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Yasuhiko Kitadai

Publications and source records attributed to Yasuhiko Kitadai.

At least 19 recordsLinked to original sources
PubMed2007

DNA demethylation of vascular endothelial growth factor-C is associated with gene expression and its possible involvement of lymphangiogenesis in gastric cancer.

Previous studies have indicated that lymphangiogenesis in solid tumors is associated with lymphatic metastasis. Overexpression of Vascular endothelial growth factor (VEGF)-C plays a major role in lymphangiogenesis in cancers. In the present study, DNA methylation and expression of the VEGF-C gene was investigated in gastric cancer (GC). Four GC cell lines (MKN-45, MKN-74, HSC-39 and HSC-43) showed no expression of VEGF-C, and the VEGF-C gene was found to be methylated in these cells. In contrast, 7 GC cell lines (MKN-1, MKN-7, MKN-28, TMK-1, KATO-III, SH101-P4 and HSC-44PE) expressed VEGF-C, and the VEGF-C gene was found to be unmethylated in these cell lines. In addition, expression of VEGF-C mRNA was retrieved by treatment with a demethylating agent, Aza-2'-deoxycytidine. In GC tissue samples, bisulfite DNA sequencing analysis revealed that VEGF-C was not methylated in 9 (29.0%) of 31 GC samples, whereas demethylation was not observed in corresponding non-neoplastic mucosa samples. Overexpression of VEGF-C mRNA was observed in 16 (51.6%) of 31 GC samples by quantitative reverse transcription-polymerase chain reaction. Of the 9 GC cases with VEGF-C demethylation, 8 (88.9%) overexpressed VEGF-C. In contrast, of the 22 GC cases without VEGF-C demethylation, 8 (36.4%) overexpressed VEGF-C (p = 0.0155). Furthermore, lymphatic vessel density determined by immunostaining of podoplanin in GC tissues was associated with overexpression of VEGF-C (p < 0.0001). These results suggest that demethylation and activation of the VEGF-C gene is likely involved in lymphangiogenesis in GC.

Adenocarcinoma↗
PubMed2006

Basis of decreased risk of gastric cancer in severe atrophic gastritis with eradication of Helicobacter pylori.

Helicobacter pylori infection induces chronic gastritis and lowers gastric juice ascorbic acid concentrations. We investigated how H. pylori eradication affected multiple variables that could prevent or delay development of new or occult gastric cancer in patients with early gastric cancer treated by endoscopic mucosal resection. Gastric juice pH, nitrite concentrations, and total vitamin C concentrations, serum concentrations of vitamin C and specific H. pylori antibody, and intensity of neutrophil infiltration in gastric mucosa were determined before and after successful H. pylori eradication. Successful eradication increased acid output and ascorbic acid secretion into gastric juice, accompanied by disappearance of polymorphonuclear infiltration from the surface epithelium and decreased gastric juice nitrite concentrations. Our data suggest that H. pylori eradication decreases the nitrosation rate as the ratio of vitamin C to nitrite increases. This decreases reactive oxygen species and nitric oxide, eliminating their damaging effect on DNA and reducing cell turnover.

Aged↗
PubMed2006

Expression of activated platelet-derived growth factor receptor in stromal cells of human colon carcinomas is associated with metastatic potential.

Platelet-derived growth factor receptor (PDGF-R) expression has been reported in a variety of cancers, including colorectal, breast, lung, ovarian and pancreatic cancers, but the role of PDGF-R expression in the development and progression of colon carcinoma has not yet been elucidated. The purpose of this study was to examine the expression of PDGF and PDGF-R in human colon carcinomas. The expression of PDGF, PDGF-R and phosphorylated PDGF-R (p-PDGF-R) was examined by immunofluorescence in 12 surgical specimens of colon carcinoma and in human colon carcinoma cells growing in the subcutis (ectopic site) and the cecal wall (orthotopic site) of nude mice. In most surgical specimens, tumor cells expressed PDGF-A and -B subunits, without corresponding levels of PDGF-Ralpha and PDGF-Rbeta. PDGF-Rbeta was predominantly expressed by tumor-associated stromal cells and pericytes of tumor vasculature. The expression of PDGF-Rbeta in the stroma was associated with advanced stage disease. Under culture conditions, human colon carcinoma cell lines expressed PDGF-A and -B, but not PDGF-R. In orthotopic tumors, the KM12 cells (Duke's stage B) expressed PDGF-A and -B, but PDGF-Rbeta was expressed only by stromal cells and pericytes in the tumor vasculature. This expression of PDGF-Rbeta by stromal cells and pericytes was higher in tumors growing at the orthotopic site than in those at the ectopic site. The expression of PDGF-Rbeta in the stroma was higher in highly metastatic KM12SM tumors than in low metastatic KM12C tumors. In conclusion, the expression of PDGF-Rbeta in stromal cells is influenced by the organ-specific microenvironment and is associated with metastatic potential.

