Oxidative stress mediated apoptosis induced by nickel ferrite nanoparticles in cultured A549 cells

Effect of interactions between various humic acid fractions and iron nanoparticles on the toxicity to white rot fungus

Humic acid plays an important role in controlling the toxicity of nanoparticles to organisms. However, little is known about the influence of different fractions of dissolved humic acid (DHA) from soil on the toxicity of nanoparticles to organisms. The concentration of γ-Fe₂O₃ and the exposure time affected the malondialdehyde (MDA) content, reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) activity in P. chrysosporium cells and were inversely proportional to the relative activities of the cells. P. chrysosporium was exposed to γ-Fe₂O₃ and DHA₁ for 3 h, 6 h and 12 h. Catalase (CAT) and peroxidase (POD) activities were generally higher than control. Particularly, under the influence of 50 mg/L DHA₁ and different concentrations of γ-Fe₂O₃ (10 and 50 mg/L), the CAT and POD activities were higher than those of cells exposed to γ-Fe₂O₃ alone. Conversely, both activities of P. chrysosporium exposed to DHA₄ combined with γ-Fe₂O₃ for 12 h were lower than those of cells exposed to γ-Fe₂O₃ alone and gradually decreased with increasing DHA₄ concentration (0, 10 and 50 mg/L). The μ-XAFS normalized spectrum indicated that Fe³⁺ entering the cells tended to transform into Fe²⁺ as the stress time prolonged. TEM analysis confirmed the toxicity of high concentrations of γ-Fe₂O₃ to P. chrysosporium. The comet assay showed that DHA₄ in soil enhanced the toxicity of γ-Fe₂O₃ to P. chrysosporium more than DHA₁ did. Namely, compared to DHA₁, DHA₄ made it easier for nano-Fe₂O₃ to enter P. chrysosporium cells, causing more toxicity of γ-Fe₂O₃ to P. chrysosporium.

Influence of silica nanoparticles on cadmium-induced cytotoxicity, oxidative stress, and apoptosis in human liver HepG2 cells

Extensive application of amorphous silica nanoparticles (Si NPs) and ubiquitous cadmium (Cd) may increase their chances of coexposure to humans. Studies on combined effects of Si NPs and Cd in human cells are very limited. We investigated the potential mechanism of toxicity caused by coexposure of amorphous Si NPs and Cd in human liver (HepG2) cells. Results showed that Si NPs were not toxic to HepG2. However, Cd induced significant toxicity in HepG2 cells. Interestingly, we observed that a noncytotoxic concentration of Si NPs potentiated the cytotoxicity of Cd in HepG2 cells. We further noticed that coexposure of Si NPs and Cd augmented oxidative stress evidenced by the generation of oxidants (reactive oxygen species, hydrogen peroxide, and lipid peroxidation) and depletion of antioxidants (glutathione level and antioxidant enzyme activity). Coexposure of Si NPs and Cd also augmented mitochondria-mediated apoptosis in HepG2 cells indicated by altered regulation of apoptotic genes (p53, bax, bcl-2, caspase-3, and caspase-9) along with reduced mitochondrial membrane potential. Interaction data indicated that Si NPs facilitate the cellular uptake of Cd due to its strong adsorption on the surface of Si NPs. Hence, Si NPs increased the bioaccumulation and toxicity of Cd in HepG2 cells. This study warrants further research to explore the potential mechanisms of combined toxicity of Si NPs and Cd in animal models.

TiO2 nanoparticles potentiated the cytotoxicity, oxidative stress and apoptosis response of cadmium in two different human cells

Widespread application of titanium dioxide nanoparticles (nTiO₂) and ubiquitous cadmium (Cd) pollution may increase their chance of co-existence in the natural environment. Toxicological information on co-exposure of nTiO₂ and Cd in mammalian models is largely lacking. Hence, we studied the combined effects of nTiO₂ and Cd in human liver (HepG2) and breast cancer (MCF-7) cells. We observed that nTiO₂ did not produce toxicity to HepG2 and MCF-7 cells. However, moderate concentration of Cd exposure caused cytotoxicity to both cells. Interestingly, non-cytotoxic concentration of nTiO₂ effectively enhanced the oxidative stress response of Cd indicated by pro-oxidants generation (reactive oxygen species, hydrogen peroxide, and lipid peroxidation) and antioxidants depletion (glutathione level and glutathione reductase, superoxide dismutase, and catalase enzymes). Moreover, nTiO₂ potentiated the Cd-induced apoptosis in both cells suggested by altered expression of p53, bax, and bcl-2 genes along with low mitochondrial membrane potential. Cellular uptake results demonstrated that nTiO₂ facilitates the internalization of Cd into the cells. Overall, this study demonstrated that non-cytotoxic concentration of nTiO₂ enhanced the toxicological potential of Cd in human cells. Therefore, more attention should be paid on the combine effects of nTiO₂ and Cd on human health.

Alleviating effects of reduced graphene oxide against lead-induced cytotoxicity and oxidative stress in human alveolar epithelial (A549) cells

Broad application of reduced graphene oxide (rGO) and ubiquitous lead (Pb) pollution may increase the possibility of combined exposure of humans. Information on the combined effects of rGO and Pb in human cells is scarce. This work was designed to explore the potential effects of rGO on Pb-induced toxicity in human alveolar epithelial (A549) cells. Prepared rGO was polycrystalline in nature. The formation of a few layers of visible creases and silky morphology due to high aspect ratio was confirmed. Low level (25 μg/mL) of rGO was not toxic to A549 cells. However, Pb exposure (25 μg/mL) induced cell viability reduction, lactate dehydrogenase enzyme leakage with rounded morphology in A549 cells. Remarkably, Pb-induced cytotoxicity was significantly mitigated by rGO co-exposure. Pb-induced mitochondrial membrane potential loss, cell cycle arrest and higher activity of caspase-3 and -9 enzymes were also alleviated by rGO co-exposure. Moreover, we observed that Pb exposure causes generation of pro-oxidants (e.g., reactive oxygen species, hydrogen peroxide and lipid peroxidation) and antioxidant depletion (e.g., glutathione and antioxidant enzymes). In addition, the effects of Pb on pro-oxidant and antioxidant markers were significantly reverted by GO co-exposure. Inductively coupled plasma-mass spectrometry suggested that due to the adsorption of Pb on rGO sheets, accessibility of Pb ions for A549 cells was limited. Hence, rGO reduced the toxicity of Pb in A549 cells. This research warrants further study to work on detailed underlying mechanisms of the mitigating effects of rGO against Pb-induced toxicity on a molecular level.

Temperature-controlled magnetic nanoparticles hyperthermia inhibits primary tumor growth and metastases dissemination

Magnetic hyperthermia (MHT) is a promising approach for cancer therapy. However, a systematic MHT characterization as function of temperature on the therapeutic efficiency is barely analyzed. Here, we first perform comparative temperature-dependent analysis of the cobalt ferrite nanoparticles-mediated MHT effectiveness in two murine tumors models - breast (4T1) and colon (CT26) cancer in vitro and in vivo. The overall MHT killing capacity in vitro increased with the temperature and CT26 cells were more sensitive than 4T1 when heated to 43 °C. Well in line with the in vitro data, such heating cured non-metastatic CT26 tumors in vivo, while only inhibiting metastatic 4T1 tumor growth without improving the overall survival. High-temperature MHT (>47 °C) resulted in complete 4T1 primary tumor clearance, 25-40% long-term survival rates, and, importantly, more effective prevention of metastasis comparing to surgical extraction. Thus, the specific MHT temperature must be defined for each tumor individually to ensure a successful antitumor therapy.

