251
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Moretti JL, Caglar M, Duran-Cordobes M, Morere JF. Can nuclear medicine predict response to chemotherapy? EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1995; 22:97-100. [PMID: 7758509 DOI: 10.1007/bf00838937] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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252
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van der Heyden S, Gheuens E, DeBruijn E, Van Oosterom A, Maes R. P-glycoprotein: clinical significance and methods of analysis. Crit Rev Clin Lab Sci 1995; 32:221-64. [PMID: 7495497 DOI: 10.3109/10408369509084685] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Multidrug resistance (MDR) is responsible for a decrease in sensitivity of tumor cells tumor cells to unrelated, naturally occurring anticancer drugs. This resistance is correlated with expression and activity of a membrane protein, P-gp 170, functioning as a drug-extruding pump. It has been well described in in vitro situations; however, the clinical detection and implications are not yet clear. Multiple detection assays have been developed based on the discovery of the MDR gene family and the corresponding protein. Southern, Northern, or Western blot analysis, S1 nuclease protection or PCR-based assays, immunohistochemical detection or functionality tests by flow cytometry have been used extensively. However, by use of these techniques on clinical material, both normal and malignant, contradictory results have emerged. The sensitivity and specificity of a certain technique are always limited by unavoidable parameters, for example, skill of the technician. Moreover, the complexity of the development of resistance against anticancer agents (external determinants), such as the diversity of tumor tissues, the simultaneous presence of other resistance mechanisms, and the low expression level, make MDR detection equivocal and can lead to contradictory results. Previous treatment influencing the MDR profile and inappropriate timing of the test make a possible correlation between MDR expression and chemotherapeutic resistance difficult to establish and can lead to discordant results. In this review, the need for proper criteria is stressed. No single detection technique provides the ideal test to detect MDR. Tandem testing could give more certainty, although small sample size limit this application. Formulation of a standard assay with better definition of a positivity is essential before clinical trials are started.
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Affiliation(s)
- S van der Heyden
- Laboratory for Cancer Research and Clinical Oncology, University of Antwerp, Universiteitsplein 1 (T-3), Wilrijk, Belgium
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253
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Hubbard AL, Lauder J, Hawkins RA, Anderson TJ. Disregulation of urokinase plasminogen activator gene in breast cancer. Eur J Cancer 1995; 31A:103-7. [PMID: 7695959 DOI: 10.1016/0959-8049(94)00430-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Disregulation of urokinase plasminogen activator (uPA) was assessed in 134 breast cancer specimens. Overexpression of uPA was determined by immunohistochemistry using the specific monoclonal antibody, #394. Gene amplification was assessed by differential polymerase chain reaction, using primers designed to amplify a 111 bp segment of the uPA gene. Overexpression of uPA was detected in 33% of breast cancers, including 4 of 21 in situ carcinomas, 7 of 14 lobular and 2 of 10 tubular carcinomas. Overexpression of uPA did not correlate with the presence or absence of oestrogen receptors. uPA gene amplification was not detected in any cancer. We conclude that uPA gene amplification is not a major mechanism instigating uPA overexpression in breast cancer, and that overexpression is likely to be controlled by other mechanisms.
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Affiliation(s)
- A L Hubbard
- Department of Pathology, University of Edinburgh, Medical School, U.K
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254
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Kirschner LS. Amplification of the murine mdr2 gene and a reconsideration of the structure of the murine mdr gene locus. DNA Cell Biol 1995; 14:47-59. [PMID: 7832992 DOI: 10.1089/dna.1995.14.47] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A common feature of cells selected in vitro for the multidrug resistance (MDR) phenotype is the amplification and concomitant overexpression of the mdr genes. In murine macrophage-like J774.2-derived MDR cell lines, there is a good correlation between levels of amplification and expression for the mdr1b gene, but not for the other two gene family members, mdr1a and mdr2. To understand this phenomenon better, a study of the amplification and expression of the mdr2 gene was undertaken. Southern blotting of genomic DNAs from a series of six MDR cell lines revealed that five of these lines had 5'-end amplification of mdr2, whereas only three contained 3'-end amplification. The analysis also suggested the involvement of a recombination hot-spot in this phenomenon. Despite the observation that the ratio between the number of copies of the 5' and 3' ends of the gene differs among cell lines, the ratio of 5' to 3' end transcription of mdr2 was approximately 1 in all cell lines. An analysis of promoter methylation in MDR cell lines demonstrated that this mechanism may play a role in regulating the transcription of mdr2, but not of mdr1b. Long-range mapping of the mdr locus in parental and amplified cell lines suggested that the three mdr genes are oriented in the same direction, and also revealed the presence of a number of rearrangement events. Models for the murine mdr gene locus in wild-type cells and in a cell line containing a rearrangement are presented.
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Affiliation(s)
- L S Kirschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461
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255
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Sardini A, Mintenig GM, Valverde MA, Sepúlveda FV, Gill DR, Hyde SC, Higgins CF, McNaughton PA. Drug efflux mediated by the human multidrug resistance P-glycoprotein is inhibited by cell swelling. J Cell Sci 1994; 107 ( Pt 12):3281-90. [PMID: 7706385 DOI: 10.1242/jcs.107.12.3281] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
P-glycoprotein (P-gp), the product of the human multidrug resistance (MDR1) gene, confers multidrug resistance on cells by acting as an ATP-dependent drug transporter. A method using confocal microscopy was developed to measure the transport activity of P-gp from the rate of movement of doxorubicin, a fluorescent substrate of P-gp, across the membrane of a single cell. Recent work has shown that expression of P-gp enhances the activation of chloride channels in response to cell swelling, suggesting that membrane stretch might switch P-gp from a drug-transporting mode to a mode in which it activates chloride channels. In agreement with this idea, we find that cell swelling inhibits drug efflux in cells expressing P-gp but is without effect on the slower background efflux in cells not expressing P-gp and in cells transiently transfected with a mutated MDR1 in which the ATP hydrolysis sites had been inactivated. The identification of a novel means for inhibiting P-gp-mediated drug transport may have implications for the reversal of multidrug resistance during chemotherapy.
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Affiliation(s)
- A Sardini
- Department of Physiology, King's College London, UK
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256
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Scanlon KJ, Ishida H, Kashani-Sabet M. Ribozyme-mediated reversal of the multidrug-resistant phenotype. Proc Natl Acad Sci U S A 1994; 91:11123-7. [PMID: 7972021 PMCID: PMC45179 DOI: 10.1073/pnas.91.23.11123] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
This study examined the effects of suppressing c-fos oncogene expression on multidrug resistance (MDR). A2780S human ovarian carcinoma cells with resistance to actinomycin D were isolated and the resultant A2780AD cells exhibited the MDR phenotype. A hammerhead ribozyme designed to cleave fos RNA cloned into the pMAMneo plasmid was transfected into A2780AD cells. Induction of the ribozyme resulted in decreased expression of c-fos, as well as that of the MDR gene (mdr-1), c-jun, and mutant p53. The transformants displayed altered morphology and restored sensitivity to chemotherapeutic agents comprising the MDR phenotype. An anti-mdr ribozyme separately expressed in A2780AD cells efficiently degraded mdr-1 mRNA. However, reversal of the MDR phenotype by the anti-mdr ribozyme occurred one-fourth as rapidly as that induced by the anti-fos ribozyme. These results reinforce the central role played by c-fos in drug resistance through its participation in signal transduction pathways.
