Project description:We demonstrate that the catalytic subunit of Polycomb Repressive Complex 2, EZH2, is targeted by the MELK-FOXM1 complex, which in turn promotes resistance to radiation in GSCs. Clinically, EZH2 and MELK are co-expressed in GBM and significantly induced in post-irradiation recurrent tumors whose expression inversely correlated with patient prognosis. Through gain-and loss-of-function study, our data show that MELK or FOXM1 contributes on GSC radioresistance by regulation of EZH2. We used microarrays to validate EZH2 target gene expression. GSCs were treated with shNT (control), shMELK, shFOXM1, and EZH2 overexpression. Total RNA was isolated using the Qiagen RNeasy kit (Qiagen).
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:Asthma is a chronic inflammatory airway disease characterized by airway inflammation and remodeling. The role of 15-oxo-5Z,8Z,11Z,13E-eicosatetraenoic acid (15-oxoETE), a 15-HETE metabolite catalyzed by 15-prostaglandin dehydrogenase (15-PGDH), has been relatively unexplored in asthma. In this study, we used RNA-seq to explore the effect of 15-KETE on the transcriptome of airway epithelial cells, aiming to identify its potential downstream targets and mechanisms of action.
Project description:Glioblastoma progression and recurrence are suggested to be derived by glioblastoma stem-like cells (GSCs). There is limited knowledge about the expression and therapy response of LGR5 in GSCs. We have investigated the role of LGR5 in glioblastoma by knocking down LGR5 using short hairpin RNA targeting LGR5 mRNA (shLGR5) and non-target RNA (shNT) as control.
Project description:In order to investigate the crucial role of PFKFB4 in glioblastoma stem-like cell (GSC) survival, gene expression microarray-based transcriptome analysis was conducted on GSCs transduced for 4 days with PFKFB4 shRNA compared with GSCs transduced with shNT.
Project description:In order to investigate the crucial role of PRKCI in glioblastoma stem-like cell (GSC) survival, gene expression microarray-based transcriptome analysis was conducted on GSCs transduced for 4 days with PRKCI shRNA compared with GSCs transduced with shNT.
Project description:We report that these features are associated with distinct transcriptional programs, with vascular regions showing a proneural profile and hypoxic regions a mesenchymal pattern. As these regions harbor glioma stem cells (GSCs), we investigated the epigenetic regulation of these two niches. Proneural, perivascular GSCs activated EZH2, whereas mesenchymal GSCs in hypoxic regions expressed BMI1 protein. To determine the differential regional activation of EZH2 and BMI1 function, we performed chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) with H3K27me3 (histone modification by EZH2) or H2AK119Ub (histone modification by BMI1) antibodies in CD15-postive GSCs from enhancing and necrotic regions of two GBM specimens, and found over 80% of regional specific target genes displayed distinct H3K27me3 or H2AK119Ub marks, indicating distinct PRC function in GSCs residing in different regions. H3K27me3, generally associated with inhibition of transcription, marked neuronal and cellular development targets in both the enhancing and necrotic regions, albeit without substantial overlap in gene identity, with EZH2/SUZ12/H3K27me3 targets most significantly in the enhancing regions. In contrast, H2AK119Ub marked very different targets in the enhancing and necrotic regions, with H2AK119Ub in CD15-positive GSCs from the hypoxia (necrotic) regions marking genes strongly associated with mesenchymal subtype signaling pathways, such as TGFb, NFkB, and WNT, indicating probable microenvironment-specific functions of EZH2 and BMI1.