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Pitcher A, Lamata P, Krittian SB, Nordslettern DA, Bissell MM, Francis JM, Cassar TE, Barker AJ, Markl M, Neubauer S, Smith N. Towards a comprehensive description of relative aortic pressure: insights from 4D flow CMR. J Cardiovasc Magn Reson 2013. [PMCID: PMC3559897 DOI: 10.1186/1532-429x-15-s1-p243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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202
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Entezari P, Schnell S, Mahadevia RJ, Rinewalt D, Davarpanah AH, Malaisrie SC, McCarthy P, Collins J, Carr J, Markl M, Barker AJ. From unicuspid to quadricuspid: the impact of aortic valve morphology on 3D hemodynamics. J Cardiovasc Magn Reson 2013. [PMCID: PMC3559632 DOI: 10.1186/1532-429x-15-s1-o79] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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203
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Mahadevia RJ, Schnell S, Entezari P, Rinewalt D, Kansal P, Malaisrie SC, McCarthy P, Collins J, Carr J, Barker AJ, Markl M. 4D flow MRI demonstrates altered aortic hemodynamics in patients with right-left and right-noncoronary bicuspid aortic valve fusion patterns. J Cardiovasc Magn Reson 2013. [PMCID: PMC3559505 DOI: 10.1186/1532-429x-15-s1-m8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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204
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Jarvis KB, Schnell S, Gabbour M, Barker AJ, Lorenz R, Carr J, Robinson JD, Popescu AR, de Freitas RA, Rigsby C, Markl M. In vivo quantification of blood mixing in single ventricle patients with Fontan circulation using 4D flow MRI. J Cardiovasc Magn Reson 2013. [PMCID: PMC3559408 DOI: 10.1186/1532-429x-15-s1-e88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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205
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Bissell MM, Hess AT, Glaze SJ, Pitcher A, Robson MD, Barker AJ, Myerson S, Neubauer S. Cusp fusion pattern in bicuspid aortic valve disease predicts severity of aortic flow abnormalities. J Cardiovasc Magn Reson 2013. [PMCID: PMC3559570 DOI: 10.1186/1532-429x-15-s1-o69] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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206
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Garcia J, Barker AJ, Schnell S, Entezari P, Mahadevia RJ, Pibarot P, Carr J, Markl M. 4D flow jet shear layer detection method for the measurement of effective orifice area and assessment of aortic stenosis severity. J Cardiovasc Magn Reson 2013. [PMCID: PMC3559931 DOI: 10.1186/1532-429x-15-s1-p241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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207
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Allen BD, Barker AJ, Carr JC, Silverberg RA, Markl M. Time-resolved three-dimensional phase contrast MRI evaluation of bicuspid aortic valve and coarctation of the aorta. Eur Heart J Cardiovasc Imaging 2012; 14:399. [PMID: 23111692 DOI: 10.1093/ehjci/jes225] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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208
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Levack M, Witschey WR, McGarvey JR, Kondo N, Barker AJ, Markl M, Gorman JH, Pilla JJ, Gorman RC. Alterations in intracardiac flow patterns affect mitral leaflet dynamics in ischemic mitral regurgitation. J Am Coll Surg 2012. [DOI: 10.1016/j.jamcollsurg.2012.06.112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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209
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Barker AJ, Markl M, Bürk J, Lorenz R, Bock J, Bauer S, Schulz-Menger J, von Knobelsdorff-Brenkenhoff F. Bicuspid aortic valve is associated with altered wall shear stress in the ascending aorta. Circ Cardiovasc Imaging 2012; 5:457-66. [PMID: 22730420 DOI: 10.1161/circimaging.112.973370] [Citation(s) in RCA: 320] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Hemodynamics may play a role contributing to the progression of bicuspid aortic valve (BAV) aortopathy. This study measured the impact of BAV on the distribution of regional aortic wall shear stress (WSS) compared with control cohorts. METHODS AND RESULTS Local WSS distribution was measured in the thoracic aorta of 60 subjects using 4-dimensional (4D) flow-sensitive magnetic resonance imaging. WSS analysis included 15 BAV patients: 12 with fusion of the right-left coronary cusp (6 stenotic) and 3 with fusion of the right and noncoronary cusp. The right-left BAV cohort was compared with healthy subjects (n=15), age-appropriate subjects (n=15), and age-/aorta size-controlled subjects (n=15). Compared with the age-appropriate and age-/aorta size-matched controls, WSS patterns in the right-left BAV ascending aorta were significantly elevated, independent of stenosis severity (peak WSS=0.9 ± 0.3 N/m(2) compared with 0.4 ± 0.3 N/m(2) in age-/aorta size-controlled subjects; P<0.001). Time-resolved (cine) 2D images of the bicuspid valves were coregistered with 4D flow data, directly linking cusp fusion pattern to a distinct ascending aortic flow jet pattern. The observation of right-anterior ascending aorta wall/jet impingement in right-left BAV patients corresponded to regions with statistically elevated WSS. Alternative jetting patterns were observed in the right and noncoronary cusp fusion patients. CONCLUSIONS The results of this study demonstrate that bicuspid valves induced significantly altered ascending aorta hemodynamics compared with age- and size-matched controls with tricuspid valves. Specifically, the expression of increased and asymmetric WSS at the aorta wall was related to ascending aortic flow jet patterns, which were influenced by the BAV fusion pattern.
