1
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Saha PS, Yan J, Zhu C. Diffuse reflectance spectroscopy for optical characterizations of orthotopic head and neck cancer models in vivo. BIOMEDICAL OPTICS EXPRESS 2024; 15:4176-4189. [PMID: 39022549 PMCID: PMC11249676 DOI: 10.1364/boe.528608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 07/20/2024]
Abstract
We demonstrated an easy-to-build, portable diffuse reflectance spectroscopy device along with a Monte Carlo inverse model to quantify tissue absorption and scattering-based parameters of orthotopic head and neck cancer models in vivo. Both tissue-mimicking phantom studies and animal studies were conducted to verify the optical spectroscopy system and Monte Carlo inverse model for the accurate extraction of tissue optical properties. For the first time, we reported the tissue absorption and scattering coefficients of mouse normal tongue tissues and tongue tumor tissues. Our in vivo animal studies showed reduced total hemoglobin concentration, lower tissue vascular oxygen saturation, and increased tissue scattering in the orthotopic tongue tumors compared to the normal tongue tissues. Our data also showed that mice tongue tumors with different sizes may have significantly different tissue absorption and scattering-based parameters. Small tongue tumors (volume was ∼60 mm3) had increased absorption coefficients, decreased reduced-scattering coefficients, and increased total hemoglobin concentrations compared to tiny tongue tumors (volume was ∼18 mm3). These results demonstrated the potential of diffuse reflectance spectroscopy to noninvasively evaluate tumor biology using orthotopic tongue cancer models for future head and neck cancer research.
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Affiliation(s)
- Pranto Soumik Saha
- Department of Biomedical Engineering, University of Kentucky
, Lexington, KY 40506, USA
| | - Jing Yan
- Department of Biomedical Engineering, University of Kentucky
, Lexington, KY 40506, USA
| | - Caigang Zhu
- Department of Biomedical Engineering, University of Kentucky
, Lexington, KY 40506, USA
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2
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Rodriguez Troncoso J, Marium Mim U, Ivers JD, Paidi SK, Harper MG, Nguyen KG, Ravindranathan S, Rebello L, Lee DE, Zaharoff DA, Barman I, Rajaram N. Evaluating differences in optical properties of indolent and aggressive murine breast tumors using quantitative diffuse reflectance spectroscopy. BIOMEDICAL OPTICS EXPRESS 2023; 14:6114-6126. [PMID: 38420330 PMCID: PMC10898562 DOI: 10.1364/boe.505153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/06/2023] [Accepted: 10/26/2023] [Indexed: 03/02/2024]
Abstract
We used diffuse reflectance spectroscopy to quantify tissue absorption and scattering-based parameters in similarly sized tumors derived from a panel of four isogenic murine breast cancer cell lines (4T1, 4T07, 168FARN, 67NR) that are each capable of accomplishing different steps of the invasion-metastasis cascade. We found lower tissue scattering, increased hemoglobin concentration, and lower vascular oxygenation in indolent 67NR tumors incapable of metastasis compared with aggressive 4T1 tumors capable of metastasis. Supervised learning statistical approaches were able to accurately differentiate between tumor groups and classify tumors according to their ability to accomplish each step of the invasion-metastasis cascade. We investigated whether the inhibition of metastasis-promoting genes in the highly metastatic 4T1 tumors resulted in measurable optical changes that made these tumors similar to the indolent 67NR tumors. These results demonstrate the potential of diffuse reflectance spectroscopy to noninvasively evaluate tumor biology and discriminate between indolent and aggressive tumors.
