Effects of various chemical agents on the transformation of rat fibroblasts by an activated c-Ha-ras oncogene

✍ Scribed by Cecilia A. Lopez; W.-L. Wendy Hsiao; I. Bernard Weinstein

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 563 KB
• Volume: 2
• Category: Article
• ISSN: 0899-1987
• DOI: 10.1002/mc.2940020206

✦ Synopsis

We have previously reported that the potent tumor-promoting agent 12-0-tetradecanoylphorbol-13-acetate (TPA) and a factor from fetal calf serum (FCS) markedly enhance the transformation o f mouse C3H 10T1/2 and Rat 6 fibroblasts, when added t o cultures following transfection with plasmid pT24 DNA that contains an activated c-Ha-ras oncogene. In the present study, we examined possible enhancing or inhibiting effects o f various chemicals on the transformation o f Rat 6 fibroblasts by T24 DNA when tested in the presence of calf serum, calf serum plus TPA or FCS. We found that, like TPA, the chemicals mezerein, l-oleoyl-2-acetylglycerol, and phospholipase C increased the yield of T24-induced foci, thus further implicating protein kinase C as a critical constituent in this process. Low concentrations (10-6-10-7 M) of retinoicacid (both transand 13-cis) also stimulated cell transformation. Several compounds inhibited T24-induced transformation. These included nontoxic concentrations of the calcium ionophore A23187, indomethacin, and €-amino-n-caproic acid. Compounds that failed t o exert a significant reproducible effect included vasopressin, vitamin D3, selenium, antipain, Bowman-Birk inhibitor, vitamin BIZ, epidermal growth factor, platelet-derived growth factor, insulin, and transferrin. These findings suggest that this simple in vitro system might be useful for detecting enhancers and inhibitors o f ras oncogene-induced cell transformation and also elucidating their mechanisms o f action.