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Barker AJ, Staehle F, Bock J, Jung BA, Markl M. Analysis of complex cardiovascular flow with three-component acceleration-encoded MRI. Magn Reson Med 2011; 67:50-61. [DOI: 10.1002/mrm.22974] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 03/18/2011] [Accepted: 04/04/2011] [Indexed: 11/06/2022]
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211
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Aizawa K, Gates PE, Strain WD, Gosling OE, Mazzaro L, Zhang F, Barker AJ, Fulford J, Shore AC, Bellenger NG, Lanning C, Shandas R. Arterial Wall Shear Stress Measurement In Vivo Using Echo Particle Image Velocimetry (Echo PIV). Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402067.74813.a0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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212
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Bock J, Frydrychowicz A, Lorenz R, Hirtler D, Barker AJ, Johnson KM, Arnold R, Burkhardt H, Hennig J, Markl M. In vivo noninvasive 4D pressure difference mapping in the human aorta: phantom comparison and application in healthy volunteers and patients. Magn Reson Med 2011; 66:1079-88. [PMID: 21437978 DOI: 10.1002/mrm.22907] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 02/14/2011] [Accepted: 02/15/2011] [Indexed: 12/21/2022]
Abstract
In this work, we present a systematic phantom comparison and clinical application of noninvasive pressure difference mapping in the human aorta based on time-resolved 3D phase contrast data. Relative pressure differences were calculated based on integration and iterative refinement of pressure gradients derived from MR-based three-directional velocity vector fields (flow-sensitive 4D MRI with spatial/temporal resolution ∼ 2.1 mm(3)/40 ms) using the Navier-Stokes equation. After in vitro study using a stenosis phantom, time-resolved 3D pressure gradients were systematically evaluated in the thoracic aorta in a group of 12 healthy subjects and 6 patients after repair for aortic coarctation. Results from the phantom study showed good agreement with expected values and standard methods (Bernoulli). Data of healthy subjects showed good intersubject consistency and good agreement with the literature. In patients, pressure waveforms showed elevated peak values. Pressure gradients across the stenosis were compared with reference measurements from Doppler ultrasound. The MRI findings demonstrated a significant correlation (r = 0.96, P < 0.05) but moderate underestimation (14.7% ± 15.5%) compared with ultrasound when the maximum pressure difference for all possible paths connecting proximal and distal locations of the stenosis were used. This study demonstrates the potential of the applied approach to derive additional quantitative information such as pressure gradients from time-resolved 3D phase contrast MRI.
