: 8,12 IC95%: 1,31-50,2). Todas as mulheres positivas para DNA-CT foram positivas para DNA-HPV. Entre as portadoras de co-infecção, 56,0% expressaram a p16INK4a (OR=0,51, IC95%: 0,17-1,57. Para Ki67, todas as lesões de alto grau, 50,0% das lesões de baixo grau e 31,0% das biópsias negativas expressaram o mesmo (p=0,004). Para as pacientes portadoras de DNA-HPV, o Ki67 foi expresso em 100,0%, 31,0% e 32,0% das lesões de alto grau, baixo grau e fragmentos normais, respectivamente, apresentando uma associação estatisticamente significativa (p<0,003). Não foi observada associação entre a expressão do receptor de estrogênio e os desfechos estudados. Já, o receptor de progesterona foi expresso em 42,0% (37/89) dos casos estudados e, 26,5% (9/37) eram positivas para os tiposvirais de alto risco (p=0,023). A expressão do receptor de progesterona foi maior em nãofumantes (p=0,02), entre as mulheres que utilizavam anticoncepcional oral (p=0,03) e que tinham um menor grau de escolaridade (p=0,04). Discussão e conclusões: A presença da infecção persistente pelo HPV em lesões cervicais nos diferentes graus histológicos é fato já demonstrado. A atividade transformadora do vírus, especialmente com a expressão de oncoproteínas virais, facilita a de replicação e a diferenciação do epitélio após a sua integração no genoma hospedeiro. Desta forma, a identificação dos tipos virais de alto risco é essencial para se estabelecer e avaliar o prognóstico das lesões e a expressão imuno-histoquímica de p16INK4a e Ki67 podem confirmar resultados citológicos suspeitos. A co-infecção por CT, descrita em diversos estudos epidemiológicos, tem sido relatada como um fator de risco para a infecção por HPV, bem como o desenvolvimento de lesões mais agressivas. Entretanto, em nosso estudo, não foi encontrada associação entre os desfechos e a infecção por CT, exceto para pacientes com menor grau de escolaridade, provavelmente, em virtude do pequeno tamanho da amostra. Observa-se, através desta análise, a contribuição da técnica de imuno-histoquímica e de marcadores de oncogenicidade, como a p16INK4a e do Ki67 no diagnóstico das lesões ativas. A associação das variáveis epidemiológicas com estes marcadores se mostrou efetiva, já que existem evidências de que alguns destes podem facilitar e contribuir para o desenvolvimento destas lesões.Introdution: Epidemiological studies have shown that about 99.0% of cervical carcinomas are related to persistent infection caused by some human papillomavirus (HPV) types. The large latency period since primary infection and the appearance of lesion suggests that adicional factors such as age at first intercourse, number of sexual partners, smoking, oral contraceptive use and other factors are involved in the carcinogenesis process. Among this, the co-infection by Chlamydia trachomatis (CT) have been sugested by some authors as a contributor factor in the cervical patology. The precoce detection of lesions and the histological grade are important, but sometimes difficult. The use of prognostic markers through immunohistochemical technic clarify and complement controversial results in citology. Objetives: Verifing the presence of Human papillomavirus infection, high – risk subtypes, the presence of CT co-infection, and the association with the epidemiological factors as well as identifying the immunoistochemical expression of p16INK4a, Ki67, and estrogen and progesterone receptors in pre-neoplastic and neoplastic lesions of uterine cervix. . Materials and methods: A cross-sectinal study with assintomatic women was conducted between february 2003 and december 2006 in a primary care unit in Porto Alegre- RS, Brazil to verify the prevalence of Papillomavirus infection, sub-types -16,18,31 and CT infecttion. The participants answered a questionaire about sociodemographic characteristics, former habits, reproductive history and sexual behaviour.The high-risk DNA-HPV subtypes reserach (HPV - 16,-18,-31) and the presence of DNA-Chlamydia trachomatis (CT) was identified through Polimerase Chain Reation Technique (PCR). After colposcopi examination, was collected biopsy for immunohistochemical analysis of p16INK4a, Ki67, estrogen and progesterone receptors. RESULTS: The DNA-HPV was observed in 83% (74/89) biopsies and 46% (34/74) were highrisk types (16,18,31). DNA-CT was detected in 16/86 patients (19%). In relation to anatomopathological exam, 7% were high-squamous intraepithelial lesion (HSIL), 59% low squamous intraepithelial lesion (LSIL) and in 34% no was observed alterations. The expression of p16INK4a was observed in 85,3% (29/34) positive women to DNA-HPV HR and