Makoto Ichiba

A central role for Stat3 in IL-6-induced regulation of growth and differentiation in M1 leukemia cells.

Interleukin‐6 (IL‐6) induces either differentiation or growth of a variety of cells. Little is known about the molecular basis of this cellular decision. The family of signal transducer and activator of transcription (Stat) proteins are involved in signaling through a variety of cytokine and growth factor receptors, although their biological roles have not been established. To address whether Stat proteins play roles in IL‐6‐induced growth or differentiation, we introduced two types of mutant Stat3 acting in a dominant‐negative manner into M1 leukemic cells which respond to IL‐6 with growth arrest and terminal differentiation. We show that dominant‐negative forms of Stat3 inhibited both IL‐6‐induced growth arrest at G(0)/G1 and macrophage differentiation in the M1 transformants. Blocking of Stat activation resulted in inhibition of IL‐6‐induced repression of c‐myb and c‐myc. Furthermore, IL‐6 enhanced the growth of M1 cells primarily through shortening the length of the G1 period when Stat3 was suppressed. Thus IL‐6 generates both growth‐enhancing signals and growth arrest‐ and differentiation‐inducing signals at the same time. Stat3 may be a key molecule which determines the cellular decision from cell growth to differentiation in M1 cells.

AUTOREGULATION OF THE STAT3 GENE THROUGH COOPERATION WITH A CAMP-RESPONSIVE ELEMENT-BINDING PROTEIN

STAT3 (signal transducer and activator of transcription 3) is a key transcription factor mediating the signals for a variety of cytokines, including interleukin-6 (IL-6). The Stat3 gene itself is activated by IL-6 signals. We show that the region of the signal-transducing subunit, gp130, essential for STAT3 activation, is also required for activation of the Stat3 gene. To elucidate the mechanisms activating the Stat3 gene, we identified an IL-6 response element (IL-6RE) in the Stat3gene promoter containing both a low affinity STAT3-binding element and a cAMP-responsive element (CRE). Electrophoretic mobility shift assays showed that IL-6 induced a slowly migrating complex on the IL-6RE containing a STAT3 homodimer and an unidentified CRE-binding protein. With the combination of transient transfection assays using mutantStat3 promoter-reporter constructs and electrophoretic mobility shift assays, we found that the formation of a slowly migrating complex was required for full activation of theStat3 gene. Thus, STAT3 activates the Stat3gene in cooperation with an unidentified CRE-binding protein. This regulatory mechanism is similar to that of the junB gene, which is activated by IL-6 through the junB IL-6RE, which contains a low affinity STAT3-binding site and a CRE-like site.

SHORT-TERM OUTCOMES OF ENDOSCOPIC SUBMUCOSAL DISSECTION (ESD) FOR EARLY GASTRIC NEOPLASM: MULTICENTER SURVEY BY OSAKA UNIVERSITY ESD STUDY GROUP

Background:  Endoscopic submucosal dissection (ESD) was developed for en bloc removal of large and flat gastrointestinal tract neoplasms. In Japan, ESD is performed under conscious sedation. The risks for sedation‐related complications of ESD, such as postoperative pneumonia, have not been evaluated. The aim of this study was to evaluate the incidence of postoperative pneumonia after ESD in a multicenter survey.

Epidermal growth factor inhibits the growth of TE8 esophageal cancer cells through the activation of STAT1

Background:Background: Epidermal growth factor receptors (EGFRs) mediate growth signals in a variety of normal and malignant cells. However, the issue of whether the EGF/EGFR system contributes to the progression of esophageal cancer cells remains controversial. The aim of the present study was to determine the role of EGFR in the growth of esophageal cancer cell lines. Methods: Three esophageal cancer cell lines, TE1, TE2, and TE8, were stimulated with EGF, and cellular growth was then evaluated by cell number. The activation of signal transducers and activators of transcription (STATs) and the expression of the cyclin-dependent kinase (CDK) inhibitor p21/WAF1 were determined by an electromobility shift assay and Northern blot analysis, respectively. Results: EGF inhibited the growth of TE8 cells, while no significant effects were observed for TE1 and TE2 cells. The treatment of TE8 cells with EGF induced the activation of STAT1 and STAT3, followed by the expression of p21/WAF1. The introduction of a dominant-negative STAT1 construct into TE8 cells abolished not only growth inhibition but also p21/WAF1 induction by EGF. Conclusions: The findings herein suggest that EGF inhibits the growth of some esophageal cancer cells that overexpress EGFR and that the activation of STAT1 constitutes a critical event which is required for the inhibition of growth by EGF.

