Verticillin A increases the BIMEL/MCL-1 ratio to overcome ABT-737-resistance in human colon cancer cells by targeting the MEK/ERK pathway.

ABT-737, a small molecule BH-3 mimetic, is less effective against human colon cancers due to its resistance. Verticillin A is a natural compound, which was previously purified from verticillium -infected mushrooms. Hence, we aimed at overcoming the ABT737 resistance observed in CRC tumors by combining Verticillin A with ABT-737 and figuring out the potential mechanism. In this study, we observed that Verticillin A could sensitize colon cancer to ABT-737-induced cell death through induction of mitochondrial-dependent apoptosis. Verticillin A could significantly increase the BIMEL/MCL-1 ratio to overcome ABT737 resistance through the suppression of the MEK/ERK pathway. In addition, up-regulation of BIM protein levels to activate BAX translocation results in apoptosis induction. Altogether, our work suggested the potential application of Verticillin A as a MEK inhibitor in BH3-mimetic-based therapy. • Verticillin A increases BIM EL / MCL-1 ratio to strengthen sensitivity of colon cancer cells to ABT-737. • Verticillin A suppresses the MEK/ERK pathway to up-regulate BIM and subsequently activates BAX translocation resulting in apoptosis. • Verticillin A has the potential application as an MEK inhibitor in BH3-mimetic-based therapy in human cancers. [ABSTRACT FROM AUTHOR]