Oncogenic Transformation and Cell Lysis in C3H/10T1/2 Cells and Increased Sister Chromatid Exchange in Human Lymphocytes by Nickel Subsulfide1

We have scored frequency of transformation and appear ance of the oncogenic marker "long microvilli" in mouse em bryo fibroblast C3H/10TV2 cells in culture for the compound NI3S2. Furthermore, we have scored for Ni3S2-induced sister chromatid exchange in cultured human lymphocytes. Nickel subsulfide in moderate doses caused morphological transfor mation to type I, II, and III foci and induced long microvilli on the cells in the transformed cultures, demonstrating oncogenic transforming ability. Higher doses led to cell lysis after a lag period. The carcinogenic potency of Ni3S2 in this system was not as strong as that of methylcholanthrene. Ni3S2 increased the sister chromatid exchange frequency in human lymphocytes in a marginal, not dose-dependent way. The increased sister chromatid exchange may indicate that the carcinogenic effect of Ni3S2 is genetic rather than epigenetic.