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1.
Blood Adv ; 5(17): 3373-3376, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34477817

RESUMO

The molecular causes of myeloproliferative neoplasms (MPNs) have not yet been fully elucidated. Approximately 7% to 8% of the patients carry predisposing genetic germline variants that lead to driver mutations, which enhance JAK-STAT signaling. To identify additional predisposing genetic germline variants, we performed whole-exome sequencing in 5 families, each with parent-child or sibling pairs affected by MPNs and carrying the somatic JAK2 V617F mutation. In 4 families, we detected rare germline variants in known tumor predisposition genes of the DNA repair pathway, including the highly penetrant BRCA1 and BRCA2 genes. The identification of an underlying hereditary tumor predisposition is of major relevance for the individual patients as well as for their families in the context of therapeutic options and preventive care. Two patients with essential thrombocythemia or polycythemia vera experienced progression to acute myeloid leukemia, which may suggest a high risk of leukemic transformation in these familial MPNs. Our study demonstrates the relevance of genetic germline diagnostics in elucidating the causes of MPNs and suggests novel therapeutic options (eg, PARP inhibitors) in MPNs. Furthermore, we uncover a broader tumor spectrum upon the detection of a germline mutation in genes of the DNA repair pathway.


Assuntos
Leucemia Mieloide Aguda , Transtornos Mieloproliferativos , Proteína BRCA1/genética , Reparo do DNA/genética , Células Germinativas , Humanos , Janus Quinase 2/genética , Transtornos Mieloproliferativos/genética
2.
Talanta ; 234: 122698, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364494

RESUMO

The MWCNTs/Fe3O4@TMU-21 as a novel electrochemical sandwich-type genosensor was fabricated to detect the BRCA1 gene using the redox-cycling ferrocene functionalized reporter label probe (r-Fc-DNA). In the designed genosensor, the capture probe (cDNA) and r-Fc-DNA were used to detect the BRCA1 gene in sandwich-type genosensor, in which DNA sequences are well -hybridized with the BRCA1 gene (t-DNA). The cDNA was immobilized on the multiwall carbon nanotube and metal-organic framework with Fe3O4 nanoparticle core, which is the sensor platform. Target DNA was assayed by redox-recycling reporter probe (r-Fc-DNA) using the electro-catalytic activity of ferri/ferrocyanide, which results in significantly enhanced the oxidation peak current of r-Fc-DNA. The electrochemical redox cycling led to a high signal-to-noise ratio for gene assay. MWCNTs and Fe3O4@TMU-21 were applied to increase the platform conductivity and suitable binding of the recognition elements. This constructed genosensor plays an influential role in increasing the sensitivity of BRCA1 gene sequence recognition. So that under optimal conditions, this genosensor illustrated a wide linear range from 1.0×10-15 to 1.0×10-10 M with a detection limit of 0.57 × 10-15 M. Moreover, the genosensor exhibited high selectivity, stability, and reproducibility. The obtained recoveries (between 91 and 105%) of the BRCA1 gene assay in human blood samples satisfactory, which can be used for BRCA1 gene measurement in the laboratory.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Proteína BRCA1/genética , Genes BRCA1 , Ouro , Humanos , Limite de Detecção , Oxirredução , Reprodutibilidade dos Testes
3.
Nat Commun ; 12(1): 5016, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34408138

RESUMO

DNA damage prompts a diverse range of alterations to the chromatin landscape. The RNF168 E3 ubiquitin ligase catalyzes the mono-ubiquitination of histone H2A at lysine (K)13/15 (mUb-H2A), forming a binding module for DNA repair proteins. BRCA1 promotes homologous recombination (HR), in part, through its interaction with PALB2, and the formation of a larger BRCA1-PALB2-BRCA2-RAD51 (BRCA1-P) complex. The mechanism by which BRCA1-P is recruited to chromatin surrounding DNA breaks is unclear. In this study, we reveal that an RNF168-governed signaling pathway is responsible for localizing the BRCA1-P complex to DNA damage. Using mice harboring a Brca1CC (coiled coil) mutation that blocks the Brca1-Palb2 interaction, we uncovered an epistatic relationship between Rnf168- and Brca1CC alleles, which disrupted development, and reduced the efficiency of Palb2-Rad51 localization. Mechanistically, we show that RNF168-generated mUb-H2A recruits BARD1 through a BRCT domain ubiquitin-dependent recruitment motif (BUDR). Subsequently, BARD1-BRCA1 accumulate PALB2-RAD51 at DNA breaks via the CC domain-mediated BRCA1-PALB2 interaction. Together, these findings establish a series of molecular interactions that connect the DNA damage signaling and HR repair machinery.


