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Pixelated Microfluidics for Drug Screening on Tumour Spheroids and Ex Vivo Microdissected Tumour Explants. Cancers (Basel) 2023; 15:cancers15041060. [PMID: 36831403 PMCID: PMC9954565 DOI: 10.3390/cancers15041060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/27/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
Anticancer drugs have the lowest success rate of approval in drug development programs. Thus, preclinical assays that closely predict the clinical responses to drugs are of utmost importance in both clinical oncology and pharmaceutical research. 3D tumour models preserve the tumoral architecture and are cost- and time-efficient. However, the short-term longevity, limited throughput, and limitations of live imaging of these models have so far driven researchers towards less realistic tumour models such as monolayer cell cultures. Here, we present an open-space microfluidic drug screening platform that enables the formation, culture, and multiplexed delivery of several reagents to various 3D tumour models, namely cancer cell line spheroids and ex vivo primary tumour fragments. Our platform utilizes a microfluidic pixelated chemical display that creates isolated adjacent flow sub-units of reagents, which we refer to as fluidic 'pixels', over tumour models in a contact-free fashion. Up to nine different treatment conditions can be tested over 144 samples in a single experiment. We provide a proof-of-concept application by staining fixed and live tumour models with multiple cellular dyes. Furthermore, we demonstrate that the response of the tumour models to biological stimuli can be assessed using the platform. Upscaling the microfluidic platform to larger areas can lead to higher throughputs, and thus will have a significant impact on developing treatments for cancer.
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2
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Khera E, Dong S, Huang H, de Bever L, Delft FLV, Thurber GM. Cellular-Resolution Imaging of Bystander Payload Tissue Penetration from Antibody-Drug Conjugates. Mol Cancer Ther 2021; 21:310-321. [PMID: 34911819 DOI: 10.1158/1535-7163.mct-21-0580] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/16/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022]
Abstract
After several notable clinical failures in early generations, antibody-drug conjugates (ADCs) have made significant gains with seven new FDA-approvals within the last 3 years. These successes have been driven by a shift towards mechanistically informed ADC design, where the payload, linker, drug-to-antibody ratio, and conjugation are increasingly tailored to a specific target and clinical indication. However, fundamental aspects needed for design, such as payload distribution, remain incompletely understood. Payloads are often classified as 'bystander' or 'non-bystander' depending on their ability to diffuse out of targeted cells into adjacent cells that may be antigen negative or more distant from tumor vessels, helping to overcome heterogeneous distribution. Seven of the eleven FDA-approved ADCs employ these bystander payloads, but the depth of penetration and cytotoxic effects as a function of physicochemical properties and mechanism of action have not been fully characterized. Here, we utilized tumor spheroids and pharmacodynamic marker staining to quantify tissue penetration of the three major classes of agents: microtubule inhibitors, DNA-damaging agents, and topoisomerase inhibitors. PAMPA data and co-culture assays were performed to compare to the 3D tissue culture data. The results demonstrate a spectrum in bystander potential and tissue penetration depending on the physicochemical properties and potency of the payload. Generally, directly targeted cells show a greater response even with bystander payloads, consistent with the benefit of deeper ADC penetration. These results are compared to computational simulations to help scale the data from in vitro and preclinical animal models to the clinic.
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Affiliation(s)
- Eshita Khera
- Chemical Engineering, University of Michigan–Ann Arbor
| | - Shujun Dong
- Chemical Engineering, University of Michigan–Ann Arbor
| | - Haolong Huang
- Chemical Engineering, University of Michigan–Ann Arbor
| | | | | | - Greg M Thurber
- Chemical Engineering, Biomedical Engineering, University of Michigan–Ann Arbor
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3
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Vilaplana-Lopera N, Besh M, Moon EJ. Targeting Hypoxia: Revival of Old Remedies. Biomolecules 2021; 11:1604. [PMID: 34827602 PMCID: PMC8615589 DOI: 10.3390/biom11111604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 12/14/2022] Open
Abstract
Tumour hypoxia is significantly correlated with patient survival and treatment outcomes. At the molecular level, hypoxia is a major driving factor for tumour progression and aggressiveness. Despite the accumulative scientific and clinical efforts to target hypoxia, there is still a need to find specific treatments for tumour hypoxia. In this review, we discuss a variety of approaches to alter the low oxygen tumour microenvironment or hypoxia pathways including carbogen breathing, hyperthermia, hypoxia-activated prodrugs, tumour metabolism and hypoxia-inducible factor (HIF) inhibitors. The recent advances in technology and biological understanding reveal the importance of revisiting old therapeutic regimens and repurposing their uses clinically.
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Affiliation(s)
| | | | - Eui Jung Moon
- Department of Oncology, MRC Oxford Institute for Radiation Oncology, University of Oxford, Headington OX3 7DQ, UK; (N.V.-L.); (M.B.)
