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Biomedical subjects

M Kuwano

Publications and source records attributed to M Kuwano.

At least 91 records · Page 5Linked to original sources
PubMed1998

Clinical significance of the increased multidrug resistance-associated protein (MRP) gene expression in patients with primary breast cancer.

The efficacy of cancer treatment is limited by either intrinsic or acquired resistance to various chemotherapeutic agents. To evaluate the clinically important factors related to prognosis in primary breast cancer retrospectively, we investigated the expression of the following genes involving acquirement of drug resistance: multidrug resistance 1 (MDRl), multidrug resistance-associated protein (MRP), and topoisomerase (Topo) I, II alpha, and II beta. Using an RT-PCR method, we semiquantified the gene expression level in untreated stage II breast cancer tissue (n = 27) and noncancerous breast tissue (n = 10). Among the 27 cancer patients, who were all treated by adjuvant chemoendocrine therapy after surgery, 10 patients showed relapse within the following 10 years whereas 17 patients did not. The gene expression levels of MDRl, MRP, and Topo I, II alpha, and II beta were normalized to the level of the beta 2-microglobulin RT-PCR product. MRP mRNA expression was detected in 70% of the breast cancer tissues and its expression levels were significantly increased in the cancer group compared with the noncancerous breast tissues. Furthermore, the MRP level was much higher in the relapsed patient group. On the other hand, there were no significant differences in the MDRl mRNA levels between the noncancerous and cancer groups. Although Topo II alpha mRNA was not detected in noncancerous breast tissues, it was detected in 52% of the breast cancer tissues. In cancer patients, no significant difference in Topo II alpha mRNA levels was observed between the relapsed and nonrelapsed groups. These findings suggest that MRP might be used as one of the markers for poor prognosis in patients with breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Nuclear expression of YB-1 protein correlates with P-glycoprotein expression in human osteosarcoma.

The Y-box-binding protein, YB-1, is a member of the DNA-binding protein family. It binds to the Y-box, an inverted CCAAT box, in the promoter region of the human multidrug resistance 1 gene, which encodes P-glycoprotein (P-gp). Nuclear localization of YB-1 protein has been reported to be associated with the intrinsic expression of P-gp in human breast cancer. We studied the immunohistochemical expression of YB-1 protein in 69 untreated biopsy specimens of conventional osteosarcomas and compared it with the expression of P-gp. Furthermore, cell proliferation, as determined by the MIB-1-labeling index (MIB-1-LI), was measured by immunohistochemistry. In all 69 untreated osteosarcomas, YB-1 protein was expressed in the cytoplasm. In 32 of 69 (46%) cases, YB-1 was also localized in the nucleus. The expression of P-gp was evident in 23 of these 32 cases, and there was a significant correlation between the nuclear expression of YB-1 and P-gp expression (P < 0.0001). Chondroblastic osteosarcoma expressed YB-1 in the nucleus more frequently (eight of nine cases) than did other types of osteosarcoma, whereas P-gp was also frequently expressed in chondroblastic subtype. There was no correlation between the nuclear expression of YB-1 and histological grade. The MIB-1-LI was significantly higher in cases showing the nuclear expression of YB-1 (MIB-1-LI averaged 22.56 in cases with only cytoplasmic expression of YB-1 but averaged 28.20 in cases with cytoplasmic and nuclear expression of YB-1; P = 0.0477). In human osteosarcoma, nuclear localization of YB-1 protein was associated with the expression of P-gp, suggesting that YB-1 could be a prognostic marker for multidrug resistance in osteosarcoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

A canalicular multispecific organic anion transporter (cMOAT) antisense cDNA enhances drug sensitivity in human hepatic cancer cells.

