Heat shock proteins, cell survival and drug resistance: the mitochondrial chaperone TRAP1, a potential novel target for ovarian cancer therapy

Protein homeostasis is a highly complex network of molecular interactions governing the health and life span of the organism. Molecular chaperones, mainly heat shock proteins (HSP) and other stressinducible proteins abundantly expressed in multiple compartments of the cell, are major modulators of protein homeostasis. TRAP1 is a mitochondrial HSP involved in protection against oxidant-induced DNA damage and apoptosis. It was recently described as a component of a mitochondrial pathway selectively up-regulated in tumor cells which antagonizes the proapoptotic activity of cyclophilin D, a mitochondrial permeability transition pore regulator, and is responsible for the maintenance of mitochondrial integrity, thus favoring cell survival. Interestingly, novel TRAP1 antagonists cause sudden collapse of mitochondrial function and selective tumor cell death, suggesting that this pathway may represent a novel molecular target to improve anticancer therapy. Preliminary data suggest that TRAP1 may be a valuable biomarker in ovarian cancers: in fact, TRAP1 levels are signi!cantly higher in cisplatin-resistant ovarian tumors and ovarian carcinoma cell lines. Conclusions. While major advances have been made in understanding the genetics and molecular biology of cancer, given the considerable heterogeneity of ovarian cancer, the introduction of novel targeted therapies and the consequent selection of treatments based on the molecular pro!le of each tumor may have a major impact on the management of this malignancy and might contribute to building a new era of personalized medicine.