MicroRNA-Mediated Antiproliferative Effects of M1 Macrophage-Derived Extracellular Vesicles on Melanoma Cells.

INTRODUCTION: Research in tumor treatment has shown promising results using extracellular vesicles (EVs) derived from immune cells. EVs derived from M1 macrophages (proinflammatory), known as M1-EVs, have properties that suppress tumor growth, making them a promising treatment tool for immune susceptible tumors such as melanoma. Here, small unaltered M1-EVs (M1-sEVs) were employed in a 3D mouse melanoma model (melanospheres) to evaluate such activity. METHODS: Macrophages were polarized and EVs were isolated by ultracentrifugation. The EVs obtained were characterized based on size, with measurements performed by dynamic light scattering and electron microscopy, and the expression profiles of microRNAs were analyzed by microarray and PCR. Melanospheres were used to evaluate the cytotoxicity of M1-sEVs. Pondering a possible future transposition from the animal model to the human, human melanoma cells were transfected with a specific miRNA, and the impact on cell proliferation was evaluated. RESULTS: The isolated EVs showed a size distribution between 50-400 nm in diameter, but preeminently in a range of 70-90 nm. M1-sEVs demonstrated a remarkable ability to reduce cell proliferation and viability in the melanospheres, leading to a decrease in their volume. M1-sEVs contained unique miRNAs, including miR-29a-3p, which exhibited significant antitumor activities according to bioinformatics analysis. Validation of the antitumor effects of miR-29a-3p was obtained by a functional evaluation, i.e., by inducing miRNA overexpression in human melanoma cells (SK-MEL-28). CONCLUSION: Although further research would be advisable, the study provides evidence supporting the potential of M1-sEVs and their miRNA load as a possible targeted immune therapy for melanoma.

MicroRNAs: Potential biomarkers for reproduction, diagnosis, prognosis, and therapeutic in domestic animals.

MicroRNA (miRNAs) are small non-coding RNA molecules involved in a wide range of biological processes through the post-transcriptional regulation of gene expression. Most studies evaluated microRNA expression in human, and despite fewer studies in veterinary medicine, this topic is one of the most exciting areas of modern veterinary medicine. miRNAs showed to be part of the pathogenesis of diseases and reproduction physiology in animals, making them biomarkers candidates. This review provides an overview of the current knowledge regarding miRNAs' role in reproduction and animal diseases, diagnostic and therapy.

Pro-angiogenic effect of PC-3 exosomes in endothelial cells in vitro.

The progression to a castration-resistant prostate cancer can occur after treatment with androgen deprivation therapy, resulting in poor prognosis and ineffective therapy response. Hormone dependence transition has been associated with increased tumor vascularization. Considering that exosomes are important components in communication between tumor cells and the microenvironment, we examined the angiogenic potential of exosomes released from Pca cell lines with distinctive profiles of androgen response through exosomes isolation, microscopy and uptake, functional assays follow up by microarray, RT-qPCR and bioinformatics analysis. HUVEC cells treated with PC-3 exosomes (androgen independent) showed increased invasion and tube formation ability. In order to identify microRNAs (miRNAs) related to the angiogenic response, the characterization of exosomal miRNA profile was performed. As result we suggest that the miR-27a-3p could be involved in the pro-angiogenic effect of PC-3 exosomes.

miR-425-5p as an exosomal biomarker for metastatic prostate cancer.

Prostate cancer-related deaths are mostly caused by metastasis, which indicates the importance of identifying clinical prognostic biomarkers. In this study, we evaluated the expression profile of exosomal microRNAs (miRNAs) derived from metastatic prostate cancer (mPCa) cell lines (LNCaP and PC-3). miRNA signatures in exosomes and cells were evaluated by miRNA microarray analysis. Fourteen miRNAs were identified as candidates for specific noninvasive biomarkers. The expression of five miRNAs was validated using RT-qPCR, which confirmed that miR-205-5p, miR-148a-3p, miR-125b-5p, miR-183-5p, and miR-425-5p were differentially expressed in mPCa exosomes. Bioinformatic analyses showed that miR-425-5p was associated with residual tumor, pathologic T and N stages, and TP53 status in PCa samples. Gene ontology analysis of negatively correlated and predicted targeted genes showed enrichment of genes related to bone development pathways. The LinkedOmics database indicated that the potential target HSPB8 has a significant negative correlation with miR-425-5p. In conclusion, this study identified a panel of exosomal miRNAs with potential value as prognostic biomarkers for prostate cancer.

