Targeting FOXP3 Tumor-Intrinsic Effects Using Adenoviral Vectors in Experimental Breast Cancer.

The regulatory T cell master transcription factor, Forkhead box P3 (Foxp3), has been detected in cancer cells; however, its role in breast tumor pathogenesis remains controversial. Here we assessed Foxp3 tumor intrinsic effects in experimental breast cancer using a Foxp3 binder peptide (P60) that impairs Foxp3 nuclear translocation. Cisplatin upregulated Foxp3 expression in HER2+ and triple-negative breast cancer (TNBC) cells. Foxp3 inhibition with P60 enhanced chemosensitivity and reduced cell survival and migration in human and murine breast tumor cells. We also developed an adenoviral vector encoding P60 (Ad.P60) that efficiently transduced breast tumor cells, reduced cell viability and migration, and improved the cytotoxic response to cisplatin. Conditioned medium from transduced breast tumor cells contained lower levels of IL-10 and improved the activation of splenic lymphocytes. Intratumoral administration of Ad.P60 in breast-tumor-bearing mice significantly reduced tumor infiltration of Tregs, delayed tumor growth, and inhibited the development of spontaneous lung metastases. Our results suggest that Foxp3 exerts protumoral intrinsic effects in breast cancer cells and that gene-therapy-mediated blockade of Foxp3 could constitute a therapeutic strategy to improve the response of these tumors to standard treatment.

Mitochondrial Peptide Humanin Facilitates Chemoresistance in Glioblastoma Cells.

Humanin (HN) is a mitochondrial-derived peptide with robust cytoprotective effects in many cell types. Although the administration of HN analogs has been proposed to treat degenerative diseases, its role in the pathogenesis of cancer is poorly understood. Here, we evaluated whether HN affects the chemosensitivity of glioblastoma (GBM) cells. We found that chemotherapy upregulated HN expression in GBM cell lines and primary cultures derived from GBM biopsies. An HN analog (HNGF6A) boosted chemoresistance, increased the migration of GBM cells and improved their capacity to induce endothelial cell migration and proliferation. Chemotherapy also upregulated FPR2 expression, an HN membrane-bound receptor, and the HNGF6A cytoprotective effects were inhibited by an FPR2 receptor antagonist (WRW4). These effects were observed in glioma cells with heterogeneous genetic backgrounds, i.e., glioma cells with wild-type (wtIDH) and mutated (mIDH) isocitrate dehydrogenase. HN silencing using a baculoviral vector that encodes for a specific shRNA for HN (BV.shHN) reduced chemoresistance, and impaired the migration and proangiogenic capacity of GBM cells. Taken together, our findings suggest that HN boosts the hallmark characteristics of GBM, i.e., chemoresistance, migration and endothelial cell proliferation. Thus, strategies that inhibit the HN/FPR2 pathway may improve the response of GBM to standard therapy.

Potential role of fibroblast-like synoviocytes in joint damage induced by Brucella abortus infection through production and induction of matrix metalloproteinases.

Arthritis is one of the most common complications of human brucellosis, but its pathogenic mechanisms have not been elucidated. Fibroblast-like synoviocytes (FLS) are known to be central mediators of joint damage in inflammatory arthritides through the production of matrix metalloproteinases (MMPs) that degrade collagen and of cytokines and chemokines that mediate the recruitment and activation of leukocytes. In this study we show that Brucella abortus infects and replicates in human FLS (SW982 cell line) in vitro and that infection results in the production of MMP-2 and proinflammatory mediators (interleukin-6 [IL-6], IL-8, monocyte chemotactic protein 1 [MCP-1], and granulocyte-macrophage colony-stimulating factor [GM-CSF]). Culture supernatants from Brucella-infected FLS induced the migration of monocytes and neutrophils in vitro and also induced these cells to secrete MMP-9 in a GM-CSF- and IL-6-dependent fashion, respectively. Reciprocally, culture supernatants from Brucella-infected monocytes and neutrophils induced FLS to produce MMP-2 in a tumor necrosis factor alpha (TNF-α)-dependent fashion. The secretion of proinflammatory mediators and MMP-2 by FLS did not depend on bacterial viability, since it was also induced by heat-killed B. abortus (HKBA) and by a model Brucella lipoprotein (L-Omp19). These responses were mediated by the recognition of B. abortus antigens through Toll-like receptor 2. The intra-articular injection of HKBA or L-Omp19 into the knee joint of mice resulted in the local induction of the proinflammatory mediators MMP-2 and MMP-9 and in the generation of a mixed inflammatory infiltrate. These results suggest that FLS, and phagocytes recruited by them to the infection focus, may be involved in joint damage during brucellar arthritis through the production of MMPs and proinflammatory mediators.

