Biomedical subjects

T Tsuruo

Publications and source records attributed to T Tsuruo.

539 records · Page 30Linked to original sources

PubMedDate not supplied

Growth stimulating activity of lung extract on lung-colonizing colon 26 clones and its partial characterization.

The effects of lung tissue extract on the cell growth of eight colon 26 tumor clones, four highly and four poorly lung-colonizing clones, were examined in vitro. Addition of lung extract to serum-free medium stimulated the growth of all four of the highly lung-colonizing clones and one of the poorly lung-colonizing clones, but it had minimal effect on the other three poorly lung-colonizing clones. These results indicate that the lung extract contains a growth stimulating activity; it selectively stimulated some of the colon 26 clones including highly lung-colonizing ones. The growth stimulating activity was not dialyzable, was partially destroyed by heating at 56 degrees C or 80 degrees C for 30 min and completely destroyed by trypsin. These results suggest that the activity resides in a protein. Gel filtration chromatography of lung extract on Sephacryl S-200 revealed that the active component was eluted in a molecular weight range of 90,000-120,000.

Animals↗

PubMedDate not supplied

Development of lymphosarcoma lines with high metastatic ability to lymph nodes and visceral organs in BALB/c mice.

A metastatic tumor population was isolated in BALB/c mice during routine s.c. passage of the colon 26 adenocarcinoma. The tumor metastasized to lymph nodes, liver, spleen, ovary and kidney. A primary culture established from the s.c. growing tumor was composed of both adherent and nonadherent cells. These two cell types were successfully separated from the primary culture and designated CMS (suspension cells) and CMA (adherent cells). The CMS and CMA cell lines are morphologically distinct in culture; however both formed similar histopathologic tumors when inoculated s.c. Furthermore, both tumor lines showed identical metastatic patterns in BALB/c mice with involvement of lymph node, liver, spleen, ovary and kidney. CMS and CMA expressed T-antigen as revealed by FITC-labeled-anti-Thy 1.2 antibody. Chromosome analysis and morphologic studies by light and electron microscopy indicated that the present metastatic lines have no relationship with the colon 26 adenocarcinoma and seem to be non-thymic T-cell lymphosarcomas which developed spontaneously in BALB/c mice.

Animals↗

PubMedDate not supplied

p21Waf1/Cip1 expression is a prognostic marker in curatively resected esophageal squamous cell carcinoma, but not p27Kip1, p53, or Rb.

BACKGROUND: p21Waf1/Cip1 (p21), p27Kip1 (p27), p53, and Rb play critical roles in cell cycle regulation and may influence the clinical behavior of tumors. We examined whether their expression is useful to predict survival of patients with esophageal squamous cell carcinoma (ESC). METHODS: Expression of p21, p27, p53, and Rb was studied by the immunohistochemical method in specimens from 62 patients with curatively resected ESC tumors and scored by a computerized image analysis system. RESULTS: The median expression scores of p21, p27, p53, and Rb (14, 12, 27, and 50, respectively) were used as cut-off points to define low and high expression groups for each protein. The 5-year survival rate for the high p21 expression group was 68%; that for the low expression group was 31% (P = .0062). p27, p53, and Rb were not correlated with overall survival. When patients were categorized into four groups based on p21 expression level and lymph node involvement (pN), the survival curves were significantly different (P = .0017). Thus, patients without lymph node involvement but with low p21 expression had survival similar to that of patients with lymph node involvement and high p21 expression. Multivariate analysis showed that age (P = .0102), lymph node involvement (P = .0076), and p21 (P = .0276) were independent prognostic factors. CONCLUSIONS: Expression of p21 is an independent prognostic factor in curatively resected ESC. Definition of new subgroups of patients based on p21 expression may help to enhance the stratification of stage.

Adult↗

PubMedDate not supplied

Anti-tumor effect of N-beta-alanyl-5-S-glutathionyldihydroxyphenylalanine (5-S-GAD), a novel anti-bacterial substance from an insect.

