A major goal of this project is to detect and clone a transforming gene from the human prostatic cancer cell line, PC-3. Transforming activity has been found in PC-3 genomic DNA by the NIH/3T3 cells focus assay. Using the nude mouse tumorigenicity assay in conjunction with drug selection of NIH/3T3 contransfected cells, the presence of an activated oncogene was confirmed. This unidentified oncogene, which does not appear to be a member of the ras family, is being cloned by sib selection using human repeated sequences as a probe. Preliminary results suggest the possible presence of suppressor DNA sequences that inhibit tumorigenicity of certain NIH/3T3 cells. Isolation of this suppressor activity also has been undertaken by sib selection. Autocrine activities of PC-3 and its highly metastatic variants are being investigated in collaboration with D. Sirbasku (university of Texas). An ascites line (PC-3asc) was isolated directly in serum-free medium from a tumor obtained by inoculation of PC-3/mA2 in the nude mouse (in collaboration with J. Kozlowski). The PS-3asc line was found to produce an autogenous factor that stimulated its own growth at low cellular inocula. In addition, preliminary data indicate that medium conditioned by PC-3asc cells has TGF activity in normal rat kidney (NRK) cells in soft agarose. This putative TGF is being isolated and will be further purified by standard biochemical procedures. Karyotypic analysis has shown that the PC-3asc line has many features in common with the parental line, PC-3/mA2, except for a few marker chromosomes with homogeneously staining region and numerous minute and double minute chromosomes.
