Association Between Nitrite and Nitrate Intake and Risk of Gastric Cancer: A Systematic Review and Meta-Analysis.

BACKGROUND Studies have shown inconsistent associations of nitrite and nitrate intake with the risk of gastric cancer or its associated mortality. We performed a meta-analysis of observational studies to evaluate the correlation of nitrite and nitrate intake with the risk of gastric cancer. MATERIAL AND METHODS We searched for studies reporting effect estimates and 95% confidence intervals (CIs) of gastric cancer in PubMed, EMBASE, and the Cochrane Library through November 2018. The summary results of the included studies were pooled using a random-effects model. RESULTS Eighteen case-control and 6 prospective cohort studies recruiting 800 321 participants were included in this study. The summary results indicated that the highest (odds ratio [OR], 1.27; 95%CI, 1.03-1.55; P=0.022) or moderate (OR: 1.12; 95%CI, 1.01-1.26; P=0.037) nitrite intake were associated with a higher risk of gastric cancer. However, we noted that high (OR, 0.81; 95%CI, 0.68-0.97; P=0.021) or moderate (OR, 0.86; 95%CI, 0.75-0.99; P=0.036) nitrate intakes were associated with a reduced risk of gastric cancer. These associations differed when stratified by publication year, study design, country, the percentage of male participants, assessment of exposure, adjusted model, and study quality. CONCLUSIONS High or moderate nitrite intake was associated with higher risk of gastric cancer, whereas high or moderate nitrate intake was correlated with lower risk of gastric cancer.

Differential DNA methylation profiles of human B lymphocytes and Epstein-Barr virus-immortalized B lymphocytes.

OBJECTIVE: This study aimed to comprehensively assess Epstein-Barr virus (EBV)-induced methylation alterations of B cell across whole genome. METHODS: We compared DNA methylation patterns of primary B cells and corresponding lymphoblastoid cell lines (LCLs) from eight participants. The genome-wide DNA methylation profiles were compared at over 850,000 genome-wide methylation sites. RESULTS: DNA methylation analysis revealed 87,732 differentially methylated CpG sites, representing approximately 12.41% of all sites in LCLs compared to primary B cells. The hypermethylated and hypomethylated CpG sites were about 22.75% or 77.25%, respectively. Only 0.8% of hypomethylated sites and 4.5% of hypermethylated sites were located in CpG islands, whereas 8.0% of hypomethylated sites and 16.3% of hypermethylated sites were located in shore (N_shore and S_shore). Using principal component analysis of the DNA methylation profiles, primary B cells and LCLs could be accurately predicted. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differently methylated genes revealed that most of the top GO biological processes were related to cell activation and immune response, and some top enrichment pathways were related with activation and malignant transformation of human B cells. CONCLUSIONS: Our study demonstrated genome-wide DNA methylation variations between primary B cells and corresponding LCLs, which might yield new insight on the methylation mechanism of EBV-induced immortalization.

Polymorphic distribution and forensic effectiveness study of eight miniSTR in Chinese Uyghur ethnic group.

We obtained the allelic frequencies and forensic efficiency data for eight mini short tandem repeat loci including Penta E, D12S391, D6S1043, D2S1338, D19S433, CSF1PO, Penta D and D19S253 loci from a sample of 128 unrelated Uyghur individuals from China. The amplification products of the eight STR loci are <240 bp in size. A total of 94 alleles were observed and the corresponding allelic frequencies ranged from 0.0039 to 0.3438 in the present study. Observed genotype distributions for each locus do not show deviations from Hardy-Weinberg equilibrium expectations. The combined power of discrimination, combined power of exclusion and combined matching probability of the eight STR loci equaled to 0.999999999963373, 0.9997770 and 3.6627 × 10(-11), respectively. Because of the small fragment length of PCR products and the high degree of polymorphisms, the eight STR loci are highly beneficial for the forensic analysis of degraded DNA samples which are commonly observed in forensic cases. The STR data of the Uyghur group were compared with the previously published population STR data of other groups from different ethnic or areas, and significant differences were observed among these groups at some loci.

miRNA-765 mediates multidrug resistance via targeting BATF2 in gastric cancer cells.

