Project description:ARID1A, a subunit of SWI/SNF chromatin remodeling complex. SWI/SNF complex can regulate expression of genes involved in vital biological processes such as cell cycle, DNA damage repair and development. ARID1A is known to have high mutation rate in human cancers including bladder cancer, leading to its loss of function. Publicly available whole exome sequencing data for muscle invasive and non-muscle invasive bladder cancers, show fraction of tumors with truncated ARID1A. Thus identifying therapeutic strategies for ARID1A mutant cancers is of high importance. EZH2, a histone methyltransferase is known to over-express and play pivotal role in aggressive bladder cancer. Our preliminary studies show that treatment of EZH2 inhibitor (GSK126) on ARID1A mutant bladder cancer cells significantly reduced cancer cell viability, invasion and colony formation relative to wild type ARID1A containing cells. Here, we performed microarray experiments to assess the effect of EZH2 inhibitor on global transcriptome of both ARID1A mutant and wild type bladder cancer cell line.
Project description:Metastatic urothelial carcinoma of the bladder is generally incurable with current systemic therapies. Chromatin modifiers are frequently mutated in bladder cancer, with ARID1A inactivating mutations present in 20% of tumors. EZH2 is a histone methyltransferase that acts as an oncogene that functionally opposes ARID1A. In addition, PI3K signaling is activated in over 20% of bladder cancers. Here we show that ARID1A-mutant tumors are more sensitive to EZH2 inhibition than ARID1A-wild-type tumors. Mechanistic studies reveal that: 1) ARID1A deficiency results in a dependency on PI3K/AKT/mTOR signaling via upregulation of a non-canonical PI3K regulatory subunit PIK3R3, and: 2) EZH2 inhibitor sensitivity is due to upregulation of PIK3IP1, an inhibitor protein of PI3K signaling. Thus, our studies suggest that a subset of bladder cancers with ARID1A mutations can be treated with inhibitors of EZH2 and/or PI3K, and reveal novel mechanistic insights into the role of non-canonical PI3K constituents in bladder cancer biology.
Project description:ARID1A-mutant bladder cancer is dependent on PI3K signaling and is sensitive to EZH2 and/or PI3K inhibition. Clinical trials in molecularly selected patients should be considered.
Project description:ARID1A, an epigentic modifier, is often mutated in ovarian clear cell carcinoma (OCCC). In addition, EZH2 is frequently upregulated in OCCC. Inhibtion of EZH2 with an inhibitor (GSK126) selectively inhibits ARID1A-mutated cells. This study was designed to understand changes in gene expression profiles following EZH2 inhibition or ARID1A restoration. Chromatin remodelers such as ARID1A are frequently mutated in a broad array of cancers. However, targeted cancer therapy based on ARID1A mutation status has not been described. Intriguingly, ARID1A mutated cancers typically lack genomic instability, suggesting significant involvement of epigenetic mechanisms. Here we show that inhibition of the EZH2 methyltransferase acts in a synthetic lethal manner in ARID1A mutated cells. Remarkably, ARID1A mutation status correlated with response to EZH2 inhibitor. Genome-wide profiling revealed antagonistic roles of ARID1A and EZH2 in gene regulation. Further, we identified PIK3IP1 as a direct ARID1A/EZH2 target gene whose upregulation contributes to the observed synthetic lethality in the EZH2 inhibitor treated ARID1A mutated cells. Significantly, EZH2 inhibitor caused the regression of established ARID1A mutated tumors in vivo. Together, this data demonstrate a synthetic lethality between ARID1A mutation and EZH2 inhibition. They indicate that pharmacological inhibition of EZH2 represents a novel treatment strategy for ARID1A mutated cancers.
Project description:Advanced bladder cancer remains a difficult cancer to treat, and for the majority of patients, current standard treatments ultimately prove ineffective. These tumors frequently harbor mutations in the BAF complex subunit ARID1A, which has been reported to confer sensitivity to EZH2 inhibition in several tumor types. Here we describe the generation of CPI-0209, a best-in-class, orally available EZH2 inhibitor. We show that mutant bladder cancer lines harboring ARID1A loss of function (LOF) mutations are preferentially sensitive to inhibition of EZH2. Treatment with CPI-0209 not only elicits a significant monotherapeutic response in ARID1A mutant models, it also outperforms cisplatin and improves response in chemo-resistant models. These findings shine light on new therapeutic opportunities for patients with advanced urothelial carcinoma.