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4
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Cicchese JM, Dartois V, Kirschner DE, Linderman JJ. Both Pharmacokinetic Variability and Granuloma Heterogeneity Impact the Ability of the First-Line Antibiotics to Sterilize Tuberculosis Granulomas. Front Pharmacol 2020; 11:333. [PMID: 32265707 PMCID: PMC7105635 DOI: 10.3389/fphar.2020.00333] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
Tuberculosis (TB) remains as one of the world's deadliest infectious diseases despite the use of standardized antibiotic therapies. Recommended therapy for drug-susceptible TB is up to 6 months of antibiotics. Factors that contribute to lengthy regimens include antibiotic underexposure in lesions due to poor pharmacokinetics (PK) and complex granuloma compositions, but it is difficult to quantify how individual antibiotics are affected by these factors and to what extent these impact treatments. We use our next-generation multi-scale computational model to simulate granuloma formation and function together with antibiotic pharmacokinetics and pharmacodynamics, allowing us to predict conditions leading to granuloma sterilization. In this work, we focus on how PK variability, determined from human PK data, and granuloma heterogeneity each quantitatively impact granuloma sterilization. We focus on treatment with the standard regimen for TB of four first-line antibiotics: isoniazid, rifampin, ethambutol, and pyrazinamide. We find that low levels of antibiotic concentration due to naturally occurring PK variability and complex granulomas leads to longer granuloma sterilization times. Additionally, the ability of antibiotics to distribute in granulomas and kill different subpopulations of bacteria contributes to their specialization in the more efficacious combination therapy. These results can inform strategies to improve antibiotic therapy for TB.
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Affiliation(s)
- Joseph M Cicchese
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, United States
| | - Véronique Dartois
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States.,Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, United States
| | - Denise E Kirschner
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Jennifer J Linderman
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, United States
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5
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Mao X, McManaway S, Jaiswal JK, Hong CR, Wilson WR, Hicks KO. Schedule-dependent potentiation of chemotherapy drugs by the hypoxia-activated prodrug SN30000. Cancer Biol Ther 2019; 20:1258-1269. [PMID: 31131698 DOI: 10.1080/15384047.2019.1617570] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hypoxia-activated prodrugs (HAPs) are hypothesized to improve the therapeutic index of chemotherapy drugs that are ineffective against tumor cells in hypoxic microenvironments. SN30000 (CEN-209) is a benzotriazine di-N-oxide HAP that potentiates radiotherapy in preclinical models, but its combination with chemotherapy has not been explored. Here we apply multiple models (monolayers, multicellular spheroids and tumor xenografts) to identify promising SN30000/chemotherapy combinations (with chemotherapy drugs before, during or after SN30000 exposure). SN30000, unlike doxorubicin, cisplatin, gemcitabine or paclitaxel, was more active against cells in spheroids than monolayers by clonogenic assay. Combinations of SN30000 and chemotherapy drugs in HCT116/GFP and SiHa spheroids demonstrated hypoxia-and schedule-dependent potentiation of gemcitabine or doxorubicin in growth inhibition and clonogenic assays. Co-administration with SN30000 suppressed clearance of gemcitabine in NIH-III mice, likely due to SN30000-induced hypothermia which also modulated extravascular transport of gemcitabine in tumor tissue as assessed from its diffusion through HCT116 multicellular layer cultures. Despite these systemic effects, the same schedules that gave therapeutic synergy in spheroids (SN30000 3 h before or during gemcitabine, but not gemcitabine 3 h before SN30000) enhanced growth delay of HCT116 xenografts without increasing host toxicity. Identification of hypoxic and S-phase cells by immunohistochemistry and flow cytometry established that hypoxic cells initially spared by gemcitabine subsequently reoxygenate and re-enter the cell cycle, and that this repopulation is prevented by SN30000 only when administered with or before gemcitabine. This illustrates the value of spheroids in modeling tumor microenvironment-dependent drug interactions, and the potential of HAPs for overcoming hypoxia-mediated drug resistance.
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Affiliation(s)
- Xinjian Mao
- Auckland Cancer Society Research Centre, University of Auckland , Auckland , New Zealand
| | - Sarah McManaway
- Auckland Cancer Society Research Centre, University of Auckland , Auckland , New Zealand
| | - Jagdish K Jaiswal
- Auckland Cancer Society Research Centre, University of Auckland , Auckland , New Zealand
| | - Cho R Hong
- Auckland Cancer Society Research Centre, University of Auckland , Auckland , New Zealand
| | - William R Wilson
- Auckland Cancer Society Research Centre, University of Auckland , Auckland , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , Auckland , New Zealand
| | - Kevin O Hicks
- Auckland Cancer Society Research Centre, University of Auckland , Auckland , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , Auckland , New Zealand
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6
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Taylor E, Gottwald J, Yeung I, Keller H, Milosevic M, Dhani NC, Siddiqui I, Hedley DW, Jaffray DA. Impact of tissue transport on PET hypoxia quantification in pancreatic tumours. EJNMMI Res 2017; 7:101. [PMID: 29273939 PMCID: PMC5741574 DOI: 10.1186/s13550-017-0347-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 11/28/2017] [Indexed: 12/26/2022] Open
Abstract
