Biomedical subjects

Kei Ukon

Publications and source records attributed to Kei Ukon.

10 recordsLinked to original sources

PubMed2007

Neutrophil elastase induces cell proliferation and migration by the release of TGF-alpha, PDGF and VEGF in esophageal cell lines.

Rapid regrowth or recurrent growth of occult cancer cells are often observed after esophagectomy or postoperative complications. In order to clarify the mechanism of such oncological circumstances, we focused on neutrophil elastase (NE), which degrades a broad spectrum of extracellular matrix and cell surface proteins. In the present study, we demonstrated that NE stimulated the growth of all of the five esophageal cell lines (TE-1, -7, -8, -12 and -13) by MTT assay and promoted cell invasion by cell migration assay. Pro-transforming growth factor-alpha (pro-TGF-alpha) from the cell membrane was released to the culture medium as a mature form after treatment with 5 microg/ml NE, and it reached the maximum level of 153% compared to the control values at 15 min of treatment in TE-13 cells. The phosphorylation of epidermal growth factor receptor (EGFR) rapidly occurs after treatment with NE and triggered the extracellular signal-regulated kinases 1 and 2 (ERK) signaling pathway. Moreover, NE induced release of platelet-derived growth factor-AA (PDGF-AA), PDGF-BB and vascular endothelial growth factor (VEGF) to 141.9, 227.7, and 171.6% of the control values, respectively. A specific NE inhibitor, sivelestat, significantly inhibited the NE-induced cell proliferation, cell invasion and subsequently inhibited the signal transduction pathway. Furthermore, sivelestat significantly inhibited NE-induced release of TGF-alpha, PDGF-AA, PDGF-BB and VEGF in the medium in TE-13 esophageal carcinoma cells. These results strongly indicate that NE released from activated neutrophils stimulates the growth and progression of esophageal cancer cells by releasing the growth factors on the cell surface and that sivelestat, a specific NE inhibitor, blocks these processes. Furthermore, we postulate that postoperative administration of sivelestat might be useful as a new molecular-targeting cancer therapy as well as for the treatment of postoperative respiratory complications.

Cell Growth Processes↗

PubMed2006

Sivelestat, a specific neutrophil elastase inhibitor, suppresses the growth of gastric carcinoma cells by preventing the release of transforming growth factor-alpha.

Neutrophil elastase is a neutral serine proteinase produced by polymorphonuclear leukocytes and monocytes/macrophages, especially under surgical stress. In the present study, we investigated whether NE promotes cell growth by activation of EGFR to elucidate whether surgical stress induces tumor proliferation and progression. Furthermore, we examined the antitumor effect of a specific NE inhibitor, sivelestat. Cell growth assays were carried out in vitro and in vivo using TMK-1 gastric cancer cells. TMK-1 cell growth was stimulated to 118% of that of the control cells after 48 h stimulation with 1 microg/mL NE according to an MTT assay. Sivelestat inhibited cell growth to 23.4 and 58.0% of control values at concentrations of 100 and 1,000 microg/mL, respectively. NE rapidly phosphorylated EGFR in only 5 min and triggered the ERK1/2-mitogenic signaling pathway in TMK-1. It was further demonstrated that NE-induced EGFR phosphorylation was transactivated through TGF-alpha, using ELISA. NE increased the cleavage of TGF-alpha from the cell surface 30-fold compared with the cells without treatment. Interestingly, sivelestat significantly reduced NE-induced EGFR phosphorylation and ERK1/2 activation and completely blocked the release of TGF-alpha from the TMK-1 cell surface. In a xenograft study, the addition of ventrotomy as a surgical stress promoted tumor growth. Sivelestat significantly suppressed the tumor growth induced by surgical stress. These results indicate that sivelestat suppresses the growth of gastric cancer cells by inhibiting the release of TGF-alpha stimulated by NE, which often occurs after surgical stresses.

Animals↗

PubMed2006

Synergistic effects of docetaxel and S-1 by modulating the expression of metabolic enzymes of 5-fluorouracil in human gastric cancer cell lines.

We have recently demonstrated in a Phase I/II study that combination chemotherapy with docetaxel (TXT) and S-1 is active against metastatic gastric carcinomas. To elucidate the mechanisms underlying the synergistic effects of these drugs, both the growth inhibitory effects and the expression profiles of enzymes involved in fluorouracil (5-FU) metabolism were examined in vitro and in vivo. TXT alone and in combination with 5-FU inhibited the growth of each of the 5 gastric cancer cell lines that we examined (TMK-1, and MKN-1, -28, -45 and -74), in a time- and dose-dependent manner. Moreover, striking synergistic effects were observed in TMK-1 cells in vitro with IC50 values of between 4.73 and 0.61 nM 5-FU. Furthermore, in TMK-1 xenografts, 5-FU/TXT cotreatments exhibited synergistic antitumor effects. The combination of S-1 and TXT, however, exhibited greater growth-inhibitory effects than the 5-FU/TXT cotreatments. The mechanisms underlying these synergistic effects of S-1 and TXT were examined by expression and activity analyses of the 5-FU metabolic enzymes. The expression of thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD) were decreased 50 and 73% of control levels, respectively, and that of orotate phosphorybosyl transferase (OPRT) was increased by 3.9-fold at the protein level. These findings suggested that biochemical modulation of the 2 drugs had occurred, which was further confirmed by the results of the activity assays. These data strongly indicate that a combination chemotherapy of TXT and S-1 is effective against gastric carcinomas and is therefore a good candidate as a standard chemotherapeutic strategy in treating these tumors.

