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Wadsworth BJ, Lee CM, Bennewith KL. Transiently hypoxic tumour cell turnover and radiation sensitivity in human tumour xenografts. Br J Cancer 2022; 126:1616-1626. [PMID: 35031765 PMCID: PMC9130130 DOI: 10.1038/s41416-021-01691-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/24/2021] [Accepted: 12/23/2021] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Solid tumour perfusion can be unstable, creating transiently hypoxic cells that can contribute to radiation resistance. We investigated the in vivo lifetime of transiently hypoxic tumour cells and chronically hypoxic tumour cells during tumour growth and following irradiation. METHODS Hypoxic cells in SiHa and WiDr human tumour xenografts were labelled using pimonidazole and EF5, and turnover was quantified as the loss of labelled cells over time. The perfusion-modifying drug pentoxifylline was used to reoxygenate transiently hypoxic cells prior to hypoxia marker administration or irradiation. RESULTS Chronically hypoxic cells constantly turnover in SiHa and WiDr tumours, with half-lives ranging from 42-82 h and significant numbers surviving >96 h. Transiently hypoxic cells constitute 26% of the total hypoxic cells in WiDr tumours. These transiently hypoxic cells survive at least 24 h, but then rapidly turnover with a half-life of 34 h and are undetectable 72 h after labelling. Transiently hypoxic cells are radiation-resistant, although vascular dysfunction induced by 10 Gy of ionising radiation preferentially kills transiently hypoxic cells. CONCLUSIONS Transiently hypoxic tumour cells survive up to 72 h in WiDr tumours and are radiation-resistant, although transiently hypoxic cells are sensitive to vascular dysfunction induced by high doses of ionising radiation.
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Affiliation(s)
- Brennan J. Wadsworth
- Integrative Oncology, BC Cancer, Vancouver, BC Canada ,grid.17091.3e0000 0001 2288 9830Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC Canada
| | - Che-Min Lee
- Integrative Oncology, BC Cancer, Vancouver, BC Canada ,grid.17091.3e0000 0001 2288 9830Interdisciplinary Oncology Program, University of British Columbia, Vancouver, BC Canada
| | - Kevin L. Bennewith
- Integrative Oncology, BC Cancer, Vancouver, BC Canada ,grid.17091.3e0000 0001 2288 9830Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC Canada ,grid.17091.3e0000 0001 2288 9830Interdisciplinary Oncology Program, University of British Columbia, Vancouver, BC Canada
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2
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Grist SM, Nasseri SS, Laplatine L, Schmok JC, Yao D, Hua J, Chrostowski L, Cheung KC. Long-term monitoring in a microfluidic system to study tumour spheroid response to chronic and cycling hypoxia. Sci Rep 2019; 9:17782. [PMID: 31780697 PMCID: PMC6883080 DOI: 10.1038/s41598-019-54001-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 11/06/2019] [Indexed: 12/18/2022] Open
Abstract
We demonstrate the application of a microfluidic platform combining spatiotemporal oxygen control and long-term microscopy monitoring to observe tumour spheroid response to hypoxia. The platform is capable of recreating physiologically-relevant low and cycling oxygen levels not attainable in traditional cell culture environments, while image-based monitoring visualizes cell response to these physiologically-relevant conditions. Monitoring spheroid cultures during hypoxic exposure allows us to observe, for the first time, that spheroids swell and shrink in response to time-varying oxygen profiles switching between 0% and 10% O2; this swelling-shrinkage behaviour appears to be driven by swelling of individual cells within the spheroids. We also apply the system to monitoring tumour models during anticancer treatment under varying oxygen conditions. We observe higher uptake of the anticancer agent doxorubicin under a cycling hypoxia profile than under either chronic hypoxia or in vitro normoxia, and the two-photon microscopy monitoring facilitated by our system also allows us to observe heterogeneity in doxorubicin uptake within spheroids at the single-cell level. Combining optical sectioning microscopy with precise spatiotemporal oxygen control and 3D culture opens the door for a wide range of future studies on microenvironmental mechanisms driving cancer progression and resistance to anticancer therapy. These types of studies could facilitate future improvements in cancer diagnostics and treatment.
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Affiliation(s)
- Samantha M Grist
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, Canada.
| | - S Soroush Nasseri
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, Canada
| | - Loïc Laplatine
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, Canada
| | - Jonathan C Schmok
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, Canada
| | - Dickson Yao
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, Canada
| | - Jessica Hua
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, Canada
| | - Lukas Chrostowski
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, Canada
| | - Karen C Cheung
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, Canada.
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3
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Challapalli A, Carroll L, Aboagye EO. Molecular mechanisms of hypoxia in cancer. Clin Transl Imaging 2017; 5:225-253. [PMID: 28596947 PMCID: PMC5437135 DOI: 10.1007/s40336-017-0231-1] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 04/21/2017] [Indexed: 02/07/2023]
Abstract
PURPOSE Hypoxia is a condition of insufficient oxygen to support metabolism which occurs when the vascular supply is interrupted, or when a tumour outgrows its vascular supply. It is a negative prognostic factor due to its association with an aggressive tumour phenotype and therapeutic resistance. This review provides an overview of hypoxia imaging with Positron emission tomography (PET), with an emphasis on the biological relevance, mechanism of action, highlighting advantages, and limitations of the currently available hypoxia radiotracers. METHODS A comprehensive PubMed literature search was performed, identifying articles relating to biological significance and measurement of hypoxia, MRI methods, and PET imaging of hypoxia in preclinical and clinical settings, up to December 2016. RESULTS A variety of approaches have been explored over the years for detecting and monitoring changes in tumour hypoxia, including regional measurements with oxygen electrodes placed under CT guidance, MRI methods that measure either oxygenation or lactate production consequent to hypoxia, different nuclear medicine approaches that utilise imaging agents the accumulation of which is inversely related to oxygen tension, and optical methods. The advantages and disadvantages of these approaches are reviewed, along with individual strategies for validating different imaging methods. PET is the preferred method for imaging tumour hypoxia due to its high specificity and sensitivity to probe physiological processes in vivo, as well as the ability to provide information about intracellular oxygenation levels. CONCLUSION Even though hypoxia could have significant prognostic and predictive value in the clinic, the best method for hypoxia assessment has in our opinion not been realised.
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Affiliation(s)
- Amarnath Challapalli
- Department of Clinical Oncology, Bristol Cancer Institute, Horfield Road, Bristol, United Kingdom
| | - Laurence Carroll
- Department of Surgery and Cancer, Imperial College, GN1, Commonwealth Building, Hammersmith Hospital, Du Cane Road, London, W120NN United Kingdom
| | - Eric O. Aboagye
- Department of Surgery and Cancer, Imperial College, GN1, Commonwealth Building, Hammersmith Hospital, Du Cane Road, London, W120NN United Kingdom
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4
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Abstract
There is an important and strong, but complex influence of the tumor microenvironment on tumor cells' phenotype, aggressiveness, and treatment sensitivity. One of the most frequent and best-studied aspects of the tumor microenvironment is hypoxia. Low oxygen tension often occurs in tumor cells by several mechanisms, for example, poor angiogenesis and increased oxygen consumption. Hypoxia is a heterogeneous concept with oxygen tensions ranging from <0.01% (anoxia) to 5%, and can be chronic, acute, or cycling, all with differential effects on tumor cells. Quantification of tumor hypoxia can be performed directly or indirectly, and with exogenous or endogenous markers. Tumor cells launch different intracellular signaling pathways to survive hypoxia, such as hypoxia-inducible factor 1-mediated gene expression, the unfolded protein response, and AKT-mammalian target of rapamycin signaling. These pathways induce aggressive, metastatic, and treatment-insensitive tumors and are considered potential targets for (additive) therapy. Hypoxia leads to important, yet currently not well-understood changes in microRNA expression, epigenetics, and metabolism. Further, treatment-insensitive tumors arise through hypoxia-induced Darwinian selection of apoptosis-deficient, p53-mutated tumor cells. In conclusion, hypoxia has profound and largely still poorly understood effects on tumor cells with a major effect on the tumor's biology.
