Prevalence of Helicobacter pylori vacA, cagA, cagE, iceA and babA2 genotypes in Thai dyspeptic patients.

OBJECTIVES: To investigate the prevalence of the vacA, cagA, cagE, iceA, and babA2 genotypes in Helicobacter pylori strains isolated from Thai dyspeptic patients, and to determine whether any correlation exists between these genotypes and clinical manifestations. METHODS: Helicobacter pylori was examined in 112 patients (62 with non-ulcer dyspepsia (gastritis), 34 with peptic ulcer disease, and 16 with gastric cancer (GCA)), detected by culture or direct detection from gastric biopsies. Allelic variants of the vacA, cagA, cagE, iceA, and babA2 genotypes were identified by using the polymerase chain reaction. RESULTS: The positive rates for the vacAs1, vacAs2, cagA, cagE, iceA1, iceA2, and babA2 genes in H. pylori of dyspeptic patients were 100%, 0%, 98.2%, 88.4%, 45.5%, 33.1%, and 92%, respectively. The allelic variant vacAs1m1 was more prevalent (58%) than vacAs1m2 (42%). The cagA and cagE genes were commonly found together (87.5%). The most predominant genotypes were vacAs1m1, cagA, cagE, iceA1, and babA2. The various genes alone or in combination had no statistically significant association with the clinical outcomes (p>0.05). CONCLUSION: Neither single gene nor combination of vacA, cagA, cagE, iceA, and babA2 genes was significantly helpful in predicting the clinical outcome of H. pylori infection in Thai patients. The high prevalence of these genes in H. pylori isolated from Thai patient groups suggests that H. pylori strains are geographically dependent.     

Immunosuppressive Prednisolone Enhances Early Cholangiocarcinoma in Syrian Hamsters with Liver Fluke Infection and Administration of N-nitrosodimethylamine

Chronic infection with Opisthorchis viverrini for many years has been associated with the development of hepatobiliary diseases including cholangiocarcinoma. It is well known that inflammation is a key component of the tumor microenvironment, and that chronic inflammation plays an important role in tumorigenesis. Therefore, in this study cholangiocarcinogenesis was induced in Syrian hamsters in order to observe the cancer-related inflammation. The Syrian hamsters were divided into 5 groups: uninfected controls; normal Syrian hamsters infected with O. viverrini (OV); immunosuppressed Syrian hamsters infected with O. viverrini (OVis); normal Syrian hamsters infected with O. viverrini and administered N-nitrosodimethylamine (CCA); and immunosuppressed Syrian hamsters infected with O. viverrini and administered N-nitrosodimethylamine (CCAis). Syrian hamster livers were later observed for gross pathology and histopathological changes; COX2 was analyzed by immunohistochemical staining. We found a decreased number of inflammatory cells surrounding the hepatic bile duct in the OVis group, but not in the OV and CCAis groups. However, in the CCAis group (with suppressed immunity) early appearance and greater severity of cholangiocarcinoma were observed; gross pathological examination revealed many cancer nodularities on the liver surface, and histopathological studies showed the presence of cancer cells, findings which correlated with the predominant expression of COX2. The present study suggests that host immune responses are intended to ameliorate pathology, and they are also crucially associated with pathogenesis in O. viverrini infection; the unbalancing of host immunity may enhance cancer-related inflammation.     

