Effect of miR-143 on the apoptosis of osteosarcoma cells

As one common malignant bone cancer, osteosarcoma is mainly occurred in young people with increasing incidences. Current treatment of osteosarcoma includes surgery and chemo-/radio-therapy. Due to the unclear pathogenesis mechanism, the overall treatment efficacy is still not satisfactory. As anti-apoptotic molecule Bcl-2 has been suggested to be related with osteosarcoma and is regulated by miR-143, we thus investigated the correlation between miR-143 and Bcl-2 in osteosarcoma patients, in an attempt to elucidate the role of miR-143 in cancer occurrence. Real-time fluorescent RT-PCR was used to quantify expression levels of miR-143 and Bcl-2 from a total of 5 osteosarcoma patients, along with protein contents determination by Western blotting. In vitro study was also performed to detect Bcl-2 expression and cell apoptosis via silencing or over-expressing miR-143 in cultured osteosarcoma cells. MiR-143 showed down-regulation in osteosarcoma tissues. Bcl-2, however, had elevated expression in cancer cells when compared to adjacent tissues (P<0.05). In cultured cells, Bcl-2 expression level was also potentiated after knock-down of miR-143, while those cells with miR-143 over-expression had depressed Bcl-2 levels. Those cells transfected with miR-143 mimics had higher percentage of apoptotic cells. MiR-143 can regulate the expression of Bcl-2 gene in osteosarcoma cells, and mediate the apoptotic process, thereby playing a critical role in the pathogenesis of osteosarcoma.