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Affiliation(s)
- Paul N Span
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Johan Bussink
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands.
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5
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Gonçalves MR, Johnson SP, Ramasawmy R, Pedley RB, Lythgoe MF, Walker-Samuel S. Decomposition of spontaneous fluctuations in tumour oxygenation using BOLD MRI and independent component analysis. Br J Cancer 2015; 113:1168-77. [PMID: 26484634 PMCID: PMC4647875 DOI: 10.1038/bjc.2015.270] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/26/2015] [Accepted: 06/29/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Solid tumours can undergo cycles of hypoxia, followed by reoxygenation, which can have significant implications for the success of anticancer therapies. A need therefore exists to develop methods to aid its detection and to further characterise its biological basis. We present here a novel method for decomposing systemic and tumour-specific contributions to fluctuations in tumour deoxyhaemoglobin concentration, based on magnetic resonance imaging measurements. METHODS Fluctuations in deoxyhaemoglobin concentration in two tumour xenograft models of colorectal carcinoma were decomposed into distinct contributions using independent component analysis. These components were then correlated with systemic pulse oximetry measurements to assess the influence of systemic variations in blood oxygenation in tumours, compared with those that arise within the tumour itself (tumour-specific). Immunohistochemical staining was used to assess the physiological basis of each source of fluctuation. RESULTS Systemic fluctuations in blood oxygenation were found to contribute to cycling hypoxia in tumours, but tumour-specific fluctuations were also evident. Moreover, the size of the tumours was found to influence the degree of systemic, but not tumour-specific, oscillations. The degree of vessel maturation was related to the amplitude of tumour-specific, but not systemic, oscillations. CONCLUSIONS Our results provide further insights into the complexity of spontaneous fluctuations in tumour oxygenation and its relationship with tumour pathophysiology. These observations could be used to develop improved drug delivery strategies.
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Affiliation(s)
- Miguel R Gonçalves
- Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London WC1E 6DD, UK
| | - S Peter Johnson
- Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London WC1E 6DD, UK
- Cancer Institute, University College London, London WC1E 6DD, UK
| | - Rajiv Ramasawmy
- Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London WC1E 6DD, UK
| | - R Barbara Pedley
- Cancer Institute, University College London, London WC1E 6DD, UK
| | - Mark F Lythgoe
- Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London WC1E 6DD, UK
| | - Simon Walker-Samuel
- Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London WC1E 6DD, UK
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6
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Abstract
SIGNIFICANCE Most solid tumors contain regions of low oxygenation or hypoxia. Tumor hypoxia has been associated with a poor clinical outcome and plays a critical role in tumor radioresistance. RECENT ADVANCES Two main types of hypoxia exist in the tumor microenvironment: chronic and cycling hypoxia. Chronic hypoxia results from the limited diffusion distance of oxygen, and cycling hypoxia primarily results from the variation in microvessel red blood cell flux and temporary disturbances in perfusion. Chronic hypoxia may cause either tumor progression or regressive effects depending on the tumor model. However, there is a general trend toward the development of a more aggressive phenotype after cycling hypoxia. With advanced hypoxia imaging techniques, spatiotemporal characteristics of tumor hypoxia and the changes to the tumor microenvironment can be analyzed. CRITICAL ISSUES In this review, we focus on the biological and clinical consequences of chronic and cycling hypoxia on radiation treatment. We also discuss the advanced non-invasive imaging techniques that have been developed to detect and monitor tumor hypoxia in preclinical and clinical studies. FUTURE DIRECTIONS A better understanding of the mechanisms of tumor hypoxia with non-invasive imaging will provide a basis for improved radiation therapeutic practices.
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Affiliation(s)
- Chen-Ting Lee
- 1 Department of Radiation Oncology, Duke University Medical Center , Durham, North Carolina
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7
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Thurber GM, Yang KS, Reiner T, Kohler RH, Sorger P, Mitchison T, Weissleder R. Single-cell and subcellular pharmacokinetic imaging allows insight into drug action in vivo. Nat Commun 2013; 4:1504. [PMID: 23422672 DOI: 10.1038/ncomms2506] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 01/16/2013] [Indexed: 02/07/2023] Open
Abstract
Pharmacokinetic analysis at the organ level provides insight into how drugs distribute throughout the body, but cannot explain how drugs work at the cellular level. Here we demonstrate in vivo single-cell pharmacokinetic imaging of PARP-1 inhibitors and model drug behaviour under varying conditions. We visualize intracellular kinetics of the PARP-1 inhibitor distribution in real time, showing that PARP-1 inhibitors reach their cellular target compartment, the nucleus, within minutes in vivo both in cancer and normal cells in various cancer models. We also use these data to validate predictive finite element modelling. Our theoretical and experimental data indicate that tumour cells are exposed to sufficiently high PARP-1 inhibitor concentrations in vivo and suggest that drug inefficiency is likely related to proteomic heterogeneity or insensitivity of cancer cells to DNA-repair inhibition. This suggests that single-cell pharmacokinetic imaging and derived modelling improve our understanding of drug action at single-cell resolution in vivo.
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Affiliation(s)
- Greg M Thurber
- Center for Systems Biology, Massachusetts General Hospital, 185 Cambridge Street, CPZN 5206, Boston, Massachusetts 02114, USA
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8
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Bayer C, Vaupel P. Acute versus chronic hypoxia in tumors: Controversial data concerning time frames and biological consequences. Strahlenther Onkol 2012; 188:616-27. [PMID: 22454045 DOI: 10.1007/s00066-012-0085-4] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 01/20/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Many tumors contain hypoxic regions. Hypoxia, in turn, is known to increase aggressiveness and to be associated with treatment resistance. The two most frequently described and investigated subtypes of tumor hypoxia are acute and chronic. These two subtypes can lead to completely different hypoxia-related responses within the tumor, which could have a direct effect on tumor development and response to treatment. In order to accurately assess the specific biological consequences, it is important to understand which time frames best define acute and chronic hypoxia. MATERIALS AND METHODS This article provides an overview of the kinetics of in vitro and in vivo acute and chronic tumor hypoxia. Special attention was paid to differentiate between methods to detect spontaneous in vivo hypoxia and to describe the biological effects of experimental in vitro and in vivo acute and chronic tumor hypoxia. RESULTS AND CONCLUSIONS There are large variations in reported spontaneous fluctuations in acute hypoxia that are dependent on the cell lines investigated and the detection method used. In addition to differing hypoxia levels, exposure times used to induce in vitro and in vivo experimental acute and chronic hypoxia range from 30 min to several weeks with no clear boundaries separating the two. Evaluation of the biological consequences of each hypoxia subtype revealed a general trend that acute hypoxia leads to a more aggressive phenotype. Importantly, more information on the occurrence of acute and chronic hypoxia in human tumors is needed to help our understanding of the clinical consequences.
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Affiliation(s)
- C Bayer
- Department of Radiotherapy and Radiation Oncology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany.
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9
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Kyle AH, Baker JH, Minchinton AI. Targeting Quiescent Tumor Cells via Oxygen and IGF-I Supplementation. Cancer Res 2011; 72:801-9. [DOI: 10.1158/0008-5472.can-11-3059] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Cárdenas-Navia LI, Mace D, Richardson RA, Wilson DF, Shan S, Dewhirst MW. The pervasive presence of fluctuating oxygenation in tumors. Cancer Res 2008; 68:5812-9. [PMID: 18632635 DOI: 10.1158/0008-5472.can-07-6387] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tumor hypoxia is a persistent obstacle for traditional therapies in solid tumors. Strategies for mitigating the effects of hypoxic tumor cells have been developed under the assumption that chronically hypoxic tumor cells were the central cause of treatment resistance. In this study, we show that instabilities in tumor oxygenation are a prevalent characteristic of three tumor lines and previous characterization of tumor hypoxia as being primarily diffusion-limited does not accurately portray the tumor microenvironment. Phosphorescence lifetime imaging was used to measure fluctuations in vascular pO(2) in rat fibrosarcomas, 9L gliomas, and R3230 mammary adenocarcinomas grown in dorsal skin-fold window chambers (n = 6 for each tumor type) and imaged every 2.5 minutes for a duration of 60 to 90 minutes. O(2) delivery to tumors is constantly changing in all tumors, resulting in continuous reoxygenation events throughout the tumor. Vascular pO(2) maps show significant spatial heterogeneity at each time point, as well as between time points. The fluctuations in oxygenation occur with a common periodicity within and between tumors, suggesting a common mechanism, but have tumor type-dependent spatial patterns. The widespread presence of fluctuations in tumor oxygenation has broad ranging implications for tumor progression, stress response, and signal transduction, which are altered by oxygenation/reoxygenation events.
