Hsps 70 and 105 associate with a group of hsp90 client proteins that are selectively found in human breast cancer

Abstract

This study investigated the interaction of heat shock proteins (hsps) and their client proteins in tumour and normal human breast tissue. The objective of the study was to discover hsp interactions specific to cancer cells. Hsps have been observed to be over-expressed in a range of human cancers. Of which hsps 70, 90 and others have been noted to be up-regulated in breast cancer. Up-regulation of these hsps has been shown to predict patient prognosis and response to therapies [1, 2]. The majority of hsp90's client proteins are signal transduction proteins. In addition, hsp90 is essential for cellular survival and has been proposed to participate in all 6 "hallmarks of cancer" [3]. Hsp90 inhibitors are under intense investigation and are currently in phase III clinical trials for the treatment of cancer. Hsp90 is known to associate with other hsps in the assembly and function of chaperone complexes. These experiments examined the hsp chaperone complexes and the effect of geldanamycin (an hsp90 inhibitor) on these complexes in human breast cancer