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Silva R, Vilas-Boas V, Carmo H, Dinis-Oliveira RJ, Carvalho F, de Lourdes Bastos M, Remião F. Modulation of P-glycoprotein efflux pump: induction and activation as a therapeutic strategy. Pharmacol Ther 2014; 149:1-123. [PMID: 25435018 DOI: 10.1016/j.pharmthera.2014.11.013] [Citation(s) in RCA: 231] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 11/19/2014] [Indexed: 01/03/2023]
Abstract
P-glycoprotein (P-gp) is an ATP-dependent efflux pump encoded by the MDR1 gene in humans, known to mediate multidrug resistance of neoplastic cells to cancer therapy. For several decades, P-gp inhibition has drawn many significant research efforts in an attempt to overcome this phenomenon. However, P-gp is also constitutively expressed in normal human epithelial tissues and, due to its broad substrate specificity, to its cellular polarized expression in many excretory and barrier tissues, and to its great efflux capacity, it can play a crucial role in limiting the absorption and distribution of harmful xenobiotics, by decreasing their intracellular accumulation. Such a defense mechanism can be of particular relevance at the intestinal level, by significantly reducing the intestinal absorption of the xenobiotic and, consequently, avoiding its access to the target organs. In this review, the current knowledge on this important efflux pump is summarized, and a new focus is brought on the therapeutic interest of inducing and/or activating P-gp for limiting the toxicity caused by its substrates. Several in vivo and in vitro studies validating the use of such a therapeutic strategy are discussed. An extensive literature search for reported P-gp inducers/activators and for the experimental models used in their characterization was conducted. Those studies demonstrate that effective antidotal pathways can be achieved by efficiently promoting the P-gp-mediated efflux of deleterious xenobiotics, resulting in a significant reduction in their intracellular levels and, consequently, in a significant reduction of their toxicity.
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Affiliation(s)
- Renata Silva
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Vânia Vilas-Boas
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Helena Carmo
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Ricardo Jorge Dinis-Oliveira
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; INFACTS - Institute of Research and Advanced Training in Health Sciences and Technologies, Department of Sciences, Advanced Institute of Health Sciences - North (ISCS-N), CESPU, CRL, Gandra, Portugal; Department of Legal Medicine and Forensic Sciences, Faculty of Medicine, University of Porto, Porto, Portugal.
| | - Félix Carvalho
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Maria de Lourdes Bastos
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Fernando Remião
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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2
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Arias A, Rigalli JP, Villanueva SSM, Ruiz ML, Luquita MG, Perdomo VG, Vore M, Catania VA, Mottino AD. Regulation of expression and activity of multidrug resistance proteins MRP2 and MDR1 by estrogenic compounds in Caco-2 cells. Role in prevention of xenobiotic-induced cytotoxicity. Toxicology 2014; 320:46-55. [PMID: 24685904 DOI: 10.1016/j.tox.2014.03.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/10/2014] [Accepted: 03/20/2014] [Indexed: 11/28/2022]
Abstract
ABC transporters including MRP2, MDR1 and BCRP play a major role in tissue defense. Epidemiological and experimental studies suggest a cytoprotective role of estrogens in intestine, though the mechanism remains poorly understood. We evaluated whether pharmacologic concentrations of ethynylestradiol (EE, 0.05pM to 5nM), or concentrations of genistein (GNT) associated with soy ingestion (0.1-10μM), affect the expression and activity of multidrug resistance proteins MRP2, MDR1 and BCRP using Caco-2 cells, an in vitro model of intestinal epithelium. We found that incubation with 5pM EE and 1μM GNT for 48h increased expression and activity of both MRP2 and MDR1. Estrogens did not affect expression of BCRP protein at any concentration studied. Irrespective of the estrogen tested, up-regulation of MDR1 and MRP2 protein was accompanied by increased levels of MDR1 mRNA, whereas MRP2 mRNA remained unchanged. Cytotoxicity assays demonstrated association of MRP2 and MDR1 up-regulation with increased resistance to cell death induced by 1-chloro-2,4-dinitrobenzene, an MRP2 substrate precursor, and by paraquat, an MDR1 substrate. Experiments using an estrogen receptor (ER) antagonist implicate ER participation in MRP2 and MDR1 regulation. GNT but not EE increased the expression of ERβ, the most abundant form in human intestine and in Caco-2 cells, which could lead in turn to increased sensitivity to estrogens. We conclude that specific concentrations of estrogens can confer resistance against cytotoxicity in Caco-2 cells, due in part to positive modulation of ABC transporters involved in extrusion of their toxic substrates. Although extrapolation of these results to the in vivo situation must be cautiously done, the data could explain tentatively the cytoprotective role of estrogens against chemical injury in intestine.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/drug effects
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP Binding Cassette Transporter, Subfamily G, Member 2
- ATP-Binding Cassette Transporters/drug effects
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Caco-2 Cells
- Dinitrochlorobenzene/toxicity
- Dose-Response Relationship, Drug
- Estrogen Antagonists/pharmacology
- Estrogen Receptor beta/genetics
- Ethinyl Estradiol/administration & dosage
- Ethinyl Estradiol/pharmacology
- Gene Expression Regulation/drug effects
- Genistein/administration & dosage
- Genistein/pharmacology
- Humans
- Intestinal Mucosa/drug effects
- Intestinal Mucosa/metabolism
- Multidrug Resistance-Associated Protein 2
- Multidrug Resistance-Associated Proteins/drug effects
- Multidrug Resistance-Associated Proteins/genetics
- Multidrug Resistance-Associated Proteins/metabolism
- Neoplasm Proteins/drug effects
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Paraquat/toxicity
- RNA, Messenger/metabolism
- Glycine max/chemistry
- Up-Regulation/drug effects
- Xenobiotics/toxicity
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Affiliation(s)
- Agostina Arias
- Instituto de Fisiología Experimental (IFISE-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Rosario, Santa Fe, Argentina
| | - Juan Pablo Rigalli
- Instituto de Fisiología Experimental (IFISE-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Rosario, Santa Fe, Argentina
| | - Silvina S M Villanueva
- Instituto de Fisiología Experimental (IFISE-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Rosario, Santa Fe, Argentina
| | - María L Ruiz
- Instituto de Fisiología Experimental (IFISE-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Rosario, Santa Fe, Argentina
| | - Marcelo G Luquita
- Instituto de Fisiología Experimental (IFISE-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Rosario, Santa Fe, Argentina
| | - Virginia G Perdomo
- Instituto de Fisiología Experimental (IFISE-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Rosario, Santa Fe, Argentina
| | - Mary Vore
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY, USA
| | - Viviana A Catania
- Instituto de Fisiología Experimental (IFISE-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Rosario, Santa Fe, Argentina
| | - Aldo D Mottino
- Instituto de Fisiología Experimental (IFISE-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Rosario, Santa Fe, Argentina.
