PARP-inhibitors applied to BRCA1-null PDX models
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ABSTRACT:
PROVIDER: PRJEB26804 | ENA |
REPOSITORIES: ENA
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Project description:Metastatic castration-resistant prostate cancer (mCRPC) is a lethal disease characterized by its aggressive nature and resistance to anti-androgen therapies. Although PARP inhibitors (PARPis) have brought new hope for mCRPC patients with homologous recombination (HR) deficient, such as those lacking BRCA1/2, the utility of PARPi monotherapy is significantly restricted, with only 10%-15% of mCRPC patients with BRCA1/2 deficiencies achieving clinical benefit. Thus, there is a critical need for innovative therapeutic strategies for mCRPC patients without BRCA deficiency. In our current study, we elucidate the pivotal role of the ATM-TRMT10A-BRCA1 axis in mediating HR repair and PARPi resistance in mCRPC. We demonstrate that TRMT10A is phosphorylated at S28 by ATM after DNA damage. This phosphorylation is essential for the recruitment of BRCA1 to sites of DNA damage, thereby facilitating HR repair. Deletion of TRMT10A compromises HR repair, rendering tumor cells more sensitive to PARPi. Importantly, we show that TRMT10A expression is upregulated in mCRPC and is modulated by Ubiquitin Specific Peptidase 10 (USP10). Inhibition of USP10 with small molecular inhibitor Spautin-1 leads to TRMT10A degradation and enhances the sensitivity of tumors to PARPi in both cell-derived xenografts (CDX) and patient-derived xenografts (PDX). Our findings underscore the vital role of ATM-TRMT10A-BRCA1 axis in the vulnerability to PARP inhibitors and introduce a promising strategy perspective for exploring synthetic lethality. This approach, which involves the combination of PARP and USP10 inhibitors, could extend therapeutic benefits to a broader group of mCRPC patients without BRCA mutation.
2024-12-30 | PXD059301 |
Project description:BRCA1 deficiencies cause breast, ovarian and other cancers, and render tumours hypersensitive to PARP-inhibitors. To understand resistance mechanisms, we conducted whole-genome CRISPR-Cas9 synthetic-viability/resistance screens in BRCA1-deficient breast cancer cells treated with PARP-inhibitors. Thus, we identified two previously uncharacterized proteins, C20orf196 and FAM35A, whose inactivation confers strong PARP-inhibitor resistance. Mechanistically, we show that C20orf196 and FAM35A form a complex, termed “Shieldin” (SHLD1/2), with FAM35A interacting with single-stranded DNA via its C-terminal OB-fold region. We establish that Shieldin promotes DNA double-strand break (DSB) end-joining, acting as the downstream effector of 53BP1/RIF1/MAD2L2 to restrict DSB resection and counteract homologous recombination in BRCA1-deficient cells by antagonising BRCA2/RAD51 loading. Notably, Shieldin inactivation further sensitises BRCA1-deficient cells to cisplatin, suggesting how defining the SHLD1/2 status of BRCA1-deficient tumours might aid patient stratification and yield new treatment opportunities. Highlighting this potential, we document reduced SHLD1/2 expression in human breast cancers displaying intrinsic or acquired PARP-inhibitor resistance.
2018-05-31 | PXD009830 | Pride
Project description:Despite numerous therapeutic advances over the years, ovarian cancer, especially high grade serous ovarian carcinoma remains the deadliest gynecological malignancy. Although PARP inhibition has been shown to be an effective (maintenance) therapy for homologous recombination repair deficient or BRCA1 mutated ovarian cancer, there may be further potential for combination therapy with other drugs such as immune checkpoint inhibitors. BRCA1 mutation as well as PARP inhibitor (Olaparib) treatment influenced the activation of immune response pathways such as cGAS-STING signaling and Interferon-alpha response in ovarian cancer cell lines. Bioinformatics functional analyses uncovered further immune related cellular responses and signaling pathways such as JAK-STAT signaling.
2023-08-01 | GSE237361 | GEO
Project description:Ovarian high-grade serous carcinoma (HGSC) is the most common and lethal subtype of ovarian cancer with limited therapeutic options. In recent years, PARP inhibitors have demonstrated significant clinical benefits, especially in patients with BRCA1/2 mutations. However, acquired drug resistance and relapse is a major challenge. Therapies disrupting the spliceosome alter cancer transcriptomes and have shown potential to improve PARP inhibitor response. Indisulam (E7070) has been identified as a molecular glue that brings splicing factor RBM39 and DCAF15 E3 ubiquitin ligase in close proximity. Exposure to indisulam induces RBM39 proteasomal degradation through DCAF15-mediated polyubiquitination and subsequent RNA splicing defects. In this study, we demonstrate that loss of RBM39 induces splicing errors in DNA damage repair genes in ovarian cancer, leading to increased sensitivity to PARP inhibitors such as olaparib. Indisulam synergized with olaparib in multiple in vitro models of ovarian cancer regardless of PARP inhibitor sensitivity and improved olaparib response in mice bearing PARP inhibitor-resistant tumors. DCAF15 expression, but not BRCA1/2 mutational status, was essential for the synergy between indisulam and olaparib, suggesting that the combination therapy may benefit patients irrespective of their BRCA1/2 status. These findings demonstrate that combining RBM39 degraders and PARP inhibitors is a promising therapeutic approach to improving PARP inhibitor response in ovarian HGSC
2023-01-22 | GSE223011 | GEO
Project description:Immune checkpoint inhibitors (ICIs) have revolutionized treatment for several tumor indications without demonstrated benefit for ovarian cancer patients. To improve the therapeutic ratio of ICIs in ovarian cancer patients, several different clinical trials are testing combinations with poly (ADP-ribose) polymerase (PARP) inhibitors. Comparing the immunomodulatory effects of clinically advanced PARP inhibitors may help to identify the best partner to combine with ICIs. We examined the treatment effect of talazoparib (a PARP trapper) and veliparib (a solely PARP enzymatic inhibitor) in homologous recombination deficient (HRD) and homologous recombination proficient (HRP) high-grade serous tubo-ovarian carcinoma (HGSC) cell lines on immune-related gene expression. We discovered and validated that CXCL8, IL-6, and TNF gene expression were upregulated after talazoparib treatment in both OVCAR3 (HRD) and CAOV3 (HRP) HGSC cell lines. In contrast, veliparib treatment slightly elevated similar genes exclusively in a HRD HGSC cell line model. We expanded these studies to include olaparib, a PARP trapper less potent than talazoparib, and found effects specific to COV361 (BRCA1 mutant) and OVCAR8 (BRCA1 methylated) HGSC cells but not all HRD HGSC cell lines. Our studies also identified differences among PARP trappers versus veliparib on augmenting CXCL10 expression. Finally, we show that talazoparib modulates the CXCL10 response in cGAS-defective cell lines, independent of the cGAS-STING pathway. These mechanistic studies advance our understanding of how different PARP inhibitors affect the immune system in various genetic backgrounds.
