Growth-inhibitory effects of a β-glucan from the mycelium of Poria cocos on human breast carcinoma MCF-7 cells: Cell-cycle arrest and apoptosis induction

  • Authors:
    • Mei Zhang
    • Lawrence C.-M. Chiu
    • Peter C.K. Cheung
    • Vincent E.C. Ooi
  • View Affiliations

  • Published online on: March 1, 2006     https://doi.org/10.3892/or.15.3.637
  • Pages: 637-643
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Abstract

Because of the reported immune-enhancing and anti-tumor activities of some mushroom polysaccharides, their applications as biological response modifiers have attracted significant attention. We have purified a water-soluble β-glucan PCM3-II, comprising mainly 1↷3 and 1↷4 linkages, from the mycelia of Poria cocos (Schw.) Wolf (Fu-ling). In this study, the growth-inhibitory effect of PCM3-II was further explored on the human breast carcinoma MCF-7 cells in vitro. The dose effect of PCM3-II was studied by incubating the breast cancer cells with 12.5-400 µg/ml of the glucan for 72 h. The MTT study showed that PCM3-II reduced proliferation and viability of the MCF-7 cells dose-dependently, so that the cancer-cell growth was decreased by 50% of the control level at 400 µg/ml of the glucan. The time effect of PCM3-II was then investigated by treating the breast cancer cells with 400 µg/ml of the glucan for 24, 48 and 72 h, respectively. Results from the flow cytometry study demonstrated that PCM3-II induced cell-cycle G1 arrest time-dependently and about 90% of the cells in cell cycle were accumulated at G1 phase after 72 h of treatment. The G1 arrest was associated with downregulations of the unscheduled cyclin D1 and cyclin E expressions in the breast cancer cells. Apoptosis was also induced by PCM3-II in the MCF-7 cells, so that the subG1 cells in DNA histogram of the flow cytometry were elevated by 5-fold of the control level at 48 h and by 24-fold at 72 h of treatment. The immunoblot study also showed that the glucan induced depletion of the antiapoptotic Bcl-2 protein, but not the proapoptotic Bax protein, so that the Bax/Bcl-2 ratio was elevated in the breast cancer cells at the time when the most prominent apoptosis was also observed. In conclusion, although the detailed mechanism for the anti-tumor activity of the P. cocos β-glucan still needs further investigation, this study provides preliminary insights into its mode of action and perspectives of its development as a water-soluble anti-tumor agent.

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March 2006
Volume 15 Issue 3

Print ISSN: 1021-335X
Online ISSN:1791-2431

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Spandidos Publications style
Zhang M, Chiu LC, Cheung PC and Ooi VE: Growth-inhibitory effects of a β-glucan from the mycelium of Poria cocos on human breast carcinoma MCF-7 cells: Cell-cycle arrest and apoptosis induction. Oncol Rep 15: 637-643, 2006
APA
Zhang, M., Chiu, L.C., Cheung, P.C., & Ooi, V.E. (2006). Growth-inhibitory effects of a β-glucan from the mycelium of Poria cocos on human breast carcinoma MCF-7 cells: Cell-cycle arrest and apoptosis induction. Oncology Reports, 15, 637-643. https://doi.org/10.3892/or.15.3.637
MLA
Zhang, M., Chiu, L. C., Cheung, P. C., Ooi, V. E."Growth-inhibitory effects of a β-glucan from the mycelium of Poria cocos on human breast carcinoma MCF-7 cells: Cell-cycle arrest and apoptosis induction". Oncology Reports 15.3 (2006): 637-643.
Chicago
Zhang, M., Chiu, L. C., Cheung, P. C., Ooi, V. E."Growth-inhibitory effects of a β-glucan from the mycelium of Poria cocos on human breast carcinoma MCF-7 cells: Cell-cycle arrest and apoptosis induction". Oncology Reports 15, no. 3 (2006): 637-643. https://doi.org/10.3892/or.15.3.637