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:<p>BRCA1 mutations are a hallmark of hereditary ovarian cancer, strongly linked to deficiencies in homologous recombination (HR) DNA repair and impaired DNA replication fork protection. However, its roles in cancer progression beyond maintaining genomic integrity remain poorly understood. Through metabolomics approaches, we found BRCA1-deficiency strikingly increased choline metabolism. Loss of BRCA1 promotes choline uptake through upregulating choline transporter-like protein 4 (CTL4). BRCA1 directly binds and recruits EZH2-mediated H3K27Me3 deposition to CTL4 promoter. CTL4 was therefore overexpressed in ovarian cancer tissues with BRCA1 mutations. Furthermore, BRCA1-deficiency significantly promotes ovarian cancer invasion, while inhibition of CTL4 reverses the high metastatic potential of BRCA1-deficient ovarian cancer cells, suggesting the functionality and specificity of CTL4 as a therapeutic target. Additionally, we discovered that phosphocholine, the choline metabolite increased by CTL4 overexpression, interacted with and stabilized the epithelial-to-mesenchymal transition inducer FAM3C in BRCA1-deficient ovarian cancer cells. Importantly, we identified a potent CTL4 inhibitor, DT-13, which significantly reduces choline metabolism and effectively suppresses metastasis in BRCA1-deficient ovarian cancers. Therefore, our study uncovers a mechanism underlying metastasis in BRCA1-deficient cancers and identifies CTL4 as a therapeutic target for metastatic ovarian cancer patients with BRCA1 mutations.</p>