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Frota MLCD, Klamt F, Dal-Pizzol F, Schiengold M, Moreira JCF. Retinol-inducedmdr1andmdr3 modulation in cultured rat Sertoli cells is attenuated by free radical scavengers. Redox Rep 2013; 9:161-5. [PMID: 15327746 DOI: 10.1179/135100004225005192] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The effects of retinol on modulation of mdr genes in Sertoli cells were investigated. The hypothesis that free radical scavengers may attenuate the effect of retinol was also tested. Sertoli cells isolated from 15-day-old Wistar rats were cultured for 48 h and then treated with retinol for 24 h with or without free radical scavengers (1 mM mannitol, 0.1 mM Trolox or superoxide dismutase [200 U/ml]). Expression of mdr1, mdr2 and mdr3 genes was monitored by RT-PCR. Mitochondrial superoxide production was used as an index of ROS production. Expression of mdr1 and mdr3 was inhibited by retinol treatment (7 microM, 24 h), while mdr2 was not detected in response to any of the treatments. We also observed that retinol supplementation (7 microM, 24 h) increased superoxide production. The observed inhibition of mdr genes was attenuated by all co-treatments, suggesting that retinol-induced ROS are required for inhibition of mdr1 and mdr3 expression. The results suggest that retinol may play an important role in the modulation of the mdr gene family in cultured rat Sertoli cells and that these effects appear to be mediated by ROS.
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4
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Iqbal M, Ho HL, Petropoulos S, Moisiadis VG, Gibb W, Matthews SG. Pro-inflammatory cytokine regulation of P-glycoprotein in the developing blood-brain barrier. PLoS One 2012; 7:e43022. [PMID: 22973436 PMCID: PMC3433182 DOI: 10.1371/journal.pone.0043022] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 07/16/2012] [Indexed: 01/16/2023] Open
Abstract
Placental P-glycoprotein (P-gp) acts to protect the developing fetus from exogenous compounds. This protection declines with advancing gestation leaving the fetus and fetal brain vulnerable to these compounds and potential teratogens in maternal circulation. This vulnerability may be more pronounced in pregnancies complicated by infection, which is common during pregnancy. Pro-inflammatory cytokines (released during infection) have been shown to be potent inhibitors of P-gp, but nothing is known regarding their effects at the developing blood-brain barrier (BBB). We hypothesized that P-gp function and expression in endothelial cells of the developing BBB will be inhibited by pro-inflammatory cytokines. We have derived brain endothelial cell (BEC) cultures from various stages of development of the guinea pig: gestational day (GD) 50, 65 (term ∼68 days) and postnatal day (PND) 14. Once these cultures reached confluence, BECs were treated with various doses (100–104 pg/mL) of pro-inflammatory cytokines: interleukin-1β (IL-1β), interleukin-6 (IL-6) or tumor necrosis factor- α (TNF-α). P-gp function or abcb1 mRNA (encodes P-gp) expression was assessed following treatment. Incubation of GD50 BECs with IL-1β, IL-6 or TNF-α resulted in no change in P-gp function. GD65 BECs displayed a dose-dependent decrease in function with all cytokines tested; maximal effects at 42%, 65% and 34% with IL-1β, IL-6 and TNF-α treatment, respectively (P<0.01). Inhibition of P-gp function by IL-1β, IL-6 and TNF-α was even greater in PND14 BECs; maximal effects at 36% (P<0.01), 84% (P<0.05) and 55% (P<0.01), respectively. Cytokine-induced reductions in P-gp function were associated with decreased abcb1 mRNA expression. These data suggest that BBB P-gp function is increasingly responsive to the inhibitory effects of pro-inflammatory cytokines, with increasing developmental age. Thus, women who experience infection and take prescription medication during pregnancy may expose the developing fetal brain to greater amounts of exogenous compounds – many of which are considered potentially teratogenic.
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Affiliation(s)
- Majid Iqbal
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
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5
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Abstract
BACKGROUND The ER chaperone GRP78/BiP is a homolog of the Hsp70 family of heat shock proteins, yet GRP78/BiP is not induced by heat shock but instead by ER stress. However, previous studies had not considered more physiologically relevant temperature elevation associated with febrile hyperthermia. In this report we examine the response of GRP78/BiP and other components of the ER stress pathway in cells exposed to 40°C. METHODOLOGY AD293 cells were exposed to 43°C heat shock to confirm inhibition of the ER stress response genes. Five mammalian cell types, including AD293 cells, were then exposed to 40°C hyperthermia for various time periods and induction of the ER stress pathway was assessed. PRINCIPAL FINDINGS The inhibition of the ER stress pathway by heat shock (43°C) was confirmed. In contrast cells subjected to more mild temperature elevation (40°C) showed either a partial or full ER stress pathway induction as determined by downstream targets of the three arms of the ER stress pathway as well as a heat shock response. Cells deficient for Perk or Gcn2 exhibit great sensitivity to ER stress induction by hyperthermia. CONCLUSIONS The ER stress pathway is induced partially or fully as a consequence of hyperthermia in parallel with induction of Hsp70. These findings suggest that the ER and cytoplasm of cells contain parallel pathways to coordinately regulate adaptation to febrile hyperthermia associated with disease or infection.
