Autophagy: An overview and its roles in cancer and obesity.

Autophagy is a normal physiological process necessary for cellular homeostasis to maintain adequate levels of cellular components. It is essential to stabilize the source of energy during development and nutritional stress and plays the dual role of survival or cell killing in various diseases including cancer. The selectivity of the response to removal of selected organelles may vary according to the each type. Macroautophagy forms a double-membraned autophagosome around the organelle destined for processing. Microautophagy involves direct engulfment of the cellular components by lysosomal invagination. Chaperone mediated autophagy (CMA) is highly selective and is dependent on the chaperone hsc70 for its activity. The effects of all these types are implemented by autophagy related genes. In this review, the markers, activators, inhibitors biological effects and roles of the three classes of autophagy in cancer and obesity are discussed.