Extracellular vesicles-associated miRNAs in triple-negative breast cancer: from tumor biology to clinical relevance.

Breast cancer (BC), a heterogeneous group of diseases, is the most frequent type and the leading cause of cancer-related death among women worldwide. Tumor heterogeneity directly impacts cancer progression and treatment, as evidenced by the patients´ diverse prognosis and treatment responses across the distinct molecular subtypes. Triple-negative breast cancer (TNBC), which accounts for 10-20% of all diagnosed BC cases, is an aggressive BC subtype with a challenging prognosis. Current treatment options include systemic chemotherapy and/or target therapies based on PARP and PD-L1 inhibitors for eligible patients. MicroRNAs (miRNAs) are important regulatory non-coding RNAs (ncRNAs) in TNBC tumorigenesis. These molecules are present both intracellularly and released into biofluids, packaged into extracellular vesicles (EVs). Emerging evidence indicates that EVs-associated miRNAs (EVs-miRNAs), transferred from parental to recipient cells, are key mediators of cell-to-cell communication. Considering their stability and abundance in several biofluids, these molecules may reflect the epigenomic composition of their tumors of origin and contribute to mediate tumorigenesis, similar to their intracellular counterparts. This review provides the current knowledge on EVs-miRNAs in the TNBC subtype, focusing on their role in regulating mRNA targets involved in tumor phenotypes and their clinical relevance as promising biomarkers in liquid biopsies.

MiRNAs Action and Impact on Mitochondria Function, Metabolic Reprogramming and Chemoresistance of Cancer Cells: A Systematic Review.

MicroRNAs (miRNAs) are involved in the regulation of mitochondrial function and homeostasis, and in the modulation of cell metabolism, by targeting known oncogenes and tumor suppressor genes of metabolic-related signaling pathways involved in the hallmarks of cancer. This systematic review focuses on articles describing the role, association, and/or involvement of miRNAs in regulating the mitochondrial function and metabolic reprogramming of cancer cells. Following the PRISMA guidelines, the articles reviewed were published from January 2010 to September 2022, with the search terms "mitochondrial microRNA" and its synonyms (mitochondrial microRNA, mitochondrial miRNA, mito microRNA, or mitomiR), "reprogramming metabolism," and "cancer" in the title or abstract). Thirty-six original research articles were selected, revealing 51 miRNAs with altered expression in 12 cancers: bladder, breast, cervical, colon, colorectal, liver, lung, melanoma, osteosarcoma, pancreatic, prostate, and tongue. The actions of miRNAs and their corresponding target genes have been reported mainly in cell metabolic processes, mitochondrial dynamics, mitophagy, apoptosis, redox signaling, and resistance to chemotherapeutic agents. Altogether, these studies support the role of miRNAs in the metabolic reprogramming hallmark of cancer cells and highlight their potential as predictive molecular markers of treatment response and/or targets that can be used for therapeutic intervention.

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.

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.

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.

N-phenylmaleimides affect adipogenesis and present antitumor activity through reduction of FASN expression.

In light of the evidence that in contrast to most healthy tissues, several neoplasms overexpress fatty acid synthase (FASN) upon their dependence on increased lipogenesis; targeting of this protein is being considered as a valuable strategy in anticancer drug development. This can be particularly relevant for aggressive tumors such as melanoma in which FASN overexpression has been associated with increased depth of invasion and worse prognosis. We have previously shown that a sub-class of cyclic imides, the N-phenylmaleimides, presented antitumor activity against L1210 leukemia and B16F10 melanoma with evidences of interference in the energetic metabolism. Here, we aimed to investigate if some selected N-phenylmaleimides (M1 and M5) interfere with fatty acids metabolism and its relation with cancer. For that, a model of pre-adipocytes differentiation (3T3-L1 cells) and also human melanoma cells (SK-Mel-147) were used. As results, when 3T3-L1 cells were exposed to non-cytotoxic concentrations of M1 and M5 in the presence of an adipogenic cocktail, intracellular lipid content decreased by 26-36%, marking the inhibition of adipocyte differentiation. High selectivity indexes were obtained for both compounds for tumoral cells. Cell cycle phases analysis revealed a remarkable proportion of cells with DNA fragmentation after their exposure to M1 and M5. This was correlated to both apoptosis and necrosis, showed by Annexin-V/PI assay. Furthermore, M1 and M5 reduced FASN expression by 19-39%, respectively. In conclusion, M1 and M5 presented antiadipogenic and antitumoral activities. The antitumoral activity that was associated to apoptosis and necrosis is a possible consequence of the FASN reduction, which in turn, might result in a fuel decrease to cell proliferation. As it happens with antiangiogenic activity, reduction of fatty acid synthesis might be a potential target for cancer treatment in a strategy of hunger-strike, which valorizes these N-phenylmaleimides as candidates for drug development.

Intracellular ROS Generation Mediates Maleimide-induced Cytotoxicity in Leukemia Cells.

Maleimides consist of an important class of compounds easily synthesized with multiple functional group modification that provides expressive pharmacological properties including, antitumoral activity, mediated mainly by oxidative stress. For this reason, the present study was designed to evaluate the cytotoxicity and the role of reactive oxygen species (ROS) in maleimide-induced cell death. Cell viability assays were performed to determine the cell death type in leukemia cell line induced by the compounds. The oxidative stress in maleimidetreated cells was characterized by antioxidant enzymes activities, intracellular ROS generation, and lipid peroxidation. In addition, we evaluated mitochondrial membrane potential and ATP level. Maleimide derivatives exhibited cytotoxic effects in leukemia cells with significantly increased ROS generation. However, cell viability was partly restored by catalase-treated cells. Caspases activities and caspase-independent key genes related to apoptosis were not altered by maleimides, suggesting necrosis as the main cell death process. Maleimide-induced necrosis was associated with oxidative stress, as an imbalance between ROS levels and glutathione reductase (GR) activity. This damage was also demonstrated by loss of mitochondrial membrane potential (MMP) and ATP depletion in cells treated with maleimide derivatives. These findings strongly confirmed that maleimide derivatives promoted cell death in leukemia cells triggered by oxidative stress, indicating that these compounds might be promising antitumor agents or lead molecules.