Platelet-activating factor (PAF) receptor expression is associated with histopathological stage and grade and patients' survival in gastric adenocarcinoma.

Platelet activating factor (PAF) has been considered as potent inflammatory lipid mediator that exerts its actions by binding to PAF receptor (PAFR). PAF/PAFR system has been implicated in several pathophysiological states, including tumor progression, angiogenesis and metastasis. The present study aimed to evaluate the clinical significance of PAFR expression in gastric adenocarcinoma. PAFR protein expression was assessed immunohistochemically on 54 gastric adenocarcinoma tissue samples and was analyzed in relation with clinicopathological parameters, tumor proliferative capacity and patients' survival. PAFR was abundantly expressed in all gastric adenocarcinoma cases examined. Increased PAFR expression was significantly more frequently observed in well/moderately compared to poorly differentiated gastric adenocarcinoma cases (p=0.011). PAFR expression was significantly increased in intestinal- compared to diffuse-type cases (p=0.020). Elevated PAFR expression was significantly associated with smaller tumor size, absence of lymph node and organ metastasis and low tumor histopathological stage (p=0.025, p<0.001, p=0.009 and p<0.001, respectively). Additionally, patients presenting elevated PAFR expression had significantly longer survival times compared to those with low PAFR expression (log-rank test, p<0.001). These results support an important potential role of PAFR signalling in gastric malignant disease progression and render further research in this field a necessity.

RAS/PI3K crosstalk and cetuximab resistance in head and neck squamous cell carcinoma.

PURPOSE: Cetuximab, an antibody directed against the EGF receptor, is an effective clinical therapy for patients with head and neck squamous cell cancer (HNSCC). Despite great clinical promise, intrinsic or acquired cetuximab resistance hinders successful treatment outcomes but little is known about the underlying mechanism. EXPERIMENTAL DESIGN: To study the role of oncogenic HRAS in cetuximab resistance in HNSCC, the frequency of oncogenic HRAS mutations was determined in a cohort of 180 genomic DNAs from head and neck cancer specimens. We also used a combination of cetuximab-resistant cell lines and a transgenic mouse model of RAS-driven oral cancer to identify an oncogenic RAS-specific gene expression signature that promotes cetuximab resistance. RESULTS: Here, we show that activation of RAS signaling leads to persistent extracellular signal-regulated kinase 1/2 signaling and consequently to cetuximab resistance. HRAS depletion in cells containing oncogenic HRAS or PIK3CA restored cetuximab sensitivity. In our study, the gene expression signature of c-MYC, BCL-2, BCL-XL, and cyclin D1 upon activation of MAPK signaling was not altered by cetuximab treatment, suggesting that this signature may have a pivotal role in cetuximab resistance of RAS-activated HNSCC. Finally, a subset of patients with head and neck cancer with oncogenic HRAS mutations was found to exhibit de novo resistance to cetuximab-based therapy. CONCLUSIONS: Collectively, these findings identify a distinct cetuximab resistance mechanism. Oncogenic HRAS in HNSCC promotes activation of ERK signaling, which in turn mediates cetuximab resistance through a specific gene expression signature. Clin Cancer Res; 20(11); 2933-46. ©2014 AACR.

The anti-inflammatory effects of exercise training promote atherosclerotic plaque stabilization in apolipoprotein E knockout mice with diabetic atherosclerosis.