Animals↗
PubMed2006

Plasticity in urokinase-type plasminogen activator receptor (uPAR) display in colon cancer yields metastable subpopulations oscillating in cell surface uPAR density--implications in tumor progression.

It is becoming increasingly clear that tumor growth and progression is not entirely due to genetic aberrations but also reflective of tumor cell plasticity. It follows therefore that proteins contributing to tumor progression oscillate in their expression a contention yet to be shown. Because the urokinase-type plasminogen activator receptor (uPAR) promotes tumor growth and invasion, we determined whether its expression is itself plastic. In fluorescence-activated cell sorting (FACS), three independent colon cancer clonal populations revealed the expected Gaussian distribution for cell surface uPAR display. However, subcloning of cells collected from the trailing edge of the FACS yielded subpopulations, displaying low cell surface uPAR number. Importantly, these subclones spontaneously reverted to cells enriched in uPAR display, indicating a metastable phenotype. uPAR display plasticity was associated with divergent in vivo behavior with weak tumor growth and progression segregating with receptor deficiency. Mechanistically, reduced uPAR display reflected not repressed gene expression but a switch in uPAR protein trafficking from membrane insertion to shedding. To our knowledge, this is the first demonstration that uPAR cell surface density is oscillatory and we propose that such an event might well contribute to tumor progression.

Alternative Splicing↗
PubMed2006

A case of Crohn's disease with hydronephrosis caused by ureteropelvic junction obstruction.

Ureteral obstruction is a rare extraintestinal manifestation of Crohn's disease (CD). We report the case of a 20-year-old man who presented with fever, diarrhoea, and lower abdominal pain. Diagnostic studies confirmed CD and revealed an abdominal mass obstructing the right ureter and hydronephrosis. Ureteropelvic junction (UPJ) obstruction was diagnosed. Despite an elemental diet and mesalazine therapy, the hydronephrosis persisted, and the patient eventually required surgery. Successful laparoscopic pyeloplasty was performed. This is the first report of CD associated with UPJ obstruction. Ureteral obstruction as a complication of CD is discussed.

Adult↗
PubMed2006

Epstein-Barr virus involvement is a predictive factor for the resistance to chemoradiotherapy of gastric diffuse large B-cell lymphoma.

Primary gastric diffuse large B-cell lymphomas are generally well controlled by non-surgical treatment with combination chemotherapy followed by radiotherapy. We have previously reported that over 90% of patients achieved complete response (CR) with this therapeutic strategy: three cycles of cyclophosphamide, adriamycin, vincristine and prednisone followed by radiotherapy (40.5 Gy). Although the CR rate was very high, some patients still showed resistance to this combination therapy. In order to clarify the factors related to therapy resistance, we examined the relationship between Epstein-Barr virus (EBV), which was examined using an in situ hybridization technique, and the patients' clinical courses. Out of the 50 patients, four were EBV positive; over half of lymphoma cells were positive for EBV by in situ hybridization. Of the three EBV-positive patients, two showed progressive disease and one achieved partial response (PR). Two of the patients died of disease progression. The other patient achieved CR, but the lymphoma recurred with distant metastasis in the cerebellum 3 months after remission. In the present study, eight patients did not achieve CR or they relapsed, four patients showed progressive disease, one patient achieved PR, and three patients achieved CR with recurrence. Therefore, half of these unfavorable patients were EBV positive. This finding strongly indicated that EBV-associated gastric diffuse large B-cell lymphomas frequently show resistance to standard chemoradiotherapy, although some other adverse factors remain unclear.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Targeting the expression of platelet-derived growth factor receptor by reactive stroma inhibits growth and metastasis of human colon carcinoma.

