Impact of Methylated Cyclodextrin KLEPTOSE® CRYSMEB on Inflammatory Responses in Human In Vitro Models.

KLEPTOSE® CRYSMEB methylated cyclodextrin derivative displays less methylated group substitution than randomly methylated cyclodextrin. It has demonstrated an impact on atherosclerosis and neurological diseases, linked in part to cholesterol complexation and immune response, however, its impact on inflammatory cascade pathways is not clear. Thus, the impact of KLEPTOSE® CRYSMEB on various pharmacological targets was assessed using human umbilical vein endothelial cells under physiological and inflammatory conditions, followed by screening against twelve human primary cell-based systems designed to model complex human tissue and disease biology of the vasculature, skin, lung, and inflammatory tissues using the BioMAP® Diversity PLUS® panel. Finally, its anti-inflammatory mechanism was investigated on peripheral blood mononuclear cells to evaluate anti-inflammatory or pro-resolving properties. The results showed that KLEPTOSE® CRYSMEB can modulate the immune system in vitro and potentially manage vascular issues by stimulating the expression of molecules involved in the crosstalk between immune cells and other cell types. It showed anti-inflammatory effects that were driven by the inhibition of pro-inflammatory cytokine secretion and could have different impacts on different tissue types. Moreover, this cyclodextrin showed no clear impact on pro-resolving lipid mediators. Additionally, it appeared that the mechanism of action of KLEPTOSE® CRYSMEB seems to not be shared by other well-known anti-inflammatory molecules. Finally, KLEPTOSE® CRYSMEB may have an anti-inflammatory impact, which could be due to its effect on receptors such as TLR or direct complexation with LPS or PGE2, and conversely, this methylated cyclodextrin could stimulate a pro-inflammatory response involving lipid mediators and on proteins involved in communication with immune cells, probably via interaction with membrane cholesterol.

FVIII regulates the molecular profile of endothelial cells: functional impact on the blood barrier and macrophage behavior.

Hemophilia A is an inherited X-linked recessive bleeding disorder caused by deficient activity of blood coagulation factor VIII (FVIII). In addition, hemophilia patients show associated diseases including osteopenia, altered inflammation and vascular fragility which may represent the consequence of recurrent bleeding or may be related to the direct FVIII deficiency. Nowadays, recombinant FVIII is proposed to treat hemophilia patients with no circulating FVIII inhibitor. Initially described as a coenzyme to factor IXa for initiating thrombin generation, there is emerging evidence that FVIII is involved in multiple biological systems, including bone, vascular and immune systems. The present study investigated: (i) the functional activities of recombinant human FVIII (rFVIII) on endothelial cells, and (ii) the impact of rFVIII activities on the functional interactions of human monocytes and endothelial cells. We then investigated whether rFVIII had a direct effect on the adhesion of monocytes to the endothelium under physiological flow conditions. We observed that direct biological activities for rFVIII in endothelial cells were characterized by: (i) a decrease in endothelial cell adhesion to the underlying extracellular matrix; (ii) regulation of the transcriptomic and protein profiles of endothelial cells; (iii) an increase in the vascular tubes formed and vascular permeability in vitro; and (iv) an increase in monocyte adhesion activated endothelium and transendothelial migration. By regulating vascular permeability plus leukocyte adhesion and transendothelial migration, the present work highlights new biological functions for FVIII.

The Unitary Micro-Immunotherapy Medicine Interferon-γ (4 CH) Displays Similar Immunostimulatory and Immunomodulatory Effects than Those of Biologically Active Human Interferon-γ on Various Cell Types.