this association was statistically significant (p=0,02). All biopsies HPV-16 positive (16/34) expressed p16INK4a (p=0,01). There was a significant association between intensity, pattern of expression and grade of lesion (p=0,001). The association between p16INK4a expression and DNA-HPV was statistically significant in smokers (p=0,03; OR: 11,25 IC95%:1,11-114,4), in women with previous history of sexual transmitted disease (SDT) (p=0,01; OR: 6,82 IC95% 1,53-30,3), women withbthe first intercourse between 17-19 years (p=0,048; OR: 8,500 IC95% 0,971- 74,424) and in women with three or more lifetime sexual partners (p=0,02;OR 8,12 IC95%:1,31- 50,2). Women positive to DNA-CT were positive to DNA-HPV. Between women DNA-HPV positive, the antibody Ki67 was expressed in 100%, 31% and 32% of HSIL, LSIL and normal fragments respectively and this association was statisticaly significative (p<0,003). No association was observed between the estrogen receptor expression and the outcomes studied. The progesterone receptor was expressed in 42% of cases studied (37/89), and 26,5% (9/37) was positive for high-risk types (p=0,023). The progesterone receptor expression was greater in nosmokers (p=0,02), between women who use oral contraceptives (p=0,03) and that have lower school-grade (p=0,04). Discussion and conclusion: The presence of HPV persistent infection in cervical lesions in different histological grades is fact already demonstrated. The virus transforming activity is in accordance with its capacity of replication and the diferentiation through epiteliaafter its integration. The identification of high types of virus is essential to establish and evaluate the prognosis of lesions. The co-infection with CT described in several epidemiological studies has been related as a risk factor to acquire the HPV infection and to develop more agressive lesions. Howevwer in our study except in relation to lower school grade no association was observed between the outcomes and the co-infection by CT, probably due to the small sample. It observed trough this study, the contribution of the immunohistochemical analysis of concogenic markers suh as p16INK4a and Ki67 expression in the diagnostic and follow-up of active lesions. The associaton of epidemiological variables with these markers showed efficient, and evidence existe that some variables can contribute to lesions transformation.
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Victor, Pedro Sousa. "Skeletal muscle aging: stem cell function and tissue homeostasis." Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/81933.
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Muscle aging, in particular, is characterized by the reduction of tissue mass and function, which are particularly prominent in geriatric individuals undergoing sarcopenia. The age-associated muscle wasting is also associated with a decline in regenerative ability and a reduction in resident muscle stem cell (satellite cell) number and function. Although sarcopenia is one of the major contributors to the general loss of physiological function, the mechanisms involved in age-related loss of muscle homeostasis and satellite cell activity are yet poorly understood.
Using a microarray-based transcriptome analysis of muscle stem cells isolated from young and physiologically aged/geriatric mice, we uncovered specific changes in the gene expression profile that highlighted key biological processes and potential molecular markers associated with satellite cell aging, which included p16INK4a. We used Bmi1-deficient mice to further explore the implications of p16INK4a up-regulation in satellite cell function. We found premature p16INK4a up-regulation in young/adult Bmi1-deficient satellite cells correlating with defects in satellite cell number, proliferation and self-renewal capacity. In addition we have identified a number of overlapping biological processes dysregulated in physiologically aged and Bmi1-deficient satellite cells, suggesting that Bmi1-dependent epigenetic regulation may underlie many of the intrinsic changes taking place in chronologically aged satellite cells. In addition, we show that Bmi1 loss causes defects of late postnatal/adult muscle growth characterized by reduced muscle mass with smaller muscle fibers, typical of atrophying senescent/sarcopenic muscle. Since p16INK4a expression is specifically up-regulated in muscle satellite cells of geriatric, sarcopenic mice and in a mouse model of accelerated senescence/sarcopenia (SAMP8), we propose that the Bmi1/p16INK4a axis might be particularly operative in muscle stem cells from the elderly.
