ObjectiveTo investigate the bioeffects of extremely low frequency (ELF) magnetic field (MF) (50 Hz, 400μT) and magnetic nanoparticles (MNPs) via cytotoxicity and apoptosis assays on PC12 cells.
MethodsMNPs modified by SiO2 (MNP-SiO2) were characterized by transmission electron microscopy (TEM), dynamic light scattering and hysteresis loop measurement.PC12 cells were administrated with MNP-SiO2 with or without MF exposure for 48 h. Cytotoxicity and apoptosis were evaluated with MTT assay and annexin V-FITC/PI staining, respectively. The morphology and uptake of MNP-SiO2 were determined by TEM. MF simulation was performed by Ansoft Maxwell based on the finite element method.
ResultsMNP-SiO2 were identified as~20nm (diameter) ferromagnetic particles. MNP-SiO2reduced cell viability in a dose-dependent manner. MF also reduced cell viability with increasing concentrations of MNP-SiO2. MNP-SiO2 alone did not cause apoptosis in PC12 cells; instead, the proportion of apoptotic cells increased significantly under MF exposure and increasing doses of MNP-SiO2. MNP-SiO2 could be ingested andthen cause a slight change in cellmorphology.
ConclusionCombined exposure of MF and MNP-SiO2 resulted in remarkable cytotoxicity and increased apoptosis in PC12 cells. The results suggested that MF exposure couldstrengthen the MF of MNPs, which may enhance the bioeffects of ELF MF.

INTRODUCTIONMacrophages play an important role in tumor lysis and growth inhibition. They can be activated to a tumoricidal state by a variety of agents such as IFNr, TNFa or IL2. The killing machanisms of activated macrophages have been extensively investigated[1,2]. Recently, it has been proved that antibody dependent cellular cytotoxicity (ADCC) is one of the potent arms to lyse tumor cells resistant to cytotoxic macrophages,and that the antitumorous effect of a macrophage activator is significantly augmented by the combined use of mAbs capable of inducing ADCC to tumor cells[3].

Carbon nanotubes can carry protein into cells to induce biological effects. Amino-functionalized carbon nanotubes are soluble and biocompatible, have high reactivity and low toxicity, and can help promote nerve cell growth. In this study, amino-functionalized ethylenediamine-treated multi-walled carbon nanotubes were used to prepare carbon nanotubes-nerve growth factor complexes by non-covalent grafting. The physicochemical properties, cytotoxicity to PC12 and chick embryo dorsal root ganglion, and biological activity of the carbon nanotubes-nerve growth factor complexes were investigated. The results showed that amino functionalization improved carbon nanotubes-nerve growth factor complex dispersibility, reduced their toxicity to PC12 cells, and promoted PC12 cell differentiation and chick embryo dorsal root ganglion.

Necroptosis is characterized by programmed necrotic cell death and autophagic activation and might be involved in the death process of dopaminergic neurons in Parkinson’s disease. We hypothesized that necrostatin-1 could block necroptosis and give protection to dopaminergic neurons. There is likely to be crosstalk between necroptosis and other cell death pathways, such as apoptosis and autophagy. PC12 cells were pretreated with necroststin-1 1 hour before expo-sure to 6-hydroxydopamine. We examined cell viability, mitochondrial membrane potential and expression patterns of apoptotic and necroptotic death signaling proteins. The results showed that the autophagy/lysosomal pathway is involved in the 6-hydroxydopamine-induced death pro-cess of PC12 cells. Mitochondrial disability induced overactive autophagy, increased cathepsin B expression, and diminished Bcl-2 expression. Necrostatin-1 within a certain concentration range (5–30 μM) elevated the viability of PC12 cells, stabilized mitochondrial membrane potential, inhibited excessive autophagy, reduced the expression of LC3-II and cathepsin B, and increased Bcl-2 expression. These findings suggest that necrostatin-1 exerted a protective effect against injury on dopaminergic neurons. Necrostatin-1 interacts with the apoptosis signaling pathway during this process. This pathway could be a new neuroprotective and therapeutic target in Par-kinson’s disease.