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11
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Dewhirst MW, Cao Y, Moeller B. Cycling hypoxia and free radicals regulate angiogenesis and radiotherapy response. Nat Rev Cancer 2008; 8:425-37. [PMID: 18500244 PMCID: PMC3943205 DOI: 10.1038/nrc2397] [Citation(s) in RCA: 756] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hypoxia and free radicals, such as reactive oxygen and nitrogen species, can alter the function and/or activity of the transcription factor hypoxia-inducible factor 1 (HIF1). Interplay between free radicals, hypoxia and HIF1 activity is complex and can influence the earliest stages of tumour development. The hypoxic environment of tumours is heterogeneous, both spatially and temporally, and can change in response to cytotoxic therapy. Free radicals created by hypoxia, hypoxia-reoxygenation cycling and immune cell infiltration after cytotoxic therapy strongly influence HIF1 activity. HIF1 can then promote endothelial and tumour cell survival. As discussed here, a constant theme emerges: inhibition of HIF1 activity will have therapeutic benefit.
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Affiliation(s)
- Mark W Dewhirst
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA
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12
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Cárdenas-Navia LI, Secomb TW, Dewhirst MW. Effects of fluctuating oxygenation on tirapazamine efficacy: Theoretical predictions. Int J Radiat Oncol Biol Phys 2007; 67:581-6. [PMID: 17236974 DOI: 10.1016/j.ijrobp.2006.10.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2006] [Revised: 10/04/2006] [Accepted: 10/04/2006] [Indexed: 11/23/2022]
Abstract
PURPOSE To examine the effects of fluctuating oxygen levels on the hypoxic cytotoxin tirapazamine (TPZ) using theoretical predictions. METHODS AND MATERIALS Tirapazamine's pharmacokinetic and pharmacodynamic oxygen dependence has previously been characterized in vitro. Here, a one-dimensional theoretical model was used to examine the effects of fluctuating hypoxia on metabolized TPZ concentration, assuming sinusoidally fluctuating oxygen levels. TPZ concentration is changing according to published experimental data. Simulations of experimentally observed time-courses of perivascular pO2 were also conducted. RESULTS The predicted pharmacodynamic effect of TPZ was increased with fluctuating (vs. constant) hypoxia at all frequencies (1-30 min period) and all amplitudes (1-15 mm Hg). Additionally, fluctuating oxygen resulted in more metabolized TPZ near the oxygen source as compared with the steady-state condition of the same overall average pO2. CONCLUSIONS Fluctuating pO2 reduced the concentration of metabolized TPZ at distances farther from the source, thereby limiting its ability to reach and kill the most hypoxic cells. These results suggest that the kinetics of fluctuating oxygenation should be taken into account when considering drug designs that involve oxygen-sensitive agents.
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Abstract
To be most effective anticancer drugs must penetrate tissue efficiently, reaching all the cancer cells that comprise the target population in a concentration sufficient to exert a therapeutic effect. Most research into the resistance of cancers to chemotherapy has concentrated on molecular mechanisms of resistance, whereas the role of limited drug distribution within tumours has been neglected. We summarize the evidence that indicates that the distribution of many anticancer drugs in tumour tissue is incomplete, and we suggest strategies that might be used either to improve drug penetration through tumour tissue or to select compounds based on their abilities to penetrate tissue, thereby increasing the therapeutic index.
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Affiliation(s)
- Andrew I Minchinton
- Department of Medical Biophysics, British Columbia Cancer Research Centre, Vancouver, Canada.
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14
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Martinive P, De Wever J, Bouzin C, Baudelet C, Sonveaux P, Grégoire V, Gallez B, Feron O. Reversal of temporal and spatial heterogeneities in tumor perfusion identifies the tumor vascular tone as a tunable variable to improve drug delivery. Mol Cancer Ther 2006; 5:1620-7. [PMID: 16818522 DOI: 10.1158/1535-7163.mct-05-0472] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Maturation of tumor vasculature involves the recruitment of pericytes that protect the endothelial tubes from a variety of stresses, including antiangiogenic drugs. Mural cells also provide mature tumor blood vessels with the ability to either relax or contract in response to substances present in the tumor microenvironment. The observed cyclic alterations in tumor blood flow and the associated deficit in chemotherapeutic drug delivery could in part arise from this vasomodulatory influence. To test this hypothesis, we focused on endothelin-1 (ET-1), which, besides its autocrine effects on tumor cell growth, is a powerful vasoconstrictor. We first document that an ET(A) receptor antagonist induced relaxation of microdissected tumor arterioles and selectively and quantitatively increased tumor blood flow in experimental tumor models. We then combined dye staining of functional vessels, fluorescent microsphere-based mapping, and magnetic resonance imaging to identify heterogeneities in tumor blood flow and to examine the reversibility of such phenomena. Data from all these techniques concurred to show that administration of an ET(A) receptor antagonist could reduce the extent of underperfused tumor areas, proving the key role of vessel tone variations in tumor blood flow heterogeneity. We also provide evidence that ET(A) antagonist administration could, despite an increase in tumor interstitial fluid pressure, improve access of cyclophosphamide to the tumor compartment and significantly influence tumor growth. In conclusion, tumor endogenous ET-1 production participates largely in the temporal and spatial variations in tumor blood flow. ET(A) antagonist administration may wipe out such heterogeneities, thus representing an adjuvant strategy that could improve the delivery of conventional chemotherapy to tumors.
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Affiliation(s)
- Philippe Martinive
- Unit of Pharmacology and Therapeutics, UCL Medical School, 53 Ave E. Mounier, B-1200 Brussels, Belgium
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15
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Huxham LA, Kyle AH, Baker JHE, McNicol KL, Minchinton AI. Tirapazamine causes vascular dysfunction in HCT-116 tumour xenografts. Radiother Oncol 2006; 78:138-45. [PMID: 16455148 DOI: 10.1016/j.radonc.2006.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 12/19/2005] [Accepted: 01/06/2006] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE Tirapazamine is a hypoxic cytotoxin currently undergoing Phase II/III clinical evaluation in combination with radiation and chemotherapeutics for the treatment of non-hematological cancers. Tissue penetration studies using multicellular models have suggested that tirapazamine exposure may be limited to cells close to blood vessels. However, animal studies show tirapazamine enhances the anti-tumour activity of radiation and chemotherapy and clinical studies with tirapazamine, so far, are promising. To investigate this apparent paradox we examined the microregional effects of tirapazamine in vivo by mapping drug effects with respect to the position of blood vessels in tumour cryosections. PATIENTS AND METHODS Tirapazamine was administered i.p. to mice bearing HCT-116 tumours, which were excised at various times after treatment. Images of multiple-stained cryosections were overlaid to provide microregional information on the relative position of proliferating cells, hypoxia, perfusion and vasculature. RESULTS We observed extensive and permanent vascular dysfunction in a large proportion of tumours from mice treated with tirapazamine. In the affected tumours, blood flow ceased in the centrally located tumour vessels, leaving a rim of functional vessels around the periphery of the tumour. This vascular dysfunction commenced within 24 h after tirapazamine administration and the areas affected appeared to be replaced by necrosis over the following 24-48 h. CONCLUSIONS Because the majority of hypoxic cells are located in the center of tumours we propose that the activity of tirapazamine in vivo may be related to its effects on tumour vasculature and that its activity against hypoxic cells located distal to functional blood vessels may not be as important as previously believed.