Background The clinical impact of hypoxia in solid tumours is indisputable and yet questions about the sensitivity of hypoxia-PET imaging have impeded its uptake into routine clinical practice. Notably, the binding rate of hypoxia-sensitive PET tracers is slow, comparable to the rate of diffusive equilibration in some tissue types, including mucinous and necrotic tissue. This means that tracer uptake on the scale of a PET imaging voxel—large enough to include such tissue and hypoxic cells—can be as much determined by tissue transport properties as it is by hypoxia. Dynamic PET imaging of 20 patients with pancreatic ductal adenocarcinoma was used to assess the impact of transport on surrogate metrics of hypoxia: the tumour-to-blood ratio [TBR(t)] at time t post-tracer injection and the trapping rate k3 inferred from a two-tissue compartment model. Transport quantities obtained from this model included the vascular influx and efflux rate coefficients, k1 and k2, and the distribution volume vd≡k1/(k2+k3). Results Correlations between voxel- and whole tumour-scale k3 and TBR values were weak to modest: the population average of the Pearson correlation coefficients (r) between voxel-scale k3 and TBR (1 h) [TBR(2 h)] values was 0.10 [0.01] in the 20 patients, while the correlation between tumour-scale k3 and TBR(2 h) values was 0.58. Using Patlak’s formula to correct uptake for the distribution volume, correlations became strong (r=0.80[0.52] and r=0.93, respectively). The distribution volume was substantially below unity for a large fraction of tumours studied, with vd ranging from 0.68 to 1 (population average, 0.85). Surprisingly, k3 values were strongly correlated with vd in all patients. A model was proposed to explain this in which k3 is a combination of the hypoxia-sensitive tracer binding rate kb and the rate keq of equilibration in slow-equilibrating regions occupying a volume fraction 1−vd of the imaged tissue. This model was used to calculate the proposed hypoxia surrogate marker kb. Conclusions Hypoxia-sensitive PET tracers are slow to reach diffusive equilibrium in a substantial fraction of pancreatic tumours, confounding quantification of hypoxia using both static (TBR) and dynamic (k3) PET imaging. TBR is reduced by distribution volume effects and k3 is enhanced by slow equilibration. We proposed a novel model to quantify tissue transport properties and hypoxia-sensitive tracer binding in order to improve the sensitivity of hypoxia-PET imaging. Electronic supplementary material The online version of this article (doi:10.1186/s13550-017-0347-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Edward Taylor
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada. .,Techna Institute, University Health Network, Toronto, Canada.
| | - Jennifer Gottwald
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Ivan Yeung
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Harald Keller
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Michael Milosevic
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Neesha C Dhani
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, Canada
| | - Iram Siddiqui
- Department of Pathology, Hospital for Sick Children, Toronto, Canada
| | - David W Hedley
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, Canada
| | - David A Jaffray
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Techna Institute, University Health Network, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Canada.,Institute for Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
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Abstract
The effectiveness of anticancer drugs in treating a solid tumour is dependent on delivery of the drug to virtually all cancer cells in the tumour. The distribution of drug in tumour tissue depends on the plasma pharmacokinetics, the structure and function of the tumour vasculature and the transport properties of the drug as it moves through microvessel walls and in the extravascular tissue. The aim of this Review is to provide a broad, balanced perspective on the current understanding of drug transport to tumour cells and on the progress in developing methods to enhance drug delivery. First, the fundamental processes of solute transport in blood and tissue by convection and diffusion are reviewed, including the dependence of penetration distance from vessels into tissue on solute binding or uptake in tissue. The effects of the abnormal characteristics of tumour vasculature and extravascular tissue on these transport properties are then discussed. Finally, methods for overcoming limitations in drug transport and thereby achieving improved therapeutic results are surveyed.
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Affiliation(s)
- Mark W Dewhirst
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona 85724, USA
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8
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Sun H, Merrill D, An R, Turek J, Matei D, Nolte DD. Biodynamic imaging for phenotypic profiling of three-dimensional tissue culture. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:16007. [PMID: 28301634 PMCID: PMC5221565 DOI: 10.1117/1.jbo.22.1.016007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/28/2016] [Indexed: 05/04/2023]
Abstract
Three-dimensional (3-D) tissue culture represents a more biologically relevant environment for testing new drugs compared to conventional two-dimensional cancer cell culture models. Biodynamic imaging is a high-content 3-D optical imaging technology based on low-coherence interferometry and digital holography that uses dynamic speckle as high-content image contrast to probe deep inside 3-D tissue. Speckle contrast is shown to be a scaling function of the acquisition time relative to the persistence time of intracellular transport and hence provides a measure of cellular activity. Cellular responses of 3-D multicellular spheroids to paclitaxel are compared among three different growth techniques: rotating bioreactor (BR), hanging-drop (HD), and nonadherent (U-bottom, UB) plate spheroids, compared with ex vivo living tissues. HD spheroids have the most homogeneous tissue, whereas BR spheroids display large sample-to-sample variability as well as spatial heterogeneity. The responses of BR-grown tumor spheroids to paclitaxel are more similar to those of ex vivo biopsies than the responses of spheroids grown using HD or plate methods. The rate of mitosis inhibition by application of taxol is measured through tissue dynamics spectroscopic imaging, demonstrating the ability to monitor antimitotic chemotherapy. These results illustrate the potential use of low-coherence digital holography for 3-D pharmaceutical screening applications.
