Donghui Cao

Decreased Galectin-9 and Increased Tim-3 Expression Are Related to Poor Prognosis in Gastric Cancer

Introduction Galectin-9 (Gal-9) induces adhesion and aggregation of certain cell types and inhibits the metastasis of tumor cells. T-cell immunoglobulin–and mucin domain-3–containing molecule 3 (TIM-3) plays a pivotal role in immune regulation. The aim of this study is to investigate Gal-9 and TIM-3 alterations in gastric cancer and their prognostic values. Methods Gal-9 and Tim-3 expression was evaluated using a tissue microarray immunohistochemistry method in 305 gastric cancers, of which 84 had paired adjacent normal samples. Cell lines SGC-7901, BGC-823, MGC-803, MKN45 and GES-1 were also stained. Correlations were analyzed between expression levels of Gal-9 and Tim-3 protein and tumor parameters or clinical outcomes. Results Gal-9 and Tim-3 stained positive on tumor cells in 86.2% (263/305), and 60.0% (183/305) patients with gastric cancer, respectively. Gal-9 expression was significantly higher in cancer than in normal mucosa (P<0.001). Reduced Gal-9 expression was associated with lymph-vascular invasion, lymph node metastasis, distant metastasis and worse TNM staging (P = 0.034, P = 0.009, P = 0.002 and P = 0.043, respectively). In contrast, Tim-3 expression was significantly lower in cancer than in control mucosa (P<0.001). Patients with lymph-vascular invasion had higher expression levels of Tim-3 (P<0.001). Moreover, multivariate analysis shows that both high Gal-9 expression and low Tim-3 expression were significantly associated with long overall survival (P = 0.002, P = 0.010, respectively); the combination of Gal-9 and Tim-3 expression was an independent prognostic predictor for patients with gastric cancer (RR: 0.43; 95%CI: 0.20–0.93). H.pylori infection status was not associated with Gal-9 and Tim-3 expression (P = 0.102, P = 0.565). Conclusion The results suggest that expression of Gal-9 and Tim-3 in tumor cells may be a potential, independent prognostic factor for patients with gastric cancer. Gal-9 and TIM-3 may play an important part in the gastric carcinogenesis.

DNA methyltransferase3a expression is an independent poor prognostic indicator in gastric cancer

AIM To explore the alteration of DNA methyltransferase expression in gastric cancer and to assess its prognostic value. METHODS From April 2000 to December 2010, 227 men and 73 women with gastric cancer were enrolled in the study. The expression of DNA methyltransferases (DNMTs), including DNMT1, DNMT3a and DNMT3b, in the 300 cases of gastric carcinoma, of which 85 had paired adjacent normal gastric mucus samples, was evaluated by immunohistochemistry using a tissue microarray. Serum anti-Helicobacter pylori (H. pylori) IgG was detected by enzyme-linked immunosorbent assay (ELISA). The relationships between the above results and the clinicopathological characteristics were analyzed. Their prognostic value was evaluated using the Cox proportional hazards model. RESULTS In gastric cancer, expression of DNMTs was mainly seen in the nucleus. Weak staining was also observed in the cytoplasm. Expression of DNMT1, DNMT3a and DNMT3b in gastric cancer was significantly higher compared to that in the paired control samples (60.0% vs 37.6%, 61.2% vs 4.7%, and 94.1% vs 71.8%, P < 0.01). The overall survival rate was significantly higher in the DNMT3a negative group than in the DNMT3a positive group in gastric cancer patients (Log-rank test, P = 0.032). No significant correlation was observed between DNMT1 and DNMT3b expression and the overall survival time (Log-rank test, P = 0.289, P = 0.347). Multivariate regression analysis indicated that DNMT3a expression (P = 0.025) and TNM stage (P < 0.001), but not DNMT1 (P = 0.54) or DNMT3b (P = 0.62), were independent prognostic factors in gastric cancer. H. pylori infection did not induce protein expression of DNMTs. CONCLUSION The results suggest that expression of DNMT3a is an independent poor prognostic indicator in gastric cancer. DNMT3a might play an important role in gastric carcinogenesis.

