An integrated genomic approach identifies ARID1A as a candidate tumor-suppressor gene in breast cancer.

Tumor-suppressor genes (TSGs) have been classically defined as genes whose loss of function in tumor cells contributes to the formation and/or maintenance of the tumor phenotype. TSGs containing nonsense mutations may not be expressed because of nonsense-mediated RNA decay (NMD). We combined inhibition of the NMD process, which clears transcripts that contain nonsense mutations, with the application of high-density single-nucleotide polymorphism arrays analysis to discriminate allelic content in order to identify candidate TSGs in five breast cancer cell lines. We identified ARID1A as a target of NMD in the T47D breast cancer cell line, likely as a consequence of a mutation in exon-9, which introduces a premature stop codon at position Q944. ARID1A encodes a human homolog of yeast SWI1, which is an integral member of the hSWI/SNF complex, an ATP-dependent, chromatin-remodeling, multiple-subunit enzyme. Although we did not find any somatic mutations in 11 breast tumors, which show DNA copy-number loss at the 1p36 locus adjacent to ARID1A, we show that low ARID1A RNA or nuclear protein expression is associated with more aggressive breast cancer phenotypes, such as high tumor grade, in two independent cohorts of over 200 human breast cancer cases each. We also found that low ARID1A nuclear expression becomes more prevalent during the later stages of breast tumor progression. Finally, we found that ARID1A re-expression in the T47D cell line results in significant inhibition of colony formation in soft agar. These results suggest that ARID1A may be a candidate TSG in breast cancer.

Association between platelet endothelial cellular adhesion molecule 1 (PECAM-1/CD31) polymorphisms and acute myocardial infarction: a study in patients from Sicily.

Adhesion of circulating cells to the arterial surface is among the first detectable events in atherogenesis. Cellular adhesion molecules, expressed by the vascular endothelium and by circulating leucocytes, mediate cell recruitment and their transendothelial migration. Platelet endothelial cellular adhesion molecule 1 (PECAM-1/CD31), involved in this migration, has been associated with the developmental course of atherosclerosis. A few studies have investigated an association between coronary heart disease and single nucleotide polymorphisms (SNPs) located in functionally important domains of the PECAM-1/CD31 gene. In particular, Ser563Asn and Gly670Arg SNPs have been described as susceptibility factors involved in acute myocardial infarction (AMI) in the Japanese male population. To confirm these observations, we studied 96 male patients (mean age 40 years; age range 20-46) affected by AMI and 118 healthy male controls (mean age 38 years, age range: 20-55), and analysed for the following PECAM-1/CD31 SNPs: Val125Leu, Asn563Ser and Gly670Arg. The frequency of the Gly670Arg polymorphism was significantly higher in patients with AMI (58.9% vs. 48.3%; P = 0.019), whereas the frequencies of the other two SNPs (Leu125Val and Ser563Asn) were not significantly different between patients and controls. By comparing the observed number of 670Arg/Arg genotypes in the patients with the expected number, calculated from the allele frequency in a healthy population, a significance of P = 0.02 (odds ratio, 2.04; 95% CI: 1.1-3.7) was obtained, supporting a recessive model of inheritance. Hence, the differences between patients and controls are significant, but relatively small. However, as AMI is a multifactorial disease, any single mutation will only provide a small or modest contribution to the risk, which also depends on environmental interaction. All in all, we believe that the results of the present study would add support to the role of pro/anti-inflammatory genotypes in determining susceptibility or resistance to immune-inflammatory diseases, including atherosclerosis.

Gender-specific association between -1082 IL-10 promoter polymorphism and longevity.

Ageing is characterized by a pro-inflammatory status, which could contribute to the onset of major age-related diseases. Thus, genetic variations in pro- or anti-inflammatory cytokines might influence successful ageing and longevity. IL-10 is an appropriate candidate because it exerts powerful inhibitory effects on pro-inflammatory function. IL-10 production is controlled by several polymorphic elements in the 5' flanking region of IL-10 gene on 1q32 locus, involving alleles at two microsatellite regions and several polymorphisms in promoter region. We analysed in 190 Italian centenarians (>99 years old, 159 women and 31 men) and in 260 <60 years old control subjects (99 women and 161 men), matched for geographical distribution, genotype frequencies for -1082G-->A, -819C-->T and -592C-->A IL-10 proximal promoter gene biallelic polymorphisms by sequence specific probes. -1082G homozygous genotype was increased in centenarian men (P < 0.025) but not in centenarian women. No difference was found between centenarians and control subjects regarding the other two polymorphisms. The presence of -1082GG genotype, suggested to be associated with high IL-10 production, significantly increases the possibility to reach the extreme limit of human lifespan in men. Together with previous data on other polymorphic loci (Tyrosine Hydroxylase, mitochondrial DNA, IL-6, haemochromatosis, IFN-gamma), this finding points out that that gender is a major variable in the genetics of longevity, suggesting that men and women follow different strategies to reach longevity. Concerning the biological significance of this association, we have not searched for functional proves that IL-10 is involved. Thus, we should conclude that our data only suggest that a marker on 1q32 genomic region may be involved in successful ageing in man. However, recent data on IL-6 and IFN-gamma genes suggest that longevity is negatively associated with genotypes coding for a pro-inflammatory profile. Thus, it is intriguing that the possession of -1082G genotype, suggested to be associated with IL-10 high production, is significantly increased in centenarians.

