miR‐367 promotes proliferation and stem‐like traits in medulloblastoma cells

In medulloblastoma, abnormal expression of pluripotency factors such as LIN 28 and OCT 4 has been correlated with poor patient survival. The miR‐302/367 cluster has also been shown to control self‐renewal and pluripotency in human embryonic stem cells and induced pluripotent stem cells, but there is limited, mostly correlational, information about these pluripotency‐related mi RNA in cancer. We evaluated whether aberrant expression of such mi RNA could affect tumor cell behavior and stem‐like traits, thereby contributing to the aggressiveness of medulloblastoma cells. Basal expression of primary and mature forms of miR‐367 were detected in four human medulloblastoma cell lines and expression of the latter was found to be upregulated upon enforced expression of OCT 4A . Transient overexpression of miR‐367 significantly enhanced tumor features typically correlated with poor prognosis; namely, cell proliferation, 3‐D tumor spheroid cell invasion and the ability to generate neurosphere‐like structures enriched in  CD 133 expressing cells. A concurrent downregulation of the miR‐367 cancer‐related targets RYR 3 , ITGAV and RAB 23 , was also detected in miR‐367‐overexpressing cells. Overall, these findings support the pro‐oncogenic activity of miR‐367 in medulloblastoma and reveal a possible mechanism contributing to tumor aggressiveness, which could be further explored to improve patient stratification and treatment of this important type of pediatric brain cancer.