OMO-1 reduces progression and enhances cisplatin efficacy in a 4T1-based non-c-MET addicted intraductal mouse model for triple-negative breast cancer.

c-MET is considered a driver of cancer progression, impacting tumor growth and tumor-supporting stroma. Here, we investigated the therapeutic efficacy of OMO-1, a potent and selective c-MET inhibitor, in an immunocompetent intraductal mouse model for triple-negative breast cancer (TNBC). OMO-1 reduced non-c-MET addicted 4T1 tumor progression dose dependently as monotherapeutic and provided additional disease reduction in combination with cisplatin. At the stromal level, OMO-1 significantly reduced neutrophil infiltration in 4T1 tumors, promoted immune activation, and enhanced cisplatin-mediated reduction of tumor-associated macrophages. OMO-1 treatment also reduced 4T1 tumor hypoxia and increased expression of pericyte markers, indicative for vascular maturation. Corroborating this finding, cisplatin delivery to the 4T1 primary tumor was enhanced upon OMO-1 treatment, increasing cisplatin DNA-adduct levels and tumor cell death. Although verification in additional cell lines is warranted, our findings provide initial evidence that TNBC patients may benefit from OMO-1 treatment, even in cases of non-c-MET addicted tumors.