OBJECTIVETo study the effect of dihydroartemisinin (DHA) combined irradiation on the apoptosis of human lung cancer GLC-82 cells and to study its mechanism.

METHODSThe growth inhibition rate of GLC-82 cells acted by different concentrations DHA was detected using MTT assay at 24, 48, and 72 h, respectively. Clone forming test was used. With multi-target single-hit model, the radiosensitization effect was assessed by calculating sensitizing enhancement ratio (SER).The effect of DHA combined irradiation on the apoptosis of GLC-82 cell cycle distribution and apoptosis were measured by flow cytometry. The protein expression of p53, p21, Bcl-2, and Bax were detected by Western blot.

RESULTSDifferent concentrations DHA (4, 8, 16, 32, 64, and 128 μg/mL) had cytotoxicity on GLC-82 cells. The IC50 for 24, 48, and 72 h was 38.25,20.58, and 10.36 μg/mL, respectively, in obvious dose- and time-dependent manner. The growth inhibition rate was more significantly increased than that of the blank control group (P < 0.01, P<0.05). DHA had sensitization enhancement effect on GLC-82 cells, with SER of 1.4. DHA combined irradiation could obviously change the structure of GLC-82 cells cell cycle and induce apoptosis (with the apoptosis rate of 21.5%), which was significantly different from that of the blank control group (P < 0.05). Western blot showed the expression of p53 and p21 protein could be increased by DHA combined irradiation, and the expression of Bcl-2 protein down-regulated (P <0.01, P <0. 05).

CONCLUSIONSDHA had stronger cytotoxicity and radiosensitization on GLC-82 cells. Its mechanisms might lie in making the arrest of GLC-82 cells' growth at G0/G1 phase, decreasing the ratio of cells at S phase, restoring the function of p53, decreasing the expression of Bcl-2 protein, and inducing apoptosis in GLC-82 cells.

Apoptosis ; drug effects ; Artemisinins ; pharmacology ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Down-Regulation ; drug effects ; Flow Cytometry ; Humans ; Lung Neoplasms ; metabolism ; Neoplasm Proteins ; metabolism ; Radiation-Sensitizing Agents ; pharmacology ; Tumor Cells, Cultured ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo explore the relationship between microglial proinflammatory and electromagnetic radiation and unveil the role of microglia in microwave radiation induced central nervous system injury.

METHODSN9 microglia cells cultured in vitro were exposed to microwave at 90 mW/cm2. Cell flow cytometry was used to observe the expression of CD11b at different time points after exposure; ELISA was used to detect the concentration of TNF-alpha in N9 cell culture supernatant; RT-PCR analysis confirmed iNOS mRNA expression in N9 microglia cells; and Nitrate Reductase Method was used to test NO amount in culture supernatant.

RESULTSThe CD11b positive microglial cells increased significantly at 3 h after microwave exposure (P < 0.05), continued to increase until 24 h and peaked at 6 h after exposure. The amount of TNF-alpha rose dramatically from 1 h to 24 h after exposure (P < 0.01) and peaked at 3 h [(762.1 +/- 61.5) pg/ml] after exposure (P < 0.01). The level of NO started to increase at 1 h [(4.48-0.59) micromol/L] and lasted for 24 h after exposure. The expression of iNOS mRNA increased significantly at 1 h (P < 0.05), and tripled the original expression at 6 h after exposure, hereafter, it decreased slightly, but all were higher than the control group within 24 h after exposure.

CONCLUSIONMicrowave radiation could induce the activation of microglia cells. The activated microglia cells could induce microglial proinflammatory by producing large amounts of TNF-alpha, NO, etc.

