Expression of cyclooxygenase-2 in primary and remnant gastric carcinoma: comparing it with p53 accumulation,Helicobacter pylori infection,and vascular endothelial growth factor expression

BACKGROUND AND OBJECTIVES: Cyclooxygenase-2 (COX-2) expression may contribute to the synthesis of prostanoids, which have been related to carcinogenesis and tumor progression. It is well known that the gastric remnant is at greater risk of the development of gastric cancer than is the whole stomach; incidence rates for gastric cardia adenocarcinoma are rising in the United States and Europe. Our objective was to determine the involvement of COX-2 in primary and remnant gastric cancer tissues as well as in adjacent noncancerous mucosa. METHODS: We investigated the expression of COX-2 in 91 human gastric cancer tissue and adjacent noncancerous mucosa samples (40 remnant gastric cancer, 37 gastric cardia cancer, and 14 gastric corpus and antrum cancer), using immunohistochemistry. In addition, p53 expression, Helicobacter pylori infection, and vascular endothelial growth factor in the tissues were evaluated by immunohistochemical staining and compared with COX-2 expression. RESULTS: There were no significant differences in clinicopathological data in the gastric cancer tissues. There was a significant relation between the expression of COX-2 and p53 in gastric cancer tissues (P = 0.0048). However, vascular endothelial growth factor expression and Helicobacter pylori infection showed no correlation with the expression of COX-2. In the case of adjacent noncancerous mucosa, the positive rate of COX-2 expression was significantly higher in the remnant gastric cancers (75.0%) than in the primary gastric cancers (25.5%) (P < 0.0001). CONCLUSIONS: This information may help in the analysis of the carcinogenesis of gastric cancer; there is also a possibility that the COX-2 selective inhibitor to the remnant gastric cancer has a chemopreventive effect.     

Association of Helicobacter pylori Infection with Gastric Adenocarcinoma

Gastric adenocarcinoma is the most prevalent cancer in South Korea, and Helicobacter pylori (H. pylori) infection is also common. This study was performed to examine the association between H. pylori infection and gastric cancer, taking into account various other factors. To investigate the association between gastric adenocarcinoma and H. pylori infection, determined by urease-positive reaction in the CLO test, a total of 175 paired specimens (175 tumor and 175 tissues adjacent to tumor) of stomach cancer patients and a total of 113 control specimens were obtained. The positive H. pylori infection rates were 78.9% (138/175) among the patients in specimens of tumor or tissues adjacent to the tumor and 41.6% (47/113) among controls in the CLO test. A positive correlation between H. pylori infection and gastric cancer was observed (age-adjusted odds ratio, 7.0; MH χ²=34.5 with P <0.0005). These data suggest that stomach cancer patients in Korea have high infection rates of H. pylori regardless of site specificity, and this infection might be causally associated with stomach cancer.     

Molecular pathways: involvement of Helicobacter pylori-triggered inflammation in the formation of an epigenetic field defect, and its usefulness as cancer risk and exposure markers

Infection-associated cancers account for a large proportion of human cancers, and gastric cancer, the vast majority of which is associated with Helicobacter pylori infection, is a typical example of such cancers. Epigenetic alterations are known to occur frequently in gastric cancers, and H. pylori infection has now been shown to induce aberrant DNA methylation in gastric mucosae. Accumulation of aberrant methylation in gastric mucosae produces a field for cancerization, and methylation levels correlate with gastric cancer risk. H. pylori infection induces methylation of specific genes, and such specificity is determined by the epigenetic status in normal cells, including the presence of H3K27me3 and RNA polymerase II (active or stalled). Specific types of inflammation, such as that induced by H. pylori infection, are important for methylation induction, and infiltration of monocytes appears to be involved. The presence of an epigenetic field defect is not limited to gastric cancers and is observed in various types of cancers. It provides translational opportunities for cancer risk diagnosis incorporating life history, assessment of past exposure to carcinogenic factors, and cancer prevention.     