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Affiliation(s)
- Hao Sun
- Purdue University, Department of Physics, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
| | - Daniel Merrill
- Purdue University, Department of Physics, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
| | - Ran An
- Animated Dynamics, Inc., 5770 Decatur Boulevard Suite A, Indianapolis, Indiana 46241, United States
| | - John Turek
- Purdue University, Department of Basic Medical Sciences, West Lafayette, 625 Harrison Street, Indiana 47907, United States
| | - Daniela Matei
- Northwestern University School of Medicine, 303 East SuperiorChicago, Illinois 60611, United States
| | - David D. Nolte
- Purdue University, Department of Physics, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
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9
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Taylor E, Yeung I, Keller H, Wouters BG, Milosevic M, Hedley DW, Jaffray DA. Quantifying hypoxia in human cancers using static PET imaging. Phys Med Biol 2016; 61:7957-7974. [PMID: 27779123 DOI: 10.1088/0031-9155/61/22/7957] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Compared to FDG, the signal of 18F-labelled hypoxia-sensitive tracers in tumours is low. This means that in addition to the presence of hypoxic cells, transport properties contribute significantly to the uptake signal in static PET images. This sensitivity to transport must be minimized in order for static PET to provide a reliable standard for hypoxia quantification. A dynamic compartmental model based on a reaction-diffusion formalism was developed to interpret tracer pharmacokinetics and applied to static images of FAZA in twenty patients with pancreatic cancer. We use our model to identify tumour properties-well-perfused without substantial necrosis or partitioning-for which static PET images can reliably quantify hypoxia. Normalizing the measured activity in a tumour voxel by the value in blood leads to a reduction in the sensitivity to variations in 'inter-corporal' transport properties-blood volume and clearance rate-as well as imaging study protocols. Normalization thus enhances the correlation between static PET images and the FAZA binding rate K 3, a quantity which quantifies hypoxia in a biologically significant way. The ratio of FAZA uptake in spinal muscle and blood can vary substantially across patients due to long muscle equilibration times. Normalized static PET images of hypoxia-sensitive tracers can reliably quantify hypoxia for homogeneously well-perfused tumours with minimal tissue partitioning. The ideal normalizing reference tissue is blood, either drawn from the patient before PET scanning or imaged using PET. If blood is not available, uniform, homogeneously well-perfused muscle can be used. For tumours that are not homogeneously well-perfused or for which partitioning is significant, only an analysis of dynamic PET scans can reliably quantify hypoxia.
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Affiliation(s)
- Edward Taylor
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada. Techna Institute, University Health Network, Toronto, Canada
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10
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Wack LJ, Mönnich D, Yaromina A, Zips D, Baumann M, Thorwarth D. Correlation of FMISO simulations with pimonidazole-stained tumor xenografts: A question of O2 consumption? Med Phys 2016; 43:4113. [PMID: 27370131 DOI: 10.1118/1.4951728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To compare a dedicated simulation model for hypoxia PET against tumor microsections stained for different parameters of the tumor microenvironment. The model can readily be adapted to a variety of conditions, such as different human head and neck squamous cell carcinoma (HNSCC) xenograft tumors. METHODS Nine different HNSCC tumor models were transplanted subcutaneously into nude mice. Tumors were excised and immunoflourescently labeled with pimonidazole, Hoechst 33342, and CD31, providing information on hypoxia, perfusion, and vessel distribution, respectively. Hoechst and CD31 images were used to generate maps of perfused blood vessels on which tissue oxygenation and the accumulation of the hypoxia tracer FMISO were mathematically simulated. The model includes a Michaelis-Menten relation to describe the oxygen consumption inside tissue. The maximum oxygen consumption rate M0 was chosen as the parameter for a tumor-specific optimization as it strongly influences tracer distribution. M0 was optimized on each tumor slice to reach optimum correlations between FMISO concentration 4 h postinjection and pimonidazole staining intensity. RESULTS After optimization, high pixel-based correlations up to R(2) = 0.85 were found for individual tissue sections. Experimental pimonidazole images and FMISO simulations showed good visual agreement, confirming the validity of the approach. Median correlations per tumor model varied significantly (p < 0.05), with R(2) ranging from 0.20 to 0.54. The optimum maximum oxygen consumption rate M0 differed significantly (p < 0.05) between tumor models, ranging from 2.4 to 5.2 mm Hg/s. CONCLUSIONS It is feasible to simulate FMISO distributions that match the pimonidazole retention patterns observed in vivo. Good agreement was obtained for multiple tumor models by optimizing the oxygen consumption rate, M0, whose optimum value differed significantly between tumor models.