Muscle wasting is one of the physiological consequences of sarcopenia and the identification of novel factors regulating muscle growth and atrophy is of potential relevance for therapeutical applications. We have uncovered a new role for Sestrins as skeletal muscle growth promoting factors in the adult. We found Sestrins expression regulated in mouse models of skeletal muscle atrophy and hypertrophy and in human myopathies. Through a gain of function approach we show that Sestrins induce skeletal muscle growth, by activating the IGF1/PI3K/AKT pathway.El envejecimiento del tejido muscular está caracterizado concretamente por una reducción global de la masa muscular y un empeoramiento de la función de tejido, particularmente prominentes en individuos muy viejos (geriátricos) que padecen sarcopenia. La pérdida muscular asociado a la edad, se acompaña de una reducción en la capacidad de regeneración del músculo y en una reducción del número y la función de las células madre residentes en el músculo (células satélite). Aunque la sarcopenia sea una de las causas principales de la pérdida general de función fisiológica del músculo, los mecanismos implicados en la reducción de la homeostasis muscular y de actividad de las células satélite no han sido completamente caracterizados. Mediante el análisis comparativo del transcriptoma de células madre musculares aisladas de ratones jóvenes y de ratones viejos (geriátricos), hemos encontrado cambios específicos en su perfil de expresión génica que apuntan a los procesos biológicos dominantes y a los marcadores moleculares potencialmente asociados con el envejecimiento de las células satélite, entre los que destaca p16INK4a. Por ello, hemos utilizado ratones deficientes en Bmi1 para explorar más profundamente las implicaciones de la sobreexpresión de p16INK4a en la función de las células satélite. Hemos encontrado que células satélite jóvenes del ratón Bmi1-/- presentan sobrexpresión de p16INK4a, que correlacionan con una reducción en el número de la células, y en su capacidad de proliferación y autorenovación. Además hemos identificado un grupo de procesos biológicos comunes entre las células satélite viejas y las deficientes en Bmi1, sugiriendo que la regulación epigenética mediada por Bmi1 puede ser la base de muchos de los cambios intrínsecos que ocurren en células envejecidas fisiológicamente. Además, demostramos que la pérdida Bmi1 causa defectos en el crecimiento postnatal/adulto del músculo, caracterizado por pérdida de masa muscular con fibras más pequeñas, típico del músculo atrofiado senescente o sarcopénico. Puesto que la expresión de p16 está aumentada específicamente en el músculo de ratones viejos, sarcopénicos y en un modelo del ratón con envejecimiento (senescencia) acelerado (SAMP8), proponemos que el eje Bmi1/p16 puede actuar particularmente en las células madre musculares de los ancianos. La pérdida de masa muscular es una de las consecuencias fisiológicas de la sarcopenia y la identificación de nuevos factores que regulen el crecimiento y atrofia del músculo es de gran importancia para aplicaciones terapéuticas. Hemos descubierto un nuevo papel de las Sestrinas como factores promotores del crecimiento del músculo esquelético en el adulto. Hemos encontrado que la expresión de las Sestrinas se regula en modelos del ratón de atrofia y de hipertrofia muscular y en miopatías humanas. Mediante experimentos de ganacia de función hemos demostrado que las Sestrinas inducen el crecimiento del músculo esquelético, activando el ruta de señalización de IGF1/PI3K/AKT
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Kim, Hee-Jung. "I. studies of AD5 E3-14.7K, an Adenoviral Inhibitor of TNF receptor- and FAS-mediated Apoptosis ; II. investigation of interactions between Cyclin-dependent Kinase 4 and tumor suppressor p16(INK4A) /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488203552778889.
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Souza, Felipe da Costa. "Geração e caracterização de linhagens isogênicas portadoras de mutantes de p53: modelo para avaliar a estratégia de reparação dos genes p53 e p16 INK4A na presença dos mutantes p53R175H e p53R248Q." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/42/42134/tde-26072012-102241/.
Full textAbstract:
A destruição funcional das vias de controle do ciclo celular constituem um evento comuns em todos os tumores humanos. Muitos estudos associam mutações em p53 com mau prognostico no tratamento do câncer. Nesse trabalho, visamos a geração e caracterização de linhagens isogênicas portando diferentes mutantes de p53 como modelo de estudo para remediação simultânea de p53 e p16 na presença de mutantes hotspots específicos. Os mutantes R175H e R248Q não geraram alterações na cinética de proliferação da linhagem H358, mas levaram a um aumento de 27,5% na eficiência de plaqueamento e, no caso de R248Q, ao dobro de eficiência na formação de colônias em suspensão. Os resultados do tratamento das linhagens isogênicas com adenovírus Adp16 e Adp53 mostraram que os mutantes não interferiram no parada do ciclo celular em G1 induzida por p16.Alterations of the cell cycle pathway are a common event in all human tumors. Several studies have shown a correlation between hotspot mutations and an unfavorable profile for cancer therapies. Hence, this study aims the generation and characterization of isogenic cell lines, harboring p53 mutants, as model to investigate the replacement of p53 and p16 genes on these mutant H358 cell lines. Our data identified that neither p53R175H nor p53R248Q mutants accelerated cell cycle progression. However, both leads to a 27,5% increased plate efficiency while R248Q leads to a two-fold increases in the number of colonies formed in soft agar. Our data also showed that the mutants did not affect the efficiency of p16 replacement.
