microRNA-146a inhibits G protein-coupled receptor-mediated activation of NF-κB by targeting CARD10 and COPS8 in gastric cancer

BACKGROUND: Gastric cancer is the second most common cause of cancer-related death in the world. Inflammatory signals originating from gastric cancer cells are important for recruiting inflammatory cells and regulation of metastasis of gastric cancer. Several microRNAs (miRNA) have been shown to be involved in development and progression of gastric cancer. miRNA-146a (miR-146a) is a modulator of inflammatory signals, but little is known about its importance in gastric cancer. We therefore wanted to identify targets of miR-146a in gastric cancer and examine its biological roles. RESULTS: The expression of miR-146a was evaluated by quantitative PCR (qPCR) and found up-regulated in the gastrin knockout mice, a mouse model of gastric cancer, and in 73% of investigated human gastric adenocarcinomas. Expression of miR-146a by gastric cancer cells was confirmed by in situ hybridization. Global analysis of changes in mRNA levels after miR-146a transfection identified two transcripts, caspase recruitment domain-containing protein 10 (CARD10) and COP9 signalosome complex subunit 8 (COPS8), as new miR-146a targets. qPCR, Western blotting and luciferase assays confirmed these transcripts as direct miR-146a targets. CARD10 and COPS8 were shown to be part of the G protein-coupled receptor (GPCR) pathway of nuclear factor-kappaB (NF-kappaB) activation. Lysophosphatidic acid (LPA) induces NF-kappaB activation via this pathway and over-expression of miR-146a inhibited LPA-induced NF-kappaB activation, reduced LPA-induced expression of tumor-promoting cytokines and growth factors and inhibited monocyte attraction. CONCLUSIONS: miR-146a expression is up-regulated in a majority of gastric cancers where it targets CARD10 and COPS8, inhibiting GPCR-mediated activation of NF-kappaB, thus reducing expression of NF-kappaB-regulated tumor-promoting cytokines and growth factors. By targeting components of several NF-kappaB-activating pathways, miR-146a is a key component in the regulation of NF-kappaB activity

(68)Ga-DOTATOC PET and gene expression profile in patients with neuroendocrine carcinomas:strong correlation between PET tracer uptake and gene expression of somatostatin receptor subtype 2

Somatostatin receptor expression on both protein and gene expression level was compared with in vivo (68)Ga-DOTATOC PET/CT in patients with neuroendocrine carcinomas (NEC). Twenty-one patients with verified NEC who underwent a (68)Ga-DOTATOC PET/CT between November 2012 and May 2014, were retrospectively included. By real-time polymerase chain reaction, we quantitatively determined the gene expression of several genes and compared with (68)Ga-DOTATOC PET uptake. By immunohistochemistry we qualitatively studied the expression of assorted proteins in NEC. The median age at diagnosis was 68 years (range 41-84) years. All patients had WHO performance status 0-1. Median Ki67 index was 50% (range 20-100%). Gene expression of somatostatin receptor subtype (SSTR) 2 and Ki67 were both positively correlated to the (68)Ga-DOTATOC uptake (r=0.89; p<0.0001 and r=0.5; p=0.021, respectively). Furthermore, SSTR2 and SSTR5 gene expression were strongly and positively correlated (r=0.57; p=0.006). This study as the first verifies a positive and close correlation of (68)Ga-DOTATOC uptake and gene expression of SSTR2 in NEC. SSTR2 gene expression has a stronger correlation to (68)Ga-DOTATOC uptake than SSTR5. In addition, the results indicate that the gene expression levels of SSTR2 and SSTR5 at large follow one another

