Physiological and Genetically Engineered Expression Modulation Methods Do Not Affect Cellular Levels of the Heat...

Heat shock proteins (HSP) play a crucial role in the cellular responses during stressful conditions. In addition, HSP are involved in the regulation of a variety of important signaling pathways and processes as well as many pathological conditions, including cancer. In prostate cancer (PC), HSP60 is associated with poor differentiation and prognostic clinical parameters, such as high Gleason score, initial serum prostate-specific antigen levels, and lower cancer-specific survival. In this study, we investigated the regulation of HSP60 protein in PC.

LNCaP or PC3 cells were treated with androgens or transfected with vectors containing microRNA-1 (miR-1), HSP60, HSP60-specific short-hairpin RNA (shHSP60), or a miR-1 inhibitor. The change in HSP60 protein levels was examined using Western blot.

Treatment of PC cells with androgens did not alter the HSP60 protein levels. Modulation of miR-1 levels in LNCaP cells also did not affect the HSP60 protein. Furthermore, HSP60 levels could not be modified by overexpression or short hairpin RNA.

It was found that neither physiological factors, such as androgens and the HSP60-specific miR-1, nor overexpression and knockdown systems could influence the HSP60 protein levels. These results suggest an essential role of HSP60 in PC cells, as its protein expression status is regulated very precisely.