Gastric and intestinal phenotypes and histogenesis of advanced glandular stomach cancers in carcinogen-treated, Helicobacter pylori-infected Mongolian gerbils

The Helicobacter pylori-infected Mongolian gerbil (MG) has been established as an appropriate animal model for studies of stomach cancer development. However, there have hitherto been no data on the phenotypic classification of glandular stomach cancers in H. pylori-infected and non-infected MG. We therefore examined the phenotypes of 50 and six advanced glandular stomach cancers in H. pylori-infected and non-infected MG, respectively, as well as adjacent non-neoplastic mucosa, using several gastrointestinal epithelial phenotypic markers. The lesions were divided phenotypically into 21 gastric, 24 gastric-and-intestinal mixed, four intestinal and one null types, with 90.0% of the lesions harboring gastric elements and 56.0% demonstrating intestinal phenotypic expression in H. pylori-infected MG. All six lesions were classified as gastric type in non-infected MG. There was no clear correlation with the presence of intestinal metaplasia in surrounding mucosa. In conclusion, our data suggest that most advanced adenocarcinomas retain a gastric cellular phenotype in the glandular MG stomach. Thus, it might be proposed that intestinal metaplasia is a paracancerous phenomenon rather than a premalignant condition. H. pylori infection may trigger intestinalization of both stomach cancers and non-neoplastic mucosa.     

Diffuse submucosal cysts of the stomach associated with gastric cancer: contribution of Helicobacter pylori infections

Diffuse submucosal cysts (DSCs) in the stomach are often associated with gastric cancer and a high occurrence of multiple gastric cancers. We studied the clinicopathological features of four early gastric cancer patients with DSCs in the submucosal layer of the stomach. All patients had early gastric cancers with gastritis and erosion in the gastric mucosa, and were positive for Helicobacter pylori (H. pylori). Based on a review of the reported cases, we found that a very high proportion (>94%) of DSCs are associated with infection by H. pylori. Although DSCs have previously been considered to be paracancerous lesions of gastric cancer, we speculate that DSCs might be post-inflammatory changes following infection by H. pylori, which may result in the high incidence of gastric cancer development.     

Risk Factors and Epidemiology of Gastric Cancer in Pakistan

Gastric cancer is the 2nd most common cause of death among all cancers and is the 4th most common cancerin the world. The number of deaths due to gastric cancer is about 800,000 annually. Gastric cancer is morecommon in men as compared to women and is 3rd most common cancer after colorectal and breast cancers inwomen. A progressive rise in the incidence rate has been observed in females over the last 5 years. The highestincidence of stomach cancer is in China, South America and Eastern Europe. The incidence of gastric cancer has20 fold variation worldwide. Global variation is linked by two factors which play important role in developinggastric cancer. One is infection with Helicobacter pylori and the 2nd is diet. South Asia is a region with low risk,despite a high prevalence of H.pylori. Gastric carcinoma is common in southern region of India. Gastric canceris more readily treated if diagnosed early. This study aims to provide awareness about gastric cancer as well asan updated knowledge about risk factors and epidemiology of gastric cancer in Pakistan.     

Autocrine Signalling Through erbB Receptors Promotes Constitutive Activation of Protein Kinase B/Akt in Breast Cancer Cell Lines

The protein kinase PKB/Akt plays a pivotal role in promoting cell survival and proliferation. This study investigated the regulation of PKB/Akt activity in breast cancer cells. In primary invasive breast cancers PKB/Akt exhibited elevated phosphorylation at regulatory site Ser473 in 80% of cases, using immunohistochemistry. The degree of phospho-PKB/Akt immunoreactivity was positively correlated with the extent of its nuclear accumulation. Moderate/strong staining was seen in 31% of the samples but was absent in tumour-associated normal breast epithelia. To examine the mechanisms of PKB/Akt activation, we studied its phosphorylation in a panel of breast cancer cell lines. PKB/Akt was constitutively phosphorylated on both regulatory sites (Thr308 and Ser473) in the absence of serum growth factors in 7 of 8 lines but not in two cell lines derived from normal breast epithelia. Further analysis revealed that constitutive PKB/Akt phosphorylation was associated with loss of PTEN phosphatase expression (CAL51, MDA-MB-468, BT549 cells) and constitutive activation of erbB2 (SKBR3, BT474 cells). In two further breast cancer lines (T47D and HS578T) PKB/Akt phosphorylation was dependent upon autocrine factors acting primary through the epidermal growth factor receptor (EGFR) and erbB2. Conditioned medium from HS578T cells stimulated EGFR-dependent PKB/Akt phosphorylation in normal breast cells. These results demonstrate that PKB/Akt is frequently activated in breast cancer through diverse mechanisms, including autocrine signalling via erbB receptors.     

