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Tetsuro Kubota

Publications and source records attributed to Tetsuro Kubota.

At least 19 recordsLinked to original sources
PubMed2003

Lewis type 1 antigen synthase (beta3Gal-T5) is transcriptionally regulated by homeoproteins.

The type 1 carbohydrate chain, Galbeta1-3GlcNAc, is synthesized by UDP-galactose:beta-N-acetylglucosamine beta1,3-galactosyltransferase (beta3Gal-T). Among six beta3Gal-Ts cloned to date, beta3Gal-T5 is an essential enzyme for the synthesis of type 1 chain in epithelium of digestive tracts or pancreatic tissue. It forms the type 1 structure on glycoproteins produced from such tissues. In the present study, we found that the transcriptional regulation of the beta3Gal-T5 gene is controlled by homeoproteins, i.e. members of caudal-related homeobox protein (Cdx) and hepatocyte nuclear factor (HNF) families. We found an important region (-151 to -121 from the transcription initiation site), named the beta3Gal-T5 control element (GCE), for the promoter activity. GCE contained the consensus sequences for members of the Cdx and HNF families. Mutations introduced into this sequence abolished the transcriptional activity. Four factors, Cdx1, Cdx2, HNF1alpha, and HNF1beta, could bind to GCE and transcriptionally activate the beta3Gal-T5 gene. Transcriptional regulation of the beta3Gal-T5 gene was consistent with that of members of the Cdx and HNF1 families in two in vivo systems. 1) During in vitro differentiation of Caco-2 cells, transcriptional up-regulation of beta3Gal-T5 was observed in correlation with the increase in transcripts for Cdx2 and HNF1alpha. 2) Both transcript and protein levels of beta3Gal-T5 were determined to be significantly reduced in colon cancer. This down-regulation was correlated with the decrease of Cdx1 and HNF1beta expression in cancer tissue. This is the first finding that a glycosyltransferase gene is transcriptionally regulated under the control of homeoproteins in a tissue-specific manner. beta3Gal-T5, controlled by the intestinal homeoproteins, may play an important role in the specific function of intestinal cells by modifying the carbohydrate structure of glycoproteins.

Amino Acid Motifs↗
PubMed2003

Chemosensitivity testing--present and future in Japan.

Radical surgery with extended lymph node dissection is the first and only curative treatment of gastrointestinal cancer. Although the combined cancer chemotherapy has achieved 30%-50% response rates, a controversy still remains over the significance of the adjuvant cancer chemotherapy after surgery. To break through this limitation, we have introduced the chemosensitivity test to evaluate the appropriate adjuvant cancer chemotherapy for advanced gastrointestinal cancer. Our plural studies indicated that the chemosensitivity test would be useful in evaluating the appropriated adjuvant chemotherapy by increasing survival in the sensitive group. Recently, the molecular targets have been clarified for the conventionally available antitumor agents, e.g., thymidylate synthetase for 5-fluorouracil, ATP-binding cassette transporters for anthracyclines, glutathione-related detoxification for platins, and topoisomerase I for CPT-11, which will be applied for dinical use in evaluating the appropriate cancer chemotherapy. The chemosensitivity test is approved as "advanced clinical medicine" by the Japanese Ministry of Health, Welfare, and Labor in five institutes at present. Because complete dissection and chemosensitivity test-guided adjuvant chemotherapy will result in a survival benefit for patients with advanced gastrointestinal cancer, this test should be approved as "social insurance" for further wide clinical application.

Antineoplastic Agents↗
PubMed2003

Combined antitumor activity of 7-hydroxystaurosporine (UCN-01) and tamoxifen against human breast carcinoma in vitro and in vivo.

