Assessing the antiproliferative effect of biogenic silver chloride nanoparticles on glioblastoma cell lines by quantitative image-based analysis.

Glioblastoma is the most life-threatening tumour of the central nervous system. Temozolomide (TMZ) is the first-choice oral drug for the treatment of glioblastoma, although it shows low efficacy. Silver nanoparticles (AgNPs) have been shown to exhibit biocidal activity in a variety of microorganisms, including some pathogenic microorganisms. Herein, the antiproliferative effect of AgCl-NPs on glioblastoma cell lines (GBM02 and GBM11) and on astrocytes was evaluated through automated quantitative image-based analysis (HCA) of the cells. The cells were treated with 0.1-5.0 µg/ml AgCl-NPs or with 9.7-48.5 µg/ml TMZ. Cells that received combined treatment were also analysed. At a maximum tested concentration of AgCl-NPs, GBM02 and GBM11, the growth decreased by 93% and 40%, respectively, following 72 h of treatment. TMZ treatment decreased the proliferation of GBM02 and GBM11 cells by 58% and 34%, respectively. Combinations of AgCl-NPs and TMZ showed intermediate antiproliferative effects; the lowest concentrations caused an inhibition similar to that obtained with TMZ, and the highest concentrations caused inhibition similar to that obtained with AgCl-NPs alone. No significant changes in astrocyte proliferation were observed. The authors' findings showed that HCA is a fast and reliable approach that can be used to evaluate the antiproliferative effect of the nanoparticles at the single-cell level and that AgCl-NPs are promising agents for glioblastoma treatment.

Cellular toxicology and mechanism of the response to silver-based nanoparticle exposure in Ewing's sarcoma cells.

Ewing's sarcoma is the most aggressive connective tissue tumor, mainly affecting children and adolescents; the 5 year survival rate is only 50%. Current treatments have poor effectiveness, and more efficient treatments are being sought. Silver-based nanoparticles, such as silver chloride nanoparticles (AgCl-NPs) and silver/silver chloride (Ag/AgCl-NPs) nanoparticles, can be biologically produced and can release Ag+ ions into solution; however, their antitumor activity has been minimally investigated. The aim of this study was to evaluate the antitumor potential of AgCl-NPs and Ag/AgCl-NPs against Ewing's sarcoma cells. A673 cells (Ewing's sarcoma) were treated for 72 h with 0-12.5 µg ml-1 of Ag/AgCl-NPs or 0-40 µg ml-1 of AgCl-NPs. Human cells from the RPE-1 cell line (pigmented retinal epithelium) were used as a model of nontumor cells. The RPE-1 cells were less affected by the administration of AgCl-NPs or Ag/AgCl-NPs, with small reductions in the number of cells and viability and a small increase in apoptosis rates, while lysosomal damage, changes in reactive oxygen species (ROS) production, loss of mitochondrial membrane potential and alterations in microfilaments or cell areas were not observed. A673 tumor cells had significantly reduced number and viability levels when treated with AgCl-NPs, with reductions of 65.05% and 99.17%, respectively, whereas with Ag/AgCl-NP treatment, reductions of 65.53% and 92.51% were observed, respectively. When treated with silver-based nanoparticles, A673 cells also showed a significant increase in ROS production and loss of mitochondrial membrane potential, which culminated in an increase in the percentage of apoptosis among the population. Lysosomal damage was also observed when A673 cells were treated with the highest concentration of AgCl-NPs. In conclusion, the results showed that both AgCl-NPs and Ag/AgCl-NPs had some antitumor activity with minimal effects against healthy cells, which demonstrated the possibility of their use in cancer therapy.

Silver/silver chloride nanoparticles inhibit the proliferation of human glioblastoma cells.

