CHARACTERIZATION OF ADULT HUMAN PROSTATIC EPITHELIAL-CELLS IMMORTALIZED BY POLYBRENE-INDUCED DNA TRANSFECTION WITH A PLASMID CONTAINING AN ORIGIN-DEFECTIVE SV40-GENOME

Normal adult human prostatic epithelial cells were infected with an ad enovirus 12-SV40 virus or transfected by polybrene-induced gene transf er with a plasmid (pRSV-T) containing the SV40 early region genes or w ith a plasmid (pRNS-1) containing an origin-defective SV40 genome and a plasmid carrying the neomycin resistance gene. Colonies of morpholog ically altered cells were isolated, cultured in a serum-free medium an d characterized. These cells had extended lifespan in culture compared to normal adult human prostatic epithelial cells. Both Ad12-SV40-infe cted and pRSV-T-transfected cultures eventually underwent senescence. pRNS-1-transfected cells (pRNS-1-1), however, have now been grown for more than 50 passages. These cells contain the SV40 genome, express SV 40 T-antigen, and are not tumorigenic in nude mice. They express cytok eratins 5 and 8, like the parent cells, and are pseudodiploid. Analysi s of growth regulatory processes revealed that the growth of pRNS-1-1 cells was stimulated similarly to that of normal prostatic epithelial cells by epidermal growth factor, insulin-like growth factor, and pitu itary extract. The response of pRNS-1 cells to a growth-inhibitory fac tor, retinoic acid, was also similar to that of normal cells. However, pRNS-1-1 cells were less responsive than normal cells to growth inhib ition by transforming growth factor-beta, and had lost altogether the ability of normal cells to be inhibited by tumor necrosis factor-alpha and 1,25 (OH)2 vitamin D3. Therefore transformation appeared to alter growth-inhibitory but not growth - stimulatory mechanisms. These cell s should be useful in elucidating the multistep mechanism of carcinoge nesis of the prostate.