Withania somnifera-derived phytochemicals as Bcl-B inhibitors in cancer therapy: A computational approach from byte to bench to bedside

Abstract

Cancer is the second foremost cause of fatalities associated with non-communicable diseases across the globe, affecting multiple organs and often necessitating costly treatments with adverse side effects. Apoptosis, the body's natural cell death process, plays a crucial role in the prevention of cancer, but it's often disrupted in cancer cells, allowing uncontrolled proliferation. Restoring apoptosis in cancer cells is one of the promising therapeutic strategies to curb tumor growth and enhance clinical outcomes. Bcl-B, an anti-apoptotic protein within the Bcl-2 family, interacts with Bax to mitigate apoptosis, indicating it as a druggable target for cancer therapy. There's a critical need for natural, cost-effective alternatives with minimal adverse effects to reduce morbidity rates of cancer patients. Plant-based immunoprotective medications, particularly from sustainable sources like known medicinal plants, offer substantial potential for cancer treatment. This study involves comprehensive in silico approaches (byte) to evaluate the inhibition potential of the phytochemicals derived from Withania somnifera against the anti-apoptotic Bcl-B protein. Research into Bcl-B's binding affinity with 80 phytochemicals from this plant aims to identify interaction sites for promising anticancer agents. This study's focus on Bcl-B protein highlights its potential in modulating apoptotic pathways and exploring novel anti-cancer therapeutics. Through comprehensive screening based on drug-likeness and pharmacokinetic properties, combined with in-house virtual screening, molecular docking, molecular dynamics simulations, and MM/PBSA-based binding free energy analysis, three promising candidate inhibitors—Withanolide L (IMPHY009438), Withanolide M (IMPHY003143), and Withanolide A (IMPHY000090)—were identified and prioritized. These candidates showed favorable estimated binding free energy values, along with desirable drug-likeness and pharmacokinetic profiles. The results demonstrated that the selected and prioritized phytochemicals, Withanolide L, Withanolide M, and Withanolide A display comparable efficacy to Obatoclax (CID: 11404337) and other known synthetic, semi-synthetic, and natural inhibitors of Bcl-2 family proteins. These findings establish a strong bench foundation for further experimental validation and bedside application, potentially offering an alternative natural approach to cancer therapy.