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6
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Castro J, Ribó M, Puig T, Colomer R, Vilanova M, Benito A. A cytotoxic ribonuclease reduces the expression level of P-glycoprotein in multidrug-resistant cell lines. Invest New Drugs 2011; 30:880-8. [PMID: 21286781 DOI: 10.1007/s10637-011-9636-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 01/20/2011] [Indexed: 10/18/2022]
Abstract
We have previously described a cytotoxic human pancreatic-ribonuclease variant, named PE5, which is able to cleave nuclear RNA, inducing the apoptosis of cancer cells. We have investigated whether PE5 could specifically inhibit the accumulation of P-glycoprotein in multidrug-resistant cells, since P-glycoprotein overexpression is one of the most important mechanisms contributing to the multiple drug resistance phenotype. We show that PE5 is able to reduce the amount of P-glycoprotein in two different multidrug-resistant cell lines, NCI/H460-R and NCI/ADR-RES, while glutathione S-transferase-л is not affected. We also show that onconase, an amphibian ribonuclease that is undergoing phase II/III clinical trials as an antitumor drug, does not affect the expression of these proteins. The reduction of P-glycoprotein accumulation, which has been functionally confirmed by flow cytometry analysis, may be caused by the previously reported underphosphorylation of JNK induced by PE5. We also show that PE5 has synergistic cytotoxicity with doxorubicin on the NCI/ADR-RES multidrug-resistant cell line. In conclusion, PE5 is a cytotoxic ribonuclease that cleaves nuclear RNA and decreases the expression of P-glycoprotein, showing anticancer activity in multidrug-resistant cell lines.
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Affiliation(s)
- Jessica Castro
- Laboratori d'Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Campus de Montilivi, Maria Aurèlia Campmany, 69, 17071, Girona, Spain
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7
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Chiarini F, Del Sole M, Mongiorgi S, Gaboardi GC, Cappellini A, Mantovani I, Follo MY, McCubrey JA, Martelli AM. The novel Akt inhibitor, perifosine, induces caspase-dependent apoptosis and downregulates P-glycoprotein expression in multidrug-resistant human T-acute leukemia cells by a JNK-dependent mechanism. Leukemia 2008; 22:1106-16. [PMID: 18385752 DOI: 10.1038/leu.2008.79] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A significant impediment to the success of cancer chemotherapy is the occurrence of multidrug resistance, which, in many cases, is attributable to overexpression of membrane transport proteins, such as the 170-kDa P-glycoprotein (P-gp). Also, upregulation of the phosphatidylinositol 3-kinase (PI3K)/Akt-signaling pathway is known to play an important role in drug resistance, and has been implicated in the aggressiveness of a number of different cancers, including T-acute lymphoblastic leukemia (T-ALL). We have investigated the therapeutic potential of the novel Akt inhibitor, perifosine (a synthetic alkylphospholipid), on human T-ALL CEM cells (CEM-R), characterized by both overexpression of P-gp and constitutive upregulation of the PI3K/Akt network. Perifosine treatment induced death by apoptosis in CEM-R cells. Apoptosis was characterized by caspase activation, Bid cleavage and cytochrome c release from mitochondria. The proapoptotic effect of perifosine was in part dependent on the Fas/FasL interactions and c-Jun NH(2)-terminal kinase (JNK) activation, as well as on the integrity of lipid rafts. Perifosine downregulated the expression of P-gp mRNA and protein and this effect required JNK activity. Our findings indicate that perifosine is a promising therapeutic agent for treatment of T-ALL cases characterized by both upregulation of the PI3K/Akt survival pathway and overexpression of P-gp.
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Affiliation(s)
- F Chiarini
- Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Università, di Bologna, Bologna, Italy
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8
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Choi BH, Kim CG, Lim Y, Shin SY, Lee YH. Curcumin down-regulates the multidrug-resistance mdr1b gene by inhibiting the PI3K/Akt/NF kappa B pathway. Cancer Lett 2008; 259:111-8. [PMID: 18006147 DOI: 10.1016/j.canlet.2007.10.003] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2007] [Revised: 09/30/2007] [Accepted: 10/03/2007] [Indexed: 12/18/2022]
Abstract
Curcumin, a constituent of turmeric, has anti-inflammatory, anti-carcinogenic, and chemopreventive effects in several animal tumor models. The expression of P-glycoprotein (P-gp), encoded by the mdr gene, is often associated with multidrug resistance (MDR) to unrelated chemotherapeutic drugs in cancer cells. Here, we demonstrate that curcumin down-regulates P-gp expression in multidrug-resistant L1210/Adr cells. Transfection with a series of 5'-deleted constructs of the mdr1b gene promoter indicated that a proximal region between -205 and +42 of the sequence was responsible for the suppression of promoter activity by curcumin. This response might be associated with the inhibition of the phosphatidyinositol 3-kinase (PI3K)/Akt/nuclear factor-kappa B (NF-kappa B) signaling pathway by curcumin. Moreover, curcumin reversed the MDR of the L1210/Adr cells. Thus, curcumin can contribute to the reversal of the MDR phenotype, probably due to the suppression of P-gp expression via the inhibition of the PI3K/Akt/NF-kappa B signaling pathway.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/genetics
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- Animals
