Biomedical subjects

M Kuwano

Publications and source records attributed to M Kuwano.

At least 271 records · Page 15Linked to original sources

PubMed1985

Isolation of retinoic acid-resistant clones from human breast cancer cell line MCF-7 with altered activity of cellular retinoic acid-binding protein.

After ethyl methane sulfonate mutagenesis of the mammary carcinoma cell line, MCF-7, we have isolated three clones, U-2, U-3, and U-9, resistant to retinoic acid. These three clones showed more than a 1000-fold higher level of resistance to retinoic acid than the parental MCF-7 cells when assayed by colony formation in monolayer culture system or by growth curves. The three resistant clones showed a 200-fold higher resistance to 13-cis-retinoic acid, about 10-fold higher resistance to retinol, and about 2-fold higher resistance to retinyl acetate, respectively, than MCF-7. Binding of [3H]retinoic acid or [3H]-retinol to a cellular fraction in situ showed apparent decrease of the specific binding of retinoic acid in U-2, but there was no such specific fraction bound to retinol in U-2 and MCF-7. Sucrose gradient analysis with cytoplasmic fraction showed little, if any, cellular retinoic acid-binding protein in U-2, but a significant amount of the cellular retinoic acid-binding protein could be found in MCF-7. By contrast, there was no activity of cellular retinol-binding protein in both MCF-7 and U-2. The sensitivity or resistance of mammalian cells in culture to retinoic acid is discussed in relation with cellular binding activity for vitamin A.

Breast Neoplasms↗

PubMed1985

Potentiation by vitamin A of the action of anticancer agents against murine tumors.

Combinations of retinol palmitate (RP) and six different anticancer agents were examined to determine their effects on the life-span of mice bearing ascites sarcoma 180 or P388 leukemia. With ascites sarcoma 180, administration of a fixed dose of RP (3.3 mg/kg) considerably enhanced the antitumor effects of 5-fluorouracil (5-FU) (5 mg/kg, or 20 mg/kg), methotrexate (MTX) (0.5 mg/kg, or 1 mg/kg) and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) (12.5 mg/kg), when given by intraperitoneal injection. However RP failed to potentiate the antitumor effects of adriamycin (ADM) and 6-mercaptopurine (6-MP) against sarcoma 180. With P388 leukemia, RP (167 mg/kg, or 333 mg/kg) enhanced the antitumor effects of 6-MP (25 mg/kg, or 50 mg/kg), MTX (1 mg/kg, or 2 mg/kg), ADM (0.2 mg/kg), ACNU (5 mg/kg) and cis-dichlorodiammine-platinum (CDDP) (1 mg/kg) to a considerable extent, but it did not potentiate the antitumor effect of 5-FU. The combination of RP with ACNU or CDDP was particularly effective against P388 leukemia.

Animals↗

PubMed1985

Potentiation by squalene of antitumor effect of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-nitros ourea in a murine tumor system.

The effect of squalene (SQ) on the antitumor activity of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitros our ea (ACNU) was studied in a murine tumor system. SQ at 4.2 g/kg exhibited a significant potentiating effect on the activity of 10 mg/kg of ACNU against lymphocytic leukemia P388 and resulted in some long-term survivors without toxicity to the host. Simultaneous administration of SQ and ACNU was most effective.

Animals↗

PubMed1984

Chinese hamster cell mutants with defective endocytosis of low-density lipoprotein contain altered fatty acid composition in the membrane.

Chinese hamster V79 cell mutants resistant to compactin (ML236B), a specific inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, are defective in endocytosis of low-density lipoprotein (1). Two resistant clones, MF-2 and MF-3, differ in lipid composition from the parental V79 strain. In both the total cells and membrane fraction, the ratio of palmitoleic acid (16:1)/palmitic acid (16:0) is 0.4-0.5 in MF-2 and 1.7-1.8 in MF-3 while that in V79 is 0.2-0.3. By contrast, a hybrid clone between V79 and MF-3 shows a ratio of palmitoleic acid to palmitic acid very similar to that of V79. The synthesis of palmitoleic acid from acetate in the resistant clone is higher than in V79.

Acetates↗

PubMed1984

Chinese hamster ovary cell variants resistant to monensin, an ionophoric antibiotic. I. Isolation and altered endocytosis of ricin.

Chinese hamster ovary (CHO) cell variants resistant to a carboxylic ionophore, monensin, have been isolated. Two monensin-resistant variants (MonR-31 and MonR-32) showed a three- to fourfold higher resistance to monensin than did CHO. These MonR clones also showed fourfold higher resistance to another carboxylic ionophore, nigericin, and twofold higher resistance to valinomycin. They were also slightly more resistant to other unrelated drugs such as adriamycin, colchicine, bleomycin, and chloroquine, and in particular, they showed about threefold higher resistance to ricin, a toxin of Ricinus communis. MonR clones were found to retain a normal level of [125I]ricin binding, but internalization of [125I]ricin into the MonR clones was one-half or less than with CHO. Present data suggest that drug-resistant clones selected in culture may provide a way to isolate cells with altered response to various bioactive molecules.

Animals↗

PubMed1984

Chinese hamster ovary cell variants resistant to monensin, an ionophoric antibiotic. II. Growth requirement for insulin and altered insulin-receptor activity.

From the Chinese hamster ovary (CHO) cell, genetic variants (MonR-31 and MonR-32) relatively resistant to monensin, an ionophoric antibiotic, have been isolated. Growth of both MonR-31 and MonR-32 clones required higher doses of serum than CHO. Addition of insulin to media containing a low dose of serum restored full colony formation, but growth of MonR-31 or MonR-32 cells required more insulin than CHO cells. Specific binding of [125I]insulin was observed in these cell lines. The two MonR clones bound about one-half or less the [125I]insulin bound by CHO cells. Scatchard analysis for [125I]insulin binding at 4 degrees C and 37 degrees C showed altered number of binding sites, but not insulin affinity: The number of binding sites in the MonR cell was about a half or less that of the parental CHO cell. Down-regulation of insulin receptor was assayed when both CHO and MonR cells were incubated with 1 microgram/ml insulin. A 50-60% decrease in levels of insulin surface binding capacities was observed in CHO after exposure to insulin, whereas there was no decrease in MonR cell. The cellular uptake of 2-[3H]deoxyglucose into CHO cells was significantly enhanced in the presence of insulin, but only slight, if any, increase was observed in MonR cells.

Animals↗

PubMed1984

Inhibition of stomal recurrence in laryngectomy with preoperative far therapy. A statistical evaluation.

FAR therapy is effective for cancers of the head and neck, in particular laryngeal cancer. This combined chemoradiotherapy consists of 5-FU, vitamin A and radiation. We found 10% stomal recurrences in reviewing 112 patients who had been treated with total laryngectomy. Stomal recurrences after total laryngectomy occur frequently in patients undergoing an emergency tracheotomy. We studied 33 such patients divided into 2 groups, on the basis of whether laryngectomy had been carried out after the emergency tracheotomy plus preoperative FAR therapy, or whether laryngectomy had been carried out without preoperative FAR therapy. The incidence of stomal recurrence was less among those given preoperative FAR therapy and was statistically significant. Such being the case, preoperative FAR therapy seems to e prophylactically effective against stomal recurrence after emergency tracheotomy.

Combined Modality Therapy↗

PubMed1984

Potentiation of anticancer agents by new synthetic isoprenoids. II. Inhibition of the growth of transplantable murine tumors.

The antitumor effects of combinations of synthetic isoprenoids-decaprenylamine.HCl, N-(p-methylbenzyl)decaprenylamine.HCl [N-(PMB)-decaprenylamine.HCl], and decaprenoic acid-with anticancer agents were studied in male ICR mice with ascites sarcoma 180 (S180) and in male BALB/c mice with fibrosarcoma Meth A. Decaprenylamine.HCl, N-(PMB)-decaprenylamine.HCl, and decaprenoic acid were tested in combination with bleomycin A2 (BLM) on S180. Decaprenoic acid was also examined in combination with BLM or 5-fluorouracil (FUra) for effects on fibrosarcoma Meth A. The dosages of synthetic isoprenoids used in the combination therapy were much below the median lethal dose. In the low-dosage schedule, decaprenylamine.HCl, N-(PMB)-decaprenylamine.HCl or decaprenoic acid considerably enhanced the antitumor effect of BLM on S180; e.g., the T/C value (mean survival time of treated mice/mean survival time of controls) for decaprenylamineHCl plus BLM, N-(PMB)-decaprenylamine.HCl plus BLM, or decaprenoic acid plus BLM was 294, 357, and 279% respectively, and the combinations increased life-span 2.4-fold, 2.3-fold, or 1.8-fold, respectively, as compared to the effects of BLM alone. The combination of BLM or FUra with decaprenoic acid, when administered by iv injection to mice with fibrosarcoma Meth A (solid tumor system), did not produce synergism. However, a preventive effect of decaprenoic acid monotherapy was observed: Decaprenoic acid at 3 mg/kg resulted in 38.9% suppression of tumor growth 21 days after inoculation.

Animals↗

PubMed1984

Phosphorylation of membrane proteins in monensin-resistant mutant of Chinese hamster ovary cell with altered insulin-receptor activity.

A Chinese hamster ovary (CHO) cell mutant resistant to the Na+/K+ ionophoric antibiotic, monensin, is partly defective in insulin-receptor activity. Growth of the monensin-resistant mutant required higher dose of insulin in defined medium than the parental CHO cell. Membrane proteins of CHO and a monensin-resistant clone, MonR-31, were compared for their capacity to be phosphorylated by endogenous phosphorylation enzyme in vitro in the absence or presence of insulin. Several membrane proteins of CHO were more highly phosphorylated as compared with MonR-31 in either the absence or presence of insulin.

Animals↗

PubMed1984

Imidazole-resistant phenotype and virus transformation in cultured rat cells.

Compared to an untransformed rat cell line, 3Y1, adenovirus 12-transformed cell lines of 3Y1 were highly sensitive to the cytotoxic action of an imidazole antibiotic, clotrimazole. In contrast, SV40-transformed rat cell lines derived from the 3Y1 cell line showed no appreciable difference in the response to clotrimazole when compared to 3Y1 cells. Clotrimazole-resistant clones, WCT-1 and WCT-2, which were spontaneously isolated from the adenovirus 12-transformed cell line W5, showed 5- to 10-fold higher resistance than did W5; the dose-response curves of clotrimazole-resistant clones were similar to those of the untransformed 3Y1 cells. The growth of 3Y1 cells was blocked in the presence of 1% serum, whereas those of W5, WCT-1, and WCT-2 cells were only slightly affected by the same dose of serum in the medium. The membrane fractions of 3Y1, W5, and WCT-1 cells were found to contain similar cholesterol:phospholipid ratios. The phospholipid composition in the membrane fraction of line WCT-1 was similar to that of line W5 but not to that of line 3Y1. By contrast, the fatty acid composition was specifically altered in clotrimazole-resistant clones; cellular contents and some species of fatty acid such as 16:1, 18:2, and 20:4 in WCT-1 and WCT-2 cells were similar to those of 3Y1 but not to those of W5 cells. Differential sensitivities of various cell lines to clotrimazole are discussed in relation to the lipid composition.

Animals↗

PubMed1983

Increased surface binding sites of insulin in ML236B (compactin)-resistant mutants of Chinese hamster cell line.

Mutants resistant to ML236B (compactin) were isolated from the Chinese hamster lung V79 cell line (1). Three ML236B-resistant mutants, MF-1, MF-2 and MF-3, were enhanced in insulin-specific binding activity about 2 to 3 times over the parental V79 cell lines. Compared to V79, endocytosis of insulin was also increased 2 to 3-fold in ML236B-resistant mutants than V79. Scatchard analysis showed that 5,000 insulin binding sites per cell in V79 and 16,000 in a NL236B-resistant clone, MF-2. Insulin receptors in mutant and parental strains are down-regulated to a similar extent in the parental V79 treated with an excess insulin. This is the first somatic cell mutant with increased surface binding sites for insulin.

Animals↗

PubMed1983

Verapamil enhances the efficiency of DNA-mediated gene transfer in mammalian cells.

Treatment of Ltk- cells with the calcium antagonists, verapamil and diltiazem, but not nifedipine, causes a 3-fold enhancement of the frequency of transfer of the cloned gene for herpes simplex virus thymidine kinase (HSV-tk). The frequency of phenotypic expression of the HSV-tk DNA was 20 to 34 times higher than that of genotypic transformation. Phenotypic expression was also 2.3 to 2.6 times increased when 20 micrograms/ml of verapamil was present during calcium phosphate-mediated DNA transfection.

Animals↗

PubMed1983

Isolation and characterization of vitamin A-sensitive Chinese hamster lung cell lines.

Retinyl acetate (RA)-sensitive variants (RAs-2 and RAs-3) of V79 cell line were isolated after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. The variants were stable and showed a 3- to 4-fold increase in sensitivity to RA compared to parental V79 cells. The RAs-2 clone was also sensitive to retinol and retinol palmitate. The RA-sensitivity behaves as a recessive trait in all hybrids of RAs-2 and V79. A number of physiological parameters were indistinguishable in V79 and RAs-2 cells, including the extent of uptake of [3H]retinol, the release of K+ from the cells induced by RA, and the levels of retinol and retinoic acid binding proteins. However, one possible correlation with the RA-sensitive phenotype was observed: Gomori acid-phosphatase staining of RA-treated RAs-2 and V79 cells indicated that lysosomal membrane of RAs-2 cells was more labile than those of the parental V79 cells.

Animals↗

PubMed1983

Secondary mutation resistant to 7-ketocholesterol rescues a sterol metabolic defect in amphotericin B-resistant Chinese hamster cell line.

Amphotericin B-resistant mutants isolated from Chinese hamster V79 cells (1) are defective in cholesterol synthesis and more sensitive to an oxygenated sterol analog, 7-ketocholesterol, than their parental cell line. We isolated 7-ketocholesterol-resistant mutants from an amphotericin B-resistant mutant, AMBR-1. The 7-ketocholesterol-resistant mutants had regained increased level of free cholesterol, and they showed somewhat similar dose-response curves to amphotericin B as that of V79. Sterol synthesis from acetate, but not from mevalonate, in 7-ketocholesterol-resistant clones was threefold higher than that of AMBR-1. 7-Ketocholesterol-resistant clone, unlike AMBR-1, could form colonies in the presence of lipoprotein-depleted serum. The results are discussed in terms of probable change in the sterol biosynthetic pathway by the different lesions.

Amphotericin B↗

PubMed1983

Ultrastructural changes during the enhancement of cellular 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase in a Chinese hamster cell mutant resistant to compactin (ML 236B).

Chinese hamster V79 cell mutants resistant to compactin (ML236B) were isolated. A resistant clone, MF-2, grown in the presence of 2 micrograms/ml of ML236B for 1 week showed a 30-fold increase in 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-Co A) reductase activity compared to MF-2 grown in the absence of ML236B, and cells grown for 4 weeks showed a 53-fold increase. Apparent ultrastructural changes in thin sections of the MF-2 cells were observed after growth in ML236B: dilated cisternae in the rough endoplasmic reticulum had or did not have flocculated contents; there was significant distension of perinuclear space; and vesicular inclusion bodies were present in nuclei.

Animals↗

PubMed1983

Pimaricin potentiation of bleomycin activity against murine tumors.

Antitumor activity of bleomycin against Ehrlich ascites carcinoma in mice was examined in the presence and absence of a polyene antibiotic, pimaricin. A single intraperitoneal (ip) injection of bleomycin and pimaricin in combination into tumor-bearing mice on day 1 produced a synergistic life-prolongation effect as compared with that of each agent alone. Accumulation of abdominal ascites was almost completely blocked by bleomycin in combination with the tetraene antibiotic. Frequent ip injection of small doses of bleomycin and pimaricin on day 1 produced a much greater increase in life span than the single ip injection. To obtain effective synergism under these treatment schedules, it appeared that the dose of bleomycin should be reciprocally proportional to the dose of pimaricin.

Animals↗

PubMed1983

Potentiation of mitomycin C, 6-mercaptopurine, bleomycin, cis-diamminedichloroplatinum and 5-fluorouracil by mycotrienins and mycotrienols.

Mycotrienins I and II and mycotrienols I and II are ansamycin antibiotics containing a triene structure, isolated from Streptomyces rishiriensis. An amphotericin B-resistant clone (AMBR-1) derived from cultured Chinese hamster V79 cells was cross-resistant to mycotrienins I and II, but not to mycotrienol I or II. These four ansamycin antibiotics were found to potentiate significantly the action of some anti-cancer agents including 5-fluorouracil, cis-diamminedichloroplatinum, bleomycin, mitomycin C and 6-mercaptopurine against cultured V79 cells. The action of adriamycin was not potentiated. These four ansamycin antibiotics showed a synergism spectrum similar to that of smaller polyene antibiotics.

Animals↗

PubMed1983

[Retinoids and cancer].

In this article, we survey recent advances in basic as well as clinical studies on retinoids including structure-function correlation of retinoids, effects of retinoids on cell growth, anticancer activities, immunological potentiation, initiation and promotion of cancer, differentiation, and chemoprevention.

Animals↗