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Lee CM, Zane NR, Veal G, Thakker DR. Physiologically Based Pharmacokinetic Models for Adults and Children Reveal a Role of Intracellular Tubulin Binding in Vincristine Disposition. CPT Pharmacometrics Syst Pharmacol 2019; 8:759-768. [PMID: 31420944 PMCID: PMC6813170 DOI: 10.1002/psp4.12453] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/11/2019] [Indexed: 11/30/2022] Open
Abstract
Vincristine is a cytotoxic chemotherapeutic agent used as first-line therapy for pediatric acute lymphocytic leukemia. It is cleared by hepatic oxidative metabolism by CYP3A4 and CYP3A5 and via hepatic (biliary) efflux mediated by P-glycoprotein (P-gp) transporter. Bottom-up physiologically based pharmacokinetic (PBPK) models were developed to predict vincristine disposition in pediatric and adult populations. The models incorporated physicochemical properties, metabolism by CYP3A4/5, efflux by P-gp, and intracellular binding to β-tubulin. The adult and pediatric PBPK models predicted pharmacokinetics (PK) within twofold of the observed PK parameters (area under the curve, terminal half-life, volume of distribution, and clearance). Simulating a higher hypothetical (4.9-fold) pediatric expression of β-tubulin relative to adult improved predictions of vincristine PKs. To our knowledge, this is the first time that intracellular binding has been incorporated into a pediatric PBPK model. Utilizing this PBPK modeling approach, safe and effective doses of vincristine could be predicted.
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Affiliation(s)
- Christine M. Lee
- Division of Pharmacotherapy and Experimental TherapeuticsUNC Eshelman School of PharmacyThe University of North Carolina at Chapel HillChapel HillNorth CarolinaUSA
| | - Nicole R. Zane
- The Center for Clinical Pharmacology at The Children's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
| | - Gareth Veal
- Northern Institute for Cancer ResearchNewcastle UniversityNewcastle upon TyneUK
| | - Dhiren R. Thakker
- Division of Pharmacotherapy and Experimental TherapeuticsUNC Eshelman School of PharmacyThe University of North Carolina at Chapel HillChapel HillNorth CarolinaUSA
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Yasuda K, Ganguly S, Schuetz EG. Pheophorbide A: Fluorescent Bcrp Substrate to Measure Oral Drug-Drug Interactions in Real-Time In Vivo. Drug Metab Dispos 2018; 46:1725-1733. [PMID: 30111622 DOI: 10.1124/dmd.118.083584] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 08/13/2018] [Indexed: 01/19/2023] Open
Abstract
We investigated whether pheophorbide A (PhA) could serve as a selective breast cancer resistance protein (BCRP) substrate (victim) to screen in vivo using fluorescent live animal imaging for transporter-mediated interactions with orally administered inhibitors (perpetrators), and whether that could be coupled with serum sampling to measure the systemic concentration of PhA with a fast-throughput in vitro fluorescent assay. PhA is a breakdown product of chlorophyll and is highly fluorescent in the near-infrared (NIR) spectrum. Whole-body NIR fluorescence was greater in the Bcrp KO compared with wild-type (WT) mice fed a regular diet containing chlorophyll and PhA, with fluorescence in WT mice confined to the intestine. PhA intestinal enterocyte fluorescence, after removing lumen contents, was greater in Bcrp knockout (KO) mice versus WT mice due to PhA enterocyte absorption and lack of PhA efflux by Bcrp. This difference was eliminated by maintaining the mice on an alfalfa (chlorophyll/PhA)-free diet. The area under the fluorescence ratio-time curve up to 6 hours (AUCFL 0-6 h) of orally administrated PhA was 3.5 times greater in the Bcrp KO mice compared with WT mice, and the PhA serum concentration was 50-fold higher in KO mice. Pretreatment with known BCRP inhibitors lapatinib, curcumin, elacridar, pantoprazole, and sorafenib, at clinically relevant doses, significantly increased PhA AUCFL 0-6 h by 2.4-, 2.3-, 2.2-, 1.5-, and 1.4-fold, respectively, whereas the area under PhA serum concentration-time curve calculated up to 6 hours (AUCSerum 0-6 h) increased by 13.8-, 7.8-, 5.2-, 2.02-, and 1.45-fold, respectively, and corresponded to their hierarchy as in vitro BCRP inhibitors. Our results demonstrate that live animal imaging using PhA can be used to identify BCRP inhibitors and to assess the potential for BCRP-mediated clinical drug-drug interactions.
