Short interfering RNA delivered by a hybrid nanoparticle targeting VEGF: Biodistribution and anti-tumor effect.

BACKGROUND: The use of RNA interference (iRNA) therapy has proved to be an interesting target therapy for the cancer treatment; however, siRNAs are unstable and quickly eliminated from the bloodstream. To face these barriers, the use of biocompatible and efficient nanocarriers emerges as an alternative to improve the success application of iRNA to the cancer, including breast cancer. RESULTS: A hybrid nanocarrier composed of calcium phosphate as the inorganic phase and a block copolymer containing polyanions as organic phase, named HNPs, was developed to deliver VEGF siRNA into metastatic breast cancer in mice. The particles presented a rounded shape by TEM images with average size measured by DLS suitable and biocompatible for biomedical applications. The XPS and EDS spectra confirmed the hybrid composition of the nanoparticles. Moreover, after intravenous administration, the particles accumulated mainly in the tumor site and kidneys, which demonstrates the tumor targeting accumulation through the Enhanced Permeability and Retention Effect (EPR). A significant decrease in size of the tumors treated with the nanoparticles containing siVEGF (HNPs-siVEGF) was observed and the reduction was related to enhanced tumor accumulation of siRNA as well as in vivo VEGF silencing at gene and protein levels. CONCLUSION: The hybrid system prepared was successful in promoting the RNAi effect in vivo with very low toxicity. GENERAL SIGNIFICANCE: This study shows the valuable development of a hybrid nanoparticle carrying VEGF siRNA, as well as their tumor targeting, accumulation and reduction in mice triple-negative breast cancer.

Antitumor activity of methyl (Z)-2-(isothioureidomethyl)-2-pentenoate hydrobromide against leukemia cell lines via mitotic arrest and apoptotic pathways.

In a previous study, we described a series of 28 aryl- and alkyl-substituted isothiouronium salts with antitumor activity and selectivity toward a leukemia cell line. Among the synthesized compounds, methyl (Z)-2-(isothioureidomethyl)-2-pentenoate hydrobromide (IS-MF08) showed conspicuous activity. In the present study, we investigated the mechanism of action of IS-MF08. Our results showed that its mechanism most likely is related with the membrane receptor Fas and subsequent activation of the extrinsic cell death pathway, triggered by a decrease in the levels of the anti-apoptotic protein Bcl-2 and caspase-8 and -3 cascade activation, causing DNA damage and mitotic arrest. IS-MF08 also caused an increase in intracellular ROS, endoplasmic reticulum (ER) stress, and mitochondrial membrane permeabilization, resulting in organelle degradation as an attempt to reestablish cell homeostasis. Furthermore, cells exposed to IS-MF08 combined to an autophagy inhibitor were less susceptible to compound's cytotoxicity, suggesting that autophagy makes part of its mechanism of action. These data support the hypothesis that IS-MF08 acts by the apoptosis extrinsic pathway and possibly by autophagy as mechanisms of cell death.

Genetic, reproductive and oxidative damage in mice triggered by co-exposure of nanoparticles: From a hypothetical scenario to a real concern.

Humans are potentially exposed to multiple nanoparticles kinds through nanotechnology-based consumer products. There is insufficient data on the in vivo toxicity of nanotechnology products, as well as no data on the possible toxicity, including genotoxicity and reproductive toxicity of co-exposure to different kind of nanoparticles. In this work, solid lipid nanoparticles (SLNs) and superparamagnetic iron oxide nanoparticles (SPIONs) were selected for evaluation of a hypothetical condition of in vivo co-exposure. Genotoxicity of SPIONs and SLNs was performed separately and in 1:1 mixture in mice. Bone marrow micronucleus assay, sperm morphology test, and sperm count were carried out. Also, the serum ALT and AST activities; and hematological parameters of the treated mice were analyzed. The results showed a significant increase (p < 0.05) in micronucleated polychromatic erythrocytes (MNPCE) and nuclear abnormalities (NA) in SPIONs, SLNs and their mixture treated mice. The mixture induced the highest frequency of MNPCE and NA. A similar result was observed in the sperm morphology test, with the mixture inducing the highest sperm abnormalities, followed by SLNs and the least by SPIONs. Significant alteration to RDW, MCHC, MCV, GRAN, and platelets, as well as increased activities of serum AST were observed in the mice treated with a mixture of the two kinds of nanoparticles. Calculation of interaction factor showed a possible synergistic effect between SPIONs and SLNs in MNPCE, NA and sperm morphology studied. Even as a hypothetical scenario of co-exposure to SLNs and SPIONs, this study showed, for the first time, that co-exposure to SPIONs and SLNs is more genotoxic to somatic and germ cells than their individual exposure.