Exp Mol Med.  2005 Feb;37(1):18-26.

NF-kappa B decoy potentiates the effects of radiation on vascular smooth muscle cells by enhancing apoptosis

• Zhang SY
• Park KW
• Oh S
• Cho HJ
• Cho HJ
• Park JS
• Cho YS
• Koo BK
• Chae IH
• Choi DJ
• Kim HS
• Lee MM

Abstract

NF-kappa B promotes cell survival against external stress such as radiation. We examined whether NF-kappa B decoy transfection enhances the antiproliferative effects of radiation on vascular smooth muscle cells (VSMCs) in vitro. The irradiation induced activation or nuclear translocation of NF-kappa B p65 in VSMCs was confirmed by immunofluorescence. NF-kB decoy transfection resulted in inhibition of the radiation-induced NF-kB activation in VSMCs and the subsequent reduction of transcription and translocation of ICAM, iNOS, and TNF-alpha, downstream molecules under the control of NF-kappa B. By using MTT assay, NF-kappa B decoy augmented the antiproliferative effects of radiation, where the effect of low dose radiation (2 and 8-Gy) of the cells transfected with NF-kappa B decoy was equivalent to the high dose (16-Gy) irradiated non-transfected cells at 48 h after irradiation: 1.06+/-0.16, 1.11+/-0.22, 1.20+/-0.25, respectively. The decrease in proliferation and survival of the radiation treated cells by flow cytometry analysis showed that NF-kappa B inhibition did not show any additive effects on the cell cycle of the irradiated VSMCs, while apoptosis was significantly increased after NF-kappa B decoy transfection in the irradiated VSMCs (apoptosis fraction: 13.33+/-2.08% vs. 26.29+/-7.43%, for radiation only vs. radiation+NF-kappa B decoy transfection, P < 0.05). In addition, at 48 h, NF-kappa B decoy transfection dose dependently (10 mM vs. 20 mM) inhibited proliferation of 16Gy-irradiated VSMCs, and showed greater antiproliferative efficacy than 100 mM sulfasalazine, a specific NF-kappa B inhibitor. These results indicate that NF-kappa B inhibition reduces proliferation and survival of irradiated VSMCs, likely by increased apoptosis rather than additive cell cycle arrest and suggest the possibility of adjunctive gene therapy using NF-kappa B decoy to improve efficacy and to decrease the adverse effects of intracoronary radiation therapy.

Keyword

gene therapy; NF-kappa B; radiation; vascular smooth muscle cells

MeSH Terms

Animals
Aorta/cytology/radiation effects
*Apoptosis
Cell Cycle/physiology/radiation effects
Cell Proliferation/radiation effects
Cells, Cultured
Gamma Rays
Intercellular Adhesion Molecule-1/metabolism
Male
Muscle, Smooth, Vascular/cytology/physiology/*radiation effects
Myocytes, Smooth Muscle/cytology/radiation effects
NF-kappa B/*antagonists & inhibitors/metabolism
Nitric-Oxide Synthase/metabolism
Protein Transport
Rats
Rats, Sprague-Dawley
Research Support, Non-U.S. Gov't
Transcription, Genetic
Transfection
Tumor Necrosis Factor-alpha/metabolism