RESUMO
Histone lysine methyltransferase 2D (KMT2D) is the most frequently mutated epigenetic modifier in head and neck squamous cell carcinoma (HNSCC). However, the role of KMT2D in HNSCC tumorigenesis and whether its mutations confer any therapeutic vulnerabilities remain unknown. Here we show that KMT2D deficiency promotes HNSCC growth through increasing glycolysis. Additionally, KMT2D loss decreases the expression of Fanconi Anemia (FA)/BRCA pathway genes under glycolytic inhibition. Mechanistically, glycolytic inhibition facilitates the occupancy of KMT2D to the promoter/enhancer regions of FA genes. KMT2D loss reprograms the epigenomic landscapes of FA genes by transiting their promoter/enhancer states from active to inactive under glycolytic inhibition. Therefore, combining the glycolysis inhibitor 2-DG with DNA crosslinking agents or poly (ADP-ribose) polymerase (PARP) inhibitors preferentially inhibits tumor growth of KMT2D-deficient mouse HNSCC and patient-derived xenografts (PDXs) harboring KMT2D-inactivating mutations. These findings provide an epigenomic basis for developing targeted therapies for HNSCC patients with KMT2D-inactivating mutations.
Assuntos
Glicólise , Carcinoma de Células Escamosas de Cabeça e Pescoço , Animais , Humanos , Camundongos , Glicólise/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/deficiência , Proteína BRCA2/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/deficiência , Histona-Lisina N-Metiltransferase/metabolismo , Histona-Lisina N-Metiltransferase/genética , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/patologia , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Regulação Neoplásica da Expressão Gênica , Ensaios Antitumorais Modelo de Xenoenxerto , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Feminino , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Transdução de Sinais , Regiões Promotoras Genéticas/genética , Proteína de Leucina Linfoide-MieloideRESUMO
Clinical success with poly (ADP-ribose) polymerase inhibitors (PARPi) is impeded by inevitable resistance and associated cytotoxicity. Depletion of Amplified in Liver Cancer 1 (ALC1), a chromatin-remodeling enzyme, can overcome these limitations by hypersensitizing BReast CAncer genes 1/2 (BRCA1/2) mutant cells to PARPi. Here, we demonstrate that PARPi hypersensitivity upon ALC1 loss is reliant on its role in promoting the repair of chromatin buried abasic sites. We show that ALC1 enhances the ability of the abasic site processing enzyme, Apurinic/Apyrimidinic endonuclease 1 (APE1) to cleave nucleosome-occluded abasic sites. However, unrepaired abasic sites in ALC1-deficient cells are readily accessed by APE1 at the nucleosome-free replication forks. APE1 cleavage leads to fork breakage and trapping of PARP1/2 upon PARPi treatment, resulting in hypersensitivity. Collectively, our studies reveal how cells overcome the chromatin barrier to repair abasic lesions and uncover cleavage of abasic sites as a mechanism to overcome limitations of PARPi.
Assuntos
Proteína BRCA1 , Proteína BRCA2 , Reparo do DNA , DNA Liase (Sítios Apurínicos ou Apirimidínicos) , Inibidores de Poli(ADP-Ribose) Polimerases , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Humanos , Linhagem Celular Tumoral , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/deficiência , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/genética , Proteína BRCA2/deficiência , Reparo do DNA/efeitos dos fármacos , Poli(ADP-Ribose) Polimerase-1/metabolismo , Poli(ADP-Ribose) Polimerase-1/genética , Feminino , Cromatina/metabolismo , Mutação , Dano ao DNA/efeitos dos fármacos , Neoplasias da Mama/genética , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Replicação do DNA/efeitos dos fármacos , Nucleossomos/metabolismo , DNA Helicases , Proteínas de Ligação a DNARESUMO
PURPOSE: The purpose of this study was to evaluate RB1 expression and survival across ovarian carcinoma histotypes and how co-occurrence of BRCA1 or BRCA2 (BRCA) alterations and RB1 loss influences survival in tubo-ovarian high-grade serous carcinoma (HGSC). EXPERIMENTAL DESIGN: RB1 protein expression was classified by immunohistochemistry in ovarian carcinomas of 7,436 patients from the Ovarian Tumor Tissue Analysis consortium. We examined RB1 expression and germline BRCA status in a subset of 1,134 HGSC, and related genotype to overall survival (OS), tumor-infiltrating CD8+ lymphocytes, and transcriptomic subtypes. Using CRISPR-Cas9, we deleted RB1 in HGSC cells with and without BRCA1 alterations to model co-loss with treatment response. We performed whole-genome and transcriptome data analyses on 126 patients with primary HGSC to characterize tumors with concurrent BRCA deficiency and RB1 loss. RESULTS: RB1 loss was associated with longer OS in HGSC but with poorer prognosis in endometrioid ovarian carcinoma. Patients with HGSC harboring both RB1 loss and pathogenic germline BRCA variants had superior OS compared with patients with either alteration alone, and their median OS was three times longer than those without pathogenic BRCA variants and retained RB1 expression (9.3 vs. 3.1 years). Enhanced sensitivity to cisplatin and paclitaxel was seen in BRCA1-altered cells with RB1 knockout. Combined RB1 loss and BRCA deficiency correlated with transcriptional markers of enhanced IFN response, cell-cycle deregulation, and reduced epithelial-mesenchymal transition. CD8+ lymphocytes were most prevalent in BRCA-deficient HGSC with co-loss of RB1. CONCLUSIONS: Co-occurrence of RB1 loss and BRCA deficiency was associated with exceptionally long survival in patients with HGSC, potentially due to better treatment response and immune stimulation.