Human adipose tissues are an ideal source of stem cells. It is important to find inducers that can safely and effectively differentiate stem cells into functional neurons for clinical use. In this study, we investigate the use of Radix Angelicae Sinensis as an inducer of neuronal differentiation. Primary human adipose-derived stem cells were obtained from adult subcutaneous fatty tissue, then pre-induced with 10%Radix Angelicae Sinensis injection for 24 hours, and incubated in serum-free Dulbecco’s modified Eagle’s medium/Nutrient Mixture F-12 containing 40% Radix Angelicae Si-nensis to induce its differentiation into neuron-like cells. Butylated hydroxyanisole, a common in-ducer for neuronal differentiation, was used as the control. After human adipose-derived stem cells differentiated into neuron-like cells under the induction of Radix Angelicae Sinensis for 24 hours, the positive expression of neuron-specific enolase was lower than that of the butylated hydroxyani-sole-induced group, and the expression of glial fibril ary acidic protein was negative. After they were induced for 48 hours, the positive expression of neuron specific enolase in human adipose-derived stem cells was significantly higher than that of the butylated hydroxyanisole-induced group. Our experimental findings indicate that Radix Angelicae Sinensis can induce human adipose-derived stem celldifferentiation into neuron-like cells and produce less cytotoxicity.

OBJECTIVE:Use of cisplatin, a conventional anticancer drug, is restricted because it generates strong hepatotoxicity by accumulating in liver. Therefore its anticancer potential can only be fully exploited if its own toxicity is considerably reduced. Towards this goal, ethanolic extract of the plant, Boldo (Peumus boldus), known for its antihepatotoxic effects, was used simultaneously with cisplatin, to test its ability to reduce cisplatin’s cytotoxicity without affecting its anticancer potential. METHODS: The cytotoxicity of Boldo extract (BE) and cisplatin, administered alone and in combination, was determined in three cancer cell lines (A549, HeLa, and HepG2) and in normal liver cells (WRL-68). Drug-DNA interaction, DNA damage, cell cycle, apoptosis, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP, ΔΨ) were also studied. Hepatotoxicity and antioxidant activity levels were determined by alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and glutathione assays in mice. The cytotoxicity of related proteins was tested by Western blotting. RESULTS:Co-administration of BE and cisplatin increased viability of normal cells, but had no effect on the viability of cancer cells. Boldo protected liver from damage and normalized different antioxidant enzyme levels in vivo and also reduced ROS and re-polarized MMP in vitro. Bax and cytochrome c translocation was reduced with caspase 3 down-regulation. Further, a drug-DNA interaction study revealed that BE reduced cisplatin’s DNA-binding capacity, resulting in a reduction in DNA damage. CONCLUSION: Results indicated that a low dose of BE could be used beneifcial y in combination with cisplatin to reduce its toxicity without hampering cisplatin’s anticancer effect. These ifndings signify a potential future use of BE in cancer therapy.

Objective: To study the effects of paclitaxel on macrophage activation. Methods:Mouse macrophages were isolated by peritoneal lavage and cultured in RPMI 1640 medium according to the following groups: paclitaxel (5μmol/L) group, IFN-γ (5U/L) group, paclitaxel (5μmol/L) and IFN-γ (5U/L) combination group, and control group(without paclitaxel and IFNγ) .24 hours later, supematants were collected for nitric oxide(NO) assessment using the Griess reagent, and ttanor necrosis factor-α(TNF-α) assessment using the enzyme linked immunosorbent assay. Antibody-dependent cell-mediated cytotoxicity(ADCC) of the macrophages was assessed using the method of hemoglobin-enzyme release assay (Hb-ERA). Results: Paclitaxel induced the production of higher levels of NO(8.86 ± 1.16μmol/L) and TNF-α(120.2 ± 10.2pg/ml) ,and enhanced the ADCC of macrophages[ (20.61 + 1.13)% ]. The differences were significant compared with the control group[no NO and TNF-α detected,ADCC (15.37 + 1.93)% ](P ＜ 0.01). Paclitaxel and IFN-γ in combination induced the production of higher levels of NO(22.85 ± 0.91μmol/L) and TNF-α(358.6 ± 27 .5pg/ml), and enhanced the ADCC of macrophages[ (42.49 + 3.09) % ]. The differences were significant compared with paclitaxel or IFN-γ[NO 8.09 ± 1.13μmol/L, TNF-α1 24.8 + 9.6pg/ml, ADCC(23.32 ± 2.63) % ] alone (P＜0.01). Conclusion: These findings indicate that paclitaxel can promote NO and TNF-α production,enhance ADCC of macrophages, and induce macrophage activation. The active effects are more significant with paclitaxel and IFN-γcombination.

