GLIPR1 inhibits the proliferation and induces the differentiation of cancer-initiating cells by regulating miR-16 in osteosarcoma.

Osteosarcoma is a common, highly malignant and metastatic bone cancer. Elucidation of the molecular mechanisms of osteosarcoma may further help us to understand the pathogenesis of the disease, and offer novel targets for effective therapies. Human glioma pathogenesis-related protein 1 (GLIPR1) has been found to be downregulated in human cancers. However, its roles have not been reported in osteosarcoma. In the present study, we demonstrated that GLIPR1 protein was downregulated in osteosarcoma. Its overexpression inhibited the proliferation, migration and invasion and induced the differentiation of cancer-initiating cells (CICs) in osteosarcoma. Moreover, GLIPR1 overexpression upregulated miR-16 in osteosarcoma cells. The upregulation suppressed proliferation, migration and invasion as well as induced differentiation of CICs in osteosarcoma. Thus, we conclude that GLIPR1 inhibited the proliferation, migration and invasion and induced the differentiation of CICs by regulating miR-16 in osteosarcoma. The present study provides direct evidence that GLIPR1 is a bona fide tumor suppressor and identified GLIPR1 and miR-16 as key components for regulating the proliferation, migration, invasion and CICs in osteosarcoma.