The stromal cells within colon carcinoma express high levels of the platelet-derived growth factor receptor (PDGF-R), whereas colon cancer cells do not. Here, we examined whether blocking PDGF-R could inhibit colon cancer growth in vivo. KM12SM human colon cancer cells were injected subcutaneously (ectopic implantation) into the cecal wall (orthotopic implantation) or into the spleen (experimental liver metastasis) of nude mice. In the colon and liver, the tumors induced active stromal reaction, whereas in the subcutis, the stromal reaction was minimal. Groups of mice (n=10) received saline (control), the tyrosine kinase inhibitor imatinib, irinotecan, or a combination of imatinib and irinotecan. Four weeks of treatment with imatinib and irinotecan significantly inhibited tumor growth (relative to control or single-agent therapy) in the cecum and liver but not in the subcutis. The combination therapy completely inhibited lymph node metastasis. Imatinib alone or in combination with irinotecan inhibited phosphorylation of PDGF-Rbeta of tumor-associated stromal cells and pericytes. Combination therapy also significantly decreased stromal reaction, tumor cell proliferation, and pericyte coverage of tumor microvessels and increased apoptosis of tumor cells and tumor-associated stromal cells. These data demonstrate that blockade of PDGF-R signaling pathways in tumor-associated stromal cells and pericytes inhibits the progressive growth and metastasis of colon cancer cells.

Animals↗
PubMed2006

Deletion of the KIT gene is associated with liver metastasis and poor prognosis in patients with gastrointestinal stromal tumor in the stomach.

The goal of this study was to investigate the association of mutations in the KIT gene and the platelet-derived growth factor receptor alpha (PDGFRA) gene with clinicopathological features of patients with gastrointestinal stromal tumor (GIST) localized in the stomach. We evaluated 56 gastric GISTs for KIT and PDGFRA mutations. DNA was extracted from paraffin-embedded tumor specimens, and exons 9, 11, 13 and 17 of the KIT gene and exons 12 and 18 of the PDGFRA gene were amplified by polymerase chain reaction and sequenced. The genetic features were then compared with the clinicopathological features. Immunohistochemistry was performed for KIT, CD34, Ki-67 (as a marker of cell proliferation) and CD31 (as a marker of microvessel density), and apoptosis was assessed by in situ DNA nick-end labeling. Thirty-four (61%) of the 56 GISTs had a mutation in exon 11 of KIT, and 2 (4%) had a mutation in exon 13 of KIT. Deletions in exon 11 of KIT were the most common mutation encountered in the present study. No mutations were found in exon 9 or 17 of KIT. Six of the 20 GISTs lacking KIT mutations had a mutation in exon 18 of PDGFRA, and 1 had a mutation in exon 12 of PDGFRA. The KIT mutation-positive GISTs showed more frequent liver metastases and higher mortality than KIT mutation-negative GISTs. Our data indicate that KIT mutations, especially deletions in exon 11, are markers of poor prognosis for gastric GISTs.

Antigens, CD↗
PubMed2006

Neuropilin-1 is involved in regulation of apoptosis and migration of human colon cancer.

