Assay evaluability of drug testing systems determined with human renal carcinoma cell lines

Summary

Of 39 human kidney carcinoma transplanted to nude mice, four tumor lines were maintained on nude mice by serial transplantation. The established tumor cell lines were used to determine the assay evaluability of three different drug-testing systems: the subrenal capsule assay (SRC), the in vitro assay with labeled DNA precursor (L-DNA-P) and the stem cell assay (STC). Tumor cell lines were used because they allowed us to perform the different assays with the same tumor. Criteria for assay evaluability were measurable growth of the transplanted tumor fragment (histologically proved) in the SRC-assay, the amount of thymidine incorporation in relation to the number of cells in vitro and time of incubation in the L-DNA-P-assay, and a mean colony count for the sixfold plated cells of 50 or greater in the STC-assay. The criteria for evaluability were fulfilled when athymic or irradiated immunocompetent mice were used for the SRC-assay. However, in immunocompetent, non-irradiated mice, remarkable incursion of host cells was found. In the L-DNA-P-assay, optimal incorporation was reached after different times of culture, with different cell numbers. Therefore the technique of assaying with labeled DNA precursor lacks optimally defined assay conditions. The tumor cell lines examined in the stem cell assay demonstrated excellent growth; they therefore may be useful for pharmacological studies of drug interactions.