Related Experiment Videos
Differential EGF action on nuclear protooncogenes in human endometrial carcinoma RL95-2 cells
M Sallot1, C Ordener, I Lascombe
1Service de Biochimie-Biologie, Moléculaire, Institut d'Etude et de Transfert de Gènes, Besancon, France.
Abstract:
Our aim was to analyze EGF action on nuclear protooncogenes in RL95-2 since it has not been documented so far. Synchronization and partial' growth arrest were obtained by maintaining cells for 15 hours in L-methionine-free medium. After this depletion, EGF transiently increased fos and jun mRNAs: the expression peaked at 45 minutes for c-fos (5.5 fold induction) and at 60 minutes for c-jun and jun-B (3 fold induction) and the mRNA levels returned to the basal value within 3 hours. Upon EGF addition, c-myc mRNAs peaked at 12 hours (7.6 fold induction) and surprisingly remained higher than the control up to 48 hours. Unlike fetal calf serum, EGF did not increase the cell number and this could be linked to steadily induced c-myc expression. These data provide evidence for a differential EGF action on fos/jun and c-myc in RL95-2 cells.
Insights
Epidermal growth factor (EGF) differentially affects protooncogene expression in RL95-2 cells. EGF transiently induces fos/jun mRNA but persistently elevates c-myc mRNA, impacting cell growth.
Area of Science:
- Cell Biology
- Molecular Biology
- Oncology
Background:
- Protooncogenes play critical roles in cell growth and differentiation.
- Epidermal Growth Factor (EGF) is a key signaling molecule involved in various cellular processes.
- The specific effects of EGF on nuclear protooncogenes in RL95-2 cells remain largely uncharacterized.
Purpose of the Study:
- To investigate the action of EGF on nuclear protooncogene expression in RL95-2 cells.
- To elucidate the differential regulation of fos/jun and c-myc genes by EGF.
- To correlate protooncogene expression changes with cellular responses like cell proliferation.
Main Methods:
- RL95-2 cells were synchronized and subjected to partial growth arrest using L-methionine-free medium.
- Cells were treated with EGF, and the expression levels of c-fos, c-jun, jun-B, and c-myc mRNAs were analyzed over time using quantitative methods.
- Cell number was assessed to evaluate the proliferative response to EGF compared to fetal calf serum.
Main Results:
- EGF treatment led to a transient increase in c-fos, c-jun, and jun-B mRNA levels, peaking within 1-2 hours and returning to basal levels within 3 hours.
- EGF induced a significant and sustained elevation of c-myc mRNA, which remained elevated for up to 48 hours post-treatment.
- Unlike fetal calf serum, EGF did not stimulate an increase in RL95-2 cell number, potentially linked to the persistent c-myc induction.
Conclusions:
- EGF exhibits differential regulation of immediate-early response genes (fos/jun) and the c-myc protooncogene in RL95-2 cells.
- The sustained induction of c-myc by EGF may play a role in its lack of proliferative effect on these cells.
- These findings highlight a complex signaling pathway involving EGF, protooncogenes, and cell cycle regulation in RL95-2 cells.