Glioblastomas (GBM) are aggressive brain tumors with very poor prognosis. While silver nanoparticles represent a potential new strategy for anticancer therapy, the silver/silver chloride nanoparticles (Ag/AgCl-NPs) have microbicidal activity, but had not been tested against tumor cells. Here, we analyzed the effect of biogenically produced Ag/AgCl-NPs (from yeast cultures) on the proliferation of GBM02 glioblastoma cells (and of human astrocytes) by automated, image-based high-content analysis (HCA). We compared the effect of 0.1-5.0 µg mL-1 Ag/AgCl-NPs with that of 9.7-48.5 µg mL-1 temozolomide (TMZ, chemotherapy drug currently used to treat glioblastomas), alone or in combination. At higher concentrations, Ag/AgCl-NPs inhibited GBM02 proliferation more effectively than TMZ (up to 82 and 62% inhibition, respectively), while the opposite occurred at lower concentrations (up to 23 and 53% inhibition, for Ag/AgCl-NPs and TMZ, respectively). The combined treatment (Ag/AgCl-NPs + TMZ) inhibited GBM02 proliferation by 54-83%. Ag/AgCl-NPs had a reduced effect on astrocyte proliferation compared with TMZ, and Ag/AgCl-NPs + TMZ inhibited astrocyte proliferation by 5-42%. The growth rate and population doubling time analyses confirmed that treatment with Ag/AgCl-NPs was more effective against GBM02 cells than TMZ (~ 67-fold), and less aggressive to astrocytes, while Ag/AgCl-NP + TMZ treatment was no more effective against GBM02 cells than Ag/AgCl-NPs monotherapy. Taken together, our data indicate that 2.5 µg mL-1 Ag/AgCl-NPs represents the safest dose tested here, which affects GBM02 proliferation, with limited effect on astrocytes. Our findings show that HCA is a useful approach to evaluate the antiproliferative effect of nanoparticles against tumor cells.

On the synergy between silver nanoparticles and doxycycline towards the inhibition of Staphylococcus aureus growth.

In a previous paper (RSC Adv., 2015, 5, 66886-66893), we showed that the combination of silver nanoparticles (NanoAg) with doxycycline (DO) culminated in an increased bactericidal activity towards E. coli. Herein we further investigated the metabolic changes that occurred on Staphylococcus aureus upon exposure to NanoAg with the help of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) coupled with multivariate data analysis. It has been discovered that the combination of DO with NanoAg produced metabolic changes in S. aureus that were not simply the overlap of the treatments with DO and NanoAg separately. Our results suggest that DO and NanoAg act synergistically to impede protein synthesis by the bacteria.

Anti-inflammatory, analgesic and anti-tumor properties of gold nanoparticles.

BACKGROUND: Gold nanoparticles (GNPs) are regarded as potential platforms for drug delivery. However, their interaction with live organisms must be understood prior to their utilization as drug carriers. The present study reports the anti-inflammatory, analgesic and anti-tumor effects of GNPs. The biodistribution of GNPs and their effect on various tissues have also been studied. METHODS: GNPs were synthesized through an environmentally friendly route and characterized with TEM and UV-vis. After HT-29 cells had been exposed to GNPs, apoptosis was assessed with Annexin V and propidium iodide staining and caspase-3 activity determined with a confocal laser scanning microscope. GNPs were administrated to male and female Swiss mice for posterior assessment of their anti-inflammatory and analgesic properties. The biodistribution of GNPs and their impact on tissues were studied with UV-vis and histopathological analysis, respectively. RESULTS: Cell apoptosis was observed in a dose-dependent manner for GNPs concentrations ranging from 40µg/mL to 80µg/mL (p<0.05). The best anti-inflammatory activity was observed at the dose of 1500µg/kg, which caused a reduction of 49.3% in leukocyte migration. GNPs showed peripheral analgesia at the dose of 1500µg/kg and have been found in liver, spleen, kidney and lungs. Histopathological examination revealed extravasation of red blood cells in lungs. CONCLUSION: The study draws attention to gold nanoparticles as a resource for technological innovation in the anti-inflammatory, analgesic and anti-tumor fields. GNPs have biological effects that deserve investigation to assess their full interaction with organic systems.