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Affiliation(s)
- K J Scanlon
- Department of Medical Oncology, City of Hope Medical Center, Duarte, CA 91010
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257
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Vollrath V, Wielandt AM, Acuña C, Duarte I, Andrade L, Chianale J. Effect of colchicine and heat shock on multidrug resistance gene and P-glycoprotein expression in rat liver. J Hepatol 1994; 21:754-63. [PMID: 7890890 DOI: 10.1016/s0168-8278(94)80235-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The multidrug resistance genes encode plasma membrane glycoproteins named P-glycoproteins, that act as an ATP-dependent drug efflux pump and decrease the cytosolic concentration of chemotherapeutic agents. It has been hypothesized that in rat liver, this protein may have a physiological role as a biliary transporter of xenobiotics and endobiotics. Some human tumor cell lines turn on the human multidrug resistance gene in response to high temperature and after exposure to toxic chemicals. Accordingly, it has been proposed that the human multidrug resistance gene is a heat shock gene. We have assessed whether two environmental stresses, heat shock or acute exposure to cytotoxic drugs (colchicine, vincristine, vinblastine and daunomycin), induce changes in the expression of multidrug resistance genes in the rat. Total cellular RNA extracted from rat liver was hybridized to a labeled human multidrug resistance gene cDNA probe. Temperature upshift did not increase the steady-state of mdr mRNA levels in the tissues studied, suggesting that the mdr genes are not activated as part of a heat shock response. The mdr mRNA levels increased in rat liver as early as 3 h after a single injection of colchicine, reached a peak (500%; p < 0.05) after around 24 h and returned to constitutive levels after 48 h. Changes in the relative content of mdr mRNA were not detected in kidney, adrenal gland and small bowel, suggesting that the in vivo induction of the mdr gene in the liver is a tissue-specific response. The other cytotoxic drugs that were tested did not increase the steady-state of mdr mRNA levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- V Vollrath
- Department of Gastroenterology, School of Medicine, Catholic University of Chile, Santiago
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258
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Zhang JJ, Jacob TJ, Valverde MA, Hardy SP, Mintenig GM, Sepúlveda FV, Gill DR, Hyde SC, Trezise AE, Higgins CF. Tamoxifen blocks chloride channels. A possible mechanism for cataract formation. J Clin Invest 1994; 94:1690-7. [PMID: 7929848 PMCID: PMC295332 DOI: 10.1172/jci117514] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Tamoxifen is an antiestrogen frequently used in the treatment of breast cancer and is currently being assessed as a prophylactic for those at high risk of developing tumors. We have found that tamoxifen and its derivatives are high-affinity blockers of specific chloride channels. This blockade appears to be independent of the interaction of tamoxifen with the estrogen receptor and therefore reflects an alternative cellular target. One of the clinical side effects of tamoxifen is impaired vision and cataract. Chloride channels in the lens of the eye were shown to be essential for maintaining normal lens hydration and transmittance. These channels were blocked by tamoxifen and, in organ culture, tamoxifen led to lens opacity associated with cataracts at clinically relevant concentrations. These data suggest a molecular mechanism by which tamoxifen can cause cataract formation and have implications for the clinical use of tamoxifen and related antiestrogens.
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Affiliation(s)
- J J Zhang
- Department of Physiology, University of Wales, Cardiff, United Kingdom
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259
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Grünebach F, Griese EU, Schumacher K. Competitive nested polymerase chain reaction for quantification of human MDR1 gene expression. J Cancer Res Clin Oncol 1994; 120:539-44. [PMID: 7519188 DOI: 10.1007/bf01221031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Tumor cell resistance to cytotoxic drugs is considered one of the major obstacles to successful chemotherapy. Multidrug resistance (MDR) describes the simultaneous expression of cellular resistance to a wide range of structurally and functionally unrelated drugs. The development of the multidrug resistance phenotype is accompanied by multiple morphological and biochemical changes: (a) increased glutathione levels in the cytoplasm, (b) modified levels of enzymes in the nucleus, particularly topoisomerase II, (c) increased DNA repair capacity and (d) overexpression of the (human) MDR1 gene encoding a transmembrane efflux pump (P-glycoprotein, gp-170), which leads to decreased intracellular accumulation and therefore to resistance to a variety of cytotoxic drugs. In this report we describe a competitive polymerase chain reaction (PCR) assay for the absolute quantification of MDR1 mRNA. This assay uses a transcript generated in vitro as an internal standard which is later coamplified together with the MDR1 cDNA. Both cDNAs exhibit the same MDR1 primer sites but differ in the length of the amplicon. For a second round of amplification we applied nested MDR1 primers and were successful in improving the sensitivity of this competitive PCR system. This test for characterizing the MDR1 expression offers high sensitivity and specificity and is therefore of great clinical relevance. It should be useful in improving monitoring and design of chemotherapy.
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Affiliation(s)
- F Grünebach
- Department of Hematology, Oncology and Immunology, Robert-Bosch-Hospital, Stuttgart, Germany
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260
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Chromosome breakage at a major fragile site associated with P-glycoprotein gene amplification in multidrug-resistant CHO cells. Mol Cell Biol 1994. [PMID: 7913517 DOI: 10.1128/mcb.14.8.5202] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Recent studies of several drug-resistant Chinese hamster cell lines suggested that a breakage-fusion-bridge mechanism is frequently involved in the amplification of drug resistance genes. These observations underscore the importance of chromosome breakage in the initiation of DNA amplification in mammalian cells. However, the mechanism of this breakage is unknown. Here, we propose that the site of chromosome breakage consistent with the initial event of P-glycoprotein (P-gp) gene amplification via the breakage-fusion-bridge cycle in three independently established multidrug-resistant CHO cells was located at 1q31. This site is a major chromosome fragile site that can be induced by methotrexate and aphidicolin treatments. Pretreatments of CHO cells with methotrexate or aphidicolin enhanced the frequencies of resistance to vinca alkaloid and amplification of the P-gp gene. These observations suggest that chromosome fragile sites play a pivotal role in DNA amplification in mammalian cells. Our data are also consistent with the hypothesis that gene amplification can be initiated by stress-induced chromosome breakage that is independent of modes of action of cytotoxic agents. Drug-resistant variants may arise by their growth advantage due to overproduction of cellular target molecules via gene amplification.
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261
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Kuo MT, Vyas RC, Jiang LX, Hittelman WN. Chromosome breakage at a major fragile site associated with P-glycoprotein gene amplification in multidrug-resistant CHO cells. Mol Cell Biol 1994; 14:5202-11. [PMID: 7913517 PMCID: PMC359039 DOI: 10.1128/mcb.14.8.5202-5211.1994] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Recent studies of several drug-resistant Chinese hamster cell lines suggested that a breakage-fusion-bridge mechanism is frequently involved in the amplification of drug resistance genes. These observations underscore the importance of chromosome breakage in the initiation of DNA amplification in mammalian cells. However, the mechanism of this breakage is unknown. Here, we propose that the site of chromosome breakage consistent with the initial event of P-glycoprotein (P-gp) gene amplification via the breakage-fusion-bridge cycle in three independently established multidrug-resistant CHO cells was located at 1q31. This site is a major chromosome fragile site that can be induced by methotrexate and aphidicolin treatments. Pretreatments of CHO cells with methotrexate or aphidicolin enhanced the frequencies of resistance to vinca alkaloid and amplification of the P-gp gene. These observations suggest that chromosome fragile sites play a pivotal role in DNA amplification in mammalian cells. Our data are also consistent with the hypothesis that gene amplification can be initiated by stress-induced chromosome breakage that is independent of modes of action of cytotoxic agents. Drug-resistant variants may arise by their growth advantage due to overproduction of cellular target molecules via gene amplification.
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Affiliation(s)
- M T Kuo
- Department of Molecular Pathology, University of Texas M. D. Anderson Cancer Center, Houston 77030
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262
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Kohno K, Tanimura H, Sato S, Nakayama Y, Makino Y, Wada M, Fojo A, Kuwano M. Cellular control of human multidrug resistance 1 (mdr-1) gene expression in absence and presence of gene amplification in human cancer cells. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32021-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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263
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Germann UA, Schoenlein PV, Zimonjic DB, Popescu NC, Pastan I, Gottesman MM. Putative "MDR enhancer" is located on human chromosome 20 and not linked to the MDR1 gene on chromosome 7. Genes Chromosomes Cancer 1994; 10:267-74. [PMID: 7522541 DOI: 10.1002/gcc.2870100408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The physiologic expression of the human multidrug resistance MDR1 gene product P-glycoprotein is controlled in a tissue- and cell-specific manner, but the regulatory mechanisms have not been characterized in great detail. Studies by Kohno et al. [(1990) J Biol Chem 265:19690-19696] suggested that a tissue-specific enhancer element located approximately 10 kb upstream from the major MDR1 transcription start site may act to increase the levels of transcription in cultured adrenal and kidney cells. Using this putative "MDR enhancer" as a probe, we isolated a 14 kb DNA fragment from a genomic DNA library prepared from human fetal liver. The restriction map and partial nucleotide sequence of this DNA fragment were consistent with the previously described data obtained for a similar piece of genomic DNA derived from human placenta by Kohno et al. (ibid.). Pulsed-field gel electrophoresis of large genomic DNA fragments, however, showed that the DNA sequences, including the putative "MDR enhancer," were not linked to the MDR1 gene. Fluorescence in situ hybridization analysis revealed that this enhancer-like element is located on chromosome 20 at band q13.1 and is, therefore, distinct from the MDR locus on chromosome 7, band q21.1. Thus, this putative regulatory element does not modulate the tissue specificity of expression of the MDR1 gene in vivo, but may play a role in the regulation of expression of another, so far unknown gene.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- Base Sequence
- Chromosomes, Human, Pair 20
- Chromosomes, Human, Pair 7
- Drug Resistance, Multiple/genetics
- Enhancer Elements, Genetic/genetics
- Genetic Linkage
- Humans
- In Situ Hybridization, Fluorescence
- Molecular Sequence Data
- Restriction Mapping
- Tumor Cells, Cultured
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Affiliation(s)
- U A Germann
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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264
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Gekeler V, Beck J, Noller A, Wilisch A, Frese G, Neumann M, Handgretinger R, Ehninger G, Probst H, Niethammer D. Drug-induced changes in the expression of MDR-associated genes: investigations on cultured cell lines and chemotherapeutically treated leukemias. Ann Hematol 1994; 69 Suppl 1:S19-24. [PMID: 7914748 DOI: 10.1007/bf01757350] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The induced expression of multiple drug resistance (MDR)-associated genes as a direct response of tumor cells to antineoplastic drugs could be an important factor influencing the success of cancer chemotherapy. We investigated the effects of such compounds on mdr1/P-glycoprotein (P-gp) gene expression and drug sensitivities in the T-lymphoblastoid human cell line CCRF-CEM and MDR sublines. Thereby, we observed that actinomycin D or adriamycin administered at sublethal concentrations induced increases of mdr1 mRNA levels and resistance within 72 h. Furthermore, on leukemia cell samples collected before and after chemotherapy we checked by a complementary DNA polymerase chain reaction (cDNA-PCR) approach for similar alterations in the relative expression levels of the MDR-associated genes (a) mdr1/P-gp (b) mrp (MDR related protein), and (c) the topoisomerase II isoforms alpha and beta. We found a concomitant increase in mdr1 and mrp gene expression combined with a decreased expression of topoisomerase II alpha in the course of the second relapse of an acute lymphoblastic leukemia (ALL). This points to the emergence of at least three different MDR mechanisms in this type of leukemia unresponsive to chemotherapy. A chronic myeloid leukemia (CML) in blast crisis, however, showed combined increases in mdr1 (about 20-fold) and mrp (about four fold) gene expression after intense but unsuccessful chemotherapy over a 6-month period. Our results indicate the occurrence of induced resistance in vitro and in vivo and suggest a contribution of the newly identified ATP-binding cassette (ABC) transporter MRP in MDR.
