Therapeutic Targeting of the Galectin-1/miR-22-3p Axis Regulates Cell Cycle and EMT Depending on the Molecular Subtype of Breast Cancer.

Breast cancer is a highly heterogeneous disease; hence, it is crucial to understand its biology and identify new targets for the development of effective treatments. Galectin-1 is known to play an oncogenic role in breast cancer progression. It is known that oncogenic factors can influence cancer progression through interactions with miRNAs. The purpose of this study is to identify the clinical significance and biological role of galectin-1 and miR-22-3p in cancer progression according to the molecular subtype of breast cancer. We analyzed the expression of galectin-1 and miR-22-3p using cancer tissues and the correlation with clinical pathological characteristics. In addition, we investigated the regulation of the cell cycle and EMT processes of cancer progression through the galectin-1/miR-22-3p axis using cell lines of different breast cancer subtypes. miR-22-3p negatively regulates galectin-1 expression and the two molecules have opposite patterns of oncogenic and tumor-suppressive functions, respectively; furthermore, these two molecules are associated with metastasis-free survival. Cell experiments showed that miR-22-3p overexpression and galectin-1 knockdown inhibited the proliferation and invasion of breast cancer cells. Galectin-1 regulates different cancer progression pathways depending on the molecular subtype. In hormone receptor-positive breast cancer cells, galectin-1 knockdown mainly inhibited cell cycle-related substances and induced G0/G1 arrest, whereas in triple-negative breast cancer cells, it suppressed molecules related to the epithelial-mesenchymal transition pathway. In conclusion, the miR-22-3p/galectin-1 axis regulates different cancer metastasis mechanisms depending on the specific molecular subtype of breast cancer, and miR-22-3p/galectin-1 axis modulation may be a novel target for molecular subtype-specific personalized treatment.