MicroRNA-26a inhibits osteosarcoma cell proliferation by targeting IGF-1

Abstract

There are still controversies about the roles of microRNA-26a (miR-26a) in human malignancies, as it is a tumor suppressor in breast cancer, gastric cancer, and hepatocellular carcinoma, but is an oncogene in glioma and cholangiocarcinoma. Until now, the function of miR-26a in osteosarcoma remains largely elusive. Here, we found that miR-26a was downregualted in osteosarcoma tissues. Using in vitro and in vivo assays, we confirmed that miR-26a could inhibit the abilities of in vitro proliferation and suppress in vivo tumor growth in mouse model. Furthermore, we identified insulin-like growth factor 1 (IGF-1) as a novel and direct target of miR-26a and revealed that miR-26a exerted its tumor-suppressor function, at least in part, by inhibiting IGF-1 expression. These findings contribute to our understanding of the functions of miR-26a in osteosarcoma.

Bone cancer: small RNA offers drug target

A small regulatory molecule called microRNA-26a suppresses bone cancer by blocking the expression of a growth factor. MicroRNA-26a seems to play a different role in different kinds of cancer: it inhibits tumors of the breast, stomach, and liver, but promotes proliferation in cancers of the brain and bile ducts. Xinyu Tan and colleagues from the Third Affiliated Hospital of Southern Medical University in Guangzhou, China, examined the function of microRNA-26a in osteosarcoma, a type of bone cancer. Using cell lines and mouse models, they found that microRNA-26a serves as a tumor suppressor in this disease, and works, at least in part, by inhibiting a growth factor called insulin-like growth factor 1. These results offer a window into the molecular mechanism of osteosarcoma development, and suggest that boosting levels of microRNA-26a could help treat patients.

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