Treatment With Platelet Lysate Inhibits Proteases of Synovial Fluid in Equines With Osteoarthritis.

Osteoarthritis (OA) is the most prevalent arthropathy in sport horses. The administration of a platelet lysate (PL) is an alternative method for the treatment of musculoskeletal conditions. The mechanisms by which PL exerts its beneficial effects have not been determined, and less is known about its effect on the activity of the proteolytic enzymes of the synovial fluid of equines with OA. In this work, the effect of the administration of PL to horses with OA was analyzed both clinically and molecularly by determining the levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5), glycosaminoglycans (GAGs), and tissue inhibitor of metalloproteinase 1 (TIMP-1) in synovial fluid. One mL of PL was administered intra-articularly followed by the extraction of synovial fluid on days 0, 10, 30, and 60. Results were evaluated by an analysis of variance for repeated measures. The levels of MMP-9 decreased significantly (P < .05) on day 10 after treatment with PL. A disintegrin and metalloproteinase with thrombospondin motifs 5 decreased significantly on days 10 (P < .05), 30 (P < .05), and 60 (P < .01) after treatment. The levels of synovial TIMP-1 increased significantly on day 30 (P < .001) after treatment. Glycosaminoglycans showed a significant increase on days 10 (P < .05) and 30 (P < .01). A significant decrease was found for MMP-2 on day 10 (P < .01), 30 (P < .01), and 60 (P < .001). In conclusion, the beneficial effects of PL in OA could be attributed to the decreased activity of MMP-2, MMP-9, and ADAMTS-5 and the increased concentration of GAGs and TIMP-1 after the administration of platelet-rich plasma.

Prolactin and its receptor as therapeutic targets in glioblastoma multiforme.

Although prolactin (PRL) and its receptor (PRLR) have been detected in glioblastoma multiforme (GBM), their role in its pathogenesis remains unclear. Our aim was to explore their contribution in GBM pathogenesis. We detected PRL and PRLR in all GBM cell lines tested. PRLR activation or overexpression using plasmid transfection increased proliferation, viability, clonogenicity, chemoresistance and matrix metalloproteinase activity in GBM cells, while PRLR antagonist ∆1-9-G129R-hPRL reduced their proliferation, viability, chemoresistance and migration. Meta-analysis of transcriptomic data indicated that PRLR was expressed in all grade II-III glioma (GII-III) and GBM samples. PRL was upregulated in GBM biopsies when compared to GII-III. While in the general population tumour PRL/PRLR expression did not correlate with patient survival, biological sex-stratified analyses revealed that male patients with PRL+/PRLRHIGH GBM performed worse than PRL+/PRLRLOW GBM. In contrast, all male PRL+/PRLRHIGH GII-III patients were alive whereas only 30% of PRL+/PRLRLOW GII-III patients survived after 100 months. Our study suggests that PRLR may be involved in GBM pathogenesis and could constitute a therapeutic target for its treatment. Our findings also support the notion that sexual dimorphism should be taken into account to improve the care of GBM patients.

Development of ELISAs for the measurement of IgM and IgG subclasses in sera from llamas (Lama glama) and assessment of the humoral immune response against different antigens.