BACKGROUND: 7-Hydroxystaurosporine (UCN-01) was originally isolated as a protein kinase C inhibitor and has shown antitumor activity against several human cancer cell lines. UCN-01 inhibits cell cycle progression from the G1 to the S phase and is associated with inhibition of cyclin-dependent kinase (CDK) activity and induction of intrinsic CDK inhibitor p21, leading to dephosphorylation of retinoblastoma (Rb) protein. Tamoxifen (TAM) traps cancer cells in the G1 phase, suggesting that the mechanism of action of TAM is similar to that of UCN-01. The present study was conducted to assess the antitumor activity of UCN-01 combined with TAM against human breast carcinoma cells in vitro and in vivo. MATERIALS AND METHODS: MCF-7 cells were treated with UCN-01, TAM, or UCN-01 combined with TAM at various concentrations in vitro. The antitumor effect was evaluated as the inhibition rate (I.R.%) by MTT assay. Two human breast carcinoma xenografts in nude mice, MCF-7 and Br-10, were treated with UCN-01, TAM or both agents together. The expression of p21 and the phosphorylation status of Rb protein in MCF-7 cells were detected by Western blotting. RESULTS: UCN-01 or TAM alone inhibited the proliferation of MCF-7 cells in a concentration-dependent manner. Combined treatment with UCN-01 followed by TAM inhibited the growth of MCF-7 cells synergistically and no significant differences in cytotoxicity were observed between the different sequences of UCN-01/TAM and TAM/UCN-01. Combination treatment with UCN-01 and TAM against MCF-7 and Br-10 in vivo exhibited superior antitumor effects compared with either agent treatment alone. Although 0.1 microg UCN-01 per ml (I.R.: 48.1%) or 2 microM TAM (I.R.: 31%) induced p21 expression, phosphorylation of Rb protein was not inhibited. However, combination treatment with UCN-01 and TAM at the same concentrations resulted in an I.R. of 67% and dephosphorylation of Rb protein. CONCLUSION: The present study suggests that combining UCN-01 and TAM could result in augmented cytotoxicity because of their similar mechanism of action. This combination may have potential clinical applications for breast cancer treatment, by reducing the toxicity of UCN-01.

Animals↗
PubMed2003

5-fluorouracil and dihydropyrimidine dehydrogenase.

Dihydropyrimidine dehydrogenase (DPD) is a rate-limiting enzyme of (fluorinated) pyrimidine degradation that plays a significant role in the pharmacokinetics of 5-fluorouracil (5-FU). In addition, a catabolite of 5-FU induces a certain toxicity, and the sensitivity of 5-FU is determined by DPD activity in tumors. DPD is thus important clinically. Drugs have been developed that control variations of the pharmacokinetics of 5-FU by controlling or inhibiting DPD, thereby reducing toxicity and improving sensitivity. These fluorinated pyrimidines with DPD-inhibiting activity, called DPD-inhibitory fluoropyrimidines, contribute to oral therapy with 5-FU for cancer. This paper summarizes the important role of DPD in cancer chemotherapy with 5-FU.

Antimetabolites, Antineoplastic↗
PubMed2003

Possible chemoresistance-related genes for gastric cancer detected by cDNA microarray.

To identify chemoresistance-related genes of gastric cancer, we utilized cDNA microarray technology. Thirty-five gastric cancer specimens surgically resected at our institute between 1998 and 1999 were studied for quantification of expression of 6300 genes by means of oligonucleotide microarray methods, and the results were evaluated in comparison with the chemoresistance of the specimens, which was determined by MTT (tetrazolium-based 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Inhibition rates (IR) were determined for cisplatin (DDP), 5-fluorouracil (5-FU), mitomycin C or doxorubicin. IR of 60% or more was regarded as sensitive to each agent, and IR of less than 40% was defined as resistant. Clustering was successfully completed for DDP, resulting in selection of 23 candidates as DDP-resistance-related genes, including vascular permeability factor, 2 membrane transporting subunits, and retinoblastoma-binding protein-1. In addition, further selection of DDP-resistance-related genes was performed according to these criteria: 1) Expression of the gene can be detected in more than 70% of resistant tumors. 2) Expression can be detected in less than 30% of sensitive tumors. 3) Expression in tumors is more than twice that of normal mucosa in more than 50% of specimens. Then, metallothionein-IG and heparin-binding epidermal growth factor-like growth factor (HB-EGF) were identified as candidate DDP-resistance-related genes. When known DDP-resistance-related genes were analyzed according to the MTT assay result, families of glutathione-S-transferase and cyclooxygenase-2 genes were also evaluated as resistance-related genes. For 5-FU resistance, dihydropyrimidine dehydrogenase and HB-EGF-like growth factor genes were also suggested to be resistance-related genes. The present study demonstrated that oligonucleotide microarrays can provide information regarding chemoresistance factors in cancer.