PURPOSE: We examined the anti-tumor effect of 5-S-GAD, a novel potent inhibitor of protein tyrosine kinases, isolated from the flesh fly in order to investigate the potential use of this compound as an anti-tumor agent. METHODS: In vitro growth inhibition was evaluated using the alamarBlue assay kit. In vivo anti-tumor activity was evaluated by i.p. treatment of 5-S-GAD against xenografted melanoma (LOX-IMV1) and breast carcinoma (MDA-MB-435S) in nude mice. RESULTS: Of 38 human cancer cell lines examined, this compound showed significant cytotoxicity toward two estrogen-negative breast carcinomas (MDA-MB-231 and MDA-MB-435S) and one malignant melanoma (LOX-IMV1) in vitro, indicating that it exhibits selective cytotoxicity to certain tumor cell lines. In accordance with its in vitro anti-tumor effect, 5-S-GAD was shown to significantly repress the growth of sensitive tumor cells in nude mice. CONCLUSION: These results indicate that 5-S-GAD is potentially useful to treat certain human cancer.

Animals↗

PubMedDate not supplied

Anticancer activities of orally administered menogaril against human stomach and breast cancers implanted in nude mice.

The therapeutic effects of orally administered menogaril, a semisynthetic analog of the anthracycline antibiotic nogalamycin, were studied on a panel of human stomach and breast cancer xenografts. The maximum tolerated dose (200 mg/kg) of menogaril was administered 3 times every 4 days and its growth-inhibitory effects on subcutaneously implanted tumors in nude mice were evaluated. Menogaril significantly retarded the growth of 3 out of 7 stomach cancers, SC-2, SC-9 and 4-1ST, and 3 out of 4 breast cancers, H-31, MC-2 and MX-1, with overall response rates of 43 and 75% for stomach and breast cancers, respectively. Some of these relatively responsive cancers were also treated by daily oral administration for 5 consecutive days, but the anticancer effects of the intermittent administration seemed to be better. These results suggest that menogaril may be effective against stomach and breast cancers when orally administered.

Administration, Oral↗

PubMedDate not supplied

Expression of the multidrug-resistant gene in human musculoskeletal tumors.

We measured the levels of messenger RNA of the human multidrug-resistant (MDR) gene in 15 human musculoskeletal tumors. In metastatic tumors and those which did not respond to combination chemotherapy, there was an increased expression of this gene. No evidence of expressions of the MDR gene was found in the benign tumors. The high expression of the MDR gene from musculoskeletal tumors apparently induced a multidrug resistance, and this acquired resistance may be due to outgrowth of the P-glycoprotein-expressing MDR tumor. Elucidation of expression of the MDR gene is an important step in malignant musculoskeletal tumors research.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Inhibition of ubiquitin-ATP-dependent proteolysis and ubiquitination by cisplatin.

We tested the inhibitory activity of various antitumor agents on the ubiquitin-ATP-dependent proteolytic activity in rabbit reticulocyte lysates. We found that cisplatin, 4'-(9-acridinyl-amino) methanesulfon-m-anisidide (m-AMSA) and mitomycin C inhibited the ubiquitin-ATP-dependent proteolysis. IC50 values (50% inhibition concentrations) of these antitumor agents were 90, 210 and above 290 microM, respectively. Furthermore, cisplatin was found to inhibit the conjugation of ubiquitin to endogenous proteins in fraction II at 100 and 330 microM. These results suggest that cisplatin interacts with the enzyme(s) involved in ubiquitin conjugation and thus inhibits the ubiquitin-ATP-dependent protein degradation. We assume that the agents that can affect the ubiquitin system might be useful for the treatment of tumors and that the ubiquitin system could be a new target for cancer chemotherapy.

Amsacrine↗

PubMedDate not supplied

Establishment of multidrug resistant human colorectal carcinoma HCT-15 cell lines and their properties.

A series of MDR cell lines with various levels of P-glycoprotein have been established from a human colorectal carcinoma cell line, HCT-15, by stepwise exposure to adriamycin. The relative drug resistance of these cell lines correlated directly with both MDR1 mRNA levels and P-glycoprotein expression levels. Intracellular accumulation of adriamycin decreased inversely to their resistance. Drug sensitivities of these lines were reversed using verapamil. Since these cell lines are transplantable to nude mice, they may provide a useful animal model of MDR solid tumors for therapeutic experiments.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Cross-resistance of human multidrug-resistant cells to mitomycin C.

Human multidrug-resistant cells, K562/ADM, KB-C-4, AdrRMCF-7 and CEM/VLB100 showed 21-, 7.5-, 105- and 3.4-fold cross-resistance to mitomycin C (MMC). The resistance to MMC in K562/ADM, KB-C-4, AdrRMCF-7, CEM/VLB100 cells was reversed by 6.6 microM verapamil. Accumulation of [3H]MMC in K562/ADM, AdrRMCF-7 and CEM/VLB100 cells also decreased by 37, 26 and 33%, as compared with their drug-sensitive counterparts. In KB-C-4 cells, accumulation of [3H]MMC decreased by 60%, and efflux rate of [3H]MMC was slightly increased as compared to their parental KB-3-1 cells. Verapamil at 6.6 microM increased accumulation of [3H]MMC in these multidrug-resistant sublines. K562/ADM10, K562/ADM50, K562/ADM100 and K562/ADM250 cells, which showed 17- to 230-fold resistance to Adriamycin, also showed 0.8- to 7.3-fold cross-resistance to MMC. In these cell lines, the extent of resistance to Adriamycin (ADM) that was consistent with expression levels of P-glycoprotein shown by immunoblotting was directly proportional to the extent of their resistance to MMC. Regression analysis indicated that relative resistance to Adriamycin was correlated with relative resistance to MMC (r = 0.98). These results indicate that MMC can be transported by P-glycoprotein overexpressed in multidrug-resistant cells.

Doxorubicin↗

PubMedDate not supplied

Characteristics of vincristine resistance in vincristine resistant human myelogenous leukemia K562.

A stable vincristine (VCR)-resistant variant (K562/VCR) was established from human myelogenous leukemia K562 by continuous exposure of the cells with increasing concentration of VCR up to 30 nM, followed by the maintenance of the cells in the presence of 30 nM of VCR for 6 months. In four clones with different VCR sensitivity, the extent of VCR-resistance and Adriamycin-resistance was always parallel among the clones, indicating a tight relationship between VCR- and ADM-resistance mechanisms. The clones accumulated significantly low amounts of VCR in the cells. The amounts of VCR in the clones and K562/VCR were inversely related to the extent of resistance of the cells. The rate and the extent of VCR efflux from the cells were parallel to the extent of resistance of the cells to VCR. One VCR-resistant clone, KV-11, was found to possess diminished amounts of beta-tubulin.

Biological Transport↗

PubMedDate not supplied

Difference in effects of alkyl-lysophospholipids and verapamil on vincristine transport in vincristine-sensitive and -resistant human myelogenous leukemia K562.

Several kinds of alkyl-lysophospholipids enhanced the accumulation of vincristine (VCR) in both drug-sensitive and -resistant K562 cells. The drugs also augmented the efflux of VCR from the tumor cells. It is assumed that alkyl-lysophospholipids made tumor cells permeable to both the influx and efflux of VCR. The alkyl-lysophospholipids produced nonspecific effects of almost equal intensity in both sensitive and resistant tumor cells. These effects were compared with those of verapamil, a calcium channel blocker. Verapamil, as reported previously, specifically inhibited the efflux of drugs from tumor cells, especially drug-resistant tumor cells, thereby enhancing the accumulation of antitumor agents in the cells. Thus the actions of alkyl-lysophospholipids and verapamil in tumor cells were obviously different. Furthermore, the combined effects of alkyl-lysophospholipids and verapamil were additive or synergistic, indicating that their sites of action may be different.

Cell Line↗

PubMedDate not supplied

Characterization of four doxorubicin adapted human breast cancer cell lines with respect to chemotherapeutic drug sensitivity, drug resistance associated membrane proteins and glutathione transferases.

