J Cancer 2019; 10(18):4368-4379. doi:10.7150/jca.25422 This issue
1. Institute of Precision Medicine, The Xiangya Hospital, State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan 410078, China
2. NHC Key Laboratory of Cancer Proteomics & Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
3. Department of Gastroenterology, The Xiangya Hospital, Central South University, Changsha 410008, China
S-Adenosylmethionine (SAMe) is a kind of common liver-protection medicine. Recent studies have shown that SAMe has the inhibitory effects on hepatocellular carcinoma (HCC). But the specific mechanism has not been elucidated. Here, we examine the effects and relevant mechanisms of SAMe on human hepatocellular carcinoma cell HepG2 and mouse hepatocyte AML12. We applied the technique of RNA sequencing (RNA-Seq) to identify the differentially expressed genes between HepG2 cells which were treated with SAMe or not. And western blot and Quantitative RT-PCR was used to confirm some of these genes. To investigate the response to SAMe treatment, cell proliferation assay (MTS) and flow cytometry-based assays were carried out. A total of 472 SAMe-related genes were identified by RNA-Seq. We found that differentially expressed genes were enriched in cell cycle related signaling pathway significantly by the KEGG and GO Pathway enrichment analysis. Through the construction of protein-protein interaction network, we observed the module associated with cell cycle is in the core of the whole network. All these results implied that cell cycle pathway may be very important in the regulation of SAMe effected on HepG2 cells. Then the RNA-Seq-characterized genes involved in cell cycle (MCM3, MCM4, and E2F1) were confirmed by Western blot and Quantitative RT-PCR in HepG2 and AML12 cells. MTS analysis showed that SAMe could diminish cell proliferation. And flow cytometry-based assays indicated that treatment with SAMe altered cell cycle kinetic S phase cell cycle arrest. Altogether, our data uncovered the evidence of the antiproliferative action of SAMe in liver cells, and SAMe could lead to cell cycle inhibition by up-regulating MCM3, MCM4 and E2F1 expression. It provided an important theoretical basis for the clinical chemoprevention and treatment in HCC of SAMe.
Keywords: S-Adenosylmethionine, Liver cell, Cell cycle, Proliferation