Antineoplastic Agents↗
PubMed2003

Gene expression in colorectal cancer and in vitro chemosensitivity to 5-fluorouracil: a study of 88 surgical specimens.

To predict the sensitivity of colorectal cancer to 5-fluorouracil (5-FU), we compared the gene expression of surgically obtained colorectal cancer specimens with chemosensitivity to 5-FU as detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. Eighty-eight patients with advanced and/or metastatic colorectal cancer provided written informed consent and entered the trial from September 2000 to October 2001. Fresh surgical specimens were used for the MTT assay, and sensitivity to 5-FU was evaluated at a cutoff concentration of 50 microg/ml and 48-h incubation time. Frozen samples were stored at - 80 degrees C until mRNA analysis of thymidylate synthetase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), es-nucleoside transporter (NT), and E2F1 by real-time RT-PCR. The correlations between the variables were analyzed, and the predictive value of these mRNAs was assessed statistically using a receiver operating characteristic (ROC) curve. NT and DPD, TP and DPD, and TP and NT mRNA expression levels correlated significantly, while TS and E2F1 showed no correlations. High NT expression was associated with low sensitivity to 5-FU (P < 0.013), as were high DPD and E2F1 expression (P < 0.022 for both). High TP mRNA expression correlated with low sensitivity to 5-FU (P < 0.034), although high TS mRNA expression did not. ROC curves indicated that DPD and NT mRNAs were possible predictors of sensitivity to 5-FU, with cutoff values of 0.6 and 0.4, respectively. The sensitivity of colorectal cancer to 5-FU may be regulated by DPD, the rate-limiting enzyme of catabolism, and NT, an important transmembrane transporter of nucleosides.

Antimetabolites, Antineoplastic↗
PubMed2002

Significance of transforming growth factor beta1 as a new tumor marker for colorectal cancer.

Transforming growth factor beta1 (TGF-beta1) is thought to be involved in cancer growth and progression. TGF-beta1 changes to its active form after being secreted in its latent form. Our aim was to clarify the significance of plasma concentrations of active and total TGF-beta1 of patients with colorectal cancer. Plasma concentrations of active and total TGF-beta1 in 45 patients with colorectal cancer and 23 healthy volunteers were measured using ELISA and the activation rate (ratio of active to total TGF-beta1) was determined. Plasma concentrations of active TGF-beta1 (21.9 +/- 12.8 pg/ml) were significantly higher in patients with colorectal cancer than in healthy volunteers (9.9 +/- 5.9 pg/ml; p < 0.001, Welch's t-test). Concentration of total TGF-beta1 was also significantly higher for patients with colorectal cancer (18.0 +/- 13.0 ng/ml vs. 11.1 +/- 6.4 ng/ml; p < 0.01, Welch's t-test). However, there was no significant difference in the TGF-beta1 activation rate between the 2 groups. There was a correlation between Dukes' stage and plasma concentration of active or total TGF-beta1 (p < 0.01, Spearman's rank correlation test) and on day 7 the active TGF-beta1 levels for patients recovering from curative resection were similar to those of the control group of healthy volunteers. These results suggest that active TGF-beta1 might be used as a tumor marker for colorectal cancer.

Adenocarcinoma↗
PubMed2002

UCN-01 (7-hydroxystaurosporine) inhibits the growth of human breast cancer xenografts through disruption of signal transduction.

