Chemoresistance poses one of the most significant challenges of cancer therapy. Carboplatin (CbPt) is one of the most used chemotherapeutics in ovarian cancer (OVC) treatment. MRE11 constitutes a part of homologous recombination (HR), which is responsible for the repair of CbPt-induced DNA damage, particularly DNA crosslinks. The study's main aim was to address the role of HR in CbPt chemoresistance in OVC and to evaluate the possibility of overcoming CbPt chemoresistance by Mirin-mediated MRE11 inhibition in an OVC cell line. Lower expression of MRE11 was associated with better overall survival in a cohort of OVC patients treated with platinum drugs (TCGA dataset, P < 0.05). Using in vitro analyses, we showed that the high expression of HR genes drives the CbPt chemoresistance in our CbPt-resistant cell line model. Moreover, the HR inhibition by Mirin not only increased sensitivity to carboplatin (P < 0.05) but also rescued the sensitivity in the CbPt-resistant model (P < 0.05). Our results suggest that MRE11 inhibition with Mirin may represent a promising way to overcome OVC resistance. More therapy options will ultimately lead to better personalized cancer therapy and improvement of patients' survival.
- MeSH
- chemorezistence * genetika účinky léků MeSH
- homologní protein MRE11 * genetika MeSH
- karboplatina * farmakologie terapeutické užití MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- nádory vaječníků * farmakoterapie genetika MeSH
- poškození DNA účinky léků MeSH
- protinádorové látky farmakologie terapeutické užití MeSH
- regulace genové exprese u nádorů účinky léků MeSH
- rekombinační oprava DNA * účinky léků MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
MRE11 nuclease is a central player in signaling and processing DNA damage, and in resolving stalled replication forks. Here, we describe the identification and characterization of new MRE11 inhibitors MU147 and MU1409. Both compounds inhibit MRE11 nuclease more specifically and effectively than the relatively weak state-of-the-art inhibitor mirin. They also abrogate double-strand break repair mechanisms that rely on MRE11 nuclease activity, without impairing ATM activation. Inhibition of MRE11 also impairs nascent strand degradation of stalled replication forks and selectively affects BRCA2-deficient cells. Herein, we illustrate that our newly discovered compounds MU147 and MU1409 can be used as chemical probes to further explore the biological role of MRE11 and support the potential clinical relevance of pharmacological inhibition of this nuclease.
- MeSH
- homologní protein MRE11 * metabolismus antagonisté a inhibitory MeSH
- inhibitory enzymů * farmakologie chemie chemická syntéza MeSH
- lidé MeSH
- molekulární struktura MeSH
- objevování léků MeSH
- oprava DNA účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Doporučené postupy klinické péče o nosiče patogenních variant v klinicky relevantních genech predisponujících ke vzniku Lynchova syndromu a karcinomu kolorekta definují kroky primární a sekundární prevence, která by měla být osobám ve vysokém riziku vzniku dědičných nádorů v ČR poskytnuta. Tvorba doporučených postupů byla organizována pracovní skupinou onkogenetiky Společnosti lékařské genetiky a genomiky při České lékařské společnosti J. E. Purkyně ve spolupráci se zástupci onkologie, onkogynekologie a gastroenterologie. Doporučené postupy vycházejí z aktuálních doporučení National Comprehensive Cancer Network (NCCN), Evropské společnosti pro klinickou onkologii (ESMO) a zohledňují kapacitní možnosti našeho zdravotnictví.
The guidelines for clinical practice for carriers of pathogenic variants in clinically relevant genes predisposing to Lynch syndrome and colorectal cancer define the steps of primary and secondary prevention that should be provided to the individuals at high risk of developing hereditary cancer in the Czech Republic. The drafting of the guidelines was organized by the Oncogenetics Working Group of the Society for Medical Genetics and Genomics of J. E. Purkyně Czech Medical Society, in cooperation with representatives of oncology, oncogynecology, and gastroenterology. The guidelines are based on the current recommendations of the National Comprehensive Cancer Network (NCCN), European Society of Medical Oncology (ESMO) and take into account the capacity of the Czech healthcare system.