The human cMOAT gene encodes a membrane protein involved in the ATP-dependent transport of hydrophobic compounds. To determine whether cMOAT is associated with drug sensitivity, we transfected an expression vector containing cMOAT antisense cDNA into the HepG2 human hepatic cancer cell line. We observed a reduction in cMOAT protein, as well as an enhanced level of glutathione, in the antisense transfectants. The transfectants displayed an increased sensitivity to cisplatin, vincristine, doxorubicin, and the camptothecin derivatives, (4S)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino)carbonyl oxy]dione hydrochloride triethydrate and 7-ethyl-10-hydroxycamptothecin, but not to etoposide, 3-[4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitrosoure a, 5-fluorouracil, and mitomycin C. Results suggest that cMOAT levels are inversely correlated with those of glutathione, and that cMOAT and its related genes may be involved in the sensitivity of cells to certain anticancer agents.

ATP-Binding Cassette Transporters↗
PubMed1997

Stimulation of cell-surface urokinase-type plasminogen activator activity and cell migration in vascular endothelial cells by a novel hexapeptide analogue of neurotensin.

To investigate if neurotensin (NT) could induce activation of urokinase-type plasminogen activator (uPA) in vascular endothelial cells, we utilized the acetyl-NT (8-13) analogue, TJN-950, in which the C-terminal leucine is reduced to leucinol. TJN-950 inhibited the binding of 125I-NT to membranes of newborn rat brains and of COS-7 cells transfected with rat NT receptor cDNA, but at 10(4) higher doses than NT (8-13). However, TJN-950 was as effective as NT in inducing the fibrinolytic activity in bovine vascular aortic and human umbilical vein endothelial cells, and enhanced the migration of vascular endothelial cells. Moreover, administration of TJN-950 induced neovascularization in the rat cornea in vivo. TJN-950 had no effect on expression of uPA, plasminogen activator inhibitor-1 or uPA receptor mRNA. The binding of 125I-TJN-950 to cell membranes was blocked by unlabeled uPA and TJN-950, but not the amino-terminal or 12-32 fragment of uPA. TJN-950 may enhance uPA activity in vascular endothelial cells by interacting with the uPA receptor, resulting in induction of angiogenesis.

Animals↗
PubMed1997

Human canalicular multispecific organic anion transporter (cMOAT) is expressed in human lung, gastric, and colorectal cancer cells.

Human canalicular multispecific organic anion transporter (cMOAT), a glutathione conjugate membrane transporter, has been isolated from cisplatin-resistant cancer cells and is distributed mainly in normal liver. We analyzed the expression of human cMOAT in 14 lung, 11 gastric, and 9 colorectal non-drug-selected human cancer cells, two multidrug-resistant cells, and one cisplatin-resistant cells, using quantitative RT-PCR and newly developed anti-human cMOAT antibody. All cell lines analyzed here expressed human cMOAT at the level of mRNA and protein, and some of them expressed higher levels of human cMOAT than the cisplatin-resistant cells. The two multidrug-resistant cell lines co-expressed human cMOAT gene and both or either of MRP and MDR1 genes. Immunostaining showed that human cMOAT was predominantly localized to the cytoplasm of these single cells. Our results indicate that human cMOAT is expressed in various human cancer cells including drug-resistant cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Nuclear translocation of the Y-box binding protein by ultraviolet irradiation.

The Y-box binding protein, YB-1, is a member of a DNA binding protein family with a structurally and functionally conserved cold shock domain. Using Western blotting and immunohistochemical methods, larger amounts of YB-1 were detected in the cytosol, particularly at the perinuclear region, than in the nucleus of human cancer cells. UV irradiation increased accumulation of YB-1 in the nucleus at 20 min and thereafter. This translocation of YB-1 into the nucleus by UV irradiation was blocked by the protein kinase inhibitor H-7, but not HA-1004. Both green fluorescent protein (GFP)-YB-1 and GFP-YB-1C with the C-terminus (248-317) of YB-1 were located mainly in the cytosol, but GFP-YB-1deltaC with a deletion at the C-terminus of YB-1 was located in the nucleus. YB-1 is translocated into the nucleus by UV irradiation, possibly through a protein kinase C-mediated signal transduction pathway, and the C-terminal region of YB-1 might be important for cytoplasmic retention of YB-1.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1997

New nortriterpenoid isolated from anti-rheumatoid arthritic plant, Tripterygium wilfordii, modulates tumor growth and neovascularization.

