Glucocorticoid dexamethasone reversibly complements EJ-RAS oncogene to transform mouse embryo BALB-3T3 cells.
EJ-A is a Balb-3T3 transfectant cell line that bears a small number of EJ-ras oncogene copies/cell, has low EJ-ras expression, and resembles the parental cell line in displaying a non-transformed phenotype. The glucocorticoid hormone dexamethasone reversibly induces transformation traits in EJ-A cells, namely: 1) morphological transformation; 2) increased growth rate and saturation density; 3) reduced G1 length; and 4) independence of the FGF requirement to initiate DNA synthesis. Western blot analysis revealed that dexamethasone does not increase the p21ras protein intracellular level. beta-IFN, added to the culture medium, does not suppress the dexamethasone-induced growth stimulation and morphological transformation. Therefore, glucocorticoid hormones can complement low EJ-ras expression to transform Balb-3T3 cells, by a mechanism that is likely to be independent of p21ras increase and beta-IFN decrease.
Kovary
K
K
Departamento de Bioquímica, Instituto de Química Universidade de São Paulo, Brasil.
Armelin
M C
MC
Armelin
H A
HA
D000818:Animals; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic; D003043:Cocarcinogenesis; D004247:DNA / Q000096:biosynthesis; D003907:Dexamethasone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D011905:Genes, ras / Q000502:physiology*; D007328:Insulin / Q000494:pharmacology; D007370:Interferon Type I / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D015689:Oncogene Protein p21(ras) / Q000032:analysis; D014162:Transfection; D014170:Transformation, Genetic / Q000187:drug effects*
D007328:Insulin; D007370:Interferon Type I; D005346:Fibroblast Growth Factors; D004815:Epidermal Growth Factor; D003907:Dexamethasone; D004247:DNA; D015689:Oncogene Protein p21(ras)