Hypoximimetic activity of N-acyl-dopamines. N-arachidonoyl-dopamine stabilizes HIF-1α protein through a SIAH2-dependent pathway.

The N-acyl conjugates of amino acids and neurotransmitters (NAANs) are a class of endogenous lipid messengers that are expressed in the mammalian central and peripheral nervous system. Hypoxia inducible factor-1α (HIF-1α) is a transcription factor that plays a key role in the cellular adaptation to hypoxia and ischemia, and hypoxic preconditioning through HIF-1α has been shown to be neuroprotective in ischemic models. This study showed that N-acyl-dopamines induce HIF-1α stabilization on human primary astrocytes and neurons as well as in transformed cell lines. N-arachidonoyl-dopamine (NADA)-induced HIF-1α stabilization depends on the dopamine moiety of the molecule and is independent of cannabinoid receptor-1 (CB1) and transient receptor potential vanilloid type I (TRPV1) activation. NADA increases the activity of the E3 ubiquitin ligase seven in absentia homolog-2 (SIAH2), inhibits prolyl-hydroxylase-3 (PHD3) and stabilizes HIF-1α. NADA enhances angiogenesis in endothelial vascular cells and promotes the expression of genes such as erythropoietin (EPO), vascular endothelial growth factor A (VEGFA), heme oxygenase 1 (HMOX-1), hexokinase 2 (HK2) and Bcl-2/E1B-nineteen kiloDalton interacting protein (BNIP3) in primary astrocytes. These findings indicate a link between N-acyl-dopamines and hypoxic preconditioning and suggest that modulation of the N-acyl-dopamine metabolism might prove useful for prevention against hypoxic diseases.

Suppression of metastatic organ colonization and antiangiogenic activity of the orally bioavailable lipid raft-targeted alkylphospholipid edelfosine.

Metastasis is the leading cause of cancer mortality. Metastatic cancer is notoriously difficult to treat, and it accounts for the majority of cancer-related deaths. The ether lipid edelfosine is the prototype of a family of synthetic antitumor compounds collectively known as alkylphospholipid analogs, and its antitumor activity involves lipid raft reorganization. In this study, we examined the effect of edelfosine on metastatic colonization and angiogenesis. Using non-invasive bioluminescence imaging and histological examination, we found that oral administration of edelfosine in nude mice significantly inhibited the lung and brain colonization of luciferase-expressing 435-Lung-eGFP-CMV/Luc metastatic cells, resulting in prolonged survival. In metastatic 435-Lung and MDA-MB-231 breast cancer cells, we found that edelfosine also inhibited cell adhesion to collagen-I and laminin-I substrates, cell migration in chemotaxis and wound-healing assays, as well as cancer cell invasion. In 435-Lung and other MDA-MB-435-derived sublines with different organotropism, edelfosine induced G2/M cell cycle accumulation and apoptosis in a concentration- and time-dependent manner. Edelfosine also inhibited in vitro angiogenesis in human and mouse endothelial cell tube formation assays. The antimetastatic properties were specific to cancer cells, as edelfosine had no effects on viability in non-cancerous cells. Edelfosine accumulated in membrane rafts and endoplasmic reticulum of cancer cells, and membrane raft-located CD44 was downregulated upon drug treatment. Taken together, this study highlights the potential of edelfosine as an attractive drug to prevent metastatic growth and organ colonization in cancer therapy. The raft-targeted drug edelfosine displays a potent activity against metastatic organ colonization and angiogenesis, two major hallmarks of tumor malignancy.

CD89 Is a Potent Innate Receptor for Bacteria and Mediates Host Protection from Sepsis.

Direct bacterial recognition by innate receptors is crucial for bacterial clearance. Here, we show that the IgA receptor CD89 is a major innate receptor that directly binds bacteria independently of its cognate ligands IgA and c-reactive protein (CRP). This binding is only partially inhibited by serum IgA and induces bacterial phagocytosis by CD11c+ dendritic cells and monocytes and/or macrophages, suggesting a physiological role in innate host defense. Blood phagocytes from common variable immunodeficiency patients bind, internalize, and kill bacteria in a CD89-dependent manner, confirming the IgA independence of this mechanism. In vivo, CD89 transgenic mice are protected in two different models of sepsis: a model of pneumonia and the cecal ligation and puncture (CLP) polymicrobial model of infection. These data identify CD89 as a first-line innate receptor for bacterial clearance before adaptive responses can be mounted. Fc receptors may emerge as a class of innate receptors for various bacteria with pleiotropic roles.

The Expression of the Ubiquitin Ligase SIAH2 (Seven In Absentia Homolog 2) Is Increased in Human Lung Cancer.