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213
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Zhang F, Lanning C, Mazzaro L, Barker AJ, Gates P, Strain WD, Fulford J, Gosling OE, Shore AC, Bellenger NG, Rech B, Chen J, Chen J, Shandas R. In vitro and preliminary in vivo validation of echo particle image velocimetry in carotid vascular imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:450-64. [PMID: 21316562 PMCID: PMC3449315 DOI: 10.1016/j.ultrasmedbio.2010.11.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 05/11/2023]
Abstract
Noninvasive, easy-to-use and accurate measurements of wall shear stress (WSS) in human blood vessels have always been challenging in clinical applications. Echo particle image velocimetry (Echo PIV) has shown promise for clinical measurements of local hemodynamics and wall shear rate. Thus far, however, the method has only been validated under simple flow conditions. In this study, we validated Echo PIV under in vitro and in vivo conditions. For in vitro validation, we used an anatomically correct, compliant carotid bifurcation flow phantom with pulsatile flow conditions, using optical particle image velocimetry (optical PIV) as the reference standard. For in vivo validation, we compared Echo PIV-derived 2-D velocity fields obtained at the carotid bifurcation in five normal subjects against phase-contrast magnetic resonance imaging (PC-MRI)-derived velocity measurements obtained at the same locations. For both studies, time-dependent, 2-D, two-component velocity vectors; peak/centerline velocity, flow rate and wall shear rate (WSR) waveforms at the common carotid artery (CCA), carotid bifurcation and distal internal carotid artery (ICA) were examined. Linear regression, correlation analysis and Bland-Altman analysis were used to quantify the agreement of different waveforms measured by the two techniques. In vitro results showed that Echo PIV produced good images of time-dependent velocity vector maps over the cardiac cycle with excellent temporal (up to 0.7 ms) and spatial (∼0.5 mm) resolutions and quality, comparable with optical PIV results. Further, good agreement was found between Echo PIV and optical PIV results for velocity and WSR measurements. In vivo results also showed good agreement between Echo PIV velocities and phase contrast MRI velocities. We conclude that Echo PIV provides accurate velocity vector and WSR measurements in the carotid bifurcation and has significant potential as a clinical tool for cardiovascular hemodynamics evaluation.
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214
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Barker AJ, Markl M. The role of hemodynamics in bicuspid aortic valve disease. Eur J Cardiothorac Surg 2011; 39:805-6. [PMID: 21339071 DOI: 10.1016/j.ejcts.2011.01.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 12/17/2010] [Accepted: 01/05/2011] [Indexed: 12/17/2022] Open
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215
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Barker AJ, Lanning C, Shandas R. Quantification of hemodynamic wall shear stress in patients with bicuspid aortic valve using phase-contrast MRI. Ann Biomed Eng 2009; 38:788-800. [PMID: 19953319 DOI: 10.1007/s10439-009-9854-3] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Accepted: 11/19/2009] [Indexed: 11/25/2022]
Abstract
Bicuspid aortic valve (BAV) is often concomitant with aortic dilatation, aneurysm, and dissection. This valve lesion and its complications may affect positional and temporal wall shear stress (WSS), a parameter reported to regulate transcriptional events in vascular remodeling. Thus, this pilot study seeks to determine if the WSS in the ascending aorta (AAo) of BAV patients differs from control patients. Phase-contrast magnetic resonance imaging (PC-MRI) was used to perform flow analysis at the level of the AAo in 15 BAV and 15 control patients. Measurement of the aorta dimensions, flow rates, regurgitant fraction (RF), flow reversal ratio (FRR), temporal and spatial WSS, and shear range indices (SRI) were performed. The BAV and control group showed a significant difference between the circumferentially averaged WSS (p=0.03) and positional WSS at systole (minimum p<0.001). Regressions found that SRI (r=0.77, p<0.001), RF (r=0.68, p<0.001), and WSS at systole (r=0.66, p<0.001) were correlated to AAo size. The spatial distribution and magnitude of systolic WSS in BAV patients (-6.7+/-4.3 dynes/cm2) differed significantly from control patients (-11.5+/-6.6 dynes/cm2, p=0.03). The SRI metric, a measure of shear symmetry along the lumen circumference, was also significantly different (p=0.006) and indicated a heterogenic pattern of dilatation in the BAV patients.
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216
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Cage B, Russek SE, Shoemaker R, Barker AJ, Stoldt C, Ramachandaran V, Dalal NS. The utility of the single-molecule magnet Fe8 as a magnetic resonance imaging contrast agent over a broad range of concentration. Polyhedron 2007. [DOI: 10.1016/j.poly.2006.12.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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217
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Barker AJ, Gibson KH, Grundy W, Godfrey AA, Barlow JJ, Healy MP, Woodburn JR, Ashton SE, Curry BJ, Scarlett L, Henthorn L, Richards L. Studies leading to the identification of ZD1839 (IRESSA): an orally active, selective epidermal growth factor receptor tyrosine kinase inhibitor targeted to the treatment of cancer. Bioorg Med Chem Lett 2001; 11:1911-4. [PMID: 11459659 DOI: 10.1016/s0960-894x(01)00344-4] [Citation(s) in RCA: 399] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This paper describes the development of the epidermal growth factor receptor tyrosine kinase inhibitor ZD1839 from a lead series of 4-anilinoquinazoline compounds. ZD1839 has suitable properties for use as a clinically effective drug and shows activity against human tumours. In particular, the use of pharmacokinetic data in the development of ZD1839 is discussed.
