IntroductionThe advent of anti-tumor necrosis factor alpha (anti-TNFα) drugs has considerably improved medical management in rheumatoid arthritis (RA) patients, although it has been reported to be ineffective in a fraction of them. MicroRNAs (miRNAs) are small, non-coding RNAs that act as fine-tuning regulators of gene expression. Targeting miRNAs by gain or loss of function approaches have brought therapeutic effects in various disease models. The aim of this study was to investigate serum miRNA levels as predictive biomarkers of response to anti-TNFα therapy in RA patients.MethodsIn total, 95 RA patients undergoing anti-TNFα/disease-modifying antirheumatic drugs (anti-TNFα/DMARDs) combined treatments were enrolled. Serum samples were obtained at 0 and 6 months and therapeutic efficacy was assessed. miRNAs were isolated from the serum of 10 patients before and after anti-TNFα/DMARDs combination therapy, cDNA transcribed and pooled, and human serum miRNA polymerase chain reaction (PCR) arrays were performed. Subsequently, selected miRNAs were analyzed in a validation cohort consisting of 85 RA patients. Correlation studies with clinical and serological variables were also performed.ResultsNinety percent of RA patients responded to anti-TNFα/DMARDs combination therapy according to European League Against Rheumatism (EULAR) criteria. Array analysis showed that 91% of miRNAS were overexpressed and 9% downregulated after therapy. Functional classification revealed a preponderance of target mRNAs involved in reduction of cells maturation - especially on chondrocytes - as well as in immune and inflammatory response, cardiovascular disease, connective tissue and musculoskeletal system. Six out of ten miRNAs selected for validation were found significantly upregulated by anti-TNFα/DMARDs combination therapy (miR-16-5p, miR-23-3p, miR125b-5p, miR-126-3p, miRN-146a-5p, miR-223-3p). Only responder patients showed an increase in those miRNAs after therapy, and paralleled the reduction of TNFα, interleukin (IL)-6, IL-17, rheumatoid factor (RF), and C-reactive protein (CRP). Correlation studies demonstrated associations between validated miRNAs and clinical and inflammatory parameters. Further, we identified a specific plasma miRNA signature (miR-23 and miR-223) that may serve both as predictor and biomarker of response to anti-TNFα/DMARDs combination therapy.ConclusionsmiRNA levels in the serum of RA patients before and after anti-TNFα/DMARDs combination therapy are potential novel biomarkers for predicting and monitoring therapy outcome.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-015-0555-z) contains supplementary material, which is available to authorized users.

The induction of polyploidy is considered the reproductive end of cells, but there is evidence that polyploid giant cancer cells (PGCCs) contribute to cell repopulation during tumor relapse. However, the role of these cells in the development, progression and response to therapy in colon cancer remains undefined. Therefore, the main objective of this study was to investigate the generation of PGCCs in colon cancer cells and identify mechanisms of formation. Treatment of HCT-116 and Caco-2 colon cancer cells with the hypoxia mimic CoCl2 induced the formation of cells with larger cell and nuclear size (PGCCs), while the cells with normal morphology were selectively eliminated. Cytometric analysis showed that CoCl2 treatment induced G2 cell cycle arrest and the generation of a polyploid cell subpopulation with increased cellular DNA content. Polyploidy of hypoxia-induced PGCCs was confirmed by FISH analysis. Furthermore, CoCl2 treatment effectively induced the stabilization of HIF-1α, the differential expression of a truncated form of p53 (p47) and decreased levels of cyclin D1, indicating molecular mechanisms associated with cell cycle arrest at G2. Generation of PGCCs also contributed to expansion of a cell subpopulation with cancer stem cells (CSCs) characteristics, as indicated by colonosphere formation assays, and enhanced chemoresistance to 5-fluorouracil and oxaliplatin. In conclusion, the pharmacological induction of hypoxia in colon cancer cells causes the formation of PGCCs, the expansion of a cell subpopulation with CSC characteristics and chemoresistance. The molecular mechanisms involved, including the stabilization of HIF-1 α, the involvement of p53/p47 isoform and cell cycle arrest at G2, suggest novel targets to prevent tumor relapse and treatment failure in colon cancer.

Proteomics has been used in the clam Chamaelea gallina as a preliminary screening of changes in protein expression caused by pollutants, potentially useful as new biomarkers. Clams were exposed in water for seven days to four model contaminants, Aroclor 1254, copper(II), tributyltin (TBT), and arsenic(III), and cytosolic fractions were initially analyzed by two-dimensional (2-D) electrophoresis in 7 cm IPG strips (pH 4-7). On average, about 1000 spots were resolved and altered expression was qualitatively detected in 9-26 spots per treatment. Aroclor 1254, Cu(II) and As(III) had a mainly upregulating effect, in contrast to TBT. Altered protein expression was confirmed in 18 cm gels (at narrow pH ranges). The 15 spots more drastically altered were excised and analyzed by mass spectrometry (MS), and four proteins were identified. Aroclor 1254 and Cu(II) upregulated putative isoforms of tropomyosin and light chain of myosin. Actin was downregulated by Aroclor and Cu(II) but upregulated by TBT and As(III), while the opposite behavior was shown by a truncated actin form, homologous to the Drosophila act87E gene product. The exclusive identification of cytoskeletal proteins could reflect their relative abundance, their prevalence in databases in molluscs, or their role as major targets of pollutant-related oxidative stress.

The exact mechanisms underlying the role of oxidative stress in the pathogenesis and the prothrombotic or proinflammatory status of antiphospholipid syndrome (APS) remain unknown. Here, we investigate the role of oxidative stress and mitochondrial dysfunction in the proatherothrombotic status of APS patients induced by IgG-antiphospholipid antibodies and the beneficial effects of supplementing cells with coenzyme Q 10 (CoQ 10 ). A significant increase in relevant prothrombotic and inflammatory parameters in 43 APS patients was found compared with 38 healthy donors. Increased peroxide production, nuclear abundance of Nrf2, antioxidant enzymatic activity, decreased intracellular glutathione, and altered mitochondrial membrane potential were found in monocytes and neutrophils from APS patients. Accelerated atherosclerosis in APS patients was found associated with their inflammatory or oxidative status. CoQ 10 preincubation of healthy monocytes before IgG-antiphospholipid antibody treatment decreased oxidative stress, the percentage of cells with altered mitochondrial membrane potential, and the induced expression of tissue factor, VEGF, and Flt1. In addition, CoQ 10 significantly improved the ultrastructural preservation of mitochondria and prevented IgG-APS-induced fission mediated by Drp-1 and Fis-1 proteins. In conclusion, the oxidative perturbation in APS patient leukocytes, which is directly related to an inflammatory and proatherothrombotic status, relies on alterations in mitochondrial dynamics and metabolism that may be prevented, reverted, or both by treatment with CoQ 10 .