Bax overexpression enhances cytochrome c release from mitochondria and sensitizes KATOIII gastric cancer cells to chemotherapeutic agent-induced apoptosis.

  • Authors:
    • H Sawa
    • T Kobayashi
    • K Mukai
    • W Zhang
    • H Shiku
  • View Affiliations

  • Published online on: April 1, 2000     https://doi.org/10.3892/ijo.16.4.745
  • Pages: 745-754
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Abstract

To evaluate whether overexpression of Bax, an apoptosis-promoting gene, sensitizes KATOIII gastric cancer cells to apoptosis induced by chemotherapeutic agents, three stable cell lines of KATOIII transfected with Bax (KATOIII-Bax), Bcl-2 (KATOIII-Bcl-2), or control pCI-neo expression vector (KATOIII-pCI-neo) were established. The cells were treated with paclitaxel, 5-fluorouracil, or doxorubicin, and the apoptotic response was measured. Our results showed that the sensitivity of the KATOIII-Bax cells to chemotherapeutic agents was enhanced compared with that of the KATOIII-pCI-neo cells, and the KATOIII-Bcl-2 cells were more resistant to these agents. Western blotting revealed that cytochrome c level in the cytosol fraction of the KATOIII-Bax cells was higher than that of the KATOIII-pCI-neo cells. Significant increase of cytochrome c level in the cytosol fraction of the KATOIII-Bax cells was detected 24 h after exposure to chemotherapeutic agents, when apoptotic cells were less than 10%. The cytochrome c level in the cytosol fraction of the KATOIII-Bax cells was higher than that of the KATOIII-pCI-neo cells at all time points examined after exposure to chemotherapeutic agents. Marked activation of caspase-3 in the KATOIII-Bax cells was observed 48 h and 72 h after exposure to chemotherapeutic agents compared with that in the KATOIII-pCI-neo cells. Consistently, zVAD-fmk, a pancaspase inhibitor, repressed the paclitaxel-induced apoptosis. In addition, Bcl-2 overexpression strongly blocked KATOIII cell apoptosis by inhibiting the cytochrome c release from mitochondria and caspase-3 activation. These findings suggest that cytochrome c release is a major mechanism of apoptotic response and Bax overexpression sensitizes KATOIII cells to chemotherapeutic agent-induced apoptosis through enhancing the release of cytochrome c from mitochondria.

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April 2000
Volume 16 Issue 4

Print ISSN: 1019-6439
Online ISSN:1791-2423

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APA
Sawa, H., Kobayashi, T., Mukai, K., Zhang, W., & Shiku, H. (2000). Bax overexpression enhances cytochrome c release from mitochondria and sensitizes KATOIII gastric cancer cells to chemotherapeutic agent-induced apoptosis.. International Journal of Oncology, 16, 745-754. https://doi.org/10.3892/ijo.16.4.745
MLA
Sawa, H., Kobayashi, T., Mukai, K., Zhang, W., Shiku, H."Bax overexpression enhances cytochrome c release from mitochondria and sensitizes KATOIII gastric cancer cells to chemotherapeutic agent-induced apoptosis.". International Journal of Oncology 16.4 (2000): 745-754.
Chicago
Sawa, H., Kobayashi, T., Mukai, K., Zhang, W., Shiku, H."Bax overexpression enhances cytochrome c release from mitochondria and sensitizes KATOIII gastric cancer cells to chemotherapeutic agent-induced apoptosis.". International Journal of Oncology 16, no. 4 (2000): 745-754. https://doi.org/10.3892/ijo.16.4.745