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Affiliation(s)
| | - Umme Marium Mim
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Jesse D. Ivers
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Santosh K. Paidi
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Mason G. Harper
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Khue G. Nguyen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Sruthi Ravindranathan
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Lisa Rebello
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA
| | - David E. Lee
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA
- Department of Exercise Science, University of Arkansas, Fayetteville, AR 72703, USA
| | - David A. Zaharoff
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC 27695, USA
| | - Ishan Barman
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Narasimhan Rajaram
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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3
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Deutsch RJ, D’Agostino VW, Sunassee ED, Kwan M, Madonna MC, Palmer G, Crouch BT, Ramanujam N. A Spectroscopic Technique to Simultaneously Characterize Fatty Acid Uptake, Mitochondrial Activity, Vascularity, and Oxygen Saturation for Longitudinal Studies In Vivo. Metabolites 2022; 12:metabo12050369. [PMID: 35629873 PMCID: PMC9143017 DOI: 10.3390/metabo12050369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 11/16/2022] Open
Abstract
Aggressive breast cancer has been shown to shift its metabolism towards increased lipid catabolism as the primary carbon source for oxidative phosphorylation. In this study, we present a technique to longitudinally monitor lipid metabolism and oxidative phosphorylation in pre-clinical tumor models to investigate the metabolic changes with mammary tissue development and characterize metabolic differences between primary murine breast cancer and normal mammary tissue. We used optical spectroscopy to measure the signal of two simultaneously injected exogenous fluorescent metabolic reporters: TMRE (oxidative phosphorylation surrogate) and Bodipy FL C16 (lipid catabolism surrogate). We leverage an inverse Monte Carlo algorithm to correct for aberrations resulting from tissue optical properties and to extract vascular endpoints relevant to oxidative metabolism, specifically oxygen saturation (SO2) and hemoglobin concentration ([Hb]). We extensively validated our optical method to demonstrate that our two fluorescent metabolic endpoints can be measured without chemical or optical crosstalk and that dual measurements of both fluorophores in vivo faithfully recapitulate the measurements of each fluorophore independently. We then applied our method to track the metabolism of growing 4T1 and 67NR breast tumors and aging mammary tissue, all highly metabolic tissue types. Our results show the changes in metabolism as a function of mammary age and tumor growth, and these changes can be best distinguished through the combination of endpoints measured with our system. Clustering analysis incorporating both Bodipy FL C16 and TMRE endpoints combined with either SO2 or [Hb] proved to be the most effective in minimizing intra-group variance and maximizing inter-group differences. Our platform can be extended to applications in which long-term metabolic flexibility is important to study, for example in tumor regression, recurrence following dormancy, and responses to cancer treatment.
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Affiliation(s)
- Riley J. Deutsch
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; (R.J.D.); (E.D.S.); (M.C.M.); (B.T.C.); (N.R.)
| | - Victoria W. D’Agostino
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; (R.J.D.); (E.D.S.); (M.C.M.); (B.T.C.); (N.R.)
- Correspondence:
| | - Enakshi D. Sunassee
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; (R.J.D.); (E.D.S.); (M.C.M.); (B.T.C.); (N.R.)
| | - Michelle Kwan
- Department of Biology, Duke University, Durham, NC 27708, USA;
| | - Megan C. Madonna
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; (R.J.D.); (E.D.S.); (M.C.M.); (B.T.C.); (N.R.)
| | - Gregory Palmer
- Department of Radiation Oncology, Duke University, Durham, NC 27708, USA;
| | - Brian T. Crouch
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; (R.J.D.); (E.D.S.); (M.C.M.); (B.T.C.); (N.R.)
| | - Nimmi Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; (R.J.D.); (E.D.S.); (M.C.M.); (B.T.C.); (N.R.)
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27708, USA
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4
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Rapid Quantification of Tissue Perfusion Properties with a Two-Stage Look-Up Table. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12083745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Tissue perfusion properties reveal crucial information pertinent to clinical diagnosis and treatment. Multispectral spatial frequency domain imaging (SFDI) is an emerging imaging technique that has been widely used to quantify tissue perfusion properties. However, slow processing speed limits its usefulness in real-time imaging applications. In this study, we present a two-stage look-up table (LUT) approach that accurately and rapidly quantifies optical (absorption and reduced scattering maps) and perfusion (total hemoglobin and oxygen saturation maps) properties using stage-1 and stage-2 LUTs, respectively, based on reflectance images at 660 and 850 nm. The two-stage LUT can be implemented on both CPU and GPU computing platforms. Quantifying tissue perfusion properties using the simulated diffuse reflectance images, we achieved a quantification speed of 266, 174, and 74 frames per second for three image sizes 512 × 512, 1024 × 1024, and 2048 × 2048 pixels, respectively. Quantification of tissue perfusion properties was highly accurate with only 3.5% and 2.5% error for total hemoglobin and oxygen saturation quantification, respectively. The two-stage LUT has the potential to be integrated with dual-sensor cameras to enable real-time quantification of tissue hemodynamics.
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5
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Solingapuram Sai KK, Chen X, Li Z, Zhu C, Shukla K, Forshaw TE, Wu H, Vance SA, Pathirannahel BL, Madonna M, Dewhirst MW, Tsang AW, Poole LB, Ramanujam N, King SB, Furdui CM. [ 18F]Fluoro-DCP, a first generation PET radiotracer for monitoring protein sulfenylation in vivo. Redox Biol 2022; 49:102218. [PMID: 34952463 PMCID: PMC8715125 DOI: 10.1016/j.redox.2021.102218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/12/2021] [Accepted: 12/17/2021] [Indexed: 12/23/2022] Open
Abstract
Redox metabolism plays essential functions in the pathology of cancer and many other diseases. While several radiotracers for imaging redox metabolism have been developed, there are no reports of radiotracers for in vivo imaging of protein oxidation. Here we take the first step towards this goal and describe the synthesis and kinetic properties of a new positron emission tomography (PET) [18F]Fluoro-DCP radiotracer for in vivo imaging of protein sulfenylation. Time course biodistribution and PET/CT studies using xenograft animal models of Head and Neck Squamous Cell Cancer (HNSCC) demonstrate its capability to distinguish between tumors with radiation sensitive and resistant phenotypes consistent with previous reports of decreased protein sulfenylation in clinical specimens of radiation resistant HNSCC. We envision further development of this technology to aid research efforts towards improving diagnosis of patients with radiation resistant tumors.