Vascular endothelial growth factor (VEGF) plays critical roles in cancer aggressiveness. We investigated the clinical and biological significance of neuropilin (NP)-1, a member of the VEGF receptor family, in colon carcinoma. We transfected NP-1-specific small interfering RNA (siRNA) into a human colon adenocarcinoma cell line, WiDR, and investigated its effect on proliferation, migration, and apoptosis. We also examined the relationship between clinicopathologic features and NP-1 expression in 146 patients with advanced colorectal carcinoma who had undergone surgery. Inhibition of NP-1 expression in WiDR cells by RNA interference decreased cell migration (no treatment, 143.3/field; mock, 146.8/field; scrambled siRNA, 134.6/field; NP-1 siRNA 79.6/field) and promoted apoptosis (no treatment, 3.52%; scrambled siRNA, 3.80%; NP-1 siRNA, 14.22%), but did not alter cell proliferation. In patients with advanced colorectal carcinoma, those with tumors with high levels of NP-1 staining showed a significantly higher incidence of lymph node (73.0%) or liver (86.2%) metastasis, greater microvessel density (MVD) (60.4/field), greater number of proliferating carcinoma cells (48.6%), and lesser number of apoptotic carcinoma cells (5.70 per thousand) than those with tumors with low levels of NP-1 staining (lymph node, 56.9%; liver, 59.8%; MVD, 47.8/field; proliferating cells, 42.0%; apoptosis, 8.44 per thousand). Survival for patients with tumors with high levels of NP-1 staining was significantly shorter than for those with tumors with low levels of NP-1 staining. Our results suggest that autocrine-NP-1 pathways control the migration and survival of colon carcinoma cells. NP-1 expression may stimulate tumor growth by enhanced angiogenesis and suppression of tumor cell apoptosis, which lead to metastasis and poor prognosis.

Apoptosis↗
PubMed2006

Genetic and pathologic characteristics of gastrointestinal stromal tumors in extragastric lesions.

The goal of this study was to investigate differences in the clinicopathologic and genetic characteristics of gastric and extragastric gastrointestinal stromal tumors (GISTs). We evaluated 13 extragastric GISTs and compared them with 56 gastric GISTs, which were described previously. DNA was extracted from paraffin-embedded tumor specimens, and exons 9, 11, 13, and 17 of the KIT gene and exons 12 and 18 of the platelet-derived growth factor receptor alpha (PDGFRA) gene were amplified by polymerase chain reaction and sequenced. Immunohistochemistry was performed for KIT, CD34, Ki-67 (as a marker of cell proliferation), and CD31 (as a marker of microvessel density), and apoptosis was assessed by in situ DNA nick end-labeling. Of the 13 extragastric GISTs 7 (54%) had a mutation in exon 11 of KIT, and 2 (15%) had a mutation in exon 13 of KIT. Deletions in exon 11 of KIT were the most common mutation encountered in the extragastric GISTs. The extragastric GISTs, especially small intestinal GISTs, showed larger deletions, leading to deletions of amino acid residues in the KIT protein, and higher vascularity than did the gastric GISTs. These data suggest that extragastric GISTs differ from gastric GISTs with respect to associated mutations and angiogenic activity.

Adult↗
PubMed2005

Simultaneous inhibition of EGFR, VEGFR, and platelet-derived growth factor receptor signaling combined with gemcitabine produces therapy of human pancreatic carcinoma and prolongs survival in an orthotopic nude mouse model.

Although gemcitabine has been approved as the first-line chemotherapeutic reagent for pancreatic cancer, its response rate is low and average survival duration is still only marginal. Because epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR) modulate tumor progression, we hypothesized that inhibition of phosphorylation of all three on tumor cells, tumor-associated endothelial cells, and stroma cells would improve the treatment efficacy of gemcitabine in an orthotopic pancreatic tumor model in nude mice and prolong survival. We implanted L3.6pl, a human pancreatic cancer cell, in the pancreas of nude mice. We found that tumor-associated endothelial cells in this model highly expressed phosphorylated EGFR, VEGFR, and PDGFR. Oral administration of AEE788, a dual tyrosine kinase inhibitor against EGFR and VEGFR, decreased phosphorylation of EGFR and VEGFR. PDGFR phosphorylation was inhibited by STI571. Although i.p. injection of gemcitabine did not inhibit tumor growth, its combination with AEE788 and STI571 produced >80% inhibition of tumor growth and prolonged survival in parallel with increases in number of tumor cells and tumor-associated endothelial cell apoptosis, decreased microvascular density, decreased proliferation rate, and prolonged survival. STI571 treatment also decreased pericyte coverage on tumor-associated endothelial cells. Thus, inhibiting phosphorylation of EGFR, VEGFR, and PDGFR in combination with gemcitabine enhanced the efficacy of gemcitabine, resulting in inhibition of experimental human pancreatic cancer growth and significant prolongation of survival.

Animals↗
PubMed2005

Monocyte chemoattractant protein-1 transfection induces angiogenesis and tumorigenesis of gastric carcinoma in nude mice via macrophage recruitment.

