• MeSH
• chronická lymfatická leukemie genetika   MeSH
• DNA-dependentní DNA-polymerasy genetika   metabolismus   MeSH
• DNA-primasa genetika   metabolismus   MeSH
• extracelulární matrix metabolismus   patologie   MeSH
• geny p53 genetika   MeSH
• glioblastom metabolismus   patologie   MeSH
• pericyty metabolismus   patologie   MeSH
• protein BRCA1 genetika   metabolismus   MeSH
• Publikační typ
• souhrny MeSH

Reprogramming to pluripotency is associated with DNA damage and requires the functions of the BRCA1 tumor suppressor. Here, we leverage separation-of-function mutations in BRCA1/2 as well as the physical and/or genetic interactions between BRCA1 and its associated repair proteins to ascertain the relevance of homology-directed repair (HDR), stalled fork protection (SFP), and replication gap suppression (RGS) in somatic cell reprogramming. Surprisingly, loss of SFP and RGS is inconsequential for the transition to pluripotency. In contrast, cells deficient in HDR, but proficient in SFP and RGS, reprogram with reduced efficiency. Conversely, the restoration of HDR function through inactivation of 53bp1 rescues reprogramming in Brca1-deficient cells, and 53bp1 loss leads to elevated HDR and enhanced reprogramming in mouse and human cells. These results demonstrate that somatic cell reprogramming is especially dependent on repair of replication-associated double-strand breaks (DSBs) by the HDR activity of BRCA1 and BRCA2 and can be improved in the absence of 53BP1.

• MeSH
• 53BP1 * metabolismus   genetika   MeSH
• dvouřetězcové zlomy DNA * MeSH
• lidé MeSH
• myši MeSH
• oprava DNA * MeSH
• přeprogramování buněk * MeSH
• protein BRCA1 * metabolismus   genetika   MeSH
• rekombinační oprava DNA MeSH
• replikace DNA MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

The vast majority of epithelial ovarian cancer arises from tissues that are embryologically derived from the Müllerian Duct. Here, we demonstrate that a DNA methylation signature in easy-to-access Müllerian Duct-derived cervical cells from women with and without ovarian cancer (i.e. referred to as the Women's risk IDentification for Ovarian Cancer index or WID-OC-index) is capable of identifying women with an ovarian cancer in the absence of tumour DNA with an AUC of 0.76 and women with an endometrial cancer with an AUC of 0.81. This and the observation that the cervical cell WID-OC-index mimics the epigenetic program of those cells at risk of becoming cancerous in BRCA1/2 germline mutation carriers (i.e. mammary epithelium, fallopian tube fimbriae, prostate) further suggest that the epigenetic misprogramming of cervical cells is an indicator for cancer predisposition. This concept has the potential to advance the field of risk-stratified cancer screening and prevention.

• MeSH
• cervix uteri cytologie   metabolismus   MeSH
• epigenom MeSH
• epitel metabolismus   MeSH
• genetická predispozice k nemoci MeSH
• lidé MeSH
• metylace DNA * MeSH
• nádory vaječníků genetika   metabolismus   MeSH
• protein BRCA1 genetika   metabolismus   MeSH
• protein BRCA2 genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• pozorovací studie MeSH
• práce podpořená grantem MeSH

Genotoxic stress triggers a combined action of DNA repair and cell cycle checkpoint pathways. Protein phosphatase 2C delta (referred to as WIP1) is involved in timely inactivation of DNA damage response by suppressing function of p53 and other targets at chromatin. Here we show that WIP1 promotes DNA repair through homologous recombination. Loss or inhibition of WIP1 delayed disappearance of the ionizing radiation-induced 53BP1 foci in S/G2 cells and promoted cell death. We identify breast cancer associated protein 1 (BRCA1) as interactor and substrate of WIP1 and demonstrate that WIP1 activity is needed for correct dynamics of BRCA1 recruitment to chromatin flanking the DNA lesion. In addition, WIP1 dephosphorylates 53BP1 at Threonine 543 that was previously implicated in mediating interaction with RIF1. Finally, we report that inhibition of WIP1 allowed accumulation of DNA damage in S/G2 cells and increased sensitivity of cancer cells to a poly-(ADP-ribose) polymerase inhibitor olaparib. We propose that inhibition of WIP1 may increase sensitivity of BRCA1-proficient cancer cells to olaparib.