Assuntos
Proteína BRCA1/metabolismo , Dano ao DNA , Proteína do Grupo de Complementação N da Anemia de Fanconi/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Proteína BRCA1/genética , Núcleo Celular/genética , Núcleo Celular/metabolismo , DNA/genética , DNA/metabolismo , Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Histonas/genética , Histonas/metabolismo , Humanos , Camundongos , Ligação Proteica , Transporte Proteico , Rad51 Recombinase/genética , Rad51 Recombinase/metabolismo , Reparo de DNA por Recombinação , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
4.
Int J Mol Sci ; 22(16)2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34445211

RESUMO

Several poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors are now in clinical use for tumours with defects in BReast CAncer genes BRCA1 or BRCA2 that result in deficient homologous recombination repair (HRR). Use of olaparib, niraparib or rucaparib for the treatment of high-grade serous ovarian cancer, including in the maintenance setting, has extended both progression free and overall survival for women with this malignancy. While different PARP inhibitors (PARPis) are mechanistically similar, differences are apparent in their chemical structures, toxicity profiles, PARP trapping abilities and polypharmacological landscapes. We have treated ovarian cancer cell line models of known BRCA status, including the paired cell lines PEO1 and PEO4, and UWB1.289 and UWB1.289+BRCA1, with five PARPis (olaparib, niraparib, rucaparib, talazoparib and veliparib) and observed differences between PARPis in both cell viability and cell survival. A cell line model of acquired resistance to veliparib showed increased resistance to the other four PARPis tested, suggesting that acquired resistance to one PARPi may not be able to be rescued by another. Lastly, as a proof of principle, HRR proficient ovarian cancer cells were sensitised to PARPis by depletion of BRCA1. In the future, guidelines will need to emerge to assist clinicians in matching specific PARPis to specific patients and tumours.


Assuntos
Proteína BRCA1 , Proteína BRCA2 , Modelos Biológicos , Mutação , Neoplasias Ovarianas , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Proteína BRCA2/genética , Proteína BRCA2/metabolismo , Linhagem Celular Tumoral , Feminino , Humanos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo
5.
Nat Commun ; 12(1): 4919, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34389725

RESUMO

BRCA1 or BRCA2 germline mutations predispose to breast, ovarian and other cancers. High-throughput sequencing of tumour genomes revealed that oncogene amplification and BRCA1/2 mutations are mutually exclusive in cancer, however the molecular mechanism underlying this incompatibility remains unknown. Here, we report that activation of ß-catenin, an oncogene of the WNT signalling pathway, inhibits proliferation of BRCA1/2-deficient cells. RNA-seq analyses revealed ß-catenin-induced discrete transcriptome alterations in BRCA2-deficient cells, including suppression of CDKN1A gene encoding the CDK inhibitor p21. This accelerates G1/S transition, triggering illegitimate origin firing and DNA damage. In addition, ß-catenin activation accelerates replication fork progression in BRCA2-deficient cells, which is critically dependent on p21 downregulation. Importantly, we find that upregulated p21 expression is essential for the survival of BRCA2-deficient cells and tumours. Thus, our work demonstrates that ß-catenin toxicity in cancer cells with compromised BRCA1/2 function is driven by transcriptional alterations that cause aberrant replication and inflict DNA damage.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Oncogenes/genética , Transcrição Genética/genética , beta Catenina/genética , Proteína BRCA1/deficiência , Proteína BRCA2/deficiência , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Sobrevivência Celular/genética , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Dano ao DNA , Feminino , Perfilação da Expressão Gênica/métodos , Células HeLa , Humanos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , RNA-Seq/métodos , beta Catenina/metabolismo
6.
FEBS J ; 288(15): 4439-4441, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34342144

RESUMO

In this special interview series, we profile members of The FEBS Journal editorial board to highlight their research focus, perspectives on the journal and future directions in their field. Hyunsook Lee is Professor at the Laboratory of Cancer Cell Biology at Seoul National University in Korea. She has served as an editorial board member of The FEBS Journal since 2018.