IFT80蛋白对肿瘤影响的研究

  目的  探讨IFT80（intraflagellar transport 80）蛋白在骨癌、肺癌、胰腺癌、胃癌、小肠癌、前列腺癌、乳腺癌和卵巢癌组织的表达分布情况与癌细胞增殖中的作用。  方法  免疫组织化学研究IFT80的表达,免疫荧光和细胞培养研究抑制IFT80后对癌细胞增殖的影响和纤毛之间的关系。  结果  1）IFT80在胃癌和肺癌组织中高表达,乳腺癌和小肠癌组织中中等表达,骨癌和卵巢癌组织中少量表达,前列腺癌和胰腺癌组织中几乎不表达;2）抑制IFT80后发现肺癌细胞增殖加快,纤毛减少变短;3）高分化,Ⅱ A期胃癌和正常胃组织中IFT80蛋白大量表达,而在低分化晚期,几乎不表达,在其他不同分化的胃癌中不同程度表达。  结论  在不同癌组织中IFT80分布情况不一致。IFT80分布在细胞纤毛上,通过其表达的减少来调节纤毛的数量和长短参与癌细胞的增殖,故在严重癌组织中含量最低。      

Preferential dependence of breast cancer cells versus normal cells on integrin-linked kinase for protein kinase B/Akt activation and cell survival

The emerging paradigm of "oncogene addiction" has been called an Achilles' heel of cancer that can be exploited therapeutically. Here, we show that integrin-linked kinase (ILK), which is either activated or overexpressed in many types of cancers, is a critical regulator of breast cancer cell survival through the protein kinase B (PKB)/Akt pathway but is largely dispensable for the survival of normal breast epithelial cells and mesenchymal cells. We show that inhibition of ILK activity with a pharmacologic ILK inhibitor, QLT-0267, results in the inhibition of PKB/Akt Ser473 phosphorylation, stimulation of apoptosis, and a decrease in mammalian target of rapamycin (mTOR) expression in human breast cancer cells. In contrast, QLT-0267 treatment has no effect on PKB/Akt Ser473 phosphorylation or apoptosis in normal human breast epithelial, mouse fibroblast, or vascular smooth muscle cells. The inhibition of PKB/Akt Ser473 phosphorylation by QLT-0267 in breast cancer cells was rescued by a kinase-active ILK mutant but not by a kinase-dead ILK mutant. Furthermore, a dominant-negative ILK mutant increased apoptosis in the MDA-MB-231 breast cancer cell line but not in normal human breast epithelial cells. The inhibitor was active against ILK isolated from all cell types but did not have any effect on cell attachment and spreading. Our data point to an "ILK addiction" of breast cancer cells whereby they become dependent on ILK for cell survival through the mTOR-PKB/Akt signaling pathway and show that ILK is a promising target for the treatment of breast cancer.     

Helicobacter pylori infection on the risk of stomach cancer and chronic atrophic gastritis.