Members of the Camelidae family possess a functional class of antibodies devoid of light chains (known as heavy chain antibodies, HCAbs). Three IgG isotypes have been identified (IgG(1), IgG(2) and IgG(3)); IgG(2) and IgG(3) are HCAbs whereas the IgG(1) has the conventional structure. Different subtypes of IgG(1) (IgG(1a) and IgG(1b)) and IgG(2) (IgG(2a), IgG(2b) and IgG(2c)) have been classified according to variations in the amino acids sequence of the hinge region. The single variable domain of HCAbs has been referred as VHH. Until now, the relative amount of each subclass has been inferred, but the lack of highly specific antibodies against HCAbs has been a limitation for their quantification. In a previous work, we produced specific polyclonal antibodies against IgG(2a), IgG(2b), IgG(2c) and IgG(3) by immunizing rabbits with synthetic and recombinant peptides corresponding to their hinge region. In this work we produced specific antisera against llama IgM and IgG(1). The anti-IgG(1) serum was obtained by immunizing rabbits with a recombinant fusion protein formed by GST fused to the CH(1) domain of the IgG(1). The anti-IgM serum was obtained by immunizing rabbits with IgM heavy chain. All these antisera were useful for the development of ELISAs for the measurement of IgM, total IgG and IgG subclasses. Sera from llamas (n=20) analyzed by ELISA gave the following values of immunoglobulins: IgG(1)=6.168+/-1.628 mg/ml; IgG(2)=0.684+/-0.310 mg/ml; IgG(3)=1.232+/-0.410 mg/ml; total IgG=8.933+/-1.815 mg/ml and IgM=1.027+/-0.308 mg/ml. These results indicate that HCAbs represent almost 25% of total IgG and the IgG(3) subtype is the predominant HCAb. We also analyzed the primary humoral immune response after immunization llamas with different antigens (BSA, BSA-DNP and dextran). Although it has been described that a few VHH clones are very efficient in the interaction with haptens, in this case the response against DNP was characterized by a delayed appearance of HCAbs in comparison with that of IgG(1). No anti-dextran response was observed in any of the isotypes analyzed.

A novel and easy method for the production of recombinant peptides for use in the generation of monospecific antisera against Lama glama IgG2b and IgG2c subclasses.

We describe an easy method for the production of small recombinant peptides of 8 amino acid residues expressed as a fusion peptide with glutathione S-transferase (GST) and employed in an immunisation schedule to obtain polyclonal antibodies. The chosen peptides corresponded to specific fragments of the hinge regions of llama (Lama glama) IgG2 subisotypes b (2bH) and c (2cH). The DNA sequences encoding each peptide were ligated individually into pGEX-5X-2, which encodes GST. Once purified from a bacterial lysate by glutathione affinity chromatography, GST-2bH and GST-2cH were used to immunize rabbits. In parallel, polyclonal antibodies were generated against specific synthetic fragments of the hinge regions of llama IgG2a (2aH) and IgG3 (3H) coupled to keyhole limpet haemocyanin (KLH). Polyclonal antibodies raised against GST-peptides and KLH-peptides were detected by enzyme-linked immunosorbent assay (ELISA), Western blot (WB) and indirect immunofluorescence (IIF). The results obtained by ELISA demonstrated that monospecific anti-IgG2 and anti-IgG3 antisera were obtained using KLH-2aH, GST-2bH, GST-2cH and KLH-3H as antigens. All antisera showed reactivity with their specific IgG isotype by WB and IIF. This simple and novel recombinant DNA methodology for the generation of two monospecific anti-isotype antisera using small peptides expressed as fusion peptides with GST offers the possibility of large scale peptide production as an alternative to chemical peptide synthesis.

Structural analysis of effector functions related motifs, complement activation and hemagglutinating activities in Lama glama heavy chain antibodies.