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Affiliation(s)
- Lynsey A Huxham
- Medical Biophysics Department, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
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16
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Kyle AH, Huxham LA, Chiam ASJ, Sim DH, Minchinton AI. Direct assessment of drug penetration into tissue using a novel application of three-dimensional cell culture. Cancer Res 2004; 64:6304-9. [PMID: 15342419 DOI: 10.1158/0008-5472.can-04-1099] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The failure of many anticancer drugs to control growth of solid cancers may stem in part from inadequate delivery to tumor regions distant from vasculature. Although the identification of new anticancer drug targets has led to the development of many new drug candidates, there is a lack of methodology for identifying drugs that adequately penetrate tumor tissue. We have developed a novel multilayered cell culture-based assay, which detects the penetration of anticancer drugs based on their effect within tissue. Drug exposures are made over 1 hour to one side of a disk of tissue approximately 150-microm thick, with the other side temporarily closed off, and penetration is then assessed 1-3 days later via bromodeoxyuridine-based detection of S-phase cells. Using this assay, the tissue distribution of a selection of anthracycline analogues was assessed. At clinically relevant exposures, none of the agents were able to affect cells on the far side of the culture at levels approaching that seen on the near (exposed) side. Doxorubicin and epirubicin exhibited approximately 10-fold decreases in the drug exposure seen by the cells on the far side relative to those on the near side of the cultures, whereas for daunorubicin and mitoxantrone, approximately 30-fold and >30-fold decreases were observed respectively. Results were consistent with the observed gradients in drug-derived fluorescence of doxorubicin, epirubicin, and daunorubicin. This model could be applied as a simple anticancer drug development screen to discover drugs that exhibit desirable penetration properties.
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Affiliation(s)
- Alastair H Kyle
- Department of Medical Biophysics, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
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17
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Kirkpatrick JP, Cárdenas-Navia LI, Dewhirst MW. Predicting the effect of temporal variations in PO2 on tumor radiosensitivity. Int J Radiat Oncol Biol Phys 2004; 59:822-33. [PMID: 15183486 DOI: 10.1016/j.ijrobp.2004.02.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2003] [Revised: 02/03/2004] [Accepted: 02/09/2004] [Indexed: 11/23/2022]
Abstract
PURPOSE Tumor hypoxia is associated with less effective radiation-mediated cell killing, increased metastatic potential, and poorer prognosis. Transient variations in hypoxia, with characteristic periodicity on the order of 1 to 10 min, have been observed in animal models. This article explores the effect of these temporal variations in PO(2) on the oxygen enhancement ratio, effective radiation dose to the tumor, and tumor control probability. METHODS AND MATERIALS PO(2) over a 50-60 min period was determined at multiple sites in rat fibrosarcomas, 9L gliomas, and R3230Ac mammary adenocarcinomas. Using a correlation derived from the data of Elkind et al. (1965), PO(2) data are converted into oxygen enhancement ratios (OERs.) A tumor is assumed to consist of 10(3)-10(4) independent oxygenation subvolumes, each with a randomly chosen starting point on the OER-time curve. The effect of temporal variations in OER is examined for three cases: conventionally fractionated external beam radiotherapy (EBRT), stereotactic radiosurgery (SRS) and intraoperative radiotherapy (IORT). The oxygen effective dose (OED) for a subvolume is calculated from the dose to that subvolume modified by the OER. In turn, the distribution of OED for a tumor is analyzed for each treatment case and representative tumor control probabilities (TCPs) calculated. RESULTS Oxygen enhancement ratio varied from 1 to 3 over the range of PO(2) measured in this study. Mean OER ranged from 1.6 to 2.6, and the variation in OER vs. time was greater with decreasing PO(2). In EBRT, the standard deviation in OED was small, <2%. In contrast, the standard deviation in OED was much higher for both SRS and IORT, typically ranging from 3 to 6%, with the greatest variation at the lowest PO(2)s. Compared with a tumor with equal mean OED and uniform PO(2), TCP was minimally poorer for either EBRT or well-oxygenated tumors. However, for both SRS and IORT, temporal variations in more hypoxic tumors can produce a significant decrease in TCP. CONCLUSION Temporal variations in tumor PO(2) can produce significant variations OER, particularly at low PO(2), resulting in decreased TCP for hypofractionated treatment regimens.
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Affiliation(s)
- J P Kirkpatrick
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
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18
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Greco O, Marples B, Joiner MC, Scott SD. How to overcome (and exploit) tumor hypoxia for targeted gene therapy. J Cell Physiol 2003; 197:312-25. [PMID: 14566961 DOI: 10.1002/jcp.10374] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Tumor hypoxia has long been recognized as a critical issue in oncology. Resistance of hypoxic areas has been shown to affect treatment outcome after radiation, chemotherapy, and surgery in a number of tumor sites. Two main strategies to overcome tumor hypoxia are to increase the delivery of oxygen (or oxygen-mimetic drugs), and exploiting this unique environmental condition of solid tumors for targeted therapy. The first strategy includes hyperbaric oxygen breathing, the administration of carbogen and nicotinamide, and the delivery of chemical radiosensitizers. In contrast, bioreductive drugs and hypoxia-targeted suicide gene therapy aim at activating cytotoxic agents at the tumor site, while sparing normal tissue from damage. The cellular machinery responds to hypoxia by activating the expression of genes involved in angiogenesis, anaerobic metabolism, vascular permeability, and inflammation. In most cases, transcription is initiated by the binding of the transcription factor hypoxia-inducible factor (HIF) to hypoxia responsive elements (HREs). Hypoxia-targeting for gene therapy has been achieved by utilizing promoters containing HREs, to induce selective and efficient transgene activation at the tumor site. Hypoxia-targeted delivery and prodrug activation may add additional levels of selectivity to the treatment. In this article, the latest developments of cancer gene therapy of the hypoxic environment are discussed, with particular attention to combined protocols with ionizing radiation. Ultimately, it is proposed that by adopting specific transgene activation and molecular amplification systems, resistant hypoxic tumor tissues may be effectively targeted with gene therapy.
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Affiliation(s)
- Olga Greco
- Department of Radiation Oncology, Karmanos Cancer Institute and Wayne State University, Hudson Webber CRC, Detroit, Michigan, USA.
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19
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Davis AJ, Tannock IF. Tumor physiology and resistance to chemotherapy: repopulation and drug penetration. Cancer Treat Res 2003; 112:1-26. [PMID: 12481709 DOI: 10.1007/978-1-4615-1173-1_1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- Alison J Davis
- Department of Medical Oncology and Hematology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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20
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Therapeutic Significance of Microenvironmental Factors. BLOOD PERFUSION AND MICROENVIRONMENT OF HUMAN TUMORS 2000. [DOI: 10.1007/978-3-642-58813-6_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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21
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Braun RD, Lanzen JL, Dewhirst MW. Fourier analysis of fluctuations of oxygen tension and blood flow in R3230Ac tumors and muscle in rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H551-68. [PMID: 10444480 DOI: 10.1152/ajpheart.1999.277.2.h551] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tumor hypoxia is a major barrier to tumor radiation therapy. Typically tumor hypoxia occurs in two forms: chronic and acute. Although the existence of acute hypoxia has long been acknowledged, its temporal characteristics have never been directly measured and documented. In this study tumor PO(2), blood flow (BF), and arterial blood pressure (BP) were measured simultaneously in nine Fischer 344 rats bearing R3230Ac rat mammary adenocarcinomas in the subcutis of the left hindleg. We measured PO(2) at a single location for 36-125 min using recessed-tip oxygen microelectrodes. Simultaneously, we measured tumor BF at two sites within the tumor using laser-Doppler flowmetry (LDF). Similar recordings were made in the quadriceps muscle of seven non-tumor-bearing rats. The PO(2), tumor BF, and BP records were subjected to Fourier analysis. PO(2) and BF showed low-frequency fluctuations (<2 cycles/min) in both tumor and muscle, but the magnitude of the changes in tumor was greater. Tumor BF showed more activity at low frequencies than muscle BF, and the magnitude tended to be greater. No strong correlations were found between PO(2) and BF power spectra for either tumor or muscle or between the frequency patterns of BP and tumor PO(2) spectra. These results quantitatively demonstrate, for the first time, that BF and PO(2) fluctuate at very low frequencies in tumors. In addition to having biological significance for tumor therapy, these fluctuations may have the potential to alter tumor cell behavior via induction of hypoxia reoxygenation injury and/or altered gene expression.