BACKGROUND: 7-Hydroxystaurosporine (UCN-01), originally isolated as a phospholipid-dependent protein kinase C inhibitor, has been shown to have antitumor activity against several human cancer cell lines. UCN-01 inhibits cell cycle progression from the G1 to S phase by inhibition of cyclin-dependent kinase (CDK) activity and induction of intrinsic CDK inhibitor protein, leading to dephosphorylation of retinoblastoma (Rb) protein. MATERIALS AND METHODS: The antitumor activity of UCN-01 has been investigated against three human breast carcinoma strains serially transplanted into nude mice, including estrogen-dependent MCF-7, Br-10, and estrogen-independent MX-1. When the inoculated tumors started growing exponentially, UCN-01 (7.5 mg/kg) was administered intraperitoneally on five consecutive days a week for 2 weeks. The antitumor effect was evaluated as the lowest T/C ratio (%) during the experiments, where T was the relative mean tumor weight of the treated group and C was that of the control group. At the end of UCN-01 administration expression of p21, a protein of the CDK inhibitor family, and phosphorylated and dephosphorylated Rb protein was detected by Western blotting using treated and control tumors. RESULTS: UCN-01 had activity against MCF-7 and Br-10, with the lowest T/C ratios of 25.0% and 27.0%, respectively, while MX-1 was resistant to UCN-01 with a T/C ratio of 65.9%. The antitumor spectrum of UCN-01 was different from that of other conventional agents such as doxorubicin and cyclophosphamide which were ineffective against Br-10 but were active against MX-1. Although p21 was induced in three tested strains by UCN-01, little dephosphorylated Rb protein was expressed in MX-1 compared with Br-10 and MCF-7 (in vitro). CONCLUSION: UCN-01 appeared to be a promising agent for the treatment of breast cancer, with a different mode of action and antitumor spectrum from other currently available antitumor drugs.

Alkaloids↗
PubMed2002

Rare case of early mucosal gastric cancer presenting with metastasis to the bulbar conjunctiva.

Early gastric cancer has an excellent outcome following surgical treatment. In particular, mucosal gastric cancer (m-cancer) very rarely results in metastatic dissemination and may be successfully treated by local surgical resection. We report a 64-year-old Japanese woman who presented with a recurrent cystic lesion on the left bulbar conjunctiva, with a biopsy specimen revealing metastatic signet-ring cell carcinoma. Gastrointestinal investigations revealed an early gastric cancer in the lesser curvature of the stomach. Biopsy specimen of the gastric lesion indicated poorly differentiated adenocarcinoma, which was identical to findings in the lesion in the bulbar conjunctiva. She underwent a distal gastrectomy and made an uneventful recovery. Histopathological analysis indicated a gastric signet-ring cell carcinoma that was limited to the mucosal layer, without evidence of lymphatic spread. Although the exact mechanism of metastatic dissemination to the bulbar conjunctiva is unclear, this case is very unusual, because ocular metastases almost invariably occur in the context of documented and established malignant disease. This is, to our knowledge, the first reported case of a patient with gastric mucosal cancer who presented with a conjunctival metastatic deposit and who subsequently received curative surgical treatment for both conditions.

Adenocarcinoma↗
PubMed2002

Cyclooxygenase-2 expression as a new marker for patients with colorectal cancer.

PURPOSE: Epidemiologic studies indicate that the use of nonsteroidal anti-inflammatory drugs, which inhibit cyclooxygenase activity, reduce the risk of colorectal cancer. In addition, several studies demonstrate increased expression of cyclooxygenase-2 in human colorectal cancer tissues. However, the role of cyclooxygenase-2 expression in colorectal cancer has not yet been fully established. The aim of this study was to clarify the clinicopathologic significance of cyclooxygenase-2 expression in human colorectal cancer. METHODS: A total of 232 surgically resected colorectal cancer specimens were analyzed immunohistochemically with the use of a murine anti-human cyclooxygenase-2 monoclonal antibody. Cyclooxygenase-2 expression was then compared with clinicopathologic background and survival outcome. RESULTS: Cyclooxygenase-2 was expressed in the cytoplasm of the cancer cells but not in normal epithelium. Cyclooxygenase-2 expression was noted in 71.6 percent (166/232) of the cancer patients and correlated significantly with histologic type (P = 0.033), depth of invasion (P = 0.016), pathologic stage (P = 0.020), and metachronous liver metastasis (P = 0.001). Multivariate analysis for factors associated with metachronous liver metastasis showed that cyclooxygenase-2 expression was one of the independent risk factors, second only to lymph node metastasis. Patients with cyclooxygenase-2 expression showed a significantly poorer outcome compared with those without cyclooxygenase-2 expression (P = 0.002). CONCLUSION: Cyclooxygenase-2 expression in the primary lesion may be a useful marker for evaluating prognosis and liver metastasis in patients with colorectal cancer.