Four human breast cancer cell lines with or without estrogen and progesterone receptors were adapted to growth in the continuous presence of doxorubicin (Dox) at 10 (Zr-75-1), 15 (HTB-122), or 50 (MDA-MB-231 and Hs578T) ng/ml. The sublines of Zr-75-1, MDA-MB-231 and Hs578T showed 5-10-fold Dox resistance and also cross-resistance to vincristine (VCR) and etoposide (VP16). The sublines of Zr-75-1, MDA-MB-231 and Hs578T showed 5-10-fold Dox resistance and also cross-resistance to vincristine (VCR) and etoposide (VP16). The sublines maintained or slightly increased their cis-platinum (CDDP) sensitivity. The sublines of HTB-122 showed resistance only to VP16 combined with a paradoxical increased sensitivity to VCR. The phenotypic alteration in the sublines with respect to Dox sensitivity was maintained for at least two months in the absence of Dox. The glutathione depletor buthionine sulfoximine (BSO) and the calcium channel blocker verapamil (Ver) increased the Dox sensitivity slightly only in the MDA-MB-231 and Hs578T sublines, respectively. Ver also tended to protect some of the sublines from CDDP. The sublines of Zr-75-1 and Hs578T showed increased expression of the 170-kDa permeability glycoprotein (P-gp), whereas expression of a 85-kDa membrane protein determined by the MRK20 antibody was increased in the sublines of Zr-75-1, and HTB-122. Class pi glutathione transferase (GST) levels varied greatly between the cell lines but increased during Dox selection only in the subline of Zr-75-1. Class mu GST was detectable in the MDA-MB-231, Hs578T and HTB-122 cell lines, whereas class alpha GST was detectable in these sublines but undetectable in their parental cell lines. The Zr-75-1 subline showed a 5-fold increase in the class alpha concentration. Except for a correlation between increased P-gp expression and resistance to Dox, VCR and VP16, no obvious correlations between receptor status, increased P-gp expression, membrane proteins, GST levels and acquired drug resistance were found. Thus, except for a possible role for P-gp in multidrug-resistance, these findings indicate a pronounced mechanistic heterogeneity responsible for cytotoxic drug sensitivity also in cells with a common histologic origin and exposed to the same drug.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Antitumor activity of idarubicin, a derivative of daunorubicin, against drug sensitive and resistant P388 leukemia.

Idarubicin (IDA) possessed high antitumor activity against mouse P388 leukemia. When P388 leukemia bearing mice were administered an optimal dose of IDA intravenously, 200-250% of T/C and some cured mice were obtained. IDA showed a partial but significant effect against daunorubicin (DNR)-resistant P388 leukemia, whereas DNR, its parent drug, did not. Although IDA failed to show activity against doxorubicin (DX)- and aclarubicin (ACR)-resistant P388 leukemia in this study, IDA might have chemotherapeutic effects in patients in relapse and refractory to other anthracyclines. This assumption is supported by the results on the growth inhibition study in vitro. Among the metabolites, only idarubicinol showed cytotoxicity against P388 leukemia and idarubicinol showed 38% of the activity of IDA, indicating that the active components in animals could be IDA and idarubicinol. The combination of IDA and Ara-C induced some additive effect in P388 leukemia bearing mice as compared to the results with single drug usage.

Aclarubicin↗

PubMedDate not supplied

Establishment of a daunorubicin-resistant cell line which shows multi-drug resistance by multifactorial mechanisms.

We established a daunorubicin (DNR)-resistant cell line derived from human leukemia cell line K562, (K562/D1-9), which also shows multidrug resistance (MDR). K562 cells were cultured with serially increasing concentrations up to 1.0 microM of DNR and then cloned by the limiting dilution method. K562/D1-9 cells were found to be 28 times more resistant to DNR than their its parent cells. Intracellular accumulation of DNR in K562/D1-9 was less than in the wild type, and P-glycoprotein (PGP) was overexpressed. Both DNR resistance and its intracellular accumulation were partially reversed by addition of verapamil to K562/D1-9 cells, but not to K562 cells. Topoisomerase II (Topo II) activity was decreased in K562/D1-9 cells. In contrast to other drugs, such as doxorubicin and vincristine, verapamil could not reverse drug resistance to VP-16 in the K562/D1-9 cell line, suggesting the importance of Topo II as the target of MDR. Protein kinase C (PKC) level was higher in K562/D1-9 than in K562. These findings suggested that the mechanism of MDR in this cell line might be multifactorial, including PGP, topo II and PKC. The K562/D1-9 cell line may be a good model for studying drug resistance in leukemia chemotherapy.

Antibiotics, Antineoplastic↗

PubMedDate not supplied

Coexpression of a multidrug resistance gene (MDR1) and herpes simplex virus thymidine kinase gene in a bicistronic retroviral vector Ha-MDR-IRES-TK allows selective killing of MDR1-transduced human tumors transplanted in nude mice.

