摘要：
目的 探讨肝素结合表皮生长因子(HB-EGF)通过上调核因子κB(NF-κB)的表达从而诱导卵巢上皮性癌(卵巢癌)对紫杉醇耐药的作用及可能的机制.方法(1)NF-κB表达的检测:将卵巢癌亲本细胞系A2780细胞和紫杉醇耐药细胞系A2780/Taxol细胞及其对应的裸鼠分成4组,即A2780组、A2780+交叉反应物质197(CRM197,为HB-EGF抑制剂)组、A2780/Taxol组和A2780/Taxol+CRM197组,采用双重免疫荧光染色法检测4组卵巢癌细胞中HB-EGF和表皮生长因子受体(EGFR)蛋白的表达,蛋白印迹法(western blot法)检测4组卵巢癌细胞中NF-κB的表达,免疫组化SP法检测4组裸鼠移植瘤组织中NF-κB蛋白的表达.(2)NF-κB功能的检测:将A2780/Taxol细胞分4组,即空载体组、NF-κB小分子干扰RNA(siRNA)组、空载体+CRM197组、NF-κB siRNA+CRM197组,四甲基偶氮唑蓝(MTT)比色法检测4组A2780/Taxol细胞对紫杉醇的耐药性[以50%抑制浓度(IC50)表示],western blot法检测4组A2780/Taxol细胞中P-糖蛋白(P-gp)的表达,流式细胞仪检测4组A2780/Taxol细胞中P-gp的功能[以细胞内累积的若丹明(Rh123)的荧光强度表示].结果(1)NF-κB表达的检测:A2780组、A2780+CRM197组、A2780/Taxol组和A2780/Taxol+CRM197组细胞中HB-EGF蛋白的表达水平分别为(5.6±1.3)、(2.1±1.2)、(11.7±3.5)、(6.2±1.4)分,EGFR蛋白的表达水平分别为(5.1±1.6)、(2.8± 0.6)、(10.4±3.1)、(5.6±1.9)分,NF-κB蛋白的表达水平分别为1.89±0.23、0.74±0.12、3.45±0.16、1.31± 0.08;4组裸鼠移植瘤组织中NF-κB蛋白的表达水平分别为(3.3±1.1)、(1.4±0.4)、(8.7±2.3)、(3.6±1.2)分.其中,A2780组和A2780/Taxol组细胞中HB-EGF、EGFR、NF-κB蛋白的表达水平及裸鼠移植瘤组织中NF-κB蛋白的表达水平分别高于A2780+CRM197组和A2780/Taxol+CRM197组,而A2780组细胞中HB-EGF、EGFR、NF-κB蛋白的表达水平及裸鼠移植瘤组织中NF-κB蛋白的表达水平低于A2780/Taxol组,分别比较,差异均有统计学意义(P＜0.05).(2)NF-κB功能的检测:空载体组、NF-κB siRNA组、空载体+CRM197组、NF-κB siRNA+CRM197组A2780/Taxol细胞对紫杉醇的IC50分别为(39.4± 0.8)、(7.6±0.6)、(6.7±0.5)、(4.2±0.4)μmol/L,4组A2780/Taxol细胞中P-gp蛋白的表达水平分别为3.11±0.23、1.45±0.16、1.73±0.21、0.68±0.14,4组A2780/Taxol细胞内的Rh123荧光强度分别为110±15、246±19、231±22、296±24.其中,NF-κB siRNA组、空载体+CRM197组、NF-κB siRNA+CRM197组A2780/Taxol细胞对紫杉醇的IC50及细胞中P-gp蛋白的表达水平均明显低于空载体组(P＜0.01),而细胞内Rh123荧光强度明显高于空载体组(P＜0.01);NF-κB siRNA组、空载体+CRM197组A2780/Taxol细胞对紫杉醇的IC50及细胞中P-gp蛋白的表达水平均明显高于NF-κB siRNA+CRM197组(P＜0.01),而细胞内Rh123荧光强度明显低于NF-κB siRNA+CRM197组(P＜0.01).结论 NF-κB的表达与卵巢癌紫杉醇耐药相关,HB-EGF可能通过调控EGFR/NF-κB/P-gp信号通路诱导卵巢癌对紫杉醇产生耐药.%Objective To investigate the role and mechanism of the regulation of nuclear factor-κB (NF-κB) by heparin binding-epidermal growth factor-like growth factor (HB-EGF) in paclitaxel resistance of ovarian cancer in vitro and in vivo. Methods (1) The detection of NF-κB expression: parental (A2780) and paclitaxel-resistant (A2780/Taxol) ovarian carcinoma cells were divided into four groups, named A2780 group, A2780+cross-reacting material 197 (CRM197, HB-EGF inhibitor) group, A2780/Taxol group and A2780/Taxol+CRM197 group. Among four groups, the expression level HB-EGF and epidermal growth factor receptor (EGFR) were examined by immunofluorescence double staining on confocal microscopy. Western blot was used to detect the expression level of NF-κB. In vivo, A2780 and A2780/Taxol cells were injected intraperitoneally to nude mouse to determine the expression level of NF-κB of