The Effect of Hyperthermia on Survival Fraction of DU 145 Human Prostate Carcinoma Cell Line in Monolayer and Spheroid Culture

Background: Hyperthermia (also called thermal therapy or thermotherapy) is a type of cancer treatment in which body tissue is exposed to high temperatures (up to 113°F). Research has shown that high temperatures can damage and kill cancer cells, usually with minimal injury to normal tissues. For many years, biologists have investigated cancer by using monolayer cell culture. It is becoming more and more apparent that two-dimensional cell culture (monolayer) can not completely represent the real structure and characteristics of three-dimensional in vivo solid tumors. These spheroids resemble in vivo tumor models in several aspects. Therefore, studying growth characteristics and behavior of spheroids is beneficial in understanding the behavior of tumors under various experimental conditions. Methods: In this work we have studied and analyzed the in vitro response of human prostatic carcinoma cell line DU 145 from monolayer and spheroid culture to hyperthermia. For this purpose the DU 145 cells were cultured either as monolayer or spheroids. The thermal response was judged by the survival fraction of colony forming cells in spheroids or monolayer culture following heat treatment. Results: The result of Survival curves has shown that heating cells at 40°C and 41°C has no significant effect on cell viability and survival fraction at various times of heating but heating the cells at 42°C and 43°C in long period of heat treatment reduce the viability and survival fraction particularly. Conclusion: Heat shock at 44°C and 45°C has great effect on this cell viability and survival fraction but in any time and temperature, spheroids were more resistant than monolayer’s.