OBJECTIVES: Lung cancer is the leading cause of cancer-related deaths worldwide. Overall 5-year survival has shown little improvement over the last decades. Seven in absentia homolog (SIAH) proteins are E3 ubiquitin ligases that mediate proteasomal protein degradation by poly-ubiquitination. Even though SIAH proteins play a key role in several biological processes, their role in human cancer remains controversial. The aim of the study was to document SIAH2 expression pattern at different levels (mRNA, protein level and immunohistochemistry) in human non-small cell lung cancer (NSCLC) samples compared to surrounding healthy tissue from the same patient, and to analyse the association with clinicopathological features. MATERIALS AND METHODS: One hundred and fifty-two samples from a patient cohort treated surgically for primary lung cancer were obtained for the study. Genic and protein expression levels of SIAH2 were analysed and compared with clinic-pathologic variables. RESULTS: The present study is the first to analyze the SIAH2 expression pattern at different levels (RNA, protein expression and immunohistochemistry) in non-small cell lung cancer (NSCLC). We found that SIAH2 protein expression is significantly enhanced in human lung adenocarcinoma (ADC) and squamous cell lung cancer (SCC). Paradoxically, non-significant changes at RNA level were found, suggesting a post-traductional regulatory mechanism. More importantly, an increased correlation between SIAH2 expression and tumor grade was detected, suggesting that this protein could be used as a prognostic biomarker to predict lung cancer progression. Likewise, SIAH2 protein expression showed a strong positive correlation with fluorodeoxyglucose (2-deoxy-2(18F)fluoro-D-glucose) uptake in primary NSCLC, which may assist clinicians in stratifying patients at increased overall risk of poor survival. Additionally, we described an inverse correlation between the expression of SIAH2 and the levels of one of its substrates, the serine/threonine kinase DYRK2. CONCLUSIONS: Our results provide insight into the potential use of SIAH2 as a novel target for lung cancer treatment.

AM404 inhibits NFAT and NF-κB signaling pathways and impairs migration and invasiveness of neuroblastoma cells.

N-Arachidonoylphenolamine (AM404), a paracetamol lipid metabolite, is a modulator of the endocannabinoid system endowed with pleiotropic activities. AM404 is a dual agonist of the Transient Receptor Potential Vanilloid type 1 (TRPV1) and the Cannabinoid Receptor type 1 (CB1) and inhibits anandamide (AEA) transport and degradation. In addition, it has been shown that AM404 also exerts biological activities through TRPV1- and CB1 -independent pathways. In the present study we have investigated the effect of AM404 in the NFAT and NF-κB signaling pathways in SK-N-SH neuroblastoma cells. AM404 inhibited NFAT transcriptional activity through a CB1- and TRPV1-independent mechanism. Moreover, AM404 inhibited both the expression of COX-2 at transcriptional and post-transcriptional levels and the synthesis of PGE2. AM404 also inhibited NF-κB activation induced by PMA/Ionomycin in SK-N-SH cells by targeting IKKß phosphorylation and activation. We found that Cot/Tlp-2 induced NFAT and COX-2 transcriptional activities were inhibited by AM404. NFAT inhibition paralleled with the ability of AM404 to inhibit MMP-1, -3 and -7 expression, cell migration and invasion in a cell-type specific dependent manner. Taken together, these data reveal that paracetamol, the precursor of AM404, can be explored not only as an antipyretic and painkiller drug but also as a co-adjuvant therapy in inflammatory and cancer diseases.

The fungal metabolite galiellalactone interferes with the nuclear import of NF-κB and inhibits HIV-1 replication.

Galiellalactone (GL) is a metabolite produced by the fungus Galiella rufa that presents antitumor and immunomodulatory activities. GL interferes with the binding to DNA of signal transducer and activator of transcription (STAT)-3 and also inhibits other signal pathways such as NF-κB, but the mechanism of action in this pathway remains unknown. In this study we report that GL inhibits vesicular stomatitis virus-recombinant HIV-1 infection and the NF-κB-dependent transcriptional activity of the HIV-LTR promoter. We found that GL prevents the binding of NF-κB to DNA but neither affects the phosphorylation and degradation of NF-κB inhibitory protein, IκBα, nor the phosphorylation and acetylation of the NF-κB p65 subunit. However, GL prevents the association of p65 with the importin α3 impairing the nuclear translocation of this transcription factor. Using a biotinylated probe we found that GL binds to p65 but not to importin α3. Therefore, GL is a dual NF-κB/STAT3 inhibitor that could serve as a lead compound for the development of novel drugs against HIV-1, cancer and inflammatory diseases.