Takatoshi Ishiko

p73 is regulated by tyrosine kinase c-Abl in the apoptotic response to DNA damage

The protein p73 is a structural and functional homologue of the p53 tumour-suppressor protein but, unlike p53, it is not induced in response to DNA damage,. The tyrosine kinase c-Abl is activated by certain DNA-damaging agents and contributes tothe induction of programmed cell death (apoptosis) by p53-dependent and p53-independent mechanisms. Here we show that c-Abl binds to p73 in cells, interacting through its SH3 domain with the carboxy-terminal homo-oligomerization domain of p73. c-Abl phosphorylates p73 on a tyrosine residue at position 99 both in vitro and in cells that have been exposed to ionizing radiation. Our results show that c-Abl stimulates p73-mediated transactivation and apoptosis. This regulation of p73 by c-Abl in response to DNA damage is also demonstrated by a failure of ionizing-radiation-induced apoptosis after disruption of the c-Abl–p73 interaction. These findings show that p73 is regulated by a c-Abl-dependent mechanism and that p73 participates in the apoptotic response to DNA damage.

Glypican-3, overexpressed specifically in human hepatocellular carcinoma, is a novel tumor marker

With the global pandemic of hepatitis B and C infections, the incidence of Hepatocellular carcinoma (HCC) is rapidly increasing world wide. We identified glypican-3 (GPC3), a novel oncofetal gene over-expressed specifically in human HCC, as based on data of cDNA microarrays. As GPC3 is a GPI-anchored membrane protein and could be secreted, we attempted to detect secreted GPC3 protein in sera from HCC patients using Western blotting and ELISA. GPC3 protein was positive in sera of 40.0% (16/40) of HCC patients, and negative in sera from subjects with liver cirrhosis (LC) (0/13), chronic hepatitis (CH) (0/34), and healthy donors (0/60). All subjects were Japanese. Although 12 of 40 HCC patients were negative for both alpha-fetoprotein (AFP) and PIVKA-II well known tumor markers of HCC, four of these were GPC3-positive in the sera. We also observed vanishing GPC3 protein in the sera of three patients after the surgical treatment for HCC. On the other hand, immunohistochemical analysis revealed that HCC expressed GPC3 protein in all 14 HCC patients tested. In conclusion, GPC3, as defined in this study was shown to be a useful tumor marker for cancer-diagnosis for large numbers of patients with HCC.

Elevation of circulating interleukin 6 after surgery: Factors influencing the serum level

To investigate the effect of surgical trauma and other factors on the postoperative elevation of serum interleukin 6 (IL-6), we examined changes in IL-6 concentration after major thoracoabdominal surgery. Serum IL-6 levels reached the maximum concentration on the first postoperative day in all 38 patients, with peak ranging from 1400.8 +/- 383.4 pg/ml (mean +/- SEM) to 29.8 +/- 3.8 among six groups who underwent surgery at different sites. The IL-6 peak was significantly correlated with surgical trauma as defined by the operation length and the volume of blood loss during surgery (r = 0.554, P < 0.01 and r = 0.427, P < 0.01, respectively). The peak concentration of serum IL-6 in patients undergoing esophagectomy was significantly higher than in those undergoing pancreaticoduodenectomy (P < 0.05), despite a similar degree of surgical trauma defined by the operation length and volume of blood loss during surgery. Peak IL-6 concentration observed in a patient who underwent esophagectomy was about 100-fold greater in fluid drained from the thorax than in the peripheral blood. IL-6 mRNA was demonstrated in leukocytes from thoracic and abdominal exudate at 6, 24 and 48 h after surgery. In contrast, IL-6 mRNA could not be detected in leukocytes from the peripheral blood. Similar findings were also observed for interleukin 8 (IL-8). However, interleukin 1 beta (IL-1 beta) and tumour necrosis factor-alpha (TNF-alpha) were detected only once after surgery in the drainage fluid.(ABSTRACT TRUNCATED AT 250 WORDS)

Curcumin Inhibits Interleukin 8 Production and Enhances Interleukin 8 Receptor Expression on the Cell Surface Impact on Human Pancreatic Carcinoma Cell Growth by Autocrine Regulation

Curcumin, the yellow pigment in turmeric, has been shown to prevent tumor progression in a variety of tissues in rodents. The authors investigated the effect of curcumin on human carcinoma cell lines to determine whether constitutive interleukin‐8 (IL‐8) production of tumor cells was correlated with nuclear factor κB (NF‐κB) activation and cell growth activity.

Non-Occlusive Mesenteric Ischemia and Its Associated Intestinal Gangrene in Acute Pancreatitis

Background/Aims: Non-occlusive mesenteric ischemia (NOMI) has been defined as diffuse intestinal ischemia that often results in intestinal gangrene in the presence of a patent arterial trunk. The prevalence and nature of NOMI in acute pancreatitis was investigated. Methods: A total of 120 consecutive patients with acute pancreatitis managed in the Department of Surgery II, Kumamoto University Medical School, from April 1992 through December 2002, were investigated retrospectively. Among them, 60 patients had the severe form. Results: The overall mortality of acute pancreatitis patients was 8.3% (10/120). The prevalence and mortality of acute pancreatitis associated with NOMI were 6.7% (8/120) and 63% (5/8), respectively, while those of patients with NOMI-associated intestinal gangrene were 4.2% (5/120) and 100% (5/5), respectively. The mortality of patients with severe acute pancreatitis who did not develop NOMI was 10% (5/52). All patients with NOMI-associated intestinal gangrene quickly progressed and subsequently died of multiple organ failure. Plasma creatine phosphokinase (CPK) and lactate levels were elevated significantly in patients with NOMI. Conclusion: Acute pancreatitis associated with NOMI was extremely severe. If the plasma CPK and lactate levels are extremely high, NOMI should be suspected.