Optically active neodymium hydroxide surface-functionalized mesoporous silica micro-cocoons for biomedical applications

Neodymium hydroxide (Nd(OH)₃)-surface modified mesoporous silica micro-cocoon microstructures were prepared using a facile single-step sol-gel chemical process. XRD revealed the semi-crystalline nature of the as-prepared materials. TEM and SEM micrographs exhibited highly monodisperse, non-aggregated, typical ordered mesoporous, and irregular sized cocoon-shaped micro-structures with a narrow size distribution. Optical properties, that were examined in the aqueous media, revealed a high colloidal stability and the formation of a semi-transparent colloidal solution. The colloidal solution of Nd(OH)₃-surface functionalized micro-structures revealed well characteristics absorption bands of Nd³⁺ ions in the visible region. thus validating the successful coating of SiO₂@Nd(OH)₃ layer over the surface silica forming core-shell structures. Zeta potential, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) bromide, and neutral red uptake assays were applied in a dose-dependent manner to investigate the biocompatibility and toxic potential of the designed cocoon-shaped microstructures. Both the assays and the high zeta potential value demonstrated good cell viability even at high concentrations and hydrophilic conditions, indicating excellent biocompatibility and non-toxicity. These highly hydrophilic, optically active, mesoporous, biocompatible, and non-toxic cocoon-shaped microstructures could be potentially suitable candidates for optical bio-probes and drug delivery applications.

The Effects of (11R)-13-(6-Nitroindazole)-11,13-Dihydroludartin on Human Prostate Carcinoma Cells and Mouse Tumor Xenografts

BACKGROUND This study aimed to investigate the effects of the 6-nitroindazole compound and amino analog of ludartin, (11R)-13-(6-nitroindazole)-11,13-dihydroludartin (NDHL), on human prostate carcinoma cells in vitro and in mouse tumor xenografts in vivo. MATERIAL AND METHODS DU-145 and LNCaP human prostate carcinoma cells were cultured with increasing concentrations of NDHL. Cell viability was measured using the MTT assay, and cell apoptosis was measured by fluorescence flow cytometry. Mouse tumor xenografts were created by implanting 2×10⁶ of DU-145 cells subcutaneously in the left flank. On the second day following DU-145 cell implantation, the mice in the treatment groups were injected intraperitoneally with 2, 5, and 10 mg/kg of NDHL. RESULTS Treatment of DU-145 and LNCaP cells with NDHL (range, 2.5-20.0 μM) significantly reduced cell proliferation in vitro (P<0.05). The proliferation rate of DU-145 and LNCaP cells was reduced to 27% and 24%, respectively, following treatment with 20.0 μM of NDHL. Treatment with NDHL significantly increased cell apoptosis and the formation of reactive oxygen species (ROS) formation in DU-145 cells at 48 h (P<0.05). NDHL significantly increased the proportion of DU-145 cells in the G1 phase of the cell cycle and significantly increased the expression of cyclin D1 and p21 (P<0.05). Treatment of the mice in the xenograft tumor model with NDHL significantly increased survival and suppressed tumor growth (P<0.02). CONCLUSIONS NDHL inhibited cell proliferation, increased apoptosis, and caused cell cycle arrest in human prostate carcinoma cells in vitro and inhibited mouse tumor xenograft growth in vivo.

Investigation of Cytotoxicity, Apoptosis, and Oxidative Stress Response of Fe3O4-RGO Nanocomposites in Human Liver HepG2 cells

Iron oxide–reduced graphene oxide (Fe₃O₄-RGO) nanocomposites have attracted enormous interest in the biomedical field. However, studies on biological response of Fe₃O₄-RGO nanocomposites at the cellular and molecular level are scarce. This study was designed to synthesize, characterize, and explore the cytotoxicity of Fe₃O₄-RGO nanocomposites in human liver (HepG2) cells. Potential mechanisms of cytotoxicity of Fe₃O₄-RGO nanocomposites were further explored through oxidative stress. Prepared samples were characterized by UV-visible spectrophotometer, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy dispersive spectroscopy. The results demonstrated that RGO induce dose-dependent cytotoxicity in HepG2 cells. However, Fe₃O₄-RGO nanocomposites were not toxic. We further noted that RGO induce apoptosis in HepG2 cells, as evidenced by mitochondrial membrane potential loss, higher caspase-3 enzyme activity, and cell cycle arrest. On the other hand, Fe₃O₄-RGO nanocomposites did not alter these apoptotic parameters. Moreover, we observed that RGO increases intracellular reactive oxygen species and hydrogen peroxide while decrease antioxidant glutathione. Again, Fe₃O₄-RGO nanocomposites did not exert oxidative stress. Altogether, we found that RGO significantly induced cytotoxicity, apoptosis and oxidative stress. However, Fe₃O₄-RGO nanocomposites showed good biocompatibility to HepG2 cells. This study warrants further research to investigate the biological response of Fe₃O₄-RGO nanocomposites at the gene and molecular level.

Heavy metals contaminating the environment of a progressive supranuclear palsy cluster induce tau accumulation and cell death in cultured neurons

Progressive supranuclear palsy (PSP) is a neurodegenerative disorder characterized by the presence of intracellular aggregates of tau protein and neuronal loss leading to cognitive and motor impairment. Occurrence is mostly sporadic, but rare family clusters have been described. Although the etiopathology of PSP is unknown, mutations in the MAPT/tau gene and exposure to environmental toxins can increase the risk of PSP. Here, we used cell models to investigate the potential neurotoxic effects of heavy metals enriched in a highly industrialized region in France with a cluster of sporadic PSP cases. We found that iPSC-derived iNeurons from a MAPT mutation carrier tend to be more sensitive to cell death induced by chromium (Cr) and nickel (Ni) exposure than an isogenic control line. We hypothesize that genetic variations may predispose to neurodegeneration induced by those heavy metals. Furthermore, using an SH-SY5Y neuroblastoma cell line, we showed that both heavy metals induce cell death by an apoptotic mechanism. Interestingly, Cr and Ni treatments increased total and phosphorylated tau levels in both cell types, implicating Cr and Ni exposure in tau pathology. Overall, this study suggests that chromium and nickel could contribute to the pathophysiology of tauopathies such as PSP by promoting tau accumulation and neuronal cell death.

3,6-diazabicyclo[3.3.1]heptanes Induces Apoptosis and Arrests Cell Cycle in Prostate Cancer Cells

Background

Prostate cancer, non-cutaneous malignant tumor, is the second common cause of cancer related mortalities in American men and is responsible for 13% of deaths related to cancer. The present study investigated the anti-cancer effects of 3,6-diazabicyclo[3.3.1]heptane on LNCaP and PC3 prostate cancer cells in vitro and on tumor growth in vivo in BALB/C nude mice.

Material/Methods

Reduction of cell viability by 3,6-diazabicyclo[3.3.1]heptane was evaluated by sulphorhodamine-B staining and apoptosis onset using annexin V and propidium iodide (PI) staining. The 2′,7′-dichlorofluorescein-diacetate stain was used for assessment of reactive oxygen species (ROS) formation while as western blotting for analysis of protein expression.

Results

The viability of LNCaP and PC3 cells was reduced significantly (P<0.05) by 3,6-diazabicyclo[3.3.1]heptane in dose-based manner. At 30 μM of 3,6-diazabicyclo[3.3.1]heptane the viability of LNCaP and PC3 cells was reduced to 32 and 28%, respectively. The 3,6-diazabicyclo[3.3.1]heptane treatment increased apoptosis in LNCaP cells to 43.31% at 30 μM. The cell cycle in LNCaP cells was arrested in G1 phase on treatment with 3,6-diazabicyclo[3.3.1]heptane. The expression of cyclin D1 and p21 proteins was significantly increased by 3,6-diazabicyclo[3.3.1]heptane in LNCaP and PC3 cells. The growth of prostate tumor was also suppressed in vivo in mice by 3,6-diazabicyclo[3.3.1]heptane treatment.