Animals ; Cell Line ; Cells, Cultured ; Mice ; Microglia ; metabolism ; radiation effects ; Microwaves ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Phosphorylation ; RNA, Messenger ; genetics ; Tumor Necrosis Factors ; metabolism

In eukaryotic cells, DNA damage triggers activation of checkpoint signaling pathways that coordinate cell cycle arrest and repair of damaged DNA. These DNA damage responses serve to maintain genome stability and prevent accumulation of genetic mutations and development of cancer. The p38 MAPK was previously implicated in cellular responses to several types of DNA damage. However, the role of each of the four p38 isoforms and the mechanism for their involvement in DNA damage responses remained poorly understood. In this study, we demonstrate that p38γ, but not the other p38 isoforms, contributes to the survival of UV-treated cells. Deletion of p38γ sensitizes cells to UV exposure, accompanied by prolonged S phase cell cycle arrest and increased rate of apoptosis. Further investigation reveal that p38γ is essential for the optimal activation of the checkpoint signaling caused by UV, and for the efficient repair of UV-induced DNA damage. These findings have established a novel role of p38γ in UV-induced DNA damage responses, and suggested that p38γ contributes to the ability of cells to cope with UV exposure by regulating the checkpoint signaling pathways and the repair of damaged DNA.
Animals ; Apoptosis ; Cell Cycle Proteins ; metabolism ; Cells, Cultured ; DNA Damage ; DNA Repair ; Enzyme Activation ; Fibroblasts ; metabolism ; radiation effects ; Gene Deletion ; Histones ; metabolism ; Mice ; Mitogen-Activated Protein Kinase 12 ; genetics ; metabolism ; Phosphorylation ; S Phase ; Tumor Suppressor Protein p53 ; metabolism ; Ultraviolet Rays

This study sought to shed light on the killing effect of peripheral blood mononuclear cells (PBMCs) irradiated by gamma ray at a dose of 1 Gy on cultured human gastric tumor cell line MKN-28. The radiation dose rate of 17 Gy/min was used. The groups in the experiment were MKN-28 cell control group, PBMCs control group, MKN-28 tumor cells with irradiated or non-irradiated PBMCs co-cultured groups. Radiation dosage was one Gray, acridine orange/ethidium bromide (AO/EB) staining was used for observation of the killing effects of PBMCs on tumor cells in different period. Cells were harvested 240 h later and observed by transmission electron microscopy. The result showed the living period of irradiated PBMCs was shorter than that of non-irradiated PBMCs. In the irradiated and non-irradiated groups,a few PBMCs were still alive after being cultured for 240 h, but the cell volume was larger than that of lymphocytes. These cells were identified as monocytes (95%) or DCs (5%) by transmission electron microscopy. The co-culture of irradiated PBMCs and MKN-28 cells showed that tumor cells were eliminated after 96 h. As compared with the non-irradiated goup, the irradiated PBMCs had more potent ability for killing tumor. The results demonstrate that 1 Gy gamma irridiation can improve the killing effect of PBMCs on the tumor cells, and that 1 Gy gamma irritation can also induce shorter living period of lymphocytes in PBMCs cultured in vitro, but such irritation has little effect on the living period of monocytes and DCs in PBMCs.
Cell Survival ; Coculture Techniques ; Gamma Rays ; Humans ; Leukocytes, Mononuclear ; cytology ; immunology ; radiation effects ; Stomach Neoplasms ; immunology ; pathology ; Tumor Cells, Cultured

This experiment was designed to study the apoptosis and related mechanism of adherent liver tumor cells (SMMC-7721) and adherent normal liver cells (HL-7702) when they were exposed to the steep pulse generated by the steep pulse apparatus for tumor treatment. The results showed that the steep pulse of 200 V could induce tumor cells apoptosis. The tumor cells presented with their apoptosis when they were exposed to the steep pulse from 200 V to 250 V. Laser scanning confocal microscopy was used to make a real time study of calcium burst when the adherent tumor cells were exposed to the steep pulse. The results showed:On the condition of no extracellular Ca2+, the concentration of Ca2+ in tumor cells exposed to the steep pulse of 150 V did not change; the concentration of Ca2+ in tumor cells exposed to the steep pulse of 200 V decreased; the concentration of Ca2+ in tumor cells exposed to the steep pulse of 250 V decreased more evidently. On the condition of existing extracellular Ca2+, the concentration of Ca2+ in tumor cells exposed to the steep pulse of 150 V did not change; the concentration of Ca2+ in tumor cells exposed to the steep pulse of 200 V decreased little; the concentration of Ca2+ in tumor cells exposed to the steep pulse of 250 V reduced little, too. Maybe the change of calcium burst in the tumor cells is the mechanism of apoptosis when cells are exposed to the steep pulse.
Apoptosis ; radiation effects ; Calcium ; metabolism ; Electricity ; Electromagnetic Fields ; Hepatocytes ; cytology ; pathology ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Microscopy, Confocal ; Tumor Cells, Cultured