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Affiliation(s)
- Kazuto Yasuda
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (K.Y., S.G., E.G.S.); and Cancer and Developmental Biology Track, University of Tennessee Health Science Center, Memphis, Tennessee (S.G.)
| | - Samit Ganguly
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (K.Y., S.G., E.G.S.); and Cancer and Developmental Biology Track, University of Tennessee Health Science Center, Memphis, Tennessee (S.G.)
| | - Erin G Schuetz
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (K.Y., S.G., E.G.S.); and Cancer and Developmental Biology Track, University of Tennessee Health Science Center, Memphis, Tennessee (S.G.)
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3
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Aikawa H, Hayashi M, Ryu S, Yamashita M, Ohtsuka N, Nishidate M, Fujiwara Y, Hamada A. Visualizing spatial distribution of alectinib in murine brain using quantitative mass spectrometry imaging. Sci Rep 2016; 6:23749. [PMID: 27026287 PMCID: PMC4812395 DOI: 10.1038/srep23749] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 03/14/2016] [Indexed: 01/08/2023] Open
Abstract
In the development of anticancer drugs, drug concentration measurements in the target tissue have been thought to be crucial for predicting drug efficacy and safety. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is commonly used for determination of average drug concentrations; however, complete loss of spatial information in the target tissue occurs. Mass spectrometry imaging (MSI) has been recently applied as an innovative tool for detection of molecular distribution of pharmacological agents in heterogeneous targets. This study examined the intra-brain transitivity of alectinib, a novel anaplastic lymphoma kinase inhibitor, using a combination of matrix-assisted laser desorption ionization–MSI and LC-MS/MS techniques. We first analyzed the pharmacokinetic profiles in FVB mice and then examined the effect of the multidrug resistance protein-1 (MDR1) using Mdr1a/b knockout mice including quantitative distribution of alectinib in the brain. While no differences were observed between the mice for the plasma alectinib concentrations, diffuse alectinib distributions were found in the brain of the Mdr1a/b knockout versus FVB mice. These results indicate the potential for using quantitative MSI for clarifying drug distribution in the brain on a microscopic level, in addition to suggesting a possible use in designing studies for anticancer drug development and translational research.
