BBI608 induces apoptosis in mucoepidermoid carcinoma cells by targeting a post-transcriptional regulatory mechanisms of myeloid cell leukemia-1

Objectives: BBI608 has demonstrated antitumor activity in several human cancers. However, its efficacy against mucoepidermoid carcinoma (MEC) remains unexplored. This study investigated the antitumor potential of BBI608 in MEC cell lines.

Design: The antitumor activity of BBI608 in MC3 and YD-15 mucoepidermoid carcinoma (MEC) cell lines was assessed using trypan blue exclusion, Live/Dead, and sphere formation assays. Apoptotic effects were investigated via western blotting, 4',6-diamidino-2-phenylindole (DAPI) staining, Annexin V-fluorescein isothiocyanate/propidium iodide (V-FITC/PI) double staining, and reverse transcription-quantitative PCR.

Results: BBI608 exhibited growth-inhibitory effects in MEC cell lines, decreasing cell viability and sphere formation capacity while increasing cell death. BBI608-induced Apoptosis was confirmed by increased cleaved Caspase-3 and PARP expression, nuclear morphological changes characteristic of Apoptosis, and increased Annexin V positivity. Furthermore, BBI608 significantly downregulated Mcl-1 expression, which contributed to Apoptosis induction in MEC cells. This Mcl-1 downregulation appeared to be mediated by both proteasome-dependent protein degradation and translational regulatory mechanisms in MC3 and YD-15 cells, respectively.

Conclusion: These findings demonstrate that BBI608 effectively inhibits MEC cell proliferation in vitro by inducing Mcl-1-dependent Apoptosis. This suggests BBI608 warrants further investigation as a potential therapeutic agent for MEC.

Apoptosis; Carcinoma, mucoepidermoid; Health care; Myeloid cell leukemia sequence 1 protein; Napabucasin.