miR-449 inhibits cell proliferation and is down-regulated in gastric cancer

<p>Abstract</p> <p>Background</p> <p>Gastric cancer is the fourth most common cancer in the world and the second most prevalent cause of cancer related death. The development of gastric cancer is mainly associated with <it>H. Pylori </it>infection leading to a focus in pathology studies on bacterial and environmental factors, and to a lesser extent on the mechanistic development of the tumour. MicroRNAs are small non-coding RNA molecules involved in post-transcriptional gene regulation. They are found to regulate genes involved in diverse biological functions and alterations in microRNA expression have been linked to the pathogenesis of many malignancies. The current study is focused on identifying microRNAs involved in gastric carcinogenesis and to explore their mechanistic relevance by characterizing their targets.</p> <p>Results</p> <p>Invitrogen NCode miRNA microarrays identified miR-449 to be decreased in 1-year-old <it>Gastrin </it>KO mice and in <it>H. Pylori </it>infected gastric tissues compared to tissues from wild type animals. Growth rate of gastric cell lines over-expressing miR-449 was inhibited by 60% compared to controls. FACS cell cycle analysis of miR-449 over-expressing cells showed a significant increase in the sub-G₁fraction indicative of apoptosis. ß-Gal assays indicated a senescent phenotype of gastric cell lines over-expressing miR-449. Affymetrix 133v2 arrays identified <it>GMNN</it>, <it>MET, CCNE2, SIRT1 </it>and <it>CDK6 </it>as miR-449 targets. Luciferase assays were used to confirm <it>GMNN</it>, <it>MET</it>, <it>CCNE2 </it>and <it>SIRT1 </it>as direct targets. We also show that miR-449 over-expression activated p53 and its downstream target p21 as well as the apoptosis markers cleaved CASP3 and PARP. Importantly, qPCR analyses showed a loss of miR-449 expression in human clinical gastric tumours compared to normal tissues.</p> <p>Conclusions</p> <p>In this study, we document a diminished expression of miR-449 in <it>Gastrin </it>KO mice and further confirmed its loss in human gastric tumours. We investigated the function of miR-449 by identifying its direct targets. Furthermore we show that miR-449 induces senescence and apoptosis by activating the p53 pathway.</p

The Apolipoprotein M/S1P Axis Controls Triglyceride Metabolism and Brown Fat Activity

Summary: Apolipoprotein M (apoM) is the carrier of sphingosine-1-phosphate (S1P) in plasma high-density lipoproteins. S1P is a bioactive lipid interacting with five receptors (S1P1–5). We show that lack of apoM in mice increases the amount of brown adipose tissue (BAT), accelerates the clearance of postprandial triglycerides, and protects against diet-induced obesity (i.e., a phenotype similar to that induced by cold exposure or β3-adrenergic stimulation). Moreover, the data suggest that the phenotype of apoM-deficient mice is S1P dependent and reflects diminished S1P1 stimulation. The results reveal a link between the apoM/S1P axis and energy metabolism. : Apolipoprotein M (apoM) is the carrier of sphingosine-1-phosphate (S1P) in lipoproteins. Christoffersen et al. show that lack of apoM in mice increases the amount of brown adipose tissue, accelerates the turnover of fat, and protects against obesity. The results reveal a link between the apoM/S1P axis and energy metabolism. Keywords: apolipoproteins, sphingolipids, sphingosine-1-phosphate, lipoproteins, lipid metabolism, triglyceride, brown adipose tissue, apo

Temozolomide as Second or Third Line Treatment of Patients with Neuroendocrine Carcinomas

Background. Knowledge of the clinical efficacy in recurrent neuroendocrine carcinomas is sparse. Treatment with temozolomide alone or in combination with capecitabine and bevacizumab has recently shown promising results. Patients and Methods. Analysis of consecutive patients with neuroendocrine carcinomas (Ki-67 proliferation index >20%) and performance status 0–2 treated with temozolomide 200 mg/sqm orally days 1–5 every 28 days after at least one previous platin-containing chemotherapy regimen. Results. Twenty-eight eligible patients received a median of 3 courses. Sixteen patients were evaluable for response: Six achieved stable disease and ten progressed. The median survival for the 28 patients was 3.5 months. Survival in patients with tumors of pancreatic origin (n=7) was 7.0 months versus 2.9 months in non-pancreatic origin (n=21). Patients in PS 0-1 (n=22) had a median survival of 4.5 months versus 1.1 months in patients in PS 2 (n=6). Ki-67 index ≥50% was associated with a significantly shorter median survival than Ki-67 index <50% (2.7 months versus 10.9 months). The treatment was well tolerated. Conclusion. Temozolomide monotherapy has limited effect in treatment of recurrent neuroendocrine carcinomas. Second line treatment with temozolomide in combination with other compounds should be further investigated in patients in good performance with Ki-67 index <50%