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Affiliation(s)
- R D Braun
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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22
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Abstract
BACKGROUND AND PURPOSE Doxorubicin is usually an effective radiosensitizer in vitro, but in vivo reports have been more variable. We have examined potential explanations for those observations by comprehensively evaluating doxorubicin and radiation treatments in xenografted human tumors, and in conventional mice with syngeneic tumours. MATERIALS AND METHODS Nude or SCID mice bearing the SiHa cervical squamous cell carcinoma or WiDr colon adenocarcinoma were studied, as were C3H/HeN animals with SCCVII tumours. Assays included a clonogenic assay in combination with cell sorting, laser Doppler flowmetry, and the dual staining mismatch technique. RESULTS Doxorubicin decreased tumour blood flow in all tumour systems, in a dose-dependent fashion with each assay. This resulted in increased tumour hypoxia and decreased response to radiation when inappropriate treatment sequences were employed. However, significant variability from animal to animal was noted. CONCLUSIONS To the extent that these results can be extrapolated to human tumour treatments, we conclude that unless compelling evidence suggests that a tumour will be exceedingly sensitive to the drug, the potential effects of doxorubicin on tumour blood flow contraindicate its administration immediately prior to irradiation.
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Affiliation(s)
- R E Durand
- Medical Biophysics Department, British Columbia Cancer Research Centre, Vancouver, Canada
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Minchinton AI, Wendt KR, Clow KA, Fryer KH. Multilayers of cells growing on a permeable support. An in vitro tumour model. Acta Oncol 1997; 36:13-6. [PMID: 9090957 DOI: 10.3109/02841869709100724] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A system for growing three-dimensional cell culture has been developed which exhibits many features of solid tumours. This system comprises cells growing as a thick mat on a semipermeable membrane suspended in stirred media. SiHa cells grown as these multilayered cell cultures (MCCs) have produced cultures up to ca. 20 cell diameters in thickness. The MCCs, like solid tumours growing in vivo. develop diffusion-dependent necrosis and hypoxia and the cell packing acts as a barrier to the diffusion of drugs. These cultures can, therefore, be used to study aspects of cancer biology and drug transport that are difficult to study using other techniques.
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Affiliation(s)
- A I Minchinton
- Department of Medical Biophysics, B.C. Cancer Research Center, Vancouver, Canada
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Broström LA, Crnalic S, Löfvenberg R, Stenling R, Boquist L. Structure, growth and cell proliferation of human osteosarcoma and malignant fibrous histiocytoma xenografts in serial transplantation in nude mice. APMIS 1996; 104:775-83. [PMID: 8982240 DOI: 10.1111/j.1699-0463.1996.tb04942.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tumour specimens from one patient with osteosarcoma and one with malignant fibrous histiocytoma were transplanted in serial passages in nude mice. Structure, growth and cell kinetics of the xenografts were studied in order to assess the validity of the two tumour models. Cell proliferation was analysed using in vivo labelling with the thymidine analogue iododeoxyuridine (IdUrd) and the IdUrd labelling index (LI) was determined by immunohistochemistry. The DNA index (DI) was examined by flow cytometry. The c-myc oncoprotein expression was studied by immunohistochemistry. More intense proliferation was observed in the peripheral parts of the tumours. There was no correlation between tumour growth and cell proliferation in the two tumour groups. Stability of the tumour models was indicated by low intrapassage and interpassage variations of DI, LI, and volume doubling time, and also by retained histopathological characteristics and c-myc staining patterns of donor patients' tumours during serial transplantation.
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Affiliation(s)
- L A Broström
- Department of Orthopaedics, Umeå University Hospital, Sweden
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25
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Dewhirst MW, Kimura H, Rehmus SW, Braun RD, Papahadjopoulos D, Hong K, Secomb TW. Microvascular studies on the origins of perfusion-limited hypoxia. THE BRITISH JOURNAL OF CANCER. SUPPLEMENT 1996; 27:S247-S251. [PMID: 8763890 PMCID: PMC2149984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Two forms of hypoxia are thought to exist in tumours: (1) hypoxia caused by limitations of its diffusion (chronic hypoxia); and (2) hypoxia caused by changes in perfusion (acute hypoxia). Indirect information suggests the existence of perfusion-limited hypoxia, but there is no direct proof that fluctuations in blood flow can lead to hypoxia, nor is there any information regarding potential causes of fluctuant flow. In this study, we have begun to explore these questions using R3230AC tumours transplanted into rat dorsal-flap window chambers. Two types of fluctuant flow have been observed. The first type, usually confined to single vessels, is typified by instability of flow magnitude and direction, and total vascular stasis occurs, but only for a few seconds at a time (4% incidence). The second type of fluctuation occurs in groups of vessels and is cyclic, with cycle times ranging from 20-60 min. Total vascular stasis does not necessarily occur, but the fluctuations in red cell flux are accompanied by changes in vascular oxygen content, as measured by microelectrodes. Another source of chronic hypoxia has also been identified in these experiments. Nine per cent (9%) of vessels examined had plasma flow, but very low or absent red cell flux over periods of many minutes.
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Affiliation(s)
- M W Dewhirst
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
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Kotelnikov VM, Coon JS, Taylor S, Hutchinson J, Panje W, Caldarelli DD, LaFollette S, Preisler HD. In vivo labelling with halogenated pyrimidines of squamous cell carcinomas and adjacent non-involved mucosa of head and neck region. Cell Prolif 1995; 28:497-509. [PMID: 7578599 DOI: 10.1111/j.1365-2184.1995.tb00088.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The frequency and distribution of labelled cells were studied immunohistochemically in 37 squamous cell carcinomas (SCC) of head and neck after in vivo infusion of IdUrd and BrdUrd. Tumours were classified according to their labelling patterns. Low and moderate grade SCC consisted of tumour islands separated by interstitial tissue. In some tumours labelled cells only appeared near the basal layer while in others proliferative cells were evenly distributed within the neoplastic island. In anaplastic carcinomas labelled cells were distributed either randomly or around blood vessels (cord structures). While the basal layer in adjacent normal epithelium contained very few labelled cells (LI = 1.6 +/- 0.2%), the LI of basal cells in tumour islands were much higher than the average LI of the tumour (47.2 +/- 2.8% and 23.8 +/- 1.6%, respectively). In patients who had received cytotoxic therapy up to two months before the biopsy, the LI in the basal layer of normal epithelium was 19.0 +/- 3.5%. In sequential biopsies obtained 1-2 weeks after the infusion of IdUrd and BrdUrd some labelled tumour cells were found in necrotic foci and in pearl structures. Additionally, in six tumours, we found areas of cells labelled with IdUrd alone, even though the IdUrd infusion had been followed by a BrdUrd infusion 1 h later. This is in agreement with the phenomenon of intermittent tumour blood flow described earlier in experimental tumours.
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Affiliation(s)
- V M Kotelnikov
- Rush Cancer Institute, Department of Medicine, Rush-Presbyterian-St Luke's Medical Center, Chicago, IL 60612-3833, USA
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27
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Abstract
Studies of transplantable rodent tumours have suggested that malignant tissue might experience transient perfusion at the microvascular level. The purpose of the work reported here was to investigate whether transient perfusion can be demonstrated in xenografted human tumours. Tumours of four melanoma lines (A-07, D-12, R-18, U-25), grown orthotopically in Balb/c nu/nu mice, were included in the study. Transient perfusion was studied by using the double-fluorescent staining technique. Hoechst 33342 and DiOC7(3) were either administered simultaneously or Hoechst 33342 was administered 20 min before DiOC7(3). Detection of transient perfusion by this method requires that vessels are non-functional for at least 5 min owing to the distribution half-lives of the dyes in the blood. Usable combinations of dye concentrations were found by varying the concentrations of Hoechst 33342 and DiOC7(3) systematically. The level of perfusion mismatch following simultaneous administration of the dyes ranged from approximately 1.5% for U-25 tumours to approximately 3.0% for R-18 tumours at these combinations. Moreover, the fraction of vessels stained only with Hoechst 33342 and the fraction of vessels stained only with DiOC7(3) were not significantly different whether the dyes were administered simultaneously or sequentially. Transient perfusion could not be demonstrated in any of the tumour lines. Thus, the fraction of vessels stained only with Hoechst 33342 and the fraction of vessels stained only with DiOC7(3) were not significantly higher after sequential than after simultaneous administration of the dyes. Moreover, the vessels stained only with Hoechst 33342 and the vessels stained only with DiOC7(3) were randomly distributed within the tumours whether the dyes were administered simultaneously or sequentially. Consequently, acute hypoxia caused by transient perfusion is probably a less pronounced phenomenon in malignant tissue than previous studies of rodent tumours have suggested.