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Affiliation(s)
- V Gekeler
- Abteilung FP3, Byk Gulden GmbH, Konstanz, Germany
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265
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Hill BT, Whelan RD, Hurst HC, McClean S. Identification of a distinctive P-glycoprotein-mediated resistance phenotype in human ovarian carcinoma cells after their in vitro exposure to fractionated X-irradiation. Cancer 1994; 73:2990-9. [PMID: 7911070 DOI: 10.1002/1097-0142(19940615)73:12<2990::aid-cncr2820731217>3.0.co;2-l] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Clinical drug resistance is recognized in patients previously treated with radiotherapy and after chemotherapy. In vitro exposure of mammalian tumor cells to fractionated X-irradiation also resulted in the expression of drug resistance. Analysis of the resistance phenotype of irradiated Chinese hamster ovary sublines revealed P-glycoprotein overexpression, without any concomitant increase in P-glycoprotein messenger RNA, under posttranslational regulation. This study aimed to determine whether this distinctive resistance phenotype could also be identified in irradiated human tumor cells. METHODS Irradiated sublines established from two human ovarian tumor cell lines, SK-OV-3 and JA-T, which showed resistance to vincristine and to etoposide, were studied. Protein and RNA expression were quantitated by Western and Northern blotting or RNase protection assays. P-glycoprotein turnover was measured after immunoprecipitation of metabolically labelled cells. RESULTS Significant P-glycoprotein overexpression was detected using the C219 and C494 monoclonal antibodies in the two irradiated human ovarian tumor sublines. No concomitant increase in P-glycoprotein messenger RNA was detectable in the SK-OV-3/DXR10 subline, contrasting with the increased message characteristic of vincristine-selected SKVCR sublines. In addition, turnover of P-glycoprotein was significantly reduced in these DXR10 cells when compared with that measured in a vincristine-selected subline. These irradiated sublines showed reduced levels of epidermal growth factor receptors and unchanged levels of topoisomerase II, but they overexpressed c-erbB2 marginally and heat shock protein 27 significantly. These latter elevations in protein levels, however, were associated with concomitant increases in their respective messenger RNAs, implicating regulation at the transcriptional level. CONCLUSIONS Exposure of human ovarian tumor cells to fractionated X-irradiation in vitro resulted in the expression of a distinctive multiple drug resistance phenotype unusually involving posttranslational regulation of P-glycoprotein. Monitoring tumor biopsies for P-glycoprotein-associated drug resistance in patients treated with radiotherapy should evaluate protein levels rather than, or as well as, MDR1 mRNA expression.
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Affiliation(s)
- B T Hill
- Laboratory of Cellular Chemotherapy, Imperial Cancer Research Fund, London, United Kingdom
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266
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Abstract
We reported earlier that human cervical carcinoma HeLa cells exposed to 30 fractions of 0.5 Gy gamma-rays became resistant to cisplatin, methotrexate and vincristine, but retained the same sensitivity to gamma-rays and ultraviolet light. The aim of this study was to examine whether a small number of gamma-ray fractions, with a lower daily dose, may also change the sensitivity of preirradiated cells to different cytotoxic drugs. Using the modified MTT staining procedure, we found that cells preirradiated with 5 or 10 daily fractions of only 0.17 Gy gamma-rays did not alter their sensitivity to mitomycin, cisplatin, methotrexate, 5-fluorouracil, etoposide and doxorubicin. However, 10 fractions of gamma-rays induced resistance to vincristine and vinblastine. Our immunocytochemical experiments using monoclonal antibody JSB-1 show that the plasma membrane P-glycoprotein is involved in the induced resistance to Vinca alkaloids.
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Affiliation(s)
- M Osmak
- Department of Molecular Medicine, Ruder Bosković Institute, Zagreb, Croatia
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267
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Fidler IJ, Wilmanns C, Staroselsky A, Radinsky R, Dong Z, Fan D. Modulation of tumor cell response to chemotherapy by the organ environment. Cancer Metastasis Rev 1994; 13:209-22. [PMID: 7923551 DOI: 10.1007/bf00689637] [Citation(s) in RCA: 157] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The outcome of cancer metastasis depends on the interaction of metastatic cells with various host factors. The implantation of human cancer cells into anatomically correct (orthotopic) sites in nude mice can be used to ascertain their metastatic potential. While it is clear that vascularity and local immunity can retard or facilitate tumor growth, we have found that the organ environment also influences tumor cell functions such as production of degradative enzymes. The organ microenvironment can also influence the response of metastases to chemotherapy. It is not uncommon to observe the regression of cancer metastases in one organ and their continued growth in other sites after systemic chemotherapy. We demonstrated this effect in a series of experiments using a murine fibrosarcoma, a murine colon carcinoma, and a human colon carcinoma. The tumor cells were implanted subcutaneously or into different visceral organs. Subcutaneous tumors were sensitive to doxorubicin (DXR), whereas lung or liver metastases were not. In contrast, sensitivity to 5-FU did not differ between these sites of growth. The differences in response to DXR between s.c. tumors (sensitive) and lung or liver tumors (resistant) were not due to variations in DXR potency or DXR distribution. The expression of the multidrug resistance-associated P-glycoprotein as determined by flow cytometric analysis of tumor cells harvested from lesions in different organs correlated inversely with their sensitivity to DXR: increased P-glycoprotein was associated with overexpression of mdr1 mRNA. However, the organ-specific mechanism for upregulating mdr1 and P-glycoprotein has yet to be elucidated.
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Affiliation(s)
- I J Fidler
- Department of Cell Biology, University of Texas M.D. Anderson Cancer Center, Houston 77030
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268
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Chan HS, DeBoer G, Thorner PS, Haddad G, Gallie BL, Ling V. Multidrug Resistance: Clinical Opportunities in Diagnosis and Circumvention. Hematol Oncol Clin North Am 1994. [DOI: 10.1016/s0889-8588(18)30178-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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269
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McClean S, Hill BT. Modified multiple drug resistance phenotype of Chinese hamster ovary cells selected with X-rays and vincristine versus X-rays only. Br J Cancer 1994; 69:711-6. [PMID: 7908216 PMCID: PMC1968820 DOI: 10.1038/bjc.1994.134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Exposure of Chinese hamster ovary (CHO) cells to fractionated X-irradiation [ten fractions of 9 Gray (Gy)] resulted in the expression of a multiple drug resistance phenotype which was distinct from that of drug-selected cells in two features: (i) resistance to vinca alkaloids and epipodophyllotoxins but sensitivity to anthracyclines was retained; (ii) overexpression of P-glycoprotein (Pgp) but regulated by post-translational stability rather than by any elevation in Pgp mRNA (Hill et al., 1990). It was also reported that when these cells (designated DXR-10) were subsequently exposed to another ten fractions of 9 Gy (20 x 9 Gy in total), no further increases in drug resistance or in the extent of Pgp expression were observed. To examine this apparent plateauing of the drug resistance phenotype following X-ray pretreatment, DXR-10 cells were instead treated with ten pulsed vincristine exposures. The resultant cell line, designated DXR-10/VCR-10, proved to be more resistant to vincristine, implying that the effect of further drug selection was additive to that of X-ray pretreatment. In addition, these cells showed resistance to doxorubicin and increased Pgp expression which was matched by a concomitant elevation in Pgp mRNA. These findings appear to confirm that Pgp expression is differentially regulated in tumour cells showing drug resistance after drug as opposed to X-ray selection.
