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Shin DW, Lee JC, Kim J, Yoon YS, Han HS, Kim H, Hwang JH. Tailored adjuvant gemcitabine versus 5-fluorouracil/folinic acid based on hENT1 immunohistochemical staining in resected pancreatic ductal adenocarcinoma: A biomarker stratified prospective trial. Pancreatology 2021; 21:796-804. [PMID: 33795193 DOI: 10.1016/j.pan.2021.02.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/14/2021] [Accepted: 02/25/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND The study aimed to evaluate the clinical outcomes of tailored adjuvant chemotherapy according to human equilibrative nucleoside transporter 1 (hENT1) expression in resected pancreatic ductal adenocarcinoma (PDA). METHODS Patients who underwent pancreatectomy for PDA were enrolled prospectively. According to intra-tumoral hENT1 expression, the high hENT1 (≥50%) group received gemcitabine and the low hENT1 (<50%) group received 5-fluorouracil plus folinic acid (5-FU/FA). The propensity score-matched control consisted of patients who received hENT1-independent adjuvant chemotherapy. The primary outcome was recurrence free survival (RFS) and the secondary outcomes were overall survival (OS) and toxicities. RESULTS Between May 2015 and June 2017, we enrolled 44 patients with resected PDA. During a median follow-up period of 28.5 months, the intention-to-treat population showed much longer median RFS [22.9 (95% CI, 11.3-34.5) vs. 10.9 (95% CI, 6.9-14.9) months, P = 0.043] and median OS [36.2 (95% CI, 26.5-45.9) vs. 22.1 (95% CI, 17.7-26.6) months, P = 0.001] compared to the controls. Among 5 patients in the low hENT1 group who discontinued treatment, 2 patients receiving 5-FU/FA discontinued treatment due to drug toxicities (febrile neutropenia and toxic epidermal necrolysis). CONCLUSION Tailored adjuvant chemotherapy based on hENT1 staining provides excellent clinical outcomes among patients with resected PDA. CLINICAL TRIAL REGISTRATION clinicaltrials.gov identifier: NCT02486497.
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Affiliation(s)
- Dong Woo Shin
- Division of Gastroenterology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea; Division of Gastroenterology, Department of Internal Medicine, Keimyung University School of Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Jong-Chan Lee
- Division of Gastroenterology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Jaihwan Kim
- Division of Gastroenterology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Yoo-Seok Yoon
- Department of Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Ho-Seong Han
- Department of Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Haeryoung Kim
- Department of Pathology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jin-Hyeok Hwang
- Division of Gastroenterology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
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Abstract
Nucleosides play central roles in all facets of life, from metabolism to cellular signaling. Because of their physiochemical properties, nucleosides are lipid bilayer impermeable and thus rely on dedicated transport systems to cross biological membranes. In humans, two unrelated protein families mediate nucleoside membrane transport: the concentrative and equilibrative nucleoside transporter families. The objective of this review is to provide a broad outlook on the current status of nucleoside transport research. We will discuss the role played by nucleoside transporters in human health and disease, with emphasis placed on recent structural advancements that have revealed detailed molecular principles of these important cellular transport systems and exploitable pharmacological features.