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Affiliation(s)
- Hiroaki Aikawa
- Division of Clinical Pharmacology and Translational Research, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Mitsuhiro Hayashi
- Division of Clinical Pharmacology and Translational Research, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.,Department of Molecular Imaging and Pharmacokinetics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Shoraku Ryu
- Department of Molecular Imaging and Pharmacokinetics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Makiko Yamashita
- Department of Molecular Imaging and Pharmacokinetics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Naoto Ohtsuka
- Shimadzu Techno-Research Inc., 3-19-2, Minamirokugo, Ohta-ku, Tokyo 144-0045, Japan
| | - Masanobu Nishidate
- Department of Molecular Imaging and Pharmacokinetics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.,Translational Clinical Research Science &Strategy Dept., Chugai Pharmaceutical Co., Ltd., 200 Kajiwara, Kamakura, Kanagawa 247-8530, Japan.,Department of Medical Oncology and Translational Research, Graduate school of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Yasuhiro Fujiwara
- Strategic Planning Bureau, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Akinobu Hamada
- Division of Clinical Pharmacology and Translational Research, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.,Department of Molecular Imaging and Pharmacokinetics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.,Department of Medical Oncology and Translational Research, Graduate school of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
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Pharmacokinetic effects of curcumin on docetaxel mediated by OATP1B1, OATP1B3 and CYP450s. Drug Metab Pharmacokinet 2016; 31:269-75. [PMID: 27452633 DOI: 10.1016/j.dmpk.2016.02.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/23/2016] [Accepted: 02/13/2016] [Indexed: 11/20/2022]
Abstract
Curcumin can synergistically enhance docetaxel's in vitro and in vivo antitumor activity and has been co-administrated with docetaxel in clinical trials. The aim of our study is to investigate the effect of curcumin on the pharmacokinetics of docetaxel and explore its mechanism on OATP1B1, OATP1B3 and human liver microsomes (HLMs). In rats, curcumin increased the docetaxel area under the plasma concentration-time curve (AUC0-8h) and the terminal half-life (t1/2) to 1.86- and 1.55-fold, respectively. Moreover, curcumin decreased the clearance (CL) of docetaxel to 52.1%. Human embryonic kidney 293 (HEK293) cells stably expressing OATP1B1 and OATP1B3 were used to observe the effects of curcumin on OATP1B1 and OATP1B3-mediated uptake of docetaxel. Curcumin exhibited potent inhibition on OATP1B1 and OATP1B3-mediated docetaxel uptake with IC50 values of 3.81 ± 1.19 μM and 33.70 ± 1.22 μM, respectively. The inhibition of curcumin on docetaxel metabolism in HLMs indicated that curcumin can modestly inhibit the metabolism of docetaxel with the IC50 value of 22.70 ± 1.13 μM and Ki value of 24.72 ± 4.24 μM. The preclinical and clinical improved docetaxel's therapeutic efficacy when co-administrated with curcumin may be due to the inhibition of curcumin on OATP1B1, OATP1B3 and HLMs activities. Close attention should be paid when combined treatment with docetaxel and curcumin carried out clinically.
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Poulin P, Burczynski FJ, Haddad S. The Role of Extracellular Binding Proteins in the Cellular Uptake of Drugs: Impact on Quantitative In Vitro-to-In Vivo Extrapolations of Toxicity and Efficacy in Physiologically Based Pharmacokinetic-Pharmacodynamic Research. J Pharm Sci 2016; 105:497-508. [PMID: 26173749 DOI: 10.1002/jps.24571] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 06/18/2015] [Accepted: 06/18/2015] [Indexed: 01/10/2023]
Abstract
A critical component in the development of physiologically based pharmacokinetic-pharmacodynamic (PBPK/PD) models for estimating target organ dosimetry in pharmacology and toxicology studies is the understanding of the uptake kinetics and accumulation of drugs and chemicals at the cellular level. Therefore, predicting free drug concentrations in intracellular fluid will contribute to our understanding of concentrations at the site of action in cells in PBPK/PD research. Some investigators believe that uptake of drugs in cells is solely driven by the unbound fraction; conversely, others argue that the protein-bound fraction contributes a significant portion of the total amount delivered to cells. Accordingly, the current literature suggests the existence of a so-called albumin-mediated uptake mechanism(s) for the protein-bound fraction (i.e., extracellular protein-facilitated uptake mechanisms) at least in hepatocytes and cardiac myocytes; however, such mechanism(s) and cells from other organs deserve further exploration. Therefore, the main objective of this present study was to discuss further the implication of potential protein-facilitated uptake mechanism(s) on drug distribution in cells under in vivo conditions. The interplay between the protein-facilitated uptake mechanism(s) and the effects of a pH gradient, metabolism, transport, and permeation limitation potentially occurring in cells was also discussed, as this should violate the basic assumption on similar free drug concentration in cells and plasma. This was made because the published equations used to calculate drug concentrations in cells in a PBPK/PD model did not consider potential protein-facilitated uptake mechanism(s). Consequently, we corrected some published equations for calculating the free drug concentrations in cells compared with plasma in PBPK/PD modeling studies, and we proposed a refined strategy for potentially performing more accurate quantitative in vitro-to-in vivo extrapolations (IVIVEs) of toxicity (efficacy) at the cellular level from data generated in cell assays. Overall, this present study may help to optimize the human dose prediction in preclinical and clinical studies, while prescribing drugs with narrow therapeutic windows that are highly bound to extracellular proteins and/or highly ionized at the physiological pH. This may facilitate building a more accurate safety (efficacy) profile for such drugs.
