Q77898702
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Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
Nestr.
Vysokokapacitní cílené sekvenování nové generace (NGS) umožňuje paralelní vyšetření mnoha nádorových predispozičních genů (panelů) u onkologicky nemocných s podezřením na výskyt dědičného nádorového syndromu. Identifikace nosičů patogenních mutací u pacientů a jejich příbuzných má zásadní prognostický ale i prediktivní význam. Plnou implementaci výsledků NGS do klinické péče o tyto vysoce rizikové osoby omezuje interpretace nacházených variant s nejasným klinickým významem (VUS). Pro zlepšení diagnostického přínosu NGS u nádorových syndromů provedeme komplexní bioinformatickou reanalýzu dat z nádorových NGS panelů (získaných při rutinních vyšetřeních indikovaných nemocných ve 4 centrech v ČR) a asociaci nalezených variant s klinickými a histopatologickými údaji pacientů. Analýza nádorového NGS panelu u 1000 nenádorových kontrol umožní identifikaci populačně specifického genetického pozadí. Vybrané VUS se zjištěným rekurentním výskytem budou charakterizovány pomocí in silico přístupů a funkčních in vitro testů identifikujících patogenetické mechanismy jejich působení.; High-throughput targeted next-gen sequencing (NGS) enable simultaneous analysis of many cancer-susceptibility genes (panels) in oncological patients with suspected hereditary cancer syndrome. Identification of pathogenic mutations in high-risk patients and their relatives has high prognostic and predictive importance. The utility of NGS data for clinical management of high-risk patients is hampered by complicated interpretation of variants of uncertain significance (VUS). In order to improve the diagnostic power of NGS, we will perform comprehensive reanalysis of NGS cancer panel data (obtained from analyses of high-risk individuals at 4 large Czech centers) and correlation of these data with patients’ clinical and histopathological characteristics. To uncover population specific genetic background, we will perform cancer panel NGS analysis of 1000 non-cancer controls. The VUS in cancer-susceptibility genes will be analyzed by in silico approaches. To describe mechanisms of their pathogenicity, selected recurrent variants will be enrolled into the in vitro functional analysis.
- MeSH
- dědičné nádorové syndromy diagnóza genetika MeSH
- genetické asociační studie MeSH
- lidé MeSH
- mutace genetika MeSH
- prognóza MeSH
- výpočetní biologie metody MeSH
- vysoce účinné nukleotidové sekvenování metody MeSH
- Check Tag
- lidé MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- onkologie
- genetika, lékařská genetika
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
Nestr.
Maligní melanom (MM) představuje nejagresivnější typ kožních nádorů s vysokým metastatickým potenciálem a nepříznivou prognózou. Rozvoj poznatků týkajících se molekulárních mechanismů podmiňujících rozvoj MM a nalezení nových biomarkerů je potřebné pro přesnou diagnostiku a volbu léčebných postupů. V předkládaném projektu plánujeme provést komplexní studii založenou na sekvenování nové generace, in situ hybridizaci a imunohistochemické analýze se zaměřením na defekty v onkogenech a tumor supresorových genech zapojených do rozvoje MM, expresi proteinů a charakteristiku stromálního mikroprostředí. Funkční význam vybraných mutací bude dále testován na kulturách melanocytů, především se zaměřením na jejich roli v odpovědi na poškození DNA a regulaci buněčného cyklu. Nalezené změny na genetické úrovni budou korelovány s histopatologickým obrazem, imunohistochemickým profilem a s klinickými daty. Očekáváme prohloubení znalostí o známých a identifikaci nových biomarkerů umožňujících lepší predikci, diagnostiku a léčbu MM.; Malignant melanoma represents the most aggressive type of skin cancer with high metastatic potential and poor prognosis. Better understanding of molecular mechanisms involved in pathogenesis of melanoma and identification of novel biomarkers is needed for precise diagnostic classification and prediction of therapeutical outcomes. Here we aim to perform a comprehensive study employing next-generation sequencing, in situ hybridisation and immunohistochemical analysis to identify new defects in oncogenes and tumour suppressor genes involved in melanoma, protein expression and characterization of stromal microenvironment. Selected mutations will be functionally tested in culture of melanocytes, focusing mainly on their role in DNA damage response and cell cycle checkpoints. Identified genetic changes will be correlated with histopathological findings, immunohistochemical profile and clinical data. We expect deepening of known and identification of new markers allowing better prediction, diagnosis and treatment of melanoma.
