Radiation-induced effects on telomerase in gynecological cancer cell lines with different radiosensitivity and repair capacity.

PURPOSE

Telomerase activation in response to irradiation might enhance the radioresistance of cells. Thus, we have investigated radiation-induced effects on telomerase in six gynecological cancer cell lines, with different intrinsic radiosensitivity and capacity for sublethal damage repair (SLDR).

MATERIALS AND METHODS

Three endometrial adenocarcinoma (UM-EC-1, UT-EC-2B and UT-EC-3) and three vulvar squamous cell carcinoma (A431, UM-SCV-2 and UM-SCV-7) cell lines were irradiated with doses of 5, 10 and 25 Gy and the effects on telomerase were evaluated at 0.5, 6, 24 and 48 h post-irradiation. Telomerase activity was quantitatively measured by SYBR Green real-time telomeric repeat amplification protocol.

RESULTS

The most radioresistant cell line A431 had the strongest stimulatory effects (approximately 2.0 - 2.5-fold) on telomerase activity 24 and 48 h post-irradiation with the highest radiation doses. In contrast to that, telomerase activities in the highly radiosensitive cell line UT-EC-2B remained below the basal level throughout the 48-h period of post-irradiation with the highest doses, and even a decline to approximately 50% of the basal level was found 24 h after exposure. In other cell lines being either moderately or highly radiation resistant, telomerase activity levels in response to irradiation remained mainly at the basal level or gradually increased.

CONCLUSIONS

The present findings indicate that there might be a connection between the radiation-induced telomerase response and radiosensitivity. However, no correlation was found between the radiation-induced effects on telomerase and the sublethal damage repair capacity of the cells.