Abstract.
Background: 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.
Methods: 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.
Results: 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 IC50 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 IC50 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.
Conclusion: Overexpression of MGr1-Ag is associated with the MDR phenotype of gastric cancer cells.
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Received: January 15, 2002 / Accepted: May 9, 2002
Acknowledgments This work was supported by the National Natural Science Foundation of China (no. 30030140 and no. 39880007) and the State Basic Research Project of China (no. G1998051203). We thank Dr. Fanrong Meng for her assistance in the preparation of this manuscript.
Offprint requests to: D. Fan
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Shi, Y., Han, Y., Wang, X. et al. MGr1-Ag is associated with multidrug-resistant phenotype of gastric cancer cells. Gastric Cancer 5, 0154–0159 (2002). https://doi.org/10.1007/s101200200027
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DOI: https://doi.org/10.1007/s101200200027