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Affiliation(s)
- Nicholas J. Wright
- Department of Biochemistry, Duke University Medical Center, 303 Research Drive, Durham, North Carolina, 27710, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University Medical Center, 303 Research Drive, Durham, North Carolina, 27710, USA
- Correspondence and requests for materials should be addressed to: S.-Y. Lee., , tel: 919-684-1005, fax: 919-684-8885
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3
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Bird NTE, Elmasry M, Jones R, Psarelli E, Dodd J, Malik H, Greenhalf W, Kitteringham N, Ghaneh P, Neoptolemos JP, Palmer D. Immunohistochemical hENT1 expression as a prognostic biomarker in patients with resected pancreatic ductal adenocarcinoma undergoing adjuvant gemcitabine-based chemotherapy. Br J Surg 2017; 104:328-336. [PMID: 28199010 DOI: 10.1002/bjs.10482] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/12/2016] [Accepted: 12/08/2016] [Indexed: 12/28/2022]
Abstract
BACKGROUND Human equilibrative nucleoside transporters (hENTs) are transmembranous proteins that facilitate the uptake of nucleosides and nucleoside analogues, such as gemcitabine, into the cell. The abundance of hENT1 transporters in resected pancreatic ductal adenocarcinoma (PDAC) might make hENT1 a potential biomarker of response to adjuvant chemotherapy. The aim of this study was to see whether hENT1 expression, as determined by immunohistochemistry, was a suitable predictive marker for subsequent treatment with gemcitabine-based adjuvant chemotherapy. METHODS A systematic review was performed, searching databases from January 1997 to January 2016. Articles pertaining to hENT1 immunohistochemical analysis in resected PDAC specimens from patients who subsequently underwent adjuvant gemcitabine-based chemotherapy were identified. Eligible studies were required to contain survival data, reporting specifically overall survival (OS) and disease-free survival (DFS) with associated hazard ratios (HRs) stratified by hENT1 status. RESULTS Of 42 articles reviewed, eight were suitable for review, with seven selected for quantitative meta-analysis. The total number of patients included in the meta-analysis was 770 (405 hENT1-negative, 365 hENT1-positive). Immunohistochemically detected hENT1 expression was significantly associated with both prolonged DFS (HR 0·58, 95 per cent c.i. 0·42 to 0·79) and OS (HR 0·52, 0·38 to 0·72) in patients receiving adjuvant gemcitabine but not those having fluoropyrimidine-based adjuvant therapy. CONCLUSION Expression of hENT1 is a suitable prognostic biomarker in patients undergoing adjuvant gemcitabine-based chemotherapy.
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Affiliation(s)
- N T E Bird
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - M Elmasry
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - R Jones
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - E Psarelli
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - J Dodd
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - H Malik
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - W Greenhalf
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - N Kitteringham
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - P Ghaneh
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - J P Neoptolemos
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
| | - D Palmer
- Liverpool University Pharmacology Unit, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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4
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Dos Santos-Rodrigues A, Pereira MR, Brito R, de Oliveira NA, Paes-de-Carvalho R. Adenosine transporters and receptors: key elements for retinal function and neuroprotection. VITAMINS AND HORMONES 2015; 98:487-523. [PMID: 25817878 DOI: 10.1016/bs.vh.2014.12.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Adenosine is an important neuroactive substance in the central nervous system, including in the retina where subclasses of adenosine receptors and transporters are expressed since early stages of development. Here, we review some evidence showing that adenosine plays important functions in the mature as well as in the developing tissue. Adenosine transporters are divided into equilibrative and concentrative, and the major transporter subtype present in the retina is the ENT1. This transporter is responsible for a bidirectional transport of adenosine and the uptake or release of this nucleoside appears to be regulated by different signaling pathways that are also controlled by activation of adenosine receptors. Adenosine receptors are also key players in retina physiology regulating a variety of functions in the mature and developing tissue. Regulation of excitatory neurotransmitter release and neuroprotection are the main functions played be adenosine in the mature tissue, while regulation of cell survival and neurogenesis are some of the functions played by adenosine in developing retina. Since adenosine is neuroprotective against excitotoxic and metabolic dysfunctions observed in neurological and ocular diseases, the search for adenosine-related drugs regulating adenosine transporters and receptors can be important for advancement of therapeutic strategies against these diseases.
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Affiliation(s)
| | - Mariana R Pereira
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Rafael Brito
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Nádia A de Oliveira
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
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5
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Dos Santos-Rodrigues A, Grañé-Boladeras N, Bicket A, Coe IR. Nucleoside transporters in the purinome. Neurochem Int 2014; 73:229-37. [PMID: 24704797 DOI: 10.1016/j.neuint.2014.03.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 03/23/2014] [Accepted: 03/24/2014] [Indexed: 01/20/2023]
Abstract
The purinome is a rich complex of proteins and cofactors that are involved in fundamental aspects of cellular homeostasis and cellular responses. The purinome is evolutionarily ancient and is made up of thousands of members. Our understanding of the mechanisms linking some parts of this complex network and the physiological relevance of the various connections is well advanced. However, our understanding of other parts of the purinome is less well developed. Our research focuses on the adenosine or nucleoside transporters (NTs), which are members of the membrane purinome. Nucleoside transporters are integral membrane proteins that are responsible for the flux of nucleosides, such as adenosine, and nucleoside analog drugs, used in a variety of anti-cancer, anti-viral and anti-parasite therapies, across cell membranes. Nucleoside transporters form the SLC28 and SLC29 families of solute carriers and the protein members of these families are widely distributed in human tissues including the central nervous system (CNS). NTs modulate purinergic signaling in the CNS primarily through their effects on modulating prevailing adenosine levels inside and outside the cell. By clearing the extracellular milieu of adenosine, NTs can terminate adenosine receptor-dependent signaling and this raises the possibility of regulatory feedback loops that tie together receptor signaling with transporter function. Despite the important role of NTs as modulators of purinergic signaling in the human body, very little is known about the nature or underlying mechanisms of regulation of either the SLC28 or SLC29 families, particularly within the context of the CNS purinome. Here we provide a brief overview of our current understanding of the regulation of members of the SLC29 family and highlight some interesting avenues for future research.