Assuntos
Biologia Celular/história , Genética Médica/história , Proteína BRCA1/genética , História do Século XX , História do Século XXI , República da Coreia
7.
Int J Mol Sci ; 22(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207612

RESUMO

The present limitations in the pathogenicity prediction of BRCA1 and BRCA2 (BRCA1/2) missense variants constitute an important problem with negative consequences for the diagnosis of hereditary breast and ovarian cancer. However, it has been proposed that the use of endophenotype predictions, i.e., computational estimates of the outcomes of functional assays, can be a good option to address this bottleneck. The application of this idea to the BRCA1/2 variants in the CAGI 5-ENIGMA international challenge has shown promising results. Here, we developed this approach, exploring the predictive performances of the regression models applied to the BRCA1/2 variants for which the values of the homology-directed DNA repair and saturation genome editing assays are available. Our results first showed that we can generate endophenotype estimates using a few molecular-level properties. Second, we show that the accuracy of these estimates is enough to obtain pathogenicity predictions comparable to those of many standard tools. Third, endophenotype-based predictions are complementary to, but do not outperform, those of a Random Forest model trained using variant pathogenicity annotations instead of endophenotype values. In summary, our results confirmed the usefulness of the endophenotype approach for the pathogenicity prediction of the BRCA1/2 missense variants, suggesting different options for future improvements.


Assuntos
Proteína BRCA1 , Proteína BRCA2 , Simulação por Computador , Modelos Biológicos , Mutação de Sentido Incorreto , Neoplasias Ovarianas , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Proteína BRCA2/genética , Proteína BRCA2/metabolismo , Feminino , Humanos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo
8.
BMC Med Res Methodol ; 21(1): 155, 2021 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-34325649

RESUMO

BACKGROUND: Linking independent sources of data describing the same individuals enable innovative epidemiological and health studies but require a robust record linkage approach. We describe a hybrid record linkage process to link databases from two independent ongoing French national studies, GEMO (Genetic Modifiers of BRCA1 and BRCA2), which focuses on the identification of genetic factors modifying cancer risk of BRCA1 and BRCA2 mutation carriers, and GENEPSO (prospective cohort of BRCAx mutation carriers), which focuses on environmental and lifestyle risk factors. METHODS: To identify as many as possible of the individuals participating in the two studies but not registered by a shared identifier, we combined probabilistic record linkage (PRL) and supervised machine learning (ML). This approach (named "PRL + ML") combined together the candidate matches identified by both approaches. We built the ML model using the gold standard on a first version of the two databases as a training dataset. This gold standard was obtained from PRL-derived matches verified by an exhaustive manual review. Results The Random Forest (RF) algorithm showed a highest recall (0.985) among six widely used ML algorithms: RF, Bagged trees, AdaBoost, Support Vector Machine, Neural Network. Therefore, RF was selected to build the ML model since our goal was to identify the maximum number of true matches. Our combined linkage PRL + ML showed a higher recall (range 0.988-0.992) than either PRL (range 0.916-0.991) or ML (0.981) alone. It identified 1995 individuals participating in both GEMO (6375 participants) and GENEPSO (4925 participants). CONCLUSIONS: Our hybrid linkage process represents an efficient tool for linking GEMO and GENEPSO. It may be generalizable to other epidemiological studies involving other databases and registries.


Assuntos
Neoplasias da Mama , Proteína BRCA1/genética , Proteína BRCA2/genética , Estudos de Coortes , Bases de Dados Factuais , Feminino , Predisposição Genética para Doença , Humanos , Mutação , Estudos Prospectivos , Risco
9.
Mol Cell ; 81(15): 3128-3144.e7, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34216544

RESUMO

Mutations in BRCA1 or BRCA2 (BRCA) is synthetic lethal with poly(ADP-ribose) polymerase inhibitors (PARPi). Lethality is thought to derive from DNA double-stranded breaks (DSBs) necessitating BRCA function in homologous recombination (HR) and/or fork protection (FP). Here, we report instead that toxicity derives from replication gaps. BRCA1- or FANCJ-deficient cells, with common repair defects but distinct PARPi responses, reveal gaps as a distinguishing factor. We further uncouple HR, FP, and fork speed from PARPi response. Instead, gaps characterize BRCA-deficient cells, are diminished upon resistance, restored upon resensitization, and, when exposed, augment PARPi toxicity. Unchallenged BRCA1-deficient cells have elevated poly(ADP-ribose) and chromatin-associated PARP1, but aberrantly low XRCC1 consistent with defects in backup Okazaki fragment processing (OFP). 53BP1 loss resuscitates OFP by restoring XRCC1-LIG3 that suppresses the sensitivity of BRCA1-deficient cells to drugs targeting OFP or generating gaps. We highlight gaps as a determinant of PARPi toxicity changing the paradigm for synthetic lethal interactions.