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Affiliation(s)
- I Tufto
- Institute for Cancer Research, Norwegian Radium Hospital, Montebello, Oslo
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28
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Abstract
PURPOSE To test the hypothesis that, following preferential killing of tumor hypoxic cells, the fraction of hypoxic cells in the tumor will reestablish itself to pretreatment levels (rehypoxiation) with the same kinetics as for reoxygenation. METHODS AND MATERIALS Mouse squamous cell carcinoma VII (SCCVII) tumors were treated with a single dose of 10 Gy or a single dose of the bioreductive hypoxic cell cytotoxin, tirapazamine (SR 4233, 0.2 mmol/kg), which preferentially kills hypoxic cells within the tumor. Hypoxic fractions were determined by the paired survival curve technique using the in vivo-in vitro clonogenic assay 0-24 h after treatment. RESULTS Immediately after irradiation with 10 Gy, the hypoxic fraction of the tumors increased to 80% and rapidly returned to pretreatment levels 3-6 h later. Within 1 h of injecting tirapazamine, the hypoxic fraction fell to 0.57% (about 7% of pretreatment levels) and returned to pretreatment levels 3-5 h later. CONCLUSION The return to pretreatment levels of hypoxia among tumor cells surviving a single dose of radiation (reoxygenation) and of the hypoxic cell toxin tirapazamine (rehypoxiation) was rapid and occurred with similar kinetics for the two processes. These data support the hypothesis that reoxygenation and rehypoxiation are different manifestations of the same phenomenon and result from fluctuating tumor blood flow which creates acute hypoxia.
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Affiliation(s)
- I H Kim
- Department of Radiation Oncology, Stanford University School of Medicine, CA 94305-5468
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29
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Rofstad EK, Steinsland E, Kaalhus O, Chang YB, Høvik B, Lyng H. Magnetic resonance imaging of human melanoma xenografts in vivo: proton spin-lattice and spin-spin relaxation times versus fractional tumour water content and fraction of necrotic tumour tissue. Int J Radiat Biol 1994; 65:387-401. [PMID: 7908318 DOI: 10.1080/09553009414550451] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Proton nuclear magnetic resonance (1H-nmr) imaging is used routinely in clinical oncology to provide macroscopic anatomical information, whereas its potential to provide physiological information about tumours is not well explored. To evaluate the potential usefulness of 1H-nmr imaging in the prediction of tumour treatment resistance caused by unfavourable microenvironmental conditions, possible correlations between proton spin-lattice and spin-spin relaxation times (T1 and T2) and physiological parameters of the tumour microenvironment were investigated. Tumours from six human melanoma xenograft lines were included in the study. 1H-nmr imaging was performed at 1.5 T using spin-echo pulse sequences. T1- and T2-distributions were generated from the images. Fractional tumour water content and the fraction of necrotic tumour tissue were measured immediately after 1H-nmr imaging. Significant correlations across tumour lines were found for T1 and T2 versus fractional tumour water content (p < 0.001) as well as for T1 and T2 versus fraction of necrotic tumour tissue (p < 0.05). Tumours with high fractional water contents had high values of T1 and T2, probably caused by free water in the tumour interstitium. Fractional water content is correlated to interstitial fluid pressure in tumours, high interstitial fluid pressure being indicative of high vascular resistance. Tumours with high fractional water contents are thus expected to show regions with radiobiologically hypoxic cells as well as poor intravascular and interstitial transport of many therapeutic agents. T1 and T2 decreased with increasing fraction of necrotic tumour tissue, perhaps because complexed paramagnetic ions were released during development of necrosis. Viable tumour cells adjacent to necrotic regions are usually chronically hypoxic. Tumours with high fractions of necrotic tissue are thus expected to contain significant proportions of radiobiologically hypoxic cells. Consequently, quantitative 1H-nmr imaging has the potential to be developed as an efficient clinical tool in prediction of tumour treatment resistance caused by hypoxia and/or transport barriers for therapeutic agents. However, much work remains to be done before this potential can be adequately evaluated. One problem is that high fractional tumour water contents result in longer T1 and T2 whereas high fractions of necrotic tumour tissue result in shorter T1 and T2; i.e. the two parameters which are indicative of treatment resistance contribute in opposite directions. Another problem is that the correlations for T1 and T2 versus fraction of necrotic tumour tissue are not particularly strong.
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Affiliation(s)
- E K Rofstad
- Department of Biophysics, Norwegian Radium Hospital, Montebello, Oslo
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Boyer MJ, Barnard M, Hedley DW, Tannock IF. Regulation of intracellular pH in subpopulations of cells derived from spheroids and solid tumours. Br J Cancer 1993; 68:890-7. [PMID: 8217605 PMCID: PMC1968730 DOI: 10.1038/bjc.1993.451] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Solid tumours are known to develop regions of extracellular acidity and survival of tumour cells in such regions depends on membrane-based mechanisms which regulate intracellular pH (pHi). We have therefore developed a method, based on dual staining of cells and flow cytometry, to study the regulation of pHi in subpopulations of tumours and spheroids. The activity of membrane-based pHi regulating transporters was studied in EMT-6 and MGH U1 cells grown in monolayer culture, spheroids, and tumours. pHi was measured with the fluorescent pH probe 2'7'-bis-(2-carboxyethyl)-5-(and-6)carboxyfluorescein, and Hoechst 33342 was used to identify cells from different regions of tumours and spheroids. In monolayer culture, incubation of cells for 18 h at pHe 6.6 led to a 1.3-1.5-fold enhancement in the activity of both the Na+/H+ exchanger and the Na(+)-dependent Cl-@HCO3- exchanger. This effect was prevented by the protein synthesis inhibitor cycloheximide. Cells from the centre of EMT-6 spheroids had increased activity of the Na+/H+ exchanger compared to cells from the periphery, when spheroids were grown in medium at pH 6.6, but not at 7.4. By contrast, in MGH U1 spheroids, cells from the centre had increased activity of the Na+/H+ antiport under both sets of conditions. There was no significant difference in the activity of the Na+/H+ exchanger in cells derived from different subpopulations of EMT-6 tumours or MGH U1 xenografts in nude mice. Although upregulation of Na+/H+ exchange occurs after exposure to acidic conditions in vitro, the microenvironmental conditions found within solid tumours do not appear to cause this effect. Our results suggest the feasibility of pharmacological inhibition of Na+/H+ exchange activity as an approach to therapy directed against nutrient-deprived tumour cells.
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Affiliation(s)
- M J Boyer
- Department of Medicine, Ontario Cancer Institute, Toronto, Canada
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31
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Baisch H, Otto U. Intratumoral heterogeneity of S phase transition in solid tumours determined by bromodeoxyuridine labelling and flow cytometry. Cell Prolif 1993; 26:439-48. [PMID: 9087534 DOI: 10.1111/j.1365-2184.1993.tb00131.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cell kinetics of human renal cell carcinomas xenotransplanted into nu/nu mice were analysed using the bromodeoxyuridine (BrdUrd) labelling method. Tumours were removed 0.5-14 h after injection of the BrdUrd solution. The tumour cells were stained with fluorescein isothiocyanate conjugated anti-BrdUrd antibodies and propidium iodide (DNA content). From the flow cytometry data the relative movement was calculated. Relative movement data of variable intervals after BrdUrd labelling were subjected to a fit procedure using log-normal distributions for S phase transition (T(s)). The log-normal distributions were modified by inflation factors in order to get extremely asymmetric distributions. The best fits to the experimental data were obtained using wide asymmetric T(s) distributions, indicating that progression through S phase in solid human tumours is considerably heterogeneous. This implies that the potential doubling time (T(pot)) is longer than calculated from a single measured relative movement value obtained a few hours after BrdUrd labelling.