- MeSH
- geny p53 genetika MeSH
- hybridizace in situ MeSH
- imunohistochemie metody MeSH
- lidé MeSH
- melanom genetika mikrobiologie MeSH
- mutace MeSH
- nádorové biomarkery MeSH
- onkogeny genetika MeSH
- vysoce účinné nukleotidové sekvenování metody MeSH
- Check Tag
- lidé MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- genetika, lékařská genetika
- onkologie
- mikrobiologie, lékařská mikrobiologie
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
BACKGROUND: Monoallelic germline pathogenic variants (GPVs) in five Fanconi anemia (FA) genes (BRCA1/FANCS, BRCA2/FANCD1, PALB2/FANCN, BRIP1/FANCJ, and RAD51C/FANCO) confer an increased risk of breast (BC) and/or ovarian (OC) cancer, but the role of GPVs in 17 other FA genes remains unclear. METHODS: Here, we investigated the association of germline variants in FANCG/XRCC9 with BC and OC risk. RESULTS: The frequency of truncating GPVs in FANCG did not differ between BC (20/10,204; 0.20%) and OC (8/2966; 0.27%) patients compared to controls (6/3250; 0.18%). In addition, only one out of five tumor samples showed loss-of-heterozygosity of the wild-type FANCG allele. Finally, none of the nine functionally tested rare recurrent missense FANCG variants impaired DNA repair activities (FANCD2 monoubiquitination and FANCD2 foci formation) upon DNA damage, in contrast to all tested FANCG truncations. CONCLUSION: Our study suggests that heterozygous germline FANCG variants are unlikely to contribute to the development of BC or OC.
- MeSH
- dospělí MeSH
- genetická predispozice k nemoci * MeSH
- lidé středního věku MeSH
- lidé MeSH
- nádory prsu * genetika MeSH
- nádory vaječníků * genetika MeSH
- oprava DNA genetika MeSH
- protein FANCG * genetika MeSH
- senioři MeSH
- studie případů a kontrol MeSH
- zárodečné mutace * MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Oncogene-induced replication stress has been recognized as a major cause of genome instability in cancer cells. Increased expression of cyclin E1 caused by amplification of the CCNE1 gene is a common cause of replication stress in various cancers. Protein phosphatase magnesium-dependent 1 delta (PPM1D) is a negative regulator of p53 and has been implicated in termination of the cell cycle checkpoint. Amplification of the PPM1D gene or frameshift mutations in its final exon promote tumorigenesis. Here, we show that PPM1D activity further increases the replication stress caused by overexpression of cyclin E1. In particular, we demonstrate that cells expressing a truncated mutant of PPM1D progress faster from G1 to S phase and fail to complete licensing of the replication origins. In addition, we show that transcription-replication collisions and replication fork slowing caused by CCNE1 overexpression are exaggerated in cells expressing the truncated PPM1D. Finally, replication speed and accumulation of focal DNA copy number alterations caused by induction of CCNE1 expression was rescued by pharmacological inhibition of PPM1D. We propose that increased activity of PPM1D suppresses the checkpoint function of p53 and thus promotes genome instability in cells expressing the CCNE1 oncogene.
Cell cycle checkpoints, oncogene-induced senescence and programmed cell death represent intrinsic barriers to tumorigenesis. Protein phosphatase magnesium-dependent 1 (PPM1D) is a negative regulator of the tumour suppressor p53 and has been implicated in termination of the DNA damage response. Here, we addressed the consequences of increased PPM1D activity resulting from the gain-of-function truncating mutations in exon 6 of the PPM1D. We show that while control cells permanently exit the cell cycle and reside in senescence in the presence of DNA damage caused by ionising radiation or replication stress induced by the active RAS oncogene, RPE1-hTERT and BJ-hTERT cells carrying the truncated PPM1D continue proliferation in the presence of DNA damage, form micronuclei and accumulate genomic rearrangements revealed by karyotyping. Further, we show that increased PPM1D activity promotes cell growth in the soft agar and formation of tumours in xenograft models. Finally, expression profiling of the transformed clones revealed dysregulation of several oncogenic and tumour suppressor pathways. Our data support the oncogenic potential of PPM1D in the context of exposure to ionising radiation and oncogene-induced replication stress.
- MeSH
- buněčná smrt genetika MeSH
- lidé MeSH
- myši MeSH
- nádorová transformace buněk * genetika MeSH
- nádorový supresorový protein p53 genetika metabolismus MeSH
- poškození DNA * genetika MeSH
- proliferace buněk genetika MeSH
- proteinfosfatasa 2C * genetika metabolismus MeSH
- proteinfosfatasy genetika metabolismus MeSH
- stárnutí buněk * genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
RAD18 is an E3 ubiquitin ligase that prevents replication fork collapse by promoting DNA translesion synthesis and template switching. Besides this classical role, RAD18 has been implicated in homologous recombination; however, this function is incompletely understood. Here, we show that RAD18 is recruited to DNA lesions by monoubiquitination of histone H2A at K15 and counteracts accumulation of 53BP1. Super-resolution microscopy revealed that RAD18 localizes to the proximity of DNA double strand breaks and limits the distribution of 53BP1 to the peripheral chromatin nanodomains. Whereas auto-ubiquitination of RAD18 mediated by RAD6 inhibits its recruitment to DNA breaks, interaction with SLF1 promotes RAD18 accumulation at DNA breaks in the post-replicative chromatin by recognition of histone H4K20me0. Surprisingly, suppression of 53BP1 function by RAD18 is not involved in homologous recombination and rather leads to reduction of non-homologous end joining. Instead, we provide evidence that RAD18 promotes HR repair by recruiting the SMC5/6 complex to DNA breaks. Finally, we identified several new loss-of-function mutations in RAD18 in cancer patients suggesting that RAD18 could be involved in cancer development.