- Antibiotics, Antineoplastic/pharmacology
- Antineoplastic Agents, Phytogenic/pharmacology
- Antineoplastic Agents, Phytogenic/therapeutic use
- Cell Line, Tumor
- Curcumin/pharmacology
- Curcumin/therapeutic use
- Dose-Response Relationship, Drug
- Down-Regulation
- Doxorubicin/pharmacology
- Drug Resistance, Multiple/drug effects
- Drug Resistance, Neoplasm/drug effects
- Gene Expression Regulation, Neoplastic/drug effects
- Leukemia L1210/drug therapy
- Leukemia L1210/enzymology
- Leukemia L1210/metabolism
- Mice
- NF-kappa B/antagonists & inhibitors
- NF-kappa B/metabolism
- NIH 3T3 Cells
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphoinositide-3 Kinase Inhibitors
- Promoter Regions, Genetic/drug effects
- Protein Kinase Inhibitors/pharmacology
- Protein Kinase Inhibitors/therapeutic use
- Proto-Oncogene Proteins c-akt/metabolism
- Sequence Deletion
- Signal Transduction/drug effects
- Transcription, Genetic/drug effects
- Transfection
- ATP-Binding Cassette Sub-Family B Member 4
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Affiliation(s)
- Byeong Hyeok Choi
- Department of Biomedical Science and Technology, IBST, Konkuk University, Seoul 143-701, Republic of Korea
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9
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Liu M, Li D, Aneja R, Joshi HC, Xie S, Zhang C, Zhou J. PO2-dependent Differential Regulation of Multidrug Resistance 1 Gene Expression by the c-Jun NH2-terminal Kinase Pathway. J Biol Chem 2007; 282:17581-6. [PMID: 17452336 DOI: 10.1074/jbc.m702206200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hypoxia-induced multidrug resistance 1 (MDR1) gene expression is known to be mediated by c-Jun NH(2)-terminal kinase (JNK) activation. However, the molecular mechanisms underlying this action of JNK remain elusive. On the contrary, there has been increasing evidence for a negative correlation of JNK activity with MDR1 expression under normoxic conditions. Here, we present evidence that the JNK pathway represses MDR1 expression in normoxia and activates MDR1 expression in hypoxia. Our data show that JNK pathway-induced MDR1 repression in normoxia is mediated by increased c-Jun binding to activator protein 1 site, located in the MDR1 promoter, and requires the activity of histone deacetylase 5. In contrast, JNK pathway-induced MDR1 activation in hypoxia is independent of the activator protein 1 site. Rather, this action is dependent on increased hypoxia-inducible factor 1 (HIF1) binding to the hypoxia response element in the MDR1 promoter, which is promoted by the interaction of HIF1alpha with c-Jun in the nucleus and requires the activity of the p300/CBP (CREB-binding protein) coactivator.
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Affiliation(s)
- Min Liu
- Department of Genetics and Cell Biology, Key Laboratory of Bioactive Materials (Ministry of Education), College of Life Sciences, Nankai University, Tianjin 300071, China
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10
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Zhou J, Liu M, Aneja R, Chandra R, Lage H, Joshi HC. Reversal of P-glycoprotein-mediated multidrug resistance in cancer cells by the c-Jun NH2-terminal kinase. Cancer Res 2006; 66:445-52. [PMID: 16397260 DOI: 10.1158/0008-5472.can-05-1779] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A significant impediment to the success of cancer chemotherapy is multidrug resistance (MDR). A typical form of MDR is attributable to the overexpression of membrane transport proteins, such as P-glycoprotein, resulting in an increased drug efflux. In this study, we show that adenovirus-mediated enhancement of the c-Jun NH2-terminal kinase (JNK) reduces the level of P-glycoprotein in a dose- and time-dependent manner. Protein turnover assay shows that the decrease of P-glycoprotein is independent of its protein stability. Instead, this occurs primarily at the mRNA level, as revealed by reverse transcription-PCR analysis. We find that P-glycoprotein down-regulation requires the catalytic activity of JNK and is mediated by the c-Jun transcription factor, as either pharmacologic inhibition of JNK activity or dominant-negative suppression of c-Jun remarkably abolishes the ability of JNK to down-regulate P-glycoprotein. In addition, electrophoretic mobility shift assay reveals that adenoviral JNK increases the activator protein binding activity of the mdr1 gene in the MDR cells. We further show that the decrease of P-glycoprotein level is associated with a significant increase in intracellular drug accumulation and dramatically enhances the sensitivity of MDR cancer cells to chemotherapeutic agents. Our study provides the first direct evidence that enhancement of the JNK pathway down-regulates P-glycoprotein and reverses P-glycoprotein-mediated MDR in cancer cells.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Adenoviridae/enzymology
- Adenoviridae/genetics
- Antibiotics, Antineoplastic/pharmacokinetics
- Antibiotics, Antineoplastic/pharmacology
- Cell Line, Tumor
- Daunorubicin/pharmacokinetics
- Daunorubicin/pharmacology
- Down-Regulation
- Drug Resistance, Multiple/physiology
- Drug Resistance, Neoplasm
- Humans
- JNK Mitogen-Activated Protein Kinases/biosynthesis
- JNK Mitogen-Activated Protein Kinases/genetics
- JNK Mitogen-Activated Protein Kinases/metabolism
- Pancreatic Neoplasms/drug therapy
- Pancreatic Neoplasms/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Stomach Neoplasms/drug therapy
- Stomach Neoplasms/metabolism
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Affiliation(s)
- Jun Zhou
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, China.
