Masayuki Matsumura

Functional Analysis of PIK3CA Gene Mutations in Human Colorectal Cancer

Mutations in the PIK3CA gene, which encodes the p110alpha catalytic subunit of phosphatidylinositol 3-kinase (PI3K), have been reported in human cancers, including colorectal cancer. Most of the mutations cluster at hotspots within the helical and kinase domains. Whereas H1047R, one of the hotspot mutants, is reported to have elevated lipid kinase activity, the functional consequences of other mutations have not been examined. In this study, we examined the effects of colon cancer-associated PIK3CA mutations on the lipid kinase activity in vitro, activation of the downstream targets Akt and p70S6K in vivo and NIH 3T3-transforming ability. Of eight mutations examined, all showed increased lipid kinase activity compared with wild-type p110alpha. All the mutants strongly activated Akt and p70S6K compared with wild-type p110alpha as determined by immunoblotting using phospho-specific antibodies. These mutants also induced morphologic changes, loss of contact inhibition, and anchorage-independent growth of NIH 3T3 cells. The hotspot mutations examined in this study, E542K, E545K, and H1047R, all had high enzymatic and transforming activities. These results show that almost all the colon cancer-associated PIK3CA mutations are functionally active so that they are likely to be involved in carcinogenesis.

Ulinastatin for pancreatitis after endoscopic retrograde cholangiopancreatography: A randomized, controlled trial

BACKGROUND & AIMSnPancreatitis remains the major complication of endoscopic retrograde cholangiopancreatography (ERCP), and hyperenzymemia after ERCP is common. Because ulinastatin, a protease inhibitor, has proved effective in the treatment of acute pancreatitis, the aim of this study was to assess the efficacy of ulinastatin for the prevention of post-ERCP pancreatitis and hyperenzymemia.nnnMETHODSnIn a multicenter, randomized, double-blind, placebo-controlled trial, patients undergoing a first ERCP were randomized to receive ulinastatin (150,000 U) or placebo by intravenous infusion for 10 minutes starting immediately before ERCP. All patients were hospitalized at least 24 hours after ERCP for evaluation of clinical symptoms. Serum pancreatic enzyme levels were measured before and at 4 and 18 hours after ERCP. The primary end point was the incidence of post-ERCP pancreatitis and the secondary objective was the occurrence of hyperenzymemia.nnnRESULTSnA total of 406 patients were enrolled (204 in the ulinastatin group and 202 in the placebo group). There were no differences between the 2 groups regarding baseline characteristics, details of fluoroscopic findings, or endoscopic procedure. The incidence of hyperenzymemia was significantly lower in the ulinastatin group than in the placebo group (amylase, P = .011; lipase, P = .008). Six patients in the ulinastatin group and 15 patients in the placebo group developed pancreatitis (2.9% vs. 7.4%, P = .041). There was no case of severe pancreatitis in either group. Patients who received ulinastatin did not present any side effects related to the medication.nnnCONCLUSIONSnProphylactic short-term administration of ulinastatin decreases the incidence of pancreatitis and hyperenzymemia after ERCP.

Different Effects of Point Mutations within the B-Raf Glycine-Rich Loop in Colorectal Tumors on Mitogen-Activated Protein/Extracellular Signal-Regulated Kinase Kinase/Extracellular Signal-Regulated Kinase and Nuclear Factor κB Pathway and Cellular Transformation

Recently, mutations in the B-Raf gene have been identified in a variety of human cancers, such as melanoma and colorectal carcinoma, and more than 80% of the B-Raf mutations have been V599E. Although other mutations have been reported, their functional consequences are poorly understood. In our earlier study, we demonstrated that colon tumor-associated B-Raf mutations within the kinase activation segment are not necessarily associated with an increase in mitogen-activated protein/extracellular signal-regulated kinase kinase/extracellular signal-regulated kinase (MEK/Erk) or nuclear factor κB (NFκB) signaling activity or in NIH3T3-transforming ability [T. Ikenoue et al., Cancer Res., 63: 8132–8137, 2003]. In this study, we examined the effect of colon tumor-associated mutations within the B-Raf glycine-rich loop (G loop) on MEK/Erk and NFκB signaling and on the transformation of NIH3T3 fibroblasts or IEC-6 intestinal epithelial cells. Of the six G loop mutations examined, only the B-Raf G468A significantly increased MEK/Erk and NFκB signaling and NIH3T3 transformation. Only this mutation induced transformed phenotypes of IEC-6 cells. In contrast, the B-Raf G468E mutation significantly decreased MEK/Erk signaling and NIH3T3 transformation and had no effect on NFκB signaling. The B-Raf F467C mutation moderately elevated MEK/Erk signaling and NIH3T3 transformation. The other three B-Raf mutations, R461I, I462S, and G463E, did not increase MEK/Erk or NFκB signaling or NIH3T3 transformation. Except for F467C, none of the tumors with B-Raf mutations examined in this study had K-Ras mutations. These results suggest that some of the B-Raf G loop mutations reported in colorectal tumors do not increase kinase or transforming activities but might contribute to carcinogenesis via other mechanisms or be irrelevant to carcinogenesis.

