Long non-coding RNA OSTM1-AS1 promotes renal cell carcinoma progression by sponging miR-491-5p and upregulating MMP-9

Long noncoding RNAs (lncRNAs) have been recognized as essential regulators in various human malignancies. Hundreds of lncRNAs were known to be abnormally expressed in renal cell carcinoma (RCC) through a lncRNA expression microarray, among which lncRNA OSTM1 antisense RNA 1(OSTM1-AS1) was revealed as one of the most abundant lncRNAs. However, the function of OSTM1-AS1 in RCC remains unknown. Here, we examined OSTM1-AS1 functional roles and mechanism in RCC development. OSTM1-AS1 expression was significantly highly expressed among RCC tissue specimens and cell lines. Functionally, OSTM1-AS1 knockdown significantly suppressed cell proliferation, migration along with metastasis of RCC cells. Mechanistically, miR-491-5p was targeted via OSTM1-AS1, and down-regulation of miR-491-5p reversed OSTM1-AS1 knockdown impact on RCC migration and invasion. MMP-9 was targeted via miR-491-5p, and MMP-9 overexpression reversed miR-491-5p or OSTM1-AS1 knockdown impact on cell migration and invasion. MMP-9 abundance was decreased by OSTM1-AS1 silence, that was reduced by miR-491-5p deficiency. Importantly, our investigation revealed that OSTM1-AS1 has the ability to interact with miR-491-5p, thereby increasing the MMP-9 expression. The in vivo trial demonstrated that OSTM1-AS1 suppression resulted in tumor growth inhibition among nude mice. In summary, our findings indicate, for the first time, at least to the best of our knowledge, that OSTM1-AS1 serves as an oncogene among RCC by promoting proliferation, invasion, and metastasis through its targeting of the miR-491-5p/MMP9 axis. Therefore, this axis could represent a promising alternative therapeutic target for RCC treatment.