As a cytokine, gamma-interferon (IFN-γ) is considered a key player in the fine-tuned orchestration of immune responses. The extreme cellular sensitivity to cytokines is attested by the fact that very few of these bioactive molecules per cell are enough to trigger cellular functions. These findings can, at least partially, explain how/why homeopathically-prepared cytokines, and especially micro-immunotherapy (MI) medicines, are able to drive cellular responses. We focused our fundamental research on a unitary MI preparation of IFN-γ, specifically employed at 4 CH, manufactured and impregnated onto sucrose-lactose pillules as all other MI medicines. We assessed the IFN-γ concentration in the medium after dilution of the IFN-γ (4 CH)-bearing pillules and we evaluated in vitro drug responses in a wide range of immune cells, and in endothelial cells. Our results showed that IFN-γ (4 CH) stimulated the proliferation, the activation and the phagocytic capabilities of primary immune cells, as well as modulated their cytokine-secretion and immunity-related markers' expression in a trend that is quite comparable with the well-recognized biological effects induced by IFN-γ. Altogether, these data provide novel and additional evidences on MI medicines, and specifically when active substances are prepared at 4 CH, thus suggesting the need for more investigations.

A Micro-Immunotherapy Sequential Medicine MIM-seq Displays Immunomodulatory Effects on Human Macrophages and Anti-Tumor Properties towards In Vitro 2D and 3D Models of Colon Carcinoma and in an In Vivo Subcutaneous Xenograft Colon Carcinoma Model.

In this study, the immunomodulatory effects of a sequential micro-immunotherapy medicine, referred as MIM-seq, were appraised in human primary M1 and M2 macrophages, in which the secretion of pro-inflammatory cytokines, such as interleukin (IL)-1ß, IL-6, IL-12, IL-23, and tumor necrosis factor (TNF)-alpha, was inhibited. In addition, the potential anti-proliferative effects of MIM-seq on tumor cells was assessed in three models of colorectal cancer (CRC): an in vitro two-dimensions (2D) model of HCT-116 cells, an in vitro tri-dimensional (3D) model of spheroids, and an in vivo model of subcutaneous xenografted mice. In these models, MIM-seq displayed anti-proliferative effects when compared with the vehicle. In vivo, the tumor growth was slightly reduced in MIM-seq-treated animals. Moreover, MIM-seq could slightly reduce the growth of our spheroid models, especially under serum-deprivation. When MIM-seq was combined with two well-known anti-cancerogenic agents, either resveratrol or etoposide, MIM-seq could even further reduce the spheroid's volume, pointing up the need to further assess whether MIM-seq could be beneficial for CRC patients as an adjuvant therapy. Altogether, these data suggest that MIM-seq could have anti-tumor properties against CRC and an immunomodulatory effect towards the mediators of inflammation, whose systemic dysregulation is considered to be a poor prognosis for patients.

The Micro-Immunotherapy Medicine 2LEID Exhibits an Immunostimulant Effect by Boosting Both Innate and Adaptive Immune Responses.

This study aimed at evaluating the effects of the micro-immunotherapy medicine (MIM) 2LEID, both in vitro and in vivo, on several components of the innate and adaptive immune system. MIM increased the phagocytic activity of macrophages, and it augmented the expression of the activation markers CD69 and HLA-DR in NK cells and monocytes/macrophages, respectively. The effect of MIM was evaluated in a model of respiratory infection induced by influenza A virus administration to immunocompetent mice in which it was able to improve neutrophil recruitment within the lungs (p = 0.1051) and slightly increased the circulating levels of IgM (p = 0.1655). Furthermore, MIM stimulated the proliferation of CD3-primed T lymphocytes and decreased the secretion of the immunosuppressive cytokine IL-10 in CD14+-derived macrophages. Human umbilical vein endothelial cells were finally used to explore the effect of MIM on endothelial cells, in which it slightly increased the expression of immune-related markers such as HLA-I, CD137L, GITRL, PD-L1 and ICAM-1. In conclusion, the present study suggests that MIM might be a promising nonspecific (without antigen specificity) immunostimulant drug in preventing and early treating respiratory infections, but not only exclusively, as it would gently support several facets of the immune system and host defenses.