Assuntos
Proteína BRCA1 , Proteína BRCA2 , Cistadenocarcinoma Seroso , Neoplasias Ovarianas , Proteínas de Ligação a Retinoblastoma , Humanos , Feminino , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/imunologia , Neoplasias Ovarianas/patologia , Proteína BRCA2/genética , Proteína BRCA2/deficiência , Proteína BRCA1/genética , Proteína BRCA1/deficiência , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/patologia , Cistadenocarcinoma Seroso/mortalidade , Cistadenocarcinoma Seroso/imunologia , Proteínas de Ligação a Retinoblastoma/genética , Prognóstico , Ubiquitina-Proteína Ligases/genética , Gradação de Tumores , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Pessoa de Meia-Idade , Mutação em Linhagem Germinativa , Regulação Neoplásica da Expressão Gênica , Idoso , Biomarcadores Tumorais/genética , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismoRESUMO
More than 20% of metastatic prostate cancer carries genomic defects involving DNA damage repair pathways, mainly in homologous recombination repair-related genes. The recent approval of olaparib has paved the way to precision medicine for the treatment of metastatic prostate cancer with PARP inhibitors in this subset of patients, especially in the case of BRCA1 or BRCA2 pathogenic/likely pathogenic variants. In face of this new therapeutic opportunity, many issues remain unsolved. This narrative review aims to describe the relationship between homologous recombination repair deficiency and prostate cancer, the techniques used to determine homologous recombination repair status in prostate cancer, the crosstalk between homologous recombination repair and the androgen receptor pathway, the current evidence on PARP inhibitors activity in metastatic prostate cancer also in homologous recombination repair-proficient tumors, as well as emerging mechanisms of resistance to PARP inhibitors. The possibility of combination therapies including a PARP inhibitor is an attractive option, and more robust data are awaited from ongoing phase II and phase III trials outlined in this manuscript.
Assuntos
Inibidores de Poli(ADP-Ribose) Polimerases , Neoplasias da Próstata , Reparo de DNA por Recombinação , Humanos , Masculino , Neoplasias da Próstata/genética , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Proteína BRCA2/genética , Proteína BRCA2/deficiência , Metástase Neoplásica , Proteína BRCA1/genética , Proteína BRCA1/deficiência , Ftalazinas/uso terapêutico , Ftalazinas/farmacologia , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , PiperazinasRESUMO
Histone H2AX plays a key role in DNA damage signalling in the surrounding regions of DNA double-strand breaks (DSBs). In response to DNA damage, H2AX becomes phosphorylated on serine residue 139 (known as γH2AX), resulting in the recruitment of the DNA repair effectors 53BP1 and BRCA1. Here, by studying resistance to poly(ADP-ribose) polymerase (PARP) inhibitors in BRCA1/2-deficient mammary tumours, we identify a function for γH2AX in orchestrating drug-induced replication fork degradation. Mechanistically, γH2AX-driven replication fork degradation is elicited by suppressing CtIP-mediated fork protection. As a result, H2AX loss restores replication fork stability and increases chemoresistance in BRCA1/2-deficient tumour cells without restoring homology-directed DNA repair, as highlighted by the lack of DNA damage-induced RAD51 foci. Furthermore, in the attempt to discover acquired genetic vulnerabilities, we find that ATM but not ATR inhibition overcomes PARP inhibitor (PARPi) resistance in H2AX-deficient tumours by interfering with CtIP-mediated fork protection. In summary, our results demonstrate a role for H2AX in replication fork biology in BRCA-deficient tumours and establish a function of H2AX separable from its classical role in DNA damage signalling and DSB repair.
Assuntos
Proteína BRCA1 , Proteína BRCA2 , Replicação do DNA , Resistencia a Medicamentos Antineoplásicos , Histonas , Inibidores de Poli(ADP-Ribose) Polimerases , Animais , Feminino , Humanos , Camundongos , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteína BRCA1/metabolismo , Proteína BRCA1/deficiência , Proteína BRCA1/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/genética , Proteína BRCA2/deficiência , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Neoplasias da Mama/tratamento farmacológico , Proteínas de Transporte/metabolismo , Proteínas de Transporte/genética , Linhagem Celular Tumoral , Quebras de DNA de Cadeia Dupla , Dano ao DNA , Reparo do DNA , Replicação do DNA/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Histonas/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Rad51 Recombinase/metabolismo , Rad51 Recombinase/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética , Camundongos NusRESUMO
Germ-line mutations in BRCA2 predispose to early-onset cancer. Homozygous mutant mouse, which has Brca2 truncated in exon 11 exhibit paradoxic occurrence of growth retardation and development of thymic lymphomas. However, due to its large embryonic lethality, cohort studies on the thymic lymphomas were not feasible. With the aid of Cre-loxP system, we demonstrate here that thymus-specific disruption of Brca2 allele without crossing it to p53-mutant background leads to the development of thymic lymphomas. Varying from 16 weeks to 66 weeks after birth, 25% of mice disrupted of Brca2 in the thymus died of thymic lymphomas, whereas previous report did not observe lymphomagenesis using similar Cre-loxP system. Future analysis of thymic lymphomas from these mice presented here will provide information on the cooperative mutations that are required for the BRCA2-associated pathogenesis of cancer.