Nitric oxide confers cisplatin resistance in human lung cancer cells through upregulation of aldo-keto reductase 1B10 and proteasome.

In this study, we show that exposure of human lung cancer A549 cells to cisplatin (cis-diamminedichloroplatinum, CDDP) promotes production of nitric oxide (NO) through generation of reactive oxygen species (ROS) and resulting upregulation of inducible NO synthase (iNOS). The incubation of the cells with a NO donor, diethylenetriamine NONOate, not only reduced the CDDP-induced cell death and apoptotic alterations (induction of CCAAT-enhancer-binding protein homologous protein and caspase-3 activation), but also elevated proteolytic activity of 26S proteasome, suggesting that the activation of proteasome function contributes to the reduction of CDDP sensitivity by NO. Monitoring expression levels of six aldo-keto reductases (AKRs) (1A1, 1B1, 1B10, 1C1, 1C2, and 1C3) during the treatment with the NO donor and subsequent CDDP sensitivity test using the specific inhibitors also proposed that upregulation of AKR1B10 by NO is a key process for acquiring the CDDP resistance in A549 cells. Treatment with CDDP and NO increased amounts of nitrotyrosine protein adducts, indicative of peroxynitrite formation, and promoted the induction of AKR1B10, inferring a relationship between peroxynitrite formation and the enzyme upregulation in the cells. The treatment with CDDP or a ROS-related lipid aldehyde, 4-hydroxy-2-nonenal, facilitated the iNOS upregulation, which was restored by increasing the AKR1B10 expression. In contrast, the facilitation of NO production by CDDP treatment was hardly observed in AKR1B10-overexpressing A549 cells and established CDDP-resistant cancer cells (A549, LoVo, and PC3). Collectively, these results suggest the NO functions as a key regulator controlling AKR1B10 expression and 26S proteasome function leading to gain of the CDDP resistance.

First case report of de novo ulcerative colitis developing after orthotopic liver transplantation successfully treated by granulocyte and monocyte apheresis.

BACKGROUND: Immunosuppressants such as tacrolimus and cyclosporine are prescribed long-term after orthotopic liver transplantation (OLT) to prevent allograft rejection. Although these immunosuppressants are known to effectively control ulcerative colitis (UC), some post-OLT patients develop exacerbation of preexisting UC or de novo UC. Although aminosalicylates and corticosteroid courses are usually effective to treat such UC, several patients have developed uncontrollable disease and required colectomies. CASE REPORT: We have reported a patient who developed de novo UC after OLT to treat liver cirrhosis and hepatocellular carcinoma associated with hepatitis B virus (HBV) infection. Existence of the HBV infection made us avoid to increase the corticosteroid dose or to use other immunosuppressants such as azathioprine or infliximab. CONCLUSIONS: In this patient, granulocyte and monocyte apheresis was highly effective in terms of inducing remission of de novo UC. No adverse event was noted.

Cloning and characterization of the antigenic membrane protein (Amp) gene and in situ detection of Amp from malformed flowers infected with Japanese hydrangea phyllody phytoplasma.

A Japanese hydrangea phyllody (JHP) disease found throughout Japan causes economic damage to the horticultural industry. JHP phytoplasma-infected Japanese hydrangea plants show several disease symptoms involved in floral malformations, such as virescence, phyllody and proliferation. Here, we cloned and characterized the antigenic membrane protein (Amp) gene homolog from the JHP phytoplasma (JHP-amp), expressed the JHP-Amp protein in Escherichia coli cells, and then obtained an antibody against JHP-Amp. The antibody against JHP-Amp had no cross-reactions with the antibody against the Amp protein from a closely related onion yellows phytoplasma. This serologic specificity is probably due to the high diversity of the hydrophilic domains in the Amp proteins. The in situ detection of the JHP-Amp protein revealed that the JHP phytoplasma was localized to the phloem tissues in the malformed flower. This study shows that the JHP-Amp protein is indeed a membrane protein, which is expressed at detectable level in the JHP phytoplasma-infected hydrangea.

Nucleotide sequence analysis of seven Japanese isolates of Plantago asiatica mosaic virus (PlAMV): a unique potexvirus with significantly high genomic and biological variability within the species.

The genomic sequences of Plantago asiatica mosaic virus (PlAMV), six lily isolates and one primrose isolate from Japan, were determined. The genomic size of all isolates was 6102 nucleotides, containing the five open reading frames typical of members of the genus Potexvirus. Pairwise comparison analyses confirmed the close relationship between PlAMV and tulip virus X. However, quite low identities were observed between different PlAMV isolates, including foreign isolates; nucleotide sequence identities of the RNA-dependent RNA polymerase (RdRp) gene between a Russian isolate (PlAMV-Ru), a Nandina isolate (PlAMV-Na) and Japanese isolates were 75-77%. These values were the lowest amongst different isolates of the same species of any potexviruses.

Genome sequence of a Japanese isolate of Radish mosaic virus: the first complete nucleotide sequence of a crucifer-infecting comovirus.

The complete nucleotide sequences of RNA1 and RNA2 of a Japanese isolate of Radish mosaic virus (RaMV-J), a crucifer-infecting comovirus, were determined. RNA1 is 6064 nucleotides long and encodes a 210-kDa polyprotein containing conserved motifs that are required for replication. RNA2 is 4020 nucleotides long and encodes a 123-kDa polyprotein containing the putative movement protein and two coat proteins. Comparisons of the encoded proteins confirmed that RaMV-J and a Czech RaMV isolate are isolates of the same species in the genus Comovirus. A phylogenetic analysis of RaMV-J and other comoviruses revealed that legume-infecting comoviruses constitute a single branch to which RaMV is distantly related.