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Affiliation(s)
| | - Xiaofei Chen
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Zhe Li
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Caigang Zhu
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Kirtikar Shukla
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Tom E Forshaw
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Hanzhi Wu
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Stephen A Vance
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA
| | | | - Megan Madonna
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Mark W Dewhirst
- Department of Radiation Oncology, Duke University, Durham, NC, USA
| | - Allen W Tsang
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Leslie B Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Nimmi Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - S Bruce King
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Cristina M Furdui
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
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6
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Yang B. Rapid quantification of tissue perfusion properties with a two-stage look-up table: a simulation study.. [DOI: 10.1101/2021.11.04.467306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
AbstractTissue perfusion properties reveal crucial information pertinent to clinical diagnosis and treatment. Multispectral spatial frequency domain imaging (SFDI) is an emerging imaging technique that has been widely used to quantify tissue perfusion properties. However, slow processing speed limits its usefulness in real-time imaging applications. In this study, we present a two-stage look-up table (LUT) approach that accurately and rapidly quantifies optical (absorption and reduced scattering maps) and perfusion (total hemoglobin and oxygen saturation maps) properties using stage-1 and stage-2 LUTs, respectively, based on reflectance images at 660nm and 850nm. The two-stage LUT can be implemented on both CPU and GPU computing platforms. Quantifying tissue perfusion properties using the simulated diffuse reflectance images, we achieved a quantification speed of 266, 174, and 74 frames per second for three image sizes 512×512, 1024×1024, and 2048×2048 pixels, respectively. Quantification of tissue perfusion properties was highly accurate with only 3.5% and 2.5% error for total hemoglobin and oxygen saturation quantification, respectively. The two-stage LUT has the potential to be adopted in existing SFDI applications to enable real-time imaging capability of tissue hemodynamics.
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7
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Sun T, Zhu C. Empirical method for rapid quantification of intrinsic fluorescence signals of key metabolic probes from optical spectra measured on tissue-mimicking turbid medium. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210046R. [PMID: 33893727 PMCID: PMC8062794 DOI: 10.1117/1.jbo.26.4.045001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/07/2021] [Indexed: 05/27/2023]
Abstract
SIGNIFICANCE Optical fluorescence spectroscopy technique has been explored extensively to quantify both glucose uptake and mitochondrial metabolism with proper fluorescent probes in small tumor models in vivo. However, it remains a great challenge to rapidly quantify the intrinsic metabolic fluorophores from the optically measured fluorescence spectra that contain significant distortions due to tissue absorption and scattering. AIM To enable rapid spectral data processing and quantify the in vivo metabolic parameters in real-time, we present an empirical ratio-metric method for rapid fluorescence spectra attenuation correction with high accuracy. APPROACH A first-order approximation of intrinsic fluorescence spectra can be obtained by dividing the fluorescence spectra by diffuse reflectance spectra with some variable powers. We further developed this approximation for rapid extraction of intrinsic key metabolic probes (2-NBDG for glucose uptake and TMRE for mitochondrial function) by dividing the distorted fluorescence spectra by diffuse reflectance intensities recorded at excitation and emission peak with a pair of system-dependent powers. Tissue-mimicking phantom studies were conducted to evaluate the method. RESULTS The tissue-mimicking phantom studies demonstrated that our empirical method could quantify the key intrinsic metabolic probes in near real-time with an average percent error of ∼5 % . CONCLUSIONS An empirical method was demonstrated for rapid quantification of key metabolic probes from fluorescence spectra measured on a tissue-mimicking turbid medium. The proposed method will potentially facilitate real-time monitoring of key metabolic parameters of tumor models in vivo using optical spectroscopy, which will significantly advance translational cancer research.