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Affiliation(s)
- H Baisch
- Institute of Biophysics and Radiobiology, Hamburg, Germany
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Chaplin DJ, Horsman MR, Siemann DW. Further evaluation of nicotinamide and carbogen as a strategy to reoxygenate hypoxic cells in vivo: importance of nicotinamide dose and pre-irradiation breathing time. Br J Cancer 1993; 68:269-73. [PMID: 8347481 PMCID: PMC1968547 DOI: 10.1038/bjc.1993.326] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The combination of nicotinamide and carbogen breathing is awaiting clinical evaluation as a strategy to overcome tumour hypoxia and thus enhance radiation response. We have continued our evaluation of this approach in the murine SCCVII tumour with the aim of determining the importance of nicotinamide dose and the pre-irradiation breathing time (PIBT) for carbogen. For carbogen breathing alone maximal enhancement of radiation response was observed with PIBT's of between 5 and 30 min. When nicotinamide (1,000 mg kg-1 IP) was administered 60 min prior to irradiation little or no variation in radiation response was observed for all the PIBT's examined (5-90 min). Indeed at all PIBT's the cell survival obtained for the carbogen nicotinamide and radiation combination was indistinguishable from that expected for a fully aerobic response. For PIBT's of 15 and 60 min we examined the influence of nicotinamide doses between 50 and 1,000 mg kg-1. Significant radiosensitizing effects were observed for all nicotinamide doses tested above 50 mg kg-1. Moreover for doses of 250 mg kg-1 and above the cell survival data was consistent with that expected for a fully aerobic response. No additional benefit accrued from raising the nicotinamide dose above 250 mg kg-1. These results indicate that significant radiosensitization may be expected even with clinically achievable nicotinamide doses when it is combined with carbogen breathing. Furthermore, the use of nicotinamide may reduce the critical importance of PIBT on the radiosensitization observed with carbogen.
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Affiliation(s)
- D J Chaplin
- Medical Biophysics Unit, B.C. Cancer Research Centre, Vancouver, Canada
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Newell K, Wood P, Stratford I, Tannock I. Effects of agents which inhibit the regulation of intracellular pH on murine solid tumours. Br J Cancer 1992; 66:311-7. [PMID: 1503904 PMCID: PMC1977830 DOI: 10.1038/bjc.1992.262] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cell killing can be achieved in an acidic environment in tissue culture (medium pH less than 7.0) by agents (nigericin, carbonylcyanide-3-chlorophenylhydrazone (CCCP)) which transport protons from the extracellular space into the cytoplasm. Cell killing is enhanced when these agents are used in combination with compounds (amiloride, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)) which inhibit the membrane-based exchangers responsible for the regulation of intracellular pH (pHi). We describe experiments which assess the ability of these agents to kill tumour cells in spheroids and in vivo. Both nigericin and CCCP were observed to penetrate tissue based on their ability to kill tumour cells in spheroids. The mean extracellular pH (pHe) of the KHT fibrosarcoma and the EMT-6 sarcoma were observed to be 0.21 and 0.32 pH units more acidic than the mean pHe in muscle tissue. Intraperitoneal (i.p.) administration of the vasodilator hydralazine (10 mg kg-1) caused a reduction of the mean pHe of the KHT but not the EMT-6 tumour. Nigericin (2.5 mg kg-1, i.p.) plus amiloride (10 mg kg-1, i.p.) followed 30 min later by hydralazine (10 mg kg-1, i.p.) reduced the surviving fraction of cells in the KHT and EMT-6 tumours, but had minimal effects on growth delay. When KHT tumours were treated with 15 Gy X-rays followed immediately by nigericin plus amiloride and hydralazine a reduced surviving fraction as well as an increase in tumour growth delay was observed compared to radiation alone. The administration of nigericin (2.5 mg kg-1, i.p.) or the combination of nigericin (2.5 mg kg-1, i.p.) followed by hydralazine (10 mg kg-1, intravenous (i.v.)) resulted in reductions of tumour pHi of 0.27 and 0.29 pH units respectively as determined by 31P magnetic resonance spectroscopy (MRS). Our results show that the combination of nigericin and hydralazine (with or without amiloride) can kill cells in rodent solid tumours and that cell killing is associated with a reduction in the mean pHi of tumour cells.
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Affiliation(s)
- K Newell
- Department of Medical Biophysics, University of Toronto, Ontario, Canada
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Minchinton AI, Brown JM. Improving the effectiveness of the bioreductive antitumor agent SR 4233 by induced hypoxia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1992; 317:177-81. [PMID: 1288125 DOI: 10.1007/978-1-4615-3428-0_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- A I Minchinton
- Stanford University Medical Center, Division of Radiation Biology, Stanford University, CA 94305-5105
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Freitas I, Baronzio GF. Tumor hypoxia, reoxygenation and oxygenation strategies: possible role in photodynamic therapy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1991; 11:3-30. [PMID: 1791492 DOI: 10.1016/1011-1344(91)80264-i] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The concept of hypoxia and its role in tumor therapy are currently under re-evaluation. Poor oxygenation is no longer visualized as an independent feature promoting necrosis and resistance to treatments, but rather as one of the several interdependent microenvironmental parameters associated with impaired blood perfusion. Tumor cells display several survival strategies and remain clonogenic for long periods in nutrient-deprived situations. Reoxygenation may cause lethal damage, improve the response to therapy, or else allow the cell variants adapted to hypoxia to resume proliferation with enhanced aggressiveness and resistance to treatment. The blood supply parameters, oxygenation status and metabolism of malignant cells are discussed here from the standpoint of tumor photodynamic therapy. The role of the tumor interstitial fluid as oxygen- and sensitizer-carrier is discussed. Techniques for assessing tumor oxygenation and for mapping hypoxic territories are described. Strategies for locally improving the oxygenation levels or for selectively destroying the hypoxic populations are outlined.
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Affiliation(s)
- I Freitas
- Department of Animal Biology, University of Pavia, Italy
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36
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Abstract
It has been established that malignant tissue as a consequence of abnormal morphogenesis has a structurally abnormal blood supply. These structural and as a consequence functional differences between normal and neoplastic vasculature provide a basis for selective modulation of tumour vascular function. Agents have been identified which can induce both irreversible and reversible effects on tumour blood flow. Hyperthermia, photodynamic therapy, tumour necrosis factor and flavone acetic acid are known to elicit most of their anti-tumour effect via irreversible changes in tumour vascular function. In addition to the extensive tumour cell kill and thus therapeutic potential provided by such chronic modulation of blood flow, acute transient changes in macroregional and microregional tumour blood flow could also play an important role if used appropriately with conventional therapies. The use of this latter type of modulation is discussed with reference to known examples of such 'vasoactive' compounds. It is also emphasized that blood flow changes induced in tumour tissue can be a 'double-edged sword' with detrimental consequences for therapeutic outcome if inappropriate changes are induced, for example, reductions in flow at the time of conventional radiotherapy or chemotherapy by agents not considered to be 'vasoactive'. To emphasize this point examples of blood flow modulation by pimonidazole and cis-platinum, agents that are used in conjunction with radiotherapy, are described.
