Biomedical subjects

T Tsuruo

Publications and source records attributed to T Tsuruo.

At least 325 records · Page 18Linked to original sources

PubMed1992

Therapeutic efficacy of combination of antitumor agent with AHC-52 against multidrug-resistant cells in the intravenously inoculated P388 leukemia model.

To predict the clinical effect on leukemic disease of a combination regimen developed to circumvent multidrug resistance (MDR), we tested various antitumor agents in the presence and absence of AHC-52, a sensitizing agent for multidrug-resistant cells, in the i.v.-i.v. model of murine leukemia. In this model system, sensitive and resistant P388 murine leukemia cells are inoculated i.v. into mice, and each antitumor agent is injected via the i.v. route. Vincristine (VCR) had no effect on the survival of mice bearing VCR-resistant P388, a relatively poorly resistant subline, when given either as a single agent or in combination with AHC-52. In contrast, adriamycin (ADR) alone had no effect on these mice, but its combination with AHC-52 resulted in significant survival, the maximal value achieved being 196% (treated mice/control animals, T/C). Etoposide (VP-16) strongly enhanced survival, even when used alone, and this effect was markedly potentiated by AHC-52. Combination of any antitumor drug with AHC-52 was ineffective in mice bearing ADR-resistant P388, a highly resistant subline. On the other hand, AHC-52 strongly augmented the therapeutic efficacy of these antitumor agents in mice bearing the sensitive parent P388 leukemia, producing some curative effects. On the basis of these results, the feasibility of this type of combination therapy is discussed.

Animals↗

PubMed1992

Preferential expression and activity of multidrug resistance gene 1 product (P-glycoprotein), a functionally active efflux pump, in human CD8+ T cells: a role in cytotoxic effector function.

The multidrug resistance gene 1 (mdr 1) product, the P-glycoprotein (Pgp), is a 170-kD transmembrane transport protein, whose overexpression is associated with multidrug resistance in cancer cells and in chloroquine-resistant Plasmodium falciparum infection. In this study we show that normal freshly isolated human lymphocytes express low levels of mdr 1 mRNA and membrane Pgp. Although Pgp is expressed in both CD4+ and CD8+ T cells, it is preferentially expressed in CD8+ T cells. Activation of T lymphocytes with phytohemagglutinin leads to an amplification of both mdr 1 mRNA and membrane Pgp in T cells. P-glycoprotein in T cells is a functionally active efflux pump as demonstrated by decreased retention of rhodamine-123 and its increased accumulation by cyclosporin A, an inhibitor of Pgp function. In addition, MRK-16 antibody increased accumulation of Rh123 in CD8+ T cells. Furthermore, MRK16 anti-P-glycoprotein monoclonal antibody, in a concentration-dependent manner, inhibited T lymphocyte-mediated cytotoxicity. These data suggest a physiologic role of P-glycoprotein in cytotoxic T-lymphocyte effector function.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Expression of a human multidrug resistance gene in human ovarian carcinoma cell lines.

To investigate the possible role of the multidrug resistance phenotype to chemoresistance in human ovarian carcinoma, we have analyzed human multidrug resistance gene (mdr 1) expression in 8 human ovarian adenocarcinoma cell lines. An increase in P-glycoprotein level specific to multidrug-resistant tumor cells was not apparently associated with the increase in resistance to vincristine (VCR) or doxorubicin (Adriamycin). Mdr 1 transcripts (4.5 kilobases) were observed in the RNA preparation obtained from only one cell line (SHIN-3) that showed the highest resistance to both drugs in vitro and in vivo. No cell lines showed mdr 1 DNA amplification. These results suggest that the insensitivity of human ovarian carcinoma to chemotherapy could be partly explained by the expression of mdr 1.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

P-glycoprotein as the drug efflux pump in primary cultured bovine brain capillary endothelial cells.

