Ming-Tsan Lin

Interleukin-10 genotypes associate with the risk of gastric carcinoma in Taiwanese Chinese.

The association of cytokine genotypes with gastric carcinoma (GC) may be influenced by environmental factors and varies among different populations. Few studies have addressed the impact of different cytokine genotypes on the development and progression of GC. We analyzed 11 functional polymorphisms in tumor necrosis factor‐α (TNF‐α), interleukin (IL)‐1, IL‐4 and IL‐10 genes in 220 Taiwanese Chinese with GC and in 230 healthy controls. The risk of genotypes was adjusted with confounding environmental risks. Our results revealed that the frequency of Helicobacter pylori infection [odds ratio (OR) 1.7, 95% confidence interval (CI) 1.19–2.56], cigarette smoking (OR 2.02, 95% CI 1.38–2.95) and high IL‐10 producer genotype (OR 2.67, 95% CI 1.29–5.50) was significantly increased in the entire GC patients. Among different subtypes of GC, a higher risk of developing diffuse type (OR 1.64, 95% CI 1.01–2.67) or cardia cancer (OR 2.44, 95% CI 1.13–2.67) was observed for the CT/CC genotype of IL‐4 at the position −590, whereas the high IL‐10 producer genotype was significantly linked with the risk of cardia cancer (OR 3.21, 95% CI 1.06–9.73) or advanced stage (OR 2.29, 95% CI 1.12–4.64). No association was noted between GC and controls in the distribution of IL‐1 and TNF‐α genotypes. Logistic regression analyses revealed that H. pylori infection (OR 1.7, 95% CI 1.14–2.52), cigarette smoking (OR 1.87, 95% CI 1.27–‐2.96) and IL‐10 genotype (OR 2.54, 95% CI 1.24–5.61) are independent risks for GC. Independent effects of IL‐10 genotype, H. pylori infection and cigarette smoking indicate that carcinogenesis of GC is influenced by a variety of host and environmental factors.

Randomized clinical trial of single-incision laparoscopic cholecystectomy versus minilaparoscopic cholecystectomy.

Transumbilical single‐incision laparoscopic cholecystectomy (SILC) and minilaparoscopic cholecystectomy (MLC) are both increasingly being used to treat symptomatic gallstones. The present study compared SILC and MLC with respect to outcome in a prospective randomized trial.

The involvement of PI 3-K/Akt-dependent up-regulation of Mcl-1 in the prevention of apoptosis of Hep3B cells by interleukin-6.

Interleukin-6 (IL-6) is a pleitrophic cytokine that not only regulates growth and differentiation of many cell types, but also induces production of acute phase proteins (AAP) in hepatocytes. Our previous works have demonstrated that both PI 3-K/Akt and STAT3 pathways were concomitantly activated and cooperatively mediated the anti-apoptotic effect of IL-6. This investigation reports that IL-6 protected cells against apoptosis induced by a variety of agents including, TGF-β, UV and retinoic acid (RA) in Hep3B cells, suggesting that IL-6 is a fundamental determinant of hepatic cell survival. Mcl-1, but not other Bcl-2 family members, was rapidly up-regulated by IL-6, with a peak (approximately 3–4-fold) appearing at 4 h. Transient transfection of cells with a mcl-1 antisense vector, resulting in a 50–60% reduction of the anti-apoptotic effect of IL-6, indicating that Mcl-1 is a downstream effector of IL-6. Which signaling pathway transduced by IL-6 responsible for the Mcl-1 up-regulation was further investigated. In Hep3B cells, the JAK/STAT3, ERK, and PI 3-K/Akt pathways were activated by IL-6 stimulation. Blocking JAK/STAT3 activation with a dominant-negative mutant STAT3F or a JAK inhibitor AG490 could not influence IL-6-mediated Mcl-1 up-regulation. Similarly, PD98059 treatment, a MEK specific inhibitor, also failed to inhibit Mcl-1 expression. However, the IL-6-induced Mcl-1 up-regulation was effectively attenuated in the presence of PI 3-K inhibitors, LY294002 and wortmannin. Expression of dominant-negative Akt, but not Etk, could abrogate the IL-6-induced increase of Mcl-1. In conclusion, our results suggest that the anti-apoptotic effect of IL-6 is mediated, at least in part, by Mcl-1 expression and that is mainly through the PI 3-K/ Akt-dependent pathway.

