Molecular mechanism of miR-34b-5p and RNA binding protein HuR binding to lncRNA OIP5-AS1 in colon cancer cells.

Colon cancer (CC) is a leading cause of cancer-related death. Long non-coding RNA OIP5-AS1 (lncRNA OIP5-AS1) expression pattern has been studied in many cancers. We aimed to identify the mechanism of lncRNA OIP5-AS1 in CC development. OIP5-AS1 expression pattern in CC tissues and cells was detected and the relation between OIP5-AS1 level and CC prognosis was analyzed. The proliferation, migration and invasion of CC cells were detected after silencing or overexpression of OIP5-AS1. Tumor xenograft in nude mice was established to verify the effect of OIP5-AS1 in vivo. The interaction between HuR protein and OIP5-AS1 and the interaction of miR-34b-5p with HuR and OIP5-AS1 were measured. OIP5-AS1 was highly expressed in CC and associated with poor prognosis. Silencing OIP5-AS1 inhibited CC cell malignant behaviors and inhibited the growth rate and tumor weight. In the mechanism, HuR bound to OIP5-AS1 and stabilized OIP5-AS1 expression. Both miR-34-5p and HuR bind to OIP5 and oppositely affect its expression. miR-34b-5p inhibited the proliferation and invasion of CC cells by inhibiting OIP5-AS1 and PI3K/Akt pathway. miR-34b-5p inhibited CC growth by inhibiting OIP5-AS1. Collectively, miR-34b-5p targets HuR and miR-34b-5p binds to OIP5-AS1 with HuR, thus inhibiting OIP5-AS1 and PI3K/Akt pathway and CC progression.