Anti-Proliferative and Pro-Apoptotic Effects of (-)-Epigallocatechin-3- Gallate Encapsulated in Chitosan Nanoparticles on Human Prostate Carcinoma Cells

(-)-epigallocatechin-3-gallate (EGCG), the major polyphenol of green tea, has shown excellent effects in preventing, as well as treating, many cancers including prostate cancer (PCa) in preclinical model systems. However its applicability to humans has met with limited success due to several issues including its limited bioavailability. We employed the use of nanotechnology to improve the outcome of cancer chemoprevention and coined the concept ‘nanochemoprevention’. Recently, we reported the synthesis, characterization and efficacy assessment of a formulation of chitosan encapsulating EGCG (Chit-nanoEGCG) for treatment of PCa in a xenograft model [1]. Here we show the efficacy of this nanoformulation in human PCa cells for inhibition of cell growth, induction of apoptosis, and inhibition of the colony formation. We further demonstrate that the encapsulated EGCG retains its mechanistic identity for induction of apoptosis. We observed that chit- nanoEGCG treatment induces apoptosis and also results in growth arrest of the cells in S phase and the cell cycle-regulatory molecules operative in the G1/S phase of the cell cycle were significantly modulated. All these effects were seen at much lower doses in chit-nanoEGCG treated cells as compared to the native agent. Collectively, chit- nanoEGCG could prove useful for preventing and/or treating human PCa.