Animals↗

PubMed2006

[Combination chemotherapy of S-1 and docetaxel on advanced and recurrent gastric cancer].

In the present article, we have summarized the phase I/II clinical trials on combination therapy of S-1 and docetaxel. With result of the phase I study, patients were treated with intravenous infusion of 40 mg/m2 docetaxel on day 1 and oral S-1 80 mg/m2/day on days 1 to 14 every 3 weeks. Forty eight patients received a total of 272 treatment cycles. No complete responses (CRs) and 27 partial responses (PRs) were observed for an overall response rate (CR+PR) of 56.2% (95% CI, 38-66%). Eighteen patients (37.5%) had stable disease (SD), and 3 patients (6.2%) had progressive disease (PD) as best response. The tumor control rate (CR+PR+SD) was 93.8% (95% CI, 83-98%). The median overall survival was 14.3 months (95% CI: 10.7-20.3 months) and the median time to tumor progression was 7.3 months (95% CI: 4.2-10.7 months). The most common grade 3-4 hematologic toxicities were neutropenia 58.3%, leukopenia 41.7%, febrile neutropenia 8.3%, and anemia 8.3%. The most common grade 3 nonhematologic toxicities were anorexia 14.6%, stomatitis 8.3%, nausea 6.3%, diarrhea 4.2%, constipation 4.2%, and vomiting 2.1%. No grade 4 nonhematologic toxicities were reported, and all treatment-related toxicities were resolved. The mechanisms underlying these synergistic effects of S-1 and docetaxel were examined by expression and activity analyses of 5-FU metabolic enzymes. The expressions of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) were decreased and that of orotate phosphorybosyl transferase (OPRT) was increased in mRNA, protein level and activity assay after the treatment with docetaxel and 5-FU in the TMK-1 gastric cancer cell. These findings strongly indicate that the combination chemotherapy of docetaxel and S-1 is effective against gastric carcinomas and therefore is a good candidate as a standard chemotherapeutic strategy in treating these tumors.

Adult↗

PubMed2005

Activator protein accelerates dihydropyrimidine dehydrogenase gene transcription in cancer cells.

Dihydropyrimidine dehydrogenase is the most extensively investigated predictive marker for individual response to 5-fluorouracil. Clinical responses to the anticancer agent, along with various reports, have clearly shown that dihydropyrimidine dehydrogenase activity is closely correlated to its mRNA levels, but the regulatory mechanisms of its expression have remained unclear. We attempted to clarify the mechanisms and found that activator protein (AP-1) is probably one of the key factors in the transcriptional regulation of DPYD in cancer cells, and that phorbol 12-myristate 13-acetate (PMA) plus ionomycin treatment enhances transcription of DPYD via AP-1 activation. In this study, we characterized our previously subcloned 5' region of human DPYD, an approximately 3.0-kb fragment (accession no. AB162145). Luciferase reporter assay showed that the clone showed strong promoter activities in 293T and HSC42 cells, and comparative analysis using 5' deletion mutants suggested the existence of several positive and negative regulatory regions, including putative binding sites for AP-1, SP-1, and nuclear factor-kappaB. PMA/ionomycin treatment increased the mRNA level of DPYD in HSC42 cells, and electrophoretic gel mobility shift assay showed that the complex on the putative AP-1 binding site was drastically induced by PMA/ionomycin treatment. The complexes formed were competed out by preincubation with the cold-consensus AP-1 binding site, and the DNA binding complex formed on the site contained c-Jun and c-Fos, which are components of AP-1 transcription factor. We further identified the functional AP-1 binding site (nucleotide positions from -290 to -280), whose nucleotide mutations abolished PMA/ionomycin-induced DPYD promoter activation.

Binding Sites↗

PubMed2005

[A case of remnant gastric cancer with multiple bone metastasis and peritoneal dissemination; efficacy of combination therapy of docetaxel and TS-1].

A 69-year-old female underwent radical surgery for advanced gastric cancer (Stage IIIA) 7 years ago. She was diagnosed as remnant gastric cancer with multiple bone metastasis and peritoneal dissemination. Treatment with docetaxel and TS-1 was started with the following regimen: daily oral administration of 100 mg/body TS-1 for 14 days, followed by a 7 day rest and infusion of 40 mg/m2 docetaxel on day 1. Two months after the initial administration of docetaxel/TS-1, the sites of the remnant gastric cancer and bone metastasis were reduced in size, and the ALP returned to almost the normal level. The site of peritoneal dissemination had disappeared. Currently (nine months after diagnosis), she is undergoing therapy with TS-1. The combination of docetaxel and TS-1 can be a new tool for the management of gastric cancer with bone metastasis.

