Possible requirement of serum progression factors for transformation of BALB/c 3T3 fibroblasts by v-ras p21.
To form colonies in soft agar, ras-transformed 3T3 fibroblasts require serum. We examined what growth factors in serum were essential for ras-induced transformation. Temperature-sensitive (ts) v-Ki-ras-transfected BALB/c 3T3 cells were used to strictly control both the activity of the ras protein and the cell cycle. When G0-arrested ts cells were cultured with 10% serum at a permissive temperature, greater than 50% of cells formed colonies. A similar colony-forming activity was observed in the presence of 10% platelet-poor plasma, but not in the presence of 10% plasma isolated from hypophysectomized rats. Inhibitors of IGF signals attenuated colony formation in the presence of serum. These data suggest that progression factors, probably IGFs, are essential components in serum for ras-induced transformation of 3T3 fibroblasts.
Harada
S
S
Fourth Department of Internal Medicine, University of Tokyo School of Medicine, Japan.
Nishimoto
I
I
D016475:3T3 Cells; D000818:Animals; D001769:Blood; D002453:Cell Cycle / Q000187:drug effects; D002471:Cell Transformation, Neoplastic; D003035:Cobalt / Q000494:pharmacology; D003470:Culture Media; D011905:Genes, ras; D007016:Hypophysectomy; D007306:Insecticides / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D009568:Nitrendipine / Q000494:pharmacology; D015689:Oncogene Protein p21(ras) / Q000235:genetics*; D011722:Pyrethrins / Q000494:pharmacology; D051381:Rats; D016192:Resting Phase, Cell Cycle; D013696:Temperature; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D003470:Culture Media; D007306:Insecticides; D011722:Pyrethrins; D010566:Virulence Factors, Bordetella; D003035:Cobalt; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D009568:Nitrendipine; D015689:Oncogene Protein p21(ras); C009424:tetramethrin