ABSTRACT
To investigate the relationship between the expression of early growth response gene 1(EGR-1) and p38MAPK pathway in the paclitaxel resistance of ovarian carcinoma cells, the effect of p38MAPK inhibitor SB203580 on cell apoptosis was examined by using Hoechst 33258 staining.The intracellular Rh123 (Rhodamine 123) accumulation was detected by the flow cytometry (FCM).The 50% inhibition concentration (IC50) of paclitaxel for A2780/Taxol cells was determined by MTT method. Electrophoretic motility shift assay (EMSA) was employed to examine the EGR-1DNA binding activity. MDR1 and EGR-1 mRNA were assessed by RT-PCR. The expressed of p-gp, phosphorylated p53 and p38 were detected by Western blotting. SB203580 could remarkably promote the apoptosis of A2780/Taxol cells, and the cell apoptosis was in a time-dependent manner. Cellular Rh123 accumulation was increased, and the IC50 of paclitaxel for A2780/Taxol cells was decreased significantly. A2780/Taxol cell line after SB203580 treatment was shown to have a significantly higher level of EGR-1 DNA binding activity. SB203580 down-regulated the activity of p38MAPK pathway, but up-regulated EGR-1 expression. SB203580 significantly increased the level of cellular phosphorylated p53 protein, but decreased the p-gp protein level and MDR1 mRNA level in A2780/Taxol cells. There existed a close relationship between p38MAPK pathway and the paclitaxel resistance of ovarian carcinoma cells. The expression of EGR-1 mediated by p38MAPK pathway plays a critical role in paclitaxel resistance of ovarian carcinoma cells.
ABSTRACT
The effects of Oxymatrine (Oxy) on the proliferation and apoptosis of human esophageal carcinoma Eca109 cell line and the mechanism were investigated. The human esophageal carcinoma Eca109 cells were cultured in vitro. The Oxy-induced apoptosis of Eca109 cells was assayed by using flow cytometry. The expressions of p-ERK1/2, Cyclin D1, p21waf/cip1, Bax and Bcl-2 were detected by Western blot. Flow cytometry revealed that Oxy could induce the apoptosis of Eca109 cells. Western blot showed that Oxy of different concentrations suppressed the expressions of p-ERK1/2, cyclin D1 and Bc1-2, but up-regulated the expression of p21waf/cip1 and Bax, and the ratio of Bax/Bcl-2 was increased It was suggested the Oxy could induce the apoptosis of Eca109-cells, which might be related to the upregulation of p21waf/cip1 and the downregulation of p-ERK1/2 Cyclin D1 and p21waf/cip1. The possible pathway may be related to Bcl-2/Bax.