Ha-MDR-IRES-TK is a bicistronic vector that coexpresses the MDR1 gene and the herpes simplex virus thymidine kinase (HSV-TK) gene. In the present study we examined the effect of ganciclovir on MDR1-positive tumors that have been transduced with Ha-MDR-IRES-TK. To establish a human tumor xenograft model of MDR1-transduced recurrent tumors, human KB-3-1 carcinoma cells were transduced with HaMDR or Ha-MDR-IRES-TK, and one each of representative clones, termed KB/MDR and KB/MDR-TK, respectively, were isolated. KB/MDR and KB/MDR-TK showed similar levels of multidrug resistance in vitro. Vinblastine strongly inhibited the growth of the parental KB-3-1 tumors in nude mice but showed little or no effect against KB/MDR-TK tumors. Ganciclovir inhibited the in vivo growth of KB/MDR-TK tumors almost completely under conditions that did not affect the growth of KB-3-1 tumors. Coadministration of vinblastine and ganciclovir inhibited the in vivo growth of KB/MDR-TK premixed with KB-3-1 at any ratio. Long-term, high-level expression of human P-glycoprotein was observed in peripheral blood cells of mice transplanted with Ha-MDR-IRES-TK-transduced bone marrow cells. Ganciclovir eliminated the P-glycoprotein-positive normal blood cells. However, no systemic toxicity was observed. These results clearly demonstrate that it is possible to use ganciclovir to treat MDR1-positive tumors that have been unintentionally transduced with Ha-MDR-IRES-TK. This safety-modified vector should be useful for introducing the MDR1 gene into bone marrow cells to protect normal cells from the toxic effects of cancer chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

MDR-related properties of K 562 cells grown in two different culture media.

Using a synthetic substitute, Ultroser HY, for fetal bovine serum to supplement a classical RPMI 1640 culture medium produced changes in the properties of sensitive and of multidrug-resistant K 562 cells. Though no morphological changes were found, a statistically significant decrease in doubling-time was noted. Plasma membranes were more rigid, as reflected by an increase in the order parameter values. Adriamycin cytotoxicity was decreased, as shown by an increase in IC 50 values. The THP-adriamycin uptake, monitored by fluorimetry, was diminished even when the revertant agent verapamil was added. Moreover, the apparent number of Pgp 170 molecules per cell was lower for resistant cells grown with Ultroser HY. Thus Pgp 170 was not involved in the MDR increase induced by Ultroser HY. In conclusion, it must be kept in mind that environmental factors such as media chemical composition influence the MDR phenomenon and that environmental factors may also influence the MDR phenomenon in clinical situations.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Dihydropyrimidine dehydrogenase but not thymidylate synthase expression is associated with resistance to 5-fluorouracil in colorectal cancer.

BACKGROUND/AIMS: In planning adjuvant treatment of colorectal cancer, it is of critical importance to optimize the treatment by identifying subsets of patients that will respond or not to chemotherapy. Thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) are key enzymes involved in the biochemical functions of the antimetabolite 5-fluorouracil (5-FU). In searching for the factors determining the 5-FU sensitivity of colorectal cancer, TS and DPD were analyzed in relation to the inhibitory effect of 5-FU on cell proliferation in a series of human colorectal cancer cell lines. METHODOLOGY: TS and DPD protein expressions were quantified in 5 human colorectal cancer cell lines, using TS binding assay and Western blotting, respectively. Cellular growth inhibition was assessed by MTT assay after 48 hours of continuous exposure to 5-FU or cisplatin (CDDP). RESULTS: TS protein expression was detected in all but one of the cell lines studied and varied within a 17-fold range, while DPD protein expression was detectable in only one cell line (CaR1). CaR1, which expressed the highest level of DPD and no detectable TS, showed remarkable resistance to 5-FU. The other colorectal cancer cell lines with undetectable DPD expression were sensitive to 5-FU. There was no correlation between TS expression and 5-FU sensitivity. All of the cell lines studied showed similar sensitivity to CDDP. CONCLUSIONS: These data suggest that DPD, but not TS, expression predicts 5-FU sensitivity in colorectal cancer cell lines.

Antimetabolites, Antineoplastic↗