In vitro and in vivo discrepancy in inducing apoptosis by mesenchymal stromal cells delivering membrane-bound tumor necrosis factor-related apoptosis inducing ligand in osteosarcoma pre-clinical models.

BACKGROUND: Osteosarcoma (OS) is the most frequent pediatric malignant bone tumor. OS patients have not seen any major therapeutic progress in the last 30 years, in particular in the case of metastatic disease, which requires new therapeutic strategies. The pro-apoptotic cytokine Tumor necrosis factor (TNF)-Related Apoptosis Inducing Ligand (TRAIL) can selectively kill tumor cells while sparing normal cells, making it a promising therapeutic tool in several types of cancer. However, many OS cell lines appear resistant to recombinant human (rh)TRAIL-induced apoptosis. We, therefore, hypothesized that TRAIL presentation at the membrane level of carrier cells might overcome this resistance and trigger apoptosis. METHODS: To address this, human adipose mesenchymal stromal cells (MSCs) transfected in a stable manner to express membrane-bound full-length human TRAIL (mbTRAIL) were co-cultured with several human OS cell lines. RESULTS: This induced apoptosis by cell-to-cell contact even in cell lines initially resistant to rhTRAIL. In contrast, mbTRAIL delivered by MSCs was not able to counteract tumor progression in this OS orthotopic model. DISCUSSION: This was partly due to the fact that MSCs showed a potential to support tumor development. Moreover, the expression of mbTRAIL did not show caspase activation in adjacent tumor cells.

TRAIL delivered by mesenchymal stromal/stem cells counteracts tumor development in orthotopic Ewing sarcoma models.

Ewing sarcoma (EWS) is the second most frequent pediatric malignant bone tumor. EWS patients have not seen any major therapeutic progress in the last 30 years, in particular in the case of metastatic disease, which requires new therapeutic strategies. The pro-apoptotic cytokine TNF-Related Apoptosis Inducing Ligand (TRAIL) can selectively kill tumor cells while sparing normal cells, making it a promising therapeutic tool in several types of cancer. However, certain EWS cell lines appear resistant to recombinant human (rh) TRAIL-induced apoptosis. We therefore hypothesized that a TRAIL presentation at the surface of the carrier cells might overcome this resistance and trigger apoptosis. For this purpose, human adipose mesenchymal stromal/stem cells (MSC) transfected in a stable manner to express full-length human TRAIL were co-cultured with several human EWS cell lines, inducing apoptosis by cell-to-cell contact even in cell lines initially resistant to rhTRAIL or AMG655, an antibody agonist to the death receptor, DR5. In vivo, TRAIL delivered by MSCs was able to counteract tumor progression in two orthotopic models of Ewing sarcoma, associated with caspase activation, indicating that a cell-based delivery of a potent apoptosis-inducing factor could be relevant in EWS.

IL-1ß and TNFα promote monocyte viability through the induction of GM-CSF expression by rheumatoid arthritis synovial fibroblasts.

BACKGROUND: Macrophages and synovial fibroblasts (SF) are two major cells implicated in the pathogenesis of rheumatoid arthritis (RA). SF could be a source of cytokines and growth factors driving macrophages survival and activation. Here, we studied the effect of SF on monocyte viability and phenotype. METHODS: SF were isolated from synovial tissue of RA patients and CD14+ cells were isolated from peripheral blood of healthy donors. SF conditioned media were collected after 24 hours of culture with or without stimulation with TNFα or IL-1ß. Macrophages polarisation was studied by flow cytometry. RESULTS: Conditioned medium from SF significantly increased monocytes viability by 60% compared to CD14+ cells cultured in medium alone (P < 0.001). This effect was enhanced using conditioned media from IL-1ß and TNFα stimulated SF. GM-CSF but not M-CSF nor IL34 blocking antibodies was able to significantly decrease monocyte viability by 30% when added to the conditioned media from IL-1ß and TNFα stimulated SF (P < 0.001). Finally, monocyte cultured in presence of SF conditioned media did not exhibit a specific M1 or M2 phenotype. CONCLUSION: Overall, rheumatoid arthritis synovial fibroblasts stimulated with proinflammatory cytokines (IL-1ß and TNFα) promote monocyte viability via GM-CSF but do not induce a specific macrophage polarization.