PURPOSE: Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that has various roles in tumor development and progression. We previously reported that expression of MCP-1 is associated with macrophage infiltration and tumor vessel density in human gastric carcinomas. The present study was undertaken to obtain direct evidence that MCP-1 participates in recruitment of macrophages and induction of angiogenesis. EXPERIMENTAL DESIGN: We did transfection experiments to analyze the role of MCP-1 in tumorigenicity and angiogenesis in gastric carcinoma in nude mice. The human MCP-1 gene cloned into the BCMGS-Neo expression vector was transfected into the human gastric carcinoma TMK-1 cell line. We examined tumor volumes with the ectopic s.c. xenograft model and tumorigenicity with the orthotopic gastric xenograft model. We determined intratumor microvessel counts and tumor-infiltrating macrophage counts by immunohistochemical staining. RESULTS: There was no difference in in vitro proliferation between MCP-1-transfected TMK-1 cells and mock-transfected (control) cells; however, MCP-1 transfectants induced tumor growth in ectopic xenografts and increased tumorigenicity and induced lymph node metastases and ascites in orthotopic xenografts. In both ectopic and orthotopic xenograft models, strong infiltration of macrophages was observed within and around the tumors after implantation of MCP-1 transfectants whereas fewer macrophages were seen after inoculation of control cells. The microvessel density was significantly higher in tumors produced by MCP-1 transfectants than in control tumors. CONCLUSIONS: MCP-1 produced by gastric carcinoma cells may regulate angiogenesis via macrophage recruitment. MCP-1 may be a potential target for antiangiogenic therapy for gastric carcinoma.

Animals↗
PubMed2005

Expression of vascular endothelial growth factor (VEGF)-C and VEGF-D in early gastric carcinoma: correlation with clinicopathological parameters.

In this study, we investigated whether expression of vascular endothelial growth factor (VEGF)-C and/or VEGF-D correlates with clinicopathological features of human gastric carcinoma. We immunohistochemically examined the expression of VEGF-C and VEGF-D in 140 archival surgical specimens of submucosally invasive gastric carcinoma. Of these specimens, 32 (22.9%) and 12 (8.6%) showed intense VEGF-C and VEGF-D immunoreactivity in cancer cells, respectively. VEGF-C immunoreactivity was associated with histological type, lymphatic invasion, lymph node metastasis, and microvessel density. No association was identified between VEGF-D immunoreactivity and clinicopathological variables. These results suggest that VEGF-C is a dominant regulator of lymphangiogenesis in early-stage human gastric carcinoma.

Carcinoma↗
PubMed2005

Quantitative analysis of lymphangiogenic markers for predicting metastasis of human gastric carcinoma to lymph nodes.

The spread of tumor cells to regional lymph nodes is an early event of gastric cancer metastasis. In our study, we assessed the expression of lymphangiogenic factors and lymphatic endothelial markers in gastric carcinoma tissues and compared expression levels with the status of lymph node metastasis. We also examined the correlation between lymphatic vessel density (LVD) in primary tumors and lymph node metastasis. Paired biopsy samples (tumor and corresponding normal mucosa) of gastric tissue were obtained from 39 patients with gastric carcinoma. The expression of VEGF-C, VEGF-D, VEGFR-3 and podoplanin mRNAs was assessed by real-time quantitative PCR. The expression of VEGF-C (but not of VEGF-D) was significantly greater in patients with lymph node metastasis than in those without metastasis. The expression of lymphatic endothelial markers VEGFR-3 and podoplanin was also significantly greater in the node-positive group. LVD, as assessed by immunohistochemistry for podoplanin, was correlated with lymph node metastasis. These results indicate that quantitative analysis of lymphangiogenic markers in gastric biopsy specimens may be useful in predicting metastasis of gastric cancer to regional lymph nodes.

Biomarkers, Tumor↗
PubMed2005

A combination of the Helicobacter pylori stool antigen test and urea breath test is useful for clinical evaluation of eradication therapy: a multicenter study.