Assuntos
Proteína BRCA1/genética , Replicação do DNA/efeitos dos fármacos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Animais , Linhagem Celular , Cisplatino/farmacologia , DNA/genética , DNA/metabolismo , DNA de Cadeia Simples/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Proteínas de Grupos de Complementação da Anemia de Fanconi/genética , Recombinação Homóloga/efeitos dos fármacos , Humanos , Camundongos Endogâmicos NOD , RNA Helicases/genética , Rad51 Recombinase/genética , Proteína de Replicação A/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética
10.
Breast Cancer Res Treat ; 189(2): 363-375, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34287743

RESUMO

PURPOSE: Inherited variants in the cancer susceptibility genes, BRCA1 and BRCA2 account for up to 5% of breast cancers. Multiple gene expression studies have analysed gene expression patterns that maybe associated with BRCA12 pathogenic variant status; however, results from these studies lack consensus. These studies have focused on the differences in population means to identified genes associated with BRCA1/2-carriers with little consideration for gene expression variability, which is also under genetic control and is a feature of cellular function. METHODS: We measured differential gene expression variability in three of the largest familial breast cancer datasets and a 2116 breast cancer meta-cohort. Additionally, we used RNA in situ hybridisation to confirm expression variability of EN1 in an independent cohort of more than 500 breast tumours. RESULTS: BRCA1-associated breast tumours exhibited a 22.8% (95% CI 22.3-23.2) increase in transcriptome-wide gene expression variability compared to BRCAx tumours. Additionally, 40 genes were associated with BRCA1-related breast cancers that had ChIP-seq data suggestive of enriched EZH2 binding. Of these, two genes (EN1 and IGF2BP3) were significantly variable in both BRCA1-associated and basal-like breast tumours. RNA in situ analysis of EN1 supported a significant (p = 6.3 × 10-04) increase in expression variability in BRCA1-associated breast tumours. CONCLUSION: Our novel results describe a state of increased gene expression variability in BRCA1-related and basal-like breast tumours. Furthermore, genes with increased variability may be driven by changes in DNA occupancy of epigenetic effectors. The variation in gene expression is replicable and led to the identification of novel associations between genes and disease phenotypes.


Assuntos
Neoplasias da Mama , Genes BRCA1 , Proteína BRCA1/genética , Neoplasias da Mama/genética , Feminino , Expressão Gênica , Perfilação da Expressão Gênica , Genes BRCA2 , Predisposição Genética para Doença , Humanos
11.
Cancer Treat Rev ; 99: 102256, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34261032

RESUMO

The evaluation of the homologous recombination repair (HRR) status is emerging as a predictive tumor agnostic biomarker for poly (ADP-ribose) polymerase (PARP) inhibition across different tumor types and testing for HRR-signature is currently a developing area with promising therapeutic implications. Treatment with PARP inhibitors (PARPi) either as single agent or in combination with chemotherapy have shown so far limited activity in patients with thoracic malignancies. A deeper understanding of the biological background underlying HRR-deficient tumors, along with the recent advent of new effective targeted and immunotherapeutic agents, prompted the design of a new generation of clinical trials investigating novel PARPi-combinations in patients with lung cancer as well as malignant pleural mesothelioma. In this review we briefly summarize the biological basis of the DNA damage response pathway inhibition and provide an updated and detailed overview of clinical trials testing different PARPi-combinations strategies in patients with thoracic malignancies.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Neoplasias Torácicas/tratamento farmacológico , Proteína BRCA1/genética , Proteína BRCA2/genética , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Ensaios Clínicos Fase I como Assunto , Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Fase III como Assunto , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Mesotelioma Maligno/tratamento farmacológico , Neoplasias Pleurais/tratamento farmacológico , Inibidores de Poli(ADP-Ribose) Polimerases/administração & dosagem , Ensaios Clínicos Controlados Aleatórios como Assunto , Reparo de DNA por Recombinação , Neoplasias Torácicas/genética
12.
J Cancer Res Clin Oncol ; 147(10): 2935-2944, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34254208

