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Biomedical subjects

Kazuhiro Yoshida

Publications and source records attributed to Kazuhiro Yoshida.

At least 55 records · Page 3Linked to original sources

Clinical evaluation of low-dose cisplatin and 5-fluorouracil as adjuvant chemoradiotherapy for advanced squamous cell carcinoma of the esophagus.

The aim of this retrospective study was to evaluate the effectiveness of low-dose cisplatin and 5-fluorouracil (low-dose FP) as an adjuvant chemoradiotherapy for resected advanced squamous cell carcinoma of the esophagus. From 1994 to 1999, 57 patients who showed an invasion of the tumor over the muscularis propria (T2-T4), regional lymph node metastasis (N1), and no distant metastasis (M0) were enrolled in this analysis. Postoperative chemoradiotherapy (CRT group) was performed on 14 of the patients, and they were compared to the patients who underwent surgery alone (S group) using the matched pair algorithm. In the CRT group, chemotherapy of low-dose FP was combined with concurrent radiotherapy after the esophagectomy. A side-effect of severe dysphagia (NCI-CTC Grade 3) was observed in 4 patients (28.6%) and leukocytopenia in 1 patient (7.1%) among the CRT group. The overall survival rate of the CRT group and matched S group were 35.7% and 28.5% at 5 years, respectively, with no significant difference. In the CRT group, 7 of 14 patients (50%) had a recurrence. The recurrence rate was slightly lower than in the S group (57%), with no significant difference. This combined chemoradiotherapy using low-dose FP did not improve the prognosis of patients with resected advanced esophageal carcinoma.

Aged↗

No evidence of correlation between the single nucleotide polymorphism of DNMT3B promoter and gastric cancer risk in a Japanese population.

DNA methylation is a major epigenetic modification in humans, and aberrant DNA methylation may play an important role in the development of various cancers through the silencing of some tumor suppressor genes. DNMT3B is required for the establishment and maintenance of genomic methylation patterns. The -149 C/T single nucleotide polymorphism (SNP) in the promoter of DNMT3B has been identified. This SNP influences DNMT3B promoter function, with the T allele having greater activity than the C allele, and is associated with an increased risk of lung cancer. The purpose of our study was to investigate the correlation between the DNMT3B promoter polymorphism and the development and progression of gastric cancer. We analyzed the SNP of the DNMT3B promoter in 152 gastric cancer patients and 247 controls from a Japanese population using PCR-RFLP and sequencing analysis, and also studied the association between the genotypes of DNMT3B and clinicopathological parameters among cases. Allelic difference was not found between gastric cancer patients and control subjects at the target site, -149 bp from the transcriptional start site in the DNMT3B gene promoter. Only the T/T genotype was detected in all gastric cancer patients and control subjects. We concluded that there was no association between SNP of the DNMT3B promoter and gastric cancer risk in a Japanese population.

Case-Control Studies↗

Intractable gastrointestinal bleeding from angiodysplasia in a patient of Bernard-Soulier syndrome--report of a case--.

We herein report a case of gastrointestinal bleeding induced by angiodysplasia of the cecum in a case of Bernard-Soulier syndrome with recurrent breast cancer. In spite of endoscopic hemostatic therapy and interventional embolization, she had repeated massive bleeding from the cecal lesion. In addition, she had chronic hepatitis C and progressive liver tumors metastasized from breast cancer, and she finally died of hepatic failure. There are four case reports in the literature describing Bernard-Soulier syndrome with gastrointestinal bleeding angiodysplasia. The reported cases benefited from hormonal, endoscopical hemostasis and surgical therapy. In our case, because of her terminal metastatic breast cancer, only conservative treatments were administered after the third bleed. Both the endoscopic hemostatic method and interventional embolization showed only a temporary effect. Surgical treatment should be considered if the general condition can tolerate a surgical procedure.

Angiodysplasia↗

Epigenetic inactivation of SOCS-1 by CpG island hypermethylation in human gastric carcinoma.

