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:The human A-family DNA polymerase M-NM-8 (Pol q) is a large, multidomain enzyme whose physiological function is still unclear despite its in vitro translesion synthesis capacity in front of DNA damage and its involvement in some features of DNA repair after external stress. Here we present evidence that Pol q holds a novel role in the absence of external stress as a critical determinant of the replication timing program in human cells. Pol q binds to chromatin at early G1 and is required for proper formation of pre-replicative complexe and replication origin activation. Pol q-depleted cells show modified spatial organization of chromatin-loop structures at replication factories. Genome-wide analysis of replication timing shows delayed replication of a part of early replicating domains and advanced replication of a part of late replicating domains following Pol q depletion. Our results identify Pol q as one of the first critical human factors discovered in the replication timing programme. Two-condition experiment, siRNA control vs. siRNA polQ cells. Biological replicates: 2 control replicates, 2 transfected replicates.
Project description:The human A-family DNA polymerase M-NM-8 (Pol q) is a large, multidomain enzyme whose physiological function is still unclear despite its in vitro translesion synthesis capacity in front of DNA damage and its involvement in some features of DNA repair after external stress. Here we present evidence that Pol q holds a novel role in the absence of external stress as a critical determinant of the replication timing program in human cells. Pol q binds to chromatin at early G1 and is required for proper formation of pre-replicative complexe and replication origin activation. Pol q-depleted cells show modified spatial organization of chromatin-loop structures at replication factories. Genome-wide analysis of replication timing shows delayed replication of a part of early replicating domains and advanced replication of a part of late replicating domains following Pol q depletion. Our results identify Pol q as one of the first critical human factors discovered in the replication timing programme. Two-condition experiment, control vs. over expressed polQ cells. Biological replicates: 2 control replicates, 2 transfected replicates.
Project description:The generation of pancreatic organoids from human pluripotent stem cells represents a major breakthrough for regenerative medicine and the modeling of diseases such as diabetes. However, current approaches remain inefficient due to lengthy multi-step differentiation protocols and limited functional maturity in the organoids. In this study, we overcome these challenges using multi-phase optimization screens to achieve rapid generation of functionally mature pancreatic organoids from a stable endocrine progenitor culture. We conducted stepwise culture condition screens that enabled the stable culture of multiple pancreatic progenitor cell states, including the unprecedented stable propagation of NEUROD1-expressing endocrine progenitor-like cells (EpSCs). Further transcriptomic profiling of EpSC confirmed similarity of that to previously reported endocrine progenitor populations. Using EpSCs, we significantly reduced the number of steps and timing required to generate pancreatic organoids, enabling rapid testing of conditions for organoid maturation. Utilizing this optimized protocol, we further tested conditions to promote pancreatic organoid maturation. We identified that exosome-delivered WNT5B, in combination with RSPO1 (exoW/R), could strongly induce non-canonical WNT/JNK signaling, promoting pancreatic organoid maturation. This combinatorial exosome treatment enhances epithelial organization, reduces immature cell states, and significantly improves glucose responsiveness and insulin secretion. Collectively, our work establishes a robust pancreatic differentiation platform that integrates long-term progenitor expansion with optimized organoid maturation. This system provides a reproducible experimental framework for studying pancreatic development, investigating disease mechanisms, and facilitating future translational applications involving pancreatic organoids.
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.