RESUMO

PURPOSE: BRCA1/2 screening for all triple-negative breast cancer (TNBC) patients younger than 60 years may still be an economic burden in China. Further evidences that include incidence and outcome of BRCA1/2 pathogenic variants (PV) screened based on younger age or family history (FH) are worth discussing for improving the cost-effectiveness of BRCA1/2 testing in Chinese TNBC. We aimed to investigate the prevalence of germline and tumor BRCA1/2 PV based on age screening in Chinese TNBC patients. METHODS: Paired blood and tumor DNA from 124 unselected Chinese TNBC patients with less than or equal to 55 years were collected and analyzed for BRCA1/2 PV. Clinicopathological characteristics including age at diagnosis, FH and follow-up data were collected for further analysis. RESULTS: The entire frequency of germline and tumor BRCA1/2 PV was 21.0 and 25%, respectively. Among them, 20 (16.1%) germline and 5 (4.0%) somatic BRCA1/2 single-nucleotide variant/insertion/deletions were found by NGS testing, 6 (4.8%) BRCA1 large genomic rearrangements were detected in blood DNA by MPLA. There was significant correlation between FH of HBOC and germline BRCA1/2 PVs among these patients. Patients with tumor BRCA1/2 PVs had significant improvements than non-carriers in PFS (p = 0.047). No significant impacts were found between various mutation status in OS outcomes. No significant differences were found between BRCA1 or BRCA2 and non-carriers in PFS or OS. CONCLUSION: There is a high incidence of germline and tumor BRCA1/2 PVs in Chinese TNBC patients with less than or equal to 55 years old. Tumor BRCA1/2 PV carriers showed an improved survival outcome. Our results suggest that BRCA1/2 PVs testing addressed within each specific clinical scenario could be more cost-effective for patients.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Proteína BRCA1/genética , Proteína BRCA2/genética , Biomarcadores Tumorais/genética , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Neoplasias de Mama Triplo Negativas/patologia , Adolescente , Adulto , China/epidemiologia , Feminino , Seguimentos , Testes Genéticos , Humanos , Pessoa de Meia-Idade , Prognóstico , Taxa de Sobrevida , Neoplasias de Mama Triplo Negativas/epidemiologia , Neoplasias de Mama Triplo Negativas/genética , Adulto Jovem
13.
Ann Surg Oncol ; 28(10): 5657-5662, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34296361

RESUMO

BACKGROUND: Nipple-sparing mastectomy (NSM) is now routinely offered to BRCA mutation carriers for risk reduction. We assessed the rates of ipsilateral cancer events after prophylactic and therapeutic NSM in BRCA1 and BRCA2 mutation carriers. METHODS: BRCA1 and BRCA2 mutation carriers undergoing NSM from October 2007 to June 2019 were identified in a single-institution prospective database, with variants of unknown significance being excluded. Patient, tumor, and outcomes data were collected. Follow-up analysis was by cumulative breast-years (total years of follow-up of each breast) and woman-years (total years of follow-up of each woman). RESULTS: Overall, 307 BRCA1 and BRCA2 mutation carriers (160 BRCA1, mean age 41.4 years [range 21-65]; and 147 BRCA2, mean age 43.8 years [range 23-65]) underwent 607 NSMs, with a median follow-up of 42 months (range 1-143). 388 bilateral prophylactic NSMs had 744 cumulative woman-years of follow-up, with no new cancers seen (< 0.0013 new cancers per woman-years); 251 BRCA1 prophylactic NSMs had 1034 cumulative breast-years of follow-up, with no new ipsilateral cancers seen (< 0.0010 per breast-year); 66 BRCA1 therapeutic NSMs had 328 cumulative breast-years of follow-up, with one ipsilateral cancer recurrence not directly involving the nipple or areola (0.0030 per breast-year); 237 BRCA2 prophylactic NSMs had 926 cumulative breast-years of follow-up, with no new ipsilateral cancers seen (< 0.0011 per breast-year); and 53 BRCA2 therapeutic NSMs had 239 cumulative breast-years of follow-up, with two ipsilateral recurrent cancers, neither of which directly involved the nipple or areola (0.0084 per breast-year). CONCLUSIONS: The risk of new ipsilateral breast cancers is extremely low after NSM in BRCA1 and BRCA2 mutation carriers. NSM is an effective risk-reducing strategy for BRCA gene mutations.