MICA variant promotes allosensitization after kidney transplantation.

MHC class I-related chain A (MICA) antigens are surface glycoproteins strongly implicated in innate immunity, and the MICA gene is highly polymorphic. Clinical observations suggest a role for donor MICA antigens expressed on transplant endothelial cells in the alloimmune response, but the effect of MICA genotype is not well understood. Here, we investigated the immunologic effect of the A5.1 mutation, related to the common MICA*008 allele. Compared with wild-type endothelial cells (ECs), homozygosity for MICA A5.1 associated with an endothelial phenotype characterized by 7- to 10-fold higher levels of MICA mRNA and MICA proteins at the cell surface, as well as exclusive release in exosomes instead of enzymatic cleavage. Mechanistically, we did not detect quantitative changes in regulatory microRNAs. Functionally, A5.1 ECs enhanced NKG2D interaction and natural killer cell activation, promoting NKG2D-dependent lysis of ECs. In kidney transplant recipients, polyreactive anti-MICA sera bound preferentially to ECs from MICA A5.1 donors, suggesting that MICA*008(A5.1) molecules are the preferential antigenic determinants on ECs of grafts. Furthermore, the incidence of MICA A5.1 mismatch revealed a statistically significant association between donor MICA A5.1 and both anti-MICA sensitization and increased proteinuria in kidney recipients. Taken together, these results identify the A5.1 mutation as an immunodominant factor and a potential risk factor for transplant survival.

The promises of PCSK9 inhibition.

PURPOSE OF REVIEW: In the past 10 years, the LDL receptor inhibitor proprotein convertase subtilisin kexin type 9 (PCSK9) has emerged as a validated target for lowering plasma LDL cholesterol levels. Here we review the most recent reports on PCSK9 out of a total of 500 publications published in print or online before March 2013 and indexed on PubMed. RECENT FINDINGS: All published in 2012, phase I and II clinical trials demonstrate that fully human monoclonal antibodies targeting PCSK9 dramatically reduce LDL-C and enable patients to reach their target goals, without severe or serious safety issues. SUMMARY: This review summarizes the discovery of PCSK9, its original mode of action as a secreted inhibitor of the LDL receptor, as well as its genetic regulation by statins. We then focus on the major results from the 2012 phase I and II PCSK9 inhibitor clinical trials. We also review the recent in-vivo studies demonstrating the potential cardiovascular benefits of long-term PCSK9 inhibition and discuss its potential side-effects.

Actives from the Micro-Immunotherapy Medicine 2LMIREG® Reduce the Expression of Cytokines and Immune-Related Markers Including Interleukin-2 and HLA-II While Modulating Oxidative Stress and Mitochondrial Function.