Project description:Advanced bladder cancer remains a difficult cancer to treat, and for the majority of patients, current standard treatments ultimately prove ineffective. These tumors frequently harbor mutations in the BAF complex subunit ARID1A, which has been reported to confer sensitivity to EZH2 inhibition in several tumor types. Here we describe the generation of CPI-0209, a best-in-class, orally available EZH2 inhibitor. We show that mutant bladder cancer lines harboring ARID1A loss of function (LOF) mutations are preferentially sensitive to inhibition of EZH2. Treatment with CPI-0209 not only elicits a significant monotherapeutic response in ARID1A mutant models, it also outperforms cisplatin and improves response in chemo-resistant models. These findings shine light on new therapeutic opportunities for patients with advanced urothelial carcinoma.
Project description:Advanced bladder cancer remains a difficult cancer to treat, and for the majority of patients, current standard treatments ultimately prove ineffective. These tumors frequently harbor mutations in the BAF complex subunit ARID1A, which has been reported to confer sensitivity to EZH2 inhibition in several tumor types. Here we describe the generation of CPI-0209, a best-in-class, orally available EZH2 inhibitor. We show that mutant bladder cancer lines harboring ARID1A loss of function (LOF) mutations are preferentially sensitive to inhibition of EZH2. Treatment with CPI-0209 not only elicits a significant monotherapeutic response in ARID1A mutant models, it also outperforms cisplatin and improves response in chemo-resistant models. These findings shine light on new therapeutic opportunities for patients with advanced urothelial carcinoma.
Project description:Germ cell tumors (GCTs) are the most common solid malignancies in young men. Although high cure rates can be achieved at early stages, metastases, resistance to cisplatin-based therapy, and late toxicities still represent a lethal threat, arguing for the need of new therapeutic options. In a previous study, we identified downregulation of the chromatin-remodeling SWI/SNF complex member ARID1A as a key event in the mode of action of the histone deacetylase inhibitor romidepsin, subsequently leading to induction of stress, apoptosis and cell cycle regulators. Additionally, ARID1A is mutated in many different tumor types, like bladder, breast or ovarial cancer. There, the loss-of-function mutations re-sensitize these tumor types to various drugs, like EZH2-, PARP-, HDAC-, HSP90- or ATR-inhibitors. Thus, ARID1A presents as a promising target for synthetic lethality and combination therapy. In this study, we deciphered the molecular function of ARID1A and screened for the potential of two pharmacological ARID1A inhibitors as a new therapeutic strategy to treat GCTs. By CRISPR/Cas9, we generated ARID1A-deficient GCT cells and demonstrate that ARID1A regulates transcription, DNA repair and the epigenetic landscape on DNA and histone level via DNA Polymerase POLE and the DNA methyltransferase 1-associated protein DMAP1. Additionally, ARID1A deficiency or pharmacological inhibition considerably sensitized (cisplatin-resistant) GCT cells towards ATR inhibition. Thus, ARID1A might be new combination partner for ATR inhibitors in the treatment of GCTs.
Project description:Advanced bladder cancer remains a difficult cancer to treat, and for the majority of patients, current standard treatments ultimately prove ineffective. These tumors frequently harbor mutations in the BAF complex subunit ARID1A, which has been reported to confer sensitivity to EZH2 inhibition in several tumor types. Here we describe the generation of CPI-0209, a best-in-class, orally available EZH2 inhibitor. We show that mutant bladder cancer lines harboring ARID1A loss of function (LOF) mutations are preferentially sensitive to inhibition of EZH2. Treatment with CPI-0209 not only elicits a significant monotherapeutic response in ARID1A mutant models, it also outperforms cisplatin and improves response in chemo-resistant models. These findings shine light on new therapeutic opportunities for patients with advanced urothelial carcinoma.
Project description:ARID1A, an epigentic modifier, is often mutated in ovarian clear cell carcinoma (OCCC). In addition, EZH2 is frequently upregulated in OCCC. Inhibtion of EZH2 with an inhibitor (GSK126) selectively inhibits ARID1A-mutated cells. This study was designed to understand changes in gene expression profiles following EZH2 inhibition or ARID1A restoration.