BACKGROUND: Helicobacter pylori stool antigen (HpSA) test is a new tool for evaluating the H. pylori infection. The present study was carried out to investigate the clinical usefulness of the HpSA test in the evaluation of eradication therapy by comparing it with the (13)C-urea breath test (UBT). METHODS: One hundred and five patients received eradication therapy for H. pylori. After more than 8 weeks, the success of the therapy was evaluated by the HpSA test and the UBT. Concordant results were regarded as a final diagnosis, but when the results were discordant, histological examination was carried out. RESULTS: Of the 105 patients receiving eradication therapy for H. pylori, 25 patients were regarded as H. pylori positive by the UBT and and 20 patients were regarded as H. pylori positive by the the HpSA test. Nine patients (8.6%) showed discordant results (seven cases with UBT(+) and HpSA(-), and two with UBT(-) and HpSA(+)). Five cases out of nine were ultimately judged as having a false-positive result of the UBT, and in these cases the UBT values were relatively low (below 10 per thousand). The final diagnostic accuracies of the UBT and the HpSA test were 94.3% (88.0-97.9%; 95% CI) and 97.1% (91.9-99.4%), respectively. When we used the HpSA test in cases with weakly positive UBT values, we were able to diagnose the correct status of H. pylori infection after eradication in 99% of all patients (94.8-100.0%). CONCLUSION: The HpSA test is a useful tool for the evaluation of eradication therapy and a combination of the HpSA test and UBT is clinically recommended.

Adult↗
PubMed2005

A single nucleotide polymorphism in the 5' untranslated region of the EGF gene is associated with occurrence and malignant progression of gastric cancer.

OBJECTIVE: Epidermal growth factor (EGF) has many biological functions and plays an important role in the progression of various tumors including gastric cancer. An A-G single nucleotide polymorphism (SNP) at position 61 in the 5'-untranslated region (UTR) of the EGF gene has recently been reported to be associated with different levels of EGF production. We examined whether this polymorphism is correlated with the development and malignant phenotypes of gastric cancer. METHODS: The study population included 200 gastric cancer patients and 230 healthy control subjects. The SNP in the 5'-UTR of the EGF gene was analyzed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: The A allele was significantly less frequent in patients than in controls (p = 0.01). Individuals with the A/A or A/G genotype showed a significantly lower risk of gastric cancer than those with the G/G genotype [adjusted odds ratio (OR) = 0.56], whereas the same genotypes were associated with malignant progression of this cancer, e.g. deeper tumor invasion, increased lymph node metastasis and advanced clinical stage, and histological classification in gastric cancer patients (adjusted OR = 1.80, 1.98, 2.26 and 1.89, respectively). CONCLUSIONS: Our findings suggest that the A-G polymorphism of EGF is involved not only in the occurrence but also in the malignant progression of gastric cancer.

5' Flanking Region↗
PubMed2005

Expression of p53 protein in esophageal squamous cell carcinoma: relation to hypoxia-inducible factor-1alpha, angiogenesis and apoptosis.

OBJECTIVES: Hypoxia-inducible factor (HIF)-1 is important in the control of transcription of several genes related to angiogenesis. We have previously reported that expression of HIF-1alpha correlates with venous invasion and clinical outcome in esophageal squamous cell carcinoma. p53 has been reported to interact with HIF-1alpha and induce ubiquitin-mediated proteosomal degradation of HIF-1alpha. The purpose of this study was to clarify whether the expression of p53 is associated with that of HIF-1alpha. METHODS: Expression of p53, HIF-1alpha and vascular endothelial growth factor (VEGF) was examined in 81 archival surgical specimens of human esophageal squamous cell carcinoma tissue. CD34 and single-stranded DNA were used to evaluate angiogenesis and apoptosis. RESULTS: Forty-seven of the 81 (58.0%) tumor specimens showed high levels of nuclear p53 immunoreactivity. Overexpression of p53 was observed in the early clinical stage of tumor development. Expression of p53 was not correlated with HIF-1alpha or VEGF expression, angiogenesis or apoptosis in esophageal carcinoma. CONCLUSIONS: These results suggest that mutations in p53 play a role in carcinogenesis but not in the progression of esophageal squamous cell carcinoma. HIF-1alpha may not only be regulated by p53 but also by other factors.

Aged↗