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Abstract The aim of this study was to investigate the effect of TiO2/N-succinyl-chitosan composite (TiO2/ NSCS) photodynamic therapy (PDT), while considering the effects of various light sources on the activation of photosensitizer. The methyl thiazolyl tetrazolium assay was used to examine the cell survival rate of the cells. The results showed that glioma cell strain (U251) was the most sensitive cancer cell strain to TiO2/NSCS. When the concentration of TiO2/NSCS was between 0 and 800 μg·mL-1, there was no obvious cytotoxicity to normal liver cells (HL-7702) and U251 cells. During the PDT process, the photokilling effect of TiO2/NSCS on U251 cells under ultraviolet-A (UVA) light irradiation was stronger than that of pure TiO2, and its killing effects were positively correlated with concentration and irradiation time. In addition, both UVA and visible light could excite TiO2/ NSCS, which had significant killing effect on U251 cells. The results of acridine orange/ethidium bromide fluorescent double staining and Annexin V/propidium iodide double staining indicated that TiO2/NSCS under UVA and visible light irradiation could kill U251 cells by inducing apoptosis, and the apoptosis rate of TiO2/NSCS treatment groups was higher than that of TiO2 treatment groups. Therefore, TiO2/NSCS might be used as a potential photosensitizer in PDT.
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Radiotherapy is one of the most commonly used and effective method to treat malignant tumors in clinical practice. However, there are still some limitations including high radiotherapy doses, harmful side effects on normal tissues, and radiation resistance of tumor cells. Therefore, seeking safe and effective radiotherapy sensitizers to improve radiation sensitivity of tumor cells has been focused for a long time. Histone deacetylase inhibitors (HDACIs), as a kind of epigenetic modifiers, can regulate the sensitivity of tumor cells to ionizing radiation and ultraviolet radiation in addition to the inherent anticancer characteristics. This article reviewed the molecular mechanisms of HDACIs in enhancing radiation sensitivity and by selectively killing tumor cells.
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Objective: To investigate the killing effect of amplified natural killer (NK) cells on the gastric cancer cells, and to elucidate its mechanism. Methods: The peripheral blood mononuclear cells (PBMCs) from 15 patients with gastric cancer were extracted and isolated. The morphology of NK cells before and after amplification was observed, the percentages of NK cells before and after amplification were detected, and the amplification time of NK cells after amplification was calculated. The killing effects of NK cells on the gastric cancer cells before and after amplification were detected. The percentages of expressions of killing activating receptors NKG2D and DNAM-1 and killing inhibitory receptors KIR2DL1 and KIR3DL1 were detected by flow cytometry. Results: Before amplification, the NK cells were round, small in size and scattered in distribution. After amplification, the NK cells were increased in size and irregular in shape. The percentage of NK cells after amplification was significantly higher than that before amplification ( P<.0. 01). and the number of the NK cells after amplification was (596 ± 152) times of before amplification. When the effective target ratio was 5 : 1. the killing activity of NK cells on the gastric cancer cells after amplification was significantly higher than that before amplification (P<0.01). After amplification, the percentages of expressions of killing activating receptors NKG2D and DNAM-1 were significantly higher than those before amplification ( P<0. 01). After amplification, the percentages of expressions of killing inhibitory receptors KIR2DL1 and KIR3DL1 were significantly lower than those before amplification (P<0.05). Conclusion: The killing effect of NK cells on the gastric cancer cells after amplification is stronger than before amplification. The mechanism may be related to increasing the expressions of activated receptors and decreasing the expressions of inhibitory receptors on the surface of NK cells after amplification.
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Objective: To investigate the effect of Liuwei Dihuangwan on connexin 32 (Cx32) in hepatoma cell line CBRH7919 and its gap junction intercellular communication (GJIC), and furthermore study its mechanism of enhancing the bystander killing effect of suicide gene therapy. Method: Liuwei Dihuangwan (32 g·kg·d-1) and the same volume of normal saline were given to the rats by intragastrical administration. Blood was taken to prepare the medicated serum of Liuwei Dihuangwan and blank control serum, respectively. The hepatoma cell line CBRH7919 were treated by control serum and medicated serum of Liuwei Dihuangwan in different concentrations. There were four groups in experiment:the blank control group (volume fraction of 10%), medicated serum high dose group of Liuwei Dihuangwan (the volume fraction of 10%), medicated serum middle dose group of Liuwei Dihuangwan (the volume fraction of 5%), and medicated serum low dose group of Liuwei Dihuangwan (the volume fraction of 2.5%). The expression levels of Cx32 protein and mRNA in hepatoma cell line CBRH7919 were detected by indirect immunofluorescence assay (ⅡA) and Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR) assay. The fluorescence redistribution after photobleaching (FRAP) method was used to detect the function of GJIC of hepatoma cell line CBRH7919. Result: ① The indirect immunofluorescence assay (ⅡA) analysis indicated that as compared with the blank control group, the cx32 expression of CBRH7919 cells was up-regulated in a concentration-dependent manner in each dose group of the serum containing Liuwei Dihuangwan (PPPPConclusion: The mechanism of medicated serum of Liuwei Dihuangwan in enhancing the bystander killing effect of suicide geneis related to gap junction. Liuwei Dihuangwan may enhance the function of GJIC by increasing the localization of cx32 on the cell membrane of CBRH7919 cells and increasing the expression of cx32 mRNA and protein to achieve the synergistic action.