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Affiliation(s)
- L J Wack
- Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, Tübingen 72076, Germany
| | - D Mönnich
- Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, Tübingen 72076, Germany; German Cancer Consortium (DKTK), Tübingen 72076, Germany; and German Cancer Research Center (DKFZ), Heidelberg 69121, Germany
| | - A Yaromina
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden 01309, Germany and Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht 6229 ET, The Netherlands
| | - D Zips
- German Cancer Consortium (DKTK), Tübingen 72076, Germany; German Cancer Research Center (DKFZ), Heidelberg 69121, Germany and Department of Radiation Oncology, University Hospital Tübingen, Tübingen 72076, Germany
| | - M Baumann
- German Cancer Consortium (DKTK), Dresden 01307, Germany; German Cancer Research Center (DKFZ), Heidelberg 69121, Germany; OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden 01309, Germany; Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden 01307, Germany; and Institute of Radiooncology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
| | - D Thorwarth
- Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, Tübingen 72076, Germany
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11
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Sjögren E, Eriksson J, Vedin C, Breitholtz K, Hilgendorf C. Excised segments of rat small intestine in Ussing chamber studies: A comparison of native and stripped tissue viability and permeability to drugs. Int J Pharm 2016; 505:361-8. [PMID: 27073083 DOI: 10.1016/j.ijpharm.2016.03.063] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/07/2016] [Accepted: 03/30/2016] [Indexed: 11/18/2022]
Abstract
Excised rat intestinal tissue mounted in an Ussing chamber can be used for intestinal permeability assessments in drug development. The outer layer of the intestine, the serosa and part of the muscle layer, is traditionally removed since it is considered a barrier to the diffusion of nutrients and oxygen as well as to that of pharmaceutical substances. However, the procedure for removing the serosal-muscle layer, i.e. stripping, is a technically challenging process in the pre-experimental preparation of the tissue which may result in tissue damage and reduced viability of the segment. In this study, the viability of stripped and native (non-stripped) rat small intestine tissue segments mounted in Ussing chambers was monitored and the apparent permeability of the tissue to a set of test compounds across both tissue preparations was determined. Electrical measurements, in particular the potential difference (PD) across the intestinal membrane, were used to evaluate the viability. In this study, there were no differences in initial PD (health status of the tissue) or PD over time (viability throughout the experiment) between native and stripped rat jejunum segments. Overall, there were also no significant differences in permeability between stripped and native rat intestinal tissue for the compounds in this study. Based on these results, we propose that stripping can be excluded from the preparation procedures for rat jejunal tissue for permeability studies when using the Ussing chamber technique.
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Affiliation(s)
- Erik Sjögren
- Department of Pharmacy, Uppsala University, Uppsala 75233, Sweden.
| | - Johanna Eriksson
- Department of Pharmacy, Uppsala University, Uppsala 75233, Sweden
| | - Charlotta Vedin
- DSM, Safety and ADME Translational Sciences, AstraZeneca Innovative Medicines and Early Development, Mölndal 43183, Sweden
| | - Katarina Breitholtz
- DSM, Safety and ADME Translational Sciences, AstraZeneca Innovative Medicines and Early Development, Mölndal 43183, Sweden
| | - Constanze Hilgendorf
- DSM, Safety and ADME Translational Sciences, AstraZeneca Innovative Medicines and Early Development, Mölndal 43183, Sweden
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12
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Efficient Protocol for the Identification of Hypoxic Cell Radiosensitisers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 899:269-90. [DOI: 10.1007/978-3-319-26666-4_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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13
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Wack LJ, Mönnich D, van Elmpt W, Zegers CML, Troost EGC, Zips D, Thorwarth D. Comparison of [18F]-FMISO, [18F]-FAZA and [18F]-HX4 for PET imaging of hypoxia--a simulation study. Acta Oncol 2015. [PMID: 26203928 DOI: 10.3109/0284186x.2015.1067721] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND To investigate the effect of hypoxia tracer properties on positron emission tomography (PET) image quality for three tracers [18F]-fluoromisonidazole (FMISO), [18F]-fluoroazomycinarabinoside (FAZA) and [18F]-flortanidazole (HX4), using mathematical simulations based on microscopic tumor tissue sections. MATERIAL AND METHODS Oxygen distribution and tracer binding was mathematically simulated on immunohistochemically stained cross-sections of tumor xenografts. Tracer diffusion properties were determined based on available literature. Blood activity and clearance over a four-hour period post-injection (p.i.) were derived from clinical dynamic PET scans of patients suffering from head and neck or bronchial cancer. Simulations were performed both for average patient blood activities and for individual patients, and image contrast between normoxic and hypoxic tissue areas was determined over this four-hour period p.i. RESULTS On average, HX4 showed a six-fold higher clearance than FMISO and an almost three-fold higher clearance than FAZA based on the clinical PET data. The absolute variation in clearance was significantly higher for HX4 than for FMISO (standard deviations of 5.75 *10-5 s-1 vs. 1.55 *10-5 s-1). The absolute tracer activity in these scans at four hours p.i. was highest for FMISO and lowest for HX4. Simulated contrast at four hours p.i. was highest for HX4 (2.39), while FMISO and FAZA were comparable (1.67 and 1.75, respectively). Variations in contrast of 7-11% were observed for each tracer depending on the vascularization patterns of the chosen tissue. Higher variations in clearance for HX4 resulted in an increased inter-patient variance in simulated contrast at four hours p.i. CONCLUSIONS In line with recent experimental and clinical data, the results suggest that HX4 is a promising new tracer that provides high image contrast four hours p.i., though inter-patient variance can be very high. Nevertheless, the widely used tracer FMISO provides a robust and reproducible signal four hours p.i., but with a lower contrast. The simulations revealed tracer clearance to be the key factor in determining image contrast.