OBJECTIVETo investigate whether 50 Hz magnetic fields (MF) can change the gene expression profile in MCF-7 cells and to screen MF responsive genes.

METHODSIn vitro cultured MCF-7 cells were continuously exposed or sham-exposed to 0.4 mT of 50 Hz MF for 24 hours. Affymetrix Human Genome Genechips (U133A) were applied to analyze gene expression profiles in MF exposed and sham-exposed MCF-7 cells and the data were processed with Genechip data analysis software MAS 5.0 and DMT 3.0. Real-time RT-PCR assay was employed to examine the differentially expressed genes.

RESULTThirty differentially expressed genes were screened with 100 % consistency change calls in the MF exposed MCF-7 cells. Six independent real-time RT-PCR analyses showed that SCNN1A, METTL3 and GPR137B were slightly but statistically significantly changed in MCF-7 cells after exposure to 50 Hz MF (P<0.05), while other analyzed genes exhibited slight up-and down-fluctuations in expressions and no increase or decrease in each gene expression reached statistical significance (P>0.05).

CONCLUSIONThe present study identified three 50 Hz MF responsive genes in MCF-7 cells and the biological consequences of expression changes in these MF responsive genes need to be further investigated.0.4 mT 50 Hz MF exposure for longer duration might induce DNA double-strand breaks in human lens epithelial cells in vitro.

Cell Line, Tumor ; DNA Breaks, Double-Stranded ; radiation effects ; Electromagnetic Fields ; Gene Expression ; radiation effects ; Gene Expression Profiling ; Humans ; Polymerase Chain Reaction ; Radio Waves ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Cells, Cultured

The killing effect on S180 cells was studied using the combination of protoporphyrin IX and focused ultrasound at the frequency of 2.2 MHz and different intensities. Cell viability was determined by trypan blue exclusion test, morphology changes were evaluated by means of scanning electron microscopy and transmission electron microscopy after ultrasonic exposure. The results indicated that protoporphyrin IX(PPIX) alone showed no significant effect on S180 cells when compared with that of control group. Ultrasound alone and ultrasound combined with PPIX groups showed some anti-tumor effect, which became more noticeable as the ultrasound intensity and PPIX concentration increased, and when the concentration of PPIX increased to 120 microM, the ultrasound combined with PPIX exerted a more significant anti-tumor effect than did the ultrasound alone in the same experiment.
Animals ; Apoptosis ; drug effects ; radiation effects ; Mice ; Mice, Inbred ICR ; Photochemotherapy ; methods ; Photosensitizing Agents ; pharmacology ; Protoporphyrins ; pharmacology ; Sarcoma 180 ; pathology ; therapy ; Sonication ; Tumor Cells, Cultured ; Ultrasonics