• MeSH
• 53BP1 metabolismus   MeSH
• antitumorózní látky farmakologie   MeSH
• apoptóza účinky léků   MeSH
• chemorezistence účinky léků   MeSH
• chromatin metabolismus   MeSH
• ftalaziny farmakologie   MeSH
• HEK293 buňky MeSH
• homologní rekombinace genetika   MeSH
• kontrolní body fáze G2 buněčného cyklu MeSH
• kontrolní body fáze S buněčného cyklu MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádory prsu metabolismus   MeSH
• oprava DNA genetika   fyziologie   MeSH
• PARP inhibitory farmakologie   MeSH
• piperaziny farmakologie   MeSH
• poškození DNA genetika   fyziologie   MeSH
• proliferace buněk účinky léků   MeSH
• protein BRCA1 metabolismus   MeSH
• proteinfosfatasa 2C antagonisté a inhibitory   genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The widespread use of next generation sequencing for clinical testing is detecting an escalating number of variants in noncoding regions of the genome. The clinical significance of the majority of these variants is currently unknown, which presents a significant clinical challenge. We have screened over 6,000 early-onset and/or familial breast cancer (BC) cases collected by the ENIGMA consortium for sequence variants in the 5' noncoding regions of BC susceptibility genes BRCA1 and BRCA2, and identified 141 rare variants with global minor allele frequency < 0.01, 76 of which have not been reported previously. Bioinformatic analysis identified a set of 21 variants most likely to impact transcriptional regulation, and luciferase reporter assays detected altered promoter activity for four of these variants. Electrophoretic mobility shift assays demonstrated that three of these altered the binding of proteins to the respective BRCA1 or BRCA2 promoter regions, including NFYA binding to BRCA1:c.-287C>T and PAX5 binding to BRCA2:c.-296C>T. Clinical classification of variants affecting promoter activity, using existing prediction models, found no evidence to suggest that these variants confer a high risk of disease. Further studies are required to determine if such variation may be associated with a moderate or low risk of BC.

• MeSH
• 5' nepřekládaná oblast MeSH
• aktivátorový protein specifický pro B-buňky metabolismus   MeSH
• faktor vázající CCAAT metabolismus   MeSH
• genetická predispozice k nemoci MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• nádorové buněčné linie MeSH
• nádory prsu genetika   MeSH
• promotorové oblasti (genetika) * MeSH
• protein BRCA1 chemie   genetika   metabolismus   MeSH
• protein BRCA2 chemie   genetika   metabolismus   MeSH
• vazba proteinů MeSH
• věk při počátku nemoci MeSH
• zárodečné mutace * MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Oncogene-evoked replication stress (RS) fuels genomic instability in diverse cancer types. Here we report that BRCA1, traditionally regarded a tumour suppressor, plays an unexpected tumour-promoting role in glioblastoma (GBM), safeguarding a protective response to supraphysiological RS levels. Higher BRCA1 positivity is associated with shorter survival of glioma patients and the abrogation of BRCA1 function in GBM enhances RS, DNA damage (DD) accumulation and impairs tumour growth. Mechanistically, we identify a novel role of BRCA1 as a transcriptional co-activator of RRM2 (catalytic subunit of ribonucleotide reductase), whereby BRCA1-mediated RRM2 expression protects GBM cells from endogenous RS, DD and apoptosis. Notably, we show that treatment with a RRM2 inhibitor triapine reproduces the BRCA1-depletion GBM-repressive phenotypes and sensitizes GBM cells to PARP inhibition. We propose that GBM cells are addicted to the RS-protective role of the BRCA1-RRM2 axis, targeting of which may represent a novel paradigm for therapeutic intervention in GBM.