Mechanisms of oxysterol-induced carcinogenesis

Oxysterols are oxidation products of cholesterol that are generated by enzymatic reactions mediated by cytochrome P450 family enzymes or by non-enzymatic reactions involving reactive oxygen and nitrogen species. Oxysterols play various regulatory roles in normal cellular processes such as cholesterol homeostasis by acting as intermediates in cholesterol catabolism. Pathological effects of oxysterols have also been described, and various reports have implicated oxysterols in several disease states, including atherosclerosis, neurological disease, and cancer. Numerous studies show that oxysterols are associated with various types of cancer, including cancers of the colon, lung, skin, breast and bile ducts. The molecular mechanisms whereby oxysterols contribute to the initiation and progression of cancer are an area of active investigation. This review focuses on the current state of knowledge regarding the role of oxysterols in carcinogenesis. Mutagenicity of oxysterols has been described in both nuclear and mitochondrial DNA. Certain oxysterols such as cholesterol-epoxide and cholestanetriol have been shown to be mutagenic and genotoxic. Oxysterols possess pro-oxidative and pro-inflammatory properties that can contribute to carcinogenesis. Oxysterols can induce the production of inflammatory cytokines such as interleukin-8 and interleukin-1β. Certain oxysterols are also involved in the induction of cyclo-oxygenase-2 expression. Inflammatory effects can also be mediated through the activation of liver-X-receptor, a nuclear receptor for oxysterols. Thus, several distinct molecular mechanisms have been described showing that oxysterols contribute to the initiation and progression of cancers arising in various organ systems.     

The Importance of CYP19A1 in Estrogen Receptor-Positive Cholangiocarcinoma

CYP19A1, also called aromatase, is a key enzyme for converting androgens to estrogens of estrogen synthesis. Elevated serum estrogen and high expression levels of estrogen-related proteins are found in cholangiocarcinoma (CCA; bile duct cancer). However, the expression of CYP19A1 in relation to estrogen-related proteins, including estrogen receptors (ERα, ERβ, and GPR30) and an estrogen response protein (TFF1), has never been explored in CCA. In this study, we investigated the expressions of CYP19A1 and estrogen-related proteins in CCA tissues (n?=?74; 51 males and 23 females) using immunohistochemistry. The results showed that CYP19A1 was overexpressed in CCA cells compared with that in normal bile duct cells in the adjacent tissues. High expression of CYP19A1 was correlated with the metastatic status of the patients. High CYP19A1 expression was also positively correlated with GPR30 expression. Correlation between high CYP19A1 expression in the tumor tissues and shorter survival time was more prominent in male than in female CCA patients. To elucidate further, the effect of CYP19A1 knockdown on a CCA cell line was examined using a specific siRNA. When CYP19A1 gene expression was suppressed, migration and proliferation activities of CCA cells were significantly reduced. Moreover, the cell proliferation of high CYP19A1-expressing KKU-213 cells was more profoundly suppressed by CYP19A1 inhibitors (exemestane and letrozole) than low CYP19A1-expressing KKU-100 cells. Thus, CYP19A1 promotes CCA progression with aggressive clinical outcomes via increased migration and proliferation activities of cancer cells. CYP19A1 can be a potential chemotherapeutic target for CCA, especially in male patients.     

Increased EphB2 expression predicts cholangiocarcinoma metastasis

The activation of Ephrin (Eph) receptors, the largest tyrosine kinase families of cell surface receptor, has recently been addressed in human cholangiocarcinoma (CCA). Therefore, the present study aimed to investigate the role of Eph receptors and its ligands in CCA. Of all 50 cases of human CCA tested, immunohistochemical staining demonstrated that EphB2, EphB4, ephrinB1, and ephrinB2 were 100 % positive in CCA tissues with overexpressions of the above proteins as 56, 56, 70, and 48 % of cases, respectively. High expression of EphB2 was significantly correlated with the metastatic status of patients (P?=?0.027). We also found that the high co-expression level of EphB2/ephrinB1 or EphB2/ephrinB2 were significantly correlated with the metastatic status of the patients (P?=?0.034 and P?=?0.024). Furthermore, we showed that the high co-expression level of EphB4/MVD and ephrinB1/MVD were significantly correlated with the metastasis status of CCA patients (P?=?0.012 and P?=?0.029). We further demonstrated that the EphB2 suppression using siRNA significantly reduced CCA cell migration by decreasing the phosphorylation of focal adhesion kinase (FAK) and paxillin. In conclusion, the upregulation of EphB2 receptors and its specific ligands (ephrinB1 and ephrinB2) leads to CCA metastasis. Suppression of EphB2 expression as well as inhibition of its downstream signaling proteins might serve as possible therapeutic strategies in human CCA.