Influence of NSAIDs and methotrexate on CD73 expression and glioma cell growth.

Glioblastoma (GBM) is the most malignant and deadly brain tumor. GBM cells overexpress the CD73 enzyme, which controls the level of extracellular adenosine, an immunosuppressive molecule. Studies have shown that some nonsteroidal anti-inflammatory drugs (NSAIDs) and methotrexate (MTX) have antiproliferative and modulatory effects on CD73 in vitro and in vivo. However, it remains unclear whether the antiproliferative effects of MTX and NSAIDS in GBM cells are mediated by increases in CD73 expression and adenosine formation. The aim of this study was to evaluate the effect of the NSAIDs, naproxen, piroxicam, meloxicam, ibuprofen, sodium diclofenac, acetylsalicylic acid, nimesulide, and ketoprofen on CD73 expression in GBM and mononuclear cells. In addition, we sought to understand whether the effects of MTX may be mediated by CD73 expression and activity. Cell viability and CD73 expression were evaluated in C6 and mononuclear cells after exposure to NSAIDs. For analysis of the mechanism of action of MTX, GBM cells were treated with APCP (CD73 inhibitor), dipyridamole (inhibitor of adenosine uptake), ABT-702 (adenosine kinase enzyme inhibitor), or caffeine (P1 adenosine receptor antagonist), before treatment with MTX and AMP, in the presence or not of mononuclear cells. In summary, only MTX increased the expression of CD73 in GBM cells decreasing cells viability by mechanisms independent of the adenosinergic system. Further studies are needed to understand the role of MTX in the GBM microenvironment.

CD73 Promotes Age-Dependent Accretion of Atherosclerosis.

OBJECTIVE: CD73 is an ectonucleotidase which catalyzes the conversion of AMP (adenosine monophosphate) to adenosine. Adenosine has been shown to be anti-inflammatory and vasorelaxant. The impact of ectonucleotidases on age-dependent atherosclerosis remains unclear. Our aim was to investigate the role of CD73 in age-dependent accumulation of atherosclerosis. Approach and results: Mice doubly deficient in CD73 and ApoE (apolipoprotein E; (cd73-/-/apoE-/-) were generated, and the extent of aortic atherosclerotic plaque was compared with apoE-/- controls at 12, 20, 32, and 52 weeks. By 12 weeks of age, cd73-/-/apoE-/- mice exhibited a significant increase in plaque (1.4±0.5% of the total vessel surface versus 0.4±0.1% in apoE-/- controls, P<0.005). By 20 weeks of age, this difference disappeared (2.9±0.4% versus 3.3±0.7%). A significant reversal in phenotype emerged at 32 weeks (9.8±1.2% versus 18.3±1.4%; P<0.0001) and persisted at the 52 week timepoint (22.4±2.1% versus 37.0±2.1%; P<0.0001). The inflammatory response to aging was found to be comparable between cd73-/-/apoE-/- mice and apoE-/- controls. A reduction in lipolysis in CD73 competent mice was observed, even with similar plasma lipid levels (cd73-/-/apoE-/- versus apoE-/- at 12 weeks [16.2±0.7 versus 9.5±1.4 nmol glycerol/well], 32 weeks [24.1±1.5 versus 7.4±0.4 nmol/well], and 52 weeks [13.8±0.62 versus 12.7±2.0 nmol/well], P<0.001). CONCLUSIONS: At early time points, CD73 exerts a subtle antiatherosclerotic influence, but with age, the pattern reverses, and the presence of CD73 promoted suppression of lipid catabolism.

Ultrasound combined with SDF-1α chemotactic microbubbles promotes stem cell homing in an osteoarthritis model.

