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:Bone is the most common metastasis site in patients with breast cancer, and approximately up to 80% of patients with advanced breast cancer (BC) develop bone metastasis (BM), which leads to a worse prognosis with a median survival of 16 months and skeletal-related events (SREs), including severe bone pain, pathological fracture, hypercalcemia and lethal complications. Using quantitative proteomics mass-spectrometry (MS) analysis of low bone-metastatic BC cells (MDA-MB-231) and high bone-metastatic BC cells (SCP2), we identified an unreported breast cancer (BC) cells–secreted microprotein, LINC00263-P, encoded by lincRNA LINC00263 and clinically associated with BC bone-tropism.
Project description:This project aims to identify and quantify TPM3P9 RNA-associated proteins in primary breast cancer cells (PBCs#2/#3/#5) and bone-metastatic breast cancer cells (BMBCs#2/#3/#5) using 4D-DIA LC–MS/MS. RNA pulldown assays were performed with tRSA-based TPM3P9 RNA to capture interacting proteins, which were subsequently analyzed by 4D-DIA-based quantitative proteomics. The objective is to elucidate the translational regulation mechanism of osteolysin in bone-metastatic breast cancer cells and to identify specific RNA-binding proteins involved in osteolysin translation.
Project description:1,322 morphologically unidentified fragmentary bone specimens were analyzed using MALDI-TOF and a subset of 341 bone specimens with LC-MS/MS in order to characterize their proteome for species identification and potential hominin specimens related to the LRJ transitional period derived from the site Ilsenhöhle Ranis, Germany (50°39.7563’N, 11°33.9139’E).