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218
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Barker AJ. The effect of melting on the multiphonon infrared absorption spectra of KBr, NaCl and LiF. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/5/16/028] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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219
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Barker AJ. A compact, windowless reflectance furnace for infrared studies of corrosive melts. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3735/6/3/014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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220
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Wakeling AE, Barker AJ, Davies DH, Brown DS, Green LR, Cartlidge SA, Woodburn JR. Specific inhibition of epidermal growth factor receptor tyrosine kinase by 4-anilinoquinazolines. Breast Cancer Res Treat 1996; 38:67-73. [PMID: 8825124 DOI: 10.1007/bf01803785] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Since the mitogenic action of EGF is mediated by ligand-induced autophosphorylation of the EGF receptor (EGFR), and EGFR is commonly overexpressed in solid human tumours, inhibitors of receptor tyrosine kinase activity (RTK) could prove to be effective antitumour agents. Screening of a compound library using an EGF-RTK enzyme prepared from human tumour derived A431 cells identified a series of potent (IC50 < 1 microM) enzyme inhibitors. These inhibitors are quinazolines bearing a variety of substituted anilines at the 4-position. The most potent 4-anilinoquinazolines (IC50 approximately equal to 20 nM) have small non-polar meta substituents on the aniline ring, and are competitive with ATP and non-competitive with substrate. The growth inhibitory activity of these agents was assessed in vitro using KB cells (human oral squamous tumour) grown in the absence or presence of EGF. A selected compound, 4-(3-chloroanilino)quinazoline (CAQ), inhibited EGF-stimulated growth in a concentration dependent manner and complete blockade was observed at concentrations (1-10 microM) which had no effect on basal growth. Selectivity of growth inhibition by CAQ was further exemplified in IGF1-stimulated KB cells where no effect was detected at concentrations which completely blocked EGF-stimulated growth. Similarly, CAQ blocked TGF alpha-stimulated growth in MCF-7 human breast cancer cells without affecting insulin-stimulated growth. These studies define a novel class of EGF-RTK inhibitors which are also potent and selective inhibitors of EGF-stimulated human tumour cell growth in vitro.
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221
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Low K, Barker AJ, Vincent JM. A thirteen-year-old with a painful, swollen foot and eosinophilia. Pediatr Infect Dis J 1995; 14:820, 825-6. [PMID: 8559642 DOI: 10.1097/00006454-199509000-00024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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222
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Marsham PR, Jackman AL, Barker AJ, Boyle FT, Pegg SJ, Wardleworth JM, Kimbell R, O'Connor BM, Calvert AH, Hughes LR. Quinazoline antifolate thymidylate synthase inhibitors: replacement of glutamic acid in the C2-methyl series. J Med Chem 1995; 38:994-1004. [PMID: 7699716 DOI: 10.1021/jm00006a019] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The synthesis of a series of analogues of the potent thymidylate synthase (TS) inhibitor N-[4-[N-[(3,4-dihydro-2-methyl-4-oxo-6- quinazolinyl)methyl]-N-prop-2-ynylamino]benzoyl]-L-glutamic acid (ICI 198583, 1) is described in which the glutamic acid residue has been replaced by other alpha-amino acids. Most of these analogues were prepared by coupling of tert-butyl-4-(prop-2-ynylamino)benzoate (37) with 6-(bromomethyl)-3,4-dihydro-2-methyl-4-oxoquinazoline (34) followed by deprotection of the tert-butyl ester to the acid and azide-mediated coupling to the appropriate amino acid or amino acid ester. In cases where the amino acid ester was unreactive with the acid azide, a modification was used in which the quinazolinone moiety was protected as its 3-(pivaloyloxy)methyl derivative. This permitted the generation of the more reactive acid chloride of the p-aminobenzoate unit. In general these modifications result in compounds that have equivalent potency to 1 as inhibitors of isolated TS except where the amino acid lacks a lipophilic alpha-substituent. These compounds appear to require the reduced folate carrier (RFC) for transport into cells, but since they are not converted intracellularly into polyglutamated forms, they have a lower level of cytotoxicity compared to 1. The removal of the alpha-carboxylic acid has given a second set of analogues of 1 which contain simple alkyl amide, benzyl, substituted benzyl, and heterocyclic benzyl amide derivatives. These are considerably less potent than 1 as TS inhibitors but display 1-10 microM cytotoxicities due to the fact that they do not require RFC transport and can presumably readily enter cells by passive diffusion through the cell membrane. Molecular modeling and NMR studies indicated that the incorporation of, respectively, 7-methyl and 2'-fluoro substituents would favor the optimum conformation of these molecules for interaction with the TS enzyme. Accordingly, these substituents were incorporated into selected examples to give the series of analogues 47-55. These all show enhanced (approximately 10-fold) inhibition of TS compared to their unsubstituted counterparts. In the substituted benzylamides (51, 52) and heterocyclic benzyl amides (53-55) the ability to enter cells by passive diffusion results in highly potent (< 1 microM) cytotoxic agents.