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11
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Abstract
P-glycoprotein, the founding member of the ATP-binding cassette (ABC) family of drug transporters, was first identified almost three decades ago and shown to confer resistance to multiple chemotherapeutic agents when overexpressed in human tumors. Subsequent years have witnessed a tremendous effort to characterize the function and regulation of P-glycoprotein, initially spurred by the hope that its inhibition was the key to overcoming clinical resistance to multiple anticancer agents. However, the identification of MRP1, another member of the ABC drug transporter family, led to the realization that the multidrug resistance (MDR) phenotype is considerably more complex than initially believed. Indeed, at the present time at least 10 members of the ABC transporter family have been implicated in an MDR phenotype, and it is likely that more will be added to this list as studies progress. With this complexity comes the imperative to improve our understanding of the function of individual transporters, as well as to delineate the mechanisms underlying their expression in normal and tumor cells, particularly those that may be amenable to therapeutic intervention. Several articles within this volume address the structure and function of drug transporters. This review will focus on our current understanding of the regulation of ABC drug transporters at the level of transcription.
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Affiliation(s)
- Kathleen W Scotto
- Department of Pharmacology, Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, PA 19111, USA.
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12
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Wartenberg M, Fischer K, Hescheler J, Sauer H. Redox regulation of P-glycoprotein-mediated multidrug resistance in multicellular prostate tumor spheroids. Int J Cancer 2000. [DOI: 10.1002/(sici)1097-0215(20000115)85:2<267::aid-ijc19>3.0.co;2-h] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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13
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Abstract
The emergence of resistance in a tumor population is most often associated with a disregulation of gene expression, usually at the level of transcription. A major goal in the field of cancer chemotherapy is to define the mechanisms underlying transcriptional regulation of drug resistance genes in an effort to identify targets for therapeutic intervention. Recently, considerable progress has been made in identifying the molecular mechanisms involved in the transcriptional regulation of the P-glycoprotein (Pgp) gene. When overexpressed in tumor cells, Pgp confers resistance to a variety of chemotherapeutic agents; this resistance has been termed MDR (multidrug resistance). Moreover, Pgp is a normal component of a variety of highly differentiated cell types and, as such, is regulated by both internal and external environmental stimuli. In this review, we will discuss the current knowledge regarding the DNA elements and protein factors involved in both constitutive and inducible regulation of Pgp transcription in normal and tumor cells.
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Affiliation(s)
- K W Scotto
- Memorial Sloan-Kettering Cancer Center, Program in Molecular Pharmacology and Experimental Therapeutics, 1275 York Avenue, New York, NY, 10021, U.S.A.,
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14
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Abstract
1. P-glycoprotein (P-gp) is a transmembrane protein involved in ATP-dependent efflux of various structurally unrelated anticancer drugs. Its overexpression in cancer cells decreases intracellular drug concentrations and, thus, confers a multidrug resistance phenotype. 2. P-gp is encoded by MDR genes, which constitute a small gene family comprising two genes in humans and three genes in rodents. Only the MDR1 gene in humans and mdr1 and mdr3 genes in rodents have been demonstrated to be involved in drug resistance. 3. P-gp encoded by the human MDR1 gene is a phosphorylated and glycosylated protein 1289 amino acids long, and consists of 2 halves that share a high degree of similarity. 4. A wide variety of cancers have been shown to express P-gp, including solid tumors and hematological malignancies. This P-gp positivity can be evidenced at the time of diagnosis prior to chemotherapy or at relapse after treatment, and has been correlated with treatment failure and poor prognosis in several types of cancer. In addition, P-gp is also expressed by some normal tissues, such as liver and kidney. 5. P-gp expression is regulated by various factors, including xenobiotics and hormones. 6. P-gp-mediated multidrug resistance can be reversed by various unrelated compounds called chemosensitizers or reversing agents. These drugs act through inhibition of P-gp function and have entered clinical trials.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- 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
- Animals
- Drug Resistance, Neoplasm
- Gene Expression Regulation
- Genes, MDR/physiology
- Humans
- Models, Structural
- Neoplasms/genetics
- Neoplasms/metabolism
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Affiliation(s)
- O Fardel
- INSERM U 49, Unité de Recherches Hépatologiques, Hôpital de Pontchaillou, Rennes, France
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15
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Reddy JC, Hosono S, Licht JD. The transcriptional effect of WT1 is modulated by choice of expression vector. J Biol Chem 1995; 270:29976-82. [PMID: 8530399 DOI: 10.1074/jbc.270.50.29976] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The WT1 Wilms' tumor suppressor gene encodes a zinc finger transcription factor which plays a critical role in renal and genitourinary development. The WT1 protein was reported to both activate and repress transcription. We found that the transcriptional effect of WT1 on the Egr1 promoter could be modulated by the use of expression vectors containing different promoters. WT1 activated the Egr1 promoter when expression of WT1 was driven by the Rous sarcoma virus promoter. In contrast, a cytomegalovirus (CMV) promoter-containing WT1 expression vector repressed the Egr1 promoter. However, WT1 activated transcription of a simple test promoter, EGR3tkCAT, regardless of the expression vector used. Co-transfection of the parental CMV-based vector strongly depressed the basal activity of the Egr1-CAT reporter, suggesting that the CMV promoter competes with the Egr1 promoter for transcription factors or co-factors which may be required for activation by WT1. In support of this hypothesis, WT1 was converted from an activator to a repressor by co-transfection of an excess of the parental CMV-based vector. These results provide an important caveat to the interpretation of co-transfection studies and confirm the bi-functional nature of the WT1 transcription factor.
