Abrogation of the requirements for added growth factors in 3T3 cells constitutively expressing the p53 and IGF-1 genes.
Two constructs (co-transfected with selectable markers) were used to establish cell lines from BALB/c3T3 cells: a p53 mini-gene under the control of an LTR promoter and a synthetic IGF-1 coding sequence driven by the SV40 early promoter. BALB/c3T3 cells do not grow in plasma or in 1% serum or in soft agar and in defined media require both platelet-derived growth factor (PDGF) and insulin (or IGF-1). Cells carrying only the LTR/p53 mini-gene grew well in plasma (but not in 1% serum), in soft agar and in serum-free medium containing only insulin. Cells carrying only the SV40/IGF-1 gene grew (but not too vigorously) in soft agar and grew well in serum-free medium containing PDGF but no insulin. Cells carrying both constructs grew very well in plasma, in soft agar and in serum-free medium without PDGF nor insulin. The results indicate that the requirements for growth of BALB/c3T3 cells can be reduced to two genes: IGF-1 and a gene replacing PDGF (p53 in our case). An unexpected, but interesting observation was that cells carrying the LTR/p53 gene grew slower in 10% serum than in plasma.
Gai
X X
XX
Department of Pathology, Temple University Medical School, Philadelphia, Pennsylvania 19140.
Rizzo
M G
MG
Lee
J
J
Ullrich
A
A
Baserga
R
R
D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002455:Cell Division; D002460:Cell Line; D003470:Culture Media; D005786:Gene Expression Regulation; D006133:Growth Substances / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D051379:Mice; D009363:Neoplasm Proteins / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology*; D013002:Somatomedins / Q000502:physiology*; D014162:Transfection; D016159:Tumor Suppressor Protein p53
D003470:Culture Media; D006133:Growth Substances; D007328:Insulin; D009363:Neoplasm Proteins; D010750:Phosphoproteins; D013002:Somatomedins; D016159:Tumor Suppressor Protein p53; D007334:Insulin-Like Growth Factor I