Serum pepsinogen II is a better diagnostic marker in gastric cancer

AIM To investigate screening makers for gastric cancer, we assessed the association between gastric cancer and serum pepsinogens (PGs). METHODS The subjects comprised 450 patients with gastric cancer, 111 individuals with gastric atrophy, and 961 healthy controls. Serum anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG), PGI and PG II were detected by enzyme-linked immunosorbent assay. Gastric atrophy and gastric cancer were diagnosed by endoscopy and histopathological examinations. Odds ratios and 95%CIs were calculated using multivariate logistic regression. RESULTS Rates of H. pylori infection remained high in Northeastern China. Rates of H. pylori IgG positivity were greater in the gastric cancer and gastric atrophy groups compared to the control group (69.1% and 75.7% vs 49.7%, P < 0.001). Higher levels of PG II (15.9 μg/L and 13.9 μg/L vs 11.5 μg/L, P < 0.001) and lower PGI/PG II ratio (5.4 and 4.6 vs 8.4, P < 0.001) were found in patients with gastric cancer or gastric atrophy compared to healthy controls, whereas no correlation was found between the plasma PGI concentration and risk of gastric cancer (P = 0.537). In addition, multivariate logistic analysis indicated that H. pylori infection and atrophic gastritis were independent risk factors for gastric cancer. Lower plasma PGI/PG II ratio was associated with higher risks of atrophy and gastric cancer. Furthermore, plasma PG II level significantly correlated with H. pylori-infected gastric cancer. CONCLUSION Serum PG II concentration and PGI/PG II ratio are potential biomarkers for H. pylori-infected gastric disease. PG II is independently associated with risk of gastric cancer.

Polymorphisms of the DNA Methyltransferase 1 Associated with Reduced Risks of Helicobacter pylori Infection and Increased Risks of Gastric Atrophy

Introduction DNA methyltransferase-1(DNMT1) is an important enzyme in determining genomic methylation patterns in mammalian cells. We investigated the associations between SNPs in the DNMT1 gene and risks of developing H. pylori seropositivity, gastric atrophy and gastric cancer in the Chinese population. Methods The study consisted of 447 patients with gastric cancer; 111 patients with gastric atrophy; and 961 healthy controls. Five SNPs, rs10420321, rs16999593, rs8101866, rs8111085 and rs2288349 of the DNMT1 gene were genotyped. Anti-H.pylori IgG was detected by ELISA. Gastric atrophy was screened by the level of serum pepsinogen Ιand II and then confirmed by endoscopy and histopatholgical examinations. Results The age- and sex-adjusted OR of H. pylori seropositivity was 0.67 (95%CI: 0.51–0.87) for rs8111085 TC/CC genotypes, significantly lower than the TT genotype in healthy controls. The adjusted OR of H.pylori seropositivity was 0.68 (95%CI: 0.52–0.89) for rs10420321 AG/GG genotypes. In addition, patients carrying rs2228349 AA genotype have a significantly increased risk for H.pylori seropositivity (OR = 1.67; 95%CI: 1.02–2.75). Further haplotype analyses also showed that the ATTTG and ATCTA are significantly associated with increased risks in H.pylori infection compared to the GTCCG haplotype (OR = 1.38, 95%CI: 1.08–1.77; OR = 1.40, 95% CI: 1.09–1.80). The adjusted ORs of gastric atrophy were 1.66 (95%CI: 1.06–2.61) for rs10420321 GG genotype, and 1.67 (95%CI 1.06–2.63, P = 0.03) for rs8111085 CC genotype, but no association was found between SNPs in the DNMT1 gene and risk of developing gastric cancer. Conclusions Individuals with rs10420321 GG and rs8111085 CC genotype of the DNMT1 gene were associated with reduced risks for H.pylori infection. On the other hand, higher risks of gastric atrophy were found in the carriers with these two genotypes compared to other genotypes. Our results suggested that SNPs of DNMT1 could be used as genotypic markers for predicting genetic susceptibilities to H.pylori infection and risks in gastric atrophy.

Canolol Inhibits Gastric Tumors Initiation and Progression through COX-2/PGE2 Pathway in K19-C2mE Transgenic Mice

