Objective To study the expression and clinical significance of Notch3 and Notch intracellular domain (NICD) in ovarian carcinoma and the effects of N-[N-(3 ,5-difluorophenyl) acetyl-L-alanyl]-S-phenyl glycine t-butyl ester (DAPT), a γ-secretase inhibitor on the proliferation and apoptosis in OVCAR3, A2780 ovarian carcinoma cell lines. Methods Western blot was used to detect the expression of NICD in the tissues from 58 ovarian carcinomas patients and 21 normal ovarie, who were admitted in Peking University First Hospital from July 2006 to June 2009. Immunohistochemistry was also used to detect the expression of Notch3 in these tissues. The relationship with clinical features of ovarian carcinoma was also analyzed. Proliferation of OVCAR3 and A2780 ovarian cancer cells was determined by methyl thiazolyl tetrazolium (MTT) assay, cell cycles and apoptosis and index of proliferation were detected by flow cytometry method. The expression of NICD in OVCAR3 and A2780 cells incubated with DAPT was detected by western blot. Results (1)The expression level of NICD in ovarian carcinomas was significantly higher than that in normal ovarian tissues (1.64 ±0. 19 vs. 0.98 ±0.20;P <0.05). The NICD expression was higher in ovarian cancers with low grade or advanced stage than those in high-middle grade or early stage,respectively (1.90 ± 0. 22 vs. 1.25 ± 0. 21,1.80 ± 0. 21 vs. 1.21 ± 0. 15; all P < 0. 05). The Notch3 protein was stained positively in cytoplasm, nuclear and cell membrane. The expression of Notch3 was higher in ovarian carcinomas than that in normal ovaries [78% (45/58) vs. 24% (5/21); P < 0. 01]. While,there were no stasistical difference in different pathological types, stages, differentiation of ovarian carcinoma. There was no difference between the patients with adjuvant chemotherapy or not. (2)After OVCAR3 and A2780 cells incubated with DAPT 24, 48, 72 hours, NICD expression was significantly lower than that in control group (P < 0. 05). The effects of DAPT inhibited the proliferation and prompted the apoptosis of OVCAR3 and A2780 cells were depended on the concentrations and times. Conclusions Notch3 and NICD may play a key role in the occurrence and progress of ovarian carcinoma. The mechanism of DAPT inhibited the proliferation and prompted the apoptosis of OVCAR3 and A2780 cells may be due to decreased the formation of NICD.%目的 了解卵巢上皮性癌(卵巢癌)组织中Notch3及Notch基因细胞内区(NICD)蛋白的表达水平及其临床意义,探讨γ分泌酶抑制剂--氮-[氮-(3,5-二氟苯乙酰基)-L-丙氨酰]-S-苯基甘氨酸丁酯(DAPT)对卵巢癌细胞系OVCAR3、A2780细胞的作用.方法 (1)选取2006年7月到2009年6月在北京大学第一医院因卵巢癌接受手术治疗且临床病理资料完整的患者共58例,选取同期因子宫肌瘤或子宫腺肌病及其他非卵巢病变行子宫全切除+双侧附件切除术者共21例作为对照,采用蛋白印迹法检测卵巢癌及正常卵巢组织中NICD蛋白的表达水平,免疫组化法检测卵巢癌及正常卵巢组织中Notch3蛋白的阳性表达率,并对不同临床病理特征的卵巢癌组织中NICD和Notch3蛋白表达进行比较.(2)体外培养卵巢癌OVCAR3、A2780细胞,加入不同浓度(分别为0.1、1、5、10μmol/L)的DAPT,设仅加溶剂二甲基亚砜(DMSO)者为空白对照,采用蛋白印迹法检测DAPT处理后卵巢癌OVCAR3、A2780细胞中NICD蛋白表达水平的变化,四甲基偶氮唑蓝(MTT)比色法检测卵巢癌细胞的生长情况,流式细胞仪检测细胞增殖指数(PI)、S期细胞比例(SPF)和细胞凋亡率的变化.结果 (1)卵巢癌、正常卵巢组织中Notch3蛋白的阳性表达率分别为78%(45/58)、24%(5/21),两者比较,差异有统计学意义(P<0.01).卵巢癌、正常卵巢组织中NICD蛋白的表达水平分别为1.64±0.19、0.98±0.20,两者比较,差异有统计学意义(P<0.05).卵巢癌组织中,NICD蛋白的表达水平,病理分化程度为低分化者(1.90±0.22)明显高于高～中分化者(1.25±0.21,P<0.05),手术病理分期为Ⅲ～Ⅳ期者(1.80±0.21)明显高于Ⅰ期者(1.21±0.15,P<0.05),而不同病理类型和是否行新辅助化疗间比较,差异则无统计学意义(P>0.05);Notch3蛋白的阳性表达率,不同病理类型、手术病理分期、病理分化程度及是否行新辅助化疗间比较,差异均无统计学意义(P>0.05).(2)DAPT(5 μmol/L)处理不同时间(分别为24、48、72 h)后,OVCAR3、A2780细胞中NICD蛋白的表达水平均明显低于空白对照(P<0.05).不同浓度(分别为0.1、1、5、10 μmol/L)的DAPT处理不同时间(分别为0、6、12、24、36、48、72 h)后,OVCAR3、A2780细胞的生长均明显受抑制,分别与空白对照比较,差异均有统计学意义(P<0.05).不同浓度(分别为0.1、1、5、10 μmol/L)的DAPT处理不同时间(分别为24、48、72 h)后,OVCAR3、A2780细胞的SPF、PI明显下降,细胞凋亡率明显升高,分别与空白对照比较,差异均有统计学意义(P<0.05),且随着药物浓度的升高,出现这种作用的时间越早.结论 Notch3、NICD蛋白可能在卵巢癌的发生、发展中起一定的促进作用;DAPT能抑制卵巢癌细胞的增殖,促进卵巢癌细胞的凋亡,其机制可能与抑制NICD蛋白的生成有关.
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