Original Articles
Copyright ©The Author(s) 1998. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 15, 1998; 4(5): 421-425
Published online Oct 15, 1998. doi: 10.3748/wjg.v4.i5.421
Transduction of Fas gene or Bcl-2 antisense RNA sensitizes cultured drug resistant gastric cancer cells to chemotherapeutic drugs
Bing Xiao, Yong-Quan Shi, Yan-Qiu Zhao, Han You, Zuo-You Wang, Xian-Ling Liu, Fang Yin, Tai-Dong Qiao, Dai-Ming Fan
Bing Xiao, Yong-Quan Shi, Yan-Qiu Zhao, Han You, Zuo-You Wang, Xian-Ling Liu, Fang Yin, Tai-Dong Qiao, Dai-Ming Fan, Department of Gastroenterology, Xijing Hospital, the Fourth Military Medical University, Xi’an 710032, Shaanxi Province, China
Bing Xiao, born on 1962-09-12 in Fujian of China, He received a bachelor degree from Fujian Medical College in 1984, and received MD degree from the First Military Medical University in 1996. Engaged in gene therapy and gene cloning.
Author contributions: All authors contributed equally to the work.
Correspondence to: Bing Xiao, Institute of Gastroenterology, Xijing Hospital, the Fourth Military Medical University, No.17 Changle Xilu, Xi’an 710032, Shaanxi Province, China
Telephone: +86-29-3221616-72863
Received: August 6, 1998
Revised: September 22, 1998
Accepted: September 30, 1998
Published online: October 15, 1998
Abstract

AIM: To compare the expression level of Fas gene and Bcl-2 gene in gastric cancer cells SGC7901 and gastric cancer multidrug resistant cells (MDR) SGC7901/VCR, to transduce Fas cDNA and Bcl-2 antisense nucleic acid into SGC7901/VCR cells respectively, and to observe the expression of two genes in transfectants and non-transfectants as well as their drug sensitivity.

METHODS: Eukaryotic expression vector pBK-Fas cDNA and pDOR-anti Bcl-2 were constructed and transfected into SGC7901/VCR cells by lipofectamine,respectively. Northern blot and Western blot were used to detect the expression of mRNA and protein in SGC7901/VCR and SGC7901 cells and transfectants, and drug sensitivity of transfectants for VCR, CDDP and 5-FU was analyzed with MTT assay.

RESULTS: After gene transfection, 80 for Fas and 120 for antisense Bcl-2 drug-resistant clones were selected from 2 × 105 cells, transfection rate being 0.04% and 0.06%. Two clones of SGC7901 Fas/VCR cells and SGC7901 anti Bcl-2/VCR cells were randomly selected for further incubation. Hybridization results showed that the expression level of Fas mRNA and protein in SGC7901/VCR cells was much lower, but that of Bcl-2 mRNA and protein was higher than that in SGC7901 cells. The expression of Fas mRNA and protein in SGC7901 Fas/VCR cells was higher, and of Bcl-2 mRNA and protein was lower in SGC7901 anti Bcl-2/VCR cells than that in non-transfectants. MTT assay showed that transfectants were more sensitive to VCR, CDDP, 5-FU than non-transfectants.

CONCLUSION: Bcl-2 gene displayed high expression while Fas gene had low expression in drug resistant gastric cancer cells. Expression of Bcl-2 protein was effectively blocked in SGC7901 anti Bcl-2/VCR cells by gene transfection. In contrast, the expression of Fas mRNA and protein in SGC7901 Fas/VCR cells increased. Fas gene and Bcl-2 antisense nucleic acid transfection sensitized drug resistant gastric cancer cells to chemotherapeutic drugs. These results suggest cell apoptosis plays an important role in the mechanism of MDR, and enhancing apoptosis might reverse MDR.

Keywords: stomach neoplasms; Fas gene; Bcl-2 gene; antisense nucleic acid; drug resistance, multiple; gene transduction; apoptosis