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Liu J, Shelton EL, Crescenzi R, Colvin DC, Kirabo A, Zhong J, Delpire EJ, Yang HC, Kon V. Kidney Injury Causes Accumulation of Renal Sodium That Modulates Renal Lymphatic Dynamics. Int J Mol Sci 2022; 23:ijms23031428. [PMID: 35163352 PMCID: PMC8836121 DOI: 10.3390/ijms23031428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 01/02/2023] Open
Abstract
Lymphatic vessels are highly responsive to changes in the interstitial environment. Previously, we showed renal lymphatics express the Na-K-2Cl cotransporter. Since interstitial sodium retention is a hallmark of proteinuric injury, we examined whether renal sodium affects NKCC1 expression and the dynamic pumping function of renal lymphatic vessels. Puromycin aminonucleoside (PAN)-injected rats served as a model of proteinuric kidney injury. Sodium 23Na/1H-MRI was used to measure renal sodium and water content in live animals. Renal lymph, which reflects the interstitial composition, was collected, and the sodium analyzed. The contractile dynamics of isolated renal lymphatic vessels were studied in a perfusion chamber. Cultured lymphatic endothelial cells (LECs) were used to assess direct sodium effects on NKCC1. MRI showed elevation in renal sodium and water in PAN. In addition, renal lymph contained higher sodium, although the plasma sodium showed no difference between PAN and controls. High sodium decreased contractility of renal collecting lymphatic vessels. In LECs, high sodium reduced phosphorylated NKCC1 and SPAK, an upstream activating kinase of NKCC1, and eNOS, a downstream effector of lymphatic contractility. The NKCC1 inhibitor furosemide showed a weaker effect on ejection fraction in isolated renal lymphatics of PAN vs controls. High sodium within the renal interstitium following proteinuric injury is associated with impaired renal lymphatic pumping that may, in part, involve the SPAK-NKCC1-eNOS pathway, which may contribute to sodium retention and reduce lymphatic responsiveness to furosemide. We propose that this lymphatic vessel dysfunction is a novel mechanism of impaired interstitial clearance and edema in proteinuric kidney disease.
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Affiliation(s)
- Jing Liu
- Department of Nephrology, Tongji University School of Medicine, Shanghai 200070, China;
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Elaine L. Shelton
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - Rachelle Crescenzi
- Department of Radiology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (R.C.); (D.C.C.)
| | - Daniel C. Colvin
- Department of Radiology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (R.C.); (D.C.C.)
| | - Annet Kirabo
- Department of Medicine, Division of Clinal Pharmacology and Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (A.K.); (J.Z.)
| | - Jianyong Zhong
- Department of Medicine, Division of Clinal Pharmacology and Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (A.K.); (J.Z.)
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - Eric J. Delpire
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hai-Chun Yang
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Correspondence: (H.-C.Y.); (V.K.); Tel.: +1-615-343-0110 (H.-C.Y.); +1-615-322-7416 (V.K.)
| | - Valentina Kon
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Correspondence: (H.-C.Y.); (V.K.); Tel.: +1-615-343-0110 (H.-C.Y.); +1-615-322-7416 (V.K.)