Comparative study of esomeprazole and lansoprazole in triple therapy for eradication of Helicobacter pylori in Japan

AIM To evaluate the efficacy and safety of esomeprazole-based triple therapy compared with lansoprazole therapy as first-line eradication therapy for patients with Helicobacter pylori (H. pylori) in usual post-marketing use in Japan, where the clarithromycin (CAM) resistance rate is 30%. METHODS For this multicenter, randomized, open-label, non-inferiority trial, we recruited patients (≥ 20 years of age) with H. pylori infection from 20 hospitals in Japan. We randomly allocated patients to esomeprazole therapy (esomeprazole 20 mg, CAM 400 mg, amoxicillin (AC) 750 mg for the first 7 d, with all drugs given twice daily) or lansoprazole therapy (lansoprazole 30 mg, CAM 400 mg, AC 750 mg for the first 7 d, with all drugs given twice daily) using a minimization method with age, sex, and institution as adjustment factors. Our primary outcome was the eradication rate by intention-to-treat (ITT) and per-protocol (PP) analyses. H. pylori eradication was confirmed by a urea breath test from 4 to 8 wk after cessation of therapy. RESULTS ITT analysis revealed the eradication rates of 69.4% (95%CI: 61.2%-76.6%) for esomeprazole therapy and 73.9% (95%CI: 65.9%-80.6%) for lansoprazole therapy (P = 0.4982). PP analysis showed eradication rate of 76.9% (95%CI: 68.6%-83.5%) for esomeprazole therapy and 79.8% (95%CI: 71.9%-86.0%) for lansoprazole therapy (P = 0.6423). There were no differences in adverse effects between the two therapies. CONCLUSION Esomeprazole showed non-inferiority and safety in a 7 day-triple therapy for eradication of H. pylori compared with lansoprazole.

Tu1064 Esomeprazole Versus Lansoprazole in Triple Therapy for Eradication of Helicobacter pylori in Japan: A Multicenter, Randomized Study by the Osaka Gut Forum

G A A b st ra ct s ethical committee and written informed consent was obtained from all patients. Subjects randomly assigned to three treatment groups for 10 days: Standard triple therapy (STT), Esomeprazole (40 mg b.i.d.) + clarithromycin (500 mg b.id.) + amoxicillin (1,000 mg b.i.d.). Levofloxacin triple therapy (LTT): Esomeprazole (40 mg b.i.d.) + levofloxacin (500 mg once a day) + amoxicillin (1,000 mg b.i.d.) and Levo-Clari triple therapy LCT: Esomeprazole (40 mg b.i.d.) + clarithromycin ((500mg b.i.d.) + levofloxacin (500mg once a day). The allocation was concealed. All were H. pylori positive. Antimicrobial susceptibility was determined by agar dilution and by direct sequencing of PCR products. Post treatment H. pylori status was determined by the 13C-UBT at least 8 weeks after the completion of treatment. The results and analysis of clinical trial was by intention-to-treat (ITT) and per-protocol (PP). Results 240 patients were enrolled between February 2008 and February 2011, 80 patients in each treatment group. ITT results were: STT 71% (95% CI 61% 82%), LTT 75% (95% CI 65% -85%) and LCT 79% (95% CI 70% -91%). PP results were 71%, 75% and 83%, respectively (p = n.s.) The most common mutation resulting in clari resistance was A2143G, and for levofloxacin, mutations D91G, N87K and N871. The relative risk (RR) of failure in relation to specific mutations were: for 23S rRNA in STT 6 and 2.9 for LCT. The (RR) for presence of mutations in both gene gyrA and 23S rRNA in LTT was 14. We performed a logistic regression model to estimate the probability of treatment success. The model variables were associated with the presence of A2143G mutation, N87I, D91G. The probability of treatment success in patients without mutation was 98% compared to 13% for those with mutations in both genes. Adverse events occurred in all three treatment groups and were mild or moderate, with no residual effects. Metallic taste was the most common adverse effect, followed by diarrhea, abdominal pain and nausea. 2 patients required stopping treatment for diarrhea in the LCT group. Conclusion Triple standard therapy and triple therapies containing levofloxacin no provided acceptable cure rates in Bogota because of high rates of clarithromycin and levofloxacin resistance.