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Affiliation(s)
- S McClean
- Cellular Chemotherapy Laboratory, Imperial Cancer Research Fund, London, UK
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270
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Abstract
Evidence for the phenomenon of multiple drug resistance (MDR) in the well studied pathogenic protozoa has been examined. This has been placed in the more familiar context of the MDR efflux transporters and the cloned mdr genes of mammalian cells. Homologues of the mdr gene family in protozoa and their possible role in drug efflux have been compared with their mammalian counterparts. Possible mechanisms and models for drug efflux have been considered. The unusual and extensive range of substrates transported by the ATP-binding cassette (ABC) family of transporters which includes the MDRs has been raised. The impact of kinetics, structure and bioenergetics of the MDR family members on mechanisms of transport has been accentuated to argue that MDR efflux considered in isolation appears bizarre but may be better understood in a broader context.
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Affiliation(s)
- P Upcroft
- Queensland Institute of Medical Research, Bancroft Centre, Brisbane, Australia
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271
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272
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Alkan-Onyuksel H, Ramakrishnan S, Chai HB, Pezzuto JM. A mixed micellar formulation suitable for the parenteral administration of taxol. Pharm Res 1994; 11:206-12. [PMID: 7909371 DOI: 10.1023/a:1018943021705] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Taxol is a promising antitumor agent with poor water solubility. Intravenous administration of a current taxol formulation in a non-aqueous vehicle containing Cremophor EL may cause allergic reactions and precipitation upon aqueous dilution. In this study a novel approach to formulate taxol in aqueous medium for i.v. delivery is described. The drug is solubilized in bile salt (BS)/phospholipid (PC) mixed micelles. The solubilization potential of the mixed micelles increased as the total lipid concentration and the molar ratio of PC/BS increased. Precipitation of the drug upon dilution was avoided by the spontaneous formation of drug-loaded liposomes from mixed micelles. The formulation can be stored in a freeze-dried form as mixed micelles to achieve optimum stability, and liposomes can be prepared by simple dilution just before administration. As judged by a panel of cultured cell lines, the cytotoxic activity of taxol was retained when formulated as a mixed-micellar solution. Further, for the same solubilization potential, the mixed-micellar vehicle appeared to be less toxic than the standard nonaqueous vehicle of taxol containing Cremophor EL.
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Affiliation(s)
- H Alkan-Onyuksel
- Department of Pharmaceutics and Pharmacodynamics, College of Pharmacy, University of Illinois at Chicago 60612
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273
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Activation of the mouse mdr3 gene by insertion of retroviruses in multidrug-resistant P388 tumor cells. Mol Cell Biol 1994. [PMID: 8246958 DOI: 10.1128/mcb.13.12.7380] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In multidrug-resistant (MDR) derivatives of the mouse lymphoid tumor P388, the emergence of MDR is associated with overexpression and transcriptional activation of the mdr3 gene, either in the absence of (P388/VCR-10) or concomitant with (P388/ADM-2) gene amplification. In both instances, Northern (RNA) blotting analyses have suggested the presence of altered mdr3 transcripts in these cells, possibly originating from novel transcription initiation sites. The mechanisms underlying mdr3 overexpression in these cells have been investigated. In P388/VCR-10 cells, Southern blotting analyses together with genomic DNA cloning and nucleotide sequencing have demonstrated the presence of an intact mouse mammary tumor virus (MMTV) within the boundaries of intron 1 of mdr3. cDNA cloning and nucleotide sequencing indicated that this integration event results in the synthesis and overexpression of a hybrid MMTV-mdr3 mRNA which initiates within the U3 region of the 5' long terminal repeat (LTR) of the provirus. Consequently, this mRNA lacks the normal exon 1 of mdr3 but contains (i) MMTV LTR-derived sequences at its 5' end, (ii) a novel mdr3 exon, mapping within the boundaries of intron 1 downstream of the MMTV integration site and generated by alternative splicing, and (iii) an otherwise intact 3' portion of mdr3 starting at exon 2. A similar type of analysis of P388/ADM-2 cells revealed that mdr3 overexpression in these cells is associated with the integration of an intracisternal A particle (IAP) within an L1Md repetitive element, immediately upstream of mdr3. The IAP insertion results in the overexpression of hybrid IAP-mdr3 mRNA transcripts that initiate within the 3' LTR of the IAP and which contain IAP LTR-derived sequences at the 5' end spliced 14 nucleotides upstream of the normal exon 1 of mdr3. Taken together, these results indicate that independent retroviral insertions were the initial mutagenic event responsible for mdr3 overexpression and survival during drug selection of these cell lines. Amplification of the rearranged and activated mdr3 gene copy occurred during further selection for high-level drug resistance in P388/ADM-2 cells.
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274
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Affiliation(s)
- C E Herzog
- National Cancer Institute, Bethesda, MD 20892
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275
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Gottesman MM, Mickisch GH, Pastan I. In vivo models of P-glycoprotein-mediated multidrug resistance. Cancer Treat Res 1994; 73:107-128. [PMID: 7710902 DOI: 10.1007/978-1-4615-2632-2_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/physiology
- Animals
- Animals, Genetically Modified
- Antineoplastic Agents/pharmacology
- Biological Transport, Active/drug effects
- Clone Cells/drug effects
- Cloning, Molecular
- Cyclosporine/pharmacology
- Drug Resistance, Multiple
- Humans
- Male
- Mice
- Mice, Nude
- Neoplasm Transplantation
- Neoplasms, Experimental/drug therapy
- Neoplasms, Experimental/genetics
- Quinidine/pharmacology
- Recombinant Fusion Proteins/metabolism
- Reproducibility of Results
- Research Design
- Sensitivity and Specificity
- Transplantation, Heterologous
- Tumor Cells, Cultured/drug effects
- Verapamil/pharmacology
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Affiliation(s)
- M M Gottesman
- National Cancer Institute, Laboratory of Cell Biology, Bethesda, MD 20892
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276
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/physiology
- Antineoplastic Agents/pharmacology
- Cloning, Molecular
- Colchicine/pharmacology
- DNA, Circular/genetics
- Drug Resistance, Multiple/genetics
- Gene Amplification
- Gene Expression Regulation, Neoplastic
- Humans
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- Neoplasms/genetics
- Neoplasms/metabolism
- Tumor Cells, Cultured/drug effects
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Affiliation(s)
- P V Schoenlein
- Medical College of Georgia, Department of Cell and Molecular Biology, Augusta 30912
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277
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Devine SE, Melera PW. Functional studies with a full-length P-glycoprotein cDNA encoded by the hamster pgp1 gene. Cancer Chemother Pharmacol 1994; 33:465-71. [PMID: 7907953 DOI: 10.1007/bf00686502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Hamster cells grown in culture may, like human and mouse cells, develop multidrug resistance (MDR) when exposed to certain cytotoxic chemotherapeutic agents. Several phenotypic features that are characteristic of MDR have been described; these include (1) resistance to many structurally and functionally unrelated drugs that have different cellular targets and modes of action; (2) reversal of MDR by certain agents, including verapamil and cyclosporin A; and (3) reduced intracellular drug accumulation relative to that of drug-sensitive cells. In this report we show that the introduction and overexpression of the hamster pgp1 cDNA confers to otherwise drug-sensitive cells an MDR phenotype with these features. Moreover, pgp1 transfectants showed varying degrees of resistance to anthracycline analogues, indicating that structural analogues of commonly used anticancer agents are capable of circumventing drug resistance conferred by pgp.