Osteoarthritis (OA) is a common joint disease in the middle and old age group with obvious cartilage damage, and the regeneration of cartilage is the key to alleviating or treating OA. In stem cell therapy, bone marrow stem cell (BMSC) has been confirmed to have cartilage regeneration ability. However, the role of stem cells in promoting articular cartilage regeneration is severely limited by their low homing rate. Stromal cell-derived factor-1α (SDF-1α) plays a vital role in MSC migration and involves activation, mobilization, homing and retention. So, we aim to develop SDF-1α-loaded microbubbles MB(SDF-1α), and to verify the migration of BMSCs with the effect of ultrasound combined with MB(SDF-1α) in vitro and in vivo. The characteristics of microbubbles and the content of SDF-1α were examined in vitro. To evaluate the effect of ultrasound combined with chemotactic microbubbles on stem cell migration, BMSCs were injected locally and intravenously into the knee joint of the OA model, and the markers of BMSCs in the cartilage were detected. We successfully prepared MB(SDF-1α) through covalent bonding with impressive SDF-1α loading efficacy loading content. In vitro study, ultrasound combined with MB(SDF-1α) group can promote more stem cell migration with highest migrating cell counts, good cell viability and highest CXCR4 expression. In vivo experiment, more BMSCs surface markers presented in the ultrasound combined with MB(SDF-1α) group with or without exogenous BMSCs administration. Hence, ultrasound combined with MB(SDF-1α) could promote the homing of BMSCs to cartilage and provide a novel promising therapeutic approach for OA.

Adenosine receptor 2B activity promotes autonomous growth, migration as well as vascularization of head and neck squamous cell carcinoma cells.

Adenosine is a signaling molecule that exerts dual effects on tumor growth: while it inhibits immune cell function and thereby prevents surveillance by the immune system, it influences tumorigenesis directly via activation of adenosine receptors on tumor cells at the same time. However, the adenosine-mediated mechanisms affecting oncogenic processes particularly in head and neck squamous cell carcinomas (HNSCC) are not fully understood. Here, we investigated the role of adenosine receptor activity on HNSCC-derived cell lines. Targeting the adenosine receptor A2B (ADORA2B) on these cells with the inverse agonist/antagonist PSB-603 leads to inhibition of cell proliferation, transmigration as well as VEGFA secretion in vitro. At the molecular level, these effects were associated with cell cycle arrest as well as the induction of the apoptotic pathway. In addition, shRNA-mediated downmodulation of ADORA2B expression caused decreased proliferation. Moreover, in in vivo xenograft experiments, chemical and genetic abrogation of ADORA2B activity impaired tumor growth associated with decreased tumor vascularization. Together, our findings characterize ADORA2B as a crucial player in the maintenance of HNSCC and, therefore, as a potential therapeutic target for HNSCC treatment.

1α, 25-Dihydroxyvitamin D3 alters ectonucleotidase expression and activity in human cutaneous melanoma cells.

PURPOSE: We hypothesized that vitamin D decreases rates of adenosine formation in human cutaneous melanoma cells through the inhibition of extracellular adenosine 5'-triphosphate breakdown, thereby affecting tumor cell viability. Therefore, the objective of this study was to explore the mechanisms of action of 1α, 25-dihydroxyvitamin D3 (1,25(OH)2 D3) on the activity and expression of ectonucleotidases in cutaneous melanoma cells. METHODS: A human melanoma cell line, SK-Mel-28, was treated with 1 to 50 nM of the active vitamin D metabolite (1,25(OH)2 D3) over 24 hours, followed by determination of NTPDase1/CD39 and ecto-5'-nucleotidase/CD73 activity and expression rates of the purinergic system-related NTPDASE1, NT5E and adenosine deaminase and vitamin D receptor. An 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay was used to evaluate cellular viability. RESULTS: 1,25(OH)2 D3 decreased adenosine monophosphate hydrolysis via ecto-5'-nucleotidase/CD73 and expression of CD73, but did not change NTPDase1/CD39 activity; it increased the CD39 expression. We also observed an increase of cell viability at 1 nM, but this viability decreased as the concentrations of vitamin D active metabolite increased to 50 nM. There were no differences in gene expression levels. CONCLUSION: To the best of our knowledge, we showed for the first time a mechanism of control of adenosine production via modulation of the purinergic system in cutaneous melanoma cells treated with the active metabolite of vitamin D. This study provides original information regarding mechanisms, in which vitamin D plays a key role in preventing tumor progression in human melanoma cells.

Tumor CD73/A2aR adenosine immunosuppressive axis and tumor-infiltrating lymphocytes in diffuse large B-cell lymphoma: correlations with clinicopathological characteristics and clinical outcome.