Suppressor of cytokine signaling (SOCS)-1 inhibits signaling of the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway by several cytokines and has tumor suppressor activity. Methylation of the SOCS-1 CpG island has been shown to inactivate the SOCS-1 gene in certain human cancers. In our study, we investigated methylation status of the SOCS-1 gene by methylation-specific PCR in 75 gastric carcinoma (GC) tissues, 25 corresponding nonneoplastic mucosae and 10 normal gastric mucosae from healthy young individuals. We also performed bisulfite sequencing of DNAs from 2 GC tissues. In addition, SOCS-1 mRNA levels were examined in 50 GCs by quantitative RT-PCR. Hypermethylation of the SOCS-1 gene was detected in 33 (44%) of 75 GC tissues and in 3 (12%) of 25 corresponding nonneoplastic mucosae; the incidence was significantly different (p = 0.004). None of the 10 normal gastric tissues from healthy individuals showed hypermethylation. Methylation of the SOCS-1 gene was associated with lymph node metastasis, advanced tumor stage and reduced expression of SOCS-1 in GC tissues (p = 0.009, 0.034 and 0.002, respectively). Reduced expression of SOCS-1 in GC tissues was associated with lymph node metastasis and advanced tumor stage (p = 0.013 and 0.002, respectively). Our results suggest that transcriptional inactivation of the SOCS-1 gene by hypermethylation may be involved in development, progression and metastasis of GC.

Carcinoma↗

N-H insertion reactions of primary ureas: the synthesis of highly substituted imidazolones and imidazoles from diazocarbonyls.

Primary ureas have been used as substrates in rhodium-catalyzed N-H insertion reactions with an array of diazocarbonyls. The insertion reaction is efficient and gives excellent selectivity and yields. The products from the insertion reaction with diazoketones cyclize readily in the presence of acid to yield the corresponding imidazolones that can be further derivatized by N-alkylation with alkyl, allyl, and benzyl halides. Alternatively, the imidazolones were treated with phosphorus oxybromide to form the corresponding 2-bromoimidazoles that were further functionalized using a Suzuki coupling reaction.

Azo Compounds↗

N-h insertion reactions of Boc-amino acid amides: solution- and solid-phase synthesis of pyrazinones and pyrazines.

A series of alpha-diazo-beta-ketoesters were reacted with Boc amino acid amides in the presence of rhodium octanoate catalyst. The resulting N-H insertion products were treated with acid, providing the 1,4-azine intermediates, which were oxidized by air to form the corresponding pyrazine-6-one products. The pyrazine-6-ones were further derivatized by N-alkylation or by conversion to the arylpyrazines using sequential bromination and Suzuki coupling reactions. [reaction: see text]

Amino Acids↗

PDZK1 directly regulates the function of organic cation/carnitine transporter OCTN2.

Urinary excretion of cationic xenobiotics is believed to be mediated by organic cation transporter (OCT and OCTN) families expressed on both basolateral and brush-border membranes of renal tubules, although the molecular mechanisms for targeting of these transporters to each membrane are poorly understood. Here, to examine the regulatory mechanisms for cell-surface expression and function of these transporters, we evaluated the interaction of these transporters with several PDZ proteins. A pull-down study using recombinant C-terminal proteins of OCTs and OCTNs identified a specific interaction of apical transporters OCTN1 and OCTN2, but not basolateral transporters OCT1 and OCT2, with PDZK1, intestinal and kidney-enriched PDZ protein, and Na+/H+ exchanger regulatory factor 2 (also called E3KARP, SIP-1, or TKA-1). Both yeast two-hybrid and pull-down studies suggested a requirement of the last four amino acids in OCTN1 and OCTN2 for the interaction. The interaction of PDZK1 with the C terminus of OCTN2 was also confirmed in a pull-down study using kidney brush-border membrane vesicles. Immunohistochemical analysis revealed that both PDZK1 and OCTN2 are colocalized in brush-border membranes of the kidney. Finally, double transfection of OCTN2 with PDZK1 stimulated the uptake by OCTN2 of its endogenous substrate carnitine, and this increase could be accounted for by the 6-fold increase in transport capacity. Such an increase was not observed for OCTN2 with deletion of the last four amino acids. Biotinylation study of surface proteins revealed minimal effect of PDZK1 on cell-surface expression of OCTN2. The present findings are the first to identify PDZK1 as a functional regulator of OCTN2 through direct interaction with the C terminus.

Amino Acid Sequence↗

A single nucleotide polymorphism in the MMP-9 promoter affects tumor progression and invasive phenotype of gastric cancer.