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Affiliation(s)
- S E Devine
- Department of Biological Chemistry, University of Maryland School of Medicine, Baltimore 21201
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278
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Skovsgaard T, Nielsen D, Maare C, Wassermann K. Cellular resistance to cancer chemotherapy. INTERNATIONAL REVIEW OF CYTOLOGY 1994; 156:77-157. [PMID: 7860220 DOI: 10.1016/s0074-7696(08)62253-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- T Skovsgaard
- Department of Oncology, University of Copenhagen, Herlev Hospital, Denmark
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279
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Butryn RK, Smith KS, Adams EG, Abraham I, Stackpole J, Sampson KE, Bhuyan BK. V79 Chinese hamster lung cells resistant to the bis-alkylator bizelesin are multidrug-resistant. Cancer Chemother Pharmacol 1994; 34:44-50. [PMID: 7513620 DOI: 10.1007/bf00686110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Bizelesin (U-77779) is a highly potent bis-alkylating antitumor agent that is effective against several tumor systems in vitro and in vivo. V79 cells that were 125- to 250-fold resistant to bizelesin developed after constant exposure to gradually increasing concentrations of the drug. Resistant cells exhibited a multidrug-resistant phenotype and genotype as indicated by cross-resistant to several structurally and functionally unrelated drugs, e.g., colchicine, actinomycin D, and Adriamycin, and overexpression of mdr mRNA. Very low levels of cross-resistance to the alkylating agents cisplatin and melphalan were seen. Multidrug-resistant mouse leukemia (P388/Adriamycin-resistant) and human (KB/vinblastine-resistant) cells were also resistant to bizelesin. Bizelesin resistance was unstable and decreased when cells were grown in the absence of the drug. Resistant and sensitive cell lines had similar levels of glutathione, and bizelesin cytotoxicity for resistant cells was not markedly affected by treatment with buthionine sulfoximine. Cross-resistance between bizelesin and several of its analogs is reported.
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Affiliation(s)
- R K Butryn
- Department of Cancer and Infectious Diseases Research, Upjohn Company, Kalamazoo, MI 49001
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280
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Abstract
Multidrug resistance represents a major obstacle in the successful therapy of neoplastic diseases. Studies have demonstrated that this form of drug resistance occurs in cultured tumor cell lines as well as in human cancers. P-glycoprotein appears to play an important role in such cells by acting as an energy-dependent efflux pump to remove various natural-product drugs from the cell before they have a chance to exert their cytotoxic effects. Using the tools of molecular biology, studies are beginning to reveal the true incidence of multidrug resistance, as mediated by the MDR1 gene, in the clinical setting. It has been demonstrated, at least in the laboratory, that resistance mediated by P-glycoprotein may be modulated by a wide variety of compounds, including verapamil and cyclosporine A. These are compounds which, by themselves, generally have little or no effect on the tumor cells, but when used in conjunction with antineoplastic agents act to decrease, and in some instances eliminate, drug resistance. The mechanism(s) by which these agents act to reverse resistance is not fully understood. Clinical trials to modulate P-glycoprotein activity are now under way to determine whether such strategies will be feasible. The detection of the P-glycoprotein in patient samples is very important in the design of these studies, as it appears that drug-resistant cells lacking P-glycoprotein will be unaffected by agents such as verapamil. Clinical studies are needed in which patients are stratified into chemotherapy protocols based on levels of MDR1 mRNA or P-glycoprotein expression in the primary tumors. Several research areas have been identified that are important to the transfer of the discovery of the MDR1 gene and its protein product from the research laboratory to the clinical environment. There is an immediate need for comprehensive information on the prevalence and levels of expression of the human MDR genes and their protein products in human organs and tissues. Data are needed on P-glycoprotein levels in specific subpopulations (e.g., according to age, sex, race, and diet), and the study of the heterogeneity and variability of expression of P-glycoprotein in normal human tissues should be given high priority. Since early studies have indicated some successes in identifying patients with classic multidrug resistance who might be responsive to chemosensitization, it can be anticipated that clinical research will accelerate in this area. The next wave of clinical studies will provide clinical investigators with opportunities to develop and evaluate P-glycoprotein tests and correlate test results with clinical outcomes.
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Affiliation(s)
- W T Bellamy
- Department of Pathology, University of Arizona, Tucson 85724
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281
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/physiology
- ATP-Binding Cassette Transporters/physiology
- Amino Acid Sequence
- Animals
- Antineoplastic Agents/pharmacology
- Biological Transport, Active
- Cricetinae
- Drug Resistance, Multiple/genetics
- Gene Expression Regulation, Neoplastic/drug effects
- Glycosylation
- Humans
- Mice
- Models, Molecular
- Molecular Sequence Data
- Mutation
- Neoplasm Proteins/chemistry
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- Neoplasms/drug therapy
- Neoplasms/genetics
- Phosphorylation
- Protein Processing, Post-Translational
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Affiliation(s)
- L M Greenberger
- Lederle Laboratories, Department of Oncology and Tumor Immunology, Pearl River, NY 07666
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282
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Abstract
Resistance to chemotherapy is the single most important reason for treatment failure in cancer patients. Over the past 15 years, we have gained significant insight into one of the mechanisms responsible for this process: multidrug resistance (MDR). Far from being a phenomenon limited to the laboratory, multidrug resistance has been identified in a wide variety of newly diagnosed and recurrent human tumors. A number of compounds can block p-glycoprotein and overcome MDR in vitro and in vivo. Current strategies to block MDR are discussed in this review. Future research in this area will focus on the identification of more selective and potent MDR reversing agents and the development of entirely new approaches to overcoming multidrug resistance such as monoclonal antibodies, immunotoxins, and gene therapy.
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Affiliation(s)
- N H Patel
- Clinical Pharmacy Program, University of Texas Health Science Center, San Antonio 78284-7884
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283
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Butler RN, Butler WJ, Moraby Z, Fettman MJ, Khoo KK, Roberts-Thomson IC. Glutathione concentrations and glutathione S-transferase activity in human colonic neoplasms. J Gastroenterol Hepatol 1994; 9:60-3. [PMID: 8155868 DOI: 10.1111/j.1440-1746.1994.tb01217.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Tissue concentrations of glutathione (GSH) and the activity of glutathione S-transferases (GST) are relevant to the inactivation of a variety of xenobiotics including carcinogens and anti-neoplastic drugs. In this study, GSH concentrations and GST activity were determined in 25 adenomatous polyps removed at colonoscopy, and in cancer and uninvolved 'normal' mucosa from 58 operative specimens containing colon cancer. We also examined the relationship between GSH concentrations, GST activity and rates of cell proliferation as assessed by flow cytometry. Concentrations of GSH were significantly higher in adenomas (P = 0.001) and cancer (P = 0.001) than in uninvolved mucosa while GST activity was significantly higher in cancer (P = 0.007). There was a positive relationship between GSH concentrations and GST activity in adenomas (P = 0.001) but not in uninvolved mucosa (P = 0.06) or cancer (P = 0.4). Concentrations of GSH and GST activity were independent of results from flow cytometry. The higher concentrations of GSH in colonic neoplasms and the raised activity of GST in cancer may contribute to their resistance to anti-neoplastic drugs.
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Affiliation(s)
- R N Butler
- Department of Gastroenterology, Queen Elizabeth Hospital, Woodville, Australia
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284
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Tanaka S, Aizawa K, Katayanagi N, Tanaka O. Flow cytometric analysis of early steps in development of adriamycin resistance in a human gastric cancer cell line. Jpn J Cancer Res 1994; 85:86-92. [PMID: 7906264 PMCID: PMC5919343 DOI: 10.1111/j.1349-7006.1994.tb02890.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have established a low-level adriamycin (ADM)-resistant human gastric cancer cell line (MKN45R) from the parental cell line (MKN45) by exposure to stepwise increases of ADM concentration (final concentration, 0.026 microgram/ml). The purpose of this study was to identify the early steps in the development of ADM resistance in MKN45R by flow cytometric (FCM) analysis. Comparison of the concentration required for 50% growth inhibition, determined by a tetrazolium-based colorimetric assay, showed that MKN45R was about 2.6-fold more resistant to ADM than MKN45. However, the inhibition index values were 89.5% for MKN45 and 86.4% for MKN45R, respectively, showing that ADM was judged to be "effective" against both cell lines. On the other hand, cell kinetic analysis by FCM revealed that the increase of the ratio of G2M accumulation induced by ADM treatment was significantly lower (P < 0.01) in MKN45R. Moreover, the efflux of ADM estimated by FCM analysis was significantly increased (P < 0.05) in MKN45R even though there was no significant increase of P-glycoprotein expression. These results suggest that although ADM was still effective based on a standard drug sensitivity test, the cancer cells were already acquiring resistance to ADM as judged from FCM analysis. Moreover, the mechanism of this ADM resistance is considered to be independent of P-glycoprotein expression. Thus, FCM analysis is useful for detecting the early steps in the development of drug resistance of cancer cells.
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Affiliation(s)
- S Tanaka
- Department of Surgery I. Niigata University School of Medicine
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285
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Mülder HS, van Grondelle R, Westerhoff HV, Lankelma J. A plasma membrane 'vacuum cleaner' for daunorubicin in non-P-glycoprotein multidrug-resistant SW-1573 human non-small cell lung carcinoma cells. A study using fluorescence resonance energy transfer. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 218:871-82. [PMID: 8281939 DOI: 10.1111/j.1432-1033.1993.tb18443.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A multidrug resistant (MDR) human non-small cell lung carcinoma cell line, SW-1573/2R120 (2R120), not containing the drug-efflux pump P-glycoprotein (PgP), has been studied for the transport of daunorubicin (DN) across the cellular plasma membrane. Earlier, reduced initial DN-uptake rates and lower cellular DN steady-state concentrations were found for this cell line, when it was compared to the SW-1573 wild-type cell line. This finding was an indication for the presence of another cellular drug-efflux pump. However, we found similar DN-efflux rates in drug-free medium for the two cell lines, while for Pgp-containing MDR SW-1573/2R160 (2R160) cells the efflux rate was increased compared to wild-type cells. In order to elucidate differences in DN transport across the cellular plasma membrane, the association of DN with plasma membranes of intact cells was investigated, using fluorescence-resonance-energy transfer. For this purpose, the plasma-membrane probe 1-(4-trimethyl-ammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) was chosen since, because of the overlap between the emission spectrum of TMA-DPH and the excitation spectrum of DN, transfer of energy can be achieved from TMA-DPH to DN. Cells were loaded with TMA-DPH and, after addition of 10 microM DN, the TMA-DPH fluorescence was quenched. Rapid initial quenching proved to be similar in the MDR 2R160 (Pgp-containing) cells and in the SW-1573 wild-type cells (21 +/- 1% and 20 +/- 2%, respectively), but was less in the MDR 2R120 cells not containing Pgp (14 +/- 1%). This finding correlated with a lowered amount of DN dissolved in the plasma membrane of 2R120 cells. We interpret these data to be the result of a 'vacuum-cleaner' pumping system other than Pgp which removes DN from a plasma membrane compartment and equilibrates relatively slowly with the interior of the cell.
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Affiliation(s)
- H S Mülder
- Department of Oncology, Free University Hospital, Amsterdam, The Netherlands
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286
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Lepage P, Devault A, Gros P. Activation of the mouse mdr3 gene by insertion of retroviruses in multidrug-resistant P388 tumor cells. Mol Cell Biol 1993; 13:7380-92. [PMID: 8246958 PMCID: PMC364809 DOI: 10.1128/mcb.13.12.7380-7392.1993] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In multidrug-resistant (MDR) derivatives of the mouse lymphoid tumor P388, the emergence of MDR is associated with overexpression and transcriptional activation of the mdr3 gene, either in the absence of (P388/VCR-10) or concomitant with (P388/ADM-2) gene amplification. In both instances, Northern (RNA) blotting analyses have suggested the presence of altered mdr3 transcripts in these cells, possibly originating from novel transcription initiation sites. The mechanisms underlying mdr3 overexpression in these cells have been investigated. In P388/VCR-10 cells, Southern blotting analyses together with genomic DNA cloning and nucleotide sequencing have demonstrated the presence of an intact mouse mammary tumor virus (MMTV) within the boundaries of intron 1 of mdr3. cDNA cloning and nucleotide sequencing indicated that this integration event results in the synthesis and overexpression of a hybrid MMTV-mdr3 mRNA which initiates within the U3 region of the 5' long terminal repeat (LTR) of the provirus. Consequently, this mRNA lacks the normal exon 1 of mdr3 but contains (i) MMTV LTR-derived sequences at its 5' end, (ii) a novel mdr3 exon, mapping within the boundaries of intron 1 downstream of the MMTV integration site and generated by alternative splicing, and (iii) an otherwise intact 3' portion of mdr3 starting at exon 2. A similar type of analysis of P388/ADM-2 cells revealed that mdr3 overexpression in these cells is associated with the integration of an intracisternal A particle (IAP) within an L1Md repetitive element, immediately upstream of mdr3. The IAP insertion results in the overexpression of hybrid IAP-mdr3 mRNA transcripts that initiate within the 3' LTR of the IAP and which contain IAP LTR-derived sequences at the 5' end spliced 14 nucleotides upstream of the normal exon 1 of mdr3. Taken together, these results indicate that independent retroviral insertions were the initial mutagenic event responsible for mdr3 overexpression and survival during drug selection of these cell lines. Amplification of the rearranged and activated mdr3 gene copy occurred during further selection for high-level drug resistance in P388/ADM-2 cells.
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Affiliation(s)
- P Lepage
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
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287
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Abstract
Multidrug resistance hampers successful chemotherapy in many haematological neoplasms and is mediated by several cellular proteins. In some cases, the genes encoding these proteins have been shown to confer resistance on transfer to drug-sensitive cell lines. This is true for the efflux pump product of the MDR1 gene, P-170. Upregulation of enzymes such as GST has been observed, although the contribution of this enzyme in drug resistance expressed by malignant haematopoietic cells is still uncertain. Cells also appear to be able to downregulate enzymes which are drug targets. Examples include the decrease in Topo II which accompanies the resistance shown by cells to VP-16 and VM-26. Although many reports include both presentation and relapsed patients, there are few data on samples drawn from the same patients before and after chemotherapy. While P-170 and GST appear to be raised more often in cells from resistant and relapsed disease, it is quite clear that such mechanisms can be active in de novo malignancy and do not necessarily emerge as a consequence of prior chemotherapy. Methods of detecting drug resistance are reviewed here; these include in vitro cellular assays for drug toxicity, and molecular, immunological and functional detection of P-170 or Topo II. The clinical evaluation of such assays is only just beginning and some of the data are contradictory. To some extent, this may reflect the complex way in which the various resistance mechanisms may interact. Nevertheless, there are some encouraging early signs that the application of these assays to clinical material will yield valuable data on the relative contributions of these mechanisms and on ways in which they may be overcome. At present, much attention has focused on the potential of agents which prevent the P-170 efflux pump from exporting cytotoxics from the cell. This is likely to be only the first of new therapies arising from an improved understanding of multidrug resistance. More immediately, assays for multidrug resistance and its parameters may find their place as routine diagnostic and prognostic tools in the laboratory.
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Affiliation(s)
- P Baines
- Department of Haematology, University of Wales College of Medicine, Heath Park, Cardiff, UK
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288
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Brown PC, Thorgeirsson SS, Silverman JA. Cloning and regulation of the rat mdr2 gene. Nucleic Acids Res 1993; 21:3885-91. [PMID: 8103593 PMCID: PMC309915 DOI: 10.1093/nar/21.16.3885] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We have cloned the complete cDNA encoding the rat mdr2 gene by a combination of library screening and the polymerase chain reaction. The sequence of rat mdr2 cDNA is highly similar to other members of the mdr gene family but the initiation of transcription, tissue distribution and regulation of expression of rat mdr2 diverge from the other isoforms. Primer extension analysis showed rat mdr2 mRNA to have a major transcription start point at -277 and a minor one at approximately -518. We constructed gene specific probes for rat mdr2 and mdr1b and compared the expression patterns of these two genes. The highest expression of mdr2 mRNA was in the muscle, heart, liver and spleen. Both mdr2 and 1b mRNA levels were elevated in the livers of rats treated with CCl4 or following partial hepatectomies although the time course of induction of each gene differed. Mdr1b increased by 12 to 24 hours while mdr2 did not increase until 48 hours. Treatment of isolated hepatocytes or RC3 cells with cycloheximide did not effect mdr2 mRNA. In contrast, mdr1b expression was increased. These data suggest that rat mdr2, unlike mdr1b, is not regulated by a negative trans-acting protein factor.
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Affiliation(s)
- P C Brown
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20892
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289
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Li XK, Kobayashi H, Holland JF, Ohnuma T. Expression of dihydrofolate reductase and multidrug resistance genes in trimetrexate-resistant human leukemia cell lines. Leuk Res 1993; 17:483-90. [PMID: 8099375 DOI: 10.1016/0145-2126(93)90123-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Exposure of MOLT-3 human leukemic cells in culture to a lipophilic antifolate, trimetrexate (TMQ), resulted in the development of sublines resistant to antifolates as well as to drugs related to multidrug resistance. The TMQ-resistant sublines had an increase in dihydrofolate reductase (DHFR) activity and overexpression of P-glycoprotein. In these sublines, neither the DHFR gene nor the MDR1 gene were amplified. In these cells, DHFR transcripts were also not overexpressed but DHFR protein was increased, indicative of translational or post-translational control of DHFR activity. In contrast, MDR1 transcripts were found to be overexpressed, in parallel with P-glycoprotein production. Therefore, increases in P-glycoprotein appear controlled at the transcriptional level. These data support evidence that TMQ produced two phenotypic changes independently: the former probably from folate deficiency and the latter from the lipophilic nature of the compound.
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Affiliation(s)
- X K Li
- Department of Neoplastic Diseases, Mount Sinai Medical Center, New York, NY 10029
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290
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Chenivesse X, Franco D, Bréchot C. MDR1 (multidrug resistance) gene expression in human primary liver cancer and cirrhosis. J Hepatol 1993; 18:168-72. [PMID: 8409332 DOI: 10.1016/s0168-8278(05)80243-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
MDR1 RNA levels were analysed in patients with hepatocellular carcinoma (HCC), benign liver tumors or cirrhosis. None of the patients with HCC had received chemotherapy. MDR1 RNA levels were increased relative to a normal liver specimen in 15/26 liver cancers, 2/6 benign liver tumors and 0/8 tumor-free cirrhotic livers. MDR1 was also overexpressed in cirrhotic non-tumorous liver tissues of some patients with HCC. The results indicate that the MDR1 gene is overexpressed in liver tumors and some preneoplastic lesions and that might account for the very poor response of primary liver cancers to chemotherapy.
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291
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Campain JA, Padmanabhan R, Hwang J, Gottesman MM, Pastan I. Characterization of an unusual mutant of human melanoma cells resistant to anticancer drugs that inhibit topoisomerase II. J Cell Physiol 1993; 155:414-25. [PMID: 8097746 DOI: 10.1002/jcp.1041550224] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The topoisomerase II inhibitor, VP-16 (etoposide), is an important component in many chemotherapeutic regimens. To characterize resistance to this drug, the human melanoma cell line, FEM-X, was selected in multiple steps with VP-16. To prevent the development of typical multidrug resistance, an inhibitor of P-glycoprotein, the tiapamil analog, RO-11-2933, was added to the selections. The resultant clone FVP3 is 56-fold resistant to VP-16 and cross-resistant to doxorubicin (Adriamycin) (9-fold) and VM-26 (27-fold). These cells are also two- to four-fold resistant to m-AMSA, daunorubicin, and mitoxantrone. FVP3 is not resistant to the P-glycoprotein substrates vinblastine, does not express the MDR1 gene at detectable levels, and does not show reduced 3H-VP-16 accumulation. Unlike other cell lines that exhibit resistance to inhibitors of topoisomerase II, FVP3 has the same level of topoisomerase II expression and activity as FEM-X. Using live cells treated with VP-16, band depletion assays and KCI/SDS precipitation assays show that topoisomerase II from FVP3 is much less susceptible to drug-induced cleavable complex formation than is that from FEM-X. This difference in sensitivity to VP-16 is also detected using lysates from disrupted cells, but not with isolated nuclei devoid of cytoplasmic and membrane components. In addition, the topoisomerase II present in nuclear extracts from FVP3 is not resistant to the effects of VP-16 as measured by: (1) inhibition of strand passing activity during decatenation of kinetoplast DNA, (2) drug-induced linearization of plasmid DNA, and (3) immunodepletion by VP-16. These results suggest that some component of the cytoplasm or cellular membranes, or a factor depleted from nuclei during their isolation, is responsible for the resistance to VP-16 in FVP3.
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Affiliation(s)
- J A Campain
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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292
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Wunder JS, Bell RS, Wold L, Andrulis IL. Expression of the multidrug resistance gene in osteosarcoma: a pilot study. J Orthop Res 1993; 11:396-403. [PMID: 8100852 DOI: 10.1002/jor.1100110311] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Resistance to combination chemotherapy remains a challenge in the treatment of osteosarcoma yet has not been studied extensively in this tumour. One mechanism of multiple drug resistance is increased expression of the multidrug resistance gene (mdr1). The level of mdr1 messenger RNA (mRNA) expression has been found to correlate with the degree of drug resistance in a number of tumour cell lines in vitro, which suggests that it also may be useful as a predictor of similar resistance in vivo. Using a highly sensitive assay based on the polymerase chain reaction to measure the amount of mdr1 mRNA, we detected various levels of mdr1 expression in 18 osteosarcoma specimens from 15 patients with resectable nonmetastatic osteosarcoma. At follow-up at a minimum of 30 months later, a trend toward a worse outcome was observed in patients with tumours exhibiting high levels of mdr1 expression. The results of this pilot study suggest that a larger scale prospective investigation of the effect of mdr1 gene expression on outcome in osteosarcoma is warranted.
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Affiliation(s)
- J S Wunder
- Division of Orthopaedic Surgery, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
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293
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Nakamura S, Wakusawa S, Tajima K, Miyamoto K, Hagiwara M, Hidaka H. Effects of isoquinolinesulphonamide compounds on multidrug-resistant P388 cells. J Pharm Pharmacol 1993; 45:268-73. [PMID: 8098366 DOI: 10.1111/j.2042-7158.1993.tb05551.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effects of eight isoquinolinesulphonamide compounds on resistance to vinblastine in adriamycin-resistant mouse leukaemia cells (P388/ADR) which overexpress the relative molecular weight (M(r)) 140 kDa P-glycoprotein in the plasma membrane were investigated. N-[2-(Methylamino)ethyl]-5-isoquinolinesulphonamide (H-8) and N-(2-aminoethyl)-5-isoquinolinesulphonamide (H-9) did not reverse vinblastine resistance. N-[2-[N-[3-(4-Chlorophenyl)-2-propenyl]amino] ethyl]-5-isoquinolinesulphonamide (H-86) and N-[2-[N-[3-(4-chlorophenyl)-1-methyl-2-propenyl] amino]ethyl]-5-isoquinolinesulphonamide (H-87) caused accumulation of intracellular vinblastine and inhibition of vinblastine efflux from the cells and reversed the resistance. Addition of an aminoethyl group to the nitrogen atom of the sulphonamide group (W-66) or a formyl group at the terminal amino group (H-85) of H-86 reduced those activities. Conversion of the chlorophenyl group of H-87 to pyridinyl (H-31) or furanyl (H-34) markedly decreased activities against the drug resistance. The activity against vinblastine accumulation closely correlated with the apparent partition coefficient of compounds. These compounds dose-dependently inhibited photoaffinity labelling of a photosensitive analogue of vinblastine, N-(p-azido-(3-[125I)salicyl)-N'-beta-aminoethyl-vindesine ([125I]NASV), and there was a good correlation between inhibition of [125I]NASV-photolabelling and hydrophobicity. Although these isoquinolinesulphonamides inhibited protein kinase A with different magnitudes, this activity did not correlate with the effect on the drug resistance. These results indicate that isoquinolinesulphonamide compounds with a hydrophobic group interact with antitumour drugs on P-glycoprotein and reverse multidrug resistance without involvement of their activity on protein kinase A.
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Affiliation(s)
- S Nakamura
- Third Division, Hokuriku University, Kanazawa, Japan
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294
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Takatori T, Ogura M, Tsuruo T. Purification and characterization of NF-R2 that regulates the expression of the human multidrug resistance (MDR1) gene. Jpn J Cancer Res 1993; 84:298-303. [PMID: 8098026 PMCID: PMC5919146 DOI: 10.1111/j.1349-7006.1993.tb02870.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
NF-R2 is a DNA-binding protein that interacts with the MDR1 gene proximal promoter sequence. We previously reported that NF-R2 binds within the promoter's -126 and -102 regions, which contain the ATTCAGTCA motif. In the present study, we have purified NF-R2 from the nuclear extract of K562/ADM cells, a multidrug-resistant cell line derived from human myelogenous leukemia K562 cells, using sequential chromatography on Sephacryl S-300, DEAE-Sepharose, heparin-Sepharose and a DNA affinity column consisting of a repetitive synthetic ATTCAGTCA motif coupled to Sepharose. NF-R2 runs as a single protein of 75 kDa on SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). CAT (chloramphenicol acetyltransferase) expression assay and gel mobility shift competition assay with mutated promoters revealed that the ATTCAGTCA motif is a positive regulatory element of MDR1 gene and that the motif is important for NF-R2 binding. These results suggest that NF-R2 may be involved in the positive regulation of the MDR1 gene transcription.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Base Sequence
- Chloramphenicol O-Acetyltransferase/biosynthesis
- Chromatography, Affinity
- Chromatography, Gel
- Chromatography, Ion Exchange
- Drug Resistance/genetics
- Electrophoresis, Polyacrylamide Gel
- Gene Expression Regulation, Neoplastic
- Humans
- Leukemia, Myeloid/metabolism
- Membrane Glycoproteins/genetics
- Molecular Sequence Data
- Mutation
- Plasmids
- Promoter Regions, Genetic/genetics
- Regulatory Sequences, Nucleic Acid
- Sequence Homology, Nucleic Acid
- Trans-Activators/genetics
- Trans-Activators/isolation & purification
- Trans-Activators/physiology
- Transcription, Genetic/genetics
- Tumor Cells, Cultured
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Affiliation(s)
- T Takatori
- Institute of Applied Microbiology, University of Tokyo
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295
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Hoskins J, DeHerdt SV, Moore RE, Bumol TF. The development and characterization of Vinca alkaloid-resistant Caco-2 human colorectal cell lines expressing mdr-1. Int J Cancer 1993; 53:680-8. [PMID: 8094716 DOI: 10.1002/ijc.2910530426] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Several novel cell lines with variable resistance to Vinca alkaloids have been derived from the Caco-2 human colorectal carcinoma cell line. Parental Caco-2 cells were found by PCR analysis and immunofluorescence studies to produce a low amount of the mdr-1 gene product (P-glycoprotein) that may well be clinically significant. These cells, which were initially highly sensitive to desacetylvinblastine sulfate (DAVLB sulfate) were selected, without mutagenesis, through continuous culture with increasing concentrations of DAVLB sulfate over a 335-day period. This selection resulted in cell lines that displayed an mdr (multiple-drug-resistance) cross-resistance profile that could be reversed with agents such as verapamil and vindoline. During the selection process the amount of mdr-1 mRNA present, the extent of gene amplification and the amount of gp170 expressed all correlated well with the level of drug resistance. However, this correlation does not hold in the absence of selective pressure for the more resistant cell lines where gene amplification and the amount of P-glycoprotein present remained constant while the level of drug resistance and the amount of mdr-1 mRNA present declined. These cell lines are potential models for studying mdr-I gene expression and drug resistance in human epithelial malignancies.
