Glucocorticoid-regulated gene in transformed to normal phenotypic reversion.
Glucocorticoid hormones modulate the actions of peptide growth factors and constitute important therapeutic tools as anti-inflammatory and anti-tumor agents. The C6 rat glioma cell line responds to glucocorticoids with changes in morphology and growth block. The hyper-responsive ST1 cell variant displays a dramatic phenotypic reversion under the influence of these hormones. Thus, the transformed and tumorigenic cells reversibly change to a normal and non-tumorigenic phenotype. In addition, the cells also produce a C-type retrovirus. We used poly A+ mRNA from ST1 cells that had been treated with hydrocortisone to generate a cDNA library that was then screened, by differential hybridization, for glucocorticoid-responsive cellular sequences. The retroviral genomic RNA was used to generate a viral-specific probe. Cross hybridization led to the isolation of at least 4 cDNA clones of which 3 are cellular sequences and one corresponds to a retroviral gene. These clones were characterized by DNA sequencing and Northern blot hybridization analysis.
Valentini
S R
SR
Departamento de Bioquímica, Universidade de São Paulo, Brasil.
Oliveira
M L
ML
Sasahara
R M
RM
Armelin
M C
MC
D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D005938:Glucocorticoids / Q000494:pharmacology*; D006133:Growth Substances / Q000502:physiology*; D010641:Phenotype; D051381:Rats; D014170:Transformation, Genetic / Q000187:drug effects*; D014407:Tumor Cells, Cultured
D005938:Glucocorticoids; D006133:Growth Substances