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.

Three-dimensional multicellular cell culture for anti-melanoma drug screening: focus on tumor microenvironment.

ABSTRACT: The development of new treatments for malignant melanoma, which has the worst prognosis among skin neoplasms, remains a challenge. The tumor microenvironment aids tumor cells to grow and resist to chemotherapeutic treatment. One way to mimic and study the tumor microenvironment is by using three-dimensional (3D) co-culture models (spheroids). In this study, a melanoma heterospheroid model composed of cancer cells, fibroblasts, and macrophages was produced by liquid-overlay technique using the agarose gel. The size, growth, viability, morphology, cancer stem-like cells population and inflammatory profile of tumor heterospheroids and monospheroids were analyzed to evaluate the influence of stromal cells on these parameters. Furthermore, dacarbazine cytotoxicity was evaluated using spheroids and two-dimensional (2D) melanoma model. After finishing the experiments, it was observed the M2 macrophages induced an anti-inflammatory microenvironment in heterospheroids; fibroblasts cells support the formation of the extracellular matrix, and a higher percentage of melanoma CD271 was observed in this model. Additionally, melanoma spheroids responded differently to the dacarbazine than the 2D melanoma culture as a result of their cellular heterogeneity and 3D structure. The 3D model was shown to be a fast and reliable tool for drug screening, which can mimic the in vivo tumor microenvironment regarding interactions and complexity.

MicroRNA profiles in serum samples from Acute-On-Chronic Liver Failure patients and miR-25-3p as a potential biomarker for survival prediction.

Acute-on-chronic liver failure (ACLF) is a condition characterized by acute decompensation of cirrhosis, associated with organ failure(s), and high short-term mortality. The microRNAs or miRNAs are small non-coding RNA molecules, stable in circulating samples such as biological fluids, and the difference in expression levels may indicate the presence, absence and/or stage of the disease. We analyzed here the miRNA profiling to identify potential diagnostic or prognostic biomarkers for ACLF. The major miRNAs discovered were validated in a cohort of patients with acute decompensation of cirrhosis grouped in no ACLF or ACLF according to EASL-CLIF definition. Relationship between serum miRNAs and variables associated with liver-damage and survival outcomes were verified to identify possible prognostic markers. Our results showed twenty altered miRNAs between no ACLF and ACLF patients, and twenty-seven in patients who died in 30 days compared with who survived. In validation phase, miR-223-3p and miR-25-3p were significantly altered in ACLF patients and in those who died in 30 days. miR-223-3p and miR-25-3p expression were associated with the lowest survival in 30 days. The decrease in miR-223-3p and miR-25-3p expression was associated with the presence of ACLF and poor prognosis. Of these, miR-25-3p was independently related to ACLF and 30-day mortality.

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.

Magnetically responsive hybrid nanoparticles for in vitro siRNA delivery to breast cancer cells.

Short interfering RNA (siRNA) showed to be a viable alternative to a better prognosis in cancer therapy. Nevertheless, the successful application of this strategy still depends on the development of nanocarriers for the safe delivery of siRNA into the diseased tissue, which mostly occurs by passive accumulation. When an external magnetic field is applied, magnetic nanoparticles biodistribution is partially modulated to favor accumulation in a target tissue. In this work we designed a novel magnetic responsive siRNA nanocarrier. The new delivery system is composed of superparamagnetic iron oxide nanoparticles (SPIONs) coated with calcium phosphate (CaP) and PEG-polyanion block copolymers, which are known to be biocompatible. The nanoparticles presented rounded shape with small size and narrow distribution suitable for biomedical applications. TEM images showed dark spheres in the core surrounded by a lower electron density material in the corona. The X-ray photoelectron spectra (XPS) confirmed CaP-polymer coating of the magnetic core. In addition, the coating procedure did not affect the superparamagnetic property as showed using a vibrating sample magnetometer (VSM). With a high loading efficiency (80%), the nanoparticles enhanced vascular endothelium growth factor (VEGF) silencing in breast cancer cells in vitro, at gene and protein levels (~60% and 40%, respectively), without associated toxicity. Iron and siRNA quantification showed that the novel nanoparticles move towards a magnetic source carrying siRNA molecules. Therefore, these novel nanoparticles are a promising tool for cancer therapy based on RNAi effect, added by a magnetic capability to further modulate siRNA accumulation in the target tissue.

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.

