Fig. 6.

miR-629-3p promotes tumorigenesis and lung metastasis of triple-negative breast cancer (TNBC). a, b, and c Stably engineered miR-629-3p-inhibiting MDA-MB-231 cells (Lv-anti-miR-629) and pre-miR-629-expressing MCF-7 cells (Lv-miR-629) were inoculated into the mammary gland fat pads of nude mice. The weight and volume of mammary tumors generated from Lv-anti-miR-629 were significantly less than those from scrambled 1 MDA-MB-231 cells (Lv-Scr1). Likewise, compared with scrambled 2 MCF-7 cells (Lv-Scr2), Lv-miR-629 cells showed a significant increase in tumor growth. d The number of macroscopically visible pulmonary metastatic nodules per mouse was counted. Lv-anti-miR-629 decreased the number of metastatic foci in lungs dramatically in mice with MDA-MB-231 tumors. However, Lv-miR-629 increased the lung metastases in mice with MCF-7 tumors. e Lung metastases were confirmed by hematoxylin and eosin staining (original magnification × 200). f Arrows indicate visible metastatic nodules in representative gross specimens of lung sections. g Immunohistochemical analysis further substantiated that miR-629-3p targeted leukemia inhibitory factor receptor (LIFR) in both primary tumors and lung metastases (original magnification × 400; insets, original magnification × 200). * P < 0.05 and ** P < 0.01