Novel Imidazo[2,1-b]oxazole Derivatives Inhibit Epithelial Cell Transformation and Triple Negative Breast Cancer Tumorigenesis.

ABSTRACT

BACKGROUND/AIM: Triple negative breast cancer (TNBC) is an aggressive type of breast cancer with limited targets for chemotherapy. This study evaluated the inhibitory effects of novel imidazo[2,1-b]oxazole-based rapidly accelerated fibrosarcoma (RAF) inhibitors, KIST0215-1 and KIST0215-2, on epithelial cell transformation and TNBC tumorigenesis. MATERIALS AND METHODS: Immunoblotting, BrdU incorporation assay, reporter gene assay, and soft agar assay analyses were performed. In vivo effects were studied using the BALB/c mouse xenograft model. RESULTS: KIST0215-1 and KIST0215-2 inhibited the RAFs-MEK1/2-ERK1/2 signalling pathway induced by EGF in MDA-MB-231 cells, which inhibited c-fos transcriptional activity and activator protein-1 transactivation activity. KIST0215-1 and KIST0215-2 also prevented neoplastic transformation of JB6 C141 mouse epidermal cells induced by EGF and consistently suppressed the growth of tumours formed by 4T1 cells in BALB/c mice. CONCLUSION: Inhibition of RAF kinases using KIST0215-1 and KIST0215-2 is a promising chemotherapeutic strategy to treat TNBC.