ATF6-Mediated Signaling Contributes to PARP Inhibitor Resistance in Ovarian Cancer
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE190902 | GEO | 2021/12/21
REPOSITORIES: GEO
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Project description:Chemical modifications of RNAs have emerged as a new layer of epigenetic gene regulation. N6-methyladenosine (m6A) is the most abundant chemical modification of messenger RNA (mRNA). The m6A modification affects RNA fate and functions such as RNA stability. Despite the high initial response rates to PARP inhibitors in BRCA1/2-mutated epithelial ovarian cancers (EOC), PARP inhibitor (PARPi) resistance remains a major challenge. The role of m6A modification in PARPi resistance has not previously been explored. Here we show that m6A modification of FZD10 mRNA contributes to PARPi resistance by upregulating the Wnt/-catenin pathway in BRCA-mutated EOC cells. Global m6A profile reveals a significant increase in m6A modification in FZD10 mRNA. This correlates with an increase in FZD10 mRNA stability and an upregulation of the Wnt/-catenin pathway in PARPi resistant cells. FZD10 knockdown or inhibition of the Wnt/-catenin sensitizes the resistant cells to PARPi. Mechanistically, downregulation of m6A demethylases FTO and ALKBH5 is sufficient to increase FZD10 mRNA m6A modification and reduce PARPi sensitivity, which correlates with an increase in homologous recombination activity. Moreover, PAPRi and Wnt/-catenin inhibitor showed synergistic suppression of growth of PAPRi resistant cells both in vitro and in vivo in a xenograft ovarian cancer mouse model. Our results show that m6A contributes to PAPRi resistance in BRCA-deficient EOC cells by upregulating the Wnt/-catenin pathway through stabilizing FZD10. They also suggest that inhibition of Wnt/-catenin pathway represents a potential strategy to overcome PARPi resistance.
2019-09-14 | GSE119963 | GEO
Project description:Background: PARP inhibitors (PARPi) kill cancer cells by stalling DNA replication and preventing DNA repair, resulting in a critical accumulation of DNA damage. Resistance to PARPi is a growing clinical problem in the treatment of high grade serous ovarian carcinoma (HGSOC). Acetylation of histone H3 lysine 14 (H3K14ac) and associated histone acetyltransferases (HATs) have known functions in DNA repair and replication, but their expression and activities have not been examined in the context of PARPi-resistant HGSOC. Results: Using mass spectrometry profiling of histone modifications, we observed altered H3K14ac enrichment in PARPi-resistant HGSOC cells relative to isogenic PARPi-sensitive lines. By RT-qPCR and RNA-Seq, we also observed altered expression of numerous HATs in PARPi-resistant HGSOC cells and a PARPi-resistant PDX model. Knockdown of HATs only modestly altered PARPi response, although knockdown and inhibition of PCAF significantly increased resistance. Pharmacologic inhibition of HBO1 severely depleted H3K14ac but did not affect PARPi response. However, knockdown and inhibition of BRPF3, which is known to interact in a complex with HBO1, did reduce PARPi resistance. Conclusions: This study demonstrates that severe depletion of H3K14ac does not affect PARPi response in HGSOC. Our data suggest that bromodomain functions of HAT proteins such as PCAF, or accessory proteins such as BRPF3, may play a greater role in PARPi response than acetyltransferase functions.
2021-12-22 | GSE191231 | GEO
Project description:Mutations in isocitrate dehydrogenase (IDH) genes render affected gliomas sensitive to PARP inhibition due to epigenetic reprogramming of the DNA damage repair circuits. However, PARPi treated tumor eventually relapse. We report in this study that anti-angiogenetic agent lenvatinib efficiently cooperate with PARPi and the combination therapy induces marked tumor regression and significant extension of survival time. Genomic study with PARPi and lenvatinib treated tumor samples uncovered that PARPi evokes global transcriptome changes that are overall pro-inflammatory, thus inducing tumor angiogenesis. We identified that prickle planar cell polarity protein 4 (Prickle4) as the specific mediator for PARPi induced neovascularization. Suppression of Prickle4 efficiently overcomes PARPi resistance in these tumors. Overall, multimodality therapy combining PARPi and anti-angiogenetic agents represents a feasible treatment that is of excellent potential for clinical applications.