Introduction: Micro-immunotherapy (MI) is a therapeutic option employing low doses (LD) and ultra-low doses (ULD) of cytokines and immune factors to help the organism at modulating the immune responses. In an overpowering inflammatory context, this strategy may support the restoration of the body's homeostasis, as the active ingredients of MI medicines' (MIM) could boost or slow down the physiological functions of the immune cells. The aim of the study is to evaluate for the first time the in vitro anti-inflammatory properties of some actives employed by the MIM of interest in several human immune cell models. Methods: In the first part of the study, the effects of the actives from the MIM of interest were assessed from a molecular standpoint: the expression of HLA-II, interleukin (IL)-2, and the secretion of several other cytokines were evaluated. In addition, as mitochondrial metabolism is also involved in the inflammatory processes, the second part of the study aimed at assessing the effects of these actives on the mitochondrial reactive oxygen species (ROS) production and on the mitochondrial membrane potential. Results: We showed that the tested actives decreased the expression of HLA-DR and HLA-DP in IFN-γ-stimulated endothelial cells and in LPS-treated-M1-macrophages. The tested MIM slightly reduced the intracellular expression of IL-2 in CD4+ and CD8+ T-cells isolated from PMA/Iono-stimulated human PBMCs. Additionally, while the secretion of IL-2, IL-10, and IFN-γ was diminished, the treatment increased IL-6, IL-9, and IL-17A, which may correspond to a "Th17-like" secretory pattern. Interestingly, in PMA/Iono-treated PBMCs, we reported that the treatment reduced the ROS production in B-cells. Finally, in PMA/Iono-treated human macrophages, we showed that the treatment slightly protected the cells from early cell death/apoptosis. Discussion: Overall, these results provide data about the molecular and functional anti-inflammatory effects of several actives contained in the tested MIM in immune-related cells, and their impact on two mitochondria-related processes.

Understanding the Mode of Action of a Micro-Immunotherapy Formulation: Pre-Clinical Evidence from the Study of 2LEBV® Active Ingredients.

BACKGROUND: Epstein-Barr virus (EBV) is often kept silent and asymptomatic; however, its reactivation induces a chronic and/or recurrent infection that is associated with numerous diseases, including cancer and inflammation-related disorders. As no specific treatment is currently available, the immune factors-based micro-immunotherapy (MI) medicine 2LEBV® could be considered a valuable therapeutic option to sustain the immune system in EBV reactivation. METHODS: The present work aimed to investigate, for the first time, the effect of 2LEBV® in several in vitro models of uninfected immune-related cells. RESULTS: 2LEBV® displayed phagocytosis-enhancing capabilities in granulocytes. In human peripheral blood mononuclear cells (PBMCs), it increased the intra- and extra-cellular expression of interleukin (IL)-2. Moreover, it modulated the secretion of other cytokines, increasing IL-4, IL-6, and tumor necrosis factor-α levels or lowering other cytokines levels such as IL-9. Finally, 2LEBV® reduced the expression of human leukocyte antigen (HLA)-II in endothelial cells and macrophages. CONCLUSIONS: Although these data are still preliminary and the chosen models do not consider the underlying EBV-reactivation mechanisms, they still provide a better understanding of the mechanisms of action of 2LEBV®, both at functional and molecular levels. Furthermore, they open perspectives regarding the potential targets of 2LEBV® in its employment as a therapeutic intervention for EBV-associated diseases.

The Micro-Immunotherapy Medicine 2LPAPI® Displays Immune-Modulatory Effects in a Model of Human Papillomavirus Type-16 L1-Protein Capsid-Treated Human Peripheral Blood Mononuclear Cells and Antiproliferative Effects in a Model of Cervical Cancer Cells.

Human papillomavirus (HPV) is the second most common infectious agent causing cancer. Persistent infection with high-risk (HR)-HPV can lead to cervical intra-epithelial neoplasia and cervical carcinomas (CC). While host immune response is necessary for viral clearance, chronic immune activation contributes to a low-grade inflammation that can ultimately lead to carcinogenesis. The micro-immunotherapy medicine (MIM) 2LPAPI® could be a valuable tool to manage the clearance of the virus and reduce the risk of developing CC. In this in vitro study, we aimed to investigate its mode of action. We showed that actives from the MIM increased the IL-6, IFN-γ, and IP-10 secretion in human peripheral blood mononuclear cells (PBMCs) exposed to peptides derived from the HPV-16 capsid (HPV16(L1)). This could reflect an increase in the immune activity toward HPV-16. At the same time, some active substances reduced the lympho-proliferation and the expression of T-cell activation markers. Finally, some of the MIM actives displayed antiproliferative effects in CC-derived HeLa cells under serum-starvation conditions. Altogether, this body of data highlighted for the first time the dual effect of MIM in the framework of HR-HPV infections as a potential (i) immune modulator of HPV16(L1)-treated PBMCs and (ii) antiproliferative agent of HPV-positive CC cells.

