Effect of Chinese gentian on the proliferation of, apoptosis and phosphorylation of epidermal growth factor receptor in HaCaT cells

Abstract

Objective To evaluate the effect of Chinese gentian extracts on the proliferation of,apoptosis and phosphorylation of epidermal growth factor receptor (EGFR) in HaCaT cells induced by epidermal growth factor (EGF).Methods Methyl thiazolyl tetrazolium (MTT) assay was performed to evaluate the proliferation of HaCaT cells pretreated with EGF of 20 μg/L for 24 hours followed by 24 hours of treatment with various concentrations of Chinese gentian extracts.Flow cytometry was carried out to detect apoptosis in HaCaT cells pretreated with EGF of 20 μg/L for 24 hours followed by 4 hours of treatment with different concentrations of Chinese gentian extracts.Western blot was conducted to measure the level of phosphorylated EGFR in HaCaT cells treated with different concentrations of Chinese gentian extracts for 24 hours followed by treatment with EGF of 20 μg/L for 10 minutes.Results Chinese gentian extracts inhibited the proliferation (r =-0.991,P ＜ 0.01),but promoted the apoptosis (r =0.996,P ＜ 0.05) of HaCaT cells induced by EGF in a dose-dependent manner.At the same time,the extracts suppressed the phosphorylation of EGFR in HaCaT cells induced by EGF,and the suppressing effect increased with the rise in the concentration of the extracts.Conclusions Chinese gentian may inhibit the proliferation,but promote the apoptosis of keratinocytes by decreasing EGFR phosphorylation and blocking relevant intracellular signaling pathways. Key words: Gentian; Keratinocytes; Cell proliferation; Apoptosis; Receptor, epidermal growth factor