In cancer gene therapy, restriction of antitumor transgene expression in a radiation field by use of ionizing radiation-inducible promoters is one of the promising approaches for tumor-specific gene delivery. Although tumor suppressor protein p53 is induced by low doses (<1 Gy) of radiation, there have been only a few reports indicating potential utilization of a p53-target gene promoter, such as that of the p21 gene. This is mainly because the transiently transfected promoter of p53-target genes is not much sensitive to radiation. We examined the response of the p21 gene promoter to low-dose radiation when transduced into a human breast cancer cell line MCF-7 by use of recombinant adeno-associated virus (rAAV) vectors. It was shown that the p21 gene promoter transduced by rAAV vectors was more highly radiation-responsive than that transiently transfected by electroporation. A significant induction of the p21 gene promoter by radiation of low doses down to 0.2 Gy was observed. When cells were transduced with the p21 gene promoter-driven HSVtk gene by rAAV vector, they were significantly sensitized to repetitive treatment with low dose radiation (1 Gy) in the presence of the prodrug ganciclovir. It was therefore considered that the p21 gene promoter in combination with a rAAV vector is potentially usable for the development of a low-dose radiation-inducible vector for cancer gene therapy.
X-Rays ; Tumor Cells, Cultured ; Transgenes/*radiation effects ; Transduction, Genetic ; Promoter Regions (Genetics)/*radiation effects ; Humans ; Genetic Vectors/*radiation effects ; Gene Therapy/methods ; Electroporation/methods ; Dose-Response Relationship, Radiation ; Cyclin-Dependent Kinase Inhibitor p21/*genetics ; Adenoviridae ; 3' Untranslated Regions/physiology

In this study, we have investigated if current cancer therapeutic modalities including hyperthermia and ionizing radiation can increase the expression of NKG2D ligands in human cancer cell lines. The expressions of NKG2D ligands were induced by both heat shock and ionizing radiation in various cell lines including KM12, NCI-H23, HeLa and A375 cells with peaks at 2 h and 9 h after treatment, respectively, although inducibility of each NKG2D ligand was various depending on cell lines. During the induction of NKG2D ligands, heat shock protein 70 was induced by heat shock but not by ionizing radiation. These results were followed by increased susceptibilities to NK cell-mediated cytolysis after treatment with heat shock and ionizing radiation. These results suggest that heat shock and ionizing radiation induce NKG2D ligands and consequently might lead to increased NK cell-mediated cytotoxicity in various cancer cells.
Tumor Cells, Cultured ; Receptors, Immunologic/*metabolism ; Radiation, Ionizing ; Neoplasms/immunology/*radiotherapy/therapy ; *Ligands ; Killer Cells, Natural/*immunology ; Hyperthermia, Induced/methods ; Humans ; Hela Cells ; *Heat-Shock Response/physiology ; Heat ; HSP70 Heat-Shock Proteins/metabolism/radiation effects ; Gene Expression Regulation, Neoplastic/radiation effects ; Cytotoxicity, Immunologic/*physiology/*radiation effects ; Antigens, Surface/metabolism/radiation effects

OBJECTIVE: To investigate the apoptosis of human breast cell line MCF-7 cells induced by gemcitabine and radiation. METHODS: The MTT method was applied to study the growth inhibition of MCF-7 treated with gemcitabine, radiation, gemcitabine and radiation. The apoptosis index (AI) was analyzed by flow cytometry. The morphology of the MCF-7 cells apoptosis was observed by transmission electron microscopy. RESULTS: When MCF-7 cells were treated with gemcitabine at different concentrations for 24 h, the cell growth inhibition rate was increased in a concentration-dependent manner. The apoptotic indexes (AI) of MCF-7 of four groups by flow cytometry revealed. The AI of (R+D) group was significantly different from those of the radiation group and the gemcitabine group (P<0.05). Condensed chromation, nuclear fragmentation and apoptotic body of MCF-7 cells were found by transmission electron microscope. CONCLUSION The apoptosis of human breast cancer cell line, MCF-7 cells, could be induced by gemcitabine. Gemcitabine can significantly enhance the radiation-induced apoptosis of MCF-7 cells.
Antimetabolites, Antineoplastic ; pharmacology ; Apoptosis ; drug effects ; radiation effects ; Breast Neoplasms ; pathology ; Deoxycytidine ; analogs & derivatives ; pharmacology ; Female ; Flow Cytometry ; Humans ; Radiation ; Radiation-Sensitizing Agents ; pharmacology ; Tumor Cells, Cultured