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Affiliation(s)
- Patrick Poulin
- Consultant, Québec city, Québec, Canada; Department of Occupational and Environmental Health, School of Public Health, IRSPUM, Université de Montréal, Québec, Canada.
| | - Frank J Burczynski
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, University of Manitoba, Manitoba, Canada
| | - Sami Haddad
- Department of Occupational and Environmental Health, School of Public Health, IRSPUM, Université de Montréal, Québec, Canada
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Poulin P. A paradigm shift in pharmacokinetic-pharmacodynamic (PKPD) modeling: rule of thumb for estimating free drug level in tissue compared with plasma to guide drug design. J Pharm Sci 2015; 104:2359-68. [PMID: 25943586 DOI: 10.1002/jps.24468] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/07/2015] [Accepted: 04/07/2015] [Indexed: 01/04/2023]
Abstract
A basic assumption in pharmacokinetics-pharmacodynamics research is that the free drug concentration is similar in plasma and tissue, and, hence, in vitro plasma data can be used to estimate the in vivo condition in tissue. However, in a companion manuscript, it has been demonstrated that this assumption is violated for the ionized drugs. Nonetheless, these observations focus on in vitro static environments and do not challenge data with an in vivo dynamic system. Therefore, an extension from an in vitro to an in vivo system becomes the necessary next step. The objective of this study was to perform theoretical simulations of the free drug concentration in tissue and plasma by using a physiologically based pharmacokinetics (PBPK) model reproducing the in vivo conditions in human. Therefore, the effects of drug ionization, lipophilicity, and clearance have been taken into account in a dynamic system. This modeling exercise was performed as a proof of concept to demonstrate that free drug concentration in tissue and plasma may also differ in a dynamic system for passively permeable drugs that are ionized at the physiological pH. The PBPK model simulations indicated that free drug concentrations in tissue cells and plasma significantly differ for the ionized drugs because of the pH gradient effect between cells and interstitial space. Hence, a rule of thumb for potentially performing more accurate PBPK/PD modeling is suggested, which states that the free drug concentration in tissue and plasma will differ for the ionizable drugs in contrast to the neutral drugs. In addition to the pH gradient effect for the ionizable drugs, lipophilicity and clearance effects will increase or decrease the free drug concentration in tissue and plasma for each class of drugs; thus, higher will be the drug lipophilicity and clearance, lower would be the free drug concentration in plasma, and, hence, in tissue, in a dynamic in vivo system. Therefore, only considering the value of free fraction in plasma derived from a static in vitro environment might be biased to guide drug design (the old paradigm), and, hence, it is recommended to use a PBPK model to reproduce more accurately the in vivo condition in tissue (the new paradigm). This newly developed approach can be used to predict free drug concentration in diverse tissue compartments for small molecules in toxicology and pharmacology studies, which can be leveraged to optimize the pharmacokinetics drivers of tissue distribution based upon physicochemical and physiological input parameters in an attempt to optimize free drug level in tissue. Overall, this present study provides guidance on the application of plasma and tissue concentration information in PBPK/PD research in preclinical and clinical studies, which is in accordance with the recent literature.