Aged↗
PubMed2002

Minimally invasive surgery for gastric carcinoid tumor.

Minimally invasive laparoscopic wedge resection for gastric mucosal carcinoma and submucosal tumor was first performed in Keio University hospital in 1992. Since then, 172 gastric tumor patients, including four cases of carcinoid tumor, have been successfully treated at the Keio University hospital using this procedure. No local disease recurrence or distant metastases have been observed in follow-ups over as long as 10 years. Chronic atrophic gastritis patients with carcinoid tumors occurring secondary to hypergastrinemia are candidates for the minimally invasive surgery. With careful patient selection according to tumor size, depth of invasion, and histopathological findings of malignancy grade, endoscopic and laparoscopic therapy for these patients can be a safe, curative, and minimally invasive procedure.

Carcinoid Tumor↗
PubMed2002

Intraoperative lymphatic mapping and sentinel lymph node sampling in esophageal and gastric cancer.

Recent studies for SN mapping of esophageal and gastric carcinoma show that the SN concept is valid even for upper GI cancers with multidirectional and complicated lymphatic flow. The relatively high incidence of anatomic skip metastasis can be attributed to aberrant distribution of SNs. An individualized and minimally invasive surgical approach can be applicable to management of esophageal and gastric carcinoma based on SN status. Although there are several issues to be resolved, this novel procedure has the potential for great benefit to improve quality control in the treatment of upper GI cancer. Well-designed clinical trials of lymphatic mapping for upper GI cancer will be essential to determine whether this technique is widely applicable in the management of these tumors.

Esophageal Neoplasms↗
PubMed2002

In situ cancer vaccination with a replication-conditional HSV for the treatment of liver metastasis of colon cancer.

In this study, we investigated the therapeutic efficacy of a replication-conditional mutant HSV, G207, for the treatment of liver metastasis of colon carcinoma. Three liver metastasis models in syngeneic BALB/c mice were developed: (i) splenic injection, (ii) splenic and subcutaneous (s.c.) injection, and (iii) orthotopic implantation of CT26 colon carcinoma. In the splenic injection model, G207 was injected into the established splenic tumor on day 7. In the splenic and s.c. injection model, G207 were injected into the established s.c. tumor on days 5 and 8. In the orthotopic implantation model, a piece of CT26 tumor tissue was transplanted onto the wall of the cecum and G207 was injected in the established cecum tumor on day 7. On day 21 or 28, animals were sacrificed and liver metastases were evaluated. In all three models in immunocompetent mice, liver metastases were significantly reduced by intratumoral inoculation with G207 compared to the control. In athymic mice, however, there was no significant therapeutic effect of intratumoral inoculation with G207 on liver metastases. Tumor-specific cytotoxic T-lymphocyte responses were induced in mice treated with G207 in the orthotopic implantation model. These results suggest that intratumoral inoculation of G207, as an in situ cancer vaccine, can be an effective approach against liver metastasis of colon cancer and the efficacy involves tumor-specific T-cell responses.

Animals↗
PubMed2002

Matrix metalloproteinase inhibitor, marimastat, decreases peritoneal spread of gastric carcinoma in nude mice.

Marimastat, a matrix metalloproteinese inhibitor, was examined for the ability to prevent peritoneal dissemination of a human gastric cancer xenograft, TMK-1. Even with novel approaches such as molecular targeting of cancer chemotherapy, peritoneal dissemination of gastric cancer has little sensitivity to anticancer drugs, and it is impossible to inhibit its growth completely. Intraperitoneal injection of TMK-1 into nude mice at 5 x 10( 5) cells / body resulted in carcinomatous peritonitis that mimicked clinical cases. Continuous administration of marimastat (18 mg / kg / day) from 24 h after the tumor inoculation successfully inhibited the growth of peritoneal dissemination nodules. Combined administration of marimastat (18 mg / kg / day) and mitomycin C (MMC, 2 mg / kg) showed synergistic inhibition of growth of peritoneal dissemination, being superior to MMC alone (2 mg / kg). Although marimastat alone could not increase survival time with statistical significance, combined administration of marimastat and MMC had a survival benefit with statistical significance. The combination of marimastat and MMC increased the preventive effect on peritoneal dissemination. Marimastat seems to be a candidate for the prevention of peritoneal spread of gastric carcinoma.