Elucidation of the mechanisms underlying multidrug resistance (MDR) is required to ensure the efficacy of chemotherapy against gastric cancer (GC). To investigate this issue, here we identified that microRNA-765 (miRNA-765) is up-regulated both in MDR GC cell lines and in specimens from patients who are not responding to chemotherapy. In addition, down-regulation of miRNA-765 increased the sensitivity of GC cells to anticancer drugs, whereas its overexpression had the opposite effect. Moreover, miRNA-765 suppressed drug-induced apoptosis and positively regulated the expression of MDR-related genes. Finally, we showed that the basic leucine zipper ATF-like transcription factor 2, a tumor suppressor gene, is the functional target of miRNA-765. In summary, these results suggest that miRNA-765 may promote MDR via basic leucine zipper ATF-like transcription factor 2 in GC cells.

Evaluating the Association of Eight Polymorphisms with Cancer Susceptibility in a Han Chinese Population.

BACKGROUND: The identification of susceptibility genes for specific types of cancer can provide necessary information for the complete characterization of cancer syndromes. Eight single nucleotide polymorphisms (SNPs), rs465498, rs17728461, rs4488809, rs753955, rs13361707, rs9841504, rs2274223, and rs13042395, were reported by genome wide association studies (GWASs) to be closely related to the susceptibility of lung cancer (LC), gastric cancer (GC) or esophageal cancer (EC) in Han population from northern or southern China. However, Chinese Han people from different geographic areas may have different genetic backgrounds. This study aims to assess the genetic associations of the eight SNPs mentioned above with three cancers risk in a Han population from northwest China. METHODS: A total of 186 cancer-free controls and 436 cases with non-small cell lung cancer (NSCLC) (159 cases), non-cardia GC (167 cases) or EC (110 cases) were enrolled in this study. Chi-square test and polytomous logistic regression analyses were used to estimate the association between eight cancer-related SNPs and three cancers in a Han Chinese population from northwest China. The logistic regression results were adjusted for confounding factors and Benjamini and Hochberg False Discovery Rate (FDR) method was used to adjust the multiple hypothesis tests. Association analyses by cigarette smoking or alcohol drinking status were analyzed by crossover analyses. RESULTS: One of the eight SNPs, rs17728461 was associated with NSCLC susceptibility (in a heterozygous model, OR = 0.44, 95% CI = 0.27-0.72, p = 0.001). Two SNPs, rs753955 and rs13042395, were associated with the risk of non-cardia GC in different genetic models (p < 0.05). No SNPs were associated with EC. The crossover analyses showed that the rs13042395 CT genotype, combined with cigarette smoking or alcohol drinking, could further increase the risk for non-cardia GC (p < 0.05). CONCLUSIONS: These results indicated that rs17728461 may be specifically associated with the risk of NSCLC. rs753955 and rs13042395 were specifically associated with susceptibility to non-cardia GC in Ningxia Han Chinese. Susceptibility-associated polymorphisms in the northwestern Han Chinese were not very consistent with those in the northern Han Chinese or southern Han Chinese. The validation of these findings with a functional evaluation and a larger population is still required.

miR-138 might reverse multidrug resistance of leukemia cells.

Here we firstly investigated the role of miR-138 in multidrug resistance of leukemia cells. miR-138 was found up-regulated in the vincristine-induced multidrug resistance (MDR) leukemia cell line HL-60/VCR as compared with HL-60 cells. Up-regulation of miR-138 could reverse resistance of both P-glycoprotein-related and P-glycoprotein-non-related drugs on HL-60/VCR cells, and promote adriamycin-induced apoptosis, accompanied by increased accumulation and decreased releasing amount of adriamycin. miR-138 could significantly down-regulate the expression of P-glycoprotein, Bcl-2, and the transcription of the multidrug resistance gene 1. Further study of the biological functions of miR-138 might be helpful for developing possible strategies to treat leukemia.