Residual telomerase activity: a marker of cell survival after exposure to gamma radiation in vitro.
BACKGROUND
Residual telomerase activity (TA) could be used as a marker of malignant or normal cell survival after exposure to cytotoxic agents. Therefore TA after treatment with ionizing radiation was used in a radiosensitivity assay.


METHODS
Radiosensitive MOLT-4 and relatively radioresistant Jurkat leukemia cells or normal peripheral blood mononuclear cells (MNC) were irradiated with 5-160 Gy. Cell count, MTT assay and telomerase activity were evaluated on day 3 and clonogenic assay on day 10.


RESULTS
In Jurkat cells, irradiation inhibited tumor growth and total TA per culture (TA/culture), but up-regulated TA per viable cell (TA/cell). TA/culture and TA/cell were profoundly depressed by irradiation of MOLT-4 or phytohemagglutinin-activated MNC.


CONCLUSIONS
Susceptibility of normal or neoplastic cells to high-dose radiation can be monitored by evaluating residual TA/culture. In some cases, however, difficulties in the interpretation of the results could stem from radiation-induced increase of TA/cell, as observed for the Jurkat cell line.
Turriziani
Mario
M
Department of Internal Medicine, Tor Vergata University, Via Montpellier 1, 00133 Rome, Italy.
Di Giacomo
Anna Maria
AM
Cardillo
Anna
A
Torino
Francesco
F
Tentori
Lucio
L
Nasuti
Paola
P
Massara
Maria Chiara
MC
Roselli
Mario
M
Bonmassar
Enzo
E
De Vecchis
Liana
L
D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000032:analysis; D002470:Cell Survival / Q000528:radiation effects*; D005434:Flow Cytometry; D005720:Gamma Rays; D006801:Humans; D066298:In Vitro Techniques; D019169:Jurkat Cells; D015458:Leukemia, T-Cell; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects; D010835:Phytohemagglutinins / Q000494:pharmacology; D012016:Reference Values; D019098:Telomerase / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D010835:Phytohemagglutinins; D019098:Telomerase