Novel immune checkpoint blockades, including those targeting CD73 and A2aR, are being evaluated in malignancies in clinical trials. Here, we investigated the expression of CD73 and A2aR as well as tumor-infiltrating lymphocytes (TILs), and analyzed their correlations with clinicopathological characteristics and survival in diffuse large B-cell lymphoma (DLBCL). We found that CD73 expression on tumor cells, rather than the total protein and gene levels of CD73, was associated with survival. Patients with CD73+ /Pax-5+ (median survival, 57.8 months; 95% CI, 46.4-69.3) experienced significantly poorer outcomes than those with CD73- /Pax-5+ (median survival, 73.5 months; 95% CI, 65.9-81.2). Additionally, A2aR expression on both total TILs and CD8+ TILs was correlated with survival. Patients with A2aR+ TILs (median survival, 53.3 months; 95% CI, 40.6-66.0) had a significantly shorter survival time than patients with A2aR- TILs (median survival, 74.5 months; 95% CI, 67.5-81.5). Spearman's rank test showed that CD73 expression on tumor cells was positively correlated with A2aR expression on TILs (R = 0.395, p = 0.001). We further found that patients could be more precisely stratified through the combination of CD73 tumor cell expression and A2aR TILs expression, and patients with CD73+ /Pax-5+ and A2aR+ TILs experienced the worst outcome. We also revealed that patients with CD73+ /Pax-5+ and low CD8+ TILs or low absolute lymphocyte counts had unfavorable outcomes. Overall, our findings uncovered that patients with CD73+ on tumor cells as well as A2aR+ on TILs or low CD8+ TILs exhibited inferior survival, supporting potential combination strategies using CD73/A2aR immunosuppressive blockades as treatment options for DLBCL patients.

Gingival spheroids possess multilineage differentiation potential.

Recently studies have demonstrated HGMSCs as ideal candidates for regenerative study. Interestingly we found that HGMSCs derived spheroids are more potent and maintain the properties of stemness convincingly compared to conventional culture methods. During the culture, GMSCs instinctively accumulated into spheroids and display multipotent STRO-1 and Vimentin-positive cells. Reduced phenotypic expression of CD73, CD105, and elevated expression STRO-1 and CD-34. Pluripotent nature of S-GMSCs putatively shown the expression of OCT4A, NANOG, SOX-2, SSEA4, TRA-1-60, and TRA-181. Also, levels of protein are much higher in spheroid than dissociated culture. On endothelial induction, spheroid differentiated and developed a vascular structure with positive expression of CD31 and on neuronal induction showed positivity for TUJ1 and E-Cadherin. Importantly, undifferentiated state of S-GMSCs exhibited significant upregulation of aforementioned pluripotent genes and lack of pro-inflammatory cytokines IL-6 and amplified ARF signal confirming that the spheroids are not teratoma formation. However, higher of CAP1, CP, TGFß, OPN, PPARÉ£, TUJ1, and NESTIN expression observed in spheroids, and minimal expression of the same markers were observed in adherent GMSCs respectively. Ahead of dissociated gingival culture, spheroid provides enhanced viable, pluripotent, and multilineage ability. This study suggested that S-GMSCs increased the chances of therapeutic efficacy in the regenerative applications.

Characterization of ecto-nucleotidases in human oviducts with an improved approach simultaneously identifying protein expression and in situ enzyme activity.

Extracellular ATP and its hydrolysis product adenosine modulate various reproductive functions such as those taking place in oviducts, including contraction, beating of cilia, and maintenance of fluid composition that, in turn, influences sperm capacitation and hyperactivation, as well as oocyte and embryo nourishing. Ecto-nucleotidases are the enzymes that regulate extracellular ATP and adenosine levels, thus playing a role in reproduction. We have optimized a convenient method for characterizing ecto-nucleotidases that simultaneously localizes the protein and its associated enzyme activity in the same tissue slice and characterizes ecto-nucleotidases in human oviducts. The technique combines immunofluorescence and in situ histochemistry, allowing precise identification of ecto-nucleotidases at a subcellular level. In oviducts, remarkably, ectonucleoside triphosphate diphosphohydrolase 2 (NTPDase2) and NTPDase3, with the ability to hydrolyze ATP to AMP, are expressed in ciliated epithelial cells but with different subcellular localization. Ecto-5'nucleotidase/CD73 is also expressed apically in ciliated cells. CD73, together with alkaline phosphatase, also expressed apically in oviductal epithelium, complete the hydrolysis sequence by dephosphorylating AMP to adenosine. The concerted action of these enzymes would contribute to the local increase of adenosine concentration necessary for sperm capacitation. The use of this method would be an asset for testing new potential therapeutic drugs with inhibitory potential, which is of great interest presently in the field of oncology and in other clinical disciplines.

