Project description:EZH2 is frequently over-expressed in aggressive and metastatic solid tumors, including castration resistant prostate cancer (CRPC). We sought to determine EZH2-dependent gene expression programmes in prostate cancer progression, and found an intriguing functional switch of EZH2 from a repressor to an activator during CRPC development. We used microarrays to detail the global profiling of gene expression that are differentially regulated upon EZH2 depletion in two different prostate cancer cell lines. The androgen-dependent prostate cancer cell line LNCaP and the LNCaP-derived androgen-independent cell line LNCaP-abl (abl) were used for this study, as their transcription profiles strongly resemble that of clinical androgen-dependent and castration resistant prostate tumors, respectively. EZH2 was silenced by specific siRNAs in both cell lines, and total RNA was extracted and hybridized on Affymetrix microarrays.
Project description:EZH2 is frequently over-expressed in aggressive and metastatic solid tumors, including castration resistant prostate cancer (CRPC). We sought to determine EZH2-dependent gene expression programmes in prostate cancer progression, and found an intriguing functional switch of EZH2 from a repressor to an activator during CRPC development. We used microarrays to detail the global profiling of gene expression that are differentially regulated upon EZH2 depletion in two different prostate cancer cell lines.
Project description:To determine the altered mRNA expression signatures upon overexpressing EZH2 regulated microRNAs in cancer. To identify EZH2 regulated microRNAs in cancer. Two-condition experiment: Each EZH2 microRNA was overexpressed and compared to a control RNA in BT549 breast cancer cells. In DU145 prostate cancer cell EZH2 was knocked down and comapred to EZH2 scrambled siRNA. Other cell lines were monitored for miRNA expression as they are known to have high endogenous levels of EZH2.
Project description:Prostate cancers are considered immunologically ‘cold’ tumors given the very few patients who respond to checkpoint inhibitor therapy (CPI). Recently, enrichment of interferon stimulated genes (ISGs) predicts a favorable response to CPI across various disease sites. The enhancer of zeste homolog-2 (EZH2) is over-expressed in prostate cancer and is known to negatively regulate ISGs. Here, we demonstrate that a majority of ISGs are not directly silenced by EZH2 mediated H3K27me3 deposition, but instead in a poised chromatin state associated with accessible chromatin (ATAC+) and H3K27ac deposition. Inhibition of EZH2 catalytic activity in prostate cancer models activates a dsRNA-STING-ISG cellular stress response upregulating genes involved in antigen presentation, Th-1 chemokine signaling, and interferon (IFN) response, including PD-L1 that is dependent on STING activation. EZH2 inhibition combined with PD-1 CPI significantly enhances anti-tumor response dependent on up-regulation of tumor PD-L1 expression. Further, combination therapy significantly increases intratumoral trafficking of activated CD8+ T-cells and M1 tumor associated macrophages (TAMs) with concurrent loss of M2 TAMs. Our study identifies EZH2 as a potent inhibitor of antitumor immunity and responsiveness to CPI. This data suggests EZH2 inhibition is a novel therapeutic direction to enhance prostate cancer response to PD-1 CPI.
Project description:Androgen receptor (AR) is a hormone-activated transcription factor that plays important roles in prostate development, function, as well as malignant transformation. The downstream pathways of AR, however, are incompletely understood. AR has been primarily known as a transcriptional activator inducing prostate-specific gene expression. Through integrative analysis of genome-wide AR occupancy and androgen-regulated gene expression, here we report AR as a globally acting transcriptional repressor. This repression is mediated by androgen responsive elements (ARE) and dictated by Polycomb group protein EZH2 and repressive chromatin remodeling. In embryonic stem cells, AR-repressed genes are occupied by EZH2 and harbor bivalent H3K4me3 and H3K27me3 modifications that are characteristic of differentiation regulators, the silencing of which maintains the undifferentiated state. Concordantly, these genes are silenced in castration-resistant prostate cancer rendering a stem cell-like lack of differentiation and tumor progression. Collectively, our data reveal an unexpected role of AR as a transcriptional repressor inhibiting non-prostatic differentiation and, upon excessive signaling, resulting in cancerous de-differentiation. It provides an innovative mechanism for castration resistance and highlights novel therapeutic strategies to treat advanced prostate cancer. Keywords: Genetic Modification compare gene expression in different cell lines with or without androgen treatment or EZH2 knockdown