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Affiliation(s)
- J C Reddy
- Brookdale Center for Molecular Biology, Mount Sinai School of Medicine, New York, New York 10029, USA
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16
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Schuetz JD, Strom SC, Schuetz EG. Induction of P-glycoprotein mRNA by protein synthesis inhibition is not controlled by a transcriptional repressor protein in rat and human liver cells. J Cell Physiol 1995; 165:261-72. [PMID: 7593204 DOI: 10.1002/jcp.1041650207] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Recent studies have suggested that a labile transcriptional repressor protein is important in the regulation of pgp mRNA expression. However, cycloheximide (CHX) the protein synthesis inhibitor used, can increase mRNAs by either stabilizing the mRNA transcript or directly activating gene transcription. To determine whether CHX posttranscriptionally increased pgp mRNA, we compared the effect of CHX, which inhibits protein synthesis by stabilizing polysomes, with puromycin (PURO), which inhibits protein synthesis by polysome destabilization. In rat hepatocytes, CHX induced pgp2 mRNA, and the increase was proportional to the degree of protein synthesis inhibition. In contrast, despite almost complete inhibition of protein synthesis, PURO did not induce pgp2 mRNA. Further studies demonstrated that PURO pretreatment could block pgp2 mRNA induction by CHX. Likewise, in cultures of primary human hepatocytes CHX, but not PURO, induced MDR1 mRNA. A polymerase chain reaction assay was developed to assess whether CHX treatment altered the length of the 3'-untranslated region (UTR) of pgp2. CHX treatment time dependently increased the length of the pgp2 3'-UTR. To determine whether CHX acts as a transcriptional agonist, we performed nuclear run-off analysis and found no increase in pgp2 gene transcription compared to untreated control. Further, transcription studies were performed by transiently transfecting HepG2 cells with plasmids containing 5' segments of human MDR1 fused with the reporter chloramphenicol acetyltransferase (CAT). These plasmids were not transcriptionally activated by CHX. In summary, our results cast doubt on the existence of a labile transcriptional repressor protein for pgp. Furthermore, these are the first studies to demonstrate that polysomal destabilization by PURO can block CHX induction of pgp.
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Affiliation(s)
- J D Schuetz
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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17
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Song R, Ikeguchi M, Zhou G, Kuo MT. Identification and characterization of a hepatoma cell-specific enhancer in the mouse multidrug resistance mdr1b promoter. J Biol Chem 1995; 270:25468-74. [PMID: 7592715 DOI: 10.1074/jbc.270.43.25468] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The expression of multidrug resistance/P-glycoprotein genes mdr1b(mdr1) and mdr1a(mdr3) is elevated during hepatocarcinogenesis. To investigate the regulation of mdr1b gene expression, we used transient transfection expression assays of reporter constructs containing various 5'-mdr1b flanking sequences in hepatoma and non-hepatoma cells. We found that nucleotides -233 to -116 preferentially enhanced the expression of reporter gene in mouse hepatoma cell lines in an orientation- and promoter context-independent manner. DNase I footprinting using nuclear extracts prepared from hepatoma and non-hepatoma cells identified four protein binding sites at nucleotides -205 to -186 (site A), -181 to -164 (site B), -153 to -135 (site C), and -128 to -120 (site D). Further analyses revealed that, while site B alone played a major part for the enhancer function, sites A and B combined conferred full enhancer activity. Site-directed mutagenesis results also supported these results. Gel retardation experiments using oligonucleotide competitors revealed that the site B contains a dominant binding protein. This is the first report demonstrating a cell type-specific enhancer in the mdr locus. The role of this enhancer in the activation of mdr1b gene during hepatocarcinogenesis is discussed.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Animals
- Base Sequence
- Carcinoma, Hepatocellular/genetics
- DNA Footprinting
- DNA Mutational Analysis
- DNA-Binding Proteins/metabolism
- Enhancer Elements, Genetic
- Gene Expression Regulation, Neoplastic
- Genes, Reporter
- Liver Neoplasms/genetics
- Mice
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Promoter Regions, Genetic
- Protein Binding
- Regulatory Sequences, Nucleic Acid
- Tissue Distribution
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- R Song
- Department of Molecular Pathology, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA
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18
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Gupta S. P-glycoprotein expression and regulation. Age-related changes and potential effects on drug therapy. Drugs Aging 1995; 7:19-29. [PMID: 7579778 DOI: 10.2165/00002512-199507010-00003] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
P-Glycoprotein is a member of a superfamily of adenosine triphosphate-binding cassette transporter proteins and plays an important role in multidrug resistance in cancer cells. P-Glycoprotein is known to transport a wide variety of substances ranging from ions to peptides. P-Glycoprotein is expressed on a variety of normal cells, however its physiological function is unclear. The apical and polar distribution on secretory cells suggests a secretory role for P-glycoprotein. More recently, cells of the immune system have been shown to express P-glycoprotein. There is evidence to suggest that P-glycoprotein may play a role in the secretion of certain cytokines (especially those lacking signal sequence) and cytotoxic molecules. In this article, the basic structure, gene regulation and expression of P-glycoprotein are reviewed. Furthermore, age-related changes in the expression of P-glycoprotein and potential effects on drug therapy in the elderly are discussed.
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Affiliation(s)
- S Gupta
- Division of Basic and Clinical Immunology, University of California, Irvine, USA
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19
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Silverman JA, Hill BA. Characterization of the basal and carcinogen regulatory elements of the rat mdr1b promoter. Mol Carcinog 1995; 13:50-9. [PMID: 7766310 DOI: 10.1002/mc.2940130109] [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
In this report we characterized the transcriptional regulation of the rat mdr1b gene by xenobiotics. The expression of this gene was increased in primary rat hepatocytes and in the H4-II-E hepatoma cell line by exposure to carcinogens such as aflatoxin B1, N-acetoxy-2-acetylaminofluorene, and methyl methanesulfonate. Nuclear run-on experiments indicated that the higher steady-state levels of mdr1b mRNA were due to an increase in transcription. The 5'-flanking region of the mdr1b gene was isolated, sequenced, and functionally characterized in transient and stable transfection assays. A single transcription start site was identified for this gene; no alternate start sites were used after induction with aflatoxin B1. Deletion analysis of this promoter demonstrated that the sequence between nt -214 and -178 was critical for basal promoter activity. This region did not contain any consensus-binding sites for previously identified transcription factors. A negative regulatory region was also identified between nt -940 and -250. No specific carcinogen-responsive element was identified; the xenobiotic response required a large part of the promoter. These data suggest that the carcinogen induction of mdr1b expression is mediated through sequences that overlap or that are identical to the basal promoter element.
