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.

The Bone Microenvironment Soil in Prostate Cancer Metastasis: An miRNA Approach.

Bone metastatic prostate cancer (PCa) is associated with a high risk of mortality. Changes in the expression pattern of miRNAs seem to be related to early aspects of prostate cancer, as well as its establishment and proliferation, including the necessary steps for metastasis. Here we compiled, for the first time, the important roles of miRNAs in the development, diagnosis, and treatment of bone metastasis, focusing on recent in vivo and in vitro studies. PCa exosomes are proven to promote metastasis-related events, such as osteoblast and osteoclast differentiation and proliferation. Aberrant miRNA expression in PCa may induce abnormal bone remodeling and support tumor development. Furthermore, miRNAs are capable of binding to multiple mRNA targets, a dynamic property that can be harnessed for the development of treatment tools, such as antagomiRs and miRNA mimics, which have emerged as promising candidates in PCa treatment. Finally, miRNAs may serve as noninvasive biomarkers, as they can be detected in tissue and bodily fluids, are highly stable, and show differential expression between nonmetastatic PCa and bone metastatic samples. Taken together, the findings underscore the importance of miRNA expression profiles and miRNA-based tools as rational technologies to increase the quality of life and longevity of patients.

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.

Anti-Inflammatory Profile of Jungia sellowii Less. by Downregulation of Proinflammatory Mediators and Inhibition of NF-κB and p38 Pathways.

Jungia sellowii Less. (Asteraceae) is a native plant found in Southeast Brazil used traditionally to treat inflammatory diseases. This study was conducted (1) to investigate the toxicity of the crude extract (CE) and (2) to investigate the mechanism of the anti-inflammatory action of J. sellowii L. roots. The potential acute toxicity of CE was performed by administration of only different doses of CE (500, 1,000, and 2,000 i.p.) on mice for 14 days. The anti-inflammatory effect was evaluated using carrageenan-induced acute pleural cavity inflammation in a mouse model, evaluated through the following inflammatory variables: leukocyte, protein concentrations of the exudate, myeloperoxidase (MPO), adenosine deaminase (ADA), nitric oxide metabolites (NOx), and proinflammatory cytokine (tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), interleukin- (IL-) 6, and IL-12) levels in mouse pleural fluid leakage. The p65 protein phosphorylation of nuclear factor NF-kappa B (p65 NF-κB) and p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation were analyzed in lung tissue. Our results demonstrated that the administration of CE up to 2,000 mg/kg did not present a toxic effect. In addition, the pretreatment of mice with CE; its derived fractions (aqueous fraction (AqF), butanol fraction (BuOHF), and ethyl acetate fraction (EtOAcF)); and isolated compounds (curcuhydroquinone O-ß-glucose (CUR) and α and ß piptizol (Pip)) reduced the following inflammatory variables: neutrophils, protein concentrations of the exudate, MPO, ADA, NOx, and proinflammatory cytokine (TNF-α, IFN-γ, IL-6, and IL-12) levels in mouse pleural fluid leakage. The compounds CUR and Pip also decreased the p65 protein phosphorylation of NF-kappa B and p38 (MAPK) in lung tissue. J. sellowii L. has important anti-inflammatory activity with potential applications in drug development against inflammatory disorders. These effects found can be attributed to the ability of the new isolated compounds CUR and Pip to suppress p65 NF-κB and p-p38 MAPK pathways.