Expression of monoacylglycerol lipase as a marker of tumour invasion and progression in malignant melanoma.

BACKGROUND: Accumulating evidence suggests that the lipid lytic enzyme monoacylglycerol lipase (MAGL) promotes tumour invasion and metastasis through up-regulation of pro-tumorigenic signalling lipids in several tumour cell lines. However, the expression status of MAGL in clinical melanoma tissues and its clinicopathological significance remain unclear. OBJECTIVE: To correlate the tumour expression status of MAGL with the clinicopathological information of patients with malignant melanoma. METHODS: Polymerase chain reaction (PCR) array screening was performed, and the results were validated using immunocytochemical analysis of tumour and non-tumour melanocytic cell lines. Immunohistochemical staining for MAGL was performed for 74 melanoma samples, including 48 primary and 26 metastatic tumours, in which the expression of MAGL was determined by evaluating the percentage of MAGL-positive tumour cells and the MAGL staining intensity. Finally, we analysed the association of MAGL expression status with tumour progression, tumour thickness and vascular invasion of the primary lesion. RESULTS: Immunocytochemical analysis revealed that MAGL was expressed in all 12 melanoma cell lines, but not in normal human epidermal melanocytes. In the immunohistochemical analysis, positive staining for MAGL was noted in 32 of 48 (64.5%) primary lesions, 14 of 17 (82.4%) lymph node metastatic lesions and 7 of 9 (77.8%) skin metastatic lesions. Metastatic tumours had a significantly higher staining intensity (P = 0.033 for lymph node, P = 0.010 for skin). In the analysis of primary lesions, higher MAGL expression correlated with greater tumour thickness (P = 0.015) and the presence of vascular invasion (P = 0.017). On further evaluation of MAGL-positive primary lesions, staining intensity of MAGL tended to be higher in deeper areas of the tumour mass. CONCLUSIONS: The expression of MAGL in tumour cells reflects the aggressiveness of melanoma cells and may serve as a marker of tumour progression.

Prdm5 suppresses Apc(Min)-driven intestinal adenomas and regulates monoacylglycerol lipase expression.

PRDM proteins are tissue-specific transcription factors often deregulated in diseases, particularly in cancer where different members have been found to act as oncogenes or tumor suppressors. PRDM5 is a poorly characterized member of the PRDM family for which several studies have reported a high frequency of promoter hypermethylation in cancer types of gastrointestinal origin. We report here the characterization of Prdm5 knockout mice in the context of intestinal carcinogenesis. We demonstrate that loss of Prdm5 increases the number of adenomas throughout the murine small intestine on an Apc(Min) background. By using the genome-wide ChIP-seq (chromatin immunoprecipitation (ChIP) followed by DNA sequencing) and transcriptome analyses we identify loci encoding proteins involved in metabolic processes as prominent PRDM5 targets and characterize monoacylglycerol lipase (Mgll) as a direct PRDM5 target in human colon cancer cells and in Prdm5 mutant mouse intestines. Moreover, we report the downregulation of PRDM5 protein expression in human colon neoplastic lesions. In summary, our data provide the first causal link between Prdm5 loss and intestinal carcinogenesis, and uncover an extensive and novel PRDM5 target repertoire likely facilitating the tumor-suppressive functions of PRDM5.

Las lipasas: enzimas con potencial para el desarrollo de biocatalizadores inmovilizados por adsorción interfacial: [revisión] / Lipases: enzymes having the potential for developing immobilised biocatalysts by interfacial adsorption: [review]

Las lipasas son enzimas con propiedades funcionales muy interesantes que permiten su utilización práctica en diversos campos de las industrias agroquímica, farmacéutica, de detergentes y alimentaria, así como en química fina. Entre las aplicaciones más importantes de estas moléculas se encuentran: la resolución de mezclas racémicas, la obtención de compuestos ópticamente puros y la bioconversión de principios activos. En este trabajo se presenta una amplia revisión del tema, que abarca desde aspectos estructurales y funcionales de las lipasas, hasta la inmovilización de estas enzimas mediante adsorción interfacial y su empleo en biotecnología.

Lipases are enzymes with very interesting functional properties that allow their practical use in different fields of Agro-Chemical, Pharmaceutical and Food industries, as well as in Fine Chemistry. Among the most relevant applications of these molecules are: racemic mixtures resolution, obtainment of optically pure compounds and bioconversion of active principles. In this work a broad review of this topic is presented. This includes since structural and functional features of lipases until the immobilization of these enzymes by interfacial adsorption and their employment in biotechnology.

Gold(III) porphyrin 1a inhibited nasopharyngeal carcinoma metastasis in vivo and inhibited cell migration and invasion in vitro.