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Affiliation(s)
- J A Silverman
- Laboratory of Experimental Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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20
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Hu XF, Slater A, Wall DM, Kantharidis P, Parkin JD, Cowman A, Zalcberg JR. Rapid up-regulation of mdr1 expression by anthracyclines in a classical multidrug-resistant cell line. Br J Cancer 1995; 71:931-6. [PMID: 7734315 PMCID: PMC2033794 DOI: 10.1038/bjc.1995.180] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Studies were carried out in a variant human multidrug-resistant (MDR) cell line CEM/A7R, which expresses very low levels of mdr1 mRNA and P-glycoprotein (P-gp). The induction of mdr1 RNA expression by three anthracyclines, (doxorubicin, daunorubicin, epirubicin), VP-16 and two vinca alkaloids (vincristine, vinblastine) was semiquantitatively assessed by scanning Northern blots on a phosphorimager. The relative level of mdr1 expression was expressed as ratio of mdr1 to the internal RNA (actin). A significant increase (P < 0.02) in expression of mdr1 was noted within 4 hrs of exposure to 1.5 micrograms ml-1 daunorubicin or epirubicin. Neither vinblastine nor vincristine had any effect on mdr1 levels after an 8 h exposure. With increasing concentrations of daunorubicin or epirubicin in a fixed 24 h time period, mdr1 expression increased, although a biphasic response was seen. Based on MRK 16 binding, an increase in P-gp levels was seen in the CEM/A7R line after a 24 h exposure to 1 microgram ml-1 daunorubicin or epirubicin. The rapid increase in mdr1 expression after a short period of exposure to doxorubicin, daunorubicin or epirubicin suggests that induction of mdr1 expression may have an important role in the development of drug-resistant tumours.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- Antibiotics, Antineoplastic/pharmacology
- Blotting, Northern
- Daunorubicin/pharmacology
- Doxorubicin/pharmacology
- Drug Resistance, Multiple/genetics
- Epirubicin/pharmacology
- Flow Cytometry
- Gene Expression Regulation, Leukemic/drug effects
- Humans
- Leukemia-Lymphoma, Adult T-Cell/drug therapy
- Leukemia-Lymphoma, Adult T-Cell/genetics
- Leukemia-Lymphoma, Adult T-Cell/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Tumor Cells, Cultured
- Up-Regulation/drug effects
- Vinblastine/pharmacology
- Vincristine/pharmacology
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Affiliation(s)
- X F Hu
- Department of Medical Oncology, Heidelberg Repatriation Hospital, Victoria, Australia
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21
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Abstract
Previously, we have shown that integrated copies of polyoma DNA can be induced to replicate in rat fibroblasts (H3 cells) exposed to a DNA-damaging agent. In the current study, we demonstrate that UV-irradiation of mouse fibroblasts (WOP cells), transiently transfected with polyoma DNA, results in repression of polyoma replication. Cotransfection of oligomers representing wild-type but not mutated forms of the PEBP2 target sequence restored levels of viral replication indicating a role of PEBP2 binding proteins in mediating this effect. DNA-binding assays revealed that a different subset of complexes was formed with the PEBP2 target sequence when nuclear proteins from sham and UV-irradiated WOP and H3 cells were compared, suggesting that the activities of PEBP2 binding proteins are differentially regulated upon UV-irradiation in these two cell types. The ability of PEBP2 to modulate polyoma replication following UV-irradiation in WOP cells suggests a potential role of PEBP2 proteins in the cellular response to DNA damage.
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Affiliation(s)
- S E Rutberg
- Molecular Carcinogenesis Program, American Health Foundation, Valhalla, NY 10595
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22
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Fardel O, Loyer P, Lecureur V, Glaise D, Guillouzo A. Constitutive expression of functional P-glycoprotein in rat hepatoma cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 219:521-8. [PMID: 7905826 DOI: 10.1111/j.1432-1033.1994.tb19967.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
P-glycoprotein is a plasma-membrane glycoprotein involved in multidrug resistance. P-glycoprotein overexpression has been demonstrated to occur in tumor cells after cytotoxic drug exposure, but also in some cancers including hepatocellular carcinomas before any chemotherapeutic treatment. In order to better analyze this constitutive type of tumoral drug resistance, we have investigated P-glycoprotein expression and function in rat liver tumors induced experimentally by administration of diethylnitrosamine and in two cell clones derived from one of these tumors designated as RHC1 and RHC2. High levels of P-glycoprotein mRNAs were found in both liver tumor samples and the two hepatoma cell clones as assessed by Northern blotting; both RHC1 and RHC2 cells displayed altered liver functions commonly observed in rat hepatoma cells, particularly the decreased expression of albumin and overexpression of the fetal glutathione S-transferase 7-7. The use of specific multidrug resistance (mdr) probes revealed a major induction of the mdr1 gene in liver tumor samples while RHC1 and RHC2 cells expressed both mdr1 and mdr3 genes without displaying a major alteration in the number of mdr gene copies as assessed by Southern blotting. High amounts of P-glycoprotein were also demonstrated in RHC1 and RHC2 cells by Western blotting. These cells were strongly resistant to doxorubicin and vinblastine, two anticancer drugs transported by P-glycoprotein. Doxorubicin intracellular retention was low in RHC1 and RHC2 cells, but was strongly enhanced in the presence of verapamil, a known modulator agent of P-glycoprotein; low retention appeared to occur via a drug efflux mechanism, indicating that P-glycoprotein was fully active. These results show that rat hepatoma cells can display elevated levels of functional P-glycoprotein without any prior cytotoxic drug selection and suggest that these cells represent a useful model for analyzing P-glycoprotein regulation in intrinsically clinical drug-resistant cancers.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Animals
- Carcinoma, Hepatocellular/chemically induced
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- Carrier Proteins/biosynthesis
- Carrier Proteins/genetics
- Clone Cells
- Cycloheximide/pharmacology
- Diethylnitrosamine/toxicity
- Doxorubicin/metabolism
- Drug Resistance
- Female
- Gene Expression
- Glutathione Transferase/biosynthesis
- Liver Neoplasms/chemically induced
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/isolation & purification
- RNA, Neoplasm/biosynthesis
- RNA, Neoplasm/isolation & purification
- Rats
- Rats, Sprague-Dawley
- Serum Albumin/biosynthesis
- Transcription, Genetic/drug effects
- Tumor Cells, Cultured
- Verapamil/pharmacology
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Affiliation(s)
- O Fardel
- Unité de Recherches Hépatologiques U 49 de l'Institut National de la Santé et de la Recherche Médicale, Hôpital Pontchaillou, Rennes, France
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23