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Portari, Elyzabeth Avvad. "Estudo de polimorfismos nos genes TP53 e p21(WAF1) e do perfil imunohistoquímico das proteínas p53, p21(WAF1), p16(INK4a) e ciclina D1 pela técnica de Tissue Microarray (TMA) e sua importância para o desenvolvimento e/ou severidade das neoplasias cervicais." Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9228.
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O câncer de colo do útero é o terceiro tipo de câncer mais frequente em mulheres no mundo, e a infecção persistente pelo papilomavirus humano (HPV) oncogênico é condição necessária, mas não suficiente para seu desenvolvimento. As oncoproteínas virais E6 e E7 interferem direta ou indiretamente na ação de várias proteínas celulares. Entretanto, as variantes proteicas, resultantes de polimorfismos genéticos, podem apresentar comportamento distinto mediante a infecção pelo HPV. O objetivo deste estudo foi avaliar possíveis associações entre polimorfismos nos genes TP53 (p53 PIN3, p53 72C>G) e p21 (p21 31C>A) e o desenvolvimento de neoplasias cervicais, considerando os níveis de expressão das proteínas p53, p21, p16 e ciclina D1, e fatores de risco clássicos para o câncer cervical. Foram selecionadas 466 mulheres residentes no Rio de Janeiro, 281 com diagnóstico histopatológico de neoplasia cervical de baixo (LSIL) e alto grau (HSIL) e câncer (grupo de casos) e 185 sem história atual ou pregressa de alteração citológica do colo uterino (grupo controle). A técnica de PCR-RFLP (reação em cadeia da polimerase - polimorfismo de comprimento de fragmento de restrição), foi empregada na análise dos polimorfismos p53 72C>G e p21 31C>A, usando as enzimas de restrição BstUI e BsmaI, respectivamente. A avaliação do polimorfismo p53 PIN3 (duplicação de 16 pb) foi feita por meio da análise eletroforética direta dos produtos de PCR. A expressão das proteínas p53, p21, p16, ciclina D1 e Ki-67 e a pesquisa de anticorpos anti-HPV 16 e HPV pool foram avaliadas por imunohistoquímica (Tissue Microarray - TMA) em 196 biópsias do grupo de casos. O grupo controle se mostrou em equilíbrio de Hardy-Weinberg em relação aos três polimorfismos avaliados. As distribuições genotípicas e alélicas relativas a p53 PIN3 e p53 72C>G nos grupos controles e de casos não apresentaram diferenças significativas, embora o genótipo p53 72CC tenha aumentado o risco atribuído ao uso de contraceptivos das pacientes apresentarem lesões mais severas (OR=4,33; IC 95%=1,19-15,83). O genótipo p21 31CA(Ser/Arg) conferiu proteção ao desenvolvimento de HSIL ou câncer (OR=0,61, IC 95%=0,39-0,97), e modificou o efeito de fatores de risco associados à severidade das lesões. A interação multiplicativa de alelos mostrou que a combinação p53 PIN3A1, p53 72C(Pro) e p21 31C(Ser), representou risco (OR=1,67, IC95%=1,03-2,72) e a combinação p53 PIN3A1, p53 72C(Pro) e p21 31A(Arg) conferiu efeito protetor (OR=0,26, IC95%=0,08-0,78) para o desenvolvimento de HSIL e câncer cervical. Observou-se correlação positiva da expressão de p16 e p21 e negativa da ciclina D1 com o grau da lesão. A distribuição epitelial de p16, Ki-67, p21 e p53 se mostrou associada à severidade da lesão. Os polimorfismos analisados não apresentaram associação com a expressão dos biomarcadores ou positividade para HPV. Nossos resultados sugerem a importância do polimorfismo p21 31C>A para o desenvolvimento das neoplasias cervicais e ausência de correlação dos polimorfismos p53 PIN3 e p53 72C>G com a carcinogênese cervical, embora alguns genótipos tenham se comportado como modificadores de risco. Nossos resultados de TMA corroboram o potencial de uso de biomarcadores do ciclo celular para diferenciar as lesões precursoras do câncer cervical.Cervical cancer is the third most common female cancer worldwide, and persistent infection by the Human Papillomavirus (HPV) is a necessary but not sufficient condition to cause it. The viral oncoproteins E6 and E7 interfere directly or indirectly with the action of various cellular proteins. However, the protein variants, resulting from genetic polymorphisms, may act differently when encountering HPV infection. The aim of this study was to evaluate possible associations between polymorphisms in the TP53 (p53 PIN3, p53 72C>G) and p21 (p21 31C>A) genes, and the development of cervical neoplasia, considering the expression levels of p53, p21, p16 and cyclin D1 proteins, together with classic risk factors for cervical cancer. A total of 466 women resident in Rio de Janeiro were selected, being 281 with histopathological diagnosis of low (LSIL) or high