An Elf2-like transcription factor acts as repressor of the mouse ecto-5'-nucleotidase gene expression in hepatic myofibroblasts.

Hepatic fibrosis represents a pathological wound healing and tissue repair process triggered in response to chronic liver injury. A heterogeneous population of activated non-parenchymal liver cells, known as liver myofibroblasts, functions as the effector cells in hepatic fibrosis. Upon activation, liver myofibroblasts become fibrogenic, acquiring contractile properties and increasing collagen production capacity, while developing enhanced sensitivity to endogenous molecules and factors released in the local microenvironment. Hepatic extracellular adenosine is a bioactive small molecule, increasingly recognized as an important regulator of liver myofibroblast functions, and an important mediator in the pathogenesis of liver fibrosis overall. Remarkably, ecto-5'-nucleotidase/Nt5e/Cd73 enzyme, which accounts for the dominant adenosine-generating activity in the extracellular medium, is expressed by activated liver myofibroblasts. However, the molecular signals regulating Nt5e gene expression in liver myofibroblasts remain poorly understood. Here, we show that activated mouse liver myofibroblasts express Nt5e gene products and characterize the putative Nt5e minimal promoter in the mouse species. We describe the existence of an enhancer sequence upstream of the mouse Nt5e minimal promoter and establish that the mouse Nt5e minimal promoter transcriptional activity is negatively regulated by an Elf2-like Ets-related transcription factor in activated mouse liver myofibroblasts.

CD56brightCD16- NK Cells Produce Adenosine through a CD38-Mediated Pathway and Act as Regulatory Cells Inhibiting Autologous CD4+ T Cell Proliferation.

Recent studies suggested that human CD56(bright)CD16(-) NK cells may play a role in the regulation of the immune response. Since the mechanism(s) involved have not yet been elucidated, in the present study we have investigated the role of nucleotide-metabolizing enzymes that regulate the extracellular balance of nucleotides/nucleosides and produce the immunosuppressive molecule adenosine (ADO). Peripheral blood CD56(dim)CD16(+) and CD56(bright)CD16(-) NK cells expressed similar levels of CD38. CD39, CD73, and CD157 expression was higher in CD56(bright)CD16(-) than in CD56(dim)CD16(+) NK cells. CD57 was mostly expressed by CD56(dim)CD16(+) NK cells. CD203a/PC-1 expression was restricted to CD56(bright)CD16(-) NK cells. CD56(bright)CD16(-) NK cells produce ADO and inhibit autologous CD4(+) T cell proliferation. Such inhibition was 1) reverted pretreating CD56(bright)CD16(-) NK cells with a CD38 inhibitor and 2) increased pretreating CD56(bright)CD16(-) NK cells with a nucleoside transporter inhibitor, which increase extracellular ADO concentration. CD56(bright)CD16(-) NK cells isolated from the synovial fluid of juvenile idiopathic arthritis patients failed to inhibit autologous CD4(+) T cell proliferation. Such functional impairment could be related to 1) the observed reduced CD38/CD73 expression, 2) a peculiar ADO production kinetics, and 3) a different expression of ADO receptors. In contrast, CD56(bright)CD16(-) NK cells isolated from inflammatory pleural effusions display a potent regulatory activity. In conclusion, CD56(bright)CD16(-) NK cells act as "regulatory cells" through ADO produced by an ectoenzymes network, with a pivotal role of CD38. This function may be relevant for the modulation of the immune response in physiological and pathological conditions, and it could be impaired during autoimmune/inflammatory diseases.

Global genomic and transcriptomic analysis of human pancreatic islets reveals novel genes influencing glucose metabolism.

Genetic variation can modulate gene expression, and thereby phenotypic variation and susceptibility to complex diseases such as type 2 diabetes (T2D). Here we harnessed the potential of DNA and RNA sequencing in human pancreatic islets from 89 deceased donors to identify genes of potential importance in the pathogenesis of T2D. We present a catalog of genetic variants regulating gene expression (eQTL) and exon use (sQTL), including many long noncoding RNAs, which are enriched in known T2D-associated loci. Of 35 eQTL genes, whose expression differed between normoglycemic and hyperglycemic individuals, siRNA of tetraspanin 33 (TSPAN33), 5'-nucleotidase, ecto (NT5E), transmembrane emp24 protein transport domain containing 6 (TMED6), and p21 protein activated kinase 7 (PAK7) in INS1 cells resulted in reduced glucose-stimulated insulin secretion. In addition, we provide a genome-wide catalog of allelic expression imbalance, which is also enriched in known T2D-associated loci. Notably, allelic imbalance in paternally expressed gene 3 (PEG3) was associated with its promoter methylation and T2D status. Finally, RNA editing events were less common in islets than previously suggested in other tissues. Taken together, this study provides new insights into the complexity of gene regulation in human pancreatic islets and better understanding of how genetic variation can influence glucose metabolism.

