Caspases and Phytochemicals: An Important Link in Cancer Chemoprevention

The use of natural phytochemicals over other treatment regimens offers a safe and broad-spectrum strategy to overcome the incidence of cancer. Phytochemicals play a pivotal role for the induction of apoptosis in cancerous cells by activation of pro-apoptotic proteins and initiator caspases that in turn cleave and execute the activation of down-stream effector caspases. The caspases belong to the family of proteases that exist as inactive pro-forms or zymogens that on cleavage forms an active enzyme mediating apoptosis. Since cancer cells become insensitive to anti-growth and apoptotic signals, thus these caspases remain inactive in them. Array of phytochemicals belonging to different categories viz. phenols, flavonoids, terpenoids, alkaloids, stilbenes etc. are reported to trigger the activation of caspases in cancer cells by modulating various cell-death stimulating pathways. In the present review, we highlighted the role of different phytochemicals that execute the cleavage of caspases in cancerous cells by activating pro-apoptotic enzymes and proteins involved in the induction of apoptosis. This will assist to select and identify the molecular mechanisms of some effective phytochemicals targeting caspases in their chemopreventive ability.

Keywords: Alkaloids, Apoptosis, Bcl-2 Family, Cancer, Caspases, Chemoprevention, Cytoplasmic Proteins, Cysteinyl Specific Proteases, Effector Caspases, Epigenetic, Extrinsic Pathway, Flavonoids, Initiator Caspases, Intrinsic Pathway, Nuclear Proteins, Phenols, Phytoconstituents, Stilbenes, Terpenoids, Zymogens.