Conclusions

In summary, the study demonstrated that LNCaP and PC3 prostate cancer cell viability is suppressed by 3,6-diazabicyclo[3.3.1]heptane treatment. The suppression of prostate cancer cell viability by 3,6-diazabicyclo[3.3.1]heptane involves apoptosis induction, cell cycle arrest and upregulation of p21 expression. Therefore, 3,6-diazabicyclo[3.3.1]heptane can be a potential chemotherapeutic agent for prostate cancer.

Biocompatibility assessment of Fe3O4 nanoparticles using Saccharomyces cerevisiae as a model organism

Using Saccharomyces cerevisiae as an experimental model, the potential toxicological effects of Fe₃O₄ nanoparticles (Fe₃O₄-NPs) were investigated following exposure to 0-600 mg/L for 24 h. Results revealed that cell proliferation was significantly inhibited by Fe₃O₄-NPs with an IC₅₀ value of 326.66 mg/L. Mortality showed a concentration-dependent increase, and the highest concentration in this study (600 mg/L) resulted in 22.30% mortality. In addition, Effects on proliferation and mortality were accounted for Fe₃O₄-NPs rather than iron ion released from Fe₃O₄-NPs. Scanning and transmission electron microscope observation showed that Fe₃O₄-NPs extensively attached on the cell surfaces, causing cells to deform and shrink. Moreover, Fe₃O₄-NPs could be internalized in S. cerevisiae cells via endocytosis and then be distributed in cytoplasm and vesicles. The data of uptake kinetics demonstrated that the maximal accumulation (4.898 mg/g) was reached at 15 h. Besides, percentage of late apoptosis/necrosis was observably increased (p < 0.01) at 600 mg/L (15.80%), and the expression levels of apoptosis-related genes (SOD, Yca1 and Nuc1) were dramatically increased following exposure to Fe₃O₄-NPs for 24 h. As expected, mitochondrial transmembrane potential was significantly decreased (p < 0.01) at 50-600 mg/L, and biomarkers of oxidative stress (ROS, CAT and SOD) were also markedly changed following exposure. Altogether, the combined results so far indicated Fe₃O₄-NPs could induce S. cerevisiae cell apoptosis that mediated by mitochondrial impairment and oxidative stress.

Neurotoxicity mediated by oxidative stress caused by titanium dioxide nanoparticles in human neuroblastoma (SH-SY5Y) cells

BACKGROUND

Titanium is widely used in biomedicine. Due to biotribocorrosion, titanium dioxide (TiO₂) nanoparticles (NPs) can be released from the titanium implant surface, enter the systemic circulation, and migrate to various organs and tissues including the brain. A previous study showed that 5 nm TiO₂ NPs reached the highest concentration in the brain. Even though TiO₂ NPs are believed to possess low toxicity, little is known about their neurotoxic effects. The aim of the study was to evaluate in vitro the effects of 5 nm TiO₂ NPs on a human neuroblastoma (SH-SY5Y) cell line.

METHODS

Cell cultures were divided into non-exposed and exposed to TiO₂ NPs for 24 h. The following were evaluated: reactive oxygen species (ROS) generation, apoptosis, cellular antioxidant response, endoplasmic reticulum stress and autophagy.

RESULTS

Exposure to TiO₂ NPs induced ROS generation in a dose dependent manner, with values reaching up to 10 fold those of controls (p < 0.001). Nrf2 nuclear localization and autophagy, also increased in a dose dependent manner. Apoptosis increased by 4- to 10-fold compared to the control group, depending on the dose employed.

CONCLUSIONS

Our results show that TiO₂ NPs cause ROS increase, induction of ER stress, Nrf2 cytoplasmic translocation to the nucleus and apoptosis. Thus, neuroblastoma cell response to TiO₂ NPs may be associated with an imbalance of the oxidative metabolism where endoplasmic reticulum-mediated signal pathway seems to be the main neurotoxic mechanism.

Toxicity Mechanism of Gadolinium Oxide Nanoparticles and Gadolinium Ions in Human Breast Cancer Cells

Background:

Due to the potential advantages of Gadolinium Nanoparticles (NPs) over gadolinium elements, gadolinium based NPs are currently being explored in the field of MRI. Either in elemental form or nanoparticulate form, gadolinium toxicity is believed to occur due to the deposition of gadolinium ion (designated as Gd3+ ion or simply G ion).

Objective:

There is a serious lack of literature on the mechanisms of toxicity caused by either gadolinium-based NPs or ions. Breast cancer tumors are often subjected to MRIs, therefore, human breast cancer (MCF-7) cells could serve as an appropriate in vitro model for the study of Gadolinium Oxide (GO) NP and G ion.

Methods:

Cytotoxicity and oxidative damage was determined by quantifying cell viability, cell membrane damage, and Reactive Oxygen Species (ROS). Intracellular Glutathione (GSH) was measured along with cellular Total Antioxidant Capacity (TAC). Autophagy was determined by using Monodansylcadaverine (MDC) and Lysotracker Red (LTR) dyes in tandem. Mitochondrial Membrane Potential (MMP) was measured by JC-1 fluorescence. Physicochemical properties of GO NPs were characterized by field emission transmission electron microscopy, X-ray diffraction, and energy dispersive spectrum.

Results:

A time- and concentration-dependent toxicity and oxidative damage was observed due to GO NPs and G ions. Bax/Bcl2 ratios, FITC-7AAD double staining, and cell membrane blebbing in phase-contrast images all suggested different modes of cell death induced by NPs and ions.

Conclusion:

In summary, cell death induced by GO NPs with high aspect ratio favored apoptosis-independent cell death, whereas G ions favored apoptosis-dependent cell death.

Evaluation of the Cytotoxicity and Oxidative Stress Response of CeO2-RGO Nanocomposites in Human Lung Epithelial A549 Cells

Graphene-based nanocomposites have attracted enormous interest in nanomedicine and environmental remediation, owing to their unique characteristics. The increased production and widespread application of these nanocomposites might raise concern about their adverse health effects. In this study, for the first time, we examine the cytotoxicity and oxidative stress response of a relatively new nanocomposite of cerium oxide-reduced graphene oxide (CeO₂-RGO) in human lung epithelial (A549) cells. CeO₂-RGO nanocomposites and RGO were prepared by a simple hydrothermal method and characterized by relevant analytical techniques. Cytotoxicity data have shown that RGO significantly induces toxicity in A549 cells, evident by cell viability reduction, membrane damage, cell cycle arrest, and mitochondrial membrane potential loss. However, CeO₂-RGO nanocomposites did not cause statistically significant toxicity as compared to a control. We further observed that RGO significantly induces reactive oxygen species generation and reduces glutathione levels. However, CeO₂-RGO nanocomposites did not induce oxidative stress in A549 cells. Interestingly, we observed that CeO₂ nanoparticles (NPs) alone significantly increase glutathione (GSH) levels in A549 cells as compared to a control. The GSH replenishing potential of CeO₂ nanoparticles could be one of the possible reasons for the biocompatible nature of CeO₂-RGO nanocomposites. Our data warrant further and more advanced research to explore the biocompatibility/safety mechanisms of CeO₂-RGO nanocomposites in different cell lines and animal models.

7-H-Pyrrolo[2,3-d]pyrimidine derivative acts as promising agent for gastric cancer treatment by inducing cell death

In the present study effect of 7-H-pyrrolo[2,3-d]pyrimidine derivative (7-HPPD) on viability of MKN28 and MKN74 gastric cancer cells was investigated. There was no significant change in GES-1 cell viability on treatment with 7-HPPD for 48 h. MKN28 and MKN74 cell viability was reduced to 21 and 23%, respectively, on treatment with 7-HPPD at concentration of 50 µM. Hoechst 33342 staining showed that the cells treated with 7-HPPD showed condensation of chromatin material, presence of apoptotic bodies and intense blue fluorescence. Treatment of MKN28 and MKN74 cells with 7-HPPD markedly increased the release of LDH. Z-VAD-FMK prevented 7-HPPD-induced suppression of MKN28 and MKN74 cell viability. Exposure to 15, 20, 25, 30 and 50 µM concentrations of 7-HPPD caused concentration-based increase in caspase-8, -9, -3 and cleaved PARP. A significant increase in ROS production was caused by 7-HPPD in MKN28 and MKN74 cells. Increasing the concentration of 7-HPPD from 10 to 50 µM did not increase the expression of RIP3 protein. In summary, 7-HPPD suppresses gastric cancer cell growth by inducing apoptosis through increase in caspase expression and ROS production. Consequently, 7-HPPD may be used for the development of treatment strategy for gastric cancer.

