Interleukin-1 gene polymorphisms and gastric cancer risk in a high-risk Italian population

OBJECTIVES

Host genetic factors, including the IL1 gene cluster, play a key role in determining the long-term outcome of Helicobacter pylori infection. The aim of the study was to investigate the relationship between selected IL1 loci polymorphisms and gastric cancer risk in an Italian population.

METHODS

In a case-control study we compared the IL1B-31 and IL1B+3954 biallelic and IL1RN pentaallelic variable number of tandem repeats (VNTR) polymorphisms in 185 gastric cancer patients and 546 controls randomly sampled from the general population of an area at high gastric cancer risk (Tuscany, Central Italy).

RESULTS

Genotype frequencies of the IL1B-31 T/C, IL1B+3954 C/T, and IL1RN polymorphisms among our population controls were in Hardy-Weinberg equilibrium. In multivariate analyses, no increase in gastric cancer risk was observed for the IL1B-31*C- and IL1B+3954*T- carriers; a significant 50% increase emerged for IL1RN*2 allele carriers (OR = 1.49; 95% CI: 1.01-2.21). Analyses based on combined genotypes showed also that the association with IL1RN*2 allele was limited to two-variant allele carriers who were also homozygous for the IL1B-31*T allele (OR = 2.23; 95% CI: 1.18-4.23) with a statistically significant interaction between these two genotypes (p= 0.043). Haplotype analysis showed an increased risk for the haplotype IL1RN*2/IL1B-31*T.

CONCLUSIONS

Our results suggest that host genetic factors (such as the IL1RN and the IL1B-31 polymorphisms) interact in the complex process of gastric carcinogenesis in this high-risk Italian population. Overall, this effect appears more modest than previously reported in other populations, supporting the hypothesis that other still-to-be-defined factors are important in gastric carcinogenesis. These findings might be due to a haplotype effect.

Psychoactive substance consumption in eating disorders

Research investigating the comorbidity between eating disorders and substance-use disorders have reported positive but contrasting results. The aim of this study was to further explore this association by studying patterns of consumption of the entire range of psychoactive substances (alcohol, specific drugs, prescribed psychotropics) in a large sample (N=271) of eating-disorder DSM-IV subtypes. Results show that subjects suffering from anorexia of the restrictive type show significantly less drug-consumption behaviors and alcohol abuse and/or dependence disorders than purging anorexic and bulimic subjects. No difference was found in the total consumption of psychotropics among the four groups of eating disorders. However, more than half of eating-disorder subjects are regular consumers of psychotropics. Among these regular consumers, bulimics self-prescribe and increase their doses of psychotropics significantly more than anorexics. Features of impulsivity that are associated with purging and bulimic behaviors could play a specific role in these patterns of comorbidity and account for such differences.

Phorbol ester-induced disruption of the CD4-Lck complex occurs within a detergent-resistant microdomain of the plasma membrane. Involvement of the translocation of activated protein kinase C isoforms

Recent studies have highlighted the existence of discrete microdomains at the cell surface that are distinct from caveolae. The function of these microdomains remains unknown. However, recent evidence suggests that they may participate in a subset of transmembrane signaling events. In hematopoietic cells, these low density Triton-insoluble (LDTI) microdomains (also called caveolae-related domains) are dramatically enriched in signaling molecules, such as cell surface receptors (CD4 and CD55), Src family tyrosine kinases (Lyn, Lck, Hck, and Fyn), heterotrimeric G proteins, and gangliosides (GM1 and GM3). Human T lymphocytes have become a well established model system for studying the process of phorbol ester-induced down-regulation of CD4. Here, we present evidence that phorbol 12-myristate 13-acetate (PMA)-induced down-regulation of the cell surface pool of CD4 occurs within the LDTI microdomains of T cells. Localization of CD4 in LDTI microdomains was confirmed by immunoelectron microscopy. PMA-induced disruption of the CD4-Lck complex was rapid (within 5 min), and this disruption occurred within LDTI microdomains. Because PMA is an activator of protein kinase C (PKC), we next evaluated the possible roles of different PKC isoforms in this process. Our results indicate that PMA induced the rapid translocation of cytosolic PKCs to LDTI microdomains. We identified PKCalpha as the major isoform involved in this translocation event. Taken together, our results support the hypothesis that LDTI microdomains represent a functionally important plasma membrane compartment in T cells.