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Poulin P, Chen YH, Ding X, Gould SE, Hop CE, Messick K, Oeh J, Liederer BM. Prediction of Drug Distribution in Subcutaneous Xenografts of Human Tumor Cell Lines and Healthy Tissues in Mouse: Application of the Tissue Composition-Based Model to Antineoplastic Drugs. J Pharm Sci 2015; 104:1508-21. [DOI: 10.1002/jps.24336] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 12/05/2014] [Accepted: 12/12/2014] [Indexed: 12/20/2022]
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Poulin P. Drug Distribution to Human Tissues: Prediction and Examination of the Basic Assumption in In Vivo Pharmacokinetics-Pharmacodynamics (PK/PD) Research. J Pharm Sci 2015; 104:2110-2118. [PMID: 25808270 DOI: 10.1002/jps.24427] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 12/25/2022]
Abstract
The tissue:plasma partition coefficients (Kp ) are good indicators of the extent of tissue distribution. Therefore, advanced tissue composition-based models were used to predict the Kp values of drugs under in vivo conditions on the basis of in vitro and physiological input data. These models, however, focus on animal tissues and do not challenge the predictions with human tissues for drugs. The first objective of this study was to predict the experimentally determined Kp values of seven human tissues for 26 drugs. In all, 95% of the predicted Kp values are within 2.5-fold error of the observed values in humans. Accordingly, these results suggest that the tissue composition-based model used in this study is able to provide accurate estimates of drug partitioning in the studied human tissues. Furthermore, as the Kp equals to the ratio of total concentration between tissue and plasma, or the ratio of unbound fraction between plasma (fup ) and tissue (fut ), this parameter Kp would deviate from the unity. Therefore, the second objective was to examine the corresponding relationships between fup and fut values experimentally determined in humans for several drugs. The results also indicate that fup may significantly deviate to fut ; the discrepancies are governed by the dissimilarities in the binding and ionization on both sides of the membrane, which were captured by the tissue composition-based model. Hence, this violated the basic assumption in in vivo pharmacokinetics-pharmacodynamics (PK/PD) research, since the free drug concentration in tissue and plasma was not equal particularly for the ionizable drugs due to the pH gradient effect on the fraction of unionized drug in plasma (fuip ) and tissue (fuit ) (i.e., fup × fuip × total plasma concentration = fut × fuit × total tissue concentration, and, hence, the free drug concentration in plasma and tissue differed by fuip/fuit). Therefore, this assumption should be adjusted for the ionized drugs, and, hence, a mathematical correction to the basic assumption of similar free drug concentration in plasma and tissues can be derived from the tissue composition-based model. Note that this assumption will be further challenged in a dynamic in vivo system in a companion manuscript. Overall, this study was a first attempt to predict the in vivo Kp values for specific human tissues by considering separately the effect of fup and fut , with the aim of facilitating the use of physiologically-based PK (PBPK) model in PK/PD studies.
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Davuluri G, Schiemann WP, Plow EF, Sossey-Alaoui K. Loss of WAVE3 sensitizes triple-negative breast cancers to chemotherapeutics by inhibiting the STAT-HIF-1α-mediated angiogenesis. JAKSTAT 2015; 3:e1009276. [PMID: 26413422 DOI: 10.1080/21623996.2015.1009276] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/09/2015] [Accepted: 01/13/2015] [Indexed: 01/10/2023] Open
Abstract
Chemoresistance allows for disease to recur and ultimately causes the death of most breast cancer patients. This scenario is particularly relevant in patients harboring triple-negative breast cancer (TNBC) tumors for which there are no effective FDA-approved drugs. However, a recent study determined that TNBCs can be segregated into 6 genetically distinct subtypes that do in fact exhibit differential rates of pathological complete response (pCR) to standard-of-care chemotherapies. Of these, the mesenchymal and mesenchymal stem-like subtypes of TNBCs exhibit the lowest rates of pCR when treated with standard-of-care chemotherapies. WAVE3 is an actin-cytoskeleton remodeling protein, and recent studies have highlighted a potential role for WAVE3 in promoting tumor progression and metastasis in TNBC. However, whether WAVE3 activity is involved in the development of chemoresistance in TNBCs remains unclear. Here we show that loss of WAVE3 expression resensitizes human TNBC cells to doxorubicin and docetaxel, as measured by increased apoptosis and cell death. We also show that WAVE3 knockdown in the chemotherapy-treated TNBC cells results in inhibition of STAT1 phosphorylation, as well as a significant decrease in expression levels of its downstream effector HIF-1α. Since HIF-1α is a major activator of VEGF-A production, and therefore a stimulator of tumor angiogenesis, loss of HIF-1α in the WAVE3-knockdown cells resulted in the inhibition the chemotherapy-mediated VEGF-A secretion and the downstream activation of angiogenesis, a phenomenon that often accompanies chemoresistance. Our data identify a critical role of WAVE3 in sensitizing TNBC to chemotherapy by inhibiting the STAT1→HIF-1α→VEGF-A signaling axis, and support the possibility that WAVE3 inhibition may be a promising target for TNBC cancer therapy.
