The GAS6/ProS-TAM system is composed of two vitamin K-dependent ligands (GAS6 and protein S) and their three protein tyrosine kinase receptors TYRO3, AXL and MERTK, known as the TAM receptors. The system plays a prominent role in conditions of injury, inflammation and repair. In murine models of atherosclerotic plaque formation, mutations in its components affect atherosclerosis severity. Here we used Taqman low-density arrays and immunoblotting to study mRNA and protein expression of GAS6, ProS and the TAM receptors in human carotid arteries with different degrees of atherosclerosis. The results show a clear down-regulation of the expression of AXL in atheroma plaques with respect to normal carotids that is matched by decreased abundance of AXL in protein extracts detected by immunoblotting. A similar decrease was observed in PROS1 mRNA expression in atherosclerotic carotids compared to the normal ones, but in this case protein S (ProS) was clearly increased in protein extracts of carotid arteries with increasing grade of atherosclerosis, suggesting that ProS is carried into the plaque. MERTK was also increased in atherosclerotic carotid arteries with respect to the normal ones, suggesting that the ProS-MERTK axis is functional in advanced human atherosclerotic plaques. MERTK was expressed in macrophages, frequently in association with ProS, while ProS was abundant also in the necrotic core. Our data suggest that the ProS-MERTK ligand-receptor pair was active in advanced stages of atherosclerosis, while AXL signalling is probably down-regulated.

MicroRNAs (miRNAs) are post-transcriptional gene regulators involved in a wide range of biological processes including tumorigenesis. Deregulation of miRNA pathways has been associated with cancer but the contribution of their genetic variability to this disorder is poorly known. We analyzed the genetic association of gastric cancer (GC) and its anatomical and histological subtypes, with 133 single-nucleotide polymorphisms (SNPs) tagging 15 isolated miRNAs and 24 miRNA clusters potentially involved in cancer, in 365 GC cases and 1,284 matched controls within the European Prospective Investigation into Cancer and Nutrition cohort. Various SNPs were associated with GC under the log-additive model. Furthermore, several of these miRNAs passed the gene-based permutation test when analyzed according to GC subtypes: three tagSNPs of the miR-29a/miR-29b-1 cluster were associated with diffuse subtype (minimum p-value=1.7 × 10-4; odds ratio, OR=1.72; 95% confidence interval, CI=1.30-2.28), two tagSNPs of the miR-25/miR-93/miR-106b cluster were associated with cardia GC (minimum p-value=5.38 × 10-3; OR=0.56, 95% CI=0.37-0.86) and one tagSNP of the miR-363/miR-92a-2/miR-19b-2/ miR-20b/miR-18b/miR-106a cluster was associated with noncardia GC (minimum p-value=5.40 × 10-3; OR=1.41, 95% CI=1.12-1.78). Some functionally validated target genes of these miRNAs are implicated in cancer-related processes such as methylation (DNMT3A, DNMT3B), cell cycle (E2F1, CDKN1A, CDKN1C), apoptosis (BCL2L11, MCL1), angiogenesis (VEGFA) and progression (PIK3R1, MYCN). Furthermore, we identified genetic interactions between variants tagging these miRNAs and variants in their validated target genes. Deregulation of the expression of these miRNAs in GC also supports our findings, altogether suggesting for the fist time that genetic variation in MIR29, MIR25, MIR93 and MIR106b may have a critical role in genetic susceptibility to GC and could contribute to the molecular mechanisms of gastric carcinogenesis. What's New? Even though deregulation of miRNA expression has been associated with human cancers, the contribution of miRNAs to cancer genetic susceptibility is unclear. Here the authors designed a panel of 133 SNPs tagging 104 candidate miRNA genes and analysed their association with gastric cancer (GC). They describe an unreported significant genetic association of GC with miRNA clusters in chromosomes 7 and X including miR-29, miR-25, miR-93, and miR-106. These miRNAs have been previously involved in the pathophysiology of GC and have functionally validated target genes implicated in cancer-related processes. The data suggest these miRNAs as novel genetic susceptibility factors for GC

SummaryCarotid atherosclerosis (CA) is one of the most common causes of stroke, and recent studies suggest that pathways initiated by the interaction of the plasma vitamin K-dependent protein GAS6 with the tyrosine kinase receptors TYRO3, AXL and MERTK (TAM) may have a relevant role in atherogenesis. Furthermore, our previous studies indicated an association between GAS6 and stroke. The aim of this study was to analyse the genetic association between SNPs and haplotypes in GAS6-TAM genes and CA. We performed a case-control study with 233 CA patients confirmed by nuclear magnetic resonance angiography and 202 patients who suffered from cardioembolic (non atherogenic) stroke. For all included subjects information on established risk factors was available. Genotyping of 16 selected tagSNPs was performed by real-time PCR, using either FRET or TaqMan probes. Adjusted logistic regression (LR) analyses indicated that rs2289743 in TYRO3 and rs869016 in MERTK were associated to CA, decreasing its risk (OR [95%CI]=0.39 [0.16–0.94] and OR [95%CI]=0.31 [0.14–0.69], respectively). Linkage disequilibrium results were consistent with the haplotype blocks described in HapMap and adjusted LR analyses revealed that the haplotype ACAA in MERTK, containing the minor allele of the associated SNP, was also associated to CA. No association was observed with GAS6 and AXL variants, which suggests that CA is not the mechanism underlying the reported association between GAS6 and stroke. The association between TYRO3 and MERTK variants and carotid atherosclerosis found in this study reinforces a physiological role of the GAS6-TAM pathway in atherogenesis.

Metabolizing enzymes, which often display genetic polymorphisms, are involved in the activation of compounds present in tobacco smoke that may be relevant to gastric carcinogenesis. We report the results of a study looking at the association between risk of gastric adenocarcinoma and polymorphisms in genes CYP1A1, CYP1A2, EPHX1, and GSTT1. A nested case-control study was carried out within the European Prospective Investigation into Cancer and Nutrition, developed in 10 European countries. The study includes 243 newly diagnosed cases of histologically confirmed gastric adenocarcinoma and 946 controls matched by center, age, sex, and date of blood collection. Genotypes were determined in nuclear DNA from WBCs. We found an increased risk of gastric cancer for homozygotes for C (histidine) variant in Y113H of EPHX1 (odds ratio, 1.91; 95% confidence interval, 1.19-3.07) compared with subjects with TC/TT. There was also a significant increased risk for smokers carrying at least one variant allele A in Ex7+129C>A (m4) of CYP1A1 and never smokers with null GSTT1 and allele A in the locus À3859G>A of CYP1A2. Most of these genes are involved in the activation and detoxification of polycyclic aromatic hydrocarbons, suggesting a potential role of these compounds in gastric carcinogenesis. (Cancer Epidemiol Biomarkers Prev