Animals↗
PubMed2002

Arteriovenous shunting blood flow is intravitally observed in the stomach after thermal injury in rats.

Microcirculatory disturbance of the gastric wall is a crucial factor in the development of gastric mucosal lesions induced by Helicobacter pylori, anti-inflammatory drugs and stress. Opening of the arteriovenous shunting channel after thermal injury is one of the possible mechanisms to reduce mucosal blood flow. However, no in vivo observation of arteriovenous shunting blood flow in the stomach has been reported. To assess gastric microcirculatory disturbance, especially arteriovenous shunting blood flow after thermal injury by in vivo microsciopy, male Wistar rats were anesthetized and thermal injury was inflicted on the back skin. Gastric microvascular images were observed by in vivo microscopy. Rolling of leukocytes labelled with carboxyfluorescein diacetate, succinimidyl ester were counted and blood flow dynamics were observed by flow of a micro dye, monastral blue B (MBB). The endothelial damage was assessed by deposits of MBB 5 min after the administration. Arteriovenous shunting blood flow is difficult to detect by normal methods, but it could be observed by How of MBB after thermal injury. Statistical analysis showed a significant difference in the ratio of arteriovenous shunting blood flow detection between the control (no injury) (0%; n = 15) and thermal injury (5 hrs after thermal injury) (28.6%; n = 14) groups. In the thermal injury group, the percentage of rolling leukocytes and the area of monastral blue B deposits increased, and the venular walls tended to be irregular. The total length of erosion increased time-dependently after thermal injury, and the length at 5 hrs was approximately 2 times larger than that at 2 hrs. Arteriovenous shunting blood flow is intravitally observed after thermal injury. A-V shunting blood flow can be a cause of mucosal hypoperfusion. It is suggested that the microcirculatory disturbance seen 5 hrs after thermal injury is contributed to the final step of erosion formation.

Animals↗
PubMed2002

[A novel combined chemotherapy using TS-1 and low-dose cisplatin against liver metastasis of gastric cancer].

We used a novel combination chemotherapy of TS-1 and low-dose cisplatin (CDDP) with 4 gastric cancer patients with liver metastases (one far advanced and 3 recurrent patients). TS-1 was administered at 80 mg-120 mg/body/day, twice daily for 3 weeks followed by a 2-week interval as one cycle, and CDDP was administered at 6 mg/m2/day div, for 5 days followed by a 2-day interval (1 cycle for an inpatient) or at 6 mg/m2/day div, at 5 times for 2-3 weeks (1 cycle for an outpatient). Efficacy and toxicity were evaluated after 3-6 cycles of the regimen, as long as the patients tolerated the regimen without severe side effects. This regimen resulted in 1 complete response, 2 partial responses and 1 progressive disease, showing a 75% efficacy rate. One patient experienced grade 2 nausea from this regimen, which was ameliorated by means of prolonging the interval of CDDP-administration. Thus, the regimen is useful to maintain patients' quality of life without severe adverse effects, and has a high efficacy in gastric cancer patients with liver metastases.

Administration, Oral↗
PubMed2000

Surgically treated Cronkhite-Canada syndrome associated with gastric cancer.

Cronkhite-Canada syndrome is generally accepted to be a benign disorder, with 374 reported cases to the present. Worldwide, there have been 18 previously reported cases of Cronkhite-Canada syndrome associated with gastric cancer. In this report we describe a case of a 52-year-old man with the clinical features of Cronkhite-Canada syndrome combined with gastric cancer. Although the gastric tumor was located at the antrum of the stomach, we performed a total gastrectomy because of the edematous swelling and high risk of malignancy in the remnant stomach. As Cronkhite-Canada syndrome may be a premalignant condition for gastric cancer, as well as for colorectal cancer, we suggest periodic examination of the stomach, colon, and rectum for patients with Cronkhite-Canada syndrome.

Journal Article↗