miR-143 inhibits osteosarcoma cell proliferation by down-regulating K-ras expression

Osteosarcoma is a primary bone malignancy, and it usually occurs in children and adolescents under 20 years old. Osteosarcoma is highly malignant, and the tumor cells will migrate to brain, lung, kidney, and other tissues. The mechanisms of osteosarcoma tumor genesis have not yet been fully studied. Some groups reported activation of Kras and abnormal expression of several miRNAs during osteosarcoma tumor progression. In this study, we focused on the regulatory relationship between miR-143 and Kras and its effects on osteosarcoma cell proliferation. Dual-luciferase reporter assay was performed to determine the regulatory relationship between miR-143 and Kras using wild type or mutated Kras 3'UTR inserted reporter vectors; Kras expression was detected by RT-qPCR and western blot after miR-143 mimic or miR-143 inhibitor transfection; CCK8 assay was used to check the role of miR-143 on osteosarcoma cell proliferation under different miR-143 expression levels. Dual-luciferase reporter assay showed that miR-143 targets the 3'UTR of Kras. High expression of miR-143 decreases Kras protein to 63%; while inhibited miR-143 expression elevates Kras protein to 1.67 fold. CCK8 assay revealed that increased miR-143 expression inhibits osteosarcoma cell proliferation. Kras is a target of miR-143; miR-143 inhibits osteosarcoma cell proliferation by repression of Kras.