The expression of a functional P-glycoprotein (P-gp) which pumps drugs out of brain capillary endothelial cells (BCEC) into blood was studied by evaluating the steady-state uptake and efflux of vincristine (VCR) by primary cultured bovine BCEC. The steady-state uptake of VCR was increased in the presence of metabolic inhibitors, and an anti-P-gp monoclonal antibody, MRK16, as well as verapamil and steroid hormones which are known to reverse multidrug resistance in tumor cells. Furthermore, efflux of VCR from BCEC was inhibited by verapamil. By immunohistochemistry, P-gp was localized at the luminal side of the capillary endothelial cells in both gray matter of bovine brain and primary cultured BCEC. These data suggest that P-gp functions as a drug efflux pump at the luminal side of BCEC and regulates the transfer of certain lipophilic drugs from the blood into the brain.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Establishment and characterization of doxorubicin-resistant human bladder cancer cell line, KK47/ADM.

A human bladder cancer cell line resistant to doxorubicin, KK47/ADM has been established in vitro by exposing KK47 parent cells to progressively higher concentrations of the drug over a period of 16 months. The KK47/ADM was 271 times more resistant to doxorubicin than the KK47 parent. The KK47/ADM exhibited cross-resistance to doxorubicin derivatives (pirarubicin, epirubicin), vinca alkaloids (vinblastine, vincristine) and etoposide, but not to cisplatin, carboplatin, mitomycin C, peplomycin and methotrexate. Unlike the KK47 parent, about 70% of the KK47/ADM cells showed a positive reaction with monoclonal antibody against P-glycoprotein, MRK16. Uptake and efflux studies with [14C]doxorubicin indicated that the resistance exhibited by the KK47/ADM line was mainly due to a lower accumulation of the drug caused by an increased active efflux, and these were reversed in the presence of verapamil. Although verapamil enhanced doxorubicin sensitivity of KK47/ADM, a complete overcoming of the resistance could not be obtained. These two lines with different chemosensitivity are thus considered to be a useful model for developing new chemotherapeutic strategies against multidrug resistant bladder cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Augmentation by bispecific F(ab')2 reactive with P-glycoprotein and CD3 of cytotoxicity of human effector cells on P-glycoprotein positive human renal cancer cells.

A bispecific F(ba')2 was constructed that was composed of two Fab fragments, one derived from anti-CD3 monoclonal antibody (mAb) (OKT3) and the other from anti P-glycoprotein mAb (MRK 16). This bispecific F(ab')2 enhanced the binding and cytotoxicity of human peripheral blood mononuclear cells (PBMCs) on P-glycoprotein-positive human kidney cancer cells (ADMHK/E). It had no effect on the cytotoxicity of PBMCs on P-glycoprotein-negative HK/E cells [long-term cultured HK/E (LCHK/E)]. Control F(ab')2 composed of OKT3 or MRK16 alone did not influence the cytotoxicity of PBMCs on ADMHK/E cells. These findings suggest that the MRK16-OKT3 bispecific F(ab')2 may be therapeutically beneficial in treatment of human multidrug-resistant cancers.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Effector cell analysis of human multidrug-resistant cell killing by mouse-human chimeric antibody against P-glycoprotein.

A mouse-human chimeric monoclonal antibody (mAb), MH162, against P-glycoprotein was previously found to be more effective than an all-mouse mAb (MRK16) in lysis of multidrug-resistant (MDR) tumor cells by blood mononuclear cells. The present study was performed to identify the effector cells responsible for the chimeric mAb-dependent cell-mediated cytotoxicity (ADCC) against MDR cells. The ADCC reaction was assessed by a 6-h 51Cr release assay. Highly purified lymphocytes (greater than 99%), monocytes (greater than 99%) and neutrophils (greater than 96%) were obtained from peripheral blood of the same healthy donors. A comparison of these three effector cell populations showed no difference between MH162 and its all-murine counterpart MRK16 in MDR cell lysis by monocytes or neutrophils. But MH162 was more effective than MRK16 in lymphocyte-mediated lysis of the MDR cells. The lymphocytes responsible for this ADCC had CD16+ Fc receptors. Pretreatment of monocytes with colony-stimulating factors (IL-3, GM-CSF and M-CSF) caused significant increase in their MH162-mediated lysis of MDR cells. Another anti-P-glycoprotein chimeric mAb (MH171) was also more effective than its murine counterpart MRK17 in lymphocyte-mediated lysis of MDR cells. These findings suggest that mouse-human chimeric mAbs may be useful therapeutically for in vivo destruction of MDR cancer cells by the ADCC reaction.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Mouse-human chimeric antibody MH171 against the multidrug transporter P-glycoprotein.

