Induction of G1 and G2/M cell cycle arrests by the dietary compound 3,3'-diindolylmethane in HT-29 human colon cancer cells.

Abstract

BACKGROUND:

3,3'-Diindolylmethane (DIM), an indole derivative produced in the stomach after the consumption of broccoli and other cruciferous vegetables, has been demonstrated to exert anti-cancer effects in both in vivo and in vitro models. We have previously determined that DIM (0 - 30 micromol/L) inhibited the growth of HT-29 human colon cancer cells in a concentration-dependent fashion. In this study, we evaluated the effects of DIM on cell cycle progression in HT-29 cells.

METHODS:

HT-29 cells were cultured with various concentrations of DIM (0 - 30 micromol/L) and the DNA was stained with propidium iodide, followed by flow cytometric analysis. [3H]Thymidine incorporation assays, Western blot analyses, immunoprecipitation and in vitro kinase assays for cyclin-dependent kinase (CDK) and cell division cycle (CDC)2 were conducted.

RESULTS:

The percentages of cells in the G1 and G2/M phases were dose-dependently increased and the percentages of cells in S phase were reduced within 12 h in DIM-treated cells. DIM also reduced DNA synthesis in a dose-dependent fashion. DIM markedly reduced CDK2 activity and the levels of phosphorylated retinoblastoma proteins (Rb) and E2F-1, and also increased the levels of hypophosphorylated Rb. DIM reduced the protein levels of cyclin A, D1, and CDK4. DIM also increased the protein levels of CDK inhibitors, p21CIP1/WAF1 and p27KIPI. In addition, DIM reduced the activity of CDC2 and the levels of CDC25C phosphatase and cyclin B1.

CONCLUSION:

Here, we have demonstrated that DIM induces G1 and G2/M phase cell cycle arrest in HT-29 cells, and this effect may be mediated by reduced CDK activity.

• Authors: Hyun Ju Choi, Do Young Lim, Jung Han Yoon Park
• Journal: BMC gastroenterology (BMC Gastroenterol) Vol. 9 Pg. 39 (May 29 2009) ISSN: 1471-230X [Electronic] England
• PMID: 19480695 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anticarcinogenic Agents
• CDKN1A protein, human
• Cyclin A
• Cyclin B
• Cyclin-Dependent Kinase Inhibitor p21
• DNA, Neoplasm
• Indoles
• Cyclin D1
• Cyclin-Dependent Kinase Inhibitor p27
• CDC2 Protein Kinase
• CDK1 protein, human
• CDK2 protein, human
• CDK4 protein, human
• Cyclin-Dependent Kinase 2
• Cyclin-Dependent Kinase 4
• Cyclin-Dependent Kinases
• 3,3'-diindolylmethane

Topics

• Adenocarcinoma (pathology)
• Anticarcinogenic Agents (pharmacology)
• CDC2 Protein Kinase
• Cell Cycle (drug effects)
• Cell Division (drug effects)
• Cell Line, Tumor
• Colonic Neoplasms (pathology)
• Cyclin A (metabolism)
• Cyclin B (metabolism)
• Cyclin D1 (metabolism)
• Cyclin-Dependent Kinase 2 (metabolism)
• Cyclin-Dependent Kinase 4 (metabolism)
• Cyclin-Dependent Kinase Inhibitor p21 (metabolism)
• Cyclin-Dependent Kinase Inhibitor p27 (metabolism)
• Cyclin-Dependent Kinases
• DNA, Neoplasm (drug effects, metabolism)
• Dose-Response Relationship, Drug
• G1 Phase (drug effects)
• G2 Phase (drug effects)
• HT29 Cells
• Humans
• Indoles (pharmacology)