Decreased HCRP1 promotes breast cancer metastasis by enhancing EGFR phosphorylation

Previous study showed that hepatocellular carcinoma related protein 1 (HCRP1) is decreased in breast cancer. HCRP1 expression is inversely related to epithelial growth factor receptor (EGFR) in breast cancer tissues, and patients with breast cancer expressing lower HCRP1 tended to suffer a shorter life expectancy. However, the detailed biological functions of HCRP1 in breast cancer as well as the interaction between HCRP1 and EGFR remain unexplored. In this study, we examined HCRP1 expression in breast cancer tissues and cell lines by western blot. Thereafter, we performed transwell migration and matrigel invasion assays after siRNA interference and lentiviral vector of HCRP1 infection. To further investigate the interaction between HCRP1 downregulation and EGFR signaling pathway, we evaluated the phosphorylation status of EGFR, Erk1/2 and Akt by western blot following HCRP1-siRNA transfection. Moreover, we investigated the in vivo functions of HCRP1 using a breast cancer xenograft model. We found that HCRP1 depletion significantly promoted breast cancer migration and invasion while HCRP1 overexpression produced an opposite effect. In addition, HCRP1 depletion decreased EGFR degradation and enhanced phosphorylation of EGFR. Interestingly, HCRP1 depletion also led to insensitivity to EGFR inhibitors treatment. The in vivo experiment confirmed the metastasis inhibition function of HCRP1. The present data indicate that HCRP1 inhibits breast cancer metastasis through downregulating EGFR phosphorylation.