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Affiliation(s)
- Tengfei Sun
- University of Kentucky, Department of Biomedical Engineering, Lexington, Kentucky, United States
| | - Caigang Zhu
- University of Kentucky, Department of Biomedical Engineering, Lexington, Kentucky, United States
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8
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Wang R, Alvarez DA, Crouch BT, Pilani A, Lam C, Zhu C, Hughes P, Katz D, Haystead T, Ramanujam N. Understanding the sources of errors in ex vivo Hsp90 molecular imaging for rapid-on-site breast cancer diagnosis. BIOMEDICAL OPTICS EXPRESS 2021; 12:2299-2311. [PMID: 33996230 PMCID: PMC8086448 DOI: 10.1364/boe.418818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/26/2021] [Accepted: 03/16/2021] [Indexed: 05/12/2023]
Abstract
Overexpression of heat shock protein 90 (Hsp90) on the surface of breast cancer cells makes it an attractive molecular biomarker for breast cancer diagnosis. Before a ubiquitous diagnostic method can be established, an understanding of the systematic errors in Hsp90-based imaging is essential. In this study, we investigated three factors that may influence the sensitivity of ex vivo Hsp90 molecular imaging: time-dependent tissue viability, nonspecific diffusion of an Hsp90 specific probe (HS-27), and contact-based imaging. These three factors will be important considerations when designing any diagnostic imaging strategy based on fluorescence imaging of a molecular target on tissue samples.
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Affiliation(s)
- Roujia Wang
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Daniel A. Alvarez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Brian T. Crouch
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Aditi Pilani
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Christopher Lam
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Caigang Zhu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
- Currently at Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky, 40506, USA
| | - Philip Hughes
- Department of Pharmacology and Cancer Biology, School of Medicine, Duke University, Durham, North Carolina 27708, USA
| | - David Katz
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Timothy Haystead
- Department of Pharmacology and Cancer Biology, School of Medicine, Duke University, Durham, North Carolina 27708, USA
| | - Nirmala Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
- Department of Pharmacology and Cancer Biology, School of Medicine, Duke University, Durham, North Carolina 27708, USA
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9
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Carrico E, Sun T, Zhu C. Numerical investigation of depth-sensitive diffuse reflectance and fluorescence measurements on murine subcutaneous tissue with growing solid tumors. BIOMEDICAL OPTICS EXPRESS 2020; 11:6311-6323. [PMID: 33282492 PMCID: PMC7687953 DOI: 10.1364/boe.405321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/24/2020] [Accepted: 10/05/2020] [Indexed: 05/08/2023]
Abstract
In most biomedical optical spectroscopy platforms, a fiber-probe consisting of single or multiple illumination and collection fibers was commonly used for the delivery of illuminating light and the collection of emitted light. Typically, the signals from all collection fibers were combined and then sampled to characterize tissue samples. Such simple averaged optical measurements may induce significant errors for in vivo tumor characterization, especially in longitudinal studies where the tumor size and location vary with tumor stages. In this study, we utilized the Monte Carlo technique to optimize the fiber-probe geometries of a spectroscopy platform to enable tumor-sensitive diffuse reflectance and fluorescence measurements on murine subcutaneous tissues with growing solid tumors that have different sizes and depths. Our data showed that depth-sensitive techniques offer improved sensitivity in tumor detection compared to the simple averaged approach in both reflectance and fluorescence measurements. Through the numerical studies, we optimized the source-detector distances, fiber diameters, and numerical apertures for sensitive measurement of small solid tumors with varying size and depth buried in murine subcutaneous tissues. Our study will advance the design of a fiber-probe in an optical spectroscopy system that can be used for longitudinal tumor metabolism and vasculature monitoring.
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Affiliation(s)
- Evan Carrico
- Department of Electrical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Tengfei Sun
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Caigang Zhu
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
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10
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Zhu C, Li M, Vincent T, Martin HL, Crouch BT, Martinez AF, Madonna MC, Palmer GM, Dewhirst MW, Ramanujam N. Simultaneous in vivo optical quantification of key metabolic and vascular endpoints reveals tumor metabolic diversity in murine breast tumor models. JOURNAL OF BIOPHOTONICS 2019; 12:e201800372. [PMID: 30565420 PMCID: PMC8744479 DOI: 10.1002/jbio.201800372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/15/2018] [Accepted: 12/16/2018] [Indexed: 05/24/2023]
Abstract
Therapeutically exploiting vascular and metabolic endpoints becomes critical to translational cancer studies because altered vascularity and deregulated metabolism are two important cancer hallmarks. The metabolic and vascular phenotypes of three sibling breast tumor lines with different metastatic potential are investigated in vivo with a newly developed quantitative spectroscopy system. All tumor lines have different metabolic and vascular characteristics compared to normal tissues, and there are strong positive correlations between metabolic (glucose uptake and mitochondrial membrane potential) and vascular (oxygen saturations and hemoglobin concentrations) parameters for metastatic (4T1) tumors but not for micrometastatic (4T07) and nonmetastatic (67NR) tumors. A longitudinal study shows that both vascular and metabolic endpoints of 4T1 tumors increased up to a specific tumor size threshold beyond which these parameters decreased. The synchronous changes between metabolic and vascular parameters, along with the strong positive correlations between these endpoints suggest that 4T1 tumors rely on strong oxidative phosphorylation in addition to glycolysis. This study illustrates the great potential of our optical technique to provide valuable dynamic information about the interplay between the metabolic and vascular status of tumors, with important implications for translational cancer investigations.