Methotrexate up-regulates ecto-5'-nucleotidase/CD73 and reduces the frequency of T lymphocytes in the glioblastoma microenvironment.

Glioblastoma multiforme (GBM) is a deadly cancer characterized by a pro-tumoral immune response. T-regulatory (Treg) lymphocytes suppress effector immune cells through cytokine secretion and the adenosinergic system. Ecto-5'-nucleotidase/CD73 plays a crucial role in Treg-mediated immunosuppression in the GBM microenvironment (GME). Methotrexate (MTX) is an immunosuppressive drug that can increase the extracellular concentration of adenosine. In this manuscript, C6 GBM cells were treated with 1.0 µM MTX, and ecto-5'-nucleotidase/CD73 expression and extracellular AMP metabolism were analyzed in vitro. For in vivo studies, rats with implanted GBM were treated for 10 days with MTX-loaded lipid-core nanocapsules (MTX-LNCs, 1 mg/kg/day). The activity of ectonucleotidase and the expression of NTPDase1/CD39 and ecto-5'-nucleotidase/CD73 were measured. The frequencies of T lymphocytes (CD3(+)CD4(+), CD3(+)CD8(+), and CD4(+)CD25(high)CD39(+)) were quantified. In vitro, treatment with MTX increased CD73 expression and activity in C6 cells, which is in agreement with higher levels of extracellular adenosine. In vivo, MTX-LNC treatment increased CD39 expression on CD3(+)CD8(+) lymphocytes. In addition, MTX-LNC treatment up-regulated CD73 expression in tissue isolated from GBM, a finding that is in agreement with the higher activity of this enzyme. More specifically, the treatment increased CD73 expression on CD3(+)CD4(+) and CD3(+)CD8(+) lymphocytes. Treatment with MTX-LNCs decreased the frequencies of T-cytotoxic, T-helper, and Treg lymphocytes in the GME. Although more studies are necessary to better understand the complex cross-talk mediated by supra-physiological concentrations of adenosine in the GME, these studies demonstrate that MTX treatment increases CD73 enzyme expression and AMP hydrolysis, leading to an increase in adenosine production and immunosuppressive capability.

Identification of a distinct subpopulation of fibroblasts from murine dermis: CD73(-) CD105(+) as potential marker of dermal fibroblasts subset with multipotency.

Skin dermis includes various types of multipotent stromal cells (MSCs) and a subpopulation of dermal fibroblasts that exhibit the ability to differentiate. However, characterization of this dermal fibroblast subtype remains less understood. In this study, we isolated dermal cells from the skin of newborn C57/B6 mice and investigated their characteristics. Isolated murine dermal cells exhibited a fibroblast phenotype as judged by accepted criteria including a lack of MSC-related antigens and the differentiation potential of MSCs, and the positive expression of fibroblast markers. A comparative analysis demonstrated that CD73(-) CD105(+) but not CD73(-) CD105(-) dermal fibroblasts exhibited some of the functional properties of MSCs. Furthermore, the multipotent phenotype of CD73(-) CD105(+) cells was diminished by treatment of CD105 siRNA and shRNA, indicating that CD105 expression was critical for the retention of differentiation potential of those cells. Overall, these results suggest that CD73(-) CD105(+) cells are a distinct subset of dermal fibroblasts with multipotency and that their surface antigens could help to classify this subpopulation. These cells may contribute to the regeneration of damaged tissue.

Role of TGF-ß signaling in generation of CD39+CD73+ myeloid cells in tumors.

