Effect of dexamethasone and cycloheximide on the expression of amplified EGF-receptor gene in human A431 carcinoma cell line.
Human A431 carcinoma cell line is known to have 30 fold amplified epidermal growth factor receptor (EGF-R) gene. We have studied the effect of steroid hormone dexamethasone (DEX) and protein synthesis inhibitor cycloheximide (CHX) on the expression of EGF-R gene in this cell line. DEX treatment and protein synthesis inhibition by CHX treatment cause a rapid 3 to 4 fold increase in the level of EGF-R mRNA and combined treatment of the above two agents have less than additive effect. It appears that mRNA for EGF-R accumulate within the cell during protein synthesis inhibition and upon removal of CHX, gets translated into EGF-R specific protein as judged by immuno-dot assay. We did not observe the phenomenon of 'super induction' nor much of an additive effect under condition of combined DEX and CHX treatment.
Gope
M L
ML
Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.
Gope
R
R
Zarucki
T
T
D001345:Autoradiography; D015152:Blotting, Northern; D002294:Carcinoma, Squamous Cell; D003513:Cycloheximide / Q000494:pharmacology*; D003907:Dexamethasone / Q000494:pharmacology*; D004347:Drug Interactions; D066246:ErbB Receptors / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D015151:Immunoblotting; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D003907:Dexamethasone; D003513:Cycloheximide; D066246:ErbB Receptors