Radiobiological characterization of two human chemotherapy-resistant intermediate grade non-Hodgkin's lymphoma cell lines

Intermediate grade non-Hodgkin's lymphoma (IGNHL) is generally considered a radiosensitive tumor that can be controlled with moderate radiation doses. Cell-survival curves of cell lines derived from IGNHL have been typically described to exhibit small or no shoulder, implying inability to accumulate or repair sublethal radiation damage. We characterize in this report the c lonogenic radiation survival curves of two human IGNHL cell lines, WSU-DLCL 2 and SK-DHL2B, established from patients who expired after having exhibite d chemotherapy resistance of their tumors. The cells were irradiated with C o-60 radiation at a dose rate of 85-100 cGy/min and cell survival data were analyzed according to the linear quadratic model. The alpha/beta values fo r WSU-DLCL2 and SK-DHL2B cells are 2 and 8.6, respectively. The correspondi ng SF2 are 0.42 and 0.35, respectively. Both cell lines are able to repair radiation-induced sublethal damage. These data indicate that these cells ar e only moderately radiosensitive. (C) 1999 Wiley-Liss, Inc.