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:BRMS1L (breast cancer metastasis suppressor 1 likeM-oM-<M-^LBRMS1-like) is a component of the SIN3A-HDAC corepressor complex that suppresses target gene transcription. Here, we show that reduced BRMS1L in breast cancer tissues is associated with tumor metastasis and poor patient survival. Functionally, BRMS1L inhibits migration and invasion of breast cancer cells by inhibiting epithelial-mesenchymal transition (EMT). These effects are mediated by epigenetic silencing of FZD10, a receptor for Wnt signaling, by facilitating the recruitment of HDAC1 to its promoter and enhancing histone H3K9 deacetylation. Consequently, BRMS1L-induced FZD10 silencing inhibits aberrant activation of WNT3-FZD10-M-oM-^AM-"-catenin signaling. Furthermore, BRMS1L is a target of miR-106b and miR-106b upregulation leads to BRMS1L reduction in breast cancer cells. RNAi-mediated silencing of BRMS1L expression promotes metastasis of breast cancer xenografts in immunocompromised mice, while ectopic BRMS1L expression inhibits metastasis. Therefore, BRMS1L provides an epigenetic regulation of Wnt signaling in breast cancer cells and acts as a breast cancer metastasis suppressor. Ther transfection analysis used here were further desxribed in Chang Gong, eta al.2013. miR-106b expression determines the proliferation paradox of TGF-M-NM-2 in breast cancer cells. Oncogene. 2013 A two chip study using total RNA recovered from MDA-MB-231 breast cancer cells transfected with negative control vector or vector overexpressing BRMS1L for 24 hours. Each chip measures the expression 45033 genes were collected from the authoritative data source including NCBI.
Project description:Tumors require ample protein synthesis to grow, and aminoacyl-tRNA synthetases, as critical translation factors, are expected to support cancer progression. Unexpectedly, overexpression of seryl-tRNA synthetase (SerRS) suppresses primary tumor growth of breast cancer. However, the effects of SerRS on metastasis have not been studied. We observe a decrease in SerRS expression in breast cancer patient metastases compared to matched primary tumors, suggesting an inhibitory role of SerRS in metastasis. Through mouse metastasis models using breast cancer cell lines overexpressing SerRS, we show that SerRS impedes both primary tumor growth and establishment of metastases. By inducing SerRS overexpression after primary tumor implantation, we demonstrate the potential of SerRS as an anticancer therapeutic. Through tumor RNA-Seq, we identify Wnt signaling among the top SerRS-regulated pathways. Using cell-based studies, we confirm SerRS suppresses Wnt signaling and metastatic processes in breast cancer cells. To our knowledge, this is the first study to show a translation factor can act as both a tumor and metastasis suppressor.