Inhibition of Lung Cancer Proliferation by Wogonin is Associated with Activation of Apoptosis and Generation of Reactive Oxygen Species

Background

Lung cancer has a very high incidence rate and is one of the commonly diagnosed tumors in developed countries.

Aims

To investigate the effect of wogonin on A549 and A427 lung cancer cells and explore the mechanism involved.

Study Design

Cell study.

Methods

The cytotoxicity effect of wogonin on A549 and A427 lung cancer and BEAS-2B cells was assessed by MTT assay. The onset of apoptosis was assessed by flow cytometry using Annexin V FITC/PI staining. Western blotting was used for the determination of changes in apoptotic protein expression.

Results

Wogonin treatment exhibited cytotoxicity effect selectively on A549 and A427 cells without affecting BEAS-2B normal lung cells. The viability of A549 and A427 cells was reduced to 31% and 34%, respectively, on treatment with 50 μM of wogonin; however, there was no significant reduction in BEAS-2B cell viability on treatment with the same concentration of it. Moreover, the percentage of apoptotic A427 cells showed a significant (p<0.049) increase on treatment with wogonin. Furthermore, the treatment led to a marked increase in the activation of caspase 3/8/9 and the generation of reactive oxygen species (ROS) at 72 h in A427 cells. Digital tomosynthesis studies showed a marked reduction in tumor development on treatment with wogonin.

Conclusion

Wogonin treatment specifically exhibits a cytotoxic effect on lung cancer cells and this effect is associated with activation of apoptosis and generation of reactive oxygen species.

Inhibition of Proliferation of SGC7901 and BGC823 Human Gastric Cancer Cells by Ursolic Acid Occurs Through a Caspase-Dependent Apoptotic Pathway

BACKGROUND Worldwide, gastric cancer is one of the most common malignant tumors. Ursolic acid is a plant metabolite and pentacyclic triterpenoid used in traditional Chinese medicine. This study aimed to investigate the effects of ursolic acid the growth and apoptosis of SGC7901 and BGC823 human gastric cancer cells in vitro. MATERIAL AND METHODS SGC7901 and BGC823 human gastric cancer cells and normal GES-1 gastric epithelial cells were cultured with increasing doses of ursolic acid at 50, 60, and 100 µM. Cell viability and proliferation were assessed using an MTT assay. Flow cytometry was used to assess cell apoptosis. Western blot was used to measure procaspase-8, procaspase-9, procaspase-3, and cleaved poly (ADP-ribose) polymerase (PARP) expression. The expression of receptor interaction protein 3 (RIP3) was examined by Western blot and reverse transcription polymerase chain reaction (RT-PCR). Morphological changes in the gastric cancer cells were determined using Hoechst 33342 staining following ursolic acid treatment. RESULTS Ursolic acid inhibited the viability of SGC7901 and BGC823 cells but not GES-1 cells. Ursolic acid treatment significantly induced apoptosis in SGC7901 and BGC823 cells when compared with GES-1 cells (P<0.05), and significantly increased the activation of caspase-3, caspase-8, caspase-9, poly ADPribose polymerase (PARP), and the production of reactive oxygen species (ROS). Treatment of SGC7901 and BGC823 cells with ursolic acid for 72 h did not induce necroptosis. CONCLUSIONS Ursolic acid inhibited the proliferation of SGC7901 and BGC823 human gastric cancer cells in vitro through a caspase-dependent apoptotic pathway.

Co-Exposure to SiO2 Nanoparticles and Arsenic Induced Augmentation of Oxidative Stress and Mitochondria-Dependent Apoptosis in Human Cells

Widespread application of silica nanoparticles (nSiO₂) and ubiquitous metalloid arsenic (As) may increase their chances of co-exposure to human beings in daily life. Nonetheless, studies on combined effects of nSiO₂ and As in human cells are lacking. We investigated the co-exposure effects of nSiO₂ and As in human liver (HepG2) and human fibroblast (HT1080) cells. Results showed that nSiO₂ did not cause cytotoxicity. However, exposure of As caused oxidative stress and apoptosis in both types of cells. Interesting results were that co-exposure of a non-cytotoxic concentration of nSiO₂ significantly augmented the As induced toxicity in both cells. Intracellular level of As was higher in the co-exposure group (nSiO₂ + As) than the As group alone, suggesting that nSiO₂ facilitates the cellular uptake of As. Co-exposure of nSiO₂ and As potentiated oxidative stress indicated by pro-oxidants generation (reactive oxygen species, hydrogen peroxide and lipid peroxidation) and antioxidants depletion (glutathione level, and glutathione reductase, superoxide dismutase and catalase activities). In addition, co-exposure of nSiO₂ and As also potentiated mitochondria-mediated apoptosis suggested by increased expression of p53, bax, caspase-3 and caspase-9 genes (pro-apoptotic) and decreased expression of bcl-2 gene (anti-apoptotic) along with depleted mitochondrial membrane potential. To the best of our knowledge, this is the first study showing that co-exposure of nSiO₂ and As induced augmentation of oxidative stress and mitochondria-mediated apoptosis in HepG2 and HT1080 cells. Hence, careful attention is required for human health assessment following combined exposure to nSiO₂ and As.

Unravelling the molecular mechanisms of nickel in woodlice

During the last few years, there has been an alarming increase in the amount of nickel (Ni) being released into the environment, primarily due to its use in the production of stainless steel but also from other sources such as batteries manufacturing and consequent disposal. The established biotic ligand models provide precise estimates for Ni bioavailability, in contrast, studies describing the mechanisms underpinning toxicological effect of Ni are scarce. This study exploits RNA-seq to determine the transcriptomic responses of isopods using Porcellionides pruinosus as an example of a terrestrial metal-resistant woodlouse. Furthermore, the recently proposed model for Ni adverse outcome pathways (Ni-AOP) presents an unprecedented opportunity to fit isopod responses to Ni toxicity and define Porcellionides pruinosus as a metalomic model. Prior to this study, P. pruinosus represented an important environmental sentinel, though lacking genetic/omic data. The reference transcriptome generated here thus represents a major advance and a novel resource. A detailed annotation of the transcripts obtained is presented together with the homology to genes/gene products from Metazoan and Arthropoda phylum, Gene Ontology (GO) classification, clusters of orthologous groups (COG) and assignment to KEGG metabolic pathways. The differential gene expression comparison was determined in response to nickel (Ni) exposure and used to derive the enriched pathways and processes. It revealed a significant impact on ion trafficking and storage, oxidative stress, neurotoxicity, reproduction impairment, genetics and epigenetics. Many of the processes observed support the current Ni-AOP although the data highlights that the current model can be improved by including epigenetic endpoints, which represents key chronic risks under a scenario of Ni toxicity.