There is growing evidence that generation of adenosine from ATP, which is mediated by the CD39/CD73 enzyme pair, predetermines immunosuppressive and proangiogenic properties of myeloid cells. We have previously shown that the deletion of the TGF-ß type II receptor gene (Tgfbr2) expression in myeloid cells is associated with decreased tumor growth, suggesting protumorigenic effect of TGF-ß signaling. In this study, we tested the hypothesis that TGF-ß drives differentiation of myeloid-derived suppressor cells into protumorigenic terminally differentiated myeloid mononuclear cells (TDMMCs) characterized by high levels of cell-surface CD39/CD73 expression. We found that TDMMCs represent a major cell subpopulation expressing high levels of both CD39 and CD73 in the tumor microenvironment. In tumors isolated from mice with spontaneous tumor formation of mammary gland and conditional deletion of the type II TGF-ß receptor in mammary epithelium, an increased level of TGF-ß protein was associated with further increase in number of CD39(+)CD73(+) TDMMCs compared with MMTV-PyMT/TGFßRII(WT) control tumors with intact TGF-ß signaling. Using genetic and pharmacological approaches, we demonstrated that the TGF-ß signaling mediates maturation of myeloid-derived suppressor cells into TDMMCs with high levels of cell surface CD39/CD73 expression and adenosine-generating capacity. Disruption of TGF-ß signaling in myeloid cells resulted in decreased accumulation of TDMMCs, expressing CD39 and CD73, and was accompanied by increased infiltration of T lymphocytes, reduced density of blood vessels, and diminished progression of both Lewis lung carcinoma and spontaneous mammary carcinomas. We propose that TGF-ß signaling can directly induce the generation of CD39(+)CD73(+) TDMMCs, thus contributing to the immunosuppressive, proangiogenic, and tumor-promoting effects of this pleiotropic effector in the tumor microenvironment.

CD73 promotes anthracycline resistance and poor prognosis in triple negative breast cancer.

Using gene-expression data from over 6,000 breast cancer patients, we report herein that high CD73 expression is associated with a poor prognosis in triple-negative breast cancers (TNBC). Because anthracycline-based chemotherapy regimens are standard treatment for TNBC, we investigated the relationship between CD73 and anthracycline efficacy. In TNBC patients treated with anthracycline-only preoperative chemotherapy, high CD73 gene expression was significantly associated with a lower rate of pathological complete response or the disappearance of invasive tumor at surgery. Using mouse models of breast cancer, we demonstrated that CD73 overexpression in tumor cells conferred chemoresistance to doxorubicin, a commonly used anthracycline, by suppressing adaptive antitumor immune responses via activation of A2A adenosine receptors. Targeted blockade of CD73 enhanced doxorubicin-mediated antitumor immune responses and significantly prolonged the survival of mice with established metastatic breast cancer. Taken together, our data suggest that CD73 constitutes a therapeutic target in TNBC.

Characteristics of Multipotent Mesenchymal Stromal Cells Isolated from Human Endometrium.

Cell cultures isolated from human endometrium by enzyme digestion consisted of highly viable fibroblast-like mesenchymal cells expressing CD90, CD73, and CD105. During passage 1, the cultures contained a small fraction of cytokeratin-7(+) epithelial cells that disappeared by passage 2. The cultures from the endometrium could be induced to adipogenic, osteogenic and chondrogenic differentiation in vitro. These findings suggest that human endometrium is a convenient source of biomaterial for minimally invasive isolation of cultures that exhibit typical morphology and immunophenotypic profile of resident multipotent mesenchymal stromal cells retain high viability in vitro.

Novel serology testing for sporadic inclusion body myositis: disease-specificity and diagnostic utility.

PURPOSE OF REVIEW: The purpose of this article is to discuss recent advances in serological testing for sporadic inclusion body myositis (sIBM) and to provide a review of their diagnostic utility and disease-specificity of auto-antibodies in sIBM. RECENT FINDINGS: The identification, prevalence and diagnostic utility of a new auto-antibody targeting cytosolic 5'-nucleotidase 1A (cN-1A) in the serum of sIBM patients have recently been published. These studies have shown that anti-cN-1A auto-antibodies have diagnostic utility for differentiating sIBM from other forms of myositis and from other neuromuscular diseases. Anti-cN-1A-positive patient sera are directed to multiple epitopes of cN-1A and contain, in addition to IgG, IgA and IgM, anti-cN-1A auto-antibodies. Recent studies have also shown a relatively high prevalence of these auto-antibodies in sera form Sjögren's syndrome and systemic lupus erythematosus patients. SUMMARY: The recent discovery of auto-antibodies to cN-1A provides a serological tool to aid the differentiation between inflammatory myopathies and supports the idea that apart from degeneration, an adaptive immune response may also play a role in sIBM pathophysiology. Future research will need to focus on standardization of methods to detect these auto-antibodies in order to further explore their specificity and diagnostic utility for sIBM.