grade (HSIL) cervical neoplasia or cancer (test group), and 185 with no current or previous history of alteration of cervical cytology (control group). The PCR-RFLP technique (polymerase chain reaction restriction fragment length polymorphism) was used to analyze the p53 72C>G and p21 31C>A polymorphisms, using BstUI and BsmaI restriction enzymes, respectively. Genotyping of the p53 PIN3 (duplication of 16 pb) polymorphism was performed by direct electrophoretic analysis of the PCR products. The expression of p53, p21, p16, cyclin D1 and Ki-67 proteins and the study of anti-HPV 16 and anti-HPV pool positivities were evaluated by immunohistochemisty (Tissue Microarray - TMA) in 196 biopsies of cases. The control group obeyed the Hardy-Weinberg principle in relation to the three polymorphisms analysed. The genotypic and allelic frequencies regarding p53 PIN3 and p53 72C>G in the control and test groups were not significantly different, although the p53 72CC genotype has increased the risk of more severe lesions attributed to the use of contraceptives (OR=4.33; IC 95%=1.19-15.83). The p21 31CA(Ser/Arg) genotype showed to protect against the development of HSIL or cancer (OR=0,61, IC 95%=0,39-0,97), and modified the effect of risk factors associated to the lesion severity. The multiplicative interaction of alleles showed that the combination p53 PIN3A1, p53 72C(Pro) and p21 31C(Ser) represented risk (OR=1,67, IC95%=1,03-2,72) and the combination p53 PIN3A1, p53 72C(Pro) and p21 31A(Arg) conferred protection (OR=0,26, IC95%=0,08-0,78) against the development of HSIL and cervical cancer. It was observed positive and negative correlations of, respectively, p16 and p21, and cyclin D1 expression with the cervical lesion grade. The epithelial distribution of p16, Ki-67, p21 and p53 was associated with the lesion severity. The polymorphisms analyzed showed neither association with the expression of the biomarkers nor positivity for HPV. Our results suggest the importance of polymorphism p21 31C>A in the development of cervical neoplasia and the lack of correlation between the polymorphisms p53 PIN3 and p53 72C>G with cervical carcinogenesis, although some genotypes acted as risk modifiers. Our TMA results corroborated the potential use of cell cycle biomarkers as an adjunctive tool to differentiate cervical precursor lesions.
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Lokody, Isabel Beatrice. "The role of p16(INK4A) in SMAD signalling." 2007. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=789029&T=F.
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Agatep, Ronald. "Germline CDKN2A mutations and the p16(INK4A) interaction network." 2007. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=478912&T=F.
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Blazar, Ilyse Natasha. "Differential effects of epidermal growth factor receptor inhibitors on glioblastoma multiforme." Thesis, 2015. https://hdl.handle.net/2144/16128.
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OBJECTIVE: Glioblastoma Multiforme (GBM), one of the most malignant forms of primary brain tumors, is characterized by its highly heterogenous genetic composition, aggressive infiltration of surrounding tissue, and resistance to current treatments. Gene expression analysis has characterized GBM into four main types, with a significant portion belonging to the Classical subtype, typified by overexpression and/or mutation of the epidermal growth factor receptor (EGFR). Also common to this subtype of GBM is the loss of crucial tumor suppressor genes Ink4A/ARF and PTEN, which contribute to the invasive nature and unregulated proliferation that underlie the GBM pathology. The high rate of tumor recurrence post treatment with surgical resection, chemotherapy, and radiation has driven the pursuit of more effective molecularly targeted therapies. This study was undertaken to determine the effects of two types of small molecule tyrosine kinase inhibitors on cells overexpressing wild-type EGFR in the context of their respective complements of tumor suppressor genes.
METHODS: Several cell lines were established from mouse models of EGFR wild-type (EGFRWT) driven gliomagenesis and treated with 10 μM of type I tyrosine kinase inhibitors Gefitinib (Iressa®, Astra Zeneca), CI-1033 (Canertinib, Pfizer), or Dimethyl Sulfoxide vehicle. Cells were exposed to each drug treatment as part of a time course ranging from 0 to 24 hours and then evaluated by trypan blue exclusion and Western blot analysis for cell viability and molecular and biochemical effects respectively.