Interleukin-6 Increases Vascular Endothelial Growth Factor and Angiogenesis in Gastric Carcinoma

Interleukin-6 (IL-6) is a proinflammatory cytokine associated with the disease status of gastric carcinoma (GC). Vascular endothelial growth factor (VEGF) is a potent tumor angiogenic factor in GC. In this study, we attempted to clarify whether IL-6 can regulate VEGF and angiogenesis in GC. GC samples from 54 surgical specimens were subjected to immunohistochemical examination of IL-6, VEGF, and tumor microvessels, and results showed that IL-6 was positively correlated with VEGF expression and tumor vasculature. We determined VEGF expression in four GC cell lines by ELISA, revealing that GC cells can produce significant amount of VEGF with increasing dose and duration of IL-6 stimulation. Next, a luciferase reporter gene assay was employed to determine the signaling pathway driving the VEGF promoter by IL-6, which showed that the JAK/STAT pathway is involved in the stimulation of VEGF gene expression. The effects of IL-6 on angiogenesis in vitro and in vivo were evaluated by HUVEC studies and the Matrigel plug assay, respectively. Results showed that IL-6 effectively promoted HUVEC proliferation and tube formation in vitro and Matrigel plug vascularization in vivo, primarily by inducing VEGF in GC. This study provides evidence that the multifunctional cytokine, IL-6, may induce VEGF expression which increases angiogenesis in gastric carcinogenesis.

Tumor Necrosis Factor–α and Interleukin-10 Promoter Polymorphisms in Epstein-Barr Virus–Associated Gastric Carcinoma

To investigate whether genetic differences in cytokine promoter polymorphisms effect various outcomes after exposure to Epstein-Barr virus (EBV) infection, 30 patients with EBV-positive gastric carcinoma (GC), 120 patients with EBV-negative GC, and 220 control subjects were enrolled. Promoter polymorphisms of tumor necrosis factor (TNF)-alpha at positions -238 and -308 and of interleukin (IL)-10 at position -1082 were determined. The frequency of the high-producer allele (-308A) in the TNF-alpha gene was significantly higher among EBV-positive GC patients compared with control subjects (23.3% vs. 12.0%, P<.05), whereas the frequency of the high-producer allele (-1082G) in the IL-10 gene was significantly higher among EBV-negative GC patients compared with control subjects (6.3% vs. 3.0%, P<.05). These data support the notion that genetic factors may modify the outcomes of infectious diseases through different TNF-alpha- or IL-10-producing capabilities.

Epstein–Barr virus—associated gastric carcinomas: Relation to H. pylori infection and genetic alterations

BACKGROUND & AIMS The association of Epstein-Barr virus (EBV) and gastric carcinomas (GCs) has been shown to vary among different populations and certain histological subtypes. Few studies have addressed the status of Helicobacter pylori infection and genetic alterations in these EBV-positive or -negative GCs. METHODS Eleven gastric lymphoepithelioma-like carcinomas (LELCs) and 139 cases of common non-LELCs were evaluated for the presence of EBV DNA using polymerase chain reaction (PCR) and RNA in situ hybridization. H. pylori infection was determined by anti-H. pylori immunoglobulin G in preoperative sera. Immunostaining for p53, c-erbB-2, and E-cadherin was performed. Microsatellite instability was analyzed by PCR using 10 primers. RESULTS EBV was detected in 11 (100%) LELCs and in 19 (13.7%) of 139 common GCs. Compared with EBV-negative GCs, gastric LELCs tended to have a relatively higher frequency of proximal location, diffuse histological subtype, p53 overexpression, and reduced E-cadherin expression but a lower frequency of lymph node metastasis, previous H. pylori infection, and c-erbB-2 overexpression. In contrast, no significant difference of clinicopathologic and genetic profiles was observed between EBV-positive non-LELC GCs and EBV-negative GCs. No correlation of microsatellite instability was found among these 3 subsets of GCs. CONCLUSIONS Dissecting clinicopathologic characteristics and infection status of EBV and H. pylori provide additional evidence of etiological and genetic heterogeneity for GC. Distinct clinicopathologic and genetic pathways exist in gastric LELCs, in which EBV may play a more important role than H. pylori infection.