- MeSH
- adhezní molekula epiteliálních buněk genetika MeSH
- dědičné nepolypózní kolorektální nádory genetika MeSH
- genetická predispozice k nemoci * genetika MeSH
- kolorektální nádory * genetika MeSH
- mismatch repair endonukleáza PMS2 genetika MeSH
- MutL homolog 1 genetika MeSH
- směrnice pro lékařskou praxi jako téma MeSH
- zárodečné mutace genetika MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
- Geografické názvy
- Česká republika MeSH
Homologous recombination involves the formation of branched DNA molecules that may interfere with chromosome segregation. To resolve these persistent joint molecules, cells rely on the activation of structure-selective endonucleases (SSEs) during the late stages of the cell cycle. However, the premature activation of SSEs compromises genome integrity, due to untimely processing of replication and/or recombination intermediates. Here, we used a biochemical approach to show that the budding yeast SSEs Mus81 and Yen1 possess the ability to cleave the central recombination intermediate known as the displacement loop or D-loop. Moreover, we demonstrate that, consistently with previous genetic data, the simultaneous action of Mus81 and Yen1, followed by ligation, is sufficient to recreate the formation of a half-crossover precursor in vitro. Our results provide not only mechanistic explanation for the formation of a half-crossover, but also highlight the critical importance for precise regulation of these SSEs to prevent chromosomal rearrangements.
- MeSH
- crossing over (genetika) * MeSH
- DNA vazebné proteiny * metabolismus genetika MeSH
- endonukleasy * metabolismus genetika MeSH
- homologní rekombinace MeSH
- resolvasy Hollidayova spoje metabolismus genetika MeSH
- Saccharomyces cerevisiae - proteiny * metabolismus genetika MeSH
- Saccharomyces cerevisiae genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
The MRE11, RAD50, and NBN genes encode the MRN complex sensing DNA breaks and directing their repair. While carriers of biallelic germline pathogenic variants (gPV) develop rare chromosomal instability syndromes, the cancer risk in heterozygotes remains controversial. We performed a systematic review and meta-analysis of 53 studies in patients with different cancer diagnoses to better understand the cancer risk. We found an increased risk (odds ratio, 95% confidence interval) for gPV carriers in NBN for melanoma (7.14; 3.30-15.43), pancreatic cancer (4.03; 2.14-7.58), hematological tumors (3.42; 1.14-10.22), and prostate cancer (2.44, 1.84-3.24), but a low risk for breast cancer (1.29; 1.00-1.66) and an insignificant risk for ovarian cancer (1.53; 0.76-3.09). We found no increased breast cancer risk in carriers of gPV in RAD50 (0.93; 0.74-1.16; except of c.687del carriers) and MRE11 (0.87; 0.66-1.13). The secondary burden analysis compared the frequencies of gPV in MRN genes in patients from 150 studies with those in the gnomAD database. In NBN gPV carriers, this analysis additionally showed a high risk for brain tumors (5.06; 2.39-9.52), a low risk for colorectal (1.64; 1.26-2.10) and hepatobiliary (2.16; 1.02-4.06) cancers, and no risk for endometrial, and gastric cancer. The secondary burden analysis showed also a moderate risk for ovarian cancer (3.00; 1.27-6.08) in MRE11 gPV carriers, and no risk for ovarian and hepatobiliary cancers in RAD50 gPV carriers. These findings provide a robust clinical evidence of cancer risks to guide personalized clinical management in heterozygous carriers of gPV in the MRE11, RAD50, and NBN genes.
