促性腺激素释放激素拮抗剂在诱导HEC-1A子宫内膜癌细胞株生长抑制中MAPK的活性

Activation of mitogen-activated protein kinase in growth inhibition of human endometrial cancer cells line induced by gonadotropin-releasing hormone antagonist Cetrorelix

目的调查促性腺激素释放激素(GnRH)拮抗剂Cetrorelix对HEC-1A子宫内膜癌细胞株生长是否具有直接抑制作用,并探讨它的作用机制。方法应用RT-PCR法测定在子宫内膜癌细胞株促性腺激素释放激素及它的受体mRNA的表达。应用5-溴-2'-脱氧尿嘧啶核苷(5-bromo-2'-deoxyuridine,BrdU)免疫组化标记技术测定细胞增殖变化。应用Western免疫印迹技术测定与信号传导相关的丝裂原活化蛋白激酶/MAPK的蛋白水平。结果 HEC-1A细胞株表达GnRH及其受体。GnRH拮抗剂Cetrorelix在浓度10^(-5)mol/L下,体外作用24h后抑制了HEC-1A细胞的生长。Cetrorelix在浓度10^(-6)mol/L与10^(-5)mol/L之间作用于HEC-1A细胞6h,磷酸化丝裂原活化蛋白激酶/ERK1/2蛋白水平增长,并持续24h,这个增长被提前加入丝裂原或化蛋白激酶/MEK抑制剂U0126而阻止。而磷酸化p38、JNK蛋白水平没有变化。结论结果表明持续的ERK1/2活性在Cetrorelix抑制HEC-1A细胞生长中发挥重要作用。

Objective The expression of gonadotropin-releasing hormone（GnRH） and its receptor has been demonstrated in peripheral tissues as well CNS.Although antineoplastic activity of GnRH antagonist has been demonstrated,the mechanism of action of these peptide analogs remains incompleted understand.The objectives of this study were to investigate direct antiproliferative effect of GnRH antagonist Cetrorelix on HEC-1A human endometrial cancer cell line and elucidate its underlying mechanism.Methods RT-PCR was performed to detect mRNA expression for GnRH and its receptor in HEC-1A cells.The proliferation of HEC-1A cells was examined by measuring incorporation of 5-Bromo-2′-deoxyuridine （BrdU） into DNA.Signal transduction-related mitogen activated-protein kinase （MAPK） protein levels were evaluated by Western Blot.Results HEC-1A cells expressed mRNA for GnRH and GnRH receptor.Cetrorelix,at 10～（-5） mol/L,exerted an antiproliferative action on HEC-1A cells.Cetrorelix,at concentrations between 10～（-6） and 10～（-5） mol/L（24 h）,extracellular signal-regulated kinase 1/2 （ERK1/2） protein level exerted a dose-dependent increased on HEC-1A cells and at the concentration of 10-5 mol/L ERK1/2 protein level exerted the largest increased after 24 h treatment and canceled by U0126,an inhibitor of mitogen-activated protein/MEK kinase （MAPK/MEK）.While the protein levels of activated c-JUN N-terminal kinase （JNK） and p38 kinase were not to change significantly.Conclusions These results demonstrate that the successive activation of ERK1/2 might play an important role in the antiproliferation effects of Cetrorelix on HEC-1A cell lines.