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Objective To explore the killing effect of dielectric barrier discharge (DBD) plasma on tumor cells and to analyze the DBD-induced apoptosis mechanism.Methods Thiazolyl blue tetrazolium bromide (MTT) assay method was used to detect the killing effect of low temperature plasma on the cytotoxicity of normal spleen leukocytes and acute promyelocytic leukemia cells (LT-12) at different doses.The changes of reactive oxygen species (ROS) level were measured after plasma treatment.The cell apoptosis rate was detected by Annexin V/PI double staining at different doses.The expression of apoptosis-related genes and proteins was detected by qRT-PCR and Western Blot.Results MTT results showed that the killing effect of plasma treatment was dose-dependent and time-dependent.The cell survival rate after 8 hours of treatment decreased from 98％ to 63％ with the dose increasing from 30 s to 240 s.The survival rate decreased from 78％ (2 h) to 39％ (24 h) after the treatment with a same dose (e.g.240 s).Annexin V/PI double staining results demonstrated that the plasma effect can induce apoptosis,and the apoptosis rate was not only positively correlated with the plasma dose,but also with the post-plasma time.The longer the post-plasma time,the higher was the apoptosis rate.The apoptotic rate of the 60 s dose treatment after 12 h was 48％ that increased to 55.3％ with the dose of 120 s.The production of reactive oxygen species (ROS) detected by flow cytometry also showed a time correlation of the plasma treatment.After the plasma treatment,the ROS level immediately increased to 1.24 times,and sharply increased to 5.39 times after 20 h post-plasma.The experimental results of qRT-PCR and Western blot showed that the expression of the genes and proteins of Caspase family and Bcl-2 family was very active at 8 to 12 h post-plasma treatment.Conclusions Low-temperature plasma can effectively kill tumor cells,and apoptosis is the main mechanism of death.The molecular mechanism of apoptosis of tumor cells induced by low temperature plasma was preliminary confirmed.
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Objective To study the anti-tumor effects of mixed cultured B16 melanoma cells supernatant.Methods The supernatant from purely cultured B16 melanoma cells or mixedly cultured B16 melanoma cells with lymphocytes and macrophages at indicated time points were collected,respectively.The chemotaxis of the two different cell supernatants was determined by Boyden room method.The activation effects towards lymphocytes of the two different supernatants were determined by CCK-8 method.Results When the cells were mixed cultured for 0.5,1,2,4,8 and 12 h,the numbers of lymphocytes to travel from the upper well to the bottom well were (1.00±0.82) × 104,(7.00±1.63) × 104,(9.50±0.58) × 104,(11.25±2.36) ×104,(17.25±1.71) × 104 and (21.50±1.29) × 104,respectively.When the cells were purely cultured for 0.5,1,2,4,8 and 12 h,the numbers of lymphocytes to travel from the upper well to the bottom well were (0.00±0.00) ×104,(0.25±0.50) × 104,(1.75±0.96) × 104,(5.25±0.96) × 104,(5.75±1.26) × 104 and (10.75±3.20) × 104,respectively.The mixed cultured group showed higher chemotaxis effects towards lymphocytes in comparison with the purely cuhured one at the same points except for 0.5 h (P ＜ 0.05).The mixed cultured group showed higher activation effects towards lymphocytes in comparison with the purely cultured at the same points except for 0.5 and 1 h (P ＜ 0.05).Each group showed higher chemotaxis and activation effects towards lymphocytes when they were cultured for 12 h than the other time points (P ＜0.05).Conclusion The supernatant from mixed cultured cells shows much higher chemotaxis and activation effects towards lymphocytes to kill tumor cells.