We have developed a mouse-human chimeric antibody MH171, in which the antigen-recognizing variable regions of the mouse monoclonal antibody MRK17 are joined with the constant regions of human IgG1 antibodies. The MRK17 recognizes specifically the multidrug transporter P-glycoprotein and inhibits the growth of human multidrug resistant (MDR) tumor cells in vitro and in the xenograft nude mouse model system. The established chimeric MH171 antibody forms an apparently intact IgG composed of heavy and light chains covalently assembled via disulfide bonds in sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis and is specific to MDR cell lines with a similar affinity to the original mouse MRK17. MH171 also displays strong antibody-dependent cell-mediated cytotoxicity to the target cells in vitro, when human mononuclear cells are used as effector cells. The chimeric antibody against P-glycoprotein, MH171, should be a useful agent in the treatment of human drug-resistant tumors.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Expression of 85-kDa protein of adriamycin-resistant tumor cells during hematopoietic differentiation of THP-1 and HEL cells.

An 85-kDa protein was identified in adriamycin-resistant tumor cells recognized by monoclonal antibody MRK-20. Recently, the monoclonal antibody MRK-20 was found to be reactive to human peripheral mononuclear cells. In order to investigate the molecular function of the 85-kDa protein, we carried out flow cytometric analysis of the expression of the 85-kDa protein during monocytic differentiation of the hematopoietic cells. Human myelomonocytic leukemia THP-1 cells were induced to differentiate into macrophage-like cells by treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA). A maximum of 55% of the cells expressed the 85-kDa protein along with the CD-14 antigen, which is a surface marker of monocytes and macrophages. The kinetic analysis revealed that the 85-kDa protein appeared prior to the expression of the CD-14 antigen. The 85-kDa protein was also coexpressed with CD-14 in THP-1 cells that were induced to differentiate by recombinant tumor necrosis factor-alpha, which is one of the physiological inducers of monocytic differentiation. In human erythroleukemia, HEL cells, the 85-kDa protein was constitutively coexpressed with CD-14. The expression of both the 85-kDa protein and CD-14 was drastically reduced during the megakaryocytic differentiation of the HEL cells with TPA. These results suggest that the 85-kDa protein could be expressed on monocytic cells as well as CD-14 and that the expression of the 85-kDa protein might be regulated at an earlier stage of monocytic differentiation of hematopoietic cells than the expression of CD-14.

Antigens, CD↗

PubMed1992

Reactivity of P-glycoprotein monoclonal antibodies in childhood cancers.

P-Glycoprotein (P-gp), the product of the mdr-1 gene, is implicated in the development of chemoresistance in a variety of, mostly adult, cancers. Its role in paediatric tumours, most of which are non-epithelial in origin, has yet to be fully elucidated. A study was undertaken to investigate reactivity of two P-gp monoclonal antibodies (MAbs), JBS-1 and MRK16, recognising cytoplasmic and surface epitopes, respectively, of the P-gp molecule, in a variety of newly diagnosed and relapsed childhood cancers. P-gp was not expressed in any of 36 tumours examined (neuroblastoma 13, nephroblastoma 12, rhabdomyosarcoma 6, lymphoma 3, teratoma 1, Ewings 1), 14 of whom had chemoresistant disease. Reactivity to both MAbs was also investigated in patients with acute leukaemia. Out of 10 diagnostic acute lymphoblastic leukaemia (ALL) samples, a positive reaction with JSB-1 was observed in 1 patient who failed to remit on standard induction therapy and in 3 of 6 patients in ALL relapse, only 1 of whom showed low grade positivity with MRK16. Both MAbs reacted positively in 1 patient with acute non-lymphocytic leukaemia (ANLL) at diagnosis who achieved remission with teniposide and cytosine arabinoside, but relapsed 7 months later and was again positive with both Mabs. JSB-1 also showed varying degrees of positivity in 4 out of 4 other patients in ANLL relapse. It would therefore appear that P-gp is unlikely to mediate chemoresistance in most solid tumours of childhood, but may well play a major role in the development of chemoresistance in acute leukaemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Synthesis and antitumor activity of fused quinoline derivatives. III. Novel N-glycosylamino-indolo[3,2-b]quinolines.

