Sesamol Induces Apoptosis by Altering Expression of Bcl-2 and Bax Proteins and Modifies Skin Tumor Development in Balb/c Mice

Background: Chemoprevention using natural agents has emerged as a new and promising strategy for reducing cancer burden. Sesamol, a water soluble lignin, is a potent antioxidant with potential anticancer activities. Its small size (molecular weight: 138.34g) coupled with easy permeability (log P: 1.29) results in its excessive systemic loss therefore, compromising local bioavailability. Furthermore, irritant nature of sesamol limits its application on skin per se. Objective: Present study aims to evaluate chemopreventive efficacy of free and encapsulated (SLNs) sesamol, at gross and molecular level, in DMBA induced skin cancer animal model. Methods: Evaluation is done in terms of tumor burden quantification, histological evaluation of skin, determination of oxidative stress, and quantification of apoptotic proteins, bcl-2 and bax, using both western blot analysis and immunofluorescence studies. Results: Sesamol administration (both in free and encapsulated form) significantly decreased the tumor burden and lipid peroxidation level and increased anti-oxidant levels, thereby hampering the development and promotion of skin tumors. Further, downregulation of bcl-2 and stimulation of bax protein expression on treatment with both free and encapsulated sesamol was responsible for the induction of apoptosis in tumor cells. Encapsulating sesamol into SLNs not only reduced its irritant nature which limits its direct topical application but also improved its local targeting to skin. Conclusion: Both free and encapsulated sesamol demonstrated the inhibition of tumor progression by inducing skin cell apoptosis via bcl-2/bax mediated pathway.