Human Melanoma Cells:Relationship Between Their Radiosensitivity and the Repair of Potentially Lethal Damage

摘要

AbstractFrom clinical experience, malignant melanomas are generally considered to be radioresistant. To explain this impression, the hypothesis had been advanced that the melanoma cells in a tumor are inherently resistant and that they are so because they are particularly effective in repairing potentially lethal damage. We have examined this idea with several lines of melanoma cells, and we have compared the responses of these cells to those of normal and ataxia telangiectasia fibroblasts (both SV40 transformed). The single‐dose responses of the melanoma cells were found to cover a large range. The most sensitive had a response similar to that of normal fibroblasts, but the most resistant required a dose for 10 survival to be 2–3 times larger. Correlated with this range in response, we found the sensitive melanoma cells to be deficient in both the fast and slow repair of potentially lethal damage compared to resistant melanoma cells. Sensitive and resistant melanoma cells survived ultraviolet light exposure equally well, however. We conclude that the repair of potentially lethal damage is important to the X‐ray response of melanoma cells, but that the degree of such repair correlates with the inherent sensitivity of such cells. Consistent with many other types of observations, we also note that the mechanism of lethality by ionizing radiation is fundamentally different from that of ultraviolet light. © 1993 Wiley‐L