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Affiliation(s)
- Caigang Zhu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Martin Li
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Thomas Vincent
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Hannah L Martin
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Brian T Crouch
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Amy F Martinez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
- Office of Research, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Megan C Madonna
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Gregory M Palmer
- Department of Radiation Oncology, Duke University, Durham, North Carolina
| | - Mark W Dewhirst
- Department of Radiation Oncology, Duke University, Durham, North Carolina
| | - Nimmi Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
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11
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Madonna MC, Fox DB, Crouch BT, Lee J, Zhu C, Martinez AF, Alvarez JV, Ramanujam N. Optical Imaging of Glucose Uptake and Mitochondrial Membrane Potential to Characterize Her2 Breast Tumor Metabolic Phenotypes. Mol Cancer Res 2019; 17:1545-1555. [PMID: 30902832 DOI: 10.1158/1541-7786.mcr-18-0618] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/09/2018] [Accepted: 03/19/2019] [Indexed: 11/16/2022]
Abstract
With the large number of women diagnosed and treated for breast cancer each year, the importance of studying recurrence has become evident due to most deaths from breast cancer resulting from tumor recurrence following therapy. To mitigate this, cellular and molecular pathways used by residual disease prior to recurrence must be studied. An altered metabolism has long been considered a hallmark of cancer, and several recent studies have gone further to report metabolic dysfunction and alterations as key to understanding the underlying behavior of dormant and recurrent cancer cells. Our group has used two probes, 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl) amino]-2-deoxyglucose (2-NBDG) and tetramethyl rhodamine ethyl ester (TMRE), to image glucose uptake and mitochondrial membrane potential, respectively, to report changes in metabolism between primary tumors, regression, residual disease, and after regrowth in genetically engineered mouse (GEM)-derived mammospheres. Imaging revealed unique metabolic phenotypes across the stages of tumor development. Although primary mammospheres overexpressing Her2 maintained increased glucose uptake ("Warburg effect"), after Her2 downregulation, during regression and residual disease, mammospheres appeared to switch to oxidative phosphorylation. Interestingly, in mammospheres where Her2 overexpression was turned back on to model recurrence, glucose uptake was lowest, indicating a potential change in substrate preference following the reactivation of Her2, reeliciting growth. Our findings highlight the importance of imaging metabolic adaptions to gain insight into the fundamental behaviors of residual and recurrent disease. IMPLICATIONS: This study demonstrates these functional fluorescent probes' ability to report metabolic adaptations during primary tumor growth, regression, residual disease, and regrowth in Her2 breast tumors.
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Affiliation(s)
- Megan C Madonna
- Department of Biomedical Engineering, Duke University, Durham, North Carolina.
| | - Douglas B Fox
- Department of Pharmacology & Cancer Biology, School of Medicine, Duke University, Durham, North Carolina
| | - Brian T Crouch
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Jihong Lee
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Caigang Zhu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Amy F Martinez
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - James V Alvarez
- Department of Pharmacology & Cancer Biology, School of Medicine, Duke University, Durham, North Carolina
| | - Nirmala Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, North Carolina.,Department of Pharmacology & Cancer Biology, School of Medicine, Duke University, Durham, North Carolina
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12
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Zhu C, Martin HL, Crouch BT, Martinez AF, Li M, Palmer GM, Dewhirst MW, Ramanujam N. Near-simultaneous quantification of glucose uptake, mitochondrial membrane potential, and vascular parameters in murine flank tumors using quantitative diffuse reflectance and fluorescence spectroscopy. BIOMEDICAL OPTICS EXPRESS 2018; 9:3399-3412. [PMID: 29984105 PMCID: PMC6033552 DOI: 10.1364/boe.9.003399] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/14/2018] [Accepted: 06/18/2018] [Indexed: 05/24/2023]
Abstract
The shifting metabolic landscape of aggressive tumors, with fluctuating oxygenation conditions and temporal changes in glycolysis and mitochondrial metabolism, is a critical phenomenon to study in order to understand negative treatment outcomes. Recently, we have demonstrated near-simultaneous optical imaging of mitochondrial membrane potential (MMP) and glucose uptake in non-tumor window chambers, using the fluorescent probes tetramethylrhodamine ethyl ester (TMRE) and 2-N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG). Here, we demonstrate a complementary technique to perform near-simultaneous in vivo optical spectroscopy of tissue vascular parameters, glucose uptake, and MMP in a solid tumor model that is most often used for therapeutic studies. Our study demonstrates the potential of optical spectroscopy as an effective tool to quantify the vascular and metabolic characteristics of a tumor, which is an important step towards understanding the mechanisms underlying cancer progression, metastasis, and resistance to therapies.
