Loss of the Opa interacting protein 5 inhibits breast cancer proliferation through miR-139-5p/NOTCH1 pathway.

Opa interacting protein 5 (OIP5) has been reported to be over-expressed in several kinds of human cancer. However, the biological function and clinical significance of OIP5 in human breast cancer remains unknown. In this study, we found that OIP5 was notably over-expressed in breast cancer tissues compared with their corresponding nontumorous tissues. Statistical analysis showed a significant correlation of OIP5 expression with advanced clinical stage. Ablation OIP5 inhibited the proliferation of breast cancer cells. OIP5 over-expression inhibited hsa-miR-139-5p expression, antagonized its functions and led to the de-repression of its endogenous target NOTCH1, which was a core oncogene in promoting breast cancer progression. Our results suggested that OIP5 is a potential diagnosis biomarker and therapeutic target for breast cancer.