Physical exercise is the cornerstone of cardiovascular disease treatment. The present study investigated whether exercise training affects atherosclerotic plaque composition through the modification of inflammatory-related pathways in apolipoprotein E knockout (apoE(-/-)) mice with diabetic atherosclerosis. Forty-five male apoE(-/-) mice were randomized into three equivalent (n=15) groups: control (CO), sedentary (SED), and exercise (EX). Diabetes was induced by streptozotocin administration. High-fat diet was administered to all groups for 12 weeks. Afterwards, CO mice were euthanatized, while the sedentary and exercise groups continued high-fat diet for 6 additional weeks. Exercising mice followed an exercise program on motorized-treadmill (5 times/week, 60 min/session). Then, blood samples and atherosclerotic plaques in the aortic root were examined. A considerable (P<0.001) regression of the atherosclerotic lesions was observed in the exercise group (180.339 ± 75.613 x10(3)µm(2)) compared to the control (325.485 ± 72.302 x10(3)µm(2)) and sedentary (340.188 ± 159.108 x 10(3)µm(2)) groups. We found decreased macrophages, matrix metalloproteinase-2 (MMP-2), MMP-3, MMP-8 and interleukin-6 (IL-6) concentrations (P<0.05) in the atherosclerotic plaques of the exercise group. Compared to both control and sedentary groups, exercise training significantly increased collagen (P<0.05), elastin (P<0.001), and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) (P<0.001) content in the atherosclerotic plaques. Those effects paralleled with increased fibrous cap thickness and less internal elastic lamina ruptures after exercise training (P<0.05), while body-weight and lipid parameters did not significantly change. Plasma MMP-2 and MMP-3 concentrations in atherosclerotic tissues followed a similar trend. From our study we can conclude that exercise training reduces and stabilizes atherosclerotic lesions in apoE-/- mice with diabetic atherosclerosis. A favorable modification of the inflammatory regulators seems to explain those beneficial effects.

The role of ex-vivo gene therapy of vein grafts with Egr-1 decoy in the suppression of intimal hyperplasia.

OBJECTIVES: To test the hypothesis that vein graft intimal hyperplasia can be significantly suppressed by a single intra-operative transfection of the graft with a decoy oligonucleotide (ODN) binding the transcription factor Egr-1. DESIGN: Experimental study. MATERIALS AND METHODS: Jugular vein to carotid artery interposition grafts in rabbits were treated with Egr-1 decoy, mutant decoy ODN, vehicle alone, using a non-distending pressure of 300 mm Hg for 20 min, or were left untreated. All animals were fed a 2% cholesterol diet. The animals were sacrificed after 48h, 6 weeks and 12 weeks. Paraffin-embedded vein sections were subjected to angiometric analysis. RESULTS: Successful delivery of the ODN was confirmed by DAPI staining. Quantitative real-time PCR revealed a 60% decrease of the Egr-1 gene expression in the animals in which the Egr-1 decoy ODN was delivered. Cellular proliferation was also significantly decreased as indicated by the Ki-67 labelling index. An increase in intimal and medial thickness was found in all vein grafts. However, intimal thickness was significantly reduced in the grafts treated with Egr-1 decoy ODN, whereas luminal area was significantly increased. CONCLUSION: A single intra-operative pressure-mediated transfection of vein grafts with Egr-1 decoy ODN significantly suppresses intimal hyperplasia in a rabbit hypercholesterolaemic model.

Receptor-binding cancer antigen expressed on SiSo cells (RCAS1): a novel biomarker in the diagnosis and prognosis of human neoplasia.

The receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is a novel tumor-associated antigen that induces cell-cycle arrest and/or apoptosis in RCAS1 receptor-bearing human cells. Current evidence has revealed enhanced RCAS1 expression in the tumor malignant stage of several organs, which may play a crucial role in tumor progression by enabling cancer cells to evade immune surveillance. In the last few years, tissue RCAS1 protein expression and circulating levels in biofluids have further been the focus of extensive research as a diagnostic and prognostic marker in several human malignancies. The present article aimed to review the available data so far concerning the clinical significance of RCAS1 in human neoplasia. Reviewing of English literature revealed that tissue RCAS1 expression was associated with important clinicopathological parameters for patients' management and prognosis, being considered as an informative biomarker in several types of human malignancy. In addition, the current evidence supported a crucial role for RCAS1 in tumor immune escape, which renders this receptor a promising target for future (gene) therapeutic approaches. However, the clinical application of circulating RCAS1 concentrations in biofluids as a marker in the management and prognosis of tumor malignancies needs to be further explored, since the data so far are still extremely limited.