No abstract

IL-18 and IL-18 binding protein (IL-18BP) are two newly described opponents in the cytokine network. Local concentrations of these two players may determine biological functions of IL-18 in the context of inflammation, infection, and cancer. As IL-18 appears to be involved in the pathogenesis of Crohn’s disease and may modulate tumor growth, we investigated the IL-18/IL-18BPa system in the human colon carcinoma/epithelial cell line DLD-1. In this study, we report that IFN-γ induces expression and release of IL-18BPa from DLD-1 cells. mRNA induction and secretion of IL-18BPa immunoreactivity were associated with an activity that significantly impaired release of IFN-γ by IL-12/IL-18-stimulated PBMC. Inducibility of IL-18BPa by IFN-γ was also observed in LoVo, Caco-2, and HCT116 human colon carcinoma cell lines and in the human keratinocyte cell line HaCaT. Induction of IL-18BPa in colon carcinoma/epithelial cell lines was suppressed by coincubation with sodium butyrate. IFN-γ-mediated IL-18BPa and its suppression by sodium butyrate were confirmed in organ cultures of intestinal colonic biopsy specimens. In contrast, sodium butyrate did not modulate expression of IL-18. The present data suggest that IFN-γ may limit biological functions of IL-18 at sites of colonic immune activation by inducing IL-18BPa production. Down-regulation of IL-18BPa by sodium butyrate suggests that reinforcement of local IL-18 activity may contribute to actions of this short-chain fatty acid in the colonic microenvironment.

The sensitivity of 18F-FDG PET for the imaging of HCC is low. Nevertheless, in patients with moderately or poorly differentiated HCC, tumors >5 cm, or with markedly elevated AFP levels 18F-FDG PET may contribute to an effective noninvasive staging.

Although the antiviral effects of amantadine sulphate (1-aminoadamantan sulphate) have not been characterized for the hepatitis C virus (HCV), previous pilot studies have suggested promising results in patients with chronic hepatitis C. The aim of the present study was to compare the efficacy, safety, and health-related quality of life (HRQOL) of interferon alfa (IFN-␣) alone or in combination with oral amantadine for treatment of chronic hepatitis C. One hundred nineteen previously untreated patients with chronic hepatitis C were randomly allocated to treatment with IFN␣2a at a dose of 6 megaunits 3 times a week subcutaneously for 24 weeks, followed by 3 megaunits thrice weekly for an additional 24 weeks plus amantadine sulphate administered orally 100 mg twice a day for 48 weeks or the same IFN regimen plus a matched placebo. The primary endpoint was undectable serum HCV RNA (<1,000 copies/mL) at week 24 after treatment. Hepatitis C virus (HCV) infection often progresses to chronic hepatitis, cirrhosis, and possibly hepatocellular carcinoma. 1 Chronic hepatitis C infection is a leading cause of chronic liver disease and the most common indication for liver transplantation. Treatment of HCV-infected patients with interferon alfa (IFN-␣) can achieve viral clearance and improve histology and prognosis. However, the overall sustained virologic response to IFN-␣ monotherapy is less than 20%. 2,3 Recent studies investigating the efficacy of combination therapy with IFN-␣ and ribavirin in patients with chronic hepatitis C, showed improved sustained virologic response rates of approximately 40%. 4,5 Nevertheless, further improvements in the treatment of chronic hepatitis C are still needed.Amantadine (1-aminoadamantan) is a tricyclic amine with antiviral activity against toga-, myxo-, arena-, flavi-, and coronaviruses. 6-10 Inhibition of influenza A virus replication by amantadine is clinically well characterized. 11 The molecular mechanisms include inhibition of an early step in viral replication, most likely viral uncoating and interaction with the viral M2 protein, which is a membrane-bound protein thought to be important in virus budding. 12,13 Although antiviral effects of amantadine have not been characterized for the hepatitis C virus, promising results have been reported in several pilot studies of HCV-infected patients treated with amantadine alone [14][15][16] or in combination with IFN-␣. 15,17 The aim of this study was to compare efficacy, safety, and health-related quality of life (HRQOL) of therapy with IFN␣2a alone and in combination with oral amantadine sulphate, administered for 48 weeks for the treatment of chronic HCV infection in patients who have not previously been treated with IFN, ribavirin, and/or amantadine. PATIENTS AND METHODSPatients. Men and women aged 18 to 70 years with compensated chronic HCV infection not previously treated with IFN, ribavirin, and/or amantadine were eligible for enrollment. Eligible patients tested positive for anti-HCV (second-generation enzyme immunoassay) and HCV ...

