Inhibitory Mechanisms of Cell Cycle Regulation Induced by Indole-3-carbinol in Hepatocellular Carci-noma HepG2 Cells.

간암 세포주에서의 Indole-3-Carbinol에 의해 유도되는 세포주기 억제 기전

  • 김동우 (한양대학교 의과대학 일반외과교실) ;
  • 이광수 (한양대학교 의과대학 일반외과교실) ;
  • 김민경 (유전학교실 및 의과학연구소) ;
  • 조율희 (유전학교실 및 의과학연구소) ;
  • 이철훈 (유전학교실 및 의과학연구소)
  • Published : 2001.09.01

Abstract

The naturally occurring chemical indole-3-carbinol (13C), found in vegetables of the Brassica genus, is a promising anticancer agent that was shown previ- ously to induce a Gl cell cycle arrest of human breast cancer cell lines, independent of estrogen receptor signaling. The anticancer activity of 13C and the possible mechanisms of its action were explored in a human hepatocellular carcinoma cell line, HepG2. Treatment of HepG2 cells with 13C suppressed the growth of the cells. The growth sup- pression caused by 13C ($IC_{50}$/: 444$\mu$M) was found to be partially due to its ability to stop the cell cycle in HepG2 cells. Western blot analysis for the Gl phase artiest demonstrated that the expression-levels of cyclin-dependent kinase (Cdk4, Cdk6) and cyclic D were reduced strongly after treatment of Hep72 cells with 13C (4007M) for 24- 72 hrs. Furthermore, I3C selectively abolished the expression of Cdk6 in a dose- and time-dependent manner, and accordingly, inhibited the phosphorylation of retinoblastoma. Interestingly, after the HepG2 cells reached their max- imal growth arrest, the level of the p21, a well-known Cdk inhibitor, increased significantly. Therefore, it could be considered that the Gl arrest of HepG2 cells treated with 13C was due to the indirect inhibition of Cdk4/6 activities by p21 Western blot analysis for G2/M phase arrest of demonstrated the levels of Cdc2 and cyclin Bl werer reduced dramatically after the treatment of HepG2 cells with 13C ($40\mu$M) for 24-72 hrs. flow cytometry of propidium iodide-stained HepG2 cells revealed that 13C induces a Gl (53%,72hr incubation) and G2 (25%,24hr incubation) cell cycle arrest. Thus, our observations have uncovered a previously undefined antiproliferative pathway for r3C that implicates Cdk4/6 and Cdc2 as a target for cell cycle control in human HepG2 cells. However, the 13C-medi- ated cell cycle arrest and repression of Cdk4/6 production did not affect the apoptotic induction of HepG2 cell.

Keywords

Indole-3-carbinol;cell cycle regulation;HepG2 cells

References

  1. J. Biol. Chem v.273 Indole-3-carbinol inhibits the expression of cyclin-dependent kinase-6 and induces a G1 cell cycle arrest of human breast cancer cells independent of estrogen receptor signaling Cover, C. M.;S. J. Hsieh;S. H. Tran;G. Hallden;G. S. Kim;L. F. Bjeldanes;G. L. Firestone
  2. Chemico-Biol. Interact. v.110 Indle-3-carbinol: Anticarcinogen or tumor promoter in brassica vegetables? Dashwood, R. H.
  3. Science v.274 Cancer cell cycles Sherr, C. J.
  4. FEBS Lett. v.410 Communication between the extracellular environment, cytoplasmic signalling cascades and the nuclesr cell-cycle machinery Peeper, D. S;R. Bernards
  5. Nat. Med. v.4 Understanding the cell cycle Nurse, P.;Y. Masui;L. Hartwell
  6. science v.274 Viewpoint : putting the cell cycle on order Nasmyth, K.
  7. Nature v.396 Cell suicide for beginners Raff, M.
  8. Anticancer Res. v.19 Anti-estrogenic activities of indole-3-carbinol in cervical cells: Implication for prevention of cervical cancer Yuan, F.;D. Z. Chen;K. Liu;D. W. Sepkovic;H. L. Bradlow;K. Auborn
  9. Int. J. Biochem. Cell Biol. v.29 Regulation of CDK/cyclin complexes during the cell cycle Arellano, M.;S. Moreno
  10. Trends Cell Biol. v.6 Chemical inhibitors of cyclin-dependent Kinases Meijer, L.
  11. Adv. Cancer Res. v.68 Genetic alterations of cyclins, cyclin-dependent kinases,and Cdk inhibitors in human cancer Hall, M.;G. Peters
  12. Curr. Opin. Cell Biol. v.7 Cyclin dependent kinase regulation Lees, E.
  13. Oncogene Report. v.5 Inhibition of aberrant proliferation and induction of apoptosis in preneoplastic human mammary epithelial cells by natural phytochemicals Katdare, M.;M. P.Osborne;N. T. Telang
  14. Mol. Cell. Biol. v.17 Ras links growth factor signaling to the cell cycle machinery via regulation of cyclin D1 and the Cdk inhibitor p27KIP1 Aktas, H.;H. Cai;G. M. Cooper
  15. Cancer. J. Sci. Am. v.4(Suppl 1) Control of eukaryotic cell cycle progression by phosphorylation of cyclin-dependent kinases Morgan, D. O.;R. P. Fisher;F. H. Espinoza
  16. Cancer Res. v.59 Indole-3-carbinol and tamoxifen cooperate to arrest the cell cycle of MCF-7 human breast cancer cells Cover, C. M.;S. J. Hsieh;E. J. Cram;C. Hong;J. E. Riby;L. F. Bjeldanes;G. L. Firestone
  17. Gan To Kagaku Ryoho v.22 Cell cycle regulation by anticancer agent Nomoto, T.;K. Nishio;N. Saijo
  18. Science. v.274 Cell cycle checkpoints: prevention an identity crisis Elledge, S. J.
  19. Anticancer Res. v.19 Induction of apoptosis in MCF-7 cells by indole-3-carbinol is independint of p53 and bax Ge, X.;F. A. Fares;S. Yannai
  20. Nature v.374 Principles of CDK regulation Morgan, D. O.