Toshimitsu Yamaoka

Transactivation of EGF receptor and ErbB2 protects intestinal epithelial cells from TNF-induced apoptosis.

TNF is a pleiotropic cytokine that activates both anti- and proapoptotic signaling pathways, with cell fate determined by the balance between these two pathways. Activation of ErbB family members, including EGF receptor (EGFR/ErbB1), promotes cell survival and regulates several signals that overlap with those stimulated by TNF. This study was undertaken to determine the effects of TNF on EGFR and ErbB2 activation and intestinal epithelial cell survival. Mice, young adult mouse colon epithelial cells, and EGFR knockout mouse colon epithelial cells were treated with TNF. Activation of EGFR, ErbB2, Akt, Src, and apoptosis were determined in vivo and in vitro. TNF stimulated EGFR phosphorylation in young adult mouse colon epithelial cells, and loss of EGFR expression or inhibition of kinase activity increased TNF-induced apoptosis, which was prevented in WT but not by kinase-inactive EGFR expression. Similarly, TNF injection stimulated apoptosis in EGFR-kinase-defective mice (EGFRwa2) compared with WT mice. TNF also activated ErbB2, and loss of ErbB2 expression increased TNF-induced apoptosis. Furthermore, Src-kinase activity and the expression of both EGFR and ErbB2 were required for TNF-induced cell survival. Akt was shown to be a downstream target of TNF-activated EGFR and ErbB2. These findings demonstrate that EGFR and ErbB2 are critical mediators of TNF-regulated antiapoptotic signals in intestinal epithelial cells. Given evidence for TNF signaling in the development of colitis-associated carcinoma, this observation has significant implications for understanding the role of EGFR in maintaining intestinal epithelial cell homeostasis during cytokine-mediated inflammatory responses.

IL-17A and IL-17F stimulate chemokines via MAPK pathways (ERK1/2 and p38 but not JNK) in mouse cultured mesangial cells: synergy with TNF-α and IL-1β

We investigated the role of IL-17 family members IL-17A and IL-17F in the induction of chemokines in mouse cultured mesangial cells (SV40 MES 13 cells). We evaluated the expression of the chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) by ELISA and real-time RT-PCR (Q-PCR). Activation of MAPK was assessed by immunoblotting. IL-17RA and IL-17RC were inhibited by small interfering RNA (siRNA). We found that IL-17A or IL-17F stimulation of mesangial cells led to both a dose- and time-dependent increase in MCP-1 and MIP-2 release. This effect was dependent on mRNA transcription and protein translation. Both also enhanced TNF-alpha- and IL-1beta-mediated MCP-1 and MIP-2 release in the cells. Additionally, we observed that IL-17A and IL-17F induced MAPK (p38 MAPK, ERK1/2, and JNK) activation and that pharmacological inhibitors of p38 MAPK (SB203580) and ERK1/2 (U0126), but not JNK (SP600125), blocked the IL-17A/IL-17F-mediated MCP-1 and MIP-2 release. Mesangial cells expressed IL-17RA and IL-17RC, and the IL-17A-mediated MCP-1 and MIP-2 release was significantly blocked by soluble IL-17RA. Furthermore, inhibition of either IL-17RA or IL-17RC expression via siRNA led to significant reduction of IL-17A/IL-17F-stimulated chemokine production. We conclude that IL-17A and IL-17F induce the production of chemokines MCP-1 and MIP-2 via MAPK pathways (p38 MAPK and ERK1/2), as well as mRNA transcription and protein translation and have synergistic effects with TNF-alpha and IL-1beta in cultured mesangial cells.

Relationship of circulating tumor cells to the effectiveness of cytotoxic chemotherapy in patients with metastatic non-small-cell lung cancer.

The aim of this study was to investigate the relationship of the number of circulating tumor cells (CTCs) with the effectiveness of cytotoxic chemotherapy in patients with metastatic non-small-cell lung cancer (NSCLC). We prospectively evaluated CTCs in the peripheral blood of patients with previously untreated metastatic NSCLC. From May 2008 through August 2010, 33 patients (23 men and 10 women; median age, 64 years; range, 46-74 years) were enrolled. All patients received combination chemotherapy with gemcitabine and carboplatin. The CTCs were captured from samples of peripheral blood with a semiautomated system using an antibody against epithelial cell adhesion molecule. Blood samples with one or more CTC per 7.5 ml were defined as positive. Of total 33 patients, 12 (36.4%) had positive CTCs and 5 (15.2%) had five or more CTCs before chemotherapy. There were no differences in response rates to cytotoxic chemotherapy between CTC-positive patients and CTC-negative patients. On the other hand, the rate of progressive disease in cytotoxic chemotherapy was significantly higher in CTC-positive patients (66.7%) than in CTC-negative patients (23.8%, p = 0.02). In conclusion, the number of CTCs could be a useful predictive factor for the effectiveness of cytotoxic chemotherapy in patients with metastatic NSCLC.