- MeSH
- DNA vazebné proteiny genetika MeSH
- enzymy opravy DNA genetika MeSH
- genetická predispozice k nemoci * MeSH
- homologní protein MRE11 * genetika MeSH
- hydrolasy působící na anhydridy kyselin * genetika MeSH
- jaderné proteiny * genetika MeSH
- lidé MeSH
- nádory * genetika MeSH
- proteiny buněčného cyklu * genetika MeSH
- zárodečné mutace * MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- systematický přehled MeSH
DNA double-strand breaks (DSBs), such as those produced by radiation and radiomimetics, are amongst the most toxic forms of cellular damage, in part because they involve extensive oxidative modifications at the break termini. Prior to completion of DSB repair, the chemically modified termini must be removed. Various DNA processing enzymes have been implicated in the processing of these dirty ends, but molecular knowledge of this process is limited. Here, we demonstrate a role for the metallo-β-lactamase fold 5'-3' exonuclease SNM1A in this vital process. Cells disrupted for SNM1A manifest increased sensitivity to radiation and radiomimetic agents and show defects in DSB damage repair. SNM1A is recruited and is retained at the sites of DSB damage via the concerted action of its three highly conserved PBZ, PIP box and UBZ interaction domains, which mediate interactions with poly-ADP-ribose chains, PCNA and the ubiquitinated form of PCNA, respectively. SNM1A can resect DNA containing oxidative lesions induced by radiation damage at break termini. The combined results reveal a crucial role for SNM1A to digest chemically modified DNA during the repair of DSBs and imply that the catalytic domain of SNM1A is an attractive target for potentiation of radiotherapy.
- MeSH
- DNA metabolismus genetika MeSH
- dvouřetězcové zlomy DNA * účinky záření MeSH
- enzymy opravy DNA * metabolismus genetika MeSH
- exodeoxyribonukleasy * metabolismus genetika MeSH
- lidé MeSH
- oprava DNA * MeSH
- proliferační antigen buněčného jádra metabolismus genetika MeSH
- proteiny buněčného cyklu MeSH
- ubikvitinace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Meiotic recombination is of central importance for the proper segregation of homologous chromosomes, but also for creating genetic diversity. It is initiated by the formation of double-strand breaks (DSBs) in DNA catalysed by evolutionarily conserved Spo11, together with additional protein partners. Difficulties in purifying the Spo11 protein have limited the characterization of its biochemical properties and of its interactions with other DSB proteins. In this study, we have purified fragments of Spo11 and show for the first time that Spo11 can physically interact with Mre11 and modulates its DNA binding, bridging, and nuclease activities. The interaction of Mre11 with Spo11 requires its far C-terminal region, which is in line with the severe meiotic phenotypes of various mre11 mutations located at the C-terminus. Moreover, calibrated ChIP for Mre11 shows that Spo11 promotes Mre11 recruitment to chromatin, independent of DSB formation. A mutant deficient in Spo11 interaction severely reduces the association of Mre11 with meiotic chromatin. Consistent with the reduction of Mre11 foci in this mutant, it strongly impedes DSB formation, leading to spore death. Our data provide evidence that physical interaction between Spo11 and Mre11, together with end-bridging, promote normal recruitment of Mre11 to hotspots and DSB formation.
- MeSH
- chromatin * metabolismus MeSH
- DNA vazebné proteiny metabolismus genetika MeSH
- dvouřetězcové zlomy DNA * MeSH
- endodeoxyribonukleasy * metabolismus genetika MeSH
- exodeoxyribonukleasy metabolismus genetika MeSH
- meióza * genetika MeSH
- mutace MeSH
- Saccharomyces cerevisiae - proteiny * metabolismus genetika MeSH
- Saccharomyces cerevisiae cytologie genetika metabolismus MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Targeting poly(ADP-ribose) glycohydrolase (PARG) is currently explored as a therapeutic approach to treat various cancer types, but we have a poor understanding of the specific genetic vulnerabilities that would make cancer cells susceptible to such a tailored therapy. Moreover, the identification of such vulnerabilities is of interest for targeting BRCA2;p53-deficient tumors that have acquired resistance to poly(ADP-ribose) polymerase inhibitors (PARPi) through loss of PARG expression. Here, by performing whole-genome CRISPR/Cas9 drop-out screens, we identify various genes involved in DNA repair to be essential for the survival of PARG;BRCA2;p53-deficient cells. In particular, our findings reveal EXO1 and FEN1 as major synthetic lethal interactors of PARG loss. We provide evidence for compromised replication fork progression, DNA single-strand break repair, and Okazaki fragment processing in PARG;BRCA2;p53-deficient cells, alterations that exacerbate the effects of EXO1/FEN1 inhibition and become lethal in this context. Since this sensitivity is dependent on BRCA2 defects, we propose to target EXO1/FEN1 in PARPi-resistant tumors that have lost PARG activity. Moreover, EXO1/FEN1 targeting may be a useful strategy for enhancing the effect of PARG inhibitors in homologous recombination-deficient tumors.