Heavy chain antibodies (HCAbs), devoid of the light chains and the CH(1) domain, are present in the serum of camelids. IgG(2) and IgG(3) are HCAbs; whereas IgG(1) has the conventional structure. In order to study the immunological properties of llama HCAbs, from which to date little is known, llamas (Lama glama) HCAbs cDNA were cloned, sequenced and compared with other mammalian Igs. The sequence analysis showed that llama HCAbs cDNA organization is similar to other mammalian Igs and the presence of conserved binding motifs to Protein A, Protein G, FcγRI, FcγRIII and C1q in HCAbs were observed. In a previous work, different IgG isotypes purified by Protein A and Protein G chromatography, were assayed for their ability to fix complement. Both IgG(1) and the total serum were able to fix complement, whereas IgG(2) and IgG(3) fixed complement even in the absence of antigen (anti-complementary activity). Therefore, in this work we performed the complement activating activity of the different IgG isotypes purified under physiological conditions using Sephadex G-150 and their ability to induce hemagglutination. Llamas were immunized with sheep red blood cells (RBC) stroma and the different isotypes were purified from sera. Whole serum and IgG(1) could activate complement; however, HCAbs (IgG(2)+IgG(3)) could not, despite the presence of the C1q binding motif in their primary sequence. Unlike IgG(1), the fraction corresponding to IgG(2)+IgG(3) did not display hemagglutinating activity. Our findings suggest that HCAbs cannot crosslink efficiently with different antigens and that the C1q binding site might be hindered by the proximity of the variable domains.

Efecto del alendronato sobre el perfil de citoquinas y metaloproteinasas 2 y 9 en un modelo múrido de artritis experimental / Alendronate effects on cytokines and metalloproteases 2 and 9 profiles in an experimental arthritis murine model

Resumen Introducción: La artritis es una de las artropatías más frecuentes, se caracteriza por el daño que produce en el cartílago articular y la resorción ósea subcondral. El diagnóstico temprano es de crucial importancia para instaurar una terapia preventiva, ya que, en ocasiones, la enfermedad es diagnosticada al presentarse lesiones óseas de difícil resolución. Objetivos: Caracterizar, en un modelo múrido de artritis experimental producida por adyuvante, el perfil de distintos biomarcadores articulares, interleuquinas (IL-4, IL-6 y TNF-a) y metaloproteasas (MMP-2 y MMP-9), que permitan seguir la evolución de la enfermedad y analizar sus diferencias, al aplicar el tratamiento con alendronato en forma preventiva o curativa. Materiales y métodos: El alendronato, en forma preventiva, se aplicó el día 0 y de manera curativa a los dos meses posadyuvante. Se realizó un puntaje de los síntomas clínicos; al sacrificio, se determinaron los marcadores articulares y se realizaron los estudios histopatológicos y radiográficos. Resultados: Lo más destacable fue que el grupo que recibió el alendronato, de manera preventiva, alcanzó un puntaje clínico normal de manera más temprana que el grupo control con adyuvante. Asimismo, los animales tratados con alendronato presentaron valores significativamente más bajos de metaloproteasas. Conclusiones: Nuestros resultados sugieren que, aparentemente, el alendronato disminuye la actividad de proteasas vinculadas a la fisiopatología de la enfermedad articular, lo cual podría resultar sumamente beneficioso para la terapéutica a instaurar.

Abstract Introduction: Arthritis is one of the most common arthropathies, characterized by cartilage damage associated with subchondral bone resorption. Early diagnosis is crucial for the prevention of subchondral bone lesions. Objectives: To use an experimental adjuvant arthritis rat model, to measure joint biomarkers, interleukins (IL-4, IL-6 and TNF-a), and metalloproteases (MMP-2 and MMP-9) to follow the progression of the disease and to analyze the possible changes in the different treatment groups, with preventive or curative alendronate. Materials and methods: Preventive alendronate was applied on day 0, and a curative regimen 2 months post-adjuvant. A clinical scale score was used for characterizing clinical symptoms, and, at sacrifice, joint biomarkers and histopathological and radiographic studies were determined. Results: The most notable result was that the group that received preventive alendronate reached a normal clinical score faster than control adjuvant group. All alendronate groups showed significantly lower MMPs levels. Conclusions: Alendronate apparently decreases proteases activity linked to the pathophysiology of joint disease, this could be extremely beneficial for the clinical outcome of arthritis.