2025-01-03 | GSE285827 | GEO
Project description:The poly (ADP-ribose) polymerases (PARPs) inhibitors are an exciting new class of agents that have shown efficacy in treating various cancers, especially these harboring BRCA1/2 mutations. The cancer associated BRCA1/2 mutations disrupt DNA double strand break (DSB) repair by homologous recombination (HR). PARP inhibitors (PARPi) have been applied to trigger synthetic lethality in BRCA1/2-mutated cancer cells by promoting accumulation of toxic DSBs. Unfortunately, PARP inhibitor (PARPi) resistance is common and develops through multiple mechanisms. Restoration of HR and/or stabilizing replication forks are two major mechanisms of PARPi resistance in BRCA1/2-mutated cells. To further understand the mechanisms of drug resistance to PARPi, we undertook an unbiased approach with a CRISPR-pooled library to screen new genes whose loss-of-function confers resistance to PARPi olaparib. We identified ZNF251, a transcription factor, and confirmed its loss-of-function led to the PARPi resistance in BRCA1-mutated breast and ovarian cancer lines. Elevated activities of both HR and non-homologous end joining (NHEJ) repair were detected in cancer cells harboring BRCA1 mutation and ZNF251 deletion (BRCA1mut+ZNF251del) and were associated with enhanced expression of RAD51 and Ku70/Ku80, respectively. Furthermore, we showed that DNA-PKcs inhibitor restored sensitivity of BRCA1mut+ZNF251del cells to PARPi. Taken together, our study identified a novel gene whose loss of function conferred resistance to PARPi, providing new insight into signaling pathways that contribute to acquired resistance in BRCA1-mutated breast and ovarian cancers.
2023-05-31 | GSE205221 | GEO
Project description:To examine the immune responses that occur in Brca1-deficent tumors upon olaparib treatment, we performed gene expression analysis of a panel of 4604 cancer and immune-related genes in tumor tissues harvested from Brca1-deficient ovarian tumor-bearing mice after treatment with olaparib or vehicle. Transcriptome analysis showed that the expression of genes associated with immune response, T-cell activation and interferon-gamma(IFNgamma) response were markedly upregulated in tumors treated with olaparib as compared to vehicle. Our data reveal the antitumor immune response of PARP inhibition and demonstrate that it contributes to therapeutic efficacy of PARP inhibition in Brca1-deficient tumors.
2019-02-13 | GSE120500 | GEO
Project description:Although PARP inhibitors (PARPi) now form part of the standard-of-care for the treatment of homologous recombination defective cancers, de novo and acquired resistance limits their overall effectiveness. Previously, overexpression of the BRCA1-∆11q splice variant has been shown to cause PARPi resistance. How cancer cells achieve increased BRCA1-∆11q expression has remained unclear. Using isogenic cells with different BRCA1 mutations, we show that reduction in HUWE1 leads to increased levels of BRCA1-∆11q and PARPi resistance. This effect is specific to cells able to express BRCA1-∆11q (e.g. BRCA1 exon 11 mutant cells) and is not seen in BRCA1 mutants that cannot express BRCA1-∆11q, nor in BRCA2 mutant cells. As well as increasing levels of BRCA1-∆11q protein in exon 11 mutant cells, HUWE1 silencing also restores RAD51 nuclear foci and platinum salt resistance. HUWE1 catalytic domain mutations were also seen in a case of PARPi resistant, BRCA1 exon 11 mutant, high grade serous ovarian cancer. These results suggest how elevated levels of BRCA1-∆11q and PARPi resistance can be achieved, identify HUWE1 as a candidate biomarker of PARPi resistance for assessment in future clinical trials and illustrate how some PARPi resistance mechanisms may only operate in patients with particular BRCA1 mutations.
2023-07-18 | PXD040430 | Pride
Project description:To detect the off-target effects of PARP inhibition, a quantitative mass spectrometry-based proteomic analysis was conducted of a BRCA1-mutated HGSOC cell line treated with low doses of two PARPi, Niraparib and Rucaparib.
2022-04-15 | PXD027177 | Pride