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Affiliation(s)
- Gangarao Davuluri
- Department of Molecular Cardiology; Cleveland Clinic Lerner Institute ; Cleveland, OH USA
| | - William P Schiemann
- Case Comprehensive Cancer Center; Case Western Reserve University ; Cleveland, OH USA
| | - Edward F Plow
- Department of Molecular Cardiology; Cleveland Clinic Lerner Institute ; Cleveland, OH USA
| | - Khalid Sossey-Alaoui
- Department of Molecular Cardiology; Cleveland Clinic Lerner Institute ; Cleveland, OH USA
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Deng S, Wang C, Zhang W, Gao W, Fan A, Zhang Q, Zhang Y, Liu Q, Li N, Liu Q, Zhao J, Li C, Wen X, Zhao D, Chen X. Effect of triacontanol on the pharmacokinetics of docetaxel in rats associated with induction of cytochrome P450 3A1/2. Xenobiotica 2013; 44:583-90. [DOI: 10.3109/00498254.2013.870364] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Emond C, Sanders JM, Wikoff D, Birnbaum LS. Proposed mechanistic description of dose-dependent BDE-47 urinary elimination in mice using a physiologically based pharmacokinetic model. Toxicol Appl Pharmacol 2013; 273:335-44. [PMID: 24055880 DOI: 10.1016/j.taap.2013.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 08/31/2013] [Accepted: 09/09/2013] [Indexed: 11/29/2022]
Abstract
Polybrominated diphenyl ethers (PBDEs) have been used in a wide variety of consumer applications as additive flame retardants. In North America, scientists have noted continuing increases in the levels of PBDE congeners measured in human serum. Some recent studies have found that PBDEs are associated with adverse health effects in humans, in experimental animals, and wildlife. This laboratory previously demonstrated that urinary elimination of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is saturable at high doses in mice; however, this dose-dependent urinary elimination has not been observed in adult rats or immature mice. Thus, the primary objective of this study was to examine the mechanism of urinary elimination of BDE-47 in adult mice using a physiologically based pharmacokinetic (PBPK) model. To support this objective, additional laboratory data were collected to evaluate the predictions of the PBPK model using novel information from adult multi-drug resistance 1a/b knockout mice. Using the PBPK model, the roles of mouse major urinary protein (a blood protein carrier) and P-glycoprotein (an apical membrane transporter in proximal tubule cells in the kidneys, brain, intestines, and liver) were investigated in BDE-47 elimination. The resulting model and new data supported the major role of m-MUP in excretion of BDE-47 in the urine of adult mice, and a lesser role of P-gp as a transporter of BDE-47 in mice. This work expands the knowledge of BDE-47 kinetics between species and provides information for determining the relevancy of these data for human risk assessment purposes.
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Affiliation(s)
- Claude Emond
- BioSimulation Consulting Inc., Newark, DE, USA; Departments of Environmental and Occupational Health, Medicine Faculty, University of Montreal, Montreal, Quebec, Canada.
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