Tacrine derivatives stimulate human glioma SF295 cell death and alter important proteins related to disease development: An old drug for new targets.

Glioblastoma is the most common and aggressive glioma, characterized by brain invasion capability. Being very resistant to the current therapies, since even under treatment, surgery, and chemotherapy with temozolomide (TMZ), patients achieve a median survival of one year. In the search for more effective therapies, new molecules have been designed. For nervous system cancers, molecules able to cross the blood-brain barrier are handled with priority. Accordingly, tacrine was chosen for this study and the inclusion of spiro-heterocyclic rings was done in its structure resulting in new compounds. Cytotoxic activity of tacrine derivatives was assayed using glioblastoma cell line (SF295) as well as analyzing cell death mechanism. Increased caspases activities were observed, confirming apoptosis as cell death type. Some derivatives also increased reactive oxygen species formation and decreased the mitochondrial membrane potential. Moreover, compounds acted on several glioblastoma-related proteins including p53, HLA-DR, beta-catenin, Iba-1, MAP2c, Olig-2, and IDH1. Therefore, tacrine derivatives presented promising results for the development of new glioblastoma therapy, particularly to treat those patients resistant to TMZ.

Allylic isothiouronium salts: The discovery of a novel class of thiourea analogues with antitumor activity.

A series of 28 aryl- and alkyl-substituted isothiouronium salts were readily synthesized in high yields through the reaction of allylic bromides with thiourea, N-monosubstituted thioureas or thiosemicarbazide. The S-allylic isothiouronium salts substituted with aliphatic groups were found to be the most effective against leukemia cells. These compounds combine high antitumor activity and low toxicity toward non-tumoral cells, with selectivity index higher than 20 in some cases. Furthermore, the selected isothiouronium salts induced G2/M cell cycle arrest and cell death, possibly by apoptosis. Therefore, these compounds can be considered as a promising class of antitumor agents due to the potent cytostatic activity associated with high selectivity.

Knockdown of antiapoptotic genes in breast cancer cells by siRNA loaded into hybrid nanoparticles.

Tumorigenesis is related to an imbalance in controlling mechanisms of apoptosis. Expression of the genes BCL-2 and BCL-xL results in the promotion of cell survival by inhibiting apoptosis. Thus, a novel approach to suppress antiapoptotic genes is the use of small interfering RNA (siRNA) in cancer cells. However, there are some limitations for the application of siRNA such as the need for vectors to pass the cell membrane and deliver the nucleic acid. In this study CaP-siRNA-PEG-polyanion hybrid nanoparticles were developed to promote siRNA delivery to cultured human breast cancer cells (MCF-7) in order to evaluate whether the silencing of antiapoptotic genes BCL-2 and BCL-xL by siRNA would increase cancer cell death. After 48 h of incubation the expression of BCL-2 and BCL-xL genes decreased to 49% and 23%, respectively. The siRNA sequence used induced cancer cell death at a concentration of 200 nM siRNA after 72 h of incubation. As the targeted proteins are related to the resistance to chemotherapeutic drugs, the nanocarriers systems were also tested in the presence of doxorubicin (DOX). The results showed a significant reduction in the CC50 of the DOX, after silencing the antiapoptotic genes. In addition, an increase in apoptotic cell counts for both incubations conditions was observed as well. In conclusion, silencing antiapoptotic genes such as BCL-2 and BCL-xL through the use of siRNA carried by hybrid nanoparticles showed to be effective in vitro, and presents a promising strategy for pre-clinical analysis, especially when combined with DOX against breast cancer.

Influence of surfactant and lipid type on the physicochemical properties and biocompatibility of solid lipid nanoparticles.

Nine types of solid lipid nanoparticle (SLN) formulations were produced using tripalmitin (TPM), glyceryl monostearate (GM) or stearic acid (SA), stabilized with lecithin S75 and polysorbate 80. Formulations were prepared presenting PI values within 0.25 to 0.30, and the physicochemical properties, stability upon storage and biocompatibility were evaluated. The average particle size ranged from 116 to 306 nm, with a negative surface charge around -11 mV. SLN presented good stability up to 60 days. The SLN manufactured using SA could not be measured by DLS due to the reflective feature of this formulation. However, TEM images revealed that SA nanoparticles presented square/rod shapes with an approximate size of 100 nm. Regarding biocompatibility aspects, SA nanoparticles showed toxicity in fibroblasts, causing cell death, and produced high hemolytic rates, indicating toxicity to red blood cells. This finding might be related to lipid type, as well as, the shape of the nanoparticles. No morphological alterations and hemolytic effects were observed in cells incubated with SLN containing TPM and GM. The SLN containing TPM and GM showed long-term stability, suggesting good shelf-life. The results indicate high toxicity of SLN prepared with SA, and strongly suggest that the components of the formulation should be analyzed in combination rather than separately to avoid misinterpretation of the results.