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Affiliation(s)
- Linda J Wack
- a Section for Biomedical Physics, Department of Radiation Oncology , University Hospital Tübingen , Tübingen , Germany
| | - David Mönnich
- a Section for Biomedical Physics, Department of Radiation Oncology , University Hospital Tübingen , Tübingen , Germany
| | - Wouter van Elmpt
- b Department of Radiation Oncology (MAASTRO) , GROW - School for Oncology and Developmental Biology , Maastricht , The Netherlands
| | - Catharina M L Zegers
- b Department of Radiation Oncology (MAASTRO) , GROW - School for Oncology and Developmental Biology , Maastricht , The Netherlands
| | - Esther G C Troost
- b Department of Radiation Oncology (MAASTRO) , GROW - School for Oncology and Developmental Biology , Maastricht , The Netherlands
- c Helmholtz-Zentrum Dresden-Rossendorf , Dresden , Germany
| | - Daniel Zips
- d Department of Radiation Oncology , University Hospital Tübingen , Tübingen , Germany
| | - Daniela Thorwarth
- a Section for Biomedical Physics, Department of Radiation Oncology , University Hospital Tübingen , Tübingen , Germany
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14
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Linderman JJ, Cilfone NA, Pienaar E, Gong C, Kirschner DE. A multi-scale approach to designing therapeutics for tuberculosis. Integr Biol (Camb) 2015; 7:591-609. [PMID: 25924949 DOI: 10.1039/c4ib00295d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Approximately one third of the world's population is infected with Mycobacterium tuberculosis. Limited information about how the immune system fights M. tuberculosis and what constitutes protection from the bacteria impact our ability to develop effective therapies for tuberculosis. We present an in vivo systems biology approach that integrates data from multiple model systems and over multiple length and time scales into a comprehensive multi-scale and multi-compartment view of the in vivo immune response to M. tuberculosis. We describe computational models that can be used to study (a) immunomodulation with the cytokines tumor necrosis factor and interleukin 10, (b) oral and inhaled antibiotics, and
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Affiliation(s)
- Jennifer J Linderman
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
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15
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Pienaar E, Cilfone NA, Lin PL, Dartois V, Mattila JT, Butler JR, Flynn JL, Kirschner DE, Linderman JJ. A computational tool integrating host immunity with antibiotic dynamics to study tuberculosis treatment. J Theor Biol 2014; 367:166-179. [PMID: 25497475 DOI: 10.1016/j.jtbi.2014.11.021] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/17/2014] [Accepted: 11/20/2014] [Indexed: 12/31/2022]
Abstract
While active tuberculosis (TB) is a treatable disease, many complex factors prevent its global elimination. Part of the difficulty in developing optimal therapies is the large design space of antibiotic doses, regimens and combinations. Computational models that capture the spatial and temporal dynamics of antibiotics at the site of infection can aid in reducing the design space of costly and time-consuming animal pre-clinical and human clinical trials. The site of infection in TB is the granuloma, a collection of immune cells and bacteria that form in the lung, and new data suggest that penetration of drugs throughout granulomas is problematic. Here we integrate our computational model of granuloma formation and function with models for plasma pharmacokinetics, lung tissue pharmacokinetics and pharmacodynamics for two first line anti-TB antibiotics. The integrated model is calibrated to animal data. We make four predictions. First, antibiotics are frequently below effective concentrations inside granulomas, leading to bacterial growth between doses and contributing to the long treatment periods required for TB. Second, antibiotic concentration gradients form within granulomas, with lower concentrations toward their centers. Third, during antibiotic treatment, bacterial subpopulations are similar for INH and RIF treatment: mostly intracellular with extracellular bacteria located in areas non-permissive for replication (hypoxic areas), presenting a slowly increasing target population over time. Finally, we find that on an individual granuloma basis, pre-treatment infection severity (including bacterial burden, host cell activation and host cell death) is predictive of treatment outcome.
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Affiliation(s)
- Elsje Pienaar
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA; Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Nicholas A Cilfone
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Philana Ling Lin
- Department of Pediatrics, Children׳s Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Véronique Dartois
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Joshua T Mattila
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - J Russell Butler
- Department of Health and Biomedical Sciences, Adventist University of Health Sciences, Orlando, FL, USA
| | - JoAnne L Flynn
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Denise E Kirschner
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA.
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16
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Kuiper C, Vissers MCM, Hicks KO. Pharmacokinetic modeling of ascorbate diffusion through normal and tumor tissue. Free Radic Biol Med 2014; 77:340-52. [PMID: 25277418 DOI: 10.1016/j.freeradbiomed.2014.09.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/12/2014] [Accepted: 09/19/2014] [Indexed: 01/21/2023]
Abstract
Ascorbate is delivered to cells via the vasculature, but its ability to penetrate into tissues remote from blood vessels is unknown. This is particularly relevant to solid tumors, which often contain regions with dysfunctional vasculature, with impaired oxygen and nutrient delivery, resulting in upregulation of the hypoxic response and also the likely depletion of essential plasma-derived biomolecules, such as ascorbate. In this study, we have utilized a well-established multicell-layered, three-dimensional pharmacokinetic model to measure ascorbate diffusion and transport parameters through dense tissue in vitro. Ascorbate was found to penetrate the tissue at a slightly lower rate than mannitol and to travel via the paracellular route. Uptake parameters into the cells were also determined. These data were fitted to the diffusion model, and simulations of ascorbate pharmacokinetics in normal tissue and in hypoxic tumor tissue were performed with varying input concentrations, ranging from normal dietary plasma levels (10-100 μM) to pharmacological levels (>1 mM) as seen with intravenous infusion. The data and simulations demonstrate heterogeneous distribution of ascorbate in tumor tissue at physiological blood levels and provide insight into the range of plasma ascorbate concentrations and exposure times needed to saturate all regions of a tumor. The predictions suggest that supraphysiological plasma ascorbate concentrations (>100 μM) are required to achieve effective delivery of ascorbate to poorly vascularized tumor tissue.