PURPOSE: Matrix metalloproteinase-9 (MMP-9, gelatinase B) plays a key role in cancer invasion and metastasis by degradating the extracellular matrix (ECM) and basement membrane barriers. A cytosine (C)-thymidine (T) single nucleotide polymorphism (SNP) at position -1562 in the MMP-9 promoter is reported to affect expression of this gene. The purpose of this study was to investigate the relation between the -1562 C/T polymorphism and the development and progression of gastric cancer. METHODS: The study population included 177 gastric cancer patients and 224 healthy control subjects. The SNP in the MMP-9 promoter was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing. Genotype frequencies were compared between patients and controls, and the association of genotypes with clinicopathological features was studied. RESULTS: Genotype frequencies in gastric cancer patients were similar to those in control subjects (P = 0.223). However, significant association was found between degree of tumor invasion, clinical stage, and lymphatic invasion and the MMP-9 polymorphism in gastric cancer patients (P<0.05, for each). CONCLUSIONS: Our results indicate that the T allele in the MMP-9 promoter is associated with the invasive phenotype of gastric cancer.

Aged↗

Concise prediction models of anticancer efficacy of 8 drugs using expression data from 12 selected genes.

We developed concise, accurate prediction models of the in vitro activity for 8 anticancer drugs (5-FU, CDDP, MMC, DOX, CPT-11, SN-38, TXL and TXT), along with individual clinical responses to 5-FU using expression data of 12 genes. We first performed cDNA microarray analysis and MTT assay of 19 human cancer cell lines to sort out genes which were correlative in expression levels with cytotoxicities of the 8 drugs; we selected 13 genes with proven functional significance to drug sensitivity from a huge number of potent prediction marker genes. The correlation significance of each was confirmed using expression data quantified by real-time RT-PCR, and finally 12 genes (ABCB1, ABCG2, CYP2C8, CYP3A4, DPYD, GSTP1, MGMT, NQO1, POR, TOP2A, TUBB and TYMS) were selected as more reliable predictors of drug response. Using multiple regression analysis, we fixed 8 prediction formulae which embraced the variable expressions of the 12 genes and arranged them in order, to predict the efficacy of the drugs by referring to the value of Akaike's information criterion for each sample. These formulae appeared to accurately predict the in vitro efficacy of the drugs. For the first clinical application model, we fixed prediction formulae for individual clinical response to 5-FU in the same way using 41 clinical samples obtained from 30 gastric cancer patients and found to be of predictive value in terms of survival, time to treatment failure and tumor growth. None of the 12 selected genes alone could predict such clinical responses.

Antimetabolites, Antineoplastic↗

Frequent epigenetic inactivation of RIZ1 by promoter hypermethylation in human gastric carcinoma.

The retinoblastoma protein-interacting zinc finger gene, RIZ1 (GenBank accession number U17838), is involved in chromatin-mediated gene expression and is also a target for frameshift mutation in microsatellite-unstable cancers. Methylation of the RIZ1 promoter CpG island has been shown to be a common mechanism in inactivating the RIZ1 gene in human liver and breast cancers. We investigated levels of RIZ1 mRNA in 45 gastric carcinoma tissues by quantitative RT-PCR and in gastric carcinoma cell lines by RT-PCR. In addition, we examined CpG island methylator phenotype (CIMP) status, p53 mutation status, and the correlation between promoter methylation status and RIZ1 mRNA expression. CIMP status was investigated by examining the methylation status of MINT1, MINT2, MINT12, MINT25 and MINT31. p53 mutation status was examined by PCR-single strand conformation polymorphism and promoter methylation status was examined by methylation-specific PCR. Promoter hypermethylation of the RIZ1 gene was found in 31 (69%) of 45 gastric carcinoma tissues and in 3 (21%) of 14 corresponding non-neoplastic mucosae, the incidence being significantly different (p = 0.002). None of the 12 normal gastric tissues from young non-cancer individuals showed hypermethylation. Promoter hypermethylation was associated with reduced RIZ1 expression in gastric carcinoma tissues (p = 0.029). Promoter hypermethylation of the RIZ1 gene was significantly associated with CIMP (p = 0.002). Mutation status of the p53 gene was not associated with methylation status or RIZ1 expression in gastric carcinoma. In gastric carcinoma cell lines MKN-28 and KATO-III, the RIZ1 promoter was hypermethylated and RIZ1 transcription was inactive. Treatment of these cells with demethylating agent 5-aza-2'-deoxycytidine restored RIZ1 transcription. Our results suggest that transcriptional inactivation of the RIZ1 gene by promoter hypermethylation may participate in stomach carcinogenesis.