4-vinyl-2, 6-dimethoxyphenol (canolol) is an antioxidant phenolic compound extracted from crude canola oil. In current research, K19-C2mE transgenic mice, developing hyperplastic tumors spontaneously in the glandular stomach, were used to study the mechanisms involved in the anti-inflammation and anti-tumor effects of canolol. Tg mice receiving canolol diet had a reduced tumor incidence, to 41.2%, compared with Non-treatment Tg mice, 77.8% of which had gastric tumor (P=0.002). Besides that, the mean tumor diameter was decreased from 6.5mm to 4.5mm (P<0.001) after canolol administration. COX-2/PGE2 pathway is known to play pivotal role in inflammation-induced gastric tumorigenesis. The neutrophils and lymphocytes infiltration was suppressed significantly, and the mRNA levels of the proinflammatory cytokines COX-2, IL-1β and IL-12b were also downregulated in gastric mucosa. Additionally, immunohistochemical analysis showed that COX-2, EP2, Gαs and β-catenin, key factors involving in PGE2 signal transduction, were positive staining with higher H scores in Non-treatment Tg mice, while the expressions were suppressed significantly by 0.1% canolol (P<0.001). In addition, tumor-suppressor miR-7 was reactivated after canolol administration, and COX-2 was showed to be a functional target of miR-7 to suppress the tumor progression. In conclusion, canolol could inhibit the gastritis-related tumor initiation and progression, and the suppression effect was correlated with the blocking up of canonical COX-2/PGE2 signaling pathway and might be regulated by miR-7.

DNMT3a rs1550117 polymorphism association with increased risk of Helicobacter pylori infection.

BACKGROUND DNA methyltransferase-3a (DNMT3a) plays significant roles in embryogenesis and the generation of aberrant methylation in carcinogenesis. This study aimed to investigate associations between single nucleotide polymorphisms (SNPs) of the DNMT3a gene and risk of Helicobacter pylori infection, gastric atrophy and gastric cancer. METHODS The subjects comprised 447 patients with gastric cancer; 111 individuals with gastric atrophy and 961 healthy controls. Two SNPs (rs1550117 and rs13420827) of the DNMT3a gene were genotyped by Taqman assay. DNMT3a expression was analyzed in cancer tissues from 89 patients by tissue microarray technique. Odds ratio (ORs) and 95% confidence intervals were calculated by multivariate logistic regression. RESULTS Among healthy controls, risk of H.pylori infection was significantly higher in subjects with the rs1550117 AA genotype, compared to those with GG/AG genotypes of DNMT3a [OR=2.08, (95%CI: 1.02-4.32)]. However, no significant correlation was found between the two SNPs and risk of developing gastric atrophy or gastric cancer. In addition, no increase in DNMT3a expression was observed in the gastric cancer with H.pylori infection. CONCLUSIONS This study revealed that DNMT3a rs1550117 polymorphism is significantly associated with an increased risk of H. pylori infection, but did not support any evidence for contributions of DNMT3a rs1550117 and rs13420827 to either gastric atrophy or gastric cancer. The biological roles of DNMT3a polymorphisms require further investigation.

Increased expression of tyrosine phosphatase SHP-2 in Helicobacter pylori-infected gastric cancer

AIM To explore the alteration of tyrosine phosphatase SHP-2 protein expression in gastric cancer and to assess its prognostic values. METHODS Three hundred and five consecutive cases of gastric cancer were enrolled into this study. SHP-2 expression was carried out in 305 gastric cancer specimens, of which 83 were paired adjacent normal gastric mucus samples, using a tissue microarray immunohistochemical method. Correlations were analyzed between expression levels of SHP-2 protein and tumor parameters or clinical outcomes. Serum anti-Helicobacter pylori (H. pylori) immunoglobulin G was detected with enzyme-linked immunosorbent assay. Cox proportional hazards model was used to evaluate prognostic values by compassion of the expression levels of SHP-2 and disease-specific survivals in patients. RESULTS SHP-2 staining was found diffuse mainly in the cytoplasm and the weak staining was also observed in the nucleus in gastric mucosa cells. Thirty-two point five percent of normal epithelial specimen and 62.6% of gastric cancer specimen were identified to stain with SHP-2 antibody positively (P < 0.001). Though SHP-2 staining intensities were stronger in the H. pylori (+) group than in the H. pylori (-) group, no statistically significant difference was found in the expression levels of SHP-2 between H. pylori (+) and H. pylori (-) gastric cancer (P = 0.40). The SHP-2 expression in gastric cancer was not significantly associated with cancer stages, lymph node metastases, and distant metastasis of the tumors (P = 0.34, P = 0.17, P = 0.52). Multivariate analysis demonstrated no correlation between SHP-2 expression and disease-free survival (P = 0.86). CONCLUSION Increased expression of SHP-2 protein in gastric cancer specimen suggesting the aberrant up-regulation of SHP-2 protein might play an important role in the gastric carcinogenesis.

