MFAP5 promotes basal-like breast cancer progression by activating the EMT program

Human basal-like breast cancer (BLBC) is an aggressive malignancy with poor prognosis. Since most current treatments are ineffective, there is an urgent need to identify therapeutic targets for BLBC. Microfibrillar-associated protein 5 (MFAP5) plays an important role in the integration of elastic microfibers and the regulation of endothelial cell behaviors. We previously demonstrated that MFAP5 was significantly overexpressed in BLBC tissues and associated with poor metastasis-free survival of patients with BLBC. However, the detailed role of MFAP5 in BLBC is unclear. Thereby, the current study aimed to investigate the underlying function of MFAP5 in BLBC.Functional analyses were conducted for the role of MFAP5 in BLBC in vitro and in vivo.Overexpression of MFAP5 resulted in a significant increase in the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) markers in BLBC in vitro and in vivo. In addition, other metastasis animal models by tail intravenous injection of BT20 cells further confirmed that MFAP5 overexpression promoted BLBC proliferation and BT20 cells metastasis. We found that the TGF-β or Notch inhibitor significantly reversed the tumorigenicity and metastasis of MFAP5-induced BLBC cells.Our findings suggest that MFAP5 may promote EMT in BLBC metastasis via the TGF-β/Notch pathway.