• MeSH
• analýza přežití MeSH
• glioblastom genetika   metabolismus   patologie   MeSH
• karcinogeneze genetika   MeSH
• lidé MeSH
• myši inbrední BALB C MeSH
• myši nahé MeSH
• nádorové buněčné linie MeSH
• nádorové buňky kultivované MeSH
• nádory mozku genetika   metabolismus   patologie   MeSH
• protein BRCA1 genetika   metabolismus   MeSH
• regulace genové exprese u nádorů * MeSH
• replikace DNA genetika   MeSH
• retrospektivní studie MeSH
• ribonukleosiddifosfátreduktasa genetika   metabolismus   MeSH
• RNA interference MeSH
• transplantace heterologní MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Collisions between replication and transcription machineries represent a significant source of genomic instability. RECQ5 DNA helicase binds to RNA-polymerase (RNAP) II during transcription elongation and suppresses transcription-associated genomic instability. Here, we show that RECQ5 also associates with RNAPI and enforces the stability of ribosomal DNA arrays. We demonstrate that RECQ5 associates with transcription complexes in DNA replication foci and counteracts replication fork stalling in RNAPI- and RNAPII-transcribed genes, suggesting that RECQ5 exerts its genome-stabilizing effect by acting at sites of replication-transcription collisions. Moreover, RECQ5-deficient cells accumulate RAD18 foci and BRCA1-dependent RAD51 foci that are both formed at sites of interference between replication and transcription and likely represent unresolved replication intermediates. Finally, we provide evidence for a novel mechanism of resolution of replication-transcription collisions wherein the interaction between RECQ5 and proliferating cell nuclear antigen (PCNA) promotes RAD18-dependent PCNA ubiquitination and the helicase activity of RECQ5 promotes the processing of replication intermediates.

• MeSH
• biologické modely MeSH
• DNA řízené RNA-polymerasy metabolismus   MeSH
• DNA vazebné proteiny metabolismus   MeSH
• DNA-dependentní DNA-polymerasy metabolismus   MeSH
• elongace genetické transkripce MeSH
• fyziologický stres genetika   MeSH
• genetická transkripce * MeSH
• HEK293 buňky MeSH
• helikasy RecQ metabolismus   MeSH
• interakční proteinové domény a motivy MeSH
• lidé MeSH
• multienzymové komplexy metabolismus   MeSH
• otevřené čtecí rámce genetika   MeSH
• prekurzory RNA genetika   MeSH
• proliferační antigen buněčného jádra metabolismus   MeSH
• protein BRCA1 metabolismus   MeSH
• rekombinasa Rad51 metabolismus   MeSH
• replikace DNA * MeSH
• ribozomální DNA metabolismus   MeSH
• ubikvitinace MeSH
• ubikvitinligasy metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: The breast and ovarian cancer susceptibility gene BRCA1 encodes a multifunctional tumor suppressor protein BRCA1, which is involved in regulating cellular processes such as cell cycle, transcription, DNA repair, DNA damage response and chromatin remodeling. BRCA1 protein, located primarily in cell nuclei, interacts with multiple proteins and various DNA targets. It has been demonstrated that BRCA1 protein binds to damaged DNA and plays a role in the transcriptional regulation of downstream target genes. As a key protein in the repair of DNA double-strand breaks, the BRCA1-DNA binding properties, however, have not been reported in detail. RESULTS: In this study, we provided detailed analyses of BRCA1 protein (DNA-binding domain, amino acid residues 444-1057) binding to topologically constrained non-B DNA structures (e.g. cruciform, triplex and quadruplex). Using electrophoretic retardation assay, atomic force microscopy and DNA binding competition assay, we showed the greatest preference of the BRCA1 DNA-binding domain to cruciform structure, followed by DNA quadruplex, with the weakest affinity to double stranded B-DNA and single stranded DNA. While preference of the BRCA1 protein to cruciform structures has been reported previously, our observations demonstrated for the first time a preferential binding of the BRCA1 protein also to triplex and quadruplex DNAs, including its visualization by atomic force microscopy. CONCLUSIONS: Our discovery highlights a direct BRCA1 protein interaction with DNA. When compared to double stranded DNA, such a strong preference of the BRCA1 protein to cruciform and quadruplex structures suggests its importance in biology and may thus shed insight into the role of these interactions in cell regulation and maintenance.