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Affiliation(s)
- Caigang Zhu
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Hannah L. Martin
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Brian T. Crouch
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Amy F. Martinez
- Currently with Office of Research, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Martin Li
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Gregory M. Palmer
- Department of Radiation Oncology, Duke University, Durham, NC 27710, USA
| | - Mark W. Dewhirst
- Department of Radiation Oncology, Duke University, Durham, NC 27710, USA
| | - Nimmi Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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13
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In-vivo topical mucosal delivery of a fluorescent deoxy-glucose delineates neoplasia from normal in a preclinical model of oral epithelial neoplasia. Sci Rep 2018; 8:9760. [PMID: 29950704 PMCID: PMC6021424 DOI: 10.1038/s41598-018-28014-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 06/14/2018] [Indexed: 12/28/2022] Open
Abstract
Metabolic imaging of oral cavity mucosal surfaces could benefit early detection of oral squamous cell carcinoma (OSCC) and oral epithelial dysplasia (OED). Fluorescent deoxy-glucose agents provide contrast for glucose metabolism similar to 18FDG-PET imaging and allow use of optical imaging, which provides high resolution and lower potential cost. However, in-vivo topical mucosal delivery of fluorescent deoxy-glucose agents without injection or tissue resection has not been shown. We introduce in-vivo optical imaging of neoplasia following mucosal delivery of 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose (2-NBDG) in an OSCC/OED hamster model and demonstrate uptake into epithelium across the mucosal surface without injection or disrupting the epithelium. 2-NBDG fluorescence intensity following 30-minutes topical application was 6-fold and 4-fold higher in OSCC and OED, respectively, compared to normal mucosa. Receiver operator characteristic analysis show 83% sensitivity and 73% specificity for detection of neoplasia vs benign (normal and inflammation). Faster 2-NBDG fluorescence temporal decay in neoplasia indicated higher uptake and glucose metabolic rate than normal mucosa. Mucosal delivery of 2-NBDG by topical application to the in-vivo oral surface is feasible and delineates neoplasia from normal mucosa, providing in-vivo noninvasive molecular imaging of dysregulated glucose metabolism, which could benefit preclinical studies of carcinogenesis or be developed for use in early detection.
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14
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Greening GJ, Miller KP, Spainhour CR, Cato MD, Muldoon TJ. Effects of isoflurane anesthesia on physiological parameters in murine subcutaneous tumor allografts measured via diffuse reflectance spectroscopy. BIOMEDICAL OPTICS EXPRESS 2018; 9:2871-2886. [PMID: 30258696 PMCID: PMC6154201 DOI: 10.1364/boe.9.002871] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/21/2018] [Accepted: 05/23/2018] [Indexed: 05/03/2023]
Abstract
Diffuse reflectance spectroscopy (DRS) has been used in murine studies to quantify tumor perfusion and therapeutic response. These studies frequently use inhaled isoflurane anesthesia, which depresses the respiration rate and results in the desaturation of arterial oxygen saturation, potentially affecting tissue physiological parameters. However, there have been no controlled studies quantifying the effect of isoflurane anesthesia on DRS-derived physiological parameters of murine tissue. The goal of this study was to perform DRS on Balb/c mouse (n = 10) tissue under various anesthesia conditions to quantify effects on tissue physiological parameters, including total hemoglobin concentration, tissue oxygen saturation, oxyhemoglobin and reduced scattering coefficient. Two independent variables were manipulated including metabolic gas type (pure oxygen vs. medical air) and isoflurane concentration (1.5 to 4.0%). The 1.5% isoflurane and 1 L/min oxygen condition most closely mimicked a no-anesthesia condition with oxyhemoglobin concentration within 89% ± 19% of control. The time-dependent effects of isoflurane anesthesia were tested, revealing that anesthetic induction with 4.0% isoflurane can affect DRS-derived physiological parameters up to 20 minutes post-induction. Finally, spectroscopy with and without isoflurane anesthesia was compared for colon tumor Balb/c-CT26 allografts (n = 5) as a representative model of subcutaneous murine tumor allografts. Overall, isoflurane anesthesia yielded experimentally-induced depressed oxyhemoglobin, and this depression was both concentration and time dependent. Investigators should understand the dynamic effects of isoflurane on tissue physiological parameters measured by DRS. These results may guide investigators in eliminating, limiting, or managing anesthesia-induced physiological changes in DRS studies in mouse models.