Assuntos
Neoplasias da Mama , Mastectomia Profilática , Adulto , Idoso , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Neoplasias da Mama/prevenção & controle , Neoplasias da Mama/cirurgia , Feminino , Humanos , Mastectomia , Pessoa de Meia-Idade , Mutação , Recidiva Local de Neoplasia , Mamilos/cirurgia , Adulto Jovem
14.
Nat Commun ; 12(1): 4126, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-34226554

RESUMO

Double stranded DNA Breaks (DSB) that occur in highly transcribed regions of the genome are preferentially repaired by homologous recombination repair (HR). However, the mechanisms that link transcription with HR are unknown. Here we identify a critical role for DHX9, a RNA helicase involved in the processing of pre-mRNA during transcription, in the initiation of HR. Cells that are deficient in DHX9 are impaired in the recruitment of RPA and RAD51 to sites of DNA damage and fail to repair DSB by HR. Consequently, these cells are hypersensitive to treatment with agents such as camptothecin and Olaparib that block transcription and generate DSB that specifically require HR for their repair. We show that DHX9 plays a critical role in HR by promoting the recruitment of BRCA1 to RNA as part of the RNA Polymerase II transcription complex, where it facilitates the resection of DSB. Moreover, defects in DHX9 also lead to impaired ATR-mediated damage signalling and an inability to restart DNA replication at camptothecin-induced DSB. Together, our data reveal a previously unknown role for DHX9 in the DNA Damage Response that provides a critical link between RNA, RNA Pol II and the repair of DNA damage by homologous recombination.


Assuntos
Proteína BRCA1/metabolismo , RNA Helicases DEAD-box/metabolismo , DNA , Recombinação Homóloga , Proteínas de Neoplasias/metabolismo , RNA , Proteína BRCA1/genética , RNA Helicases DEAD-box/genética , Dano ao DNA , DNA Helicases , Reparo do DNA , Replicação do DNA , Proteínas de Ligação a DNA/metabolismo , Humanos , Ftalazinas , Piperazinas , RNA Helicases , RNA Mensageiro , Rad51 Recombinase , Reparo de DNA por Recombinação
15.
Breast Cancer Res Treat ; 189(2): 533-539, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34196900

RESUMO

PURPOSE: Mutations in hereditary breast cancer genes play an important role in the risk for cancer. METHODS: Cancer susceptibility genes were sequenced in 664 unselected breast cancer cases from Guatemala. Variants were annotated with ClinVar and VarSome. RESULTS: A total of 73 out of 664 subjects (11%) had a pathogenic variant in a high or moderate penetrance gene. The most frequently mutated genes were BRCA1 (37/664, 5.6%) followed by BRCA2 (15/664, 2.3%), PALB2 (5/664, 0.8%), and TP53 (5/664, 0.8%). Pathogenic variants were also detected in the moderate penetrance genes ATM, BARD1, CHEK2, and MSH6. The high ratio of BRCA1/BRCA2 mutations is due to two potential founder mutations: BRCA1 c.212 + 1G > A splice mutation (15 cases) and BRCA1 c.799delT (9 cases). Cases with pathogenic mutations had a significantly earlier age at diagnosis (45 vs 51 years, P < 0.001), are more likely to have had diagnosis before menopause, and a higher percentage had a relative with any cancer (51% vs 37%, P = 0.038) or breast cancer (33% vs 15%, P < 0.001). CONCLUSIONS: Hereditary breast cancer mutations were observed among Guatemalan women, and these women are more likely to have early age at diagnosis and family history of cancer. These data suggest the use of genetic testing in breast cancer patients and those at high risk as part of a strategy to reduce breast cancer mortality in Guatemala.


Assuntos
Neoplasias da Mama , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Feminino , Genes BRCA2 , Células Germinativas , Guatemala , Humanos
18.
Mol Biol (Mosk) ; 55(3): 412-421, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34097676

RESUMO

Molecular profiling of tumors may provide promising options for personalized treatment. We have examined the spectrum of germline and somatic mutations in 23 breast cancers (ВС) of various molecular subtypes, including tumors 1) with expression of estrogen, progesterone and/or epidermal growth factor receptor HER2/neu, and 2) with a triple negative phenotype. Genomic DNA specimens were isolated from archived tumor and normal tissue samples and subjected to targeted sequencing of the coding regions of 25 cancer-associated genes with a mean coverage of x 1000. In the triple negative subtype of ВС, the pathogenic germline mutations BRCA1 c.66_67delAG (185delAG) and BRCA1 c.3226_3227AG (3347delAG) were detected, while the germline mutation BRCA2 658_659del (886delGT) was found in patients with positive receptor staining. Mutations in BRCAl/2 were overrepresented by frequency (80%), pointing at common loss of heterozygosity affecting the normal allele. Somatic mutations in the TP53 gene were found in 7/10 (70%) patients with the triple negative subtype of ВС and in 3/13 (23%) in the group with positive receptor staining. Additionally, in both groups of patients, somatic mutations of the PTEN, MSH2, MSH6, and MUTYH genes were detected.


