title: Infection by Cx43 adenovirus increased chemotherapy sensitivity in human gastric cancer BGC-823 cells: not involving in induction of cell apoptosis.
abstract: OBJECTIVE
  There is a lower basal expression of Connexin43 (Cx43) in human gastric cancer BGC-823 cells. In the present study, BGC-823 cells were transfected with recombinant Cx43 adenovirus plasmid vector, and we explored the influences of Cx43 expression on cell proliferation, chemo-sensitivity, colony forming ability, invasion ability and apoptosis. Moreover, we also determined the expression of Pgp, Cx43, as well as apoptosis-related proteins (bcl-2, bax, caspase3 and caspase 9).
  
  
  METHODS
  MTT assay was performed to determine the proliferation of BGC-823 cells before and after Cx43 transfection. The influences of Cx43 infection on sensitivity of chemotherapy (including Doxorubicin, fluorouracil, oxaliplatin) were detected by MTT assay. Expression levels of Pgp, Cx43, as well as apoptosis-related proteins (bcl-2, bax, caspase-3 and caspase-9) in BGC-823 cells were determined by Western blotting analysis before and after the infection with Cx43 adenovirus. MDR expression was determined by RT-PCR before and after Cx43 infection. Invasive ability was detected by invasion chamber. Influence of Cx43 adenovirus infection on apoptosis of BGC-823 cells was determined by flow cytometry.
  
  
  RESULTS
  After infection by Cx43 adenovirus, colony forming rate and invasive ability of BGC-823 cells were decreased. Flow cytometry results revealed that cell apoptosis were insignificantly increased. The data of MTT assay revealed that infection with Cx43 adenovirus, cell proliferation ability decreased and sensitivity to chemotherapy drugs (including doxorubicin, fluorouracil, oxaliplatin) increased. Results of Western blotting analysis revealed that increasing expression levels of Cx43, decreasing expression levels of Pgp, and insignificant changes of bcl-2, bax, caspase3 and caspase 9 were detected. RT-PCR revealed the expression of MDR1 gene, the gene encoding Pgp, decreased significantly (p<0.05).
  
  
  CONCLUSIONS
  The human gastric cancer BGC-823 cells were infected with Cx43-IRES2-EGFP recombinant adenovirus vector. Colony formation, invasive ability and cell proliferation all decreased, whereas chemo-sensitivity increased in Cx43 infected BGC-823 cells. The increasing Cx43 expression was accompanied by decreasing Pgp expression and MDR1 m RNA levels. However, apoptosis-related proteins (bcl-2, bax, caspase3 and caspase 9) and cell apoptosis increased insignificantly. All results demonstrated that Cx43 may be negatively regulated the development, invasion and metastasis of gastric cancers, however, it had no obvious relationship with tumor cell apoptosis.
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Dan
authors: D
authors: Liu
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Hongfeng
authors: H
authors: Zhou
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China. Electronic address: wujintree@163.com.
authors: Jin
authors: J
authors: Wu
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Wentao
authors: W
authors: Liu
authors: Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
authors: Yongqing
authors: Y
authors: Li
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Guangyue
authors: G
authors: Shi
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Xiaolong
authors: X
authors: Yue
authors: Harbin Medical University cancer Institute, Harbin, 150081, China.
authors: Xiwen
authors: X
authors: Sun
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Yanbin
authors: Y
authors: Zhao
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Xiaowei
authors: X
authors: Hu
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Tianjiao
authors: T
authors: Wang
authors: The Seventh Department of the Internal Medicine, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, 150081, China.
authors: Xufeng
authors: X
authors: Zhang
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D000256:Adenoviridae; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects / Q000235:genetics; D018031:Connexin 43 / Q000235:genetics*; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005472:Fluorouracil / Q000494:pharmacology; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D009944:Organoplatinum Compounds / Q000494:pharmacology; D000077150:Oxaliplatin; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D014162:Transfection
chemical_list: D018031:Connexin 43; C500216:GJA1 protein, human; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D004317:Doxorubicin; D005472:Fluorouracil
keywords: Cell apoptosis; Chemotherapy drug resistance; Cx43; Invasion