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Affiliation(s)
- Caroline Kuiper
- Centre for Free Radical Research, Pathology Department, University of Otago at Christchurch, Christchurch, New Zealand.
| | - Margreet C M Vissers
- Centre for Free Radical Research, Pathology Department, University of Otago at Christchurch, Christchurch, New Zealand
| | - Kevin O Hicks
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
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17
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Novel nitroimidazole alkylsulfonamides as hypoxic cell radiosensitisers. Bioorg Med Chem 2014; 22:2123-32. [PMID: 24650701 DOI: 10.1016/j.bmc.2014.02.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 02/07/2014] [Accepted: 02/18/2014] [Indexed: 12/31/2022]
Abstract
A novel class of nitroimidazole alkylsulfonamides have been prepared and evaluated as hypoxia-selective cytotoxins and radiosensitisers. The sulfonamide side chain markedly influences the physicochemical properties of the analogues: lowering aqueous solubility and raising the electron affinity of the nitroimidazole group. The addition of hydroxyl or basic amine groups increased aqueous solubility, with charged amine groups contributing to increased electron affinity. The analogues covered the range of electron affinity for effective radiosensitisation with one-electron reduction potentials ranging from -503 to -342mV. Cytotoxicity under normoxia or anoxia against a panel of human tumour cell lines was determined using a proliferation assay. 2-Nitroimidazole sulfonamides displayed significant hypoxia-selective cytotoxicity (6 to 64-fold), while 4- and 5-nitroimidazole analogues did not display hypoxia-selective cytotoxicity. All analogues sensitised anoxic HCT-116 human colorectal cells to radiation at non-toxic concentrations. 2-Nitroimidazole analogues provided modest sensitisation due to the relatively low concentrations used while several 5-nitroimidazole analogues provided equivalent sensitisation to misonidazole and etanidazole at similar molar concentrations.
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18
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Hypoxia-Directed Drug Strategies to Target the Tumor Microenvironment. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 772:111-45. [DOI: 10.1007/978-1-4614-5915-6_6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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19
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Hunt MA, Li D, Hay MP, Currie MJ, Robinson BA, Patterson AV, Dachs GU. Characterisation of enzyme prodrug gene therapy combinations in coated spheroids and vascular networks in vitro. J Gene Med 2012; 14:62-74. [DOI: 10.1002/jgm.1635] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Michelle A. Hunt
- Angiogenesis and Cancer Research Group, Department of Pathology; University of Otago; Christchurch; New Zealand
| | - Dan Li
- Auckland Cancer Society Research Centre; University of Auckland; Auckland; New Zealand
| | - Michael P. Hay
- Auckland Cancer Society Research Centre; University of Auckland; Auckland; New Zealand
| | - Margaret J. Currie
- Angiogenesis and Cancer Research Group, Department of Pathology; University of Otago; Christchurch; New Zealand
| | - Bridget A. Robinson
- Angiogenesis and Cancer Research Group, Department of Pathology; University of Otago; Christchurch; New Zealand
| | - Adam V. Patterson
- Auckland Cancer Society Research Centre; University of Auckland; Auckland; New Zealand
| | - Gabi U. Dachs
- Angiogenesis and Cancer Research Group, Department of Pathology; University of Otago; Christchurch; New Zealand
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20
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Abstract
Recent advances in genome inspired target discovery, small molecule screens, development of biological and nanotechnology have led to the introduction of a myriad of new differently sized agents into the clinic. The differences in small and large molecule delivery are becoming increasingly important in combination therapies as well as the use of drugs that modify the physiology of tumors such as anti-angiogenic treatment. The complexity of targeting has led to the development of mathematical models to facilitate understanding, but unfortunately, these studies are often only applicable to a particular molecule, making pharmacokinetic comparisons difficult. Here we develop and describe a framework for categorizing primary pharmacokinetics of drugs in tumors. For modeling purposes, we define drugs not by their mechanism of action but rather their rate-limiting step of delivery. Our simulations account for variations in perfusion, vascularization, interstitial transport, and non-linear local binding and metabolism. Based on a comparison of the fundamental rates determining uptake, drugs were classified into four categories depending on whether uptake is limited by blood flow, extravasation, interstitial diffusion, or local binding and metabolism. Simulations comparing small molecule versus macromolecular drugs show a sharp difference in distribution, which has implications for multi-drug therapies. The tissue-level distribution differs widely in tumors for small molecules versus macromolecular biologic drugs, and this should be considered in the design of agents and treatments. An example using antibodies in mouse xenografts illustrates the different in vivo behavior. This type of transport analysis can be used to aid in model development, experimental data analysis, and imaging and therapeutic agent design.
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Abstract
Hypoxia is a feature of most tumours, albeit with variable incidence and severity within a given patient population. It is a negative prognostic and predictive factor owing to its multiple contributions to chemoresistance, radioresistance, angiogenesis, vasculogenesis, invasiveness, metastasis, resistance to cell death, altered metabolism and genomic instability. Given its central role in tumour progression and resistance to therapy, tumour hypoxia might well be considered the best validated target that has yet to be exploited in oncology. However, despite an explosion of information on hypoxia, there are still major questions to be addressed if the long-standing goal of exploiting tumour hypoxia is to be realized. Here, we review the two main approaches, namely bioreductive prodrugs and inhibitors of molecular targets upon which hypoxic cell survival depends. We address the particular challenges and opportunities these overlapping strategies present, and discuss the central importance of emerging diagnostic tools for patient stratification in targeting hypoxia.