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Affiliation(s)
| | - Natalia Grañé-Boladeras
- Department of Chemistry and Biology, Faculty of Science, Ryerson University, Toronto, ON, Canada
| | - Alex Bicket
- Department of Biology, Faculty of Science, York University, Toronto, ON, Canada
| | - Imogen R Coe
- Department of Biology, Faculty of Science, York University, Toronto, ON, Canada; Department of Chemistry and Biology, Faculty of Science, Ryerson University, Toronto, ON, Canada.
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6
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Furihata T, Mizuguchi M, Suzuki Y, Matsumoto S, Kobayashi K, Chiba K. Identification of primary equilibrative nucleoside transporter 1 mRNA isoforms resulting from alternative promoter usage in human hepatocytes. Drug Metab Pharmacokinet 2014; 29:325-32. [PMID: 24522200 DOI: 10.2133/dmpk.dmpk-13-rg-135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human equilibrative nucleoside transporter 1 (hENT1) transports various nucleoside analogues into cells. Although the single hENT1 promoter region (P1) and the mRNA isoform (a1) have been characterized previously, we have recently identified additional promoter regions P2 and P3 (which primarily generate c1/2/3 mRNAs and d1/2/3/4 mRNAs, respectively) in the human liver. Therefore, this study aimed at identifying the primary hENT1 mRNA isoforms expressed in human hepatocytes, while simultaneously obtaining functional evidence of alternative hENT1 promoter usage. Our results showed that the expressions of hENT1c1, d3, and (to a lesser extent) c2 mRNAs were strikingly predominant over the other mRNA isoforms in human hepatocytes, that the abundant expression of these mRNAs was consistent with the high levels of P2 and P3 promoter activity, and that these promoters were significantly marked by transcriptionally active histone modification in hepatic cells. To summarize, our results demonstrate that, resulting from the manipulated alternative promoter usage, hENT1c1 and d3 (and c2) mRNAs are primarily expressed in human hepatocytes, which suggests that they may play important roles in controlling hENT1 expression levels in those cells. Our findings are expected to provide significant insights into the molecular machinery of hENT1 expression control.
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Affiliation(s)
- Tomomi Furihata
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University
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7
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Young JD, Yao SYM, Baldwin JM, Cass CE, Baldwin SA. The human concentrative and equilibrative nucleoside transporter families, SLC28 and SLC29. Mol Aspects Med 2013; 34:529-47. [PMID: 23506887 DOI: 10.1016/j.mam.2012.05.007] [Citation(s) in RCA: 243] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/11/2012] [Indexed: 12/23/2022]
Abstract
Nucleoside transport in humans is mediated by members of two unrelated protein families, the SLC28 family of cation-linked concentrative nucleoside transporters (CNTs) and the SLC29 family of energy-independent, equilibrative nucleoside transporters (ENTs). These families contain three and four members, respectively, which differ both in the stoichiometry of cation coupling and in permeant selectivity. Together, they play key roles in nucleoside and nucleobase uptake for salvage pathways of nucleotide synthesis. Moreover, they facilitate cellular uptake of several nucleoside and nucleobase drugs used in cancer chemotherapy and treatment of viral infections. Thus, the transporter content of target cells can represent a key determinant of the response to treatment. In addition, by regulating the concentration of adenosine available to cell surface receptors, nucleoside transporters modulate many physiological processes ranging from neurotransmission to cardiovascular activity. This review describes the molecular and functional properties of the two transporter families, with a particular focus on their physiological roles in humans and relevance to disease treatment.
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Affiliation(s)
- James D Young
- Membrane Protein Research Group, Edmonton, Alberta, Canada T6G 2H7.