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223
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Cashman TM, Hassell LH, Barker AJ, Funderburk LK. Operation tropic refuge: the East Wood rescue. Mil Med 1994; 159:723-9. [PMID: 7723994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The U.S. Coast Guard rescued 525 Chinese nationals and ten Indonesian crewmen from the disabled motor vessel East Wood. They were participating in a human smuggling operation. Subjected to a trying ordeal at sea, these individuals were at great risk to life and health but survived remarkably well because of their good health, age, and mutual cooperation. The U.S. military organized the joint task force, Operation Provide Refuge, to provide humanitarian aid. The task force rapidly mobilized resources to support camp development on Kwajalein Island and provide nutrition and health care to the stranded travelers. Preventive Medicine personnel, called in at the beginning of the operation, helped develop a healthy campsite, which contributed to a relatively uneventful refugee experience. Close liaison with the local medical resources on Kwajalein was essential to the success of the operation.
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224
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Monge A, Narro S, Martínez-Crespo FJ, de Ceráin A, Hamilton E, Barker AJ. Hypoxia-selective antitumor agents derived from 1,9-diazaanthracene. Eur J Med Chem 1994. [DOI: 10.1016/0223-5234(94)90071-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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225
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Warner P, Barker AJ, Jackman AL, Burrows KD, Roberts N, Bishop JA, O'Connor BM, Hughes LR. Quinoline antifolate thymidylate synthase inhibitors: variation of the C2- and C4-substituents. J Med Chem 1992; 35:2761-8. [PMID: 1495009 DOI: 10.1021/jm00093a007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Modifications to the bicyclic ring system of the potent thymidylate synthase (TS) inhibitor N-[4-[N-[(2-amino-3,4-dihydro-4-oxo-6- quinazolinyl)methyl]-N-prop-2-ynylamino]benzoyl]-L-glutamic acid (1, CB3717) have led to the synthesis of a series of quinoline antifolates bearing a variety of substituents at the C2 and C4 positions. In general the synthetic route involved the coupling of the appropriate diethyl N-[4-(prop-2-ynylamino)benzoyl]-L-glutamate with a disubstituted 6-(bromomethyl)quinoline followed by deprotection using mild alkali. The compounds were tested as inhibitors of partially purified L1210 TS. As a measure of cytotoxicity, the compounds were tested for their inhibition of the growth of L1210 cells in culture. Good enzyme inhibition and cytotoxicity were found for compounds containing chloro, amino, or methyl substituents at the C2 position with chloro or bromo substituents at C4. The effect on enzyme inhibition of varying the N10 substituent of 2h was similar to that observed in the quinazolinone-containing antifolates, indicating that the quinoline compounds may be interacting with the enzyme in a similar way to the quinazolinones. Also, the introduction of a 2'-fluoro substituent into the benzoyl ring of several of the quinoline antifolates led to an increase in both TS inhibition and the inhibition of L1210 cell growth. These data demonstrate that the N3-H of the pyrimidine ring of the quinazolinone antifolates is not required for binding to TS if appropriate substituents are placed at the C2 and C4 positions of the bicyclic ring system.
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