the tumors from these four groups by immunohistochemistry method. (2) The detection on the function of NF-κB: A2780/Taxol cells were divided into four groups, named transfected with empty vector+saline group, NF-κB small interference RNA (siRNA)+saline group, empty vector+CRM197 group and NF-κB siRNA+CRM197 group respectively. Among four groups, the 50% inhibitory concentrations (IC50) of A2780/Taxol cells to paclitaxel, the expression level of plasma membrane glycoprotein (P-gp) and the effect of intracellular rhodomine123 (Rh123) accumulation were detected. Results (1) The detection of NF-κB expression: the expression scores of HB-EGF protein among four groups were 5.6±1.3, 2.1±1.2, 11.7±3.5 and 6.2±1.4; the expression scores of EGFR protein were 5.1±1.6, 2.8±0.6, 10.4±3.1 and 5.6±1.9, respectively. The expression levels of NF-κB protein in the cells of the group named A2780, A2780+CRM197, A2780/Taxol and A2780/Taxol+CRM197 group were 1.89±0.23, 0.74±0.12, 3.45±0.16 and 1.31±0.08, respectively; the expression scores of NF-κB protein in the tissue tumors from four groups were 3.3±1.1, 1.4±0.4, 8.7±2.3 and 3.6±1.2, respectively. The expression level of HB-EGF, EGFR and NF-κB protein between A2780 and A2780/Taxol groups in vivo and in vitro were higher than these in A2780+CRM197 and A2780/Taxol+CRM197 group, while the expression level of HB-EGF, EGFR and NF-κB protein in A2780 group were lower than those in A2780/Taxol groups in vivo and in vitro (P＜0.05). (2) The examination of NF-κB function: the IC50 of A2780/Taxol cells to paclitaxel in groups transfected with empty vector+saline, NF-κB siRNA+saline, empty vector+CRM197 and NF-κB siRNA+CRM197 group were respectively (39.4±0.8), (7.6±0.6), (6.7±0.5) and (4.2±0.4) μmol/L, while the expression levels of P-gp protein among four groups were respectively 3.11±0.23,1.45±0.16, 1.73± 0.21 and 0.68±0.14, the cellular Rh123 accumulation among four groups were respectively 110±15, 246±19, 231 ± 22 and 296 ± 24. The expression levels of IC50 and P-gp protein in groups transfected with NF-κB siRNA+saline, empty vector+CRM197 and NF-κB siRNA+CRM197 group were significantly higher than those in group transfected with empty vector+saline group (P<0.01), while the cellular Rh123 accumulation among three groups were significantly lower than that in group transfected with empty vector+saline (P<0.01). Conclusions The expression of NF-κB may contributes to the paclitaxel resistance to ovarian cancer. HB-EGF may induce the paclitaxel resistance of ovarian cancer by the regulation of EGFR/NF-κB/P-gp pathway.
