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>
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Although most ovarian cancers show prognostically relevant activated T-cell infiltrates, response rates to immune checkpoint inhibitors are very modest4. Memory B-cell and plasma cell infiltrates have been associated with better outcome in ovarian cancer, but the nature and functional relevance of these responses are controversial. Using 3 independent cohorts totaling 575 high-grade serous ovarian cancer (HGSOC) patients, we show that robust humoral responses are heavily dominated by the production of polyclonal IgA, which binds to Polymeric IgA Receptors universally expressed on ovarian cancer cells. Notably, all tertiary lymphoid structures identified in ~21% of HGSOCs contain IgA-producing oligoclonal B-cells. Strikingly, tumor Bcell-derived IgAs effectively target extracellular oncogenic drivers, whereas IgA transcytosis through malignant epithelial cells elicits transcriptional changes that antagonize the RAS pathway and that sensitize tumor cells to T-cell cytolytic killing, hindering malignant progression. Thus, tumor antigen-specific and antigen-independent IgA responses antagonize ovarian cancer growth by governing coordinated tumor cell, T-cell and B-cell responses. These findings provides a platform for the identification of novel targets spontaneously recognized by intratumoral B-cell-derived antibodies, and suggest that immunotherapies that augment B-cell responses may be more effective than T-cell-centric approaches, particularly for malignancies resistant to checkpoint inhibitors.