Mir-935 to suppress gastric signet ring cell carcinoma tumorigenesis by targeting Notch1 expression.

Abstract

77 Background: Although the comprehensive treatment has improved outcomes in most advanced gastric cancers, these protocols have had little effect on advanced gastric signet-ring cell carcinoma (GSRCC). New biomarkers and therapeutic targets are needed to improve its outcomes. MicroRNAs have been closely linked to the carcinogenesis of gastric cancer and have been considered as powerful prognostic markers. The function of miR-935 has never been reported in cancer before. Methods: We used microarrays in six cell lines to explore which miRNAs had dysregulated expression in GSRCC, includingGES-1, SGC-7901, MGC8-03, AGS,MKN-45 and KATO-III. We selected MKN-45 and KATO-III (with down-regulated miR-935) to transfect the miR-935 mimic, and MGC8-03 and HGC-27 (with up-regulated miR-935) to transfect the miR-935 inhibitor. TargetScan 7.0 predicted that Notch1 would have a single conserved binding sequence for miR-935 in the 3′UTR. We also assessed miR-935 expression in clinical gastric carcinoma tissue samples with adjacent normal tissue samples from the same patient. Data were analyzed with SPSS v.17.0 software. Results: Over-expression of miR-935 markedly decreased proliferation, migration and invasion of MKN-45 and KATO-III cells compared with the negative control. In contrast, the inhibitor that was transfected into MGC8-03 and HGC-27 cells significantly increased proliferation, migration and invasion compared the negative control. These results indicate that ectopic miR-935 expression decreases GSRCC proliferation, migration and invasion in vitro, and acted as a tumor suppressor for GSRCC. Expression of Notch1 is negatively regulated by miR-935. Notch1 knock-down significantly inhibited GSRCC proliferation, migration and invasion. MiR-935 was downregulated in GSRCC tissues. Conclusions: The expression of miR-935 in GSRCC cell lines is lower than in non-GSRCC cell lines, and enhanced expression of miR-935 in GSRCC cell-lines inhibit cell proliferation, migration and invasion. Notch1 is a direct target of miR-935 to reduce the proliferation, migration/invasion of GSRCC cells. MiR-935 is a potential marker for GSRCC diagnosis and therapy.