MutLα, a heterodimer of MLH1 and PMS2, plays a central role in human DNA mismatch repair. It interacts ATP-dependently with the mismatch detector MutSα and assembles and controls further repair enzymes. We tested if the interaction of MutLα with DNA-bound MutSα is impaired by cancer-associated mutations in MLH1, and identified one mutation (Ala128Pro) which abolished interaction as well as mismatch repair activity. Further examinations revealed three more residues whose mutation interfered with interaction. Homology modelling of MLH1 showed that all residues clustered in a small accessible surface patch, suggesting that the major interaction interface of MutLα for MutSα is located on the edge of an extensive β-sheet that backs the MLH1 ATP binding pocket. Bioinformatic analysis confirmed that this patch corresponds to a conserved potential protein–protein interaction interface which is present in both human MLH1 and its E.coli homologue MutL. MutL could be site-specifically crosslinked to MutS from this patch, confirming that the bacterial MutL–MutS complex is established by the corresponding interface in MutL. This is the first study that identifies the conserved major MutLα–MutSα interaction interface in MLH1 and demonstrates that mutations in this interface can affect interaction and mismatch repair, and thereby can also contribute to cancer development.

Background: Anti-angiogenic treatment is believed to have at least cystostatic effects in highly vascularized tumours like pancreatic cancer. In this study, the treatment effects of the angiogenesis inhibitor Cilengitide and gemcitabine were compared with gemcitabine alone in patients with advanced unresectable pancreatic cancer.

Background-In some patients with primary biliary cirrhosis, ursodeoxycholic acid causes full biochemical normalisation of laboratory data; in others, indexes improve but do not become normal. Aims-To characterise complete and incomplete responders. Methods-Seventy patients with primary biliary cirrhosis were treated with ursodeoxycholic acid 10-15 mg/kg/day and followed up for 6-13 years. Results-In 23 patients (33%) with mainly stage I or II disease, cholestasis indexes and aminotransferases normalised within 1-5 years, except for antimitochondrial antibodies. Histological findings improved. Indexes were not normalised in 47 patients (67%) although the improvement of their biochemical functions parallelled the trend in the first group. In these incomplete responders histological findings improved to a lesser extent. The only diVerence between the two groups before treatment was higher levels of alkaline phosphatase and glutamyl transpeptidase in the incomplete responders. At onset of treatment the discriminant value separating responders from incomplete responders was 660 U/l for alkaline phosphatase and 131 U/l for glutamyl transpeptidase. One year later it was 239 and 27 U/l (overall predictive value for responders 92%, for incomplete responders 81%). There were no diVerences between the two groups concerning immune status, antimitochondrial antibody subtypes, liver histology, or any other data. HLA-B39, DRB1*08, DQB1*04 dominated in both groups. Conclusions-In patients with mainly early stages of primary biliary cirrhosis, higher values of alkaline phosphatase and glutamyl transpeptidase are the only biochemical indexes which allow discrimination between patients who will completely or incompletely respond to ursodeoxycholic acid treatment. (Gut 2000;46:121-126)

Mismatch repair is a highly conserved system that ensures replication fidelity by repairing mispairs after DNA synthesis. In humans, the two protein heterodimers hMutSalpha (hMSH2-hMSH6) and hMutLalpha (hMLH1-hPMS2) constitute the centre of the repair reaction. After recognising a DNA replication error, hMutSalpha recruits hMutLalpha, which then is thought to transduce the repair signal to the excision machinery. We have expressed an ATPase mutant of hMutLalpha as well as its individual subunits hMLH1 and hPMS2 and fragments of hMLH1, followed by examination of their interaction properties with hMutSalpha using a novel interaction assay. We show that, although the interaction requires ATP, hMutLalpha does not need to hydrolyse this nucleotide to join hMutSalpha on DNA, suggesting that ATP hydrolysis by hMutLalpha happens downstream of complex formation. The analysis of the individual subunits of hMutLalpha demonstrated that the hMutSalpha-hMutLalpha interaction is predominantly conferred by hMLH1. Further experiments revealed that only the N-terminus of hMLH1 confers this interaction. In contrast, only the C-terminus stabilised and co-immunoprecipitated hPMS2 when both proteins were co-expressed in 293T cells, indicating that dimerisation and stabilisation are mediated by the C-terminal part of hMLH1. We also examined another human homologue of bacterial MutL, hMutLbeta (hMLH1-hPMS1). We show that hMutLbeta interacts as efficiently with hMutSalpha as hMutLalpha, and that it predominantly binds to hMutSalpha via hMLH1 as well.