Toxicity response of highly colloidal, bioactive, monodisperse SiO2@ Pr(OH)3 hollow microspheres

In a facile synthesis, highly colloidal, bioactive Pr(OH)₃-encapsulated silica microspheres (PSMSs) with an average diameter of 500-700 nm were successfully prepared via a sol-gel process followed by heat treatment. The phase formation, morphology, surface and optical properties of the as-synthesized PSMSs were characterized by various techniques including X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), transmission electron microscope (TEM), N₂-adsorption-desorption, energy dispersive X-ray (EDX) analysis, Fourier transform infrared (FTIR) and UV/vis spectroscopy. The PSMSs were semi-amorphous or ultra-small in size, highly dispersible in water, mesoporous, irregular in size and spherical in shape. The SEM images show a well-ordered broad nanoporous structure which is preserved after coating with Pr(OH)₃ molecules, demonstrating interaction between the optically active Pr³⁺ ion and silanol (Si-OH) groups via hydrogen bonding. Optical spectra show well-resolved weak intensity 4f-4f absorption transitions in the visible region of the Pr³⁺ ion, indicating successful grafting of the Pr(OH)₃ layer. Toxicity was measured by MTT and NRU assays to determine potential toxicity. Cell viability was suppressed with increasing dosage of PSMSs, but showed greater than 55% cell viability at a concentration of 200 μg/mL, resulting in low toxicity. Due to its high aqueous dispersibility, optical activity, excellent biocompatibility and low toxic nature, it could be a favorable material for biomedical and drug delivery applications.

An In Vitro Study on the Cytotoxicity and Genotoxicity of Silver Sulfide Quantum Dots Coated with Meso-2,3-dimercaptosuccinic Acid

Objectives

Silver sulfide (Ag₂S) quantum dots (QDs) are highly promising nanomaterials in bioimaging systems due to their high activities for both imaging and drug/gene delivery. There is insufficient research on the toxicity of Ag₂S QDs coated with meso-2,3-dimercaptosuccinic acid (DMSA). In this study, we aimed to determine the cytotoxicity of Ag₂S QDs coated with DMSA in Chinese hamster lung fibroblast (V79) cells over a wide range of concentrations (5-2000 μg/mL).

Materials and Methods

Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and neutral red uptake (NRU) assays. The genotoxic and apoptotic effects of DMSA/Ag₂S QDs were also assessed by comet assay and real-time polymerase chain reaction technique, respectively.

Results

Cell viability was 54.0±4.8% and 65.7±4.1% at the highest dose (2000 μg/mL) of Ag₂S QDs using the MTT and NRU assays, respectively. Although cell viability decreased above 400 μg/mL (MTT assay) and 800 μg/mL (NRU assay), DNA damage was not induced by DMSA/Ag₂S QDs at the studied concentrations. The mRNA expression levels of p53, caspase-3, caspase-9, Bax, Bcl-2, and survivin genes were altered in the cells exposed to 500 and 1000 μg/mL DMSA/Ag₂S QDs.

Conclusion

The cytotoxic effects of DMSA/Ag₂S QDs may occur at high doses through the apoptotic pathways. However, DMSA/Ag₂S QDs appear to be biocompatible at low doses, making them well suited for cell labeling applications.

Epidemiology of Pancreatic Cancer: Global Trends, Etiology and Risk Factors

Pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide. However, its toll is higher in more developed countries. Reasons for vast differences in mortality rates of pancreatic cancer are not completely clear yet, but it may be due to lack of appropriate diagnosis, treatment and cataloging of cancer cases. Because patients seldom exhibit symptoms until an advanced stage of the disease, pancreatic cancer remains one of the most lethal malignant neoplasms that caused 432,242 new deaths in 2018 (GLOBOCAN 2018 estimates). Globally, 458,918 new cases of pancreatic cancer have been reported in 2018, and 355,317 new cases are estimated to occur until 2040. Despite advancements in the detection and management of pancreatic cancer, the 5-year survival rate still stands at 9% only. To date, the causes of pancreatic carcinoma are still insufficiently known, although certain risk factors have been identified, such as tobacco smoking, diabetes mellitus, obesity, dietary factors, alcohol abuse, age, ethnicity, family history and genetic factors, Helicobacter pylori infection, non-O blood group and chronic pancreatitis. In general population, screening of large groups is not considered useful to detect the disease at its early stage, although newer techniques and the screening of tightly targeted groups (especially of those with family history), are being evaluated. Primary prevention is considered of utmost importance. Up-to-date statistics on pancreatic cancer occurrence and outcome along with a better understanding of the etiology and identifying the causative risk factors are essential for the primary prevention of this disease.

In vitro genotoxicity assessment of nickel(II) oxide nanoparticles on lymphocytes of human peripheral blood

The current study was intended to elucidate the cytotoxicity, genotoxicity ability of nickel oxide (NiO) nanoparticles (NPs) and assessment of preliminary mechanism of the toxicity. Characterization studies showed that NiO-NPs have a particle size of 17.94 (±3.48) nm. The particle size of the NPs obtained by dynamic light scattering method in Milli-Q and RPMI 1640 media was 189.9 (±17.1) and 285.9 (±19.6) nm, respectively. The IC₅₀ concentration for NiO-NPs after 24 hours of treatment was estimated as 23.58 μg/mL. Comet and cytokinesis-block micronucleus assays revealed a significant dose- and time-dependent genotoxic potential of NiO-NPs. Morphological assessment of the lymphocytes upon exposure to NiO-NPs showed that the mechanism of toxicity was apoptosis. Reactive oxygen species analysis and lipid peroxidation patterns were aligned with the cytotoxicity and genotoxicity endpoints. Thus, the preliminary mechanism of NiO-NPs for cytotoxicity on lymphocytes was assumed to be oxidative stress-mediated apoptosis and DNA damage. Furthermore, these NiO-NPs are considered a potentially hazardous substance at environmentally significant levels. Further investigations are suggested to understand the immunotoxic effects of NiO-NPs.

In vitro toxicity assessment of zinc and nickel ferrite nanoparticles in human erythrocytes and peripheral blood mononuclear cell

Ferrite nanoparticles (NPs) have gained attention in biomedicine due to their many potential applications, such as targeted drug delivery, their use as contrast agents for magnetic resonance imaging and oncological treatments. The information about the risk effects of ferrite NPs in human blood cells is, however, scarce. To assess their potential toxicity, in vitro studies were carried out with magnetite and zinc, nickel and nickel‑zinc ferrites NPs at different concentrations (50, 100 and 200 μg·ml^-1). The toxicity of the ferrite NPs was evaluated in humans by determining red blood hemolysis, by measuring the content of total proteins, and by assaying catalase and glutathione-S-transferase activities. Our results show that nickel‑zinc ferrite lead to hemolysis, and that magnetite, zinc and nickel‑zinc ferrites increase glutathione-S-transferase activity. No significant changes in human peripheral blood mononuclear cells viability were observed after the treatment with the four different ferrite NPs in vitro.

Oxidative stress mediated cytotoxicity and apoptosis response of bismuth oxide (Bi2O3) nanoparticles in human breast cancer (MCF-7) cells

Bismuth oxide nanoparticles (Bi₂O₃ NPs) have shown great potential for several applications including cosmetics and biomedicine. However, there is paucity of research on toxicity of Bi₂O₃ NPs. In this study, we first examined dose-dependent cytotoxicity and apoptosis response of Bi₂O₃ NPs in human breast cancer (MCF-7) cells. We further explored the potential mechanisms of cytotoxicity of Bi₂O₃ NPs through oxidative stress. Physicochemical study demonstrated that Bi₂O₃ NPs have crystalline structure and spherical shape with mean size of 97 nm. Toxicity studies have shown that Bi₂O₃ NPs reduce cell viability and induce membrane damage dose-dependently in the concentration range of 50-300 μg/ml. Bi₂O₃ NPs also disturbed cell cycle of MCF-7 cells. Oxidative stress response of Bi₂O₃ NPs was evident by generation of reactive oxygen species (ROS), higher lipid peroxidation, reduction of glutathione (GSH) and low superoxide dismutase (SOD) enzyme activity. Interestingly, supplementation of external antioxidant N-acetyl-cysteine almost negated the effect of Bi₂O₃ NPs induced oxidative stress and cell death. We also found that exposure of Bi₂O₃ NPs induced apoptotic response in MCF-7 cells suggested by impaired regulation of Bcl-2, Bax and caspase-3 genes. Altogether, we found that Bi₂O₃ NPs induced cytotoxicity in MCF-7 cells through modulating the redox homeostasis via Bax/Bcl-2 pathway. This study warranted further research to delineate the underlying mechanism of Bi₂O₃ NPs induced toxicity at in vivo level.

