3,3'Diindolylmethane suppresses vascular smooth muscle cell phenotypic modulation and inhibits neointima formation after carotid injury.

Abstract

BACKGROUND:

3,3'Diindolylmethane (DIM), a natural phytochemical, has shown inhibitory effects on the growth and migration of a variety of cancer cells; however, whether DIM has similar effects on vascular smooth muscle cells (VSMCs) remains unknown. The purpose of this study was to assess the effects of DIM on the proliferation and migration of cultured VSMCs and neointima formation in a carotid injury model, as well as the related cell signaling mechanisms.

METHODOLOGY/PRINCIPAL FINDINGS:

DIM dose-dependently inhibited the platelet-derived growth factor (PDGF)-BB-induced proliferation of VSMCs without cell cytotoxicity. This inhibition was caused by a G0/G1 phase cell cycle arrest demonstrated by fluorescence-activated cell-sorting analysis. We also showed that DIM-induced growth inhibition was associated with the inhibition of the expression of cyclin D1 and cyclin-dependent kinase (CDK) 4/6 as well as an increase in p27(Kip1) levels in PDGF-stimulated VSMCs. Moreover, DIM was also found to modulate migration of VSMCs and smooth muscle-specific contractile marker expression. Mechanistically, DIM negatively modulated PDGF-BB-induced phosphorylation of PDGF-recptorβ (PDGF-Rβ) and the activities of downstream signaling molecules including Akt/glycogen synthase kinase(GSK)3β, extracellular signal-regulated kinase1/2 (ERK1/2), and signal transducers and activators of transcription 3 (STAT3). Our in vivo studies using a mouse carotid arterial injury model revealed that treatment with 150 mg/kg DIM resulted in significant reduction of the neointima/media ratio and proliferating cell nuclear antigen (PCNA)-positive cells, without affecting apoptosis of vascular cells and reendothelialization. Infiltration of inflammatory cells was also inhibited by DIM administration.

CONCLUSION:

These results demonstrate that DIM can suppress the phenotypic modulation of VSMCs and neointima hyperplasia after vascular injury. These beneficial effects on VSMCs were at least partly mediated by the inhibition of PDGF-Rβ and the activities of downstream signaling pathways. The results suggest that DIM has the potential to be a candidate for the prevention of restenosis.

• Authors: Hongjing Guan, Lihua Zhu, Mingyue Fu, Da Yang, Song Tian, Yuanyuan Guo, Changping Cui, Lang Wang, Hong Jiang
• Journal: PloS one (PLoS One) Vol. 7 Issue 4 Pg. e34957 ( 2012) ISSN: 1932-6203 [Electronic] United States
• PMID: 22506059 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Indoles
• Proliferating Cell Nuclear Antigen
• Proto-Oncogene Proteins c-sis
• p27 antigen
• Cyclin D1
• Becaplermin
• Cyclin-Dependent Kinases
• 3,3'-diindolylmethane

Topics

• Animals
• Apoptosis (drug effects)
• Becaplermin
• Carotid Artery Diseases (drug therapy, metabolism, pathology)
• Cell Cycle Checkpoints (drug effects)
• Cell Movement (drug effects)
• Cell Proliferation (drug effects)
• Cells, Cultured
• Cyclin D1 (metabolism)
• Cyclin-Dependent Kinases (metabolism)
• G1 Phase (drug effects)
• Human Umbilical Vein Endothelial Cells (drug effects, metabolism, pathology)
• Humans
• Indoles (pharmacology)
• Inflammation (drug therapy, metabolism)
• Male
• Mice
• Muscle, Smooth, Vascular (drug effects, metabolism, pathology)
• Myocytes, Smooth Muscle (drug effects, metabolism, pathology)
• Neointima (drug therapy, metabolism, pathology)
• Phosphorylation (drug effects)
• Proliferating Cell Nuclear Antigen (metabolism)
• Proto-Oncogene Proteins c-sis (metabolism)
• Rats, Sprague-Dawley
• Resting Phase, Cell Cycle (drug effects)
• Signal Transduction (drug effects)