Preventive and therapeutic effects of imatinib in Wistar-Kyoto rats with anti-glomerular basement membrane glomerulonephritis

Imatinib is a selective tyrosine kinase inhibitor that can block activity of the platelet-derived growth factor receptor (PDGFR) and that has immunomodulatory effects on various cell types. Here we measured the protective effects of imatinib in Wistar-Kyoto rats with nephrotoxic serum nephritis, a kidney disease model where CD8+ T cells and macrophages play pathogenetic roles. Groups of animals were given imatinib from one day before up to 13 days following induction of nephritis and from day 7 to 20 following disease induction. Compared to control rats, at each time point imatinib treatment caused significantly less proteinuria, lowered serum blood urea nitrogen and creatinine, and decreased the number of glomeruli with necrosis, crescents, and fibrin deposits. Imatinib-treated rats had a significant reduction in glomerular macrophage accumulation and reduced renal cortical PDGFR-beta and M-CSF receptor mRNA expression. Using colocalization we found that glomerular macrophages had reduced IL-1beta and MCP-1 protein expression. Late imatinib treatment significantly reduced proteinuria, serum blood urea nitrogen, and creatinine, and reversed renal histopathological changes. We show that imatinib has renoprotective and therapeutic properties and provide pre-clinical work that will need to be confirmed in patients with crescentic glomerulonephritis.

Are levels of pro-gastrin-releasing peptide or neuron-specific enolase at relapse prognostic factors after relapse in patients with small-cell lung cancer?

The purposes of this study were to assess the relationship of serum levels of pro-gastrin-releasing protein (ProGRP) and neuron-specific enolase (NSE) at relapse with survival after relapse and the response to salvage therapy and to assess whether serum levels of ProGRP and NSE at relapse are useful markers for detecting relapse earlier than are symptoms or radiographic findings in patients with small-cell lung cancer (SCLC). The subjects of this study were 103 patients with SCLC who had achieved a complete response (CR) or partial response (PR) to first-line chemotherapy. We retrospectively evaluated whether ProGRP or NSE increased earlier than symptoms or radiographic findings appeared, and the association between response to salvage therapy and levels of ProGRP or NSE at relapse. In addition, we evaluated the association between survival after relapse and clinical and demographic factors at relapse, including age, sex, response to first-line treatment, sensitivity to first-line treatment, stage, performance status (PS), and serum levels of ProGRP, NSE, and lactate dehydrogenase. At relapse, 69.3% of patients had elevated serum levels of ProGRP, 60.2% had elevated serum levels of NSE, and 81.3% had elevated serum levels of either ProGRP or NSE. However, almost all asymptomatic relapses were detected with radiographic studies. The rate of CR to salvage chemotherapy was significantly lower in patients with elevated levels of NSE (2.2%) than in patients without (26.7%; p=0.001). Univariate analysis showed that sensitivity to first-line treatment, serum levels of NSE, stage, and PS at relapse were prognostic factors for survival after relapse. Multivariate analysis showed that sensitivity to first-line treatment, serum levels of NSE, and PS at relapse were independent prognostic factors after relapse. In conclusion, serum levels of ProGRP and NSE at relapse are not useful markers for detecting relapse earlier than are symptoms or radiographic findings. On the other hand, the serum level of NSE at relapse is a useful predictive marker for CR to salvage chemotherapy and a useful prognostic factor after relapse in patients with SCLC who have achieved a CR or PR to first-line chemotherapy.

Specific epidermal growth factor receptor autophosphorylation sites promote mouse colon epithelial cell chemotaxis and restitution

Upon ligand binding, epidermal growth factor (EGF) receptor (R) autophosphorylates on COOH-terminal tyrosines, generating docking sites for signaling partners that stimulate proliferation, restitution, and chemotaxis. Specificity for individual EGFR tyrosines in cellular responses has been hypothesized but not well documented. Here we tested the requirement for particular tyrosines, and associated downstream pathways, in mouse colon epithelial cell chemotactic migration. We compared these requirements to those for the phenotypically distinct restitution (wound healing) migration. Wild-type, Y992/1173F, Y1045F, Y1068F, and Y1086F EGFR constructs were expressed in EGFR(-/-) cells; EGF-induced chemotaxis or restitution were determined by Boyden chamber or modified scratch wound assay, respectively. Pharmacological inhibitors of p38, phospholipase C (PLC), Src, MEK, JNK/SAPK, phosphatidylinositol 3-kinase (PI 3-kinase), and protein kinase C (PKC) were used to block EGF-stimulated signaling. Pathway activation was determined by immunoblot analysis. Unlike wild-type EGFR, Y992/1173F and Y1086F EGFR did not stimulate colon epithelial cell chemotaxis toward EGF; Y1045F and Y1068F EGFR partially stimulated chemotaxis. Only wild-type EGFR promoted colonocyte restitution. Inhibition of p38, PLC, and Src, or Grb2 knockdown, blocked chemotaxis; JNK, PI 3-kinase, and PKC inhibitors or c-Cbl knockdown blocked restitution but not chemotaxis. All four EGFR mutants stimulated downstream signaling in response to EGF, but Y992/1173F EGFR was partially defective in PLCγ activation whereas both Y1068F and Y1086F EGFR failed to activate Src. We conclude that specific EGFR tyrosines play key roles in determining cellular responses to ligand. Chemotaxis and restitution, which have different migration phenotypes and physiological consequences, have overlapping but not identical EGFR signaling requirements.