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Wang F, Otsuka T, Takahashi K, Narui C, Colvin DC, Harris RC, Takahashi T, Gore JC. Renal tubular dilation and fibrosis after unilateral ureter obstruction revealed by relaxometry and spin-lock exchange MRI. NMR Biomed 2021; 34:e4539. [PMID: 33963778 PMCID: PMC10805126 DOI: 10.1002/nbm.4539] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
We evaluated the use of quantitative MRI relaxometry, including the dispersion of spin-lock relaxation with different locking fields, for detecting and assessing tubular dilation and fibrosis in a mouse model of unilateral ureter obstruction (UUO). C57BL/6 J and BALB/c mice that exhibit different levels of tubular dilation and renal fibrosis after UUO were subjected to MR imaging at 7 T. Mice were imaged before UUO surgery, and at 5, 10 and 15 days after surgery. We acquired maps of relaxation rates and fit the dispersion of spin-lock relaxation rates R1ρ at different locking fields (frequencies) to a model of exchanging water pools, and assessed the sensitivity of the derived quantities for detecting tubular dilation and fibrosis in kidney. Histological scores for tubular dilation and fibrosis, based on luminal space and positive fibrotic areas in sections, were obtained for comparison. Histology detected extensive tubular dilation and mild to moderate fibrosis in the UUO kidneys, in which enlargement of luminal space, deposition of collagen, and reductions in capillary density were observed in the cortex and outer stripe of the outer medulla. Relaxation rates R1 , R2 and R1ρ clearly decreased in these regions of UUO kidneys longitudinally. While R1 showed the highest detectability to tubular dilation and overall changes in UUO kidneys, Sρ , a parameter derived from R1ρ dispersion data, showed the highest correlation with renal fibrosis in UUO. While relaxation parameters are sensitive to tubular dilation in UUO kidneys, Sρ depends primarily on the average exchange rate between water and other chemically shifted resonances such as hydroxyls and amides, and provides additional specific information for evaluating fibrosis in kidney disease.
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Affiliation(s)
- Feng Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center
- Vanderbilt O’Brien Kidney Research Center, Vanderbilt University Medical Center
| | - Tadashi Otsuka
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center
| | - Keiko Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center
| | - Chikage Narui
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center
| | - Daniel C. Colvin
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center
| | - Raymond C. Harris
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center
- Vanderbilt O’Brien Kidney Research Center, Vanderbilt University Medical Center
| | - Takamune Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center
- Vanderbilt O’Brien Kidney Research Center, Vanderbilt University Medical Center
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center
- Department of Biomedical Engineering, Vanderbilt University Nashville, TN 37232
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Wang F, Colvin DC, Wang S, Li H, Zu Z, Harris RC, Zhang MZ, Gore JC. Spin-lock relaxation rate dispersion reveals spatiotemporal changes associated with tubulointerstitial fibrosis in murine kidney. Magn Reson Med 2020; 84:2074-2087. [PMID: 32141646 DOI: 10.1002/mrm.28230] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 01/09/2020] [Accepted: 02/04/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE To develop and evaluate a reliable non-invasive means for assessing the severity and progression of fibrosis in kidneys. We used spin-lock MR imaging with different locking fields to detect and characterize progressive renal fibrosis in an hHB-EGFTg/Tg mouse model. METHODS Male hHB-EGFTg/Tg mice, a well-established model of progressive fibrosis, and age-matched normal wild type (WT) mice, were imaged at 7T at ages 5-7, 11-13, and 30-40 weeks. Spin-lock relaxation rates R1 ρ were measured at different locking fields (frequencies) and the resultant dispersion curves were fit to a model of exchanging water pools. The obtained MRI parameters were evaluated as potential indicators of tubulointerstitial fibrosis in kidney. Histological examinations of renal fibrosis were also carried out post-mortem after MRI. RESULTS Histology detected extensive fibrosis in the hHB-EGFTg/Tg mice, in which collagen deposition and reductions in capillary density were observed in the fibrotic regions of kidneys. R2 and R1 ρ values at different spin-lock powers clearly dropped in the fibrotic region as fibrosis progressed. There was less variation in the asymptotic locking field relaxation rate R 1 ρ ∞ between the groups. The exchange parameter Sρ and the inflection frequency ωinfl changed by larger factors. CONCLUSION Both Sρ and ωinfl depend primarily on the average exchange rate between water and other chemically shifted resonances such as hydroxyls and amides. Spin-lock relaxation rate dispersion, rather than single measurements of relaxation rates, provides more comprehensive and specific information on spatiotemporal changes associated with tubulointerstitial fibrosis in murine kidney.
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Affiliation(s)
- Feng Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Daniel C Colvin
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Suwan Wang
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Hua Li
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Raymond C Harris
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ming-Zhi