RESULTS: Evaluation of cell viability indicated that CI-1033 caused a greater increase in cell death than gefitinib when compared to control treated cells regardless of the tumor suppressors lost. Gefitinib was found to cause cell death only in cells expressing the PTEN tumor suppressor whereas CI-1033 showed similar levels of cell death for cells deficient in Ink4A/ARF or both Ink4A/ARF and PTEN tumor suppressors. Western blot analysis revealed that CI-1033 more effectively inhibited EGFR compared to gefitinib. Treatment with both gefitinib and CI-1033 effectively blocked phosphorylation of EGFR, but this effect was less pronounced with gefitinib treatment. Further analysis of downstream signaling molecules showed a greater presence of cleaved caspase 3, a hallmark of apoptosis, in gefitinib treated cells expressing PTEN than in those cells treated with CI-1033. Cells deficient in both Ink4A/ARF and PTEN did not demonstrate any induction of cleaved caspase 3 following either treatment.
CONCLUSIONS: Based on the significant differences in cell viability between treatments, CI-1033 is an overall more effective inhibitor of EGFRWT expressing cells lacking PTEN, while gefitinib and CI-1033 were found to be similarly effective in cells expressing PTEN. The results of western blot analysis indicate that total and irreversible EGFR inhibition may be necessary to induce cell death in a manner that effectively terminates downstream cell signaling. It is likely that CI-1033, unlike gefitinib, induces apoptosis in a caspase-independent manner, which may be one of the many differences in downstream effects produced by these two drugs. Further research is necessary to determine the extent to which each inhibitor shuts down proliferative cell signaling pathways such as PI3K-AKT and MEK-ERK signaling pathways downstream of EGFR. Overall, these data indicate that genotype plays an important role in the determination of therapeutic response and may aid in the evaluation of clinical prognoses.
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Voß, Martin Henner [Verfasser]. "p16-INK4a controls the morphology program associated with cellular senescence / vorgelegt von Martin Henner Voß." 2005. http://d-nb.info/976851105/34.
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Émond, Pierre-Olivier. "Les cibles transcriptionnelles du polycomb Rae28 lors du développement de l'oeil : l'hypothèse du locus Ink4a/Arf." Thèse, 2008. http://hdl.handle.net/1866/7631.
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Franke, Dirk. "Quantitative Expressionsanalyse der beiden p16-Transkripte p16 INK4a und p19 ARF in Lymphozyten von CML-Patienten /." 2004. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=013133390&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Ocon, Erika [Verfasser]. "Das Tumorsuppressorgen p16/INK4a in epithelialen Ovarialkarzinomen : eine Mutations-, Expressions- und Methylierungsanalyse / vorgelegt von Erika Ocon." 2004. http://d-nb.info/972278826/34.
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To, Kwong Him. "Role of the Tumor Suppressor ARF and the p53-pathway in Retinoblastoma Development." Thesis, 2009. http://hdl.handle.net/1807/18965.
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Retinoblastoma development is a multistep process, and inactivation of the RB1 gene is not sufficient for tumorigenesis. Previous studies suggest that the p53-tumor suppressor is inactivated due to overexpression of p53-antagonists MDM4 and MDM2. This thesis evaluates the importance of ARF, a p53-activator that inhibits MDM2. In retinoblastomas, ARF protein is nearly undetectable despite robust mRNA expression. Chemical inhibition of the proteasome, which regulates ARF protein-turnover, did not result in ARF accumulation in retinoblastoma cells, indicating that ARF protein was not aberrantly degraded by the proteasome. During mouse retinoblastoma development, Arf protein was expressed at low level, and p53-target genes involved in cell cycle arrest and autoregulation were not activated. Overexpression of ARF in retinoblastoma cells led to growth inhibition, accompanied by increased expression of p53 and p53-transcriptional targets. Taken together, our data suggests that low ARF protein is an important factor in silencing of the p53-pathway during retinoblastoma development.
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Helmrich, Anne [Verfasser]. "Genomweite molekular-zytogenetische Charakterisierung INK4A/ARF-defizienter Mauslymphome und Untersuchungen zur evolutionären Konservierung von Common fragile sites / von Anne Helmrich." 2005. http://d-nb.info/97675679X/34.
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Carbonneau, Cynthia. "Étude des effets du phénotype de sénescence des cellules stromales de la moelle osseuse sur les fonctions hématopoïétiques." Thèse, 2012. http://hdl.handle.net/1866/9074.
