Lysosomes and autophagy in cell death control.

Lysosomal hydrolases participate in the digestion of endocytosed and autophagocytosed material inside the lysosomal/autolysosomal compartment in acute cell death when released into the cytosol and in cancer progression following their release into the extracellular space. Lysosomal alterations are common in cancer cells. The increased expression and altered trafficking of lysosomal enzymes participates in tissue invasion, angiogenesis and sensitization to the lysosomal death pathway. But lysosomal heat-shock protein 70 locally prevents lysosomal-membrane permeabilization. Similarly, alterations in the autophagic compartment are linked to carcinogenesis and resistance to chemotherapy. Targeting these pathways might constitute a novel approach to cancer therapy.