ABSTRACT:
Triple-negative breast cancer (TNBC) has aggressive characteristics, and lower overall- and disease-free survival compared to other breast cancer subtypes. TNBC tends to be apoptotic resistant, which allegedly related to dysregulation of anti-apoptotic Bcl-2 family proteins. Afzelin is a chemical compound that has anti-cancer potentials. The purposes of the study were analysing the effect of afzelin on apoptosis of MDA-MB-231 in vitro, and the interaction between afzelin and anti-apoptotic Bcl-2 family proteins through in silico approach. Apoptosis induced by afzelin was analysed by fluorescein isothiocyanate (FITC) Annexin V Apoptosis Detection Kit with propidium iodide (PI) through flow cytometry, with subsequent ANOVA analysis. Identification of pro-survival Bcl-2 family proteins and its key amino acid residues was based on literature reviews, followed with protein structures mining from Protein Data Bank (PDB). Afzelin chemical structure was obtained from PubChem. Reverse docking performed by Autodock Vina. Afzelin significantly increased apoptosis on MDA-MB-231 in a dose-dependent manner. The interactions of afzelin and anti-apoptotic Bcl-2 family proteins were based on BH3-mimetic mode of action. Reverse docking in BH3-hydrophobic groove showed that afzelin interact with Bcl-XL, Bcl-B, and MCL1, in the order from the highest to lower binding energy. Afzelin and corresponding BH3-only proteins formed hydrogen bonds with the same amino acid residues when interacted with Bcl-XL, Bcl-B, and MCL1. The outcomes predicted that afzelin induced apoptosis in MDA-MB-231 breast cancer cells through BH3 mimetic effect, particularly on Bcl-XL.