Helicobacter pylori infection is associated with gastric adenocarcinoma. However, the mechanisms of this interaction are still unclear. This study was conducted to explore the effects of H. pylori infection on early and late stage gastric carcinogenesis. This study included 134 patients with adenocarcinoma of the stomach (ACS), 67 patients with chronic atrophic gastritis (CAG), and 65 normal controls recruited at Memorial Sloan-Kettering Cancer Center (MSKCC) from November 1, 1992 to November 1, 1994. Epidemiologic data were collected by a modified National Cancer Institute Health Habits History Questionnaire. H. pylori infection was diagnosed by pathological evaluation. Risk factors were analyzed using logistic regression. The odds ratio (OR) associated with H. pylori infection was 10.4 [95% confidence interval (CI): 2.6-41.6] for CAG and 11.2 (95% CI: 2.5-50.3) for gastric cancer in comparison with normal controls, with adjustment for pack-years of smoking, alcohol drinking, body mass index, total caloric intake, dietary fat and fiber intake, and Barrett's esophagus. But H. pylori infection was not associated with risk of stomach cancer when patients with stomach cancer were compared with patients with CAG (OR = 0.6, 95% CI: 0.3-1.3) after controlling for potential confounding variables. This association was persistent when only patients with both gastric cancer and chronic gastritis were considered as cases and patients with CAG were considered as controls (OR = 0.7, 95% CI: 0.3-2.0) in the multivariate analysis. Our results suggest that H. pylori infection may be involved in the early stage of development of CAG, but not in the development of stomach cancer from CAG, and indicate that strategies for prevention of stomach cancer should target the early stage to eliminate H. pylori infection in high-risk populations.     

Cripto: a novel target for antibody-based cancer immunotherapy

Cripto, a member of the epidermal growth factor-Cripto-FRL-Criptic (EGF-CFC) family, has been described recently as a potential target for immunotherapy (Adkins et al., J Clin Invest 2003;112:575-87). We have produced rat monoclonal antibodies (mAbs) to a Cripto 17-mer peptide, corresponding to the "EGF-like" motif of Cripto. The mAbs react with most cancers of the breast, colon, lung, stomach, and pancreas but do not react or react weakly with normal tissues. The mAbs inhibit cancer cell growth in vitro, and this effect was greater with cytotoxic drugs such as 5-fluorouracil, epirubicin, and cisplatin. The anti-Cripto mAbs prevent tumor development in vivo and inhibit the growth of established tumors of LS174T colon xenografts in Scid mice. The growth inhibitory effects with these mAbs may be greater than those described elsewhere, possibly because of IgM giving more effective cross-linking or binding to a different epitope (EGF-like region versus CFC region). The mechanism of inhibitory effects of the Cripto mAbs includes both cancer cell apoptosis, activation of c-Jun-NH(2)-terminal kinase and p38 kinase signaling pathways and blocking of Akt phosphorylation. Thus, Cripto is a unique target, and mAbs to Cripto could be of therapeutic value for human cancers.     

Expression and promoter methylation of the RASSF1A gene in sporadic breast cancers in Chinese women

The novel tumor suppressor RASSF1A is frequently inactivated during human tumorigenesis by promoter methylation. In this study, we detected the RASSF1A promoter methylation by methylated-specific PCR and investigated RASSF1A gene expression by semi-quantitative RT-PCR and immunohistochemical staining in 36 cases of breast cancer and their adjacent normal tissues in Chinese women. The promoter methylation of the RASSF1A gene was found to be a frequent event in the breast cancers (61.1%). RASSF1A methylation was not found in the matched adjacent normal tissues. The loss frequency of RASSF1A mRNA was 33.3% and that of the RASSF1A protein was 44.4% in breast cancers. RASSF1A mRNA and protein were all expressed in adjacent normal tissues. The mRNA and protein expression level of RASSF1A was significantly lower in breast cancer than in adjacent normal tissue. However, the promoter methylation of the RASSF1A gene in breast cancers were not correlated with clinical parameters, such as ages, histological types, TNM stages and lymph node metastases. Thus, the promoter methylation of RASSF1A was one reason for the low level of RASSF1A mRNA and protein expression and was a frequent event in primary sporadic breast tumorigenesis in Chinese women.     

The biology of Helicobacter pylori infection, a major risk factor for gastric adenocarcinoma.

Helicobacter pylori infection of the human stomach is the most important risk factor for development of gastric cancer. Whereas persistent viral infection leads to a number of cancers, H. pylori was the first bacteria linked to a human cancer. The exact mechanisms that lead to cancer induction are not clear, but study of the bacterial factors important for colonization and the host responses to the infection are starting to yield important clues.     