- MeSH
- "flap" endonukleasy genetika metabolismus terapeutické užití MeSH
- enzymy opravy DNA genetika MeSH
- exodeoxyribonukleasy genetika MeSH
- glykosidhydrolasy genetika metabolismus MeSH
- lidé MeSH
- nádorový supresorový protein p53 * genetika metabolismus MeSH
- nádory * farmakoterapie genetika MeSH
- oprava DNA MeSH
- PARP inhibitory farmakologie MeSH
- poškození DNA MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Upper tract urothelial carcinoma (UTUC) is the third most common malignancy associated with Lynch syndrome (LS). The current European urology guidelines recommend screening for LS in patients with UTUC up to the age of 60 years. In this study, we examined a cohort of patients with UTUC for potential association with LS in order to establish the sensitivity of current guidelines in detecting LS. A total of 180 patients with confirmed diagnosis of UTUC were enrolled in the study during a 12-year period (2010-2022). Loss of DNA-mismatch repair proteins (MMRp) expression was identified in 15/180 patients (8.3%). Germline analysis was eventually performed in 8 patients confirming LS in 5 patients (2.8%), including 4 germline mutations in MSH6 and 1 germline mutation in MSH2. LS-related UTUC included 3 females and 2 males, with a mean age of 66.2 years (median 71 years, range 46-75 years). Four of five LS patients (all with MSH6 mutation) were older than 65 years (mean age 71.3, median 72 years). Our findings indicate that LS-associated UTUCs can occur in patients with LS older than 60 years. In contrast to previous studies which used mainly highly pre-selected populations with already diagnosed LS, the most frequent mutation in our cohort involved MSH6 gene. All MSH6 mutation carriers were > 65 years, and UTUC was the first LS manifestation in 2/4 patients. Using current screening guidelines, a significant proportion of patients with LS-associated UTUC may be missed. We suggest universal immunohistochemical MMRp screening for all UTUCs, regardless of age and clinical history.
- MeSH
- dědičné nepolypózní kolorektální nádory * diagnóza genetika patologie MeSH
- karcinom z přechodných buněk * genetika MeSH
- lidé středního věku MeSH
- lidé MeSH
- mismatch repair endonukleáza PMS2 genetika MeSH
- MutL homolog 1 genetika MeSH
- nádory močového měchýře * MeSH
- oprava chybného párování bází DNA MeSH
- senioři MeSH
- urologie * MeSH
- zárodečné mutace MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Východiská: Lynchov syndróm (LS) je autozomálne dominantné dedičné ochorenie, ktoré sa prejavuje zvýšením rizika vzniku nádorových ochorení, a to predovšetkým kolorektálneho a endometriálneho karcinómu. Nedávne štúdie preukázali aj asociáciu medzi LS a nádorovým ochorením prsníka. Cieľom tejto štúdie je poukázať na možný výskyt prítomnosti mutácií v génoch asociovaných s LS u pacientov s rakovinou prsníka a na potrebu zahrnúť vyšetrenie Lynch asociovaných génov u pacientov s familiárnym a opakovaným výskytom rakoviny prsníka ako aj s výskytom ďalších Lynch asociovaných nádorových ochorení. Materiál a metódy: Analyzovali sme vzorky nádorového tkaniva od 78 pacientov s primárnym nádorom prsníka. U pacientov sme analyzovali panel génov asociovaný s rizikom vzniku rakoviny prsníka, pričom sme sa v rámci našej štúdie sústredili primárne na výskyt mutácií v mismatch-repair génoch. DNA izolovaná z nádorového tkaniva bola sekvenovaná pomocou metódy sekvenovania novej generácie (next generation sequencing – NGS) a podrobená analýze pomocou nástroja Ingenuity Variant Analysis. Na potvrdenie zárodočnej mutácie sme vyšetrili krvnú vzorku pacientky pomocou NGS. Výsledky: V rámci našej analýzy sa nám v nádorovom tkanive prsníka podarilo identifikovať variant v géne PMS2 u jednej pacientky. Prítomnosť mutácie naznačuje, že vzniknuté nádorové ochorenie môže byť následkom LS. Z hľadiska patogenity sa jednalo o pravdepodobne patogénny variant, nakoľko sme odhalili deléciu v exónovej oblasti, ktorá viedla k frameshift mutácii. Navyše sme identifikovali aj jednonukleotidové patogénne varianty v génoch TP53 a PIK3CA. Pre definitívne stanovenie diagnózy LS u pacientky sme vyšetrili krvnú vzorku, kde sme tiež identifikovali mutáciu génu PMS2. Záver: LS je u mnohých Lynch asociovaných nádorových ochorení poddiagnostikovaný. V prípade familiárneho výskytu rakoviny prsníka a ďalších Lynch asociovaných génov je však dôležité myslieť aj na možnú diagnózu LS a v prípade, že pacient spĺňa diagnostické kritéria, uskutočniť aj genetické vyšetrenie Lynch asociovaných génov.
Background: Lynch syndrome (LS) is an autosomal dominant inherited disorder which causes an increased risk of cancer, especially colorectal and endometrial carcinomas. Recent studies have shown an association between LS and breast cancer as well. The aim of our study is to highlight the possible presence of mutations in genes associated with LS in patients with breast cancer and the need to include the examination of Lynch-associated genes in patients with a family history of breast cancer as well as in patients with recurrent breast cancer, as well as with the occurrence of other Lynch-associated cancer. Materials and methods: We analyzed tumor tissue samples from 78 patients with primary breast cancer. Our samples were tested with a gene panel associated with the risk of developing breast cancer, while in our study we focused primarily on the occurrence of mutations in mismatch-repair genes. DNA isolated from tumor tissue was sequenced using next generation sequencing (NGS) and analyzed using the Ingenuity Variant Analysis tool. To confirm the germline mutation, we examined the patient‘s blood sample using NGS sequencing. Results: As a result of our analysis, we managed to identify a mutation in the PMS2 gene in one patient‘s breast tumor tissue. The presence of this mutation indicates that the resulting cancer may be a consequence of LS. As for pathogenicity, this was probably a pathogenic variant, as we detected deletions in the exon region, which led to frameshift mutation. Moreover, we also identified single-nucleotide pathogenic variants in the TP53 and PIK3CA genes. To definitively establish the diagnosis of LS in the patient, we examined a blood sample, where we also identified a mutation of the PMS2 gene. Conclusion: LS is underdiagnosed in many Lynch-associated cancers. However, in the case of a familial occurrence of breast cancer and other Lynch-associated genes, it is important to think about a possible diagnosis of LS and, if the patient meets the diagnostic criteria, to carry out a genetic examination of Lynch-associated genes.
- MeSH
- dědičné nepolypózní kolorektální nádory diagnóza genetika patologie MeSH
- genetická predispozice k nemoci MeSH
- lidé MeSH
- mismatch repair endonukleáza PMS2 genetika MeSH
- mutace MeSH
- nádory prsu * genetika MeSH
- pilotní projekty MeSH
- zárodečné mutace MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