Patient satisfaction with sedation for flexible bronchoscopy

Background and objective:  Patient satisfaction with health care has increasingly been recognized as an important health outcome, but few studies have examined patient satisfaction with flexible bronchoscopy (FB). The purpose of this study was to assess patient satisfaction with FB conducted under conscious sedation and to identify the aspects of the procedure related to patient satisfaction.

Patient willingness to undergo chemotherapy and thoracic radiotherapy for locally advanced non-small cell lung cancer

Objectives: To determine how Japanese patients with lung cancer weigh the chance of cure and potential survival against the potential toxicity of different treatment strategies for locally advanced non‐small cell lung cancer (NSCLC).

Phase I study of the combination of gemcitabine and nedaplatin for treatment of previously untreated advanced non-small cell lung cancer

This trial was conducted to determine the maximum-tolerated dose (MTD), principal toxicity, and recommend dose for phase II study of the combination of gemcitabine and nedaplatin in patients with advanced non-small cell lung cancer (NSCLC). Patients with previously untreated NSCLC were eligible if they had a performance status of 0-2, were 75 years or younger, and had adequate organ function. The doses of gemcitabine (days 1, 8) and nedaplatin (day 1) studied were 800/60, 800/70, 800/80, 1000/80, and 1000/100 (mg/m(2)), repeated every 3 weeks. Toxicity could be assessed in all 21 patients enrolled, response could be assessed in 20 patients. The patients were 12 men and 9 women with a mean age of 69 years (range, 47-75 years). Four patients had stage IIIB disease and 17 patients had stage IV disease. The most common histologic type was adenocarcinoma. The MTD was not reached even at the highest doses. The most frequent toxic effects were thrombocytopenia and neutropenia: grade 3 or 4 thrombocytopenia was observed in 19% of patients, and grade 3 or 4 neutropenia in 24% of patients. Nonhematologic toxicities were mild. Grade 3 hepatic dysfunction occurred in 3 patients. Relatively few patients required dose modifications. The median dose-intensities were 91.5 and 93.1%, respectively, of the planned doses of gemcitabine and nedaplatin. The overall response rate was 35% (95% confidence interval, 15.4-59.2%). All responses were seen above level 3. The MTD was not reached even at the highest combination doses. We recommend doses of 1000 mg/m(2) of gemcitabine and 100 mg/m(2) of nedaplatin for phase II study. This combination chemotherapy is active and well tolerated and warrants phase II study.

The UGT1A1*28 genotype and the toxicity of low-dose irinotecan in patients with advanced lung cancer.

The association between the UGT1A1*28 genotype and the severe toxicity of low-dose irinotecan has been controversial, and few studies have examined this association in patients with lung cancer. The aim of this study was to assess the association between the UGT1A1*28 genotype and the severe toxicity of low-dose irinotecan in Japanese patients with lung cancer. From December 2005 through July 2008, 53 Japanese patients with advanced lung cancer who underwent chemotherapy that included low-dose irinotecan (50 or 60 mg/m2) as a single agent or in combination chemotherapy were retrospectively analyzed. Genomic DNA was extracted from peripheral blood. Genotypes for the UGT1A1*28 were denoted as wild-type for 6/6, heterozygous for 6/7, or homozygous for 7/7 depending on the number of TA repeats found in each allele. Of the 53 patients, 42 (79.2%) were wild-type, 9 (17.0%) were heterozygous, and 2 (3.7%) were homozygous for the UGT1A1*28 genotype. The UGT1A1*28 genotype was not associated with grade 3 or 4 neutropenia, thrombocytopia, diarrhea, or febrile neutropenia. The frequency of dose reduction of irinotecan did not differ between wild-type and heterozygous or homozygous for the UGT1A1*28 genotype. In addition, there were no significant differences in response rates and survival between wild-type and heterozygous or homozygous for the UGT1A1*28 genotype. In conclusion, the UGT1A1*28 genotype did not predict the severe toxicity of low-dose irinotecan in patients with lung cancer. Therefore, low-dose irinotecan could be administered without reducing starting dose in patients with UGT1A1*28 genotype.