Novel indolo[3,2-b]quinolines (1b-k), having a nitro, amino, acetamido, methanesulfonamido, or glycosylamino group at the 2, 7, or 8-position, were prepared and their antitumor activities against P388 leukemia in mice were examined. The 7-galactopyranosylamino derivative (1g) showed the most potent activity (optimal dose = 25 mg/kg, T/C greater than 333%, cure rate 5/6).

Animals↗

PubMed1992

Mechanism of action of an antifungal antibiotic, RI-331, (S) 2-amino-4-oxo-5-hydroxypentanoic acid; kinetics of inactivation of homoserine dehydrogenase from Saccharomyces cerevisiae.

An antifungal antibiotic (S) 2-amino-4-oxo-5-hydroxypentanoic acid, inhibited the biosynthesis of the aspartate family of amino acids (methionine, isoleucine and threonine) followed by the inhibition of protein biosynthesis in Saccharomyces cerevisiae. This inhibition was effected by impeding the biosynthesis of their common intermediate precursor, homoserine. The inhibition of biosynthesis of homoserine by the antibiotic was attributable to inactivation of homoserine dehydrogenase [EC 1.1.1.3], which is involved in the conversion of aspartate semialdehyde to homoserine in the metabolic pathway leading to threonine, methionine and isoleucine. Since such enzymic activity is not present in animal cells, the selective antifungal activity of the antibiotic is thus explained.

Aminolevulinic Acid↗

PubMed1992

Role of protein kinase C in the modulation of multidrug resistance: expression of the atypical gamma isoform of protein kinase C does not confer increased resistance to doxorubicin.

Cross-resistance to anticancer drugs, termed multidrug resistance (MDR), is functionally associated with the expression of a plasma membrane, energy-dependent, drug efflux pump termed P-glycoprotein (PGP), the product of the mdr1 gene. We have shown previously that MCF-7 breast carcinoma cells transfected with the human mdr1 gene (BC-19 cells) exhibit greater MDR when stably transfected with protein kinase C alpha (PKC alpha). We now demonstrate that transfection of BC-19 cells with the gamma isoform of PKC (BC-19/PKC gamma cells), which is not normally present in BC-19 cells, does not confer increased resistance to doxorubicin, despite a 19-fold increase in PKC activity. All of the increased PKC activity is accounted for by PKC gamma and it is rapidly down-regulated by phorbol dibutyrate, within 15 min of treatment. Endogenous PKC alpha and PKC epsilon activities are not affected by phorbol dibutyrate. The cytotoxicity of doxorubicin was similar in BC-19/neo or BC-19/PKC gamma cells after either 2-hr or continuous drug exposure, and co-treatment with phorbol dibutyrate increased resistance to doxorubicin 4-fold in both cell lines. Phosphorylation of PGP was similar in both cell lines and drug accumulation was not affected by overexpression of PKC gamma. These results demonstrate that transfection of PGP-expressing cells with an atypical isoform of PKC does not confer increased MDR, and they suggest that the regulation of PGP is phenotype specific with respect to the isoform of PKC.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1991

Insulin-like growth factor I rapidly induces tyrosine phosphorylation of a Mr 150,000 and a Mr 160,000 protein in highly metastatic mouse colon carcinoma 26 NL-17 cells.

Insulin-like growth factor I (IGF-I) stimulates the proliferation of highly metastatic NL-17 cells to a greater extent than poorly metastatic NL-44 cells, both of which are derived from mouse colon carcinoma 26. The NL-17 cells have been compared with NL-44 cells for the signal transduction pathway of IGF-I. IGF-I receptors of both cell types were identified by affinity labeling, and there was no significant difference between the two cell types in the amount or the autophosphorylation activity of the IGF-I receptors. However, when IGF-I-dependent tyrosine phosphorylation of cellular components was examined, remarkable tyrosine phosphorylation of proteins with molecular weights of 150,000 (pp150) and 160,000 (pp160) was found in NL-17 cells. In contrast, this phosphorylation stayed at significantly lower levels in NL-44 cells than in NL-17 cells. The phosphorylation of pp150 and pp160 was induced within 10 s after the addition of IGF-I and reached its maximal level by 30 s. After the removal of IGF-I, the phosphorylation of pp150 and pp160 was reduced to the basal level within 30 min. This phosphorylation was not induced by platelet-derived or epidermal growth factor. The pp150 and pp160 were not absorbed by wheat germ agglutinin-agarose. They were found in the soluble fraction of cytoplasm but not in the membrane or the cytoskeleton. The pp150 and pp160 might be endogenous substrates of IGF-I receptor kinase. These results suggest that tyrosine phosphorylation of pp150 and pp160 mediates the higher proliferative response of NL-17 cells to IGF-I.

Animals↗

PubMed1991

Reversal of drug resistance in a human colon cancer xenograft expressing MDR1 complementary DNA by in vivo administration of MRK-16 monoclonal antibody.

One strategy to overcome multidrug resistance in neoplasia is to inhibit the gp170 glycoprotein (relative molecular mass, 170,000) that functions as a plasma membrane, energy-dependent, drug-efflux pump. The human colon cancer cell line HT-29, which grows as an ascitic tumor in athymic NCr-nu/nu nude mice, was made multidrug resistant by infection with an MDR1 (also known as PGY1) retrovirus. Referred to as HT-29mdr1, it was used to study reversal of drug resistance in vivo by the anti-P-glycoprotein monoclonal antibody MRK-16. Flow cytometry and radioimmunoassay demonstrated a marked increase in MRK-16 reactivity on HT-29mdr1 cells as compared with its reactivity on the parental, uninfected cell line (HT-29par). The 50% inhibitory concentrations (IC50) of vincristine on HT-29par and HT-29mdr1 cells were 2.5 and 15 ng/mL, respectively. The MRK-16 monoclonal antibody did not affect the vincristine sensitivity of the HT-29par cells. Pretreatment of HT-29mdr1 cells with 10 micrograms/mL MRK-16 in tissue culture partially restored the vincristine sensitivity (IC50 = 7 ng/mL). This modulation of vincristine sensitivity by MRK-16 was then tested in vivo. The median survival times of mice given intraperitoneal transplants of 5 x 10(6) HT-29par or HT-29mdr1 were 37 and 39 days, respectively. Treatment of mice with 1 mg/kg vincristine weekly for 3 weeks, beginning 10 days after tumor injection, resulted in a significant increase in the median survival time of the HT-29par tumor-bearing mice (68 days, P less than .0001), but it had no effect on the HT-29mdr1 tumor-bearing mice. However, treatment of mice bearing the HT-29mdr1 tumor with MRK-16 before vincristine therapy reversed the resistance to the drug (median survival time = 64 days, P less than .0001). The MRK-16 monoclonal antibody alone had no effect on the median survival time of mice given an injection of either HT-29par or HT-29mdr1 cells. These results suggest that strategies employing monoclonal antibody against gp170 may be clinically useful to reverse multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1991

Reversal of adriamycin resistance by recombinant alpha-interferon in multidrug-resistant human colon carcinoma LoVo-doxorubicin cells.