IL-6 induces AGS gastric cancer cell invasion via activation of the c-Src/RhoA/ROCK signaling pathway

Interleukin‐6 (IL‐6) is a multifunctional cytokine that is associated with the disease status and outcomes of gastric cancer. Nonetheless, the underlying mechanism of how IL‐6 promotes the spread of gastric cancer is still unclear. In this study, we used a modified Boyden chamber assay to test the invasion ability of different gastric cancer cell lines. Liposome‐mediated transfection was used to introduce an IL‐6 expression vector into AGS cells, and the transfectants were further examined for the expression of active RhoA and phosphorylated Src using a pull‐down assay and coimmunoprecipitation/Western blot analysis. Furthermore, RhoA expression in gastric adenocarcinoma specimens was investigated immunohistochemically. We documented that IL‐6 could promote AGS cell motility and invasiveness, and inhibition of RhoA expression by dominant negative RhoA, C3 transferase, or dominant negative Src expressing plasmids could effectively decrease the invasiveness of IL‐6 transfectants. We also documented an interaction between active RhoA and phosphorylated‐Src following IL‐6 treatment. Gastric cancers displaying high expression of RhoA are highly correlated with aggressive lymph node metastasis, more advanced tumor stage, histologically diffuse type and poorer survival. In conclusion, IL‐6 induces AGS gastric cancer cell invasion via activation of the c‐Src/RhoA/ROCK signaling pathway and RhoA expression could be used as a prognostic factor in patients with gastric adenocarcinoma.

miR-107 promotes tumor progression by targeting the let-7 microRNA in mice and humans

MicroRNAs (miRNAs) influence many biological processes, including cancer. They do so by posttranscriptionally repressing target mRNAs to which they have sequence complementarity. Although it has been postulated that miRNAs can regulate other miRNAs, this has never been shown experimentally to our knowledge. Here, we demonstrate that miR-107 negatively regulates the tumor suppressor miRNA let-7 via a direct interaction. miR-107 was found to be highly expressed in malignant tissue from patients with advanced breast cancer, and its expression was inversely correlated with let-7 expression in tumors and in cancer cell lines. Ectopic expression of miR-107 in human cancer cell lines led to destabilization of mature let-7, increased expression of let-7 targets, and increased malignant phenotypes. In contrast, depletion of endogenous miR-107 dramatically increased the stability of mature let-7 and led to downregulation of let-7 targets. Accordingly, miR-107 expression increased the tumorigenic and metastatic potential of a human breast cancer cell line in mice via inhibition of let-7 and upregulation of let-7 targets. By mutating individual sites within miR-107 and let-7, we found that miR-107 directly interacts with let-7 and that the internal loop of the let-7/miR-107 duplex is critical for repression of let-7 expression. Altogether, we have identified an oncogenic role for miR-107 and provide evidence of a transregulational interaction among miRNAs in human cancer development.

Association of the -160 C --> a promoter polymorphism of E-cadherin gene with gastric carcinoma risk.

A −160 C → A polymorphism in the promoter region of E‐cadherin has been shown to decrease gene transcription. This allelic variation might be a potential genetic marker for identifying individuals at risk for cancer. There remains no report regarding the polymorphism of E‐cadherin in gastric carcinoma (GC).

Genetic polymorphisms of cytochrome P450 2E1, glutathione S-transferase M1 and T1, and susceptibility to gastric carcinoma in Taiwan

Background and aims: Cytochrome P450 (CYP) and glutathione S-transferase (GST) enzymes are involved in activation and detoxification of many potential carcinogens. Genetic polymorphisms in these enzymes have been found to influence interindividual and interethnic susceptibility to cancer. Although CYP and GST enzymes are involved in the activation and detoxification of N-nitrosamines and related compound, studies on the relationship between genetic polymorphisms of CYP2E1, GSTT1, and GSTM1 and the risk of gastric carcinoma (GC) are few, and the results have been conflicting. Patients and methods: We conducted a hospital-based case-control study to investigate whether such variations affect the risk of developing GC. Subjects included 356 GC patients and 278 unaffected controls. Peripheral white blood cell DNA was obtained from all subjects. Genotyping of CYP2E1 was performed using a PCR-based restriction fragment length polymorphism assay. Deletion of GSTT1 and GSTM1 genes was assessed by multiplex PCR. Results: The distribution of c2/c2 genotype of CYP2E1, detected by PstI or RsaI digestion, differed significantly between GC patients and controls; the odds ratio was 2.9. It remained significant after adjustment with gender, histological subtypes (diffuse, intestinal, mixed), location (cardia, body, antrum/angle), and stage (early, advanced). In contrast, the prevalence of CYP2E1 DraI polymorphism and GSTT1 and GSTM1 null genotype was similar in controls and GC patients. Conclusion: Our findings suggest that the CYP2E1 genotype is a determinant of GC risk in Taiwan.