- MeSH
- 53BP1 * metabolismus genetika MeSH
- chromatin * metabolismus genetika MeSH
- DNA vazebné proteiny * metabolismus genetika MeSH
- dvouřetězcové zlomy DNA * MeSH
- histony * metabolismus MeSH
- homologní rekombinace genetika MeSH
- lidé MeSH
- oprava DNA spojením konců MeSH
- oprava DNA MeSH
- proteiny buněčného cyklu metabolismus genetika MeSH
- rekombinační oprava DNA MeSH
- replikace DNA MeSH
- ubikvitinace * MeSH
- ubikvitinligasy * metabolismus genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE: Germline pathogenic variants in CHEK2 confer moderately elevated breast cancer risk (odds ratio, OR ∼ 2.5), qualifying carriers for enhanced breast cancer screening. Besides pathogenic variants, dozens of missense CHEK2 variants of uncertain significance (VUS) have been identified, hampering the clinical utility of germline genetic testing (GGT). EXPERIMENTAL DESIGN: We collected 460 CHEK2 missense VUS identified by the ENIGMA consortium in 15 countries. Their functional characterization was performed using CHEK2-complementation assays quantifying KAP1 phosphorylation and CHK2 autophosphorylation in human RPE1-CHEK2-knockout cells. Concordant results in both functional assays were used to categorize CHEK2 VUS from 12 ENIGMA case-control datasets, including 73,048 female patients with breast cancer and 88,658 ethnicity-matched controls. RESULTS: A total of 430/460 VUS were successfully analyzed, of which 340 (79.1%) were concordant in both functional assays and categorized as functionally impaired (N = 102), functionally intermediate (N = 12), or functionally wild-type (WT)-like (N = 226). We then examined their association with breast cancer risk in the case-control analysis. The OR and 95% CI (confidence intervals) for carriers of functionally impaired, intermediate, and WT-like variants were 2.83 (95% CI, 2.35-3.41), 1.57 (95% CI, 1.41-1.75), and 1.19 (95% CI, 1.08-1.31), respectively. The meta-analysis of population-specific datasets showed similar results. CONCLUSIONS: We determined the functional consequences for the majority of CHEK2 missense VUS found in patients with breast cancer (3,660/4,436; 82.5%). Carriers of functionally impaired missense variants accounted for 0.5% of patients with breast cancer and were associated with a moderate risk similar to that of truncating CHEK2 variants. In contrast, 2.2% of all patients with breast cancer carried functionally wild-type/intermediate missense variants with no clinically relevant breast cancer risk in heterozygous carriers.
- MeSH
- checkpoint kinasa 2 genetika MeSH
- genetická predispozice k nemoci MeSH
- lidé MeSH
- missense mutace MeSH
- nádory prsu * epidemiologie genetika MeSH
- zárodečné buňky MeSH
- zárodečné mutace MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Hematopoietic stem cells (HSCs) ensure blood cell production during the life-time of an organism, and to do so they need to balance self-renewal, proliferation, differentiation, and migration in a steady state as well as in response to stress or injury. Importantly, aberrant proliferation of HSCs leads to hematological malignancies, and thus, tight regulation by various tumor suppressor pathways, including p53, is essential. Protein phosphatase magnesium-dependent 1 delta (PPM1D) is a negative regulator of p53 and promotes cell survival upon induction of genotoxic stress. Truncating mutations in the last exon of PPM1D lead to the production of a stable, enzymatically active protein and are commonly associated with clonal hematopoiesis. Using a transgenic mouse model, we demonstrate that truncated PPM1D reduces self-renewal of HSCs in basal conditions but promotes the development of aggressive AML after exposure to ionizing radiation. Inhibition of PPM1D suppressed the colony growth of leukemic stem and progenitor cells carrying the truncated PPM1D, and remarkably, it provided protection against irradiation-induced cell growth. Altogether, we demonstrate that truncated PPM1D affects HSC maintenance, disrupts normal hematopoiesis, and that its inhibition could be beneficial in the context of therapy-induced AML.
- MeSH
- akutní myeloidní leukemie * genetika MeSH
- mutace MeSH
- myši MeSH
- nádorový supresorový protein p53 * genetika MeSH
- poškození DNA MeSH
- proliferace buněk MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Cyclin-dependent kinases (CDKs) are master regulators of proliferation, and therefore they represent attractive targets for cancer therapy. Deve-lopment of selective CDK4/6 inhibitors including palbociclib revolutionized the treatment of advanced HR+/HER2- breast cancer. Inhibition of CDK4/6 leads to cell cycle arrest in G0/G1 phase and eventually to a permanent cell cycle exit called senescence. One of the main features of the senescence is an increased cell size. For many years, it was believed that the non-dividing cells simply continue to grow and as a result, they become excessively large. There is now emerging evidence that the increased cell size is a cause rather than consequence of the cell cycle arrest. This review aims to summarize recent advances in our understanding of senescence induction, in particular that resulting from treatment with CDK4/6 inhibitors.
