Galectin-1 knockdown in carcinoma-associated fibroblasts inhibits migration and invasion of human MDA-MB-231 breast cancer cells by modulating MMP-9 expression.

Carcinoma-associated fibroblasts (CAFs) play central roles in facilitating tumor progression and metastasis in breast cancer. Galectin-1 (Gal-1), a marker of CAFs, was previously reported to be associated with tumorigenesis and metastasis of various types of tumors. The aim of this study is to investigate the role of Gal-1 in CAF-mediated breast cancer metastasis and its underlying molecular mechanisms. Our results showed that CAFs isolated from human breast tumor tissues expressed higher level of Gal-1 compared with paired normal fibroblasts, and the conditioned medium (CM) of CAFs significantly induced the migration and invasion of human MDA-MB-231 breast cancer cells. Knockdown of Gal-1 in CAFs dramatically inhibited CAF-CM-induced cell migration and invasion, probably by inhibiting the expression of matrix metalloprotein 9 (MMP-9). Our findings demonstrate that Gal-1-regulated CAFs activation promotes breast cancer cell metastasis by upregulating MMP-9 expression, which indicated that Gal-1 in CAFs might be a potential novel target for breast cancer therapy.