Assuntos
Neoplasias da Mama , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Feminino , Predisposição Genética para Doença , Células Germinativas , Mutação em Linhagem Germinativa , Humanos , Mutação
19.
BMC Med Inform Decis Mak ; 21(1): 180, 2021 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-34090422

RESUMO

BACKGROUND: Women with pathogenic BRCA1 and BRCA2 mutations possess a high risk of developing breast and ovarian cancer. They face difficult choices when considering preventive options. This study presents the development process of the first decision aids to support this complex decision-making process in the German healthcare system. METHODS: A six-step development process based on the International Patient Decision Aid Standards was used, including a systematic literature review of existing decision aids, a topical medical literature review, preparation of the decision aids, focus group discussions with women with BRCA1/2 mutations, internal and external reviews by clinical and self-help experts, and user tests. All reviews were followed by iterative revisions. RESULTS: No existing decision aids were transferable to the German setting. The medical research revealed a need to develop separate decision aids for women with BRCA1/2 mutations (A) without a history of cancer (previvors) and (B) with a history of unilateral breast cancer (survivors). The focus group discussions confirmed a high level of approval for the decision aids from both target groups. Additionally, previvors requested more information on risk-reducing breast surgery, risk-reducing removal of both ovaries and Fallopian tubes, and psychological aspects; survivors especially wanted more information on breast cancer on the affected side (e.g. biological parameters, treatment, and risk of recurrence). CONCLUSIONS: In a structured process, two target-group-specific DAs for previvors/survivors with BRCA1/2 mutations were developed to support decision-making on risk-adapted preventive options. These patient-oriented tools offer an important addition to existing specialist medical care in Germany.


Assuntos
Neoplasias da Mama , Técnicas de Apoio para a Decisão , Neoplasias Ovarianas , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Neoplasias da Mama/prevenção & controle , Feminino , Genes BRCA1 , Genes BRCA2 , Predisposição Genética para Doença , Alemanha , Humanos , Mutação , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/prevenção & controle
20.
Nat Commun ; 12(1): 3542, 2021 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-34112789

RESUMO

R-loop structures act as modulators of physiological processes such as transcription termination, gene regulation, and DNA repair. However, they can cause transcription-replication conflicts and give rise to genomic instability, particularly at telomeres, which are prone to forming DNA secondary structures. Here, we demonstrate that BRCA1 binds TERRA RNA, directly and physically via its N-terminal nuclear localization sequence, as well as telomere-specific shelterin proteins in an R-loop-, and a cell cycle-dependent manner. R-loop-driven BRCA1 binding to CpG-rich TERRA promoters represses TERRA transcription, prevents TERRA R-loop-associated damage, and promotes its repair, likely in association with SETX and XRN2. BRCA1 depletion upregulates TERRA expression, leading to overly abundant TERRA R-loops, telomeric replication stress, and signs of telomeric aberrancy. Moreover, BRCA1 mutations within the TERRA-binding region lead to an excess of TERRA-associated R-loops and telomeric abnormalities. Thus, normal BRCA1/TERRA binding suppresses telomere-centered genome instability.


Assuntos
Proteína BRCA1/metabolismo , Dano ao DNA/genética , Estruturas R-Loop , RNA Longo não Codificante/metabolismo , Telômero/metabolismo , Proteína BRCA1/genética , Ciclo Celular/genética , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Cromatografia Líquida , Ilhas de CpG , DNA Helicases/metabolismo , Exorribonucleases/metabolismo , Humanos , Hibridização in Situ Fluorescente , Espectrometria de Massas , Enzimas Multifuncionais/metabolismo , Mutação , Regiões Promotoras Genéticas , Ligação Proteica , Estruturas R-Loop/genética , RNA Helicases/metabolismo , RNA Longo não Codificante/genética , RNA Interferente Pequeno , Telômero/genética
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