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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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24
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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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25
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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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26
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Thorgeirsson SS, Gant TW, Silverman JA. Transcriptional regulation of multidrug resistance gene expression. Cancer Treat Res 1994; 73:57-68. [PMID: 7710910 DOI: 10.1007/978-1-4615-2632-2_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- S S Thorgeirsson
- Laboratory of Experimental Carcinogenesis, National Cancer Institute, Bethesda, MD 20892-0037
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27
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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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28
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SP1 activates the MDR1 promoter through one of two distinct G-rich regions that modulate promoter activity. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)36544-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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29
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Zastawny RL, Ling V. Structural and functional analysis of 5' flanking and intron 1 sequences of the hamster P-glycoprotein pgp1 and pgp2 genes. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1173:303-13. [PMID: 8100449 DOI: 10.1016/0167-4781(93)90128-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Several studies have demonstrated that regulation of P-glycoprotein gene expression at the transcriptional level is complex and involves multiple regulatory mechanisms. To investigate the transcriptional regulation of P-glycoprotein genes, genomic DNA fragments containing the 5' end of the hamster pgp1 and pgp2 genes were isolated and characterized. The pgp1 5' flanking sequences were linked to the chloramphenicol acetyltransferase (CAT) reporter gene and a series of 5' deletions were constructed. Transient expression of these CAT constructs into Chinese hamster ovary (CHO) cells revealed that the pgp1 promoter is regulated by multiple positive and negative regulatory elements. One particular region between -489 and -255 was shown to possess silencer activity. This region contains two putative negative elements that are also present in the silencer regions of several other genes. Intron 1 sequences of the Pgp genes were also examined and shown to be highly conserved both between family members and across species. Transient expression studies revealed that intron 1 sequences possess enhancer activity. Thus, it was demonstrated that sequences upstream and downstream of the transcriptional start site are important for the regulation of P-glycoprotein gene expression.
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Affiliation(s)
- R L Zastawny
- Ontario Cancer Institute, University of Toronto, Canada
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30
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Yu L, Cohen D, Piekarz R, Horwitz S. Three distinct nuclear protein binding sites in the promoter of the murine multidrug resistance mdr1b gene. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53206-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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31
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Goldsmith M, Madden M, Morrow C, Cowan K. A Y-box consensus sequence is required for basal expression of the human multidrug resistance (mdr1) gene. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53398-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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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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Kuo MT. Expression of multidrug-resistance (P-glycoprotein) genes in liver cancers: a molecular example of the convergence theory of hepatocarcinogenesis? Mol Carcinog 1993; 7:73-5. [PMID: 8096140 DOI: 10.1002/mc.2940070203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- M T Kuo
- Department of Molecular Pathology, University of Texas M.D. Anderson Cancer Center, Houston 77030
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Gant TW, Silverman JA, Thorgeirsson SS. Regulation of P-glycoprotein gene expression in hepatocyte cultures and liver cell lines by a trans-acting transcriptional repressor. Nucleic Acids Res 1992; 20:2841-6. [PMID: 1352042 PMCID: PMC336930 DOI: 10.1093/nar/20.11.2841] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previously we have demonstrated that expression of the multidrug resistance (mdr) genes in rat liver and primary rat hepatocyte cultures is induced by exposure to 2-acetylaminofluorene and 3-methylcholanthrene. The mdr expression induced by both of these compounds occurs primarily via increased gene transcription. To determine the nature of possible regulatory proteins involved in mdr gene regulation we inhibited protein synthesis using cycloheximide or emetine in primary rat hepatocyte cultures, mouse (HePa 1), human (Hep G2) and rat (H4-II-E) cell lines. Each cell type responded by strongly increasing its steady state mdr1 mRNA levels. In hepatocytes increased mdr expression was observed after greater than 50% inhibition of protein synthesis, and was first detected after 2h of protein synthesis inhibition with maximal induction occurring by 24h. Nuclear run-on analysis showed that the increased steady state mRNA level was due to increased gene transcription without alteration of the transcription start site. Combined these data indicate that one regulatory mechanism by which mdr gene expression is controlled is via a trans-acting transcriptional repressor.
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Affiliation(s)
- T W Gant
- Laboratory of Experimental Carcinogenesis, National Cancer Institute, Bethesda, MD 20892
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Yanagishita M. Glycosylphosphatidylinositol-anchored and core protein-intercalated heparan sulfate proteoglycans in rat ovarian granulosa cells have distinct secretory, endocytotic, and intracellular degradative pathways. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50119-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
The discovery of an energy-dependent pump system for natural product anticancer drugs has important implications for the biology of related energy-dependent transport systems as well as for the treatment of human cancer. To fully realize the therapeutic potential associated with manipulation of the multidrug transporter, it will be necessary to understand the mechanisms of action of the transporter and its mode of regulation. This review has summarized recent developments in these areas which suggest that both the activity of the pump and its genetic regulation are potential targets for new anticancer therapies.
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Affiliation(s)
- K V Chin
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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