Rapid Detection of Mutations in the 23S rRNA Gene of Helicobacter pylori That Confers Resistance to Clarithromycin Treatment to the Bacterium

ABSTRACT We developed a new method capable of detecting point mutations in the 23S rRNA gene of Helicobacter pylori using a LightCycler. Our method can detect a mutation in this gene in less than 1 h and can process many samples at once, thereby contributing to the selection of patients suitable for clarithromycin-based therapy.

Quantitation of α‐fetoprotein and albumin messenger RNA in human hepatocellular carcinoma

To analyze gene expression of α‐fetoprotein (AFP) and albumin in hepatocellular carcinoma (HCC), messenger RNAs (mRNAs) of these proteins in six human hepatoma cell lines and in 30 cases of HCC were quantitatively analyzed by competitive reverse transcription (RT) followed by polymerase chain reaction (PCR). The transcriptional levels of both AFP and albumin genes in HepG2 and Huh 7 cell lines were 1010 copies/μg RNA, in contrast to approximately 105 copies/μg RNA in HLE and HLF cell lines. AFP and albumin mRNA levels in three normal livers were 105 and 1010 transcripts/μg RNA, respectively. In 30 cases with HCC AFP mRNA level in neoplasm was 10 to 105‐fold enhanced as compared with that of nonneoplastic portion, and correlated with serum AFP level and tumor size (P < .01). In contrast, albumin mRNA level was not reduced in the neoplasms presenting enhanced AFP mRNA levels, indicating that AFP and albumin gene expression in situ is not necessarily mutually exclusive. Prospective analysis revealed that an increased serum AFP was shown at the time of recurrence among patients with enhanced AFP mRNA levels in neoplasm only, indicating that AFP mRNA levels in neoplasm could be a clinically predictable tool.

Direct detection of Mycobacterium tuberculosis using polymerase chain reaction assay among patients with hepatic granuloma

BACKGROUNDnIn liver tuberculosis, demonstration of acid bacilli by conventional methods remains futile. Since the definitive diagnosis of liver tuberculosis is based on the histologic evidence of granulomatous process with caseation necrosis, seen in only a third of cases, the diagnosis is made retrospectively by response to empirical anti-tuberculous drug therapy.nnnAIMSnOur objective is to establish a polymerase chain reaction assay for detection of Mycobacterium tuberculosis affecting the liver using the paraffin-embedded liver biopsy specimens obtained from patients with hepatic granulomas.nnnMETHODSnAs positive control, patients having either definitive (n=8) or presumptive (n=9) tuberculosis on the basis of clinical, microbiological, histologic data and their positive response to empirical treatment of anti-tuberculous drugs were used. Patients with hepatic granulomas secondary to schistosomiasis (n=6), sarcoidosis (n=2) and other liver diseases (n=10) were used as negative control.nnnRESULTSnOf those patients who were diagnosed as having definitive and presumptive liver tuberculosis, positivity by one-step polymerase chain reaction was 100% and 44%, respectively. Using the nested polymerase chain reaction, positivity increased to 78% with presumptive liver tuberculosis. In contrast, the polymerase chain reaction assays were negative among all patients with hepatic granuloma due to non-tuberculous-in-origin and other liver diseases.nnnCONCLUSIONSnThe overall positivity of this polymerase chain reaction assay (88%) compares favorably with that of other conventional methods (12%). Thus, this polymerase chain reaction assay may be a reliable diagnostic tool for liver tuberculosis in a patient population in which the prevalence of diseases associated with hepatic granuloma is common.

Presence of α-fetoprotein mRNA in blood correlates with outcome in patients with hepatocellular carcinoma

Abstract Background/Aims: Since hematogenous spread of tumor cells may adversely affect the prognosis of patients with hepatocellular carcinoma, we prospectively analyzed whether the presence of alpha-fetoprotein (AFP) messenger RNA (mRNA) in blood, used as a marker of circulating hepatocellular carcinoma cells, correlates with outcome. Methods: Eighty-eight patients were enrolled between December 1993 and August 1995, and 81 were followed until the end of 1997. All patients were treated with percutaneous ethanol injection therapy and/or transarterial embolization during follow-up. The status of AFP mRNA in blood was serially determined. Cumulative metastasis-free survival and overall survival were analyzed in relation to AFP mRNA and other clinical and laboratory variables. Results: Among 81 patients followed, 54 were positive for AFP mRNA at entry and 27 were negative. Extrahepatic metastasis developed more frequently among the AFP mRNA-positive patients (13 of 54) than among the AFP mRNA-negative patients (2 of 27) ( p =0.0296). After treatment, AFP mRNA became negative in 24 of 54 patients (44%). Cumulative metastasis-free survival and overall survival were significantly better in the 24 patients whose AFP mRNA became negative after treatment than in the 30 patients with persistently positive AFP mRNA ( p =0.0001 and p Conclusions: The presence or absence of AFP mRNA in blood is a predictor of outcome in patients with hepatocellular carcinoma.

Analysis of the β-Catenin/T Cell Factor Signaling Pathway in 36 Gastrointestinal and Liver Cancer Cells

We investigated the frequency and mechanism of |bT‐catenin/T cell factor (Tcf) signaling activation in a panel of 36 human gastrointestinal and liver cancer cell lines. Reporter assay and electrophoretic mobility shift assay revealed that the β‐catenin/Tcf signaling was upregulated in 12 of 12 (100%) colorectal, 5 of 8 (68%) gastric, 2 of 7 (29%) hepatic, and none of 9 pancreatic cancer cell lines. The activation of the pathway was mainly due to the mutation of adenomatous polyposis coli (APC) or β‐catenin, and Tcf‐4 was highly expressed in these cell lines with upregulated signaling. Nuclear β‐catenin was observed not only in the signaling‐activated cell lines, but also in 14 of 25 (56%) primary gastric cancers, 15 of 20 (75%) colon cancers, 5 of 19 (26%) hepatocellular carcinomas, and none of 13 pancreatic cancers. The presence of signaling‐upregulated gastric cancer cell lines with intact APC and β‐catenin suggests the involvement of other mechanisms than mutations of APC or β‐catenin.

Hepatocyte Nitric Oxide Production Is Induced by Kupffer Cells

To investigate the cellular communication in theliver, nitric oxide (NO) production by sinusoidal cellsand hepatocytes by stimulation with cytokines andKupffer cell-conditioned medium was quantitatively analyzed. NO production by the cells wasmeasured by the Griess reaction, and nitric oxidesynthase (iNOS) transcription level by a competitiveRT-PCR assay using mutant iNOS mRNA as a standard. NOproduction and iNOS mRNA transcriptional levels in Kupffercells were markedly increased by stimulation withlipopolysaccharide (LPS) and interferon-γ(IFN-γ), and moderately by interleukin-1β(IL-1β). NO production by hepatocytes was notsignificantly enhanced by LPS, but was markedly enhancedby IL-1β or the combination of tumor-necrosisfactor-α (TNF-α) and IFN-γ. HepatocyteNO production and iNOS mRNA levels were markedly enhanced bythe LPS-activated Kupffer cell conditioned medium, butthese effects were reduced by heat treatment or anti-TNFantibody. Although NG-monomethyl-L-arginine acetate and dexamethasone reduced NO productionby the cells, the iNOS mRNA level was reduced bydexamethasone only. Gel-shift assay showed NF-κBactivation in hepatocytes during this activation. These data reinforce the importance of cellularcommunication between sinusoidal cells andhepatocytes.

A case of primary gastric choriocarcinoma and a review of the Japanese literature

A 63-year old woman who had experienced melena for 2 weeks was admitted to Tokyo University Hospital. Gastric adenocarcinoma was diagnosed endoscopically and histologically, and a total gastrectomy was performed soon thereafter. Pathological examination of the resected stomach revealed choriocarcinoma of the stomach. Although chemotherapy was administered after surgery, she died 3 months after admission. Autopsy confirmed the diagnosis of primary gastric choriocarcinoma, a rare, but highly malignant tumor. It is characteristic; macroscopically it forms a necrotic mass with bleeding, and microscopically it often consists of adenocarcinoma and choriocarcinoma. Since its prognosis is extremely poor, we must take into account the possibility of primary gastric choriocarcinoma when a hemorrhagic gastric tumor with necrosis is found.