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8
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Candelaria M, de la Cruz-Hernandez E, Taja-Chayeb L, Perez-Cardenas E, Trejo-Becerril C, Gonzalez-Fierro A, Chavez-Blanco A, Soto-Reyes E, Dominguez G, Trujillo JE, Diaz-Chavez J, Duenas-Gonzalez A. DNA methylation-independent reversion of gemcitabine resistance by hydralazine in cervical cancer cells. PLoS One 2012; 7:e29181. [PMID: 22427797 PMCID: PMC3299634 DOI: 10.1371/journal.pone.0029181] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 11/22/2011] [Indexed: 11/18/2022] Open
Abstract
Background Down regulation of genes coding for nucleoside transporters and drug metabolism responsible for uptake and metabolic activation of the nucleoside gemcitabine is related with acquired tumor resistance against this agent. Hydralazine has been shown to reverse doxorubicin resistance in a model of breast cancer. Here we wanted to investigate whether epigenetic mechanisms are responsible for acquiring resistance to gemcitabine and if hydralazine could restore gemcitabine sensitivity in cervical cancer cells. Methodology/Principal Findings The cervical cancer cell line CaLo cell line was cultured in the presence of increasing concentrations of gemcitabine. Down-regulation of hENT1 & dCK genes was observed in the resistant cells (CaLoGR) which was not associated with promoter methylation. Treatment with hydralazine reversed gemcitabine resistance and led to hENT1 and dCK gene reactivation in a DNA promoter methylation-independent manner. No changes in HDAC total activity nor in H3 and H4 acetylation at these promoters were observed. ChIP analysis showed H3K9m2 at hENT1 and dCK gene promoters which correlated with hyper-expression of G9A histone methyltransferase at RNA and protein level in the resistant cells. Hydralazine inhibited G9A methyltransferase activity in vitro and depletion of the G9A gene by iRNA restored gemcitabine sensitivity. Conclusions/Significance Our results demonstrate that acquired gemcitabine resistance is associated with DNA promoter methylation-independent hENT1 and dCK gene down-regulation and hyper-expression of G9A methyltransferase. Hydralazine reverts gemcitabine resistance in cervical cancer cells via inhibition of G9A histone methyltransferase.
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Affiliation(s)
- Myrna Candelaria
- Division of Clinical Research, Instituto Nacional de Cancerologia, Mexico City, Mexico
| | | | - Lucia Taja-Chayeb
- Division of Basic Research, Instituto Nacional de Cancerologia, Mexico City, Mexico
| | | | | | | | - Alma Chavez-Blanco
- Division of Basic Research, Instituto Nacional de Cancerologia, Mexico City, Mexico
| | - Ernesto Soto-Reyes
- Division of Basic Research, Instituto Nacional de Cancerologia, Mexico City, Mexico
| | - Guadalupe Dominguez
- Division of Basic Research, Instituto Nacional de Cancerologia, Mexico City, Mexico
| | - Jaenai E. Trujillo
- Division of Basic Research, Instituto Nacional de Cancerologia, Mexico City, Mexico
| | - Jose Diaz-Chavez
- Division of Basic Research, Instituto Nacional de Cancerologia, Mexico City, Mexico
| | - Alfonso Duenas-Gonzalez
- Unit of Biomedical Research in Cancer. Instituto Nacional de Cancerologia/Instituto de Investigaciones Biomedicas UNAM, Mexico City, Mexico
- * E-mail:
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9
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Baer-Dubowska W, Majchrzak-Celińska A, Cichocki M. Pharmocoepigenetics: a new approach to predicting individual drug responses and targeting new drugs. Pharmacol Rep 2011; 63:293-304. [DOI: 10.1016/s1734-1140(11)70498-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/19/2010] [Indexed: 12/14/2022]
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10
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Marvi M, Rose JB, Bang A, Moon BC, Pozeg Z, Ibrahim M, Peniston C, Coe IR. Nucleoside transporter expression profiles in human cardiac tissue show striking individual variability with overall predominance of hENT1. Eur J Pharm Sci 2010; 41:685-91. [PMID: 20883780 DOI: 10.1016/j.ejps.2010.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 09/17/2010] [Accepted: 09/21/2010] [Indexed: 11/25/2022]
Abstract
Nucleoside transporters (NTs) are integral membrane transport proteins that modulate the flux of nucleosides such as adenosine across cell membranes. Two families of NTs exist, the concentrative NTs (CNTs, SLC28) and the equilibrative NTs (ENTs, SLC29). CNTs and ENTs transport anti-cancer and anti-viral nucleoside analog drugs and ENTs are also targets of drugs used to treat cardiac pathologies. Levels of some NT profiles have been shown to relate to clinical outcomes in the use of nucleoside analog drugs. However, currently, patient NT profile is not assessed prior to pharmacological administration of analog drugs. Here we describe a reliable method to determine a complete individual NT expression profile from human tissue using quantitative real-time PCR. We developed this assay on tissue (right atrial appendage, left internal mammary, aorta) from individuals undergoing cardiac surgery and compared these findings to the NT expression profiles in pooled whole heart tissue (normal and diseased). Data show that hENT1 is the most abundantly expressed NT, with highest expression levels in the aorta. However, NT expression profiles are highly variable among individuals and changes in NT expression between normal and diseased tissues were observed. These data are the first to describe the RNA expression patterns of all seven NT isoforms in the human heart. The methodology described here may be useful for quantitatively characterizing complete NT expression profiles in any human target tissue.
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Affiliation(s)
- Melissa Marvi
- Department of Biology, Muscle Health Research Centre, York University, Toronto, ON, Canada
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11
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Fukuchi Y, Furihata T, Hashizume M, Iikura M, Chiba K. Characterization of ribavirin uptake systems in human hepatocytes. J Hepatol 2010; 52:486-92. [PMID: 20185188 DOI: 10.1016/j.jhep.2010.01.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 08/31/2009] [Accepted: 09/16/2009] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS The purpose of this study was to identify the major ribavirin uptake transporter(s) in human hepatocytes and to determine if these previously unidentified transporters are involved in hepatic ribavirin uptake. Furthermore, we aimed to address what causes the difference in uptake levels among human hepatocytes. METHODS Profiles of ribavirin uptake and nucleoside transporter mRNA expression in Caucasian hepatocytes (HH268, HH283 and HH291) were characterized by transport assay and reverse transcription-polymerase chain reaction (RT-PCR). The 5'-side of the SLC29A1 gene structure was characterized by determination of transcription start sites and by RT-PCR. RESULTS Equilibrative nucleoside transporter 1 (ENT1)-mediated uptake was exclusively involved in ribavirin uptake in HH268 and HH283 and was responsible for the largest ribavirin uptake fraction in HH291. The level of ENT1-mediated uptake in HH291 was higher than that in HH268 and HH283. Characterization of the SLC29A1 gene structure revealed the existence of several ENT1 mRNA isoforms in the human liver, and the levels of four ENT1 mRNA isoforms in HH291 were higher than those in HH268 or HH283. No ENT2-mediated uptake was observed in any hepatocyte lines. Na(+)-dependent uptake was detected only in HH291; however, mRNA levels of concentrative nucleoside transporters (CNTs) were at trace levels in all hepatocyte lines. CONCLUSIONS ENT1, but not ENT2 or CNTs, is a major ribavirin uptake transporter in human hepatocytes. The different ENT1-mediated ribavirin uptake levels in different hepatocyte lines are associated with different expression levels of specific isoforms of ENT1 mRNAs. Furthermore, an unidentified Na(+)-dependent ribavirin transport system might exist in human hepatocytes.
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Affiliation(s)
- Yukina Fukuchi
- Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba-shi, Chiba, Japan
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12
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Farías M, Puebla C, Westermeier F, Jo MJ, Pastor-Anglada M, Casanello P, Sobrevia L. Nitric oxide reduces SLC29A1 promoter activity and adenosine transport involving transcription factor complex hCHOP–C/EBPα in human umbilical vein endothelial cells from gestational diabetes. Cardiovasc Res 2009; 86:45-54. [DOI: 10.1093/cvr/cvp410] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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13
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Candelaria M, de la Cruz-Hernández E, Pérez-Cárdenas E, Trejo-Becerril C, Gutiérrez-Hernández O, Dueñas-González A. Pharmacogenetics and pharmacoepigenetics of gemcitabine. Med Oncol 2009; 27:1133-43. [PMID: 19902390 DOI: 10.1007/s12032-009-9349-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 10/21/2009] [Indexed: 12/19/2022]
Abstract
Gemcitabine (2',2'-difluoro 2'deoxycytidine, dFdC) is an analog of cytosine with distinctive pharmacological properties and a wide antitumor-activity spectrum. The pharmacological characteristics of gemcitabine are unique because two main classes of genes are essential for its antitumor effects: membrane transporter protein-coding genes, whose products are responsible for drug intracellular uptake, as well as enzyme-coding genes, which catalyze its activation and inactivation. The study of the pharmacogenetics and pharmacoepigenetics of these two gene classes is greatly required to optimize the drug's therapeutic use in cancer. This review aims to provide an update of genetic and epigenetic bases that may account for interindividual variation in therapeutic outcome exhibited by gemcitabine.