• MeSH
• B-DNA chemie   metabolismus   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• protein BRCA1 chemie   metabolismus   MeSH
• proteinové domény MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Previously identified as a breast and ovarian cancer susceptibility gene, BRCA1 has gained major scientific interest as a potential prognostic and/or predictive marker for various tumors, including non-small-cell lung cancer (NSCLC), the leading cause of cancer related mortality worldwide. BRCA1 plays a central role in DNA damage response (DDR. It undergoes phosphorylation by various DDR kinases at different serine residues, of which ser1524 is known to be specifically phosphorylated by ATM in response to genotoxic stress. METHODS: We performed BRCA1 immunohistochemistry on several tissue microarrays (TMAs) of 113 early (I, II stage) and advanced (III, IV stage) NSCLCs, using MS110 antibody against the BRCA1 N-terminal and S1524 antibody against the phosphorylated form of BRCA1 protein at ser1524 (Abcam). Patients with III and IV stage disease were treated by adjuvant cisplatin-based chemotherapy. Staining results were correlated with overall survival (OS), disease free survival (DFS) and with the occurrence of brain metastases. RESULTS: BRCA1 S1524 nuclear positivity was significantly correlated with longer OS and DFS in stage I and II patients (P<0.05), while OS and DFS were shorter in S1524 positive stage III and IV patients (P<0.05). No significant correlation was found with brain metastases. CONCLUSION: The results show that BRCA1 phosphorylaton, at least in ser1524, differentiates the fate of early and advanced NSCLC as well as response to chemotherapy, but the underlying mechanisms are not completely understood. Detection of phosphorylated forms of BRCA1 might serve as a useful prognostic and predictive marker for patients with NSCLC.

• MeSH
• adjuvantní chemoterapie MeSH
• antitumorózní látky terapeutické užití   MeSH
• cisplatina terapeutické užití   MeSH
• fosforylace fyziologie   MeSH
• imunohistochemie MeSH
• kohortové studie MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové biomarkery metabolismus   MeSH
• nádory mozku farmakoterapie   metabolismus   sekundární   MeSH
• nádory plic farmakoterapie   metabolismus   MeSH
• nemalobuněčný karcinom plic farmakoterapie   metabolismus   sekundární   MeSH
• přežití po terapii bez příznaků nemoci MeSH
• prognóza MeSH
• protein BRCA1 metabolismus   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Alternative pre-mRNA splicing is a fundamental post-transcriptional regulatory mechanism. Cancer-specific misregulation of the splicing process may lead to formation of irregular alternative splicing variants (ASVs) with a potentially negative impact on cellular homeostasis. Alternative splicing of BRCA1 pre-mRNA can give rise to BRCA1 protein isoforms that possess dramatically altered biological activities compared with full-length wild-type BRCA1. During the screening of high-risk breast cancer (BC) families we ascertained numerous BRCA1 ASVs, however, their clinical significance for BC development is largely unknown. In this study, we examined the influence of the BRCA1Δ17-19 ASV, which lacks a portion of the BRCT domain, on DNA repair capacity using human MCF-7 BC cell clones with stably modified BRCA1 expression. Our results show that overexpression of BRCA1Δ17-19 impairs homologous recombination repair (sensitizes cells to mitomycin C), delays repair of ionizing radiation-induced DNA damage and dynamics of the ionizing radiation-induced foci (IRIF) formation, and undermines also the non-homologous end joining repair (NHEJ) activity. Mechanistically, BRCA1Δ17-19 cannot interact with the partner proteins Abraxas and CtIP, thus preventing interactions known to be critical for processing of DNA lesions. We propose that the observed inability of BRCA1Δ17-19 to functionally replace wtBRCA1 in repair of DNA double-strand breaks (DDSB) reflects impaired capacity to form the BRCA1-A and -C repair complexes. Our findings indicate that expression of BRCA1Δ17-19 may negatively influence genome stability by reducing the DDSB repair velocity, thereby contributing to enhanced probability of cancer development in the affected families.

• MeSH
• alternativní sestřih MeSH
• ionizující záření MeSH
• jaderné proteiny metabolismus   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• oprava DNA * MeSH
• poškození DNA účinky záření   MeSH
• protein BRCA1 genetika   metabolismus   MeSH
• terciární struktura proteinů MeSH
• transportní proteiny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH