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Masaaki Oka

Publications and source records attributed to Masaaki Oka.

At least 19 recordsLinked to original sources
PubMed2006

Involvement of c-myc-regulated genes in hepatocellular carcinoma related to genotype-C hepatitis B virus.

PURPOSE: The purpose of this study was to elucidate the molecular basis of hepatocellular carcinoma (HCC) caused by genotype-C hepatitis B virus (HBV). METHODS: We compared molecular profiles of 15 HCCs and five non-tumorous livers, all of which were associated with genotype-C HBV infection, using DNA microarray technology. RESULTS: Our supervised learning identified 237 genes whose expression differed between HCCs and non-tumorous livers. This result was validated by a false discovery rate of 0%. Levels of expression of 35 and 202 genes were higher and lower, respectively, in HCCs than in non-tumorous livers. Among the 237 genes, we highlighted the top 35 upregulated and top 35 down regulated genes in tumor. Interestingly, when overlapping genes were excluded, 12 (e.g., NM23-H2, MCM7, PARP1, YWHAH, HSPB1, and MSH2) of the top 34 upregulated genes and five (e.g., MT1A and MT3) of the top 33 downregulated genes were c-myc-regulated genes. The microarray data for five randomly selected genes (MCM7, UBE2L3, PPIA, CXCL12, and ASS) were confirmed by quantitative real-time reverse transcription-polymerase chain reaction. CONCLUSIONS: Our results indicate that many c-myc-regulated genes are involved in genotype-C-HBV-related HCC, suggesting that c-myc is related to the hepatocarcinogenic activity of genotype-C HBV.

Carcinoma, Hepatocellular↗
PubMed2006

Increased expression and phosphorylation of liver glutamine synthetase in well-differentiated hepatocellular carcinoma tissues from patients infected with hepatitis C virus.

Hepatocellular carcinoma (HCC) is one of the most common fatal cancers, and chronic infection with hepatitis C virus (HCV) is thought to be one of the main causes in Japan. To identify diagnostic or therapeutic biomarkers for HCC associated with HCV (HCV-HCC), we tried to elucidate the factors related to the products from cancerous tissues of HCV-infected patients. From proteomic differential display analysis of liver tissue samples from HCV-HCC cancerous tissues and corresponding non-cancerous tissues from patients, three protein spots of the same molecular mass (42 kDa), whose expression increased in well-differentiated cancerous tissues, were detected. Although their pI were different, they were identified as glutamine synthetase (GS) by PMF with MALDI-TOF MS and by Western blotting using anti-GS specific mAb. Immunohistochemical analysis showed that tumor tissue consists of two parts, GS-positive cell and GS-negative cell regions, suggesting that GS-producing cells grew in the tumor tissue as a nodule in nodules. The tryptic peptides of the most acidic GS isoform lost the signal of 899.5 Da, corresponding a peptide of SASIRIPR, and gained a signal of 1059.5 Da, which was submitted to PSD analysis. PSD analysis showed the neutral loss by elimination of two phosphate groups, supposed to be on serine residues of the 899.5-Da peptide, from serine 320 to arginine 327 in GS. PMF followed by PSD analysis is thought to be useful for the determination of phosphorylation sites of proteins showing molecular heterogeneity.

Amino Acid Sequence↗
PubMed2006

Proteomic analysis of autoantibodies in patients with hepatocellular carcinoma.

To detect autoantibodies that could be diagnostic markers for hepatocellular carcinoma (HCC), we analyzed serum autoantibodies comprehensively that showed immunoreactivity to proteins in tumor tissue obtained from patients with HCC. Fifteen paired samples of HCC tissue and corresponding nontumorous liver tissue as well as five normal liver tissue samples were used in the study. A combination of proteomics and SEREX (serologic analysis of recombinant cDNA expression libraries) technique was used. Tissue proteins were separated by 2-DE, transferred onto PVDF membranes, and immunoblotted with autologous sera. By comparing each immunoblot pattern, we identified four immunoreactive spots with stronger staining intensity in tumorous tissues than in corresponding nontumorous tissues and in normal liver tissues. Matched proteins on 2-DE gels were identified by LC-MS/MS. These immunoreactive proteins were heat shock 70 kDa protein 1 (HSP70), glyceraldehyde 3-phosphate dehydrogenase, peroxiredoxin, and manganese superoxide dismutase (Mn-SOD). In HCC sera, occurrences of autoantibodies against these proteins were 7/15 (46.7%), 5/15 (33.3%), 5/15 (33.3%), and 6/15 (40.0%), respectively, whereas 2/20 (10.0%), 7/20 (35.0%), 0/20 (0.0%), and 2/20 (10.0%) were in control sera. Immunoblot analysis using commercially available purified proteins was performed to confirm the specificity of autoantibodies. By statistical analysis, autoantibodies against HSP70, peroxiredoxin, and Mn-SOD showed significantly high-frequency immunoreaction in HCC sera. The three antibodies were considered patient-specific antibodies in HCC and may be candidate diagnostic biomarkers for HCC.

Adult↗
PubMed2006

CT lymphography-navigated sentinel lymph node biopsy in patients with superficial esophageal cancer.

BACKGROUND: To evaluate experimentally and clinically the feasibility of a newly developed technique of endoscopic computed tomography (CT) lymphography with endoscopic submucosal injection of iopamidol for esophageal sentinel lymph node (SLN) mapping and biopsy examination. METHODS: Nine anesthetized dogs underwent CT after endoscopic submucosal injection of 2 mL iopamidol; 1.25-mm thick CT images were obtained before and at 1, 3, 5, 7, and 10 minutes after contrast injection. Clinically, 12 patients with superficial esophageal cancer (preoperative imaging stage: cT1, cN0) underwent CT lymphography in a similar fashion at 1, 5, and 10 minutes after peritumoral injection, followed by radical esophagectomy and regional lymph node dissection under CT lymphography guidance. RESULTS: CT lymphography visualized the draining lymphatic vessels and SLNs within 5 minutes after contrast injection. All 14 SLNs in dogs (average, 1.5 nodes per animal; range, 1-2) and 28 SLNs in patients (average, 2.3 nodes per patient; range, 1-4) were found intraoperatively at the correct location under CT lymphography guidance. Lymph node metastasis could be detected with excellent sensitivity and accuracy in this small number of patients with no false-negative findings; metastasis was positive only in the preoperatively identified SLNs in 4 patients and in both SLNs and distant nodes in 1 patient, and was negative in all resected nodes in the remaining 7 patients. CONCLUSIONS: Endoscopic CT lymphography appears to allow accurate identification of direction and locations of lymph flow and SLNs, and has the potential clinical applicability for esophageal SLN mapping and biopsy examination, but will require a large study to determine its accuracy and usefulness.

Aged↗
PubMed2006

Protein level of apolipoprotein E increased in human hepatocellular carcinoma.

Many reports suggest that hepatic steatosis leads to hepatocellular carcinoma (HCC), including hepatitis C virus or non-alcoholic steatohepatitis. Proteomic study of tumor tissues from HCC patients, focusing on apolipoprotein (apo) of apoA1, apoB100 and apoE, was performed by immunoblotting. Although the significant changes of apoA1 or apoB100 could not be shown statistically, the immunoblotting showed the increase in protein level of apoE in the tumor tissues of 88% of patients without increase of apoE gene expression and serum level. These results suggest the accumulation of apoE by impaired secretion. Moreover, immunoblot analysis on two-dimensional electrophoresis showed a strong possibility that sialylated forms of apoE also were increased in tumorous tissues of HCC. ApoE level in tumorous tissues is frequently elevated and may be a good histological marker for HCC.

Adult↗
PubMed2006

Esophageal squamous cell carcinomas with distinct invasive depth show different gene expression profiles associated with lymph node metastasis.

We examined the gene expression profiles of esophageal squamous cell carcinomas (ESCCs) with respect to degree of invasive depth and lymph node (LN) involvement in a large cohort. We used high-density oligonucleotide microarrays to examine the expression of 22,115 genes in 54 ESCCs and 11 non-cancerous esophageal tissues. We found that 4,155 genes were biologically significant in both ESCC and non-cancerous esophageal tissue by analysis of Present Call (hybridization quality by Affymetrix) throughout all samples. From these genes, we used a supervised learning method to select genes responsible for the development of ESCC. We found that 999 genes were expressed differentially in pT1/pN0 tumors vs. non-cancerous esophageal tissue. In the same manner, 48, 66 and 30 genes were expressed differentially in pT1/pN0 tumors vs. pT1/pN1 tumors, pT1/pN0 tumors vs. pT2-4/pN0 tumors and pT2-4/pN0 tumors vs. pT2-4/pN1 tumors, respectively. Intriguingly, there were no overlaps between the 48 LN metastasis-related genes of pT1 tumors and the 30 LN metastasis-related genes of pT2-4 tumors, suggesting that ESCCs with distinct invasive depths express different genes linked to LN metastasis. Our present results suggest that the degree of invasive depth must be considered when predicting LN metastasis of ESCC from gene expression profiles.

Aged↗
PubMed2006

Relation between cytokine promoter gene polymorphism and toxicity of 5-fluorouracil plus cisplatin chemotherapy.

Variability in the efficacies and toxicities of anticancer agents is a major problem. We hypothesized that polymorphisms in cytokine gene promoters may underlie genetic susceptibility to chemotherapy-induced toxicities in the Japanese. DNA was extracted from 100 patients undergoing 5-fluorouracil plus cisplatin chemotherapy. We used a case-only design to evaluate the relation between toxicities and cytokine promoter gene polymorphisms. The following polymorphisms were genotyped: tumor necrosis factor (TNF)-alpha-1031T/C, interleukin (IL)-1beta-511C/T, IL-6-634C/G, IL-10-819T/C, IL-18-137G/C, macrophage migration inhibitory factor -173G/C, and 86-basepair variable numbers of tandem repeat in intron 2 of the IL-1 receptor antagonist. The frequency of the IL-6-634 GC and GG genotypes was significantly higher in patients with grades 1-4 leukopenia (P=0.003; Crude-odds ratios (Cr-OR) =4.0), neutropenia (P=0.0051; Cr-OR=3.6), or thrombocytopenia (P<0.0001; Cr-OR=6.1) than in patients without these toxicities. Similarly, the frequency of the IL-1beta-511 TC and TT genotypes and the frequency of the TNF-alpha-1031 TT genotype were significantly higher in patients with grades 1-4 thrombocytopenia (P=0.015; Cr-OR=2.9) and stomatitis (P=0.02; Cr-OR=3.1), respectively. Multivariate analysis of factors such as age, sex, disease type, purpose of the chemotherapy, use of radiotherapy, and cytokine promoter gene polymorphisms showed polymorphisms to be significant predictors of toxicity. Our results suggest that polymorphisms in cytokine gene promoters may be associated with susceptibilities to leukopenia, neutropenia, thrombocytopenia and stomatitis in patients treated with 5-fluorouracil plus cisplatin.

Adult↗
PubMed2006

Different molecular pathways determining extrahepatic and intrahepatic recurrences of hepatocellular carcinoma.

Recent genome-wide screens have identified genes associated with the metastatic potential of hepatocellular carcinoma (HCC); however, there is little overlap between the identified genes, and interpretations of the results remain controversial. These inconsistencies may be related to differences in the sample populations, use of distinct microarray platforms and algorithms, and the complicated modes of HCC recurrence. We investigated the gene expression profiles of extrahepatic recurrence (EHR) and early intrahepatic recurrence (IHR), which are two representative modes of recurrence of HCC attributable to metastasis. We used DNA microarray analysis and identified 46 signature genes for EHR in 35 HCCs in a supervised learning manner. The obtained gene expression profile was compared with that for early IHR that was determined previously in the same manner. The 46 signature genes for EHR included many cell adhesion-related genes (ITGA6, SPP1, DNMBP, CD44 and POSTN), which all showed higher expression in HCC with EHR than in HCC without EHR. The 46 signature genes for early IHR included 10 immune response-related genes, which all showed lower expression in HCC with early IHR than in HCC without early IHR. The signature genes for EHR included only two immune response-related genes (P=0.013). These results suggest that alteration of the cell adhesion system plays a central role in EHR and that reduction of the immune response is a specific step in early IHR. These results indicate that the metastatic processes in EHR and early IHR involve different molecular pathways.

Adult↗
PubMed2006

Identification of ID2 associated with invasion of hepatitis C virus-related hepatocellular carcinoma by gene expression profile.

Portal vein invasion (PVI) is a hallmark of metastatic potential of hepatocellular carcinoma (HCC) and is frequently found at a stage of moderately differentiated HCC. To identify genes involved in PVI of HCC associated with hepatitis C virus (HCV), we performed a comprehensive analysis of 12,600 genes in 35 moderately differentiated HCV-related HCCs by DNA microarray. Our supervised learning method identified 35 genes involved in PVI. Among the 35 identified genes, we focused on the inhibitor of DNA binding 2 (ID2), because it encodes a liver-rich dominant-negative helix-loop-helix protein. The microarray results for ID2 were reproduced by quantitative real-time reverse transcription (QRT)-PCR and Western blot analyses. In an independent set of HCV-related HCCs (n=28) and HCV-unrelated HCCs (n=14), our QRT-PCR showed that decrease in ID2 mRNA levels were associated with PVI in HCV-related HCC but not HCV-unrelated HCC. In conclusion, our results strongly suggest that ID2 plays an important role in PVI process of HCV-related HCC.

Carcinoma, Hepatocellular↗
PubMed2006

Molecular features linked to the growth-inhibitory effects of gemcitabine on human pancreatic cancer cells.

Although gemcitabine (GEM) is widely used in the treatment of pancreatic cancers, the molecular mechanisms that underlie its anti-tumor effects are not fully understood. To clarify the anti-tumor mechanism(s) of GEM, we studied a human pancreatic cancer cell line, YPK-1, that showed a 50% inhibitory concentration (IC50) of GEM of 6.3 x 10(-3) microg/ml after 72 h of exposure. Cell proliferation was perturbed by 6 to 72 h of exposure to GEM concentrations equal to one-half or one-quarter of the IC50. We used cDNA microarrays containing 2976 genes to identify genes with expression affected by exposure to GEM. The self-organizing map identified nine clusters, including 85 and 87 genes, that showed differential expression in response to exposure to one half and one quarter IC50 GEM, respectively. Of these, 24 genes were common to cells exposed to the two different concentrations of GEM. Most are signal transduction or transcription-related genes. The microarray data for two of these genes, SPARC and RPS8, were validated by RT-PCR. Although further studies are needed to examine whether the changes in expression profiles of these genes are specific to cells exposed to GEM, the present data provide insights into the anti-tumor effects of GEM on pancreatic cancers.

Antimetabolites, Antineoplastic↗
PubMed2006

[Adjuvant hepatic arterial infusion after resection of hepatic metastasis from colorectal cancer].

We examined retrospectively the efficacy of hepatic arterial infusion (HAI) chemotherapy comparing systemic treatment as adjuvant therapy after the curative resection of hepatic metastasis from colorectal cancer. Seventeen cases of HAI and 8 of the systemic treatment were enrolled in this study. We compared the pattern of recurrent sites and the overall survival rate between the two groups. There was no difference in a patients' background. Intrahepatic recurrence rate was lower and extrahepatic recurrence rate was higher in the HAI group, but not significant. The 1-, 3-, and 5-year overall survival rate was 94, 72, and 49% in the HAI group and 100, 100, and 50% in the systemic treatment group (p = 0.29), respectively. HAI chemotherapy did not contribute to the elongation of survival time in comparison with systemic treatment. This study indicates that there is no efficacy of HAI alone after the resection of hepatic metastasis from colorectal cancer and that there is need to use systemic chemotherapy together with HAI to prevent an extrahepatic recurrence.

Adult↗
PubMed2005

Tumor HLA-DR expression linked to early intrahepatic recurrence of hepatocellular carcinoma.

The outcome of patients with hepatocellular carcinoma (HCC) remains poor because of the high frequency of intrahepatic recurrence (IHR), particularly early IHR within 1 year of hepatectomy. To search for genes involved in early IHR, we performed DNA microarray analysis in a training set of 33 HCCs and selected 46 genes linked to early IHR from approximately 6,000 genes by means of a supervised learning method. Gene selection was validated by a false discovery rate of 0.37%. The 46 genes included many immune response-related genes, which were all downregulated in HCCs with early IHR. Four of these genes (HLA-DRA, HLA-DRB1, HLA-DG and HLA-DQA), encoding MHC class II antigens, were coordinately downregulated in HCCs with early IHR compared to levels in HCCs with nonrecurrence. A cluster analysis reproduced expression patterns of the 4 MHC class II genes in 27 blinded HCC samples. To localize the major site of production of HLA-DR protein in the tumor, we used 50 frozen specimens from 50 HCCs. Immunofluorescence staining showed that HLA-DR protein levels in tumor cells, but not in stromal cells, were associated with the transcription levels of HLA-DRA determined by both DNA microarray analysis and real-time quantitative reverse transcription-PCR. Univariate analysis showed that tumor HLA-DR protein expression, pTNM stage and venous invasion were associated with early IHR. Multivariate analysis showed that tumor HLA-DR protein expression was one of the independent risk factors for early IHR, suggesting HLA-DR protein potential as a biomarker and a molecular target for therapeutic intervention.

Aged↗
PubMed2005

Molecular dissection of a medicinal herb with anti-tumor activity by oligonucleotide microarray.

It is difficult to understand precisely the physiological actions of herbs because they contain a complex array of constituent molecules. In the present study we used DNA microarray data for 12600 genes to examine the anti-proliferative activity of the herb Coptidis rhizoma and eight constituent molecules against eight human pancreatic cancer cell lines. We identified 27 genes showing strong correlation with the 50% inhibitory dose (ID50) of C. rhizoma after 72-h exposure. Hierarchical cluster analysis with correlation coefficients between expression levels of these 27 C. rhizoma-related genes and the ID50 of each constituent molecule classified these test molecules into two clusters, one consisting of C. rhizoma and berberine and the other consisting of the remaining seven molecules. Our results suggest that one molecule, berberine, can account for the majority of the anti-proliferative activity of C. rhizoma and that DNA microarray analyses can be used to improve our understanding of the actions of an intact herb.

Antineoplastic Agents, Phytogenic↗
PubMed2005

Self-organizing-map-based molecular signature representing the development of hepatocellular carcinoma.

Using high-density oligonucleotide array, we comprehensively analyzed expression levels of 12600 genes in 50 hepatocellular carcinoma (HCC) samples with positive hepatitis C virus (HCV) serology (well (G1), moderately (G2), and poorly (G3) differentiated tumors) and 11 non-tumorous livers (L1 and L0) with and without HCV infection. We searched for discriminatory genes of transition (L0 vs. L1, L1 vs. G1, G1 vs. G2, G2 vs. G3) with a supervised learning method, and then arranged the samples by self-organizing map (SOM) with the discriminatory gene sets. The SOM arranged the five clusters on a unique sigmoidal curve in the order L0, L1, G1, G2, and G3. The sample arrangement reproduced development-related features of HCC such as p53 abnormality. Strikingly, G2 tumors without venous invasion were located closer to the G1 cluster, and most G2 tumors with venous invasion were located closer to the G3 cluster (P=0.001 by Fisher's exact test). Our present profiling data will serve as a framework to understand the relation between the development and dedifferentiation of HCC.

Aged↗
PubMed2005

Overexpression of alpha enolase in hepatitis C virus-related hepatocellular carcinoma: association with tumor progression as determined by proteomic analysis.