2024-05-01 | GSE249818 | GEO
Project description:ATF6-Mediated Signaling Contributes to PARP Inhibitor Resistance in Ovarian Cancer
| PRJNA788907 | ENA
Project description:The majority of patients with late-stage breast cancer develop distal bone metastases. The bone microenvironment can affect response to therapy, and uncovering the underlying mechanisms could help identify improved strategies for treating bone metastatic breast cancer. Here, we observed that osteoclasts reduced the sensitivity of breast cancer cells to DNA damaging agents, including cisplatin and the PARP inhibitor (PARPi) olaparib. Metabolic profiling identified elevated glutamine production by osteoclasts. Glutamine supplementation enhanced the survival of breast cancer cells treated with DNA damaging agents, while blocking glutamine uptake increased sensitivity and suppressed bone metastasis. GPX4, the critical enzyme responsible for glutathione oxidation, was upregulated in cancer cells following PARPi treatment through stress-induced ATF4-dependent transcriptional programming. Increased glutamine uptake and GPX4 upregulation concertedly enhanced glutathione metabolism in cancer cells to help neutralize oxidative stress and generate PARPi resistance. Analysis of paired patient samples of primary breast tumors and bone metastases revealed significant induction of GPX4 in bone metastases. Combination therapy utilizing PARPi and zoledronate, which blocks osteoclast activity and thereby reduces the microenvironmental glutamine supply, generated a synergistic effect in reducing bone metastasis. These results identify a role for glutamine production by bone-resident cells in supporting metastatic cancer cells to overcome oxidative stress and develop resistance to DNA-damaging therapies.
2023-11-12 | GSE208234 | GEO
Project description:Although Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) have been approved in multiple diseases, including BRCA1/2 mutant breast cancer, responses are usually transient thus requiring the development of combination therapies that can capitalize on PARPi activity. We thus explored mechanisms underlying sensitivity and resistance to PARPi using two intrinsically sensitive and resistant syngeneic murine breast cancer models. Our data indicate that the PARPi sensitive tumor model has a high ratio of M1 anti-tumor/M2 pro-tumor macrophages with the M1/M2 ratio being increased by PARPi. In contrast the PARPi resistant tumor model had very low levels of M1 macrophages and thus a low M1/M2 ratio that was not altered by PARPi. Our data indicate that co-transplantation of the PARPi sensitive and the PARPi resistant tumor results in accumulation of M2 macrophages in the sensitive tumor, rendering the sensitive tumor PARPi resistant. C5aR1 and RPS19/C5aR1 signaling is selectively elevated in the M2 macrophages that are associated with PARPi resistance. Strikingly C5aR1 targeting decreased M2 macrophages, while sparing M1 macrophages rendering PARPi resistant tumors sensitive to PARPi. Consistent with the murine data, human breast cancers with high C5aR1 levels have a poor response to immune checkpoint blockade. Thus targeting C5aR1 may represent a therapeutic approach to selectively deplete M2 macropahges and engender sensitivity to PARPi and potentially other therapeutic approaches.
2023-06-30 | GSE215908 | 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: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:The synthetic lethal association between BRCA deficiency and poly (ADP-ribose) polymerase (PARP) inhibition supports PARP inhibitor (PARPi) clinical efficacy in BRCA-mutated tumors. PARPis also demonstrate activity in non-BRCA mutated tumors presumably through induction of PARP1-DNA trapping. Despite pronounced clinical response, therapeutic resistance to PARPis inevitably develops. An abundance of knowledge has been built around resistance mechanisms in BRCA-mutated tumors, however, parallel understanding in non-BRCA mutated settings remains insufficient. In this study, we find a strong correlation between the epithelial-mesenchymal transition (EMT) signature and resistance to a clinical PARPi, Talazoparib, in non-BRCA mutated tumor cells. Genetic profiling demonstrates that SNAI2, a master EMT transcription factor, is transcriptionally induced by Talazoparib treatment or PARP1 depletion and this induction is partially responsible for the emerging resistance. Mechanistically, we find that the PARP1 protein directly binds to SNAI2 gene promoter and suppresses its transcription. Talazoparib treatment or PARP1 depletion lifts PARP1-mediated suppression and increases chromatin accessibility around SNAI2 promoters, thus driving SNAI2 transcription and drug resistance. We also find that depletion of the chromatin remodeler CHD1L suppresses SNAI2 expression and reverts acquired resistance to Talazoparib. The PARP1/CHD1L/SNAI2 transcription axis might be therapeutically targeted to re-sensitize Talazoparib in non-BRCA mutated tumors.
2022-07-08 | PXD033530 | Pride
Project description: Not available
| S-EPMC6946874 | biostudies-literature