Cell Line, Tumor↗

Expression of Cbl linking with the epidermal growth factor receptor system is associated with tumor progression and poor prognosis of human gastric carcinoma.

Cbl proteins play important roles in downregulation of growth factor receptors by acting as ubiquitin ligases and multi-adapter proteins. Ligand-induced desensitization of the epidermal growth factor receptor (EGFR) has been shown to be controlled by Cbl. In the present study, we examined the expression of Cbl in gastric carcinomas and studied the correlation of Cbl expression with clinicopathological characteristics as well as EGFR expression. Cbl protein was expressed in 67% (82/122) of gastric carcinomas, and diffuse expression of Cbl was detected in 29% (35/122) of the cases. The incidence of cases with diffuse expression of Cbl was significantly higher in advanced cases (28/70, 40%) than in early cases (7/52, 14%) (P=0.0010). Diffuse expression of Cbl was significantly associated with metastasis of tumor cells in lymph nodes (P=0.0318). Diffuse expression of EGFR was significantly associated with depth of invasion (P=0.0057), lymph-node metastasis (P=0.0371) and tumor stages (P=0.0278). As the grades of Cbl expression became stronger, the cases with diffuse EGFR expression increased, the positive correlation being significant (P=0.049). All the cases with diffuse expression of Cbl and EGFR were found to show nodal metastasis and to be at an advanced stage. Moreover, the prognosis of the patients with synchronous diffuse expression of Cbl and EGFR was significantly poorer than that of the patients negative for Cbl and focal or negative for EGFR (P=0.0086). The expression of Cbl protein was clearly induced in gastric carcinoma cell lines by transforming growth factor-alpha treatment. These results suggest that Cbl in connection with the EGFR system may be associated with stomach carcinogenesis, invasion and metastasis. Cbl may serve as a novel molecular marker for aggressive gastric carcinoma.

Adenocarcinoma↗

Mechanistic studies on the catalytic cycle of rhodium-catalyzed asymmetric 1,4-addition of aryltitanate reagents to alpha,beta-unsaturated ketones.

Addition of lithium aryl(tetraisopropoxy)titanates [ArTi(OPr-i)(4)(-)Li(+)] to alpha,beta-unsaturated ketones proceeded with high enantioselectivity (up to 99% ee) in the presence of an excess amount of chlorotrimethylsilane and a rhodium catalyst (3 mol % Rh), generated from [RhCl(C(2)H(4))(2)](2) and (S)-binap, in tetrahydrofuran at 20 degrees C to give high yields of the corresponding silyl enolates as 1,4-addition products. The presence of chlorotrimethylsilane is essential for the 1,4-addition to take place. (31)P NMR spectroscopic studies revealed that the catalytic cycle consists of three transformations, that is, (i) insertion of an enone into arylrhodium species forming (oxa-pi-allyl)rhodium intermediate, (ii) silylation of the (oxa-pi-allyl)rhodium with chlorotrimethylsilane giving silyl enolate and a chloro-rhodium complex, and (iii) transmetalation of aryl group from aryltitanate to the chloro-rhodium regenerating the aryl-rhodium.

Journal Article↗

A single nucleotide polymorphism in the MMP-1 promoter is correlated with histological differentiation of gastric cancer.

PURPOSE: Matrix metalloproteinase-1 (MMP-1) plays a key role in cancer invasion and metastasis by degradation of extracellular matrix (ECM) and basement membrane barriers. The 1G/2G single nucleotide polymorphism (SNP) in the MMP-1 promoter at position -1607 bp has been reported to affect the transcriptional activity. In the light of these findings, we investigated whether this SNP in the MMP-1 promoter is associated with the development, differentiation, and progression of gastric cancer. METHODS: The 215 gastric cancer patients and 166 controls were used in this study. The SNP of the MMP-1 promoter was analyzed by PCR-RFLP and sequencing. The genotype frequency was compared between cases and controls, and the association with clinicopathological parameters among cases was studied. RESULTS: The frequency of 1G/2G genotypes in gastric cancer patients was similar to those in controls (p=0.57). The degree of tumor invasion, the presence of lymph node metastasis, and clinical stage showed no significant association with the SNP. On the other hand, we found a significant association with histological differentiation and gender among gastric cancer patients (p<0.05, respectively). CONCLUSIONS: The presence of 2G allele in the MMP-1 promoter did not enhance the risk of gastric cancer; however, it may be involved in differentiation of gastric cancer.

