细胞外信号调节激酶1/2在瘦素促进子宫内膜癌Ishikawa细胞增殖中的作用

The Role of ERK1/2 in Leptin Promoting the Proliferation of Human Endometrial Cancer Cell Line Ishikawa

背景与目的:流行病学研究提示瘦素与子宫内膜癌的发生有关,但其作用机制尚不清楚。瘦素作为促有丝分裂原,能够显著促进多种细胞的生长增殖。本研究的目的在于探讨细胞外信号调节激酶1/2(extracellular signal-regulated kinase1/2,ERK1/2)在瘦素促进子宫内膜癌细胞增殖中的作用。方法:免疫荧光染色检测Ishikawa细胞中瘦素受体的表达;于Ishikawa细胞中分别加入不同浓度的瘦素(0、10、50、100、150ng/ml),作用不同时间(6、12、24h),MTT法检测各组细胞的增殖情况;同时应用ERK1/2激酶特异性抑制剂PD98059阻断ERK1/2磷酸化,观察其对瘦素促进Ishikawa细胞增殖的影响;应用免疫印迹技术检测100ng/ml瘦素作用于Ishikawa细胞不同时间后(20、40、60min)ERK1/2的活化水平(以p-ERK1/2与ERK1/2的比值表示)。结果:免疫荧光检测结果证实Ishikawa细胞存在瘦素受体的表达;瘦素能明显促进Ishikawa细胞的增殖,在0～100ng/ml范围内瘦素浓度越高,细胞增殖越显著,100ng/ml瘦素作用24h其增殖效应最大(A值=0.73±0.02),100ng/ml组与150ng/ml组差异无统计学意义(P=0.129);PD98059能明显抑制瘦素对Ishikawa细胞的增殖作用,100ng/ml瘦素和100μmol/LPD98059作用24h后,细胞增殖率为(6.88±0.86)%;Ishikawa细胞经100ng/ml瘦素处理后,ERK1/2活化程度明显增高。结论:瘦素可能通过激活ERK1/2信号转导途径促进子宫内膜癌细胞的增殖。

BACKGROUND ＆ OBJECTIVE： Epidemiologic studies showed that leptin is closely related to the tumorigenesis of endometrial cancer, but the mechanism is unclear. As a mitogenic agent, leptin can promote the proliferation of many kinds of cells. This study was to explore the role of extracellular signal-regulated kinase 1/2 （ERK1/2） in leptin promoting the proliferation of human endometrial cancer cell line Ishikawa. METHODS： The expression of leptin receptor OB-Rb in Ishikawa cells was detected by fluoroimmunoassay. Ishikawa cells were treated by leptin at various concentrations （0, 10, 50, 100, and 150 ng/ml） for different time （6, 12, and 24 h）. Cell proliferation was examined by M-IF assay. Meanwhile, the effect of PD98059, selective inhibitor of ERK1/2, on the proliferation of Ishikawa cells induced by leptin was also studied. Ishikawa cells were treated with 100 ng/ml leptin for different time （20, 40, and 60 min）, then the levels of phosphorylated ERK1/2 （p-ERK1/2） and ERK1/2 were examined by Western blot. RESULTS： Fluoroimmunoassay showed the presence of OB-Rb in Ishikawa cells. Leptin stimulated the proliferation of Ishikawa cells. This effect was maximal at 100 ng/ml after 24-hour treatment, and there was no significant difference between 100 ng/ml group and 150 ng/ml group （P= 0.129）. Blocking ERK1/2 phosphorylation by PD98059 significantly reduced the proliferation of Ishikawa cells stimulated by leptin. When treaded with 100 ng/ml Leptin and 100 μmol/L PD98059 for 24 h, cell proliferation rate was （6.88±0.86）%. ERK1/2 phosphorylation was enhanced significantly in Ishikawa cells after treatment of 100 ng/ml leptin. CONCLUSION： Leptin may promote the proliferation of endometrial cancer Ishikawa cells by activating ERK1/2 signaling pathway.