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BAK overexpression mediates p53-independent apoptosis inducing effects on human gastric cancer cells

By Qiang-Song Tong, Li-Duan Zheng, Liang Wang, Jun Liu and Wei Qian

Abstract

BACKGROUND: BAK (Bcl-2 homologous antagonist/killer) is a novel pro-apoptotic gene of the Bcl-2 family. It has been reported that gastric tumors have reduced BAK levels when compared with the normal mucosa. Moreover, mutations of the BAK gene have been identified in human gastrointestinal cancers, suggesting that a perturbation of BAK-mediated apoptosis may contribute to the pathogenesis of gastric cancer. In this study, we explored the therapeutic effects of gene transfer mediated elevations in BAK expression on human gastric cancer cells in vitro. METHODS: Eukaryotic expression vector for the BAK gene was constructed and transferred into gastric cancer cell lines, MKN-45 (wild-type p53) and MKN-28 (mutant-type p53). RT-PCR and Western Blotting detected cellular BAK gene expression. Cell growth activities were detected by MTT colorimetry and flow cytometry, while apoptosis was assayed by electronic microscopy and TUNEL. Western Blotting and colorimetry investigated cellular caspase-3 activities. RESULTS: BAK gene transfer could result in significant BAK overexpression, decreased in vitro growth, cell cycle G(0)/G(1 )arrest, and induced apoptosis in gastric cancer cells. In transferred cells, inactive caspase-3 precursor was cleaved into the active subunits p20 and p17, during BAK overexpression-induced apoptosis. In addition, this process occurred equally well in p53 wild-type (MKN-45), or in p53 mutant-type (MKN-28) gastric cancer cells. CONCLUSIONS: The data presented suggests that overexpression of the BAK gene can lead to apoptosis of gastric cancer cells in vitro, which does not appear to be dependent on p53 status. The action mechanism of BAK mediated apoptosis correlates with activation of caspase-3. This could be served as a potential strategy for further development of gastric cancer therapies

Topics: Research Article
Publisher: BioMed Central
Year: 2004
DOI identifier: 10.1186/1471-2407-4-33
OAI identifier: oai:pubmedcentral.nih.gov:481072
Provided by: PubMed Central

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Citations

  1. (1998). Antitumor activity of bax and p53 naked gene transfer in lung cancer: in vitro and in vivo analysis. Hum Gene Ther
  2. (2000). Apoptosis and cancer: strategies for integrating programmed cell death. Semin Hematol
  3. (2002). Bax and Bak independently promote cytochrome C release from mitochondria.
  4. (2004). Bax mediates the apoptosis-sensitizing effect of maspin. Cancer Res
  5. (1995). Cloning of a bcl-2 homologue by interaction with adenovirus E1B 19K. Nature
  6. (1997). D: New approaches to the treatment of gastro-intestinal cancer. Digestion
  7. (2003). Dive C: Mitochondrial membrane permeabilisation by Bax/BAK. Biochem Biophys Res Commun
  8. (1997). Dixit VM: Bik and Bak induce apoptosis downstream of CrmA but upstream of inhibitor of apoptosis.
  9. (1998). Downregulation of the pro-apoptotic protein BAK is required for the rasinduced transformation of intestinal epithelial cells. Curr Biol
  10. (1997). Expression of bcl-2 antagonist BAK in inflammatory and neoplastic skin diseases.
  11. (2004). Fujiwara T: Molecular therapy for peritoneal dissemination of xenotransplanted human MKN-45 gastric cancer cells with adenovirus mediated Bax gene transfer. Gut
  12. (2003). Gene therapy for gastric cancer: a review.
  13. (1998). Genomic structure and domain organisation of the human Bak gene. Gene
  14. (2003). Hockenbery DM: Targeting BCL-2-related proteins in cancer therapy. Cancer Biol Ther
  15. (2000). JA: Up-regulation of the proapoptotic mediators Bax and BAK after adenovirus- mediated p53 gene transfer in lung cancer cells. Clin Cancer Res
  16. (1996). JC: Immunohistochemical analysis of in vivo patterns of bak expression, a pro-apoptotic member of the Bcl-2 protein family. Cancer Res
  17. (2002). JM: IFN-gammaupregulates apoptosis-related molecules and enhances Fas-mediated apoptosis in human cholangiocarcinoma.
  18. (2002). Mechanisms of caspase activation and inhibition during apoptosis. Mol Cell
  19. (2004). Mutational analysis of the BAK gene in 192 advanced gastric and colorectal cancers.
  20. (2000). Mutations of the BAK gene in human gastric and colorectal cancers. Cancer Res
  21. (1995). PJ: Modulation of apoptosis by the widely distributed Bcl2 homologue Bak. Nature
  22. (2000). Programmed cell death regulation: basic mechanisms and therapeutic opportunities. Leukemia
  23. (2001). Rabinowich H: A role for mitochondrial Bak in apoptotic response to anticancer drugs.
  24. (2001). Rabinowich H: Resistance to granzyme B-mediated cytochrome c release in Bak-deficient cells.
  25. (1996). Reed JC: Immunohistochemical analysis of Bcl-2 family proteins in adenocarcinomas of the stomach.
  26. (2003). Regulation of apoptosis by Bcl-2 family proteins.
  27. (2000). SG: Adenoviral BAK overexpression mediates caspase-dependent tumor killing. Cancer Res
  28. (2003). The Bcl-2 family: roles in cell survival and oncogenesis. Oncogene

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