BACKGROUND Gastric cancer (GC) is one of the most common malignant cancers, with high morbidity and mortality rates worldwide. The present study was to explore whether miR-200b is a tumor suppressor in GC and to unveil the potential mechanisms.METHODS Levels of c-Myc, Cyclin D1, MMP-3 and MMP-9 expression were detected respectively by q-PCR and Western blot assay. BrdU proliferation assay, Cell cycle analysis and Wound-healing were used to study the role of miR-200b with inhibitor, mimics or

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... 1-RNAi in TGF-β1-treated SGC-7901/DDP cells.RESULTS Compared with the paracancerous tissues, miR-200b was decreased in GC patients and SGC-7901/DDP cells. Lower level of miR-200b induced by its inhibitor promoted TGF-β1-treated SGC-7901/DDP cells proliferation and migration, and increased the levels of c-Myc, Cyclin D1, MMP-3, and MMP-9. Interestingly, miR-200b mimics and ZEB1-RNAi were able to reduce the proliferation and migration of TGF-β1-induced SGC-7901/DDP cells as well as their levels of c-Myc, Cyclin D1, MMP-3 and MMP-9. In addition, ZEB1 was indeed the potential target of miR-200b