Hou Rui,Sun Xinrui,Cao Shiyao,Wang Yadong,Jiang Luo
The metabolic reprogramming in high-grade serous ovarian carcinoma (HGSOC) affects the tumor stemness, which mediates tumor recurrence and progression. Knowledge of the stemness and metabolic characteristics of HGSOC is insufficient. Squalene epoxidase (SQLE), a key enzyme in cholesterol metabolism, was significantly upregulated in HGSOC samples with a fold change of about 4 in the RNA sequencing analysis. SQLE was positively related to peritoneal metastasis and poor prognosis of HGSOC patients. Functionally, SQLE drove cancer cell proliferation and inhibited apoptosis to accelerate HGSOC growth. SQLE was highly expressed in ALDH + CD133 + FACS-sorted cells derived from HGSOC cells and ovarian cancer stem cells (OCSCs)-enriched tumorspheres. SQLE overexpression resulted in enhanced CSC-like properties, including increased tumorsphere formation and stemness markers expression. In vivo, SQLE not only promoted cell line-derived xenografts growth but extended the OCSCs subpopulation of single-cell suspension. Moreover, non-targeted metabolomics profiling from UPLC-MS/MS system identified 90 differential metabolites responding to SQLE overexpression in HGSOC cells. Among them, the dysfunctional metabolisms of cholesterol and glutathione were involved in the maintenance of HGSOC stemness. Previous studies showed the alteration of N6-Methyladenosine (m6A) modification in HGSOC development. Herein, the m6A modification in the 3’UTR and CDS regions of SQLE mRNA was increased due to upregulated methyltransferases WTAP and downregulated demethylases FTO, which was recognized by m6A-binding proteins IGF2BP3, rather than IGF2BP1 or IGF2BP2, thereby stabilizing the SQLE mRNA. These results suggested that SQLE was a novel potential clinical marker for predicting the HGSOC development and prognosis, as well as a potential therapeutic target of HGSOC.
High-grade serous ovarian cancer (HGSOC) remains the most lethal female cancer by far. Herein, clinical HGSOC samples had higher N 6 -methyladenosine (m 6 A) modification than normal ovarian tissue, and its dysregulation had been reported to drive aberrant transcription and translation programs. However, Kringle containing transmembrane protein 2 (KREMEN2) and its m 6 A modification have not been fully elucidated in HGSOC. In this study, the data from the high-throughput mRNA sequencing (RNA-seq) of clinical samples were processed using the weighted correlation network analysis (WGCNA) and functional enrichment analysis. Results revealed that KREMEN2 was a driver gene in the tumorigenesis of HGSOC and a potential target of m 6 A demethylase fat-mass and obesity-associated protein (FTO). KREMEN2 and FTO levels were upregulated and downregulated, respectively, and correlation analysis showed a significant negative correlation in HGSOC samples. Importantly, upregulated KREMEN2 was remarkably associated with lymph node (LN) metastasis, distant metastasis, peritoneal metastasis, and high FIGO stage (Ⅲ/Ⅳ), independent of the age of patients. KREMEN2 promoted the growth of HGSOC in vitro and in vivo , which was dependent on FTO. The methylated RNA immunoprecipitation-qPCR and RNA immunoprecipitation assays were performed to verify the m 6 A level and sites of KREMEN2. FTO overexpression significantly decreased m 6 A modification in 3'UTR and 5'UTR regions of KREMEN2 mRNA and downregulated its expression. In addition, we found that FTO-mediated m 6 A modification of KREMEN2 mRNA was recognized and stabilized by the m 6 A reader IGF2BP1 rather than IGF2BP2 or IGF2BP3. This study highlights the m 6 A modification of KREMEN2 and extends the importance of RNA epigenetics in HGSOC.
危险品化学品经营许可证（带存储）