Cancer Chemotherapy and Pharmacology

, Volume 57, Issue 3, pp 317–327

p53-independent G1 cell cycle arrest of human colon carcinoma cells HT-29 by sulforaphane is associated with induction of p21CIP1 and inhibition of expression of cyclin D1

Authors

  • Guoxiang Shen
    • Department of Pharmaceutics, Ernest Mario School of PharmacyRutgers, The State University of New Jersey
  • Changjiang Xu
    • Department of Pharmaceutics, Ernest Mario School of PharmacyRutgers, The State University of New Jersey
  • Chi Chen
    • Department of Pharmaceutics, Ernest Mario School of PharmacyRutgers, The State University of New Jersey
  • Vidya Hebbar
    • Department of Pharmaceutics, Ernest Mario School of PharmacyRutgers, The State University of New Jersey
    • Department of Pharmaceutics, Ernest Mario School of PharmacyRutgers, The State University of New Jersey
Original Article

DOI: 10.1007/s00280-005-0050-3

Cite this article as:
Shen, G., Xu, C., Chen, C. et al. Cancer Chemother Pharmacol (2006) 57: 317. doi:10.1007/s00280-005-0050-3
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Abstract

Isothiocyanate sulforaphane (SFN) is a potent cancer chemopreventive agent. We investigated the mechanisms underlying the anti-proliferative effects of SFN in the human colon carcinoma cell line, HT-29. We demonstrate that SFN inhibits the growth of HT-29 cells in a dose- and time-dependent manner. Treatment of serum-stimulated HT-29 cells with SFN suppressed the re-initiation of cell cycle by inducing a G1 phase cell cycle arrest. At high doses (>25 μM), SFN dramatically induces the expression of p21CIP1 while significantly inhibits the expression of the G1 phase cell cycle regulatory genes such as cyclin D1, cyclin A, and c-myc. This regulation can be detected at both the mRNA and protein levels as early as 4 h post-treatment of SFN at 50 μM. Additionally, SFN activates MAPKs pathways, including ERK, JNK and p38. Exposure of HT-29 cells with both SFN and an antioxidant, either NAC or GSH, completely blocked the SFN-mediated activation of these MAPK signaling cascades, regulation of cyclin D1and p21CIP1 gene expression, and G1phase cell cycle arrest. This finding suggests that SFN-induced oxidative stress plays a role in these observed effects. Furthermore, the activation of the ERK and p38 pathways by SFN is involved in the upregulation of p21CIP1 and cyclin D1, whereas the activation of the JNK pathway plays a contradictory role and may be partially involved in the downregulation of cyclin D1. Because cyclin D1 and p21CIP1 play opposing roles in G1 phase cell cycle progression regulation, blocking the activation of each MAPK pathway with specific MAPK inhibitors, is unable to rescue the SFN-induced G1 phase cell cycle arrest in HT-29 cells.

Keywords

SulforaphaneCell cycle arrestHT-29 cellsMitogen-activated protein kinase

Abbreviations

SFN

Sulforaphane

MAPK

Mitogen-activated protein kinase

NF-κB

Nuclear factor-kappa B

GSH

Glutathione

NAC

N-acetyl-L-cysteine

MTS

3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt

ERK

Extracellular signal-regulated protein kinase JNK, c-Jun NH2-terminal kinase

Copyright information

© Springer-Verlag 2005