Cancer as an Environmental Disease:Liver Cancer in Bangladesh

Although cancer is considered a common human genetic disease,there has been no significant evidence showing that it is caused by DNA mutations.DNA mutations as drivers or passengers associated with cancer development have been described in many reports.In addition,it has been shown that environmental factors can induce cancer,and thus,cancer can be considered an environmental disease.Liver cancer has become prevalent in Bangladesh,most l ikely due to environmental pollution as the groundwater is naturally contaminated with toxic levels of arsenic.The harm caused by contamination has not been l imited to l iver cancer,as other cancer types have been reported.Moreover,in worst-case scenarios,intake of arsenic has even caused death.As arsenic is usually found in groundwater worldwide,anyone can be affected.However,intake of only a tiny amount is not considered poisonous.Bangladesh has been greatly suffering from arsenic contamination,and as a result,toxicity and cancer have become prevalent.

Acute andchronic cytotoxicity and genotoxicity induced by2,6-dichloro-1,4-benzoquinone in NIH3T3cells

Objective:This study aimed to evaluate the acute and chronic cytotoxicity and genotoxicity of 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ).Methods:NIH3T3 cells were exposed to 2,6-DCBQ for 3 and 72 h,and relative cell viability was calculated.NIH3T3 cells were treated with different concentrations of 2,6-DCBQ for 24 h.The solvent and positive controls were dimethyl sulfoxide (DMSO) and 0.5 μmol/L ethylmethylsulfone,respectively.The values of Olive tail moment were measured by comet assay.NIH3T3 cells were then simultaneously treated with 5 μg/mL cytochalasin B and different concentrations of 2,6-DCBQ.The solvent and positive controls were DMSO and 1 μmol/L mitomycin C,respectively.Micronucleus rates were calculated after 48 h.Results:The half lethal doses of 2,6-DCBQ in NIH3T3 cells were 64.93 μmol/L for 3 h and 13.46 μmol/L for 72 h.The values of Olive tail moment in the 7.5 and 10 μmol/L groups were significantly higher than those in the solvent control (P ＜0.05).Moreover,the micronucleus rates in the 10 and 15 μmol/L groups were significantly higher than those in the solvent control (P＜0.05).The results of comet assay and micronucleus test showed a dose-response relationship.Conclusion:2,6-DCBQ exhibited strong cytotoxicity and induced DNA and chromosomal damage in NIH3T3 cells.

槲皮素抑制离体人微血管内皮细胞增生

AIM: To investigate the role of quercetin (Que) in the proliferation of cultured human skin microvascular endothelial cells (MVEC). METHODS: Cell count and [methyl-3H]thymidine ([3H]TdR) uptake assay were used to measure the effect of Que in the proliferation of cultured MVEC. Cytotoxicity of Que on MVEC was also evaluated by 51Cr release assay. RESULTS: When MVEC were treated with Que, the proliferation was significantly inhibited in a time-course and dose-dependent manner. Que 5 μmol/L did not inhibit the proliferation of MVEC. When the concentration of Que increased to 20, 40, 80, and 160 μmol/L, the cell numbers per well were decreased and the inhibition rate was 12.2 %, 23.5 %, 35.3 %, and 54.1% respectively with IC50 of 138 μmol/L. The inhibitory rate of [3H]-TdR uptake was 18.7 %, 34.4 %, 48.9 %, and 62.5 % respectively (ICs0=87.5 μmol/L). 51Cr release assay showed that Que 160 μmol/L incubated with MVEC from 1 to 16 h had no clear cytotoxicity compared with control group. CONCLUSION: Que greatly inhibited the proliferation of cultured human MVEC in vitro. This effect may not be related to the cytotoxicity of Que on MVEC.