Reversal of the drug resistance phenotype by the use of agents which induce cell differentiation offers an experimental approach to the study of chemoresistance. In numerous in vitro models, alpha-interferon (alpha-IFN) has been shown to induce phenotypical changes and to modulate the growth of cancer cells. The aim of the present study was to define the effect of alpha-IFN on the Adriamycin sensitivity of the human colon adenocarcinoma cell line, LoVo, and its Adriamycin-resistant variant, LoVo/DX. Pretreatment of LoVo/DX cells with 500 units/ml of alpha-IFN increased sensitivity to low doses of Adriamycin. Similar treatment conditions did not change the sensitivity of the parental cell line. Following treatment of the LoVo/DX cells with alpha-IFN plus 100 ng/ml Adriamycin for 1 h, 30% of the cells survived compared to 100% of untreated cells. This effect was not related to changes in cell cycle kinetics induced by alpha-IFN treatment and did not result from variations in the expression of P-glycoprotein at the cell surface, as assessed by flow cytometric analysis using monoclonal antibody MRK16. Adriamycin accumulation was increased by alpha-IFN as assessed by spectrofluorometric analysis. Thus, the data suggest that in LoVo/DX cells, alpha-IFN increased Adriamycin cytotoxicity through modulation of the multidrug resistance phenotype.

Adenocarcinoma↗

PubMed1991

Multidrug resistance after retroviral transfer of the human MDR1 gene correlates with P-glycoprotein density in the plasma membrane and is not affected by cytotoxic selection.

Multidrug resistance (MDR) in mammalian cells is associated with the expression of the MDR1 gene encoding P-glycoprotein (P-gp), an and active efflux pump for various lipophilic compounds. MDR transfectants can be isolated after MDR1 gene transfer and selection with cytotoxic drugs; low levels of drug resistance have also been observed in unselected NIH 3T3 mouse cells after retrovirus-mediated transfer of mouse mdr1 cDNA. MDR cell lines possess multiple phenotypic changes, suggesting that P-gp function could be complemented by some additional mechanisms associated with cytotoxic selection. To determine whether cytotoxic selection contributes to the MDR phenotype of MDR1-expressing cells, NIH 3T3 cells infected with a recombinant retrovirus carrying the human MDR1 gene were selected by two different procedures: (i) noncytotoxic selection for increased P-gp expression on the cell surface by multiple rounds of immunofluorescence labeling and flow sorting or (ii) one or more steps of selection with a cytotoxic drug. The levels of MDR in both types of infectants showed an excellent correlation with the P-gp density in the plasma membrane, expressed as immunoreactivity with a P-gp-specific antibody normalized by reactivity with an antibody against an unrelated antigen. Cytotoxic selection conferred no additional increase in resistance relative to P-gp density. These results indicate that P-gp density in the plasma membrane may be sufficient to determine the level of MDR.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1991

Inhibition by erythroid differentiation factor (activin A) of P-glycoprotein expression in multidrug-resistant human K562 erythroleukemia cells.

The K562/VCR cell line, exhibiting acquired multidrug resistance (MDR) with increased expression of a cell surface glycoprotein (P-glycoprotein), was isolated from human erythroleukemia K562 cells. Various compounds that induced erythroid differentiation of K562 cells were tested for their effects on growth and differentiation of these K562/VCR cells. Sodium butyrate, hemin, 1-beta-D-arabinofuranosylcytosine, and erythroid differentiation factor (EDF) induced erythroid differentiation of K562/VCR cells as well as K562 cells. The MDR of K562/VCR cells was partly overcome by treatment with EDF but not with the other inducers. Expression of P-glycoprotein by K562/VCR cells was measured by radioimmunoassay using MRK16 monoclonal antibody. Results showed that EDF caused down-regulation of P-glycoprotein in K562/VCR cells, whereas the other inducers did not cause its down-regulation. Thus, in addition to inducing erythroid differentiation, EDF enhanced the sensitivity of K562/VCR cells to multidrugs and suppressed expression of P-glycoprotein. These results suggest that differentiation inducers may be useful in chemotherapy of leukemic MDR cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