CD44 but not CD24 expression is related to poor prognosis in non-cardia adenocarcinoma of the stomach

BackgroundRecent studies have focused on the diagnostic and prognostic significance of CD24 and CD44 expression in human cancers. This study aimed to explore changes in CD44 and CD24 expression levels in patients with gastric cancer and to assess their prognostic values.MethodsCD44 and CD24 expression levels were investigated immunohistochemically in tumor samples from 290 patients with non-cardia gastric adenocarcinoma, of whom 77 had paired adjacent normal gastric mucosa. CD24 and CD44 mRNA levels were determined by quantitative polymerase chain reaction in 34 patients. Serum anti-Helicobacter pylori IgG was detected by enzyme-linked immunosorbent assay. Relationships between CD44 and CD24 protein expression levels and tumor parameters were analyzed and their prognostic values were evaluated by Cox proportional hazards models.ResultsCD24 and CD44 expression levels were significantly higher in patients with gastric cancer compared with those in paired controls (45.5% vs. 0.0%, and 61.0% vs. 0.0%, P < 0.001). Among 290 patients, the overall survival rate was significantly higher in CD44(−) compared with CD44(+) patients (log-rank test, P = 0.035). However, there was no significant correlation between CD24 expression and overall survival time (log-rank test, P = 0.115). Multivariate regression analysis indicated that positive CD44 expression (P = 0.029), TNM staging (P < 0.001), and lymphovascular invasion (P = 0.016), but not CD24 expression (P = 0.065), were independent prognostic factors in gastric cancer.ConclusionsIndividual expression of CD44 was associated with poor survival in patients with gastric carcinoma.

Polymorphism of DNA Methyltransferase 3b and Association with Development and Prognosis in Gastric Cancer

Objective DNA methyltransferase 3b (DNMT3b) plays an important role in abnormal methylation during tumorigenesis. Polymorphism of the DNMT3b gene may influence DNMT3b activity and be associated with cancer risk. This study aimed to investigate the association between single nucleotide polymorphisms (SNPs) of the DNMT3b gene and susceptibility and prognosis of gastric cancer. Methods Four hundred and forty-seven histologically-confirmed gastric cancer cases, 111 gastric atrophy cases and 961 tumor-free controls were enrolled into the study. Five tag SNPs (rs6119954, rs1569686, rs4911107, rs4911259 and rs8118663) of the DNMT3b gene were genotyped by TaqMan assay. DNMT3b expression was evaluated in 104 cancer tissues by immunohistochemistry method. Results The median follow-up time for 422 gastric patients with prognosis information was 55.1 (51.8–58.5) month. We found that individuals with the rs1569686 variant genotype (TG/GG) were significantly associated with poor prognosis in gastric cancer compared to those carrying the TT genotype (HR = 1.43, 95%CI: 1.02–1.99). This trend was more evident in the long-term survival of gastric cancer. Similar results were observed for the G allele carriers of rs4911107 and T allele carriers of rs4911259 as these two sites were in complete linkage disequilibrium with rs1569686. The rs8118663 GG carriers tended to live shorter than AA/AG genotype (HR = 2.72, 95%CI: 1.45–5.12) in patients living longer than 2.0 years. None of the five SNPs was associated with the risks of gastric cancer or gastric atrophy. And no relationship was found between each of the five SNPs and DNMT3b expression. Conclusions This study provides evidence that DNMT3b polymorphisms may predict long-term survival of gastric cancer. However, further studies are needed to reveal the underlying biological roles of DNMT3b polymorphism.

18β-glycyrrhetinic acid suppresses gastric cancer by activation of miR-149-3p-Wnt-1 signaling.

18β-glycyrrhetinic acid (GRA) exerts anti-tumor effects on various types of cancer. In the present study, we found that GRA attenuated the severity of gastritis and suppressed gastric tumorigenesis in transgenic mice. We also discovered that miR-149-3p was downregulated in gastric cancer tissues and cell lines as compared to normal gastric tissues and epithelial cells, but was upregulated by GRA. miR-149-3p expression also correlated negatively with lymphnode metastasis. Our functional assays showed that miR-149-3p overexpression inhibited cell proliferation and cell cycle progression while inducing apoptosis, while inhibition of miR-149-3p had the opposite effects. In addition, we identified Wnt-1 as a direct target of miR-149-3p. These data suggest that GRA inhibits the initiation and progression of gastric tumors by ameliorating the inflammatory microenvironment through downregulation of COX-2 expression and by inhibiting Wnt-1 expression through the upregulation of tumor suppressor miR-149-3p. GRA may thus have the potential to serve as a useful therapeutic agent for the prevention and treatment of gastric cancer.