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Affiliation(s)
- M Candelaria
- Division of Clinical Research, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
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14
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Li L, Koo SH, Hong IHK, Lee EJD. Identification of functional promoter haplotypes of human concentrative nucleoside transporter 2, hCNT2 (SLC28A2). Drug Metab Pharmacokinet 2009; 24:161-6. [PMID: 19430172 DOI: 10.2133/dmpk.24.161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human concentrative nucleoside transporter 2 (hCNT2) plays a major role in the intestinal absorption of naturally occurring nucleosides as well as some nucleoside analog drugs. To determine if single nucleotide polymorphisms (SNPs) in the promoter region of hCNT2 affect gene expression, we examined approximately 1 kb upstream the hCNT2 transcription start site. Ninety Chinese samples were screened and seven SNPs were identified: -115T>G, -146T>A, -264A>G, -564G>A, -861A>C, -880T>C and -906C>T. Based on these seven variants and their relative positions, eight haplotypes were identified using PHASE v2.1.1. Three naturally occurring haplotypes were cloned into the pGL3-Basic vector and transfected into HEK293 cells. Dual luciferase assay revealed that haplotype 4 (GTAGACC) and 7 (GAGAACT) exhibited significantly lower expression levels compared to the published haplotype 1 (TTAGATC). Results from our in-vitro study showed that the hCNT2 promoter region haplotype may modulate gene expression and cause different drug responses.
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Affiliation(s)
- Linghui Li
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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15
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Maréchal R, Mackey JR, Lai R, Demetter P, Peeters M, Polus M, Cass CE, Young J, Salmon I, Devière J, Van Laethem JL. Human Equilibrative Nucleoside Transporter 1 and Human Concentrative Nucleoside Transporter 3 Predict Survival after Adjuvant Gemcitabine Therapy in Resected Pancreatic Adenocarcinoma. Clin Cancer Res 2009; 15:2913-9. [DOI: 10.1158/1078-0432.ccr-08-2080] [Citation(s) in RCA: 175] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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16
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Young JD, Yao SYM, Sun L, Cass CE, Baldwin SA. Human equilibrative nucleoside transporter (ENT) family of nucleoside and nucleobase transporter proteins. Xenobiotica 2008; 38:995-1021. [PMID: 18668437 DOI: 10.1080/00498250801927427] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
1. The human (h) SLC29 family of integral membrane proteins is represented by four members, designated equilibrative nucleoside transporters (ENTs) because of the properties of the first-characterized family member, hENT1. They belong to the widely distributed eukaryotic ENT family of equilibrative and concentrative nucleoside/nucleobase transporter proteins. 2. A predicted topology of eleven transmembrane helices has been experimentally confirmed for hENT1. The best-characterized members of the family, hENT1 and hENT2, possess similar broad permeant selectivities for purine and pyrimidine nucleosides, but hENT2 also efficiently transports nucleobases. hENT3 has a similar broad permeant selectivity for nucleosides and nucleobases and appears to function in intracellular membranes, including lysosomes. 3. hENT4 is uniquely selective for adenosine, and also transports a variety of organic cations. hENT3 and hENT4 are pH sensitive, and optimally active under acidic conditions. ENTs, including those in parasitic protozoa, function in nucleoside and nucleobase uptake for salvage pathways of nucleotide synthesis and, in humans, are also responsible for the cellular uptake of nucleoside analogues used in the treatment of cancers and viral diseases. 4. By regulating the concentration of adenosine available to cell surface receptors, mammalian ENTs additionally influence physiological processes ranging from cardiovascular activity to neurotransmission.
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Affiliation(s)
- J D Young
- Membrane Protein Research Group, Department of Physiology and Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.
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