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Objective To evaluate the killing effect and the uptake of 125I-UdR on human lymphoma Raji and Daudi cell lines. Methods The amount of 125I-UdR in the cells and cell nuclei were determined after incubation of different time in RPMI 1640 culturing medium containing different concentrations of 125I-UdR. The killing effects of 125I-UdR on Raji and Daudi cell lines were estimated through MTT assay and cell cycle was analyzed by propidium iodide (PI) staining. Results The amounts of 125I-UdR in Raji and Dandi cells and cell nuclei were much higher than that of Na125I(P < 0.05). The amounts of 125l-UdR in Raji and Daudi cells were 14414±95 and (6916± 53.69) Bq/106 cell when the concentration was 100 kBq/ml. The amounts of Na125I were 68± 3.8 and (324±32.8) Bq/106 cell. The uptake of 125I-UdR in Raji and Daudi cells and cell nuclei increased with the 125I-UdR concentration and incubated time. The cell surviving fractions of 125I-UdR groups was much lower than that of Na125I groups (P < 0.05). When the concentration was 500 kBq/ml and incubated time was 48 hours, the Raji and Dandi cell surviving fractions of125I-UdR groups were (19.78 ± 1.39)% and (43.17 ± 2.69) % ;those of Na125I groups were (79.10 ± 1.79) % and (80.36 ± 6.12) %. The surviving fractions of 125I-UdR groups reduced with the 125I-UdR concentration. Conclusions 125I-UdR can be specially ingested by Raji and Daudi cells and incorporated into DNA, then the cells will be killed. The uptake of 125I-UdR is dose and time dependent.
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Insecticidal effects of Agnique MMF were investigated in the coastal brackish water shrimp farms in the Tan Thuan commune, Dam Doi district of Ca Mau province in 2000. The investigations were made in terracotta jars and shrimp ponds with the surface area 30m2 and 1000m2 each. Agnique MMF was found to have a high and fast killing effect on larvae of An.sundaicus at all three testing doses of 0.3ml/m2, 0.4ml/m2 and 0.5ml/m2. Especially larvae at instars of III, IV and pupae. However, the insecticide produced a low effect on Culex sitiens killing larvae of IV ins tar and only retarding larvae of I, II, III instar. The residual effect of Agnique MMF was found to be 14 days in the terracotta jars and 6 days in the ponds. In the direct observations, Agnique MMF was found to have no negative effects on rearing shrimps
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Alcools gras , Polyéthylène glycolsRésumé
Objectives:To investigate in vitro tumor killing effect of recombinant human perforin C terminal truncated 125 amino acid polypeptide (rhPFP C) and N terminal truncated 118 amino acid polypeptide (rhPFP N, 22 139aa) using liver cancer cell line SMMC 7721 as target cells. Methods:Recombinant human PFP C and PFP N peptide were expressed by E.coli in fusion form with glutathione S transferase(GST), and were purified by affinity chromatography with glutathione agarose. Liver cancer cell line SMMC 7721 was treated with fusion proteins in different concentrations for 24 h before surviving cells were measured with microscopy and colorimetric MTT assay. Results:After treatment with rhPFP C or rhPFP N, SMMC 7721 cell membrane damaged, appeared lysis. In MTT assay, optical density values in test group were significantly lower than those in control group. At concentration of 2.5 ?g/ml, the killing activity of rhPFP C and rhPFP N were 33.38% and 5.90% respectively. Conclusions:Both rhPFP C and rhPFP N showed obvious killing effect on liver cancer cell line SMMC 7721.The activity of rhPFP C was great higher than that of rhPFP N.
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Objective To study the effect of camphor oil in killing Demodex in vitro and to further analyze the killing mechanism.Methods The mites were collected with adhesive cellophane tape and randomly divided into six groups.The killing effect of camphor oil was investigated with different concentrations against Demodex in vitro.The reaction progress was pictured using Motic Images software.Results Camphor oil had better killing effect on Demodex folliculorum than on D.brevis in vitro.The death rate increased with the drug concentration and time.The most suitable and effective concentration of killing both Demodex folliculorum and D.brevis in vitro was 12.5%.After the drug was given,the mites contracted and twisted,and then relaxed and died.Conclusion Camphor oil has strong killing effect on Demodex in vitro.The main mechanism of camphor oil may be related to direct contact and neuromuscular toxicity.
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Objective:To construct an eukaryotic radiation-inducible expressing vector of the human perforin N-terminal(hPFN-N),and to investigate the distribution and the killing effect of human perforin N-terminal truncated 118 amino acid polypeptide (rhPFN-N,22-139aa) on tumor cells.Methods:The gene hPFN-N was amplified by PCR from the plasmid pcDNA3.1(+)/hPFN and an enkaryotic radiation-inducible expression vector pcDNA3.1(+)/ Egr-hPFN-N was constructed after DNA recombination.After transfecting SPC-A1 cells with this recombination vector via liposome mediation,the expression of the hPFN-N protein was detected by RT-PCR and Immunocytochemical method and the killing effect of hPFN-N protein was assessed by standard MTT chromatometry.Results:DNA sequencing and restriction endonuclease digestion analysis indicated that the eukaryotic radiation-inducible expressing vector pcDNA3.1(+)/ Egr-hPFN-N had been constructed successfully.After the recombinant plasmid being transfected into SPC-A1 cells and being irradiated by X ray,RT-PCR verified the expression of hPFN-N mRNA.The result of Immunocytochemical assay was positive and in MTT assay the killing activity of rhPFN-N on target cells was 29.2%.Conclusion:After being irradiated the hPFN-N gene is expressed on the cell membrane and the killing activity of rhPFN-N on target cells is 29.2%.