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The aim of this study is to   investigate the effect of miRNA-92a on GC cell proliferation, migration and invasiveness, and the mechanism(s) involved.  Four GC cell lines (SGC-7901, BGC-823, MKN45 and HGC-27) and normal human gastric epithelial cells (GES1) were used in this study. MicroRNA-92a mimics or inhibitor were transfected into the cells. The results of transfection were assessed using real-time quantitative polymerase chain reaction (qRT-PCR). Cell proliferation, migration, invasiveness and apoptosis were determined using cell counting kit 8 (CCK-8), scratch test, Transwell invasion assay, and flow cytometric analysis, respectively. The protein target of miRNA-92a was predicted using Bioinformatics. The expression of FOXO1 protein was measured using Western blotting. The expression of miRNA-92a was significantly upregulated in GC cells, relative to normal gastric epithelial cells (p < 0.05). Overexpression of miRNA-92a significantly promoted the proliferation, migration and invasiveness of GC cells, but significantly inhibited their apoptosis (p < 0.05). MicroRNA-92a directly targeted FOXO1 gene, and significantly reduced its protein expression. Overexpression of miRNA-92a promotes the proliferation, migration and invasiveness of GC cells, and plays a role similar to that of oncogene. It directly targets FOXO1 gene by inhibiting its protein expression.

Background: Cell division cycle associated protein-3 (CDCA3) has been reported frequently upregulated in various cancers. It has been progressively realized that changed DNA methylations occur in diverse carcinomas. However, the concrete involvement of CDCA3 and DNA methylation in gastric cancer (GC) still needs to be further elucidated., Methods: In this study, quantitative reverse-transcription polymerase chain reaction (PCR) was utilized to determine the relative expressions of CDCA3 in GC and normal tissue samples. The methylation condition of CDCA3 was determined by bisulfite-sequencing PCR (BSP) and methylation-specific PCR (MSP). A chromatin immunoprecipitation (ChIP) assay and luciferase activity assay was used for the interaction between transcription factors and promoters and binding site determination, respectively. The effects of knockdown or overexpression of specificity protein 1 (SP1) or CDCA3 on GC cells in vitro were further assessed via wound healing assay, colony formation assay, and matrigel invasion assay., Results: In comparison to paired normal tissues, CDCA3 expressions were significantly increased in the GC tissues. The CDCA3 expression was regulated by DNA methylation, with the CpG island hypomethylation responsible for CDCA3 upregulation of GC. ChIP assays verified that the activity of SP1 binding to the CDCA3 promoter was dramatically increased. When the CDCA3 expression was downregulated in MKN45 cells by knockdown SP1, the proliferation ability, healing ability, and invasive ability were significantly suppressed., Conclusion: The process by which SP1 bound to the nearest promoter region was expedited in GC cells, by which DNA was hypomethylated and CDCA3 expression was promoted. The effect on cell proliferation and invasion by CDCA3 was under the regulation of SP1 and also affected by hypomethylation of DNA., (© 2019 Wiley Periodicals, Inc.)

Nectin-4, a member of the Nectin family that includes 4 Ca + -independent immunoglobulin-like cell adhesion molecules, plays a carcinogenic role in multiple cancers. However, Nectin-4 expression and its biological role in gastric cancer (GC) remain largely unknown. In this study, quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry were used to evaluate the expression patterns of Nectin-4 in GC specimens and cell lines. We observed that high expression of Nectin-4 in GC patients was associated with TNM stage and lymph node metastasis status, and poor prognosis. In addition, cell proliferation and cell migration assays in vitro and tumorigenicity in vivo were performed to observe the effects of up-regulation and down-regulation of Nectin-4 expression on GC cell phenotypes. In further studies, the PI3K/AKT signaling pathway was revealed to be involved in Nectin-4-mediated GC progression. These results demonstrated that Nectin-4 had a promoter effect on human GC cell growth and motility, indicating that Nectin-4 may serve as an effective therapeutic target in GC., (Copyright © 2017. Published by Elsevier Inc.)