In Vitro Study of Interleukin-6 when Used at Low Dose and Ultra-Low Dose in Micro-Immunotherapy.

As one of the major cytokines implicated in the orchestration of immune responses, interleukin 6 (IL-6) can either act as a pro- or an anti-inflammatory factor, depending on the micro-environment. In micro-immunotherapy (MI) medicines, IL-6 is employed at low doses (LD) and ultra-low doses (ULD), expressed in centesimal Hahnemannian (CH), and used alone or in combination with other immune regulators to modulate patients' immune responses. The present study focused on assessing the in vitro immune-modulatory effects of two IL-6-containing MI products: (i) the unitary IL-6 (4 CH) and (ii) the complex MI-medicine (MIM) 2LALERG®, which includes IL-6 (17 CH) in association with other actives in its formulation. Our results showed that IL-6 (4 CH) activated granulocytes under basal conditions, and natural killer cells in the presence of an anti-CD3 signal, as assessed by their CD69 expression. In addition, IL-6 (4 CH) balanced the macrophages' differentiation toward a M2a profile. On the other hand, the tested 2LALERG® capsule inhibited the histamine degranulation of rats' peritoneal mast cells and reduced the release of IL-6 itself in inflamed human macrophages. Altogether, these data provide novel pieces of evidence on the double-edged potential of the LD and ULD of IL-6 in immune responses modulation, when employed in MI.

LNK (SH2B3) is a key regulator of integrin signaling in endothelial cells and targets α-parvin to control cell adhesion and migration.

Focal adhesion (FA) formation and disassembly play an essential role in adherence and migration of endothelial cells. These processes are highly regulated and involve various signaling molecules that are not yet completely identified. Lnk [Src homology 2-B3 (SH2B3)] belongs to a family of SH2-containing proteins with important adaptor functions. In this study, we showed that Lnk distribution follows that of vinculin, localizing Lnk in FAs. Inhibition of Lnk by RNA interference resulted in decreased spreading, whereas sustained expression dramatically increases the number of focal and cell-matrix adhesions. We demonstrated that Lnk expression impairs FA turnover and cell migration and regulates ß1-integrin-mediated signaling via Akt and GSK3ß phosphorylation. Moreover, the α-parvin protein was identified as one of the molecular targets of Lnk responsible for impaired FA dynamics and cell migration. Finally, we established the ILK protein as a new molecular partner for Lnk and proposed a model in which Lnk regulates α-parvin expression through its interaction with ILK. Collectively, our results underline the adaptor Lnk as a novel and effective key regulator of integrin-mediated signaling controlling endothelial cell adhesion and migration.

Gene transfer of the adaptor Lnk (SH2B3) prevents porcine endothelial cell activation and apoptosis: implication for xenograft's cytoprotection.