To identify proteins that could be molecular targets for diagnosis and treatment of hepatitis C virus-related hepatocellular carcinoma (HCV-related HCC), we used a proteomic approach to analyze protein expression in samples of human liver. Twenty-six pairs of tumorous and corresponding nontumorous liver samples from patients with HCV-related HCC and six normal liver samples were analyzed by two-dimensional gel electrophoresis and liquid chromatography-tandem mass spectrometry. One of the numerous spots that showed stronger intensity in tumorous than in nontumorous samples was identified as alpha enolase, a key enzyme in the glycolytic pathway. Expression of this protein increased with tumor dedifferentiation and was significantly higher in poorly differentiated HCC than in well-differentiated HCC. This pattern was reproduced by immunoblot analysis and immunohistochemistry. Expression of alpha enolase also correlated positively with tumor size and venous invasion. These results suggest that alpha enolase is one of the candidates for biomarkers for tumor progression that deserves further investigation in HCV-related HCC.

Aged↗
PubMed2005

Current antibiotic prophylaxis in pancreatoduodenectomy in Japan.

BACKGROUND/PURPOSE: The aim of this study was to investigate the current use of antibiotic prophylaxis (AP) in association with pancreatoduodenectomy (PD) in Japan, and to determine its surgical implications. METHODS: We surveyed 2331 patients who underwent PD for treatment of disease in the periampullary region. Data, obtained during the period January 2002 through December 2003, from 111 major surgical services associated with the Japanese Society for Pancreatic Surgery, were analyzed with regard to patient characteristics, preoperative complications, AP, and postoperative morbidities. RESULTS: Eighty-five (78.7%) of the 108 eligible institutions chose a first- or second-generation cephalosporin for AP, given for a mean duration of 4.3 days. At all but 1 institution, the first dose was administered prior to surgical incision of the skin. At 42% of the institutions, an additional antibiotic was administered during surgery. The overall rate of wound infection was 6.8% of the 2266 patients for whom data were available. Preoperative jaundice was found in 55.3% of these 2266 patients, and 92.6% of these jaundiced patients were suffering from preoperative infections. In addition, those with preoperative infections were also diagnosed as having biliary infections. The number of patients with preoperative jaundice in combination with preoperative infections was significantly related to the rate of postoperative morbidity (P < 0.0001). CONCLUSIONS: Administration of AP in association with PD in Japan seems appropriate. Icteric patients with biliary infections are at high risk for postoperative morbidities and need careful monitoring after surgery.

Antibiotic Prophylaxis↗
PubMed2005

Breast sentinel lymph node navigation with three-dimensional interstitial multidetector-row computed tomographic lymphography.

OBJECTIVE: Three-dimensional multidetector-row computed tomographic lymphography (3D MDCT-LG) with interstitial injection of a widely available nonionic monometric contrast medium iopamidol was used for navigation of breast sentinel lymph node (SLN) biopsy. METHODS: 3D MDCT-LG was obtained after massage of the interstitially injection sites of a total of 4-5 mL undiluted iopamidol at periareolar and peritumoral areas in 68 consecutive patients with early-stage breast cancer, using a 4 detector-row CT scanner. Drainage lymphatic patterns and SLN anatomy were assessed on 3D MDCT-LG images. 3D MDCT-LG-navigated SLN biopsy with combined use of blue dye was followed by backup axillary lymph node dissection to evaluate accuracy of SLN biopsy. RESULTS: The 3D MDCT-LG images clearly localized primary SLNs by visualizing the direct connection between these nodes and their afferent lymphatic vessels on detailed anatomy of the surrounding structures in all patients. Drainage lymphatic pathways on these images were classified into 4 patterns: single route/single SLN (39 cases, 57%), multiple routes/multiple SLNs (10 cases, 15%), single route/multiple SLNs (9 cases, 13%), and multiple routes/single SLN (10 cases, 15%). Under 3D MDCT-LG navigation, SLNs was found at the accurate location in all patients. With backup axillary lymph node dissection, metastasis was found in 14 (20%) patients, and 8 of these patients had metastasis only in the preoperatively identified SLNs. In other 5 positive patients, metastasis was found both in the SLN and non-SLNs. However, micrometastasis eventually was found only in non-SLN in an elderly patient. Overall, the sensitivity, false-negative rate, and accuracy of 3D CT-L-navigated SLN biopsy were 92% (13/14 patients), 7% (1/14 patients), and 98% (67/68 patients), respectively. CONCLUSIONS: Topographic 3D interstitial MDCT-LG can be a widely available and reliable navigator for breast SLN biopsy.

Adult↗