The toxicity of 2,6-dichlorobenzoquinone on the early life stage of zebrafish: A survey on the endpoints at developmental toxicity, oxidative stress, genotoxicity and cytotoxicity

2,6-dichlorobenzoquinone (2,6-DCBQ), an emerging disinfection by-production, frequently occurs in reclaimed water and drinking water. However, limited information was available regarding its toxicity. To evaluate its impact, zebrafish at early life stage were exposed to 0, 10, 30, 60, 90, or 120 μg L^-1 2,6-BDCQ for 72 h. Our results indicated that 2,6-BDCQ decreased zebrafish's survival rate to 65% and 44% at 90 and 120 μg L^-1 treatments and increased its aberration rate to 11% and 26% at 90 μg L^-1 and 120 μg L^-1 treatments. Besides, 2,6-BDCQ had adverse effect on its oxidative stress (elevated superoxide dismutase activity), lipid peroxidation (increased malondialdehyde levels), DNA damage (increased 8-hydroxydeoxyguanosine contents) and apoptosis (increased caspase-3 activity). Although lower concentrations (≤60 μg L^-1) of 2,6-BDCQ didn't exhibit significant effect on its survival development or lipid peroxidation of zebrafish, they induced obvious DNA damage and apoptosis occurrence. These results revealed 2,6-BDCQ caused genotoxicity and cytotoxicity to zebrafish. This study provides novel insight into 2,6-DCBQ-induced toxicity in zebrafish.

Cell Viability in Normal Fibroblasts and Liver Cancer Cells After Treatment with Iron (III), Nickel (II), and their Mixture

Introduction

Nickel and iron are very commonly occurring metals. Nickel is used in industry, but nowadays it is also used in medical biomaterials. Iron is an element necessary for cell metabolism and is used in diet supplements and biomaterials, whence it may be released along with nickel.

Material and Methods

BALB/3T3 and HepG2 cells were incubated with iron chloride or nickel chloride at concentrations ranging from 100 to 1,400 μM. The following mixtures were used: iron chloride 200 μM plus nickel chloride 1,000 μM, or iron chloride 1,000 μM plus nickel chloride 200 μM. The cell viability was determined with MTT, LHD, and NRU tests.

Results

A decrease in cell viability was observed after incubating the BALB/3T3 and HepG2 cells with iron chloride or nickel chloride. A synergistic effect was observed after iron chloride 1,000 μM plus nickel chloride 200 μM treatment in all assays. Moreover, the same effect was observed in the pair iron chloride 200 μM plus nickel chloride 1,000 μM in the LDH and NRU assays.

Conclusions

Iron (III) and nickel (II) decrease cell viability. Iron chloride at a concentration of 200 μM protects mitochondria from nickel chloride toxicity.

Corilagin induces apoptosis, autophagy and ROS generation in gastric cancer cells in vitro

Corilagin, a unique component of the tannin family, has been identified in several medicinal plants. In previous literature, corilagin exhibited a marked anticancer property in a variety of human cancer cells. However, the biological effects of corilagin on gastric cancer and the mechanisms involved remain to be fully elucidated. In the present study, it was reported that corilagin induced inhibition of cell growth in SGC7901 and BGC823 cells in a concentration-dependent manner. It was found that corilagin exhibited less toxicity towards normal GES-1 cells. Furthermore, the study showed that corilagin induced the apoptosis of gastric cancer cells mainly via activating caspase-8, -9, -3 and poly ADP-ribose polymerase proteins. Simultaneously, it was verified that corilagin triggered autophagy in gastric cancer cells and the inhibition of autophagy improved the activity of corilagin on cell growth suppression. In addition, corilagin significantly increased intracellular reactive oxygen species production, which is important in inhibiting the growth of gastric cancer cells. Finally, it was shown that necroptosis cannot be induced by corilagin-incubation in SGC7901 and BGC823 cell lines. Consequently, these findings indicate that corilagin may be developed as a potential therapeutic drug for gastric cancer.

Nickel-induced neurodegeneration in the hippocampus, striatum and cortex; an ultrastructural insight, and the role of caspase-3 and α-synuclein

Human overexposure to nickel (Ni) emanating from the increasing application of Ni compounds in modern technology is a major public health concern. Nickel has been shown to be teratogenic, immunotoxic, genotoxic and carcinogenic. The current knowledge on Ni neurotoxicity is still relatively limited. We have previously demonstrated that Ni treatment alters cognitive and locomotor behaviors, induces oxidative stress and neurodegeneration in brains of rats. In this study, we examine the ultrastructural changes to neurons in the hippocampus, striatum and cortex of the brain following Ni treatment, as well as attempt to delineate the roles for caspase-3 and α-synuclein in Ni-induced neurodegeneration. Rats were treated with either saline, 10 or 20 mg/kg of nickel chloride for 4 weeks via oral gavage. Electron microscopy analysis revealed ultrastructural alterations in neurons of the hippocampus, striatum and cortex following Ni treatment. Mitochondria structural integrity within neurons were markedly compromised. We also detected elevated caspase-3 activity in hippocampus and striatum, as well as overexpression of α-synuclein in the cortex following Ni treatment. Our study demonstrates that mitochondria are a key target in Ni-induced neurodegeneration. Additionally, we implicate apoptotic pathway via caspase-3 action as the executioner and perturbation of α-synuclein expression in Ni-induced neurodegeneration.

Nischarin attenuates apoptosis induced by oxidative stress in PC12 cells

Nischarin (NISCH) is a cytoplasmic protein known to serve an inhibitory role in breast cancer cell apoptosis, migration and invasion. Recently, NISCH has been reported to be involved in the regulation of spinal cord injury (SCI). However, the molecular mechanism is still unclear. Oxidative stress contributes to tissue injury and cell apoptosis during the development of various diseases, including SCI. The aim of the present study was to investigate the role of NISCH in the regulation of apoptosis induced by oxidative stress in PC12 cells. H₂O₂ was used to establish an oxidative stress model in PC12 cells. Apoptosis levels were examined using flow cytometry analysis, and the expression of NISCH, Bcl-2, Bcl-2-associated X (Bax) and caspase-3 were examined using western blot and immunofluorescence staining analyses. The results demonstrated that treatment with 100 µM H₂O₂ significantly increased the apoptotic rate and expression of NISCH in PC12 cells. At 48 h following incubation with 100 µM H₂O₂, NISCH downregulation partially inhibited apoptosis of PC12 cells. In addition, the expression of Bcl-2 was significantly reduced and the expression of Bax and caspase-3 were significantly increased by H₂O₂ treatment. These effects were also partially inhibited by the downregulation of NISCH. The authors of the present study therefore hypothesize that NISCH may function as a pro-apoptotic protein that participates in the regulation of oxidative stress, and NISCH downregulation may protect cells from oxidative stress-induced apoptosis.