A physiologically stable gold compound, gold(III) meso-tetraphenylporphyrin (gold-1a), has been shown to be effective in inducing apoptosis and prolonging the survival of hepatocellular carcinoma (HCC)-bearing rats as well as inhibiting the tumor growth of mice bearing nasopharyngeal carcinoma (NPC), neuroblastoma and colon carcinoma. In this study, we showed that gold-1a prolonged the survival of NPC metastasis-bearing mice and inhibited intrahepatic and lung metastasis. Histologically, gold-1a markedly reduced tumor microvessel formation. Consistently, in in vitro studies, gold-1a inhibited migration and invasion of C666-1 human NPC cells. The data strongly support the use of gold(III) compounds to treat cancer metastasis.

BDNF regulates neuronal sensitivity to endocannabinoids.

The diacylglycerol lipases (DAGLalpha/beta) synthesize 2-arachidonylglycerol (2-AG), the major endocannabinoid in the developing and adult brain (eCB). This lipid acts on cannabinoid receptors to regulate axonal growth and guidance, activity-dependent synaptic plasticity and adult neurogenesis, and can also protect neurons from excitotoxicity. 2-AG action is generally terminated by monoacylglycerol lipase (MAGL), however we know very little about the mechanisms that regulate neuronal sensitivity to eCBs. In the present study we show that the brain-derived neurotrophic factor (BDNF) can determine neuronal sensitivity to eCBs. In this context, in cultured cerebellar granule neurons (CGNs) BDNF increases the expression of CB1 receptor transcripts and decreases expression of MAGL transcripts. Using phosphorylation of Akt as the readout, we show that BDNF can promote a stable increase in neuronal sensitivity to eCBs. For example, concentrations of 2-AG and noladin either (NE) that normally do not lead to Akt phosphorylation in control neurons do so in neurons pre-treated with BDNF. In addition, Akt phosphorylation in response to a wide range of concentrations of NE was always greater in neurons pre-treated with BDNF. Our data suggests the existence of a positive feedback loop that might sustain neuronal survival in the normal brain.

Gene expression profiling of peripheral blood in patients with abdominal aortic aneurysm.

OBJECT: Abdominal aortic aneurysm (AAA) pathogenesis remains poorly understood. This study investigated the gene expression profile of peripheral blood from patients with AAA using microarray technology. METHODS AND RESULTS: We determined gene expression profiles in pooled RNA from 10 AAA patients and 10 matched controls with arrays representing 14,000 transcripts. Microarray data for selected genes were confirmed by real-time PCR in two different AAA (n=36) and control (n=36) populations and integrated with biochemical data. We identified 91 genes which were differentially expressed in AAA patients. Gene Ontology analysis indicated a significant alteration of oxygen transport (increased hemoglobin gene expression) and lipid metabolism [including monoglyceride lipase and low density lipoprotein receptor-related protein 5 (LRP5) gene]. LRP5 expression was associated inversely with serum lipoprotein(a) [Lp(a)] concentration. CONCLUSIONS: Increased expression of hemoglobin chain genes as well as of genes involved in erythrocyte mechanical stability were observed in the AAA RNA pools. The association between low levels of LRP5 gene expression and increased levels of Lp(a) in AAA patients suggests a potential role of LRP5 in Lp(a) catabolism. Our data underline the power of microarrays in identifying further molecular perturbations associated with AAA.

The cannabinoid CB1 receptor is expressed in pancreatic delta-cells.

Antagonists of cannabinoid CB1 receptor (CB1, CNR1) promote weight loss and decrease hyperglycemia in patients with type 2 diabetes. While the endocannabinoid system may modulate islet hormone secretion, the cell-type expressing CB1 receptor in islets has not been fully resolved. In this study, we verified receptor gene expression in rodent islets and cell lines and examined the distribution of CB1 receptor in mouse, rat, and human islets by confocal immunofluorescence (IF) microscopy. IF demonstrated CB1 receptor was present in beta-cell lines, but co-localized solely with somatostatin in the islet delta-cells of Zucker rats, C57BL/6 mice, and humans; no CB1 receptor expression was observed in alpha-, beta-, or pp-cells. Similarly, a rat somatostatinoma cell line, MSL-G2-Tu6, was found to express CB1 receptor. We also found monoacylglycerol lipase (MAGL) to be expressed in delta-cells and fatty acid amide hydrolase (FAAH) to be expressed in alpha-cells. The specific expression of CB1 in delta-cells suggests that the ECS may play a role in modulating islet hormone secretion. As there are some differences between our findings and previous reports, further studies, including detailed physiological studies of the effects of the ECS on islet function, are warranted.