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Affiliation(s)
- William R Wilson
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand.
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Hicks KO, Siim BG, Jaiswal JK, Pruijn FB, Fraser AM, Patel R, Hogg A, Liyanage HDS, Dorie MJ, Brown JM, Denny WA, Hay MP, Wilson WR. Pharmacokinetic/pharmacodynamic modeling identifies SN30000 and SN29751 as tirapazamine analogues with improved tissue penetration and hypoxic cell killing in tumors. Clin Cancer Res 2010; 16:4946-57. [PMID: 20732963 DOI: 10.1158/1078-0432.ccr-10-1439] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Tirapazamine (TPZ) has attractive features for targeting hypoxic cells in tumors but has limited clinical activity, in part because of poor extravascular penetration. Here, we identify improved TPZ analogues by using a spatially resolved pharmacokinetic/pharmacodynamic (SR-PKPD) model that considers tissue penetration explicitly during lead optimization. EXPERIMENTAL DESIGN The SR-PKPD model was used to guide the progression of 281 TPZ analogues through a hierarchical screen. For compounds exceeding hypoxic selectivity thresholds in single-cell cultures, SR-PKPD model parameters (kinetics of bioreductive metabolism, clonogenic cell killing potency, diffusion coefficients in multicellular layers, and plasma pharmacokinetics at well tolerated doses in mice) were measured to prioritize testing in xenograft models in combination with radiation. RESULTS SR-PKPD-guided lead optimization identified SN29751 and SN30000 as the most promising hypoxic cytotoxins from two different structural subseries. Both were reduced to the corresponding 1-oxide selectively under hypoxia by HT29 cells, with an oxygen dependence quantitatively similar to that of TPZ. SN30000, in particular, showed higher hypoxic potency and selectivity than TPZ in tumor cell cultures and faster diffusion through HT29 and SiHa multicellular layers. Both compounds also provided superior plasma PK in mice and rats at equivalent toxicity. In agreement with SR-PKPD predictions, both were more active than TPZ with single dose or fractionated radiation against multiple human tumor xenografts. CONCLUSIONS SN30000 and SN29751 are improved TPZ analogues with potential for targeting tumor hypoxia in humans. Novel SR-PKPD modeling approaches can be used for lead optimization during anticancer drug development.
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Affiliation(s)
- Kevin O Hicks
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
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23
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Denny WA. Hypoxia-activated prodrugs in cancer therapy: progress to the clinic. Future Oncol 2010; 6:419-28. [PMID: 20222798 DOI: 10.2217/fon.10.1] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The hypoxic cells common in solid tumors (because of their inefficient blood supply) limit the effectiveness of radiotherapy and many cytotoxic drugs. Nontoxic prodrugs that generate active species in hypoxic tissue by selective bioreduction have long been explored, and the first examples, representing a variety of different chemistries, have now reached advanced clinical trials. In the process, a great deal has been learnt about the properties that such drugs require to be successful, notably, efficient extravascular diffusion, appropriate reduction chemistry and kinetics, and an effective biological profile of the activated species, including a good bystander effect. The critical importance of prodrug diffusion and techniques to quantify this have assisted the development of models to predict the killing of tumor cells, which promises to help accelerate new drug evaluation. A cell cycle-independent mechanism of killing by the released cytotoxin is also a potential advantage, although it is likely that much of the killing will be when out-of-cycle hypoxic cells reoxygenate and resume division.
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Affiliation(s)
- William A Denny
- Auckland Cancer Society Research Centre, The University of Auckland, New Zealand.
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Hay MP, Hicks KO, Pchalek K, Lee HH, Blaser A, Pruijn FB, Anderson RF, Shinde SS, Wilson WR, Denny WA. Tricyclic [1,2,4]triazine 1,4-dioxides as hypoxia selective cytotoxins. J Med Chem 2008; 51:6853-65. [PMID: 18847185 DOI: 10.1021/jm800967h] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A series of novel tricyclic triazine-di- N-oxides (TTOs) related to tirapazamine have been designed and prepared. A wide range of structural arrangements with cycloalkyl, oxygen-, and nitrogen-containing saturated rings fused to the triazine core, coupled with various side chains linked to either hemisphere, resulted in TTO analogues that displayed hypoxia-selective cytotoxicity in vitro. Optimal rates of hypoxic metabolism and tissue diffusion coefficients were achieved with fused cycloalkyl rings in combination with both the 3-aminoalkyl or 3-alkyl substituents linked to weakly basic soluble amines. The selection was further refined using pharmacokinetic/pharmacodynamic model predictions of the in vivo hypoxic potency (AUC req) and selectivity (HCD) with 12 TTO analogues predicted to be active in vivo, subject to the achievement of adequate plasma pharmacokinetics.
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Affiliation(s)
- Michael P Hay
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
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Abstract
The physiological differences between solid tumours and the healthy tissues and organs of the body are both an impediment to effective treatment and a potential basis for targeting strategies. In the present review, we outline the physiological features that distinguish tumours including hypoxia, acidity, and inhibited transport and describe the strategies being employed to exploit these differences in order to generate more selective and less toxic anticancer agents.
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