Mesoporous multi-silica layer-coated Y2O3:Eu core-shell nanoparticles: Synthesis, luminescent properties and cytotoxicity evaluation

Mesoporous multi-layered silica-coated luminescent Y₂O₃:Eu nanoparticles (NPs) were prepared by a urea-based decomposition process, and their surfaces were gradually modified with nanoporous and mesoporous silica layers using modified sol-gel methods. The synthesized luminescent core-shell NPs were characterized thoroughly to investigate their structural, morphological, thermal, optical, photo luminescent properties and their surface chemistry. The morphology of the core NPs were nearly spherical in shape and were nano-sized grains. The observed luminescent efficiency of the mesoporous multi-layered silica-coated luminescent core NPs was gradually reduced because of bond formation between the Y₂O₃:Eu core and the amorphous silica shell via YOSiOH bridges on the surface of the NPs; the bonds suppressed the non-radiative transition pathways. Biocompatibility tests on Human breast cancer cells using the 3‑(4,5‑Dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide and lactate dehydrogenase assays indicated that the core-shell NPs were non-toxic even at high concentrations. The mesoporous SiO₂ layer played a key role in perfecting the solubility, biocompatibility, and non-toxicity of the NPs. The zeta potential, surface chemistry (Fourier transform infrared spectroscopy), and optical absorption spectral analyses revealed the high hydrophilicity of the as-prepared core-shell NPs because of the active surface-functionalized silanol (SiOH) groups, which could potentially offer many exciting opportunities in photonic-based biomedical applications.

The effect of Fe2NiO4 and Fe4NiO4Zn magnetic nanoparticles on anaerobic digestion activity

Two types of magnetic nanoparticles (MNPs), i.e. Ni ferrite nanoparticles (Fe₂NiO₄) and Ni Zn ferrite nanoparticles (Fe₄NiO₄Zn) containing the trace metals Ni and Fe, were added to the anaerobic digestion of synthetic municipal wastewater at concentrations between 1 and 100 mg Ni L^-1 in order to compare their effects on biogas (methane) production and sludge activity. Using the production of methane over time as a measure, the assays revealed that anaerobic digestion was stimulated by the addition of 100 mg Ni L^-1 in Fe₂NiO₄ NPs, while it was inhibited by the addition of 1-100 mg Ni L^-1 in Fe₄NiO₄Zn NPs. Especially at 100 mg Ni L^-1, Fe₄NiO₄Zn NPs resulted in a total inhibition of anaerobic digestion. The metabolic activity of the anaerobic sludge was tested using the resazurin reduction assay, and the assay clearly revealed the negative effect of Fe₄NiO₄Zn NPs and the positive effect of Fe₂NiO₄ NPs. Re-feeding fresh synthetic medium reactivated the NPs added to the anaerobic sludge, except for the experiment with 100 mg Ni L^-1 addition of Fe₄NiO₄Zn NPs. The findings in this present study indicate a possible new strategy for NPs design to enhance anaerobic digestion.

Different cytotoxic and apoptotic responses of MCF-7 and HT1080 cells to MnO2 nanoparticles are based on similar mode of action

Manganese (IV) oxide nanoparticles (MnO₂ NPs) are increasingly used in numerous applications. Multiple applications of MnO₂ NPs, however, increase the human exposure and thus potential risk related to their toxicity. There is little information regarding the toxicity mechanisms of MnO₂ NPs in human cells. In this study, we explored the toxic potential of MnO₂ NPs in human breast cancer epithelial (MCF-7) and human fibrosarcoma epithelial (HT1080) cells in order to examine whether epithelial cells of different origins showed similar responses. Results demonstrated that MnO₂ NPs induced cell viability reduction and membrane damage in both MCF-7 and HT1080 cells in a dose-dependent manner. MnO₂ NPs were also found to induce pro-oxidants generation and antioxidants depletion in both cells. We further observed that MnO₂ NPs induce apoptosis in both MCF-7 and HT1080 cells evident by altered regulation of apoptotic genes (p53, bax & bcl-2), cell cycle arrest and low mitochondrial membrane potential. Interestingly, we noticed that HT1080 cells were more susceptible to MnO₂ NPs exposure than those of MCF-7 cells. This could be due to higher level of MnO₂ NPs uptake into HT1080 cells as compared to MCF-7 cells. However, the mechanism of toxicity induced by MnO₂ NPs in both MCF-7 and HT1080 cells was highly similar. This study warrants further research to delineate the underlying mechanisms of MnO₂ NPs toxicity at in vivo level.

Nanoparticles induce apoptosis via mediating diverse cellular pathways

With a special size and structure, nanoparticles (NPs) have excellent application prospects in various fields and are widely used in the biomedicine, cosmetics and chemical industries nowadays. However, there have been some reports on the biosafety of this new type of material, pointing out its cytotoxicity in inducing apoptosis. With different physicochemical properties in size, shape, surface charge, and ligand, NPs exhibit different biocompatibilities when interacting with different cells. Therefore, a comprehensive and deep study into the proapoptotic mechanism of NPs is necessary. In the present review, we summarize the NP-triggered apoptotic signal pathways in detail and highlight some important functional molecules involved. We hope our findings and perspectives provide a new direction for the sound development of nanotechnology in the future.

Advances of magnetic nanoparticles in environmental application: environmental remediation and (bio)sensors as case studies

Nanotechnology is an emerging technique drawing increasing attentions in biomedical, electronic, environmental, and industrial application. Nanoparticles (NPs) possess unique optical, electrical, catalytic, and thermal properties, among which magnetic NPs (MNPs) are one of the most important groups with excellent superparamagnetism property, large surface area, and biocompatibility. In this review, methods for synthesizing and functionalizing MNPs are summarized and linked to their applications in environmental science as either adsorbents or catalysts for removing contaminants from environmental matrices, illustrating stronger reactivity, higher removal capacity, and fast kinetics. Additionally, we also comprehensively discuss the application of MNPs as (bio)sensors to selectively and sensitively detect the presence of environmental contaminants or pathogenic bacteria. This work summarizes the recent progresses of using MNPs as powerful tools in environmental science and engineering, raising their state-of-art application from environmental perspectives and benefiting researchers interested in NPs and environmental studies.

Selectivity and sensitivity of molybdenum oxide-polycaprolactone nanofiber composites on skin cancer: Preliminary in-vitro and in-vivo implications

Cancer nanomedicine has emerged as a revolution in the last decade opening up promising strides for the cancer treatment. The major challenge in these therapeutic approaches resides in the failure of clinical trials owing to the immunological cancer microenvironment. Therefore, the success of next generation nanomedicine depends on tunable physicochemical nanomaterial design and corresponding clinical trials by integrating targeted delivery with mitigated toxicity. The present study deals with the fabrication of nanofibrous scaffold impregnated with molybdenum nanoparticles for targeted skin cancer therapeutics. Molybdenum oxide, a transitional metal oxide is gaining rapid importance due to its vital role in cellular and molecular metabolism. Polycaprolactone nanofibers were chosen as a matrix to localize the nanoparticles topically facilitating selective apoptosis of the tumor cells over the normal cells with mitigated side effects. The scaffold was designed to tailor the physicochemical, mechanical and biological suitability for skin cancer (melanoma and non melanoma). The designed scaffold was found to reduce more than 50% cell viability of the cancer cells selectively through apoptosis as confirmed using AO/PI staining and the probable mechanism could be attributed to the induction of mitochondria dependent apoptosis as observed by JC1 dye staining. In-vivo trials in zebra fish were found to reduce cancer progression by more than 30% in 14 days. The fabricated molybdenum trioxide nano constructs not only serve as tunable targeted systems but also open venues capable of ferrying chemotherapeutic drugs sparing normal cells alleviating the trauma due to side effects.