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L’irradiation (IR) est utilisée dans le traitement de plusieurs cancers et désordres
hématologiques, en particulier dans les protocoles de conditionnement précédents les
transplantations de moelle osseuse. L’emploi de doses réduites d’IR semble favoriser le
succès de la prise de greffe. Cette observation soulève un point de plus en plus discuté dans la littérature, soit l’importance de l’intégrité du microenvironnement pour la
transplantation et le bon fonctionnement de l’hématopoïèse. L’IR induit la sénescence des
cellules stromales de la moelle osseuse in vitro. Ce mécanisme de défense cellulaire
entraînant un arrêt de prolifération permanent est également observé in vivo dans
différents systèmes, mais n’a pas encore été étudié dans le contexte de la niche
hématopoïétique. Les travaux présentés dans cette thèse ont pour objectif de déterminer si l’IR induit la sénescence des cellules stromales de la moelle osseuse et si une telle induction altère les fonctions hématopoïétiques. Nos résultats ont permis de démontrer pour la première fois qu’une IR corporelle totale induit effectivement la sénescence des cellules stromales de la moelle osseuse. En outre, cette altération du microenvironnement affecte la lymphopoïèse B de façon Ink4a/Arf-dépendante (1er article). De plus, les modifications systémiques qui résultent de l’IR compromettent l’homéostasie osseuse en
augmentant la résorption de l’os, sans toutefois diminuer la formation de celui-ci (2e article). Ces données nous permettent de mieux comprendre les effets de la sénescence
des cellules stromales de la moelle osseuse sur les fonctions hématopoïétiques. Par
ailleurs, elles suggèrent que l’emploi de drogues et/ou de procédés n’induisant pas la
sénescence des cellules stromales de l’os offrirait un meilleur pronostic à long terme pour les patients.Ionizing radiation (IR) is used in the treatment of several cancers and hematological disorders, especially in conditioning regimens for bone marrow transplantation. Reduced doses of IR seem to favor the success of engraftment. This observation supports the growing evidences suggesting the importance of the microenvironment integrity for the success of bone marrow transplantation and hematopoiesis maintenance. IR induces senescence of bone marrow stromal cells in vitro. This defense mechanism which leads to a permanent cell growth arrest is also observed in different organs in vivo but has not yet been studied in the hematopoietic niche. The objectives of this doctoral thesis are to determine whether IR induces senescence of bone marrow stromal cells and whether such induction alters hematopoietic functions. Our results have demonstrated for the first time that total body IR actually induces the senescence of bone marrow stromal cells. Furthermore, this alteration of the microenvironment affects B lymphopoiesis in an Ink4a/Arf-dependent manner (paper #1). In addition, the systemic changes associated with IR compromise bone homeostasis by increasing bone resorption without reducing bone formation (paper #2). All together, these data enhance our knowledge related to the effects of IR-induced senescent bone marrow stromal cells on hematopoietic function. Moreover, our results suggest that using drugs and/or procedures inducing no senescent bone marrow stromal cells would provide a better long-term prognosis for patients.
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Palacio, Lina. "Study of the role of the p16INK4a gene in tumor progression and tissue regeneration/function following exposure to ionizing radiation." Thesis, 2017. http://hdl.handle.net/1866/24855.
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La sénescence est un important mécanisme cellulaire qui prévient la tumorigenèse et se caractérise par un arrêt permanent du cycle cellulaire orchestré principalement par les inhibiteurs des cycline-kinases dépendantes (i.e p16INK4a). La sénescence est une caractéristique importante du vieillissement, mais un déséquilibre dans son induction peut être délétère pour la régénération tissulaire et paradoxalement pour la progression tumorale. L'irradiation (IR) est couramment utilisée comme approche thérapeutique dans le cancer. Chez les enfants survivants du cancer, l’exposition à l’irradiation et à la chimiothérapie entrainent le développement d’importants effets secondaires, lesquels sont associés à une forme de vieillissement prématuré. La formation de cellules sénescentes, en inhibant la prolifération tissulaire et en sécrétant des cytokines proinflammatoires, pourrait être en être responsable. Notre groupe a précédemment démontré que le gène p16INK4a est augmenté de manière tardive (environ 8 semaines) suite à une exposition à l’irradiation. Il n'a pas encore été étudié si cette expression retardée survient en réponse aux dommages causés par l'irradiation sur l’homéostasie tissulaire ou à titre de mécanismes de suppression tumorale. Un objectif de cette thèse visait donc à déterminer s’il était possible de moduler/inhiber l’expression de p16INK4a dans le but d’accroitre la régénération tissulaire sans nécessairement accroitre les risques d’incidence du cancer. En effet, ceci pourrait être possible dans la mesure ou la sénescence induite par p16INK4a est également irréversible in vivo. Nos résultats ont démontré que l’inhibition de l’expression de p16INKa (suite à l’administration de tamoxifen chez les souris p16L/LCre), induit à la fois une augmentation de la régénération tissulaire mais malheureusement également une augmentation de l’incidence du cancer. Nous
