Microrna-29b Regulates Osteopontin Dependent Proliferation Function And Cell Cycle In Esophageal Cancer Lines

Bioinformatics analysis showed that osteopontin could be important target genes of miR-29b. The expression of miR-29b was down regulated in esophageal cancer tissues and esophageal cancer cell lines compared to the normal tissues and normal esophageal cell line respectively. MTT assay, colony formation assay and cell cycle analysis were performed to assess the effect of miR-29b on biological behavior of esophageal cancer cells. The gain-of-function studies that raised miR-29b expression showed reductions in cell proliferation, arrest of cell cycle in G0/G1 phase. Silencing target gene expression was used to investigate whether the effect of downregulation of target protein has the similar effect as miR-29b overexpression in esophageal cancer cell. Furthermore, the dual-luciferase reporter assay demonstrated that miR-29b inhibited the expression of the luciferase gene containing the 3'-UTRs of osteopontin mRNA. Western blotting and Q-PCR indicated that miR-29b down-regulated the expression of osteopontin at the protein and mRNA levels. Taken together, our results demonstrate that miR-29b serves as a tumor proliferation suppressor, which suppresses esophageal cancer cell proliferation and arrest cell cycle by directly inhibiting osteopontin expression. The results show that miR-29b may be a novel therapeutic candidate target to slow esophageal cancer proliferation.