Identification of CXCL5/ENA‐78 as a factor involved in the interaction between cholangiocarcinoma cells and cancer‐associated fibroblasts

Knowledge of tumor‐stromal interactions is essential for understanding tumor development. We focused on the interaction between cholangiocarcinoma and cancer‐associated fibroblasts (CAFs) in intrahepatic cholangiocarcinoma and reported their positive interaction in vitro and in vivo. The aim of this study is to identify the key protein involved in the interaction between cholangiocarcinoma cells and CAFs and its role on cholangiocarcinoma progression. Using the conditioning medium from cholangiocarcinoma cells, hepatic stellate cells and coculture of them, Protein‐Chip analysis with SELDI–TOF–MS showed that the peak of an 8,360‐Da protein remarkably increased in the coculture medium. This protein was identified as CXCL5/ENA78, epithelial cell‐derived neutrophil‐activating peptide‐78, by q‐TOF/MS/MS analysis. Two cholangiocarcinoma cell lines, HuCCT1 and RBE, produced CXCL5 that promoted their invasion and migration in an autocrine fashion. These effects of CXCL5 significantly decreased by inhibition of CXC‐receptor 2, which is the receptor for CXCL5. In addition, IL‐1β produced by hepatic stellate cells induced the expression of CXCL5 in cholangiocarcinoma cells. In human tissue samples, a significant correlation was observed between CAFs and CXCL5 produced by cholangiocarcinoma cells in intrahepatic cholangiocarcinoma (p = 0.0044). Furthermore, the high‐CXCL5‐expression group exhibited poor overall survival after curative hepatic resection (p = 0.027). The presence of tumor‐infiltrating neutrophils expressing CD66b was associated with CXCL5 expression in tumor cells (p < 0.0001). These data suggest that CXCL5 is important for the interaction between cholangiocarcinoma and CAFs, and inhibition of tumor‐stromal interactions may be a useful therapeutic approach for cholangiocarcinoma.

Pro-apoptotic effect of the c-Abl tyrosine kinase in the cellular response to 1-β- D -arabinofuranosylcytosine

Treatment of cells with the antimetabolite 1-β-D-arabinofuranosylcytosine (ara-C) and other genotoxic agents is associated with activation of the c-Abl protein tyrosine kinase. The functional role of c-Abl in the response to DNA damage, however, remains unclear. The present studies demonstrate that cells expressing a dominant negative, kinase-inactive c-Abl (K-R) are resistant to killing by ara-C. The expression of c-Abl (K-R) blocked ara-C-induced apoptosis by a mechanism that is at least in part independent of the p53 tumor suppressor. Cells null for c-Abl also exhibited resistance to induction of apoptosis. These findings provide support for a pro-apoptotic function of c-Abl in the response to certain genotoxic drugs.

Visualization of the heterogeneous internal structure of so-called "pancreatic necrosis" by magnetic resonance imaging in acute necrotizing pancreatitis.

Introduction Contrast-enhanced computed tomography (CT) is the gold standard for assessing the severity of acute pancreatitis, especially for evaluating the presence of pancreatic necrosis (poorly perfused area). However, the contrast medium used for CT is potentially toxic to the pancreas and kidney. Therefore, medical institutions without facilities for hemodialysis hesitate to acquire contrast-enhanced CT images. Diagnostic values of magnetic resonance imaging (MRI) in pancreatic diseases have been shown. Aim To evaluate the usefulness of MRI in the assessment of the severity of acute pancreatitis. Results All necrotic regions in the pancreas were visualized by gadolinium-enhanced MRI. Furthermore, MRI can discriminate the poorly perfused pancreatic area, namely so-called “pancreatic necrosis” judged on CT, into three parts: 1) necrotic area of the pancreatic parenchyma, 2) perinecrotic fluid collection, and 3) hemorrhagic foci. Inflammatory changes that were required for severity grading were also evaluated sufficiently by MRI. Conclusion These results suggest that MRI is useful for the assessment of severity of acute pancreatitis.

Comparison between hepatic resection and radiofrequency ablation as first-line treatment for solitary small-sized hepatocellular carcinoma of 3 cm or less.

It is a matter of debate whether hepatic resection (HR) or radiofrequency ablation (RFA) should be preferred for the treatment of patients with hepatocellular carcinoma (HCC). The aim of this study is to compare the long‐term outcome between HR and RFA in patients with solitary small‐sized HCC.

Predictive factors for platelet increase after partial splenic embolization in liver cirrhosis patients

Background and Aim:  Partial splenic embolization (PSE) is often performed for improving thrombocytopenia in cirrhotic patients. We investigated the largely unclear predictive factors for platelet increase at both 1 month and 1 year after PSE.