CagA protein secreted by the intact type IV secretion system leads to gastric epithelial inflammation in the Mongolian gerbil model.

Helicobacter pylori causes various gastro-duodenal diseases, including gastric cancer. The CagA protein, an H. pylori virulence factor, induces morphological changes in host cells and may be associated with the development of peptic ulcer and gastric carcinoma. The present study has analysed the role of CagA protein in the pathogenesis of H. pylori infection in the Mongolian gerbil model. Mongolian gerbils were challenged with wild-type H. pylori strain TN2, which has a functional cag pathogenicity island or isogenic mutants with disrupted cagA (DeltacagA) or cagE (DeltacagE) genes. They were sacrificed at 7, 13, and 25 weeks after inoculation. Pathological changes of the gastric mucosa were determined and apoptosis was assessed by the TUNEL assay. Immunohistochemistry for PCNA, phospho-IkappaBalpha, and phospho-Erk was also performed. All of the bacterial strains colonized the gerbil stomach at similar densities; however, the DeltacagA mutant induced milder gastritis than did the wild type. The extent of apoptosis and lymphoid follicle formation in the epithelium appeared to depend on intact cagA. The DeltacagA mutant induced less phosphorylation of IkappaBalpha and Erk, and less expression of interferon-gamma and interleukin-1beta mRNA in the epithelium than did the wild type. It is concluded that CagA protein may be essential for the induction of severe gastritis in the Mongolian gerbil model.

Gastric cancer among peptic ulcer patients: retrospective, long-term follow-up.

BACKGROUND: Patients with duodenal ulcer are not at high risk although Helicobacter pylori infection is no doubt associated with gastric cancer development. However, little is known about the risk after long-term follow-up. AIMS: We investigated the incidence for gastric cancer development in peptic ulcer patients in a long term. PATIENTS AND METHODS: Between 1965 and 2004, endoscopic follow-up of more than 1 year was conducted on 1504 peptic ulcer patients in our hospital. They consisted of 978 gastric ulcer patients, 444 duodenal ulcer patients and 82 gastric and duodenal ulcer patients. Gastric and duodenal ulcer patients were excluded from the analysis because of their limited number. RESULTS: Gastric cancers developed in 32 (3.3%) of gastric ulcer patients and 3 (0.68%) of duodenal ulcer patients. Kaplan-Meier analysis showed that the incidence of gastric cancer in duodenal ulcer patients was significantly lower than that in gastric ulcer patients (log-rank test, p=0.0059). Cox's proportional hazard model denoted the relative risk for duodenal ulcer against gastric ulcer adjusted by sex and age as 0.23 (95% CI: 0.072-0.77, p=0.016). CONCLUSION: The risk for patients with duodenal ulcer to develop gastric cancer over the long term is significantly less than in those with gastric ulcer.

A single amino acid in the RNA-dependent RNA polymerase of Plantago asiatica mosaic virus contributes to systemic necrosis.

From a lily isolate of Plantago asiatica mosaic virus (PlAMV-Li), two sub-isolates (Li1 and Li6) were obtained. Although the nucleotide sequences of Li1 and Li6 were highly conserved, they showed different pathogenicity in Nicotiana benthamiana. Li1 caused necrosis, whereas Li6 infected the plant asymptomatically. Inoculation tests with chimeric and point-mutated viruses revealed that amino acid 1154 of the RNA-dependent RNA polymerase (RdRp) contributes to the necrotic symptoms. The accumulation of the mutant viruses, in which amino acid 1154 of the RdRp was exchanged to the wild-type codon in Li1 and Li6, was almost equal.

Predicting the development of gastric cancer from combining Helicobacter pylori antibodies and serum pepsinogen status: a prospective endoscopic cohort study.

BACKGROUND AND AIMS: Helicobacter pylori infection and gastric atrophy are both risk factors for gastric cancer. We aimed to elucidate the natural history of gastric cancer development according to H pylori infection and gastric atrophy status. SUBJECTS AND METHODS: A total of 9293 participants in a mass health appraisal programme were candidates for inclusion in the present prospective cohort study: 6983 subjects revisited the follow up programme. Subjects were classified into four groups according to serological status at initial endoscopy. Group A (n = 3324) had "normal" pepsinogen and were negative for H pylori antibody; group B (n = 2134) had "normal" pepsinogen and were positive for H pylori antibody; group C (n = 1082) had "atrophic" pepsinogen and were positive for H pylori antibody; and group D (n = 443) had "atrophic" pepsinogen and were negative for H pylori antibody. Incidence of gastric cancer was determined by annual endoscopic examination. RESULTS: Mean duration of follow up was 4.7 years and the average number of endoscopic examinations was 5.1. The annual incidence of gastric cancer was 0.04% (95% confidence interval (CI) 0.02-0.09), 0.06% (0.03-0.13), 0.35% (0.23-0.57), and 0.60% (0.34-1.05) in groups A, B, C, and D, respectively. Hazard ratios compared with group A were 1.1 (95% CI 0.4-3.4), 6.0 (2.4-14.5), and 8.2 (3.2-21.5) in groups B, C, and D, respectively. Age, sex, and "group" significantly served as independent valuables by multivariate analysis. CONCLUSIONS: The combination of serum pepsinogen and anti-H pylori antibody provides a good predictive marker for the development of gastric cancer.