BACKGROUND: Targeting protective gene expression to porcine endothelium by genetic modification of the donor could improve xenograft survival by controlling cell activation and death. We previously found that, in endothelial cells (EC), the molecular adaptor Lnk (SH2B3) is a negative regulator of cytokine signaling. We also have shown that Lnk is upregulated in pig EC (PAEC) in response to tumor necrosis factor-α (TNF) and xenoreactive natural antibodies (XNA) binding. The present study investigated whether ectopic expression of human Lnk using gene transfer may be efficient to control signaling pathways associated with inflammation and apoptosis in porcine aortic endothelial cells (PAEC). METHODS: Endothelial cells cultures were established from WT and Gal(-/-) pigs and transduced with a recombinant adenovirus encoding human Lnk. Phenotype and functions of transduced PAEC expressing Lnk were analyzed by flow cytometry, western blot and XNA and complement-dependent assays. The regulatory functions of Lnk toward inflammation were assessed in TNF-activated EC, and the protective functions were tested toward TNF-induced apoptosis and anoïkis. Apoptosis assays included DNA content analysis and caspase-3/7 activity. RESULTS: First, we found that as a result of adenoviral transduction, human Lnk was efficiently and similarly expressed in EC from WT or Gal(-/-) pigs. Lnk expression or EC transduction caused no significant change in the binding of XNA (IgG and IgM) to PAEC and has no effect on complement activation and C5b-9 formation. We demonstrated that expression of human Lnk efficiently inhibits TNF signaling in PAEC and decreases VCAM-1 induction by 46.3 ± 1.2% compared to controls (n = 6, **P < 0.01). Furthermore, expression of Lnk was associated with a significant decrease in the percentage of caspase-3/7-dependent apoptosis caused by TNF in the presence of actinomycin D and also reduces cell death by anoïkis by 25.0 ± 1.9% compared to controls (n = 5, **P < 0.01). CONCLUSIONS: Together, these findings indicate that the signaling adaptor Lnk is effective to reduce PAEC activation and apoptosis. Thus, Lnk is a potential candidate for the modulation of signaling pathways to protect vascular EC from inflammation in xenotransplantation.

Evaluation of the Chemotherapy Drug Response Using Organotypic Cultures of Osteosarcoma Tumours from Mice Models and Canine Patients.

Improvements in the clinical outcome of osteosarcoma have plateaued in recent decades with poor translation between preclinical testing and clinical efficacy. Organotypic cultures retain key features of patient tumours, such as a myriad of cell types organized within an extracellular matrix, thereby presenting a more realistic and personalised screening of chemotherapeutic agents ex vivo. To test this concept for the first time in osteosarcoma, murine and canine osteosarcoma organotypic models were maintained for up to 21 days and in-depth analysis identified proportions of immune and stromal cells present at levels comparable to that reported in vivo in the literature. Cytotoxicity testing of a range of chemotherapeutic drugs (mafosfamide, cisplatin, methotrexate, etoposide, and doxorubicin) on murine organotypic culture ex vivo found limited response to treatment, with immune and stromal cells demonstrating enhanced survival over the global tumour cell population. Furthermore, significantly decreased sensitivity to a range of chemotherapeutics in 3D organotypic culture relative to 2D monolayer was observed, with subsequent investigation confirming reduced sensitivity in 3D than in 2D, even at equivalent levels of drug uptake. Finally, as proof of concept for the application of this model to personalised drug screening, chemotherapy testing with doxorubicin was performed on biopsies obtained from canine osteosarcoma patients. Together, this study highlights the importance of recapitulating the 3D tumour multicellular microenvironment to better predict drug response and provides evidence for the utility and possibilities of organotypic culture for enhanced preclinical selection and evaluation of chemotherapeutics targeting osteosarcoma.

Implication of molecular vascular smooth muscle cell heterogeneity among arterial beds in arterial calcification.

Vascular calcification is a strong and independent predictive factor for cardiovascular complications and mortality. Our previous work identified important discrepancies in plaque composition and calcification types between carotid and femoral arteries. The objective of this study is to further characterize and understand the heterogeneity in vascular calcification among vascular beds, and to identify molecular mechanisms underlying this process. We established ECLAGEN biocollection that encompasses human atherosclerotic lesions and healthy arteries from different locations (abdominal, thoracic aorta, carotid, femoral, and infrapopliteal arteries) for histological, cell isolation, and transcriptomic analysis. Our results show that lesion composition differs between these locations. Femoral arteries are the most calcified arteries overall. They develop denser calcifications (sheet-like, nodule), and are highly susceptible to osteoid metaplasia. These discrepancies may derive from intrinsic differences between SMCs originating from these locations, as microarray analysis showed specific transcriptomic profiles between primary SMCs isolated from each arterial bed. These molecular differences translated into functional disparities. SMC from femoral arteries showed the highest propensity to mineralize due to an increase in basal TGFß signaling. Our results suggest that biological heterogeneity of resident vascular cells between arterial beds, reflected by our transcriptomic analysis, is critical in understanding plaque biology and calcification, and may have strong implications in vascular therapeutic approaches.