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Affiliation(s)
- D J Chaplin
- Medical Biophysics Unit, B.C. Cancer Research Centre, Vancouver, Canada
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Trotter MJ, Chaplin DJ, Olive PL. Possible mechanisms for intermittent blood flow in the murine SCCVII carcinoma. Int J Radiat Biol 1991; 60:139-46. [PMID: 1677962 DOI: 10.1080/09553009114551731] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- M J Trotter
- British Columbia Cancer Research Centre, Vancouver, Canada
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38
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Minchinton AI, Chaplin DJ. Spatial characterization of glutathione depletion in the KHT sarcoma using flow cytometry. Int J Radiat Biol 1991; 59:1425-33. [PMID: 1677386 DOI: 10.1080/09553009114551271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Intravenous administration of the fluorescent DNA stain Hoechst 33342 to tumour-bearing mice was used to label cells proportionally to their proximity from the vasculature. Flow cytometry was used to sort cells from the tumour into populations based on their Hoechst 33342-derived fluorescence. The cell populations were then assayed for their glutathione (GSH) content and their radiosensitivity. Tumours from mice pretreated with buthionine sulphoximine (BSO) were compared with untreated animals. The major findings of this study suggest that the cellular GSH concentration within tumours decreases with distance from the vasculature, and that the GSH concentration within cells from all locations in the tumour can be depleted by enzymatically inhibiting its synthesis using BSO. This depletion of GSH resulted in a small degree of hypoxic radiosensitization of cells both distal and proximal to the vasculature.
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39
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Chaplin DJ, Horsman MR, Aoki DS. Nicotinamide, Fluosol DA and Carbogen: a strategy to reoxygenate acutely and chronically hypoxic cells in vivo. Br J Cancer 1991; 63:109-13. [PMID: 1846549 PMCID: PMC1971634 DOI: 10.1038/bjc.1991.22] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The effect of Nicotinamide and/or treatment with Fluosol DA and Carbogen breathing on the radiation response of 500-750 mg SCCVII and KHT tumours has been evaluated. Pretreatment with Fluosol DA/Carbogen or Nicotinamide resulted in relatively modest enhancements of radiation damage with enhancement factors of 1.1 and 1.3 being observed using an in vivo/in vitro clonogenic end-point. A combination of Nicotinamide and Fluosol DA/Carbogen resulted in a larger enhancement factor of 1.6 over the radiation dose ranges studied. These modification factors reflect a value close to that expected for a fully aerobic response in this survival range. Growth delay studies in the SCCVII tumour provided similar results. Using a recently developed fluorescence activated cell sorting technique, which utilizes the in vivo pharmacokinetic and DNA binding properties of the bisbenzamide stain Hoechst 33342, the effect of Nicotinamide and/or Fluosol DA/Carbogen schedules on the occurrence of acute hypoxia was assessed. The results clearly show that Nicotinamide significantly reduces the amount of 'acute hypoxia', but has a lesser effect on 'chronic' hypoxic cells. However, combinations of Nicotinamide and Fluosol DA/Carbogen significantly increase the response of both 'acutely' and 'chronically hypoxic' cells. The results provide evidence that a combination of Nicotinamide and Fluosol DA/Carbogen can provide an effective way of reoxygenating both acutely and chronically hypoxic cells.
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MESH Headings
- Animals
- Carbon Dioxide/pharmacology
- Carcinoma, Small Cell/drug therapy
- Carcinoma, Small Cell/pathology
- Carcinoma, Small Cell/radiotherapy
- Cell Hypoxia/drug effects
- Cell Hypoxia/radiation effects
- Cell Survival/drug effects
- Cell Survival/radiation effects
- Dose-Response Relationship, Radiation
- Drug Combinations
- Drug Therapy, Combination
- Female
- Fluorocarbons/pharmacology
- Hydroxyethyl Starch Derivatives
- Mice
- Mice, Inbred Strains
- Neoplasm Transplantation
- Neoplasms, Experimental/drug therapy
- Neoplasms, Experimental/pathology
- Neoplasms, Experimental/radiotherapy
- Niacinamide/pharmacology
- Oxygen/metabolism
- Oxygen/pharmacology
- Radiation-Sensitizing Agents/pharmacology
- Sarcoma, Experimental/drug therapy
- Sarcoma, Experimental/pathology
- Sarcoma, Experimental/radiotherapy
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Affiliation(s)
- D J Chaplin
- Medical Biophysics Unit, B.C. Cancer Research Centre, Vancouver, Canada
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40
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Blumenthal RD, Fand I, Sharkey RM, Boerman OC, Kashi R, Goldenberg DM. The effect of antibody protein dose on the uniformity of tumor distribution of radioantibodies: an autoradiographic study. Cancer Immunol Immunother 1991; 33:351-8. [PMID: 1652355 PMCID: PMC11038242 DOI: 10.1007/bf01741594] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/1991] [Accepted: 05/08/1991] [Indexed: 12/28/2022]
Abstract
The inaccessibility of radiolabeled antibody to poorly vascularized regions of solid tumors may reduce the therapeutic efficacy of these macromolecules. Theoretical mathematical models have predicted that increasing the protein dose administered would reduce the heterogeneity of radioantibody distribution. This investigation was undertaken to evaluate this hypothesis in experimental animal models. We have utilized the technique of macroautoradiography to demonstrate an increase in tumor penetration of the lower-affinity 125I-labeled NP-4 or higher-affinity Immu-14 anti-carcinoembryonic antigen (anti-CEA) mAbs into small (60.25-0.4 g) and large (0.8-1.5 g) GW-39 and LS174T human colonic xenografts, grown subcutaneously in the nude mouse, when 400 micrograms unlabeled antibody is administered simultaneously with 10 micrograms (100 microCi) radioantibody. Further increases in protein to 800 micrograms result in a reduction in total tumor uptake of the antibody. These in a reduction in total tumor uptake of the antibody. These differences in mAb distribution could be visualized as early as 1 day after antibody injection. Improved mAb penetration was also achieved for the Mu-9 anti-CSAp (anti-mucin) antibody using 800 micrograms unlabeled antibody. An irrelevant antibody (AFP-7-31) was found to be homogeneously distributed 3 days after injection, even at a low protein dose. Attempts to improve mAb penetration by increasing the protein dose in the GS-2 colorectal tumor, a model that has low NP-4 accretion as a result physiological barriers separating antibody from antigen, were not successful. These results suggest that a more homogeneous distribution of radioantibody can be achieved by carefully selecting a dose of unlabeled antibody to coadminister. Work is currently in progress to determine the effect of improved tumor distribution of radioantibody on the therapeutic potential of a single dose of radioantibody.
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Trotter MJ, Olive PL, Chaplin DJ. Effect of vascular marker Hoechst 33342 on tumour perfusion and cardiovascular function in the mouse. Br J Cancer 1990; 62:903-8. [PMID: 2257217 PMCID: PMC1971547 DOI: 10.1038/bjc.1990.406] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The fluorescent stain Hoechst 33342 (H33342) has been employed extensively as an in vivo marker of functional tumour vasculature. We have found that H33342 causes a transient, dose-dependent decrease in tumour red blood cell (RBC) flow in SCCVII tumours as measured using laser Doppler flowmetry. After intravenous bolus injection of 15 mg kg-1 to anaesthetised mice, blood flow in subcutaneous back tumours declined to 19 +/- 11% of pretreatment values, returning to normal in less than 7 min. The effect was less pronounced in mice bearing foot tumours in which flow decreased to 52 +/- 14% of pretreatment values in unanaesthetised mice and to 50 +/- 15% in anaesthetised animals. RBC flow in foot tumours remained significantly depressed for only 2-3 min. A dose of 5 mg kg-1 was not significantly vasoactive in back tumours. H33342 also caused a transient 20 +/- 6 mmHg decline in mouse arterial blood pressure. Blood pH and haematocrit, and tumour cell oxygen consumption were unchanged by H33342. H33342-induced flow changes did not affect results obtained using an in vivo double staining protocol provided that the interval between stain injections was greater than 5 min. Due to its transient effects on tumour perfusion, the stain caused radiobiological tumour hypoxia if injected immediately prior to X-irradiation. Injection 20 min before irradiation had no influence on tumour radiation response. We conclude that the transient nature of H33342-induced perturbations in mouse cardiovascular physiology and tumour blood flow must always be considered but do not preclude the use of the stain as a vascular marker to detect spontaneous tumour blood flow fluctuations or acute hypoxia.
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Affiliation(s)
- M J Trotter
- Medical Biophysics Unit, BC Cancer Research Centre, Vancouver, Canada
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