IL-6 Triggers the Migration and Invasion of Oestrogen Receptor-Negative Breast Cancer Cells via Regulation of Hippo Pathways.

Breast cancer is one of the major challenges for women's health. However, the role and mechanisms of interleukins (ILs) on the progression of breast cancer are not well illustrated. Our present study revealed that the expressions of IL-6 and IL-8 were significantly increased in oestrogen receptor-negative (ER-) breast cancer cells. Increased expression of IL-6 was observed in 83.9% (26/31) ER- breast cancer tissues as compared with their matched adjacent normal tissues. In vitro studies indicated that IL-6 can significantly promote the migration and invasion of ER- breast cancer cells via increasing the dephosphorylation, nuclear translocation and transcriptional activities of YAP in breast cancer cells. Knockdown of YAP can attenuate IL-6-induced migration and invasion of cancer cells, suggesting that YAP plays an essential role in IL-6-induced malignancy of breast cancer cells. Furthermore, IL-6 treatment also decreased the phosphorylation of LATS1/2. The knockdown of LATS1/2 synergistically suppressed si-IL-6-induced deactivation of YAP. Targeted inhibition of IL-6/YAP can significantly suppress the invasion of ER- breast cancer cells. Collectively, our study revealed that IL-6 can trigger the malignancy of breast cancer cells via activation of YAP signals. Targeted inhibition of IL-6/YAP might be a novel therapeutic approach for the treatment of ER- breast cancer.