L-MTP-PE and zoledronic acid combination in osteosarcoma: preclinical evidence of positive therapeutic combination for clinical transfer.

Osteosarcoma, the most frequent malignant primary bone tumor in pediatric patients is characterized by osteolysis promoting tumor growth. Lung metastasis is the major bad prognosis factor of this disease. Zoledronic Acid (ZA), a potent inhibitor of bone resorption is currently evaluated in phase III randomized studies in Europe for the treatment of osteosarcoma and Ewing sarcoma. The beneficial effect of the liposomal form of Muramyl-TriPeptide-Phosphatidyl Ethanolamine (L-mifamurtide, MEPACT®), an activator of macrophage populations has been demonstrated to eradicate lung metastatic foci in osteosarcoma. The objective of this study was to evaluate the potential therapeutic benefit and the safety of the ZA and L-mifamurtide combination in preclinical models of osteosarcoma, as a prerequisite before translation to patients. The effects of ZA (100 µg/kg) and L-mifamurtide (1 mg/kg) were investigated in vivo in xenogeneic and syngeneic mice models of osteosarcoma, at clinical (tumor proliferation, spontaneous lung metastases development), radiological (bone microarchitecture by microCT analysis), biological and histological levels. No interference between the two drugs could be observed on ZA-induced bone protection and on L-mifamurtide-induced inhibition of lung metastasis development. Unexpectedly, ZA and L-mifamurtide association induced an additional and in some cases synergistic inhibition of primary tumor progression. L-mifamurtide has no effect on tumor proliferation in vitro or in vivo, and macrophage population was not affected at the tumor site whatever the treatment. This study evidenced for the first time a significant inhibition of primary osteosarcoma progression when both drugs are combined. This result constitutes a first proof-of-principle for clinical application in osteosarcoma patients.

Osteoprotegerin, pericytes and bone-like vascular calcification are associated with carotid plaque stability.

BACKGROUND AND PURPOSE: Vascular calcification, recapitulating bone formation, has a profound impact on plaque stability. The aim of the present study was to determine the influence of bone-like vascular calcification (named osteoid metaplasia = OM) and of osteoprotegerin on plaque stability. METHODS: Tissue from carotid endarterectomies were analysed for the presence of calcification and signs of vulnerability according to AHA grading system. Osteoprotegerin (OPG), pericytes and endothelial cells were sought using immuno-histochemistry. Symptoms and preoperative imaging findings (CT-scan, MRI and Doppler-scan) were analyzed. Human pericytes were cultured to evaluate their ability to secrete OPG and to influence mineralization in the plaque. RESULTS: Seventy-three carotid plaques (49 asymptomatic and 24 symptomatic) were harvested. A significantly higher presence of OM (18.4% vs 0%, p<0.01), OPG (10.2% of ROI vs 3.4% of ROI, p<0.05) and pericytes (19% of ROI vs 3.8% of ROI, p<0.05) were noted in asymptomatic compared to symptomatic plaques. Consistently, circulating OPG levels were higher in the plasma of asymptomatic patients (3.2 ng/mL vs 2.5 ng/mL, p = 0.05). In vitro, human vascular pericytes secreted considerable amounts of OPG and underwent osteoblastic differentiation. Pericytes also inhibited the osteoclastic differentiation of CD14+ cells through their secretion of OPG. CONCLUSIONS: OPG (intraplaque an plasmatic) and OM are associated with carotid plaque stability. Pericytes may be involved in the secretion of intraplaque OPG and in the formation of OM.