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Affiliation(s)
- Gage J. Greening
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Kathryn P. Miller
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Caroline R. Spainhour
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Mattison D. Cato
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Timothy J. Muldoon
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
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15
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Martinez AF, McCachren SS, Lee M, Murphy HA, Zhu C, Crouch BT, Martin HL, Erkanli A, Rajaram N, Ashcraft KA, Fontanella AN, Dewhirst MW, Ramanujam N. Metaboloptics: Visualization of the tumor functional landscape via metabolic and vascular imaging. Sci Rep 2018. [PMID: 29520098 PMCID: PMC5843602 DOI: 10.1038/s41598-018-22480-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Many cancers adeptly modulate metabolism to thrive in fluctuating oxygen conditions; however, current tools fail to image metabolic and vascular endpoints at spatial resolutions needed to visualize these adaptations in vivo. We demonstrate a high-resolution intravital microscopy technique to quantify glucose uptake, mitochondrial membrane potential (MMP), and SO2 to characterize the in vivo phentoypes of three distinct murine breast cancer lines. Tetramethyl rhodamine, ethyl ester (TMRE) was thoroughly validated to report on MMP in normal and tumor-bearing mice. Imaging MMP or glucose uptake together with vascular endpoints revealed that metastatic 4T1 tumors maintained increased glucose uptake across all SO2 (“Warburg effect”), and also showed increased MMP relative to normal tissue. Non-metastatic 67NR and 4T07 tumor lines both displayed increased MMP, but comparable glucose uptake, relative to normal tissue. The 4T1 peritumoral areas also showed a significant glycolytic shift relative to the tumor regions. During a hypoxic stress test, 4T1 tumors showed significant increases in MMP with corresponding significant drops in SO2, indicative of intensified mitochondrial metabolism. Conversely, 4T07 and 67NR tumors shifted toward glycolysis during hypoxia. Our findings underscore the importance of imaging metabolic endpoints within the context of a living microenvironment to gain insight into a tumor’s adaptive behavior.
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Affiliation(s)
- Amy F Martinez
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
| | | | - Marianne Lee
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Helen A Murphy
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Caigang Zhu
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Brian T Crouch
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Hannah L Martin
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Alaattin Erkanli
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC, USA
| | | | | | | | | | - Nirmala Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
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16
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Durkee MS, Nash LD, Nooshabadi F, Cirillo JD, Maitland DJ, Maitland KC. Fabrication and Characterization of Optical Tissue Phantoms Containing Macrostructure. J Vis Exp 2018. [PMID: 29553502 DOI: 10.3791/57031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The rapid development of new optical imaging techniques is dependent on the availability of low-cost, customizable, and easily reproducible standards. By replicating the imaging environment, costly animal experiments to validate a technique may be circumvented. Predicting and optimizing the performance of in vivo and ex vivo imaging techniques requires testing on samples that are optically similar to tissues of interest. Tissue-mimicking optical phantoms provide a standard for evaluation, characterization, or calibration of an optical system. Homogenous polymer optical tissue phantoms are widely used to mimic the optical properties of a specific tissue type within a narrow spectral range. Layered tissues, such as the epidermis and dermis, can be mimicked by simply stacking these homogenous slab phantoms. However, many in vivo imaging techniques are applied to more spatially complex tissue where three dimensional structures, such as blood vessels, airways, or tissue defects, can affect the performance of the imaging system. This protocol describes the fabrication of a tissue-mimicking phantom that incorporates three-dimensional structural complexity using material with optical properties of tissue. Look-up tables provide India ink and titanium dioxide recipes for optical absorption and scattering targets. Methods to characterize and tune the material optical properties are described. The phantom fabrication detailed in this article has an internal branching mock airway void; however, the technique can be broadly applied to other tissue or organ structures.