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Affiliation(s)
- J Hoskins
- Department of Cancer Research, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285
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296
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van Groenigen M, Valentijn LJ, Baas F. Identification of a functional initiator sequence in the human MDR1 promoter. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1172:138-46. [PMID: 8094978 DOI: 10.1016/0167-4781(93)90280-q] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The sequence requirements for proper transcriptional initiation of the downstream human multidrug resistance MDR1 (P1) promoter were determined using a transient expression system in HeLa cells. The MDR1 promoter has no TATA box and the transcription start site has a strong homology with the initiator (Inr) sequence identified in the murine terminal deoxynucleotidyltransferase (TdT) gene. A deletion analysis showed that sequences from -6 to +11 relative to the P1 transcription start site were sufficient for proper transcriptional initiation, whereas deletion of sequences downstream of +11 resulted in a strong reduction of properly initiated transcripts. In this transient assay system, both the MDR1 and TdT initiator require in Hela cells the presence of an upstream activating sequence such as the SV40 enhancer. This is in contrast to the transcription in in vitro systems, in which the initiator sequence is able to direct transcription in the absence of an enhancer. Analysis of mutations in the initiator sequence from -8 to +10 showed that the A and T nucleotides at position +1 and +3, respectively, were essential, whereas other substitutions in this region had little effect on promoter activity.
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Affiliation(s)
- M van Groenigen
- Department of Neurology, Academic Medical Center, Amsterdam, Netherlands
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297
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Budd GT, Bukowski RM, Lichtin A, Bauer L, Van Kirk P, Ganapathi R. Phase II trial of doxorubicin and trifluoperazine in metastatic breast cancer. Invest New Drugs 1993; 11:75-9. [PMID: 8349440 DOI: 10.1007/bf00873916] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Pre-clinical and clinical studies have shown that trifluoperazine (TFP) can modulate multidrug resistance. We have performed a Phase II trial of TFP and doxorubicin in doxorubicin-naive patients with metastatic breast cancer. We hypothesized that TFP would inhibit the development of doxorubicin resistance, resulting in an increased rate of complete response or a prolongation in response duration. Twenty patients with metastatic breast cancer were treated every 3 weeks with TFP 5 mg by mouth every 6 hours on days 0-5 and doxorubicin 60 mg/m2/96 hr on days 1-4 by continuous intravenous infusion. The first 5 patients were treated with TFP 15 mg by mouth every 6 hours, but the dose was reduced to 5 mg every 6 hours when grade 3-4 extrapyramidal toxicity was noted in 3 of the first 5 patients. Thereafter, neurologic toxicity was grade 0-2. No complete and 9 partial responses were produced in 20 patients (45%). The median response duration was 17 weeks (range 7-112). The combination of trifluoperazine and doxorubicin did not seem to produce a response rate or duration markedly different than that expected for doxorubicin alone in patients with metastatic breast cancer. Alternative trial designs may be necessary in future clinical trials investigating the inhibition of acquisition of drug resistance.
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Affiliation(s)
- G T Budd
- Department of Hematology/Medical Oncology, Cleveland Clinic Foundation, OH 44195
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298
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Michieli M, Michelutti A, Damiani D, Pipan C, Raspadori D, Lauria F, Baccarani M. A comparative analysis of the sensitivity of multidrug resistant (MDR) and non-MDR cells to different anthracycline derivatives. Leuk Lymphoma 1993; 9:255-64. [PMID: 8097129 DOI: 10.3109/10428199309147379] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Because of the fact that tumor cell sensitivity to cytotoxic agents may play a major role in cancer treatment, and several anthracyclines are widely used for first-line treatment of leukemia, lymphoma and other tumors, and since the overexpression of the mdr-1 gene-coded 170 Kd glycoprotein (P170) decreases cell sensitivity to anthracyclines, we investigated the relationship between P170 overexpression and the cytotoxicity of two classic anthracyclines (Daunorubicin or DNR and Doxorubicin or DX) and two lipophilic anthracycline derivatives (Idarubicin or IDA and Iododoxorubicin or IDX). For these purposes, we used multidrug resistant (MDR) and non-MDR tumor and leukemia cell lines and the MTT-microcultured tetrazolium colorimetric assay. We showed that mdr-1 gene overexpression was strongly associated with the development of a high level of resistance to DNR and DX, but not to the derivatives IDA and IDX. These data suggest that more lipophilic anthracycline derivatives may also be active in MDR cell systems.
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Affiliation(s)
- M Michieli
- Section of Hematology, University of Udine School of Medicine, Italy
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299
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Ogura M, Takatori T, Tsuruo T. Purification and characterization of NF-R1 that regulates the expression of the human multidrug resistance (MDR1) gene. Nucleic Acids Res 1993; 20:5811-7. [PMID: 1360648 PMCID: PMC334420 DOI: 10.1093/nar/20.21.5811] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have purified a protein, NF-R1, that specifically binds to two unrelated motifs--the ATTCAGTCA motif and the GC-box motif--on the MDR1 proximal promoter. Purified NF-R1 has been confirmed by southwestern blotting to be a 110-kDa protein. Methylation interference analysis revealed that the nucleotides were in close contact with purified NF-R1 on the ATTCAGTCA and GC-box motifs. The nucleotides were required for the binding of NF-R1, as seen by competition gel mobility shift assay using point mutated oligonucleotides. In a CAT expression assay using the corresponding point-mutated MDR1 promoter fused to a CAT gene, binding inhibition of NF-R1 to the promoter resulted in 2- to 3-fold increases of CAT activity, as compared to the intact promoter in Adriamycin-resistant K562 cells. Thus NF-R1 has a relation to the negative regulation of the MDR1 gene transcription.
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Affiliation(s)
- M Ogura
- Institute of Applied Microbiology, University of Tokyo, Japan
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300
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Hill BT. Differing patterns of cross-resistance resulting from exposures to specific antitumour drugs or to radiation in vitro. Cytotechnology 1993; 12:265-88. [PMID: 7765329 DOI: 10.1007/bf00744668] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
This article reviews the patterns of cross-resistance identified in various P-glycoprotein-mediated and non-P-glycoprotein-mediated drug resistant mammalian tumour cell lines. The differing patterns of cross-resistance and the variable levels of resistance expressed are summarised and discussed. Although the mechanism by which P-glycoprotein can recognise and transport a large group of structurally-unrelated substrates remains to be defined, the recent evidence indicating that membrane associated domains participate in substrate recognition and binding is summarised, and other possible explanations for these variable cross-resistance patterns are considered. Amongst the non-P-glycoprotein-overexpressing multidrug resistant cell lines, two subsets are clearly identifiable, one lacking and the other expressing cross-resistance to the Vinca alkaloids. Resistance mechanisms implicated in these various sublines and possible explanations for their differing levels and patterns of cross-resistance are summarised. Clinical resistance is identified in patients following treatment not only with antitumour drugs, but also after radiotherapy. Experimental data providing a biological basis for this observation are summarised. A distinctive multiple drug resistance phenotype has been identified in tumour cells following exposure in vitro to fractionated X-irradiation characterised by: the expression of resistance to the Vinca alkaloids and the epipodophyllotoxins but not the anthracyclines and overexpression of P-glycoprotein which is post-translationally regulated, but without any concomitant overexpression of P-glycoprotein mRNA. Finally, the possible clinical relevance of these variable patterns of cross-resistance to the antitumour drugs commonly used in the clinic is considered.
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Affiliation(s)
- B T Hill
- Laboratory of Cellular Chemotherapy, Imperial Cancer Research Fund, London, UK
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