Aged↗

Expression of POT1 is associated with tumor stage and telomere length in gastric carcinoma.

Pot1, a telomere end-binding protein in fission yeast and human, is proposed not only to cap telomeres but also to recruit telomerase to the ends of chromosomes. No study has been performed regarding Pot1 expression status in human cancers. Thus, we examined POT1 mRNA expression in 51 gastric cancer (GC) tissues and evaluated telomere length and 3' telomeric overhang signals in 20 of the 51 GC tissues. Quantitative reverse transcription-PCR analysis showed that POT1 expression levels in the tumor relative to those in nonneoplastic mucosa (T/N ratio) were significantly higher in stage III/IV tumors than in stage I/II tumors (P = 0.005). Down-regulation of POT1 (T/n < 0.5) was observed more frequently in stage I/II GC (52.4%, 11 of 21) than in stage III/IV GC (23.3%, 7 of 30; P = 0.033), whereas up-regulation of POT1 (T/n > 2.0) was observed more frequently in stage III/IV GC (33.3%, 10 of 30) than in stage I/II GC (9.5%, 2 of 21; P = 0.048). POT1 expression levels showed decreased in accordance with telomere shortening (r = 0.713, P = 0.002). In-gel hybridization analysis showed that 3' telomeric overhang signals decreased in accordance with decreases in POT1 expression levels (r = 0.696, P = 0.002) and telomere shortening (r = 0.570, P = 0.013). Reduced POT1 expression was observed in GC cell lines with telomeres shortened by treatment with azidothymidine. In addition, inhibition of Pot1 by antisense oligonucleotides led to telomere shortening as well as inhibition of telomerase activity in GC cells. Moreover, inhibition of Pot1 decreased 3' overhang signals and increased the frequency of anaphase bridge (P = 0.0005). These data suggest that Pot1 may play an important role in regulation of telomere length and that inhibition of Pot1 may induce telomere dysfunction. Moreover, changes in POT1 expression levels may be associated with stomach carcinogenesis and GC progression.

3' Untranslated Regions↗

Expression of hypoxia-inducible factor (HIF)-1alpha is associated with vascular endothelial growth factor expression and tumour angiogenesis in human oesophageal squamous cell carcinoma.

The purpose of this study was to examine the relationship between hypoxia inducible factor (HIF)-1alpha expression, vascular endothelial growth factor (VEGF) expression, and tumour vascularity in squamous cell carcinoma of the oesophagus. Expression of HIF-1alpha and VEGF was examined in two oesophageal squamous cell carcinoma cell lines (TE2, TE3) and 82 archival surgical specimens of human oesophageal squamous cell carcinoma tissue. In both cell lines, the levels of HIF-1alpha protein and VEGF mRNA were increased under hypoxic conditions. Thirty-two of the 82 (39%) tumour specimens showed high levels of HIF-1alpha immunoreactivity in the nuclei and/or cytoplasm of cancer cells. HIF-1alpha expression correlated significantly with venous invasion, VEGF expression, and microvessel density. Among the 47 patients who did not receive pre-operative chemotherapy, the outcome of those with high HIF-1alpha-expressing tumours was significantly poorer than that of those with low HIF-1alpha-expressing tumours. These results suggest that HIF-1alpha and VEGF expression are important determinants of survival in squamous cell carcinoma of the oesophagus.

Blotting, Western↗

Screening of the interaction between xenobiotic transporters and PDZ proteins.