Involvement of extrinsic and intrinsic apoptotic pathways together with endoplasmic reticulum stress in cell death induced by naphthylchalcones in a leukemic cell line: advantages of multi-target action.

Chalcones, naturally occurring open-chain flavonoids abundant in plants, have demonstrated anticancer activity in multiple tumor cells. In a previous work, the potential anticancer activity of three naphthylchalcones named R7, R13 and R15 was shown. In this study, the mechanism of actions of these chalcones was originally shown. The chalcones presented concentration and time-dependent cytotoxicity. To determine the type of cell death induced by chalcones, we assessed a series of assays including measurements of the caspase-8, -9 and -12 activities, expression of important apoptosis-related genes and proteins, changes in the cell calcium concentration and cytochrome c release. The activities of caspase-8, -9 and -12 increased after the treatment of L1210 cells with the three compounds. Chalcones R7 and R13 induced an increase of pro-apoptotic proteins Bax, Bid and Bak (only chalcone R13), as well as a decrease in anti-apoptotic Bcl-2 expression. These chalcones also induced an increase in Fas and a decrease in p21 and p53 expression. Chalcone R15 seems to act by a different mechanism to promote cell death, as it did not change the mitochondrion-related proteins, nor did it induce the cytochrome c release. All compounds induced an increase in cell calcium concentration and an increase in CHOP expression, which together with an increase in caspase-12 activity, suggest that chalcones could induce an endoplasmic reticulum (ER) stress. Taken together, these results suggest that chalcones induce apoptosis by different pathways, being an interesting strategy to suggest for cancer therapy.

Solid lipid nanoparticles induced hematological changes and inflammatory response in mice.

Solid lipid nanoparticles (SLNs) are an alternative drug delivery system compared to emulsions, liposomes and polymeric nanoparticles. Due to their unique sizes and properties, SLNs offer possibility to develop new therapeutic approaches. The ability to incorporate drugs into nanocarriers offers a new prototype in drug delivery that could be used for drug targeting. However, toxicity of these new formulations has not been investigated thus far. In this study, we carried out an in vivo toxicity study. For that mice were divided into three groups and treated intraperitoneally with triestearin-based SLNs (TN), natural wax-based SLNs (VN) or vehicle for 10 days. After that, necropsies, histopathological and hematological analysis, as well as hepatic and renal functions were performed. Our results indicated that both TN and VN were absorbed post-exposure and induced an inflammatory response in adipose tissue. However, histopathological analysis demonstrated the absence of toxicity in both treated groups. In addition, the body weights were similar among the groups and low toxicity was also indicated by the unchanged serum biochemical parameters. This study provides a preliminary data for toxicological studies of two different SLNs in long-term in vivo exposure. However, further studies should be conducted in order to investigate the inflammatory response in order to establish the safety of these SLNs.

In vitro biocompatibility of solid lipid nanoparticles.

This study was undertaken to address the current deficient knowledge of cellular response to solid lipid nanoparticles (SLNs) exposure. We investigated the cytotoxicity of several SLNs formulations in two fibroblast cell lineages, Vero and MDCK. Several methods were used to explore the mechanisms involved in this cytotoxic process, including cell viability assays, flow cytometry and ROS generation assessment. Among nanoparticles tested, two of them (F4 and F5) demonstrated more cytotoxic effects in both cell lineages. The cell viability assays suggested that F4 and F5 interfere in cell mitochondrial metabolism and in lysosomal activity. In addition, F5 decreased the percentage of MDCK cells in G0/G1 and G2/M phases, with a marked increase in the Sub/G1 population, suggesting DNA fragmentation. Regarding F4, although IC(50) was higher (~700 µg/mL), this formulation affected mitochondrial membrane potential for Vero cells. However, the IC(50) of F5 was around 250 µg/mL, suggesting the effect of SDS (sodium dodecyl sulfate) present in the formulation. In summary, the nanoparticles tested here appears to be biocompatible, with the exception of F5. Further studies are required to elucidate the in vivo effects of these nanoscale structures, in order to evaluate or predict the connotation of their increased and widespread use.