Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
nestr.
Gen CHEK2 kóduje kinázu CHK2, fosforylující řadu intracelulárních proteinů v odpovědi na poškození DNA. Patogenní, zárodečné mutace v CHEK2 zvyšují riziko vzniku karcinomu prsu a některých dalších nádorů. Analýza CHEK2 je v současnosti součástí genetické analýzy nádorové predispozice v ČR. V předchozích analýzách jsme mutace v CHEK2 nalezli u více jak 6,5% nemocných s ca prsu a/nebo ovaria a ukázali jsme, že většinu alterací tvoří varianty nejasného významu (VUS). Pro jejich funkční klasifikaci jsme vyvinuli unikátní systém založený na kvantifikaci fosforylace KAP1 katalyzované CHK2 v buněčné linii. Ve studii uzpůsobíme modelový systém pro vysokokapacitní analýzu a provedeme klasifikaci všech VUS v CHEK2 detekovaných spolupracujícími pracovišti u pacientů v ČR a zahraničí. Výsledky studie zvýší diagnostickou výtěžnost analýz nádorové predispozice a umožní charakterizovat pacienty s patogenními mutacemi CHEK2, což je základním předpokladem pro genetické poradenství v rodinách nosičů, stanovení rizika nádorů asociovaných s mutacemi v genu CHEK2 a racionalizaci preventivních opatření.; The CHEK2 gene codes for a checkpoint kinase CHK2 phosphorylating various intracellular proteins in response to DNA damage. Pathogenic germ-line CHEK2 mutations confer an increased breast and other cancer risk. CHEK2 mutation analysis is currently an obligatory procedure required for diagnostics in Czech hereditary cancer patients. We have shown that the prevalence of germline CHEK2 variants exceeds 6.5% in high-risk breast/ovarian Czech cancer patients and that the majority of found alterations represent variants of unknown significance (VUS). We developed a unique cell-based approach quantifying CHK2-mediated phosphorylation of KAP1 protein in vivo that enables reliable functional classification of CHEK2 VUS. Here we aim to optimize the assay for the high throughput analysis and classify all CHEK2 VUS identified by Czech and international collaborators. This study will enable clinical characterization of individuals carrying deleterious CHEK2 mutations, increasing diagnostic utility of CHEK2 analysis, improving risk estimation, and enabling optimal follow-up and prevention set-up.
- Klíčová slova
- breast cancer, karcinom prsu, varianta nejasného významu, hereditary cancer syndromes, functional analysis, dědičné nádorové syndromy, nádorová predispozice, CHEK2, CHK2 kináza, funkční ananlýza, CHEK2, CHK2 kinase, cancer predisposition, variant of uncertain significance,
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
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.
- Klíčová slova
- FAM110A,
- MeSH
- buněčné dělení fyziologie MeSH
- kaseinkinasy MeSH
- lidé MeSH
- nádory farmakoterapie MeSH
- proteinkinasy MeSH
- proteiny fyziologie MeSH
- Check Tag
- lidé MeSH
Cells are constantly challenged by DNA damage and protect their genome integrity by activation of an evolutionary conserved DNA damage response pathway (DDR). A central core of DDR is composed of a spatiotemporally ordered net of post-translational modifications, among which protein phosphorylation plays a major role. Activation of checkpoint kinases ATM/ATR and Chk1/2 leads to a temporal arrest in cell cycle progression (checkpoint) and allows time for DNA repair. Following DNA repair, cells re-enter the cell cycle by checkpoint recovery. Wip1 phosphatase (also called PPM1D) dephosphorylates multiple proteins involved in DDR and is essential for timely termination of the DDR. Here we have investigated how Wip1 is regulated in the context of the cell cycle. We found that Wip1 activity is downregulated by several mechanisms during mitosis. Wip1 protein abundance increases from G(1) phase to G(2) and declines in mitosis. Decreased abundance of Wip1 during mitosis is caused by proteasomal degradation. In addition, Wip1 is phosphorylated at multiple residues during mitosis, and this leads to inhibition of its enzymatic activity. Importantly, ectopic expression of Wip1 reduced γH2AX staining in mitotic cells and decreased the number of 53BP1 nuclear bodies in G(1) cells. We propose that the combined decrease and inhibition of Wip1 in mitosis decreases the threshold necessary for DDR activation and enables cells to react adequately even to modest levels of DNA damage encountered during unperturbed mitotic progression.
- MeSH
- DNA primery genetika MeSH
- fluorescenční protilátková technika MeSH
- fosforylace MeSH
- hmotnostní spektrometrie MeSH
- kontrolní body M fáze buněčného cyklu fyziologie MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- lidé MeSH
- malá interferující RNA genetika MeSH
- mitóza fyziologie MeSH
- nádorové buněčné linie MeSH
- poškození DNA * MeSH
- proteinfosfatasy metabolismus MeSH
- regulace genové exprese fyziologie MeSH
- signální transdukce fyziologie MeSH
- transfekce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The molecular mechanisms controlling microtubule formation in cells with non-centrosomal microtubular arrays are not yet fully understood. The key component of microtubule nucleation is gamma-tubulin. Although previous results suggested that tyrosine kinases might serve as regulators of gamma-tubulin function, their exact roles remain enigmatic. In the present study, we show that a pool of gamma-tubulin associates with detergent-resistant membranes in differentiating P19 embryonal carcinoma cells, which exhibit elevated expression of the Src family kinase Fyn (protein tyrosine kinase p59(Fyn)). Microtubule-assembly assays demonstrated that membrane-associated gamma-tubulin complexes are capable of initiating the formation of microtubules. Pretreatment of the cells with Src family kinase inhibitors or wortmannin blocked the nucleation activity of the gamma-tubulin complexes. Immunoprecipitation experiments revealed that membrane-associated gamma-tubulin forms complexes with Fyn and PI3K (phosphoinositide 3-kinase). Furthermore, in vitro kinase assays showed that p85alpha (regulatory p85alpha subunit of PI3K) serves as a Fyn substrate. Direct interaction of gamma-tubulin with the C-terminal Src homology 2 domain of p85alpha was determined by pull-down experiments and immunoprecipitation experiments with cells expressing truncated forms of p85alpha. The combined results suggest that Fyn and PI3K might take part in the modulation of membrane-associated gamma-tubulin activities.
- MeSH
- buněčná membrána metabolismus MeSH
- buněčné linie MeSH
- fosfatidylinositol-3-kinasy genetika metabolismus MeSH
- lidé MeSH
- mikrotubuly metabolismus MeSH
- myši MeSH
- podjednotky proteinů genetika metabolismus MeSH
- protoonkogenní proteiny c-fyn genetika metabolismus MeSH
- rekombinantní fúzní proteiny genetika metabolismus MeSH
- tubulin genetika metabolismus MeSH
- vazba proteinů MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
