This study investigated that whether a 2 mT, 60 Hz, sinusoidal electromagnetic field (EMF) alters the structure and function of cells. This research compared the effects of EMF on four kinds of cell lines: hFOB 1.19 (fetal osteoblast), T/G HA-VSMC (aortic vascular smooth muscle cell), RPMI 7666 (B lymphoblast), and HCN-2 (cortical neuronal cell). Over 14 days, cells were exposed to EMF for 1, 3, or 6 hours per day (hrs/d). The results pointed to a cell type-specific reaction to EMF exposure. In addition, the cellular responses were dependent on duration of EMF exposure. In the present study, cell proliferation was the trait most sensitive to EMF. EMF treatment promoted growth of hFOB 1.19 and HCN-2 compared with control cells at 7 and 14 days of incubation. When the exposure time was 3 hrs/d, EMF enhanced the proliferation of RPMI 7666 but inhibited that of T/G HA- VSMC. On the other hand, the effects of EMF on cell cycle distribution, cell differentiation, and actin distribution were unclear. Furthermore, we hardly found any correlation between EMF exposure and gap junctional intercellular communication in hFOB 1.19. This study revealed that EMF might serve as a potential tool for manipulating cell proliferation.
Signal Transduction ; Microfilaments/radiation effects ; Humans ; Gap Junctions/metabolism/radiation effects ; *Electromagnetic Fields ; Cell Proliferation/radiation effects ; Cell Physiology/*radiation effects ; Cell Line ; Cell Differentiation/radiation effects ; Cell Cycle/radiation effects

This study investigated that whether a 2 mT, 60 Hz, sinusoidal electromagnetic field (EMF) alters the structure and function of cells. This research compared the effects of EMF on four kinds of cell lines: hFOB 1.19 (fetal osteoblast), T/G HA-VSMC (aortic vascular smooth muscle cell), RPMI 7666 (B lymphoblast), and HCN-2 (cortical neuronal cell). Over 14 days, cells were exposed to EMF for 1, 3, or 6 hours per day (hrs/d). The results pointed to a cell type-specific reaction to EMF exposure. In addition, the cellular responses were dependent on duration of EMF exposure. In the present study, cell proliferation was the trait most sensitive to EMF. EMF treatment promoted growth of hFOB 1.19 and HCN-2 compared with control cells at 7 and 14 days of incubation. When the exposure time was 3 hrs/d, EMF enhanced the proliferation of RPMI 7666 but inhibited that of T/G HA- VSMC. On the other hand, the effects of EMF on cell cycle distribution, cell differentiation, and actin distribution were unclear. Furthermore, we hardly found any correlation between EMF exposure and gap junctional intercellular communication in hFOB 1.19. This study revealed that EMF might serve as a potential tool for manipulating cell proliferation.
Signal Transduction ; Microfilaments/radiation effects ; Humans ; Gap Junctions/metabolism/radiation effects ; *Electromagnetic Fields ; Cell Proliferation/radiation effects ; Cell Physiology/*radiation effects ; Cell Line ; Cell Differentiation/radiation effects ; Cell Cycle/radiation effects

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.
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

OBJECTIVETo prepare nanoparticles containing E1A gene and observe the efficiency and feasibility of transfecting E1A gene into human undifferentiated thyroid cancer cell line HTC/3. To examine the sensitivity of transgene cells to X-ray and X-ray-induced apoptosis in those cells.

METHODSNanoparticle-DNA complex was prepared with PLGA coating adenoviral early expression gene E1A, and the package efficiency, release progress in vitro, and size of the complex were determined. The nanoparticle-DNA was transfected into the HTC/3 cells. Lipofectamine was used to transfect E1A gene as a control. RT-PCR was used to examine E1A gene mRNA expression in the transfected cells. The survival ratio of HTC/3-E1A and control cells, and the growth inhibition ratio induced by different doses of X-ray in HTC/3-E1A cells were examined by MTT assay. The apoptosis in HTC/3-E1A cells induced by 2 Gy X-ray iradiation was examined by flow cytometry and DNA electrophoresis.

RESULTSThe package efficiency, release progress in vitro, and size of the nanoparticle-DNA complex were 0.78%, 18 days, and 150-280 nm, respectively when transfected the plasmid at the same level, the nanoparticle group got more positive transgene cell clones than that in lipofectamine group, with a statistically significant difference (P < 0.05). RT-PCR showed that transgenic cells from both nanoparticle-DNA and lipofectamine groups had E1A gene mRNA expression. The HTC/3-E1A cells grew slowly, and their doubling time was prolongated (1.44 times in comparison with that in parental cells). According to IC50, the sensitivity of HTC/3-E1A cells to X-ray was improved 2.9 and 2.8 times, respectively, in comparison with that in HTC/3-Vect and HTC/3 cells. The ratio of subG0/G1 phase of HTC/3-E1A cells was significantly higher than that in HTC/3-Vect and HTC/3 cells (P < 0.01). The ratio of S phase of HTC/3-E1A cells was significantly lower than that in HTC/3-Vect and HTC/3 cells (P < 0.01). A typical DNA ladder pattern of apoptosis in HTC/3-E1A cells was observed by electrophoresis, but not found in HTC/3-Vect and HTC/3 cells.

CONCLUSIONA nanoparticle-DNA complex has been successfully prepared, and it may carry a foreign gene into cells. The sensitivity of HTC/3-E1A cells to X-ray is significantly improved. Moreover, apoptosis is induced by x-ray in the E1A gene-transfected cells.

Adenovirus E1A Proteins ; biosynthesis ; genetics ; physiology ; Apoptosis ; radiation effects ; Cell Cycle ; radiation effects ; Cell Line, Tumor ; Cell Proliferation ; DNA ; genetics ; Humans ; Lactic Acid ; chemistry ; Nanoparticles ; Particle Size ; Plasmids ; Polyglycolic Acid ; chemistry ; RNA, Messenger ; metabolism ; Thyroid Neoplasms ; metabolism ; pathology ; Transfection ; X-Rays