PURPOSE: Xenobiotic transporters have been proposed to be involved in membrane penetration of various therapeutic agents. As little information is available on molecular mechanism of their functional regulation, we have attempted to clarify the protein-protein interactions of such transporters as a first step to identify their regulators. METHODS: Yeast two-hybrid screening was performed to examine the interaction between carboxylic terminus of various xenobiotic transporters and PDZ (PSD95, D1g and ZO1) domain-containing proteins. The interaction and functional regulation were also evaluated in pull-down, immunoprecipitation and transport studies. RESULTS: Specific interaction with PDZ proteins was identified for several xenobiotic transporters including PEPT1, PEPT2, OCT3, OCTN1, OCTN2, OAT4, OATP-A, OATP-D, and OATP-F. The potent interaction was observed between PEPT2 and PDZK1, and deletion of the last four amino acids of the PEPT2 C-terminus almost completely abrogated such interaction. Recombinant PEPT2 C-terminus fusion protein can bind to purified His6-tagged PDZK1, confirming the involvement of two of four PDZ domains within PDZK1 in the interaction. Alanine-scanning mutation in PEPT2 revealed the presence of a consensus sequence (-T-X-L) that is responsible for the PDZK1 interaction. Transfection of PDZK1 increased the uptake of glycylsarcosine by PEPT2, whereas such stimulation was not observed for PEPT2 with the last four amino acids deleted. CONCLUSIONS: These results first identified the interaction between PDZ proteins and the cytosolic tail of various xenobiotic transporters. PDZK1 directly interacts with PEPT2, exerting functional regulation of its transporting activity. The current findings imply the localization of PEPT2 within a protein network constructed from PDZK1 and other transporter proteins.

Carrier Proteins↗

Granulocyte adsorptive apheresis for leg ulcers complicated by rheumatoid arthritis: a report on three successfully treated cases.

BACKGROUND: The treatment of inflammatory leg ulcers complicated by rheumatoid arthritis (RA), which are unresponsive to conventional care, can be frustrating. Furthermore, as granulocytes and monocytes (GM) are major sources of inflammatory cytokines, they have the potential to initiate and perpetuate inflammatory skin lesions. Accordingly, a recent study reported the remission of pyoderma gangrenosum following the reduction of activated peripheral blood GM by adsorptive apheresis (GMA). METHODS: In this clinical study, we applied GMA to three cases, each with one leg ulcer below the knee and RA. The ulcers had not responded to conventional therapy, including disinfection, dressing, and antimicrobials, and therefore were thought to represent inflammatory vasculitic lesions. GMA was performed using a column with a capacity of 335 mL, filled with cellulose acetate beads that selectively adsorb granulocytes and monocytes/macrophages (Adacolumn). Each patient received one GMA session/week for five consecutive weeks. The duration of one session was 60 min, with a flow rate of 30 mL/min. RESULTS: The ulcers began to recede after two GMA sessions and, by the end of the fifth session, the ulcers in all three patients had healed. No recurrence has been observed up to the time of this report. The treatment was well tolerated and no severe side-effects were observed. CONCLUSIONS: GMA, which depletes activated neutrophils and monocytes/macrophages, appears to be effective for inflammatory skin ulcers which do not respond to conventional medications.

Aged↗

Expression of RHOC is associated with metastasis of gastric carcinomas.

OBJECTIVES: RHOC, a member of the RAS-related small GTPase protein family, regulates cytoskeletal structures and has the potential to transform cultured cells. It has recently been reported that RHOC contributes to the metastatic phenotype of melanoma cells. The purpose of this study was to clarify its biological relevance to gastric carcinogenesis and metastasis. METHODS: We examined the expression of RHOC by quantitative RT-PCR in 51 cases of gastric carcinoma tissues from prior surgical cases (intestinal type: 24 cases, diffuse type: 27 cases) and in 8 gastric carcinoma cell lines. RESULTS: RHOC expression levels in primary tumors were significantly higher in cases with metastasis than in those without metastasis (p = 0.0202; Mann-Whitney U test). RHOC expression levels in primary tumor and their metastatic tumors were significantly higher than their corresponding nonneoplastic mucosa (p = 0.0357, and 0.0173, respectively; Wilcoxon signed rank test). RHOC mRNA expression was confirmed in the gastric carcinoma cell lines. CONCLUSION: Our findings suggest that elevated expression of the RHOC gene may be involved in the metastasis of gastric carcinomas and may be a good genetic marker for the prediction of a metastatic potential.

Adult↗