Shi Yongquan, Han Ying, Wang Xin, Zhao Yanqiu, Ning Xiaoxuan, Xiao Bing, Fan Daiming
Institute of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, People's Republic of China.
Gastric Cancer. 2002;5(3):154-9. doi: 10.1007/s101200200027.
MGr1-antigen (Ag) was previously reported as an upregulated protein in multidrug-resistant (MDR) gastric cancer cells. The aim of this study was to characterize the role of MGr1-Ag in the multidrug resistance of gastric cancer cells.
Laser scanning confocal microscopy (LSCM), two-dimensional electrophoresis, and Western blot were used to detect MGr1-Ag in gastric cancer cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to determine the sensitivity of the MDR gastric cancer cells, SGC7901/VCR, to chemotherapeutic drugs. Adriamycin accumulation and retention in SGC7901/VCR cells were analyzed using flow cytometry.
LSCM showed that MGr1-Ag localized mainly on the membrane and partly in the cytoplasm of SGC7901/VCR cells. Western blot showed that the expression level of MGr1-Ag in SGC7901/VCR cells was higher than that in its parental cells, SGC7901, and that the apparent molecular weight and isoelectric point of MGr1-Ag were 42 kDa and pH 4.8, respectively. After incubation with MGr1 antibody, SGC7901/VCR cells showed significantly decreased IC(50) values for adriamycin (from 0.887 +/- 0.081 mg/l to 0.607 +/- 0.084 mg/l; P, 0.05), vincristine (from 0.707 +/- 0.055 mg/l to 0.557 +/- 0.042 mg/l; P, 0.05), and 5-fluorouracil (from 4.367 +/- 0.407 mg/l to 2.630 +/- 0.644 mg/l; P, 0.05), as well as slightly increased IC(50) values for mitomycin (from 0.183 +/- 0.045 mg/l to 0.198 +/- 0.048 mg/l; P. 0.05). In addition, incubation with MGr1 significantly enhanced adriamycin accumulation and retention in SGC7901/VCR cells.
Overexpression of MGr1-Ag is associated with the MDR phenotype of gastric cancer cells.
MGr1抗原（Ag）先前被报道为多药耐药（MDR）胃癌细胞中上调的蛋白。本研究的目的是阐明MGr1-Ag在胃癌细胞多药耐药中的作用。
采用激光扫描共聚焦显微镜（LSCM）、二维电泳和蛋白质印迹法检测胃癌细胞中的MGr1-Ag。采用3-(4,5-二甲基噻唑-2)-2,5-二苯基溴化四氮唑（MTT）法测定MDR胃癌细胞SGC7901/VCR对化疗药物的敏感性。采用流式细胞术分析阿霉素在SGC7901/VCR细胞中的蓄积和滞留情况。
LSCM显示MGr1-Ag主要定位于SGC7901/VCR细胞膜上，部分位于细胞质中。蛋白质印迹法显示，SGC7901/VCR细胞中MGr1-Ag的表达水平高于其亲本细胞SGC7901，MGr1-Ag的表观分子量和等电点分别为42 kDa和pH 4.8。用MGr1抗体孵育后，SGC7901/VCR细胞对阿霉素的半数抑制浓度（IC50）值显著降低（从0.887±0.081 mg/l降至0.607±0.084 mg/l；P<0.05），长春新碱（从0.707±0.055 mg/l降至0.557±0.042 mg/l；P<0.05）和5-氟尿嘧啶（从4.367±0.407 mg/l降至2.630±0.644 mg/l；P<0.05），而丝裂霉素的IC50值略有升高（从0.183±0.045 mg/l升至0.198±0.048 mg/l；P>0.05）。此外，用MGr1孵育可显著增强阿霉素在SGC7901/VCR细胞中的蓄积和滞留。
MGr1-Ag的过表达与胃癌细胞的MDR表型相关。