Kindlin-2 regulates hemostasis by controlling endothelial cell-surface expression of ADP/AMP catabolic enzymes via a clathrin-dependent mechanism.

Kindlin-2, a widely distributed cytoskeletal protein, has been implicated in integrin activation, and its absence is embryonically lethal in mice. In the present study, we tested whether hemostasis might be perturbed in kindlin-2(+/-) mice. Bleeding time and carotid artery occlusion time were significantly prolonged in kindlin-2(+/-) mice. Whereas plasma concentrations/activities of key coagulation/fibrinolytic proteins and platelet counts and aggregation were similar in wild-type and kindlin-2(+/-) mice, kindlin-2(+/-) endothelial cells (ECs) showed enhanced inhibition of platelet aggregation induced by adenosine 5'-diphosphate (ADP) or low concentrations of other agonists. Cell-surface expression of 2 enzymes involved in ADP/adenosine 5'-monophosphate (AMP) degradation, adenosine triphosphate (ATP) diphosphohydrolase (CD39) and ecto-5'-nucleotidase (CD73) were increased twofold to threefold on kindlin-2(+/-) ECs, leading to enhanced ATP/ADP catabolism and production of adenosine, an inhibitor of platelet aggregation. Trafficking of CD39 and CD73 at the EC surface was altered in kindlin-2(+/-) mice. Mechanistically, this was attributed to direct interaction of kindlin-2 with clathrin heavy chain, thereby controlling endocytosis and recycling of CD39 and CD73. The interaction of kindlin-2 with clathrin was independent of its integrin binding site but still dependent on a site within its F3 subdomain. Thus, kindlin-2 regulates trafficking of EC surface enzymes that control platelet responses and hemostasis.

The expression and clinical significance of CD73 molecule in human rectal adenocarcinoma.

The ectonucleotidase CD73 degrades adenosine triphosphate (ATP) to adenosine which potently inhibits host immune responses against cancer. This study investigated the expression level and prognostic significance of CD73 in human rectal adenocarcinoma. Our data demonstrated that CD73 staining strongly marked both malignant epithelial cells and stromal components where the protein and messenger RNA (mRNA) expression levels of CD73 were significantly increased compared with paracancerous controls. High CD73 expression in tumor cells can be used as an independent factor for predicting poor patients' prognosis; however, patients with higher density of stromal CD73 were more likely to have favorable characteristics (early T and tumor-node-metastasis (TNM) stages) and overall survival. Notably, combined CD73 expression analysis in both tumoral and stromal compartments was more efficient to foretell patient's outcome where patients with increased CD73 in tumor cells but decreased CD73 in stroma displayed a worst prognosis. Taken together, the current study revealed CD73 expression was increased in both tumoral and stromal compartments. Although upregulated CD73 expression in tumor cells correlates with a poor prognosis in patients with rectal adenocarcinoma, the combination of CD73 expression in malignant epithelial cells and tumor stroma may have a better prognostic value.

High expression of CD39/ENTPD1 in malignant epithelial cells of human rectal adenocarcinoma.

The ectonucleotidase CD39 is pivotal in the conversion of immunostimulatory adenosine triphosphate (ATP) into immunosuppressive adenosine which potently inhibits host immune responses against cancer. This study investigated the expression level and prognostic significance of CD39 in human rectal adenocarcinoma. Our data demonstrated that CD39 staining strongly marked malignant epithelial cells where the protein and messenger RNA (mRNA) expression levels of CD39 were significantly increased compared with paracancerous controls. In addition to primary tumors, CD39 was also abundantly expressed in liver metastases and tumor-draining lymph nodes from metastatic rectal adenocarcinoma. Although patients with higher CD39 density in tumor cells were more likely to have favorable characteristics (early TNM and N stages) and overall survival, the singular parameter cannot be used as an independent factor for predicting patients' prognosis. Intriguingly, combined analysis of CD39 and CD73 expression was more efficient to foretell patient's outcome where patients with increased CD73 but decreased CD39 levels displayed a worst prognosis. Taken together, the current study revealed that malignant epithelial cells of human rectal adenocarcinoma strongly express CD39 that may play a potential role in the tumor invasion and metastasis. Although high expression of CD39 in tumor cells is correlated with favorable clinical outcome, the combination of CD39 and CD73 expression may have a better prognostic value.