voulions également connaitre l’impact de l’accumulation de ces cellules sénescentes sur les tissus, plus spécifiquement sur la fonction des cellules immunitaires de la rate. Nous avons démontré que des altérations (dépendantes de p16INK4a) au sein du microenvironnement splénique pouvaient altérer les fonctions intrinsèques des macrophages, des cellules dendritiques et des lymphocytes T. En outre, l'élimination systémique des cellules p16INK4a positives (modèle de sourie p16-3MR) a conduit à une restauration partielle de la fonction de ces cellules immunitaires. La combinaison de ces données nous permet de mieux comprendre le rôle et la fonction du gène p16INK4a dans le processus de sénescence induite par l’irradiation. Nos résultats suggèrent qu’il est envisageable d’utiliser des agents pharmacologiques tels que des composés sénolytiques, capables d’induire l’apoptose chez les cellules sénescentes spécifiquement, afin de potentiellement diminuer les effets du vieillissement prématuré induit par la sénescence cellulaire chez les survivants du cancer.Senescence is an important cellular mechanism that prevents tumorigenesis and is characterized by a permanent cell cycle arrest orchestrated by cyclin-dependent kinases inhibitors (i.e p16INK4a). Senescence is an important hallmark of aging and unbalanced levels of senescence is considered deleterious for tissue regeneration, and paradoxically for tumor progression. Irradiation (IR) is commonly used therapeutic approach in cancer treatment. Together with surgery and chemotherapy, it has helped to increase the life expectancy of patients and, in some cases, leads to complete remission. However, long-after therapy, children who survive cancer encounter alterations in the integrity of tissues/organs associated with premature aging. The accumulation of senescent cells may be responsible for this accelerated aging by limiting tissue proliferation and secreting pro-inflammatory cytokines. Our group has previously demonstrated that the p16INK4a gene is increased in a delayed manner (approximately 8 weeks) following exposure to IR. It has not yet been investigated whether this delayed expression occurs in response to IR-induce damage of tissue homeostasis or as tumor suppression mechanisms. One objective of this thesis was to determine whether it was possible to modulate / inhibit the expression of p16INK4a in order to increase tissue regeneration without necessarily increasing the risk of cancer incidence. Indeed, this may be possible since p16INK4a-induced senescence is also irreversible in vivo. Our results demonstrated that the inhibition of p16INK4a expression in conditional-p16INK4a null mice , induces both an increase in tissue regeneration but unfortunately also an increase in the incidence of cancer. We also wanted to know the impact of the accumulation of these senescent cells on the tissues, more specifically on the function of the immune cells in the spleen. We have demonstrated that alterations (p16INK4a-dependent) within the splenic microenvironment can alter the intrinsic functions of macrophages, dendritic cells and T cells. In addition, the systemic elimination of p16INK4a positive cells (mouse model p16-3MR) has led to a partial restoration of the function of these immune cells. The combination of these data allows us to better understand the role and function of the p16INK4a gene in the irradiation-induced senescence process. Our results suggest that it is conceivable to use pharmacological agents such as senolytic compounds, capable of inducing apoptosis in senescent cells specifically, in order to potentially reduce the effects of premature aging induced by cellular senescence in cancer survivors.
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Nováková, Gita. "Charakterizace vlivu senescence na indukci a regulaci smrti nádorových buněk." Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-332198.
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4 Abstract Senescence is a specific cell state distinquished by cessation of cell division and proliferation and changes in gene expression. Normal cells enter senescence after distinct number of cell divisions or in case of an unrepairable damage. Senescence in cancer cells can be induced by subliminal stress as sublethal treatment with certain drugs. Senescent cancer cells persist in the tissue and may secrete a number of factors and nutrients affecting surrounding cells. Senescence can thus change the response of cancer cells to various apoptogens during cancer therapy. In this study, we focused on the elucidation of presumed differences between normal proliferating and senescent cancer cells in their response to selected apoptogens. Implementing bromodeoxyuridine (BrdU)-mediated replication stress in cancer cells derived from pancreatic (PANC-1) or mesothelioma (H28) tumors, we efficiently forced these cells to acquire senescent phenotype. We document that these senescent cells gain higher resistance to combined TRAIL and homoharringtonine (HHT) treatment and enhance sensitivity to other apoptogens such as FasL, camptothecin and mVES. These cells also showed increased expression of anti-apoptotic protein c-FLIP in senescent cells and changes in the expression of some Bcl-2 family proteins....