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


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.
Kurvinen
Kaisa
K
Department of Oral Pathology and Oral Radiology, Institute of Dentistry and MediCity Research Laboratory, Faculty of Medicine, University of Turku, Turku, Finland.
Rantanen
Virpi
V
Syrjänen
Stina
S
Johansson
Bo
B
D045744:Cell Line, Tumor; D004249:DNA Damage; D004260:DNA Repair; D004273:DNA, Neoplasm / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004789:Enzyme Activation / Q000528:radiation effects; D005260:Female; D005833:Genital Neoplasms, Female / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D011829:Radiation Dosage; D011836:Radiation Tolerance; D019098:Telomerase / Q000378:metabolism* / Q000528:radiation effects*
D004273:DNA, Neoplasm; D019098:Telomerase