Preparations of Tripterygium wilfordii, "Thunder God vine", have been used in China to treat rheumatoid arthritis. Rheumatoid arthritis, as well as solid tumors, is closely associated with neovascularization. Antiarthritic drugs therefore may modulate tumor growth as well as neovascularization. We found that a compound purified from T. wilfordii, the nortriterpenoid, demethylzeylasteral (TZ-93), inhibited the proliferation of vascular endothelial cells approximately 30 times more effectively than it did for the proliferation of human tumor cells. In in vitro assays using bovine aortic endothelial cells, TZ-93 at non-toxic doses inhibited cell migration, expression of urokinase-type plasminogen activator (uPA) mRNA and uPA activity. Exogenous addition of uPA restored the inhibitory effect of TZ-93 on cell migration. In dorsal air-sac assays in BALB/c mice, the oral administration of 3 mg/kg/day TZ-93 for 5 days partially inhibited, and 30 mg/kg/day almost completely abrogated, the development of capillary networks induced by human hepatoblastoma cells. Similarly, 0.3 mg/kg/day TZ-93 partially inhibited, and 3 or 30 mg/kg/day almost completely blocked, the growth of mouse B16-F10 melanoma cells in a tumor implantation assay. The highest dose of TZ-93 significantly reduced the growth of well-vascularized tumors with volumes of more than 500 mm3. TZ-93 treatment of tumor-bearing mice significantly decreased the density of microvessels in the tumors. We conclude that TZ-93 may be useful in treating highly vascularized and metastatic tumors as well as other angiogenic diseases.

Animals↗
PubMed1997

Maintenance of hypomethylation status and preferential expression of exogenous human MDR1/PGY1 gene in mouse L cells by YAC mediated transfer.

Selection of cells for resistance to vincristine or doxorubicin often induces overexpression of the multidrug resistance (MDR) genes, which encode the cell surface P-glycoproteins, as a result of gene amplification, transcriptional activation, or mRNA stabilization. The LMD1 and LMD4 cell lines were established after the transfer into mouse L cells of two independent yeast artificial chromosome clones containing 300 and 850 kb, respectively, of the human MDR locus. The human MDR1/PGY1 gene, but not the endogenous mouse mdr1a and mdr1b genes, was overexpressed as a result of gene amplification and transcriptional activation in various sublines of LMD1 and LMD4 cells selected for resistance to vincristine. Then we asked why human MDR1/PGY1 gene, but not mouse relevant gene, was expressed. Determination of the methylation status of cytosine residues at Msp I/Hap II cleavage sites (CCGG) in the promoter regions of human MDR1/PGY1 and mouse mdr1a revealed hypomethylation and hypermethylation of the human and mouse genes, respectively in LMD1, LMD4, and their vincristine-resistant derivatives. Various vincristine-resistant sublines were also established after exposure of LMD1 cells for 48 h to 5-aza-2'-deoxycytidine, an inhibitor of DNA methyltransferase. These sublines exhibited overexpression of mouse mdr1a and mdr1b, but not of human MDR1/PGY1, as well as hypomethylation of the mouse mdr1a promoter region. Thus, the selective expression of human or mouse MDR genes in this cell system appears to be related to the methylation status of the respective gene promoter regions.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Significance of the expression of proliferation-associated nucleolar antigen p120 in human colorectal tumors.

Nucleolar protein p120 is considered to be associated with cell proliferation and has also been detected in a broad range of human malignant cells and tissues, but not in either normal resting tissue or most benign tumors. To clarify the significance of the expression of p120 in colorectal tumors or to evaluate the contribution of p120 in the development of colorectal carcinoma, the authors developed a monoclonal antibody against p120 and then examined its expression in adenoma, carcinoma, and normal mucosa. In adenomas, p120 expression was shown in none of 13 cases of mild dysplasia (0%), 2 of 15 of moderate dysplasia (13.3%), and in 2 cases of severe dysplasia (100%). p120-positive adenomas of moderate dysplasia tended to be larger and had higher Ki-67 indexes than the negative ones (adenomas of moderate dysplasia). All 27 carcinomas were positive for p120. p120 immunostaining was found in the nuclei and corresponded closely to the prominent nucleoli of tumor cells. In contrast, either weak or the occasional expression of p120 was traced in only one of the nine normal mucosae (11.1%). Three of the transitional mucosae of the carcinoma were also positive for p120. The percentage of p120-positive tumor cells (p120 index) ranged from 3.2% to 86.6%, and the mean p120 indexes of the four adenomas and all carcinomas were 21.3% and 41.5%, respectively. The p120 index was significantly related to the Ki-67 index (P < .001) in the p120-positive tumors, whereas the p120 index of the carcinoma did not significantly correlate to the known prognostic markers, such as tumor size, stage, or the degree of differentiation. These results thus suggest that the expression of p120 serves as a marker for cells with a high proliferative potential and is linked to the late events of colorectal tumor progression.

Adenoma↗
PubMed1997

A novel brain-specific p53-target gene, BAI1, containing thrombospondin type 1 repeats inhibits experimental angiogenesis.

The genetic alteration of p53 is associated with neovascularization during progression of glioma to its more malignant form, glioblastoma. Hence, one or more of the genes transactivated by p53 is likely to function as an angiogenesis inhibitors. We isolated a novel p53-inducible gene that encodes a 1584-amino-acid product containing five thrombospondin type 1 (TSP-type 1) repeats and is specifically expressed in the brain. A recombinant protein corresponding to the TSP-type 1 repeats of this gene product inhibited in vivo neovascularization induced by bFGF in the rat cornea. The expression of this gene, designated BAI1 (brain-specific angiogenesis inhibitor 1) was absent or significantly reduced in eight of nine glioblastoma cell lines, suggesting BAI1 plays a significant role in angiogenesis inhibition, as a mediator of p53.

Amino Acid Sequence↗
PubMed1997

Effect of collagen cross-linking in collagen corneal shields on ocular drug delivery.

It is well known that some ocular diseases can be treated more effectively with a collagen shield containing drug. The influence of collagen cross-linking on drug delivery is not known. We determined if collagen cross-linking affects ofloxacin bioavailability at three different collagen shield dissolution times. In this study, the collagen shields were not impregnated in drug but an eye drop was simply instilled after application of collagen shield. A non-cross-linked collagen shield, with a dissolution time of 12 h, disappeared more rapidly from the rabbits' eyes due to proteolysis after application in vivo. On the other hand, the cross-linked collagen shields, with dissolution times of 24 and 72 h, served as an ofloxacin depot and enhanced topical ofloxacin penetration into the cornea and the aqueous humor. As the dissolution times for the cross-linked collagen shield are longer than those of the non-cross-linked type, they serve as drug reservoirs. Therefore, cross-linked collagen shields might be useful ocular drug delivery devices because they can allow drug concentrations to achieve higher levels in the cornea and aqueous humor.

Absorption↗
PubMed1997

All-trans-retinoic acid-dependent inhibition of E-cadherin-based cell adhesion with concomitant dephosphorylation of beta-catenin in metastatic human renal carcinoma cells.

We previously described an in vitro invasion assay model, using a monolayer of vascular endothelial cells grown on collagen gel, that mimics the metastatic abilities of the highly metastatic human renal carcinoma cell lines, MM-1,3 and 8 and their poorly metastatic counterparts, SN12C and Cl-8. MM-1, 3 and 8 cells were observed to penetrate the monolayer of vascular endothelial cells and grew in a spreading or scattering manner with loose cell-cell contact on collagen gel or on vascular endothelial cells. SN12C and Cl-8 cells failed to penetrate and grew in a clustering manner with tight cell-cell contact. Treatment with all-trans-retinoic acid (ATRA) at non-toxic concentrations induced clustering or growth of MM-1, 3 and 8 cells on collagen gel or on vascular endothelial cells with tight cell-cell contact, and inhibited penetration. The clustering induced by ATRA was virtually blocked in the presence of anti-E cadherin antibody. E-Cadherin and beta-catenin were each localized mainly at the cell-cell adherent junctions of colonizing cell populations that had been treated with ATRA. While the cellular levels of E-cadherin and beta-catenin did not change significantly following ATRA treatment, the tyrosine residue of beta-catenin was rapidly dephosphorylated. The concomitant administration of Na vanadate, an inhibitor of tyrosine dephosphorylase, inhibited both the ATRA-induced clustering and the dephosphorylation of beta-catenin tyrosine. ATRA-induced clustering of MM-3 cells may be linked to the state of tyrosine phosphorylation of beta-catenin.

Adult↗
PubMed1997

Altered expression of gamma-glutamylcysteine synthetase, metallothionein and topoisomerase I or II during acquisition of drug resistance to cisplatin in human ovarian cancer cells.

This study was designed to elucidate the mechanisms of cisplatin (CDDP) resistance using two human ovarian cancer cell lines, KF and TYK, and two CDDP-resistant lines, KFr and TYK/R, derived from the former lines. KFr and TYK/R showed about 3-fold higher resistance to the cytotoxic effects of CDDP than their parental lines. They also showed a significant increase in sensitivity to not only etoposide, but also (+)-(4S)-4, 11-diethyl-4-hydroxy-9-[(4-piperidino -piperidino)carbonyloxy]-1H -pyrano[3',4':6,7]inodolizino[1,2-b]quinoline-3,14(4H, 12H)-dione hydrochloride trihydrate (CPT-11). Cellular CDDP accumulation levels in KFr and TYK/R were decreased from those of the parental cells. By contrast, the cellular glutathione (GSH) content in KFr cells was 1.7-fold higher than that in KF, whereas TYK/R cells had a 40% lower content than TYK cells. Cellular mRNA levels of drug-resistance-related genes, such as DNA topoisomerase (topo) I and topo II, glutathione S-transferase-pi (GST-pi), gamma-glutamylcysteine synthetase (gamma-GCS), and metallothionein (hMT) genes, were compared between drug-sensitive KF or TYK and KFr or TYK/R. KFr cells had 8.5- and 24.7-fold higher mRNA levels of gamma-GCS and topo II genes than KF cells while KFr had only a slight increase in GST-pi mRNA level as compared with KF. By contrast, TYK/R cells had 2.9- and 1.7-fold higher hMT and topo I mRNA levels than TYK cells. Acquisition of CDDP resistance in human ovarian cancer cells thus appeared to be related mainly to expression of gamma-GCS, topo II and hMT genes, and partly to that of topo I and GST-pi genes, in addition to a decrease in CDDP accumulation.

Antineoplastic Agents↗
PubMed1997

Involvement of interleukin-8, vascular endothelial growth factor, and basic fibroblast growth factor in tumor necrosis factor alpha-dependent angiogenesis.

Tumor necrosis factor alpha (TNF-alpha) is a macrophage/monocyte-derived polypeptide which modulates the expression of various genes in vascular endothelial cells and induces angiogenesis. However, the underlying mechanism by which TNF-alpha mediates angiogenesis is not completely understood. In this study, we assessed whether TNF-alpha-induced angiogenesis is mediated through TNF-alpha itself or indirectly through other TNF-alpha-induced angiogenesis-promoting factors. Cellular mRNA levels of interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors were increased after the treatment of human microvascular endothelial cells with TNF-alpha (100 U/ml). TNF-alpha-dependent tubular morphogenesis in vascular endothelial cells was inhibited by the administration of anti-IL-8, anti-VEGF, and anti-bFGF antibodies, and coadministration of all three antibodies almost completely abrogated tubular formation. Moreover, treatment with Sp1, NF-kappaB, and c-Jun antisense oligonucleotides inhibited TNF-alpha-dependent tubular morphogenesis by microvascular endothelial cells. Administration of a NF-kappaB antisense oligonucleotide almost completely inhibited TNF-alpha-dependent IL-8 production and partially abrogated TNF-alpha-dependent VEGF production, and an Sp1 antisense sequence partially inhibited TNF-alpha-dependent production of VEGF. A c-Jun antisense oligonucleotide significantly inhibited TNF-alpha-dependent bFGF production but did not affect the production of IL-8 and VEGF. Administration of an anti-IL-8 or anti-VEGF antibody also blocked TNF-alpha-induced neovascularization in the rabbit cornea in vivo. Thus, angiogenesis by TNF-alpha appears to be modulated through various angiogenic factors, both in vitro and in vivo, and this pathway is controlled through paracrine and/or autocrine mechanisms.

Animals↗
PubMed1997

Upregulation of low density lipoprotein receptor by gemfibrozil, a hypolipidemic agent, in human hepatoma cells through stabilization of mRNA transcripts.

Gemfibrozil reduces the plasmal levels of cholesterol and triglyceride in patients with hyperlipidemia by a mechanism that is not well understood. The present study evaluated the effect of gemfibrozil on the LDL receptor in human hepatoma cells compared with that of pravastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase. Exposure to gemfibrozil, 40 mumol/L, for 3 days increased the binding of 125I-LDL to the surface of three lines of human hepatoma cell, HepG2, HuH7, and HLE by 1.5- to 2.0-fold. Similar findings were observed with pravastatin. Scatchard analysis with 125I-LDL indicated an increased number of LDL receptors on the cell surface of HepG2 cells when treated with gemfibrozil and pravastatin. However, the gemfibrozil-treated cells exhibited no increase in the binding of 125I-epidermal growth factor (EGF). Gemfibrozil increased the levels of LDL receptor mRNA and protein in HepG2 cells. The increase in LDL receptor activity induced by pravastatin was abolished by concomitant administration of mevalonic acid, 770 mumol/L. This effect was not seen with gemfibrozil, suggesting the mechanism differs for the two lipid-lowering drugs. To determine whether this increase in mRNA was due to transcriptional activation, we prepared HepG2 cells transfected with an LDL receptor promoter-reporter construct that contained a sterol regulatory element. The expression of LDL receptor regulated by the sterol regulatory element was increased by pravastatin, but not by gemfibrozil. We evaluated the stability of the mRNA in the presence of actinomycin D to explain the increase in the LDL receptor mRNA. Gemfibrozil prolonged the half-life of the mRNA for LDL receptor but not that for the EGF receptor. Stabilization of the LDL receptor mRNA is suggested to be the novel mode of action of gemfibrozil.

Carcinoma, Hepatocellular↗
PubMed1997

[Development of anti tumor agents targeting angiogenesis].

Aberrant angiogenesis is closely involved in invasion/metastasis as well as enlargement of tumor. One recent highlight is to develop anti angiogenic drugs by targeting tumor angiogenesis. Here we describe how tumor angiogenesis is regulated and also recent topics related to angiogenic drug in clinical trials.

Antineoplastic Agents↗
PubMed1997

Enhanced expression of gamma-glutamylcysteine synthetase and glutathione S-transferase genes in cisplatin-resistant bladder cancer cells with multidrug resistance phenotype.

PURPOSE: To elucidate the mechanisms of cisplatin resistance in human bladder cancer. MATERIALS AND METHODS: After continuous exposure of KK47 cells to cisplatin, two resistant sublines, KK47/DDP10 and KK47/DDP20 were established. The glutathione content, glutathione S-transferase activity, and intracellular platinum concentration were measured while the expression of various drug resistance-related genes was examined. RESULTS: KK47/DDP10 and KK47/DDP20 were respectively 9.3- and 18.7-fold more resistant to cisplatin than KK47, and also showed multidrug resistance. Decreased intracellular drug accumulation, increased glutathione content, elevated glutathione S-transferase activity, and an overexpression of gamma-glutamylcysteine synthetase and glutathione S-transferase pi genes were observed in the resistant sublines. CONCLUSIONS: Multiple mechanisms, including decreased drug accumulation, increased intracellular glutathione and glutathione S-transferase pi, may contribute to the acquisition of cisplatin resistance in human bladder cancer.

Antineoplastic Agents↗