The Impact of Hyperthermia in Radiosensitivity of Human Cervical Carcinoma Cell Line HeLa

Introduction: The objective of this work was to investigate the therapeutic effect of a combination of hyperthermia at ۴۳oC exposured for ۲۰, ۴۰, ۶۰ min with ۶MeV electron beams at different radiation doses (۲, ۴, ۶ Gy) compared to radiation alone.   Materials and Methods: In this in vitro study, HeLa cells were exposed to either: ۶MeV electron beams at different doses (۲, ۴, ۶ Gy) and hyperthermia at ۴۳oC for ۲۰, ۴۰, ۶۰ min alone or electron beam followed by hyperthermia with ۲۰-minute interval. The effect of hyperthermia and radiation alone as well as a combination of radiation with hyperthermia on cell viability and cell survival were estimated using the trypan blue dye exclusion assay and MTT assay immediately and ۴۸ h after treatments, respectively. Results: The data obtained by trypan blue exclusion test showed that no significant reduction on cell viability when cells were treated RT (۶ MeV, ۲, ۴, ۶ Gy) and HT (۴۳oC, ۲۰, ۴۰, ۶۰ min) alone as well as RT followed by HT in comparison with control group (cells without treatment with the RT and HT). In addition, the data obtained by MTT assay showed significant cytotoxicity in the radiated groups compared to the control group. Also, our results showed HT alone did not effect on cytotoxicity. Moreover, our results showed that RT in combination with HT at ۴۳oC for ۲۰ min did not create significance cytotoxicity on HeLa cells in comparison with control group (group treated with radiation) (p>۰.۰۵). In contrast, RT in combination with HT at ۴۳oC for ۴۰,۶۰ min had significant cytotoxicity on HeLa cells in comparison with control group (group treated with radiation) (p<۰.۰۵). Conclusion: Our data suggest that combined treatment of ۶MeV electron beams (RT) and hyperthermia (HT) can result in radiosensitization of cervical cancer cells.