Adenocarcinoma↗

PubMed2005

[Clinical study of TS-1 for inoperative and recurrent gastric cancer and evaluation of long survival cases].

The clinical efficacy and safety of TS-1 therapy were studied retrospectively in patients with inoperable and recurrent gastric cancer. The subjects were 67 patients who were treated with TS-1 in our department between June 1999 and September 2004. The objective overall response rate was 41.0% (16/39; 95% confidence interval, CI, 25.3-56.7). By location, the response rate of peritoneal dissemination was high (57.1%), as were those of primary lesion (53.3%) and lymph nodes (42.9%). The prevalence of adverse reactions with a grade of 3 or 4 was 12.8%. The median survival rate (MST) was 276 days with 1-year and 2-year survival rates of 48.9% and 27.8%, respectively. This resulted in 6 long-term survival cases (over 2.5 years) after TS-1 therapy, and the longest survival time was 3y 5m after TS-1 therapy. PRs or long-term NCs after TS-1 therapy were likely to be important factors for long-term survival. In conclusion, TS-1 is safe and effective for patients with inoperable and recurrent gastric cancer, and is promising as a first-line treatment.

Adult↗

PubMed2004

Aberrant methylation of DPYD promoter, DPYD expression, and cellular sensitivity to 5-fluorouracil in cancer cells.

PURPOSE: Dihydropyrimidine dehydrogenase (DPD), the initial rate-limiting enzyme in the degradation of 5-fluorouracil (5-FU), is known to be a principal factor in clinical responses to the anticancer agent 5-FU, and various reports have clearly demonstrated that DPD activity is closely correlated to mRNA levels. However, the regulatory mechanisms of DPD gene (DPYD) expression remain unclear. In this study, the regulatory mechanisms have been intensively studied. EXPERIMENTAL DESIGN AND RESULTS: A subcloned 3.0-kb fragment of the 5' region of DPYD contains a total of 60 CpG sites, suggesting that methylation status may affect the repression of DPYD. The clone showed various promoter activities that were largely correlated with mRNA levels in most cell lines, except HSC3 and HepG2. Bisulfite sequencing analysis revealed that various CpG sites around the transcription start site were abnormally methylated in cells with low DPYD expression: Reversal of hypermethylation by 5-azacytidine treatment significantly increased DPYD expression in HSC3 and HepG2 cells that showed strong promoter activity. In HepG2, in vitro methylation of the DPYD promoter directly decreased promoter activity, and 5-azacytidine treatment restored higher DPYD expression in a dose- and time-dependent manner, along with decreased sensitivity to 5-FU. CONCLUSIONS: We found that DPD activity was controlled, at least in part, at the transcription level of DPYD and that aberrant methylation of the DPYD promoter region acted as one of the repressors of DPYD expression and affected sensitivity to 5-FU in cancer cells. Our new results could lead to a more precise understanding of the molecular basis of 5-FU response.

Adenocarcinoma↗

PubMed2003

Hypoxia-inducible factor-1alpha polymorphisms associated with enhanced transactivation capacity, implying clinical significance.

Hypoxia-inducible factor-1 (HIF-1) is a pivotal factor that regulates cellular responses to hypoxia and is presumably linked to regulation of angiogenesis and tumor growth. We assessed the difference in transcription activity of two HIF-1alpha polymorphic variants (P582S and A588T), along with molecular epidemiological study among head and neck squamous cell carcinoma (HNSCC) patients. Both HIF-1alpha variants revealed significantly higher transcription activity than wild-type (WT) did, under normoxic and hypoxic conditions (P < 0.02). Furthermore, tumors from HNSCC patients with heterozygous alleles having P582S or A588T had significantly increased numbers of microvessels compared with those with homozygous WT (P = 0.02). In addition, all patients with tumors of T1 (below 2 cm diameter) were WT, while 14 of 47 patients with tumors of > or =T2 were heterozygous. The elevated transactivation capacity of variant forms of HIF-1alpha implies a role of HIF-1alpha polymorphisms in generating individually different tumor progression.

Amino Acid Sequence↗

PubMed2002

Cellular sensitivity determinants to docetaxel in human gastrointestinal cancers.

beta-tubulin (beta-TUB), Bcl-XL, and additionally glutathione S-transferase pi (GSTpi) were found to participate in sensitivity to docetaxel (TXT) in 7 human gastrointestinal cancer cell lines. The gene expression level of beta-TUB, Bcl-XL, and GSTpi was closely correlated with the IC50 for TXT. beta-TUB amount related to TXT resistance, and GST activity was correlated with IC50 for TXT in the 30-min treatment setting. Bcl-XL transfection increased TXT resistance of COLO201 cells, whereas GST inhibition by ethacrynic acid enhanced TXT cytotoxicity. Continuous TXT treatment increased beta-TUB and GSTpi expression, but the increased GSTpi mRNA was observed in TXT-resistant HCC-48 cells alone.

Cell Division↗