Sirt1 Gene Expression and Gastric Epithelial Cells Tumor Stage in Patients with Helicobacter pylori Infection

Introduction: The World Health Organization has categorized Helicobacter pylori as a carcinogen for gastriccancer, which causes human mortality worldwide. A number of studies have shown that H. pylori affects cell signalingin gastric epithelial cells and changes the expression of some proteins such as proinflammatory cytokines. Bacterialinfections may alter sirt1 and sirt2 genes expression in inflammatory tissues and cancer cells. In this study, sirt1 andsirt2 genes expression in gastric cancers was surveyed with reference to H. pylori status. Methods: Stomach biopsieswere collected from 50 gastric cancer patients, 25 H. pylori-positive and 25 H. pylori-negative as determined by theurea rapid test. Tumor grade was determined by a pathologist. After total RNA extraction from gastric cancer biopsysamples and cDNA synthesis, sirt1 and sirt2 genes expression levels were determined by Real Time PCR and ΔΔCTmethods. Results: There was no statistically significant link between H. pylori infection and sirt1 (P<0.899) and sirt2(P<0.169) genes expression in gastric epithelial cells. However, pathologic findings showed that there is a statisticallysignificant relationship between sirt1 gene expression and the tumor grade (P<0.024). Discussion: A statisticallysignificant association was found between sirt1 gene expression and tumor grade of gastric cancers that could be dueto effects on progression of cancer cells infected with H. pylori.     

Activation of the Akt/mammalian target of rapamycin/4E-BP1 pathway by ErbB2 overexpression predicts tumor progression in breast cancers.

The Akt/mammalian target of rapamycin (mTOR)/4E-BP1 pathway is considered to be a central regulator of protein synthesis, involving the regulation of cell proliferation, differentiation, and survival. The inhibitors of mTOR as anticancer reagents are undergoing active evaluation in various malignancies including breast cancer. However, the activation status of the Akt/mTOR/4E-BP1 pathway and its potential roles in breast cancers remain unknown. Thus, we examined 165 invasive breast cancers with specific antibodies for the phosphorylation of Akt, mTOR, and 4E-BP1 by immunohistochemistry and compared them with normal breast epithelium, fibroadenoma, intraductal hyperplasia, and ductal carcinoma in situ. We discovered that the phosphorylation of Akt, mTOR, and 4E-BP1 increased progressively from normal breast epithelium to hyperplasia and abnormal hyperplasia to tumor invasion. Phosphorylated Akt, mTOR, and 4E-BP1 were positively associated with ErbB2 overexpression. Survival analysis showed that phosphorylation of each of these three markers was associated with poor disease-free survival independently. In vitro, we further confirmed the causal relationship between ErbB2 overexpression and mTOR activation, which was associated with enhanced invasive ability and sensitivity to a mTOR inhibitor, rapamycin. Our results, for the first time, demonstrate the following: (a) high levels of phosphorylation of Akt, mTOR, and 4E-BP1 in breast cancers, indicating activation of the Akt/mTOR/4E-BP1 pathway in breast cancer development and progression; (b) a link between ErbB2 and the Akt/mTOR/4E-BP1 pathway in breast cancers in vitro and in vivo, indicating the possible role of Akt/mTOR activation in ErbB2-mediated breast cancer progression; and (c) a potential role for this pathway in predicting the prognosis of patients with breast cancer, especially those treated with mTOR inhibitors.     

胃癌患者Hp感染及血清GPDA活性的变化

目的探讨胃癌患者粪便Hp检出率与血清GPDA活性变化的关系。方法利用幽门螺旋杆菌粪便抗原检测法(HpSA法)和速率法分别检测117例初治前胃癌患者、45例良性胃部疾病患者及40例正常人粪便中的Hp阳性率和血清GPDA活性并作相关分析。结果胃癌患者Hp感染率及其血清GPDA的阳性率分别为70.1%和71.5%,显著高于良性胃部疾病患者和正常人(P<0.01)。胃癌的部位与Hp感染有关(P<0.05),而其血清GPDA活性与临床各因素的关系并不密切(P>0.05),两者无相关性(P>0.01)。结论Hp感染可能与胃癌的发生、发展有关,血清GPDA检测对胃癌的诊断有一定的意义。