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Affiliation(s)
| | - Landon D Nash
- Department of Biomedical Engineering, Texas A&M University
| | | | - Jeffrey D Cirillo
- Deparment of Molecular Pathogenesis and Immunology, Texas A&M College of Medicine
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17
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Zhu C, Martinez AF, Martin HL, Li M, Crouch BT, Carlson DA, Haystead TAJ, Ramanujam N. Near-simultaneous intravital microscopy of glucose uptake and mitochondrial membrane potential, key endpoints that reflect major metabolic axes in cancer. Sci Rep 2017; 7:13772. [PMID: 29062013 PMCID: PMC5653871 DOI: 10.1038/s41598-017-14226-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 10/06/2017] [Indexed: 12/19/2022] Open
Abstract
While the demand for metabolic imaging has increased in recent years, simultaneous in vivo measurement of multiple metabolic endpoints remains challenging. Here we report on a novel technique that provides in vivo high-resolution simultaneous imaging of glucose uptake and mitochondrial metabolism within a dynamic tissue microenvironment. Two indicators were leveraged; 2-[N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG) reports on glucose uptake and Tetramethylrhodamine ethyl ester (TMRE) reports on mitochondrial membrane potential. Although we demonstrated that there was neither optical nor chemical crosstalk between 2-NBDG and TMRE, TMRE uptake was significantly inhibited by simultaneous injection with 2-NBDG in vivo. A staggered delivery scheme of the two agents (TMRE injection was followed by 2-NBDG injection after a 10-minute delay) permitted near-simultaneous in vivo microscopy of 2-NBDG and TMRE at the same tissue site by mitigating the interference of 2-NBDG with normal glucose usage. The staggered delivery strategy was evaluated under both normoxic and hypoxic conditions in normal tissues as well as in a murine breast cancer model. The results were consistent with those expected for independent imaging of 2-NBDG and TMRE. This optical imaging technique allows for monitoring of key metabolic endpoints with the unique benefit of repeated, non-destructive imaging within an intact microenvironment.
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Affiliation(s)
- Caigang Zhu
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Amy F Martinez
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Hannah L Martin
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Martin Li
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Brian T Crouch
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - David A Carlson
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, 27710, USA
| | - Timothy A J Haystead
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, 27710, USA
| | - Nimmi Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
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18
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Morris BA, Burkel B, Ponik SM, Fan J, Condeelis JS, Aguirre-Ghiso JA, Castracane J, Denu JM, Keely PJ. Collagen Matrix Density Drives the Metabolic Shift in Breast Cancer Cells. EBioMedicine 2016; 13:146-156. [PMID: 27743905 PMCID: PMC5264313 DOI: 10.1016/j.ebiom.2016.10.012] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/06/2016] [Accepted: 10/07/2016] [Indexed: 12/19/2022] Open
Abstract
Increased breast density attributed to collagen I deposition is associated with a 4-6 fold increased risk of developing breast cancer. Here, we assessed cellular metabolic reprogramming of mammary carcinoma cells in response to increased collagen matrix density using an in vitro 3D model. Our initial observations demonstrated changes in functional metabolism in both normal mammary epithelial cells and mammary carcinoma cells in response to changes in matrix density. Further, mammary carcinoma cells grown in high density collagen matrices displayed decreased oxygen consumption and glucose metabolism via the tricarboxylic acid (TCA) cycle compared to cells cultured in low density matrices. Despite decreased glucose entry into the TCA cycle, levels of glucose uptake, cell viability, and ROS were not different between high and low density matrices. Interestingly, under high density conditions the contribution of glutamine as a fuel source to drive the TCA cycle was significantly enhanced. These alterations in functional metabolism mirrored significant changes in the expression of metabolic genes involved in glycolysis, oxidative phosphorylation, and the serine synthesis pathway. This study highlights the broad importance of the collagen microenvironment to cellular expression profiles, and shows that changes in density of the collagen microenvironment can modulate metabolic shifts of cancer cells.
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Affiliation(s)
- Brett A Morris
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, United States
| | - Brian Burkel
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, United States; Department of Biomedical Engineering, University of Wisconsin-Madison, United States
| | - Suzanne M Ponik
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, United States.
| | - Jing Fan
- Wisconsin Institute for Discovery and Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, United States; Morgridge Institute for Research, Madison, WI, United States
| | - John S Condeelis
- Dept. of Anatomy & Structural Biology, Albert Einstein College of Medicine, United States
| | - Julio A Aguirre-Ghiso
- Division of Hematology and Oncology, Department of Medicine, Tisch Cancer Institute, Mount Sinai School of Medicine, United States; Department of Otolaryngology, Tisch Cancer Institute, Mount Sinai School of Medicine, United States; Department of Oncological Sciences, Tisch Cancer Institute, Mount Sinai School of Medicine, United States; Black Family Stem Cell Institute, Mount Sinai School of Medicine, United States
| | - James Castracane
- Colleges of Nanoscale Science and Engineering (CNSE), SUNY Polytechnic Institute, United States
| | - John M Denu
- Wisconsin Institute for Discovery and Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, United States; Morgridge Institute for Research, Madison, WI, United States
| | - Patricia J Keely
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, United States; Paul C. Carbone Cancer Center, University of Wisconsin-Madison, United States
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19
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Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues. Nat Commun 2016; 7:12121. [PMID: 27358000 PMCID: PMC4931322 DOI: 10.1038/ncomms12121] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/31/2016] [Indexed: 01/09/2023] Open
Abstract
Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.
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