Overexpression of histone demethylase JMJD5 promotes metastasis and indicates a poor prognosis in breast cancer.

In this study, we showed the expression of JMJD5 was increased in breast cancer tissues and breast adenocarcinoma cell lines MCF-7 as well as triple negative breast cancer cell lines MDA-MB-231 compared with paired adjacent normal mammary tissues and normal mammary epithelial cell lines MCF-10A. The higher expression of JMJD5 was significantly corresponded with clinical stage, histological grade and lymph node metastasis. Overexpression of JMJD5 promoted cell invasion and induce EMT, while JMJD5 siRNA inhibits MDA-MB-231 cells invasion in vitro. Moreover, qChIP analysis revealed the Snail family proteins Snai1 was the direct target of JMJD5 in breast cancer cells. Luciferase reporter assays suggested that the overexpression of JMJD5 resulted in the activation of Snail1 promoter-driven luciferase reporter. The changes in the level of RNA and protein implied that the activation of Snail was the important mechanisms by which JMJD5 triggers metastasis. We also detected the higher expression of JMJD5 protein was an independent unfavorable biomarker for worse overall survival in breast cancer patients. Therefore, our results identified an important role for JMJD5 in breast cancer through the regulation of snail1.