miR-491-5p inhibits osteosarcoma cell proliferation by targeting PKM2

Increasing evidence has indicated that microRNAs (miRNAs/miRs) are associated with tumorigenesis and the development of numerous cancer types. Previous studies have suggested miRNA-491-5p is downregulated in osteosarcoma (OS) and functions as a tumor suppressor. However, the biological roles and underlying mechanisms associated with miR-491-5p function in OS require further exploration. In the present study, it was demonstrated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) that miR-491-5p was downregulated in 36 pairs of OS tissues, compared with in adjacent normal bone tissues. Furthermore, CCK-8 and colony formation assays indicated that miR-491-5p mimics suppressed OS cell proliferation. However, an miR-491-5p inhibitor enhanced cell proliferation. In addition, luciferase reporter assays, RT-qPCR and western blot analysis demonstrated that PKM2 was a direct target of miR-491-5p. The miR-491-5p mimic inhibited the mRNA and protein expression of PKM2, while the miR-491-5p inhibitor promoted PKM2 mRNA and protein expression. In addition, PKM2 overexpression reversed the proliferation-inhibiting effects of miR-491-5p in OS cells. Therefore, these results indicated that miR-491-5p serves as a tumor suppressor in OS cells, which may be important in OS treatment.