Thermally induced injury and heat-shock protein expression in cells and tissues.

Heat-shock proteins (HSPs) are critical components of a cell's defense mechanism against injury associated with adverse stresses. Initiating insults, such as elevated or depressed temperature, diminished oxygen, and pressure, increase HSP expression and can protect cells against subsequent, otherwise lethal, insults. Although HSPs are very beneficial to the normal cell, cancer cells can also use HSPs in response to stresses associated with various therapies (hyperthermia, chemotherapy, radiation), mitigating injury incurred by these treatments. Hyperthermia is a common treatment option for prostate cancer. HSPs can be induced in regions of the tumor where temperatures are insufficient to cause lethal thermal necrosis. Elevated HSP expression can enhance tumor cell viability and impart increased resistance to subsequent chemotherapy and radiation treatments, thereby promoting tumor recurrence. An understanding of the structure, function, and thermally stimulated HSP kinetics and cell injury for prostate cancer cells is essential to designing effective hyperthermia protocols. Measured thermally induced cellular HSP expression and injury data can be employed to develop a treatment planning model for optimization of the tissue response to therapy based on accurate prediction of the HSP expression and cell damage distribution.