INVITRO CYTOTOXICITY OF HUMAN RECOMBINANT TUMOR-NECROSIS-FACTOR ALPHA IN ASSOCIATION WITH RADIOTHERAPY IN A HUMAN OVARIAN-CARCINOMA CELL-LINE

It has been speculated that tumor necrosis factor α (TNF-α) may decrease the cytotoxicity of radiotherapy by increasing the scavenging of toxic superoxide radicals. Because of the possible clinical implications, the cytotoxicity of TNF-α in combination with radiotherapy (RT) was compared with that of RT alone in a human ovarian cancer cell line. NIH:OVCAR-3 cells were incubated with TNF-α at 10.0, 1.0, 0.1, and 0.01 μg/ml. Plates were divided into two groups; one received 150 cGy of radio-therapy and the other received no further therapy. Seventy-two hours later, supernatants were aspirated and viable cells were stained with a 1% solution of crystal violet. Survival of cells treated with RT plus TNF-α was expressed as a percentage of surviving irradiated controls. Analysis of results revealed minimal additive cell killing effect between TNF-α and radiotherapy at all concentrations of tumor necrosis factor, with the greatest difference noted in the group treated with 10 μg/ml TNF-α. A continued radiotherapy dose-response study with TNF-α showed a similar additive, not radioprotective, effect. This may have implication as a potentiator of RT in some human tumors. © 1990.