Mn Inhibits GSH Synthesis via Downregulation of Neuronal EAAC1 and Astrocytic xCT to Cause Oxidative Damage in the Striatum of Mice

Excessive manganese (Mn) can accumulate in the striatum of the brain following overexposure. Oxidative stress is a well-recognized mechanism in Mn-induced neurotoxicity. It has been proven that glutathione (GSH) depletion is a key factor in oxidative damage during Mn exposure. However, no study has focused on the dysfunction of GSH synthesis-induced oxidative stress in the brain during Mn exposure. The objective of the present study was to explore the mechanism of Mn disruption of GSH synthesis via EAAC1 and xCT in vitro and in vivo. Primary neurons and astrocytes were cultured and treated with different doses of Mn to observe the state of cells and levels of GSH and reactive oxygen species (ROS) and measure mRNA and protein expression of EAAC1 and xCT. Mice were randomly divided into seven groups, which received saline, 12.5, 25, and 50 mg/kg MnCl₂, 500 mg/kg AAH (EAAC1 inhibitor) + 50 mg/kg MnCl₂, 75 mg/kg SSZ (xCT inhibitor) + 50 mg/kg MnCl₂, and 100 mg/kg NAC (GSH rescuer) + 50 mg/kg MnCl₂ once daily for two weeks. Then, levels of EAAC1, xCT, ROS, GSH, malondialdehyde (MDA), protein sulfhydryl, carbonyl, 8-hydroxy-2-deoxyguanosine (8-OHdG), and morphological and ultrastructural features in the striatum of mice were measured. Mn reduced protein levels, mRNA expression, and immunofluorescence intensity of EAAC1 and xCT. Mn also decreased the level of GSH, sulfhydryl, and increased ROS, MDA, 8-OHdG, and carbonyl in a dose-dependent manner. Injury-related pathological and ultrastructure changes in the striatum of mice were significantly present. In conclusion, excessive exposure to Mn disrupts GSH synthesis through inhibition of EAAC1 and xCT to trigger oxidative damage in the striatum.

Oxidative stress mediated cytotoxicity of tin (IV) oxide (SnO2) nanoparticles in human breast cancer (MCF-7) cells

Due to unique optical and electronic properties tin oxide nanoparticles (SnO₂ NPs) have shown potential for various applications including solar cell, catalyst, and biomedicine. However, there is limited information concerning the interaction of SnO₂ NPs with human cells. In this study, we explored the potential mechanisms of cytotoxicity of SnO₂ NPs in human breast cancer (MCF-7) cells. Results demonstrated that SnO₂ NPs induce cell viability reduction, lactate dehydrogenase leakage, rounded cell morphology, cell cycle arrest and low mitochondrial membrane potential in dose- and time-dependent manner. SnO₂ NPs were also found to provoke oxidative stress evident by generation of reactive oxygen species (ROS), hydrogen peroxide (H₂O₂) and lipid peroxidation, while depletion of glutathione (GSH) level and lower activity of several antioxidant enzymes. Remarkably, we observed that ROS generation, GSH depletion, and cytotoxicity induced by SnO₂ NPs were effectively abrogated by antioxidant N-acetylcycteine. Our data have shown that SnO₂ NPs induce toxicity in MCF-7 cells via oxidative stress. This study warrants further research to explore the genotoxicity of SnO₂ NPs in different types of cancer cells.

Parkinson disease-induced upregulation of apoptotic mediators could be attenuated in the skeletal muscle following chronic exercise training

BACKGROUND

We have shown elevated levels of p53 and active caspase-3 in gastrocnemius skeletal muscle with Parkinson's disease (PD). The main aim of this study is to examine the impact of endurance exercise training on the expression of p53 and active caspase-3 in the skeletal muscle of mouse with induced Parkinsonism.

METHODS

Sedentary control (SC), sedentary Parkinson diseased (SPD), and exercised Parkinson diseased (EPD) groups were formed; each consisting of 10 randomly selected normal albino mice. Chronic Parkinson disease was induced in the SPD and EPD animals using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and probenecid (MPTP/p). The expression of p53 and active caspase-3 was investigated, using immunohistochemistry, in the gastrocnemius muscle in each animal group.

RESULTS

Both p53 and active caspase-3 expression was significantly (p value < 0.05) reduced in the PD gastrocnemius skeletal muscle following endurance exercise training.

CONCLUSION

Our present data suggest that chronic exercise training reduced Parkinson disease-induced upregulation of p53 and active caspase-3 in gastrocnemius skeletal muscle. Thus, our study suggests that inhibiting p53 and/or active caspase-3 may be considered as a therapeutic approach to ameliorate PD skeletal muscle abnormalities.

Probing Cellular Processes Using Engineered Nanoparticles

Nanoparticles, the building blocks of nanotechnology, have been widely utilized in various biomedical applications, such as detection, diagnosis, imaging, and therapy. However, another emerging, albeit under-represented, area is the employment of nanoparticles as tools to understand cellular processes (e.g., oxidative stress-induced signaling cascades). Such investigations have enormous potential to characterize a disease from a different perspective and unravel some new features that otherwise would have remained a mystery. In this review, we summarize the intrinsic biological properties of unmodified as well surface modified nanoparticles and discuss how such properties could be utilized to interrogate biological processes and provide a perspective for future evolution of this field.

Enhanced steroidogenic and altered antioxidant response by ZnO nanoparticles in mouse testis Leydig cells

Zinc oxide nanoparticles (ZnO NPs) are important nanomaterials with myriad applications and in widespread use. The main aim of this study was to evaluate the direct effect of ZnO NPs on steroidogenesis by considering mouse testicular Leydig cells (TM3) as an in vitro model system. The uptake, intracellular behaviour, cytotoxicity and morphological changes induced by ZnO NPs (0-200 µg/ml) in a time-dependent manner in the TM3 were assessed. A significant ( p < 0.05) decrease in TM3 viability was observed at 2 µg/ml ZnO NP after a 1-h incubation time period. Increased antioxidant enzyme activity, namely, superoxide dismutase (SOD) and catalase, was regularly observed. Not surprisingly, apoptosis also increased significantly after a 4-h exposure period. Transmission electron micrographs illustrated that ZnO NPs were taken up by Leydig cells and resulted in the formation of autophagosomes, autolysosomes and autophagic vacuoles. Concomitant real-time data indicated that ZnO NPs significantly increased the expression of steroidogenesis-related genes (steroidogenic acute regulatory protein and cytochrome P450 side-chain cleavage enzyme) and significantly ( p < 0.05) decreased antioxidant enzyme gene (SOD) expression after a 4-h incubation period. Moreover, ZnO NPs exposure significantly increased testosterone production at 2 µg/ml concentration after a 12-h incubation period. Our findings confirm the adverse effects of ZnO NPs by being cytotoxic, enhancing apoptosis, causing steroidogenic effect in Leydig cells and increasing autophagic vacuole formation possibly via alteration of antioxidant enzyme activity in TM3 cells.

Metabolic fate and subchronic biological effects of core-shell structured Fe3O4@SiO2-NH2 nanoparticles

Core-shell structured Fe₃O₄@SiO₂-NH₂ nanoparticles (Fe@Si-NPs) demonstrated outstanding potentials in drug targeting and delivery and medical imaging. However, they have limited clinical applications due to unknown chronic bio-effects and potential bio-related risks. In this study, the subchronic biological effects and metabolic fate of 20 nm Fe@Si-NPs in Sprague-Dawley rats in 12 weeks were investigated by the biochemical assay and NMR-based metabonomic analysis using an intravenous model. Biofluids (plasma and urine) analysis provided the transportation, absorption, and excretion information of Fe@Si-NPs. Urine metabonome displayed a metabolic recovery while self-regulation of plasma metabonome leaded to the parallel metabolic trends between dosed and control groups in 12 weeks. And biological tissues (spleen, liver, kidney, and lung) analysis indicated liver and spleen are the targeted-organs of Fe@Si-NPs. The obvious metabolic variations responding to the biodistribution were induced by Fe@Si-NPs although no visible toxic effects were observed in these tissues. Besides the common energy metabolism response to the xenobiotics, Fe@Si-NPs also disturbed the metabolic pathways in glycerophospholipid and sphingolipid metabolism, metabolisms of purine, pyrimidine, and nicotinate. Our results provide preliminary validation for the potential use of Fe@Si-NPs in clinical medicine and give identifiable ground for the dose selection and bio-nanoagent optimization.