A gender--dependent genetic predisposition to produce high levels of IL-6 is detrimental for longevity.

Current literature indicates that elevated IL-6 serum levels are associated with diseases, disability and mortality in the elderly. In this paper, we studied the IL-6 promoter genetic variability at -174 C/G locus and its effect on IL-6 serum levels in a total of 700 people from 60 to 110 years of age, including 323 centenarians. We found that the proportion of homozygotes for the G allele at -174 locus decreases in centenarian males, but not in centenarian females. Moreover, we found that, only among males, homozygotes for the G allele at -174 locus have higher IL-6 serum levels in comparison with carriers of the C allele. On the whole, our data suggest that those individuals who are genetically predisposed to produce high levels of IL-6 during aging, i.e. -174 locus GG homozygous men, are disadvantaged for longevity.

Increase of homozygosity in centenarians revealed by a new inter-Alu PCR technique.

In the present study a novel inter-Alu PCR technique that allows one to detect inter-individual differences in the genomic regions flanked by Alu repetitive sequences was developed. Two primers complementary to sequences present in different Alu repeats and marked with two different fluorochromes were used in the same PCR reaction, and the PCR products were separated and analyzed by capillary electrophoresis using an automatic sequencer. The method is highly reliable, and three patterns of peaks (QM376-400, QM780-790 and QM480) appeared to be representative for germ-line polymorphisms, as suggested by the results obtained in nine couples of monozygotic twins and four three-generation families. The frequency of these polymorphic peaks was studied in two different age groups (100 young subjects and 69 centenarians). In two out of the three regions (QM376-400 and QM480) a significant increase in homozygote genotypes frequency was observed in centenarians. These counterintuitive results suggest that increased homozygosity contributes to human longevity. This novel inter-Alu PCR approach could represent a valuable tool to identify longevity-associated DNA sequences interspersed throughout human genome, without making any a priori assumption about their nature and function.

Do men and women follow different trajectories to reach extreme longevity? Italian Multicenter Study on Centenarians (IMUSCE).

Gender accounts for important differences in the incidence and prevalence of a variety of age-related diseases. Considering people of far advanced age, demographic data document a clear-cut prevalence of females compared to males, suggesting that sex-specific mortality rates follow different trajectories during aging. In the present investigation, we report data from a nationwide study on Italian centenarians (a total of 1162 subjects), and from two studies on centenarians living in two distinct zones of Italy, i.e., the island of Sardinia (a total of 222 subjects) and the Mantova province (Northern Italy) (a total of 43 subjects). The female/male ratio was about 2:1 in Sardinia, 4:1 in the whole of Italy, and about 7:1 in the Mantova province. Thus, a complex interaction of environmental, historical and genetic factors, differently characterizing the various parts of Italy, likely plays an important role in determining the gender-specific probability of achieving longevity. Gender differences in the health status of centenarians are also reported, and an innovative score method to classify long-lived people in different health categories, according to clinical and functional parameters, is proposed. Our data indicate that not only is this selected group of people, as a whole, highly heterogeneous, but also that a marked gender difference exists, since male centenarians are less heterogeneous and more healthy than female centenarians. Immunological factors regarding the age-related increase in pro-inflammatory status, and the frequency of HLA ancestral haplotypes also show gender differences that likely contribute to the different strategies that men and women seem to follow to achieve longevity. Concerning the different impact of genetic factors on the probability of reaching the extreme limits of the human life-span, emerging evidence (regarding mtDNA haplogroups, Thyrosine Hydroxilase, and IL-6 genes) suggests that female longevity is less dependent on genetics than male longevity, and that female centenarians likely exploited a healthier life-style and more favorable environmental conditions, owing to gender-specific cultural and anthropological characteristics of the Italian society in the last 100 years.

[Body, muscle, and visceral nitrogen balance in catabolic patients. Modification with metabolic treatment]. / Bilancio azotato corporeo, muscolare e viscerale in pazienti catabolici. Modificazioni col trattamento metabolico.

In sixteen severely catabolic patients, two different nutritional treatments with the same nitrogen input (0.30 gN.kg-1.die-1) but with a different caloric support: 30 kcal.kg-1.die-1 foe group A and 15 kcal.kg-1.die-1 for group B were infused. Body nitrogen balance (BN), muscle nitrogen balance (BNm) and, calculated as a difference of the two, visceral nitrogen balance were measured in every patient on basal day and on the second day of total parenteral nutrition. Both nutritional treatment reduced the catabolic state in the same amount: this was confirmed by a less negative body BN and by the reduced excretion of 3-MEH and amino acidic catabolic markers. Otherwise in the other compartments the treatments showed different effects: the metabolic support was more reduced by treatment A than it was by B, supplying to visceral compartment a lower nitrogen amount: the nitrogen dismission from muscle compartment, available for visceral tissues, is greater with treatment B than with treatment A. In conclusion, even if both treatments show the same effect on body nitrogen balance, they penalize either one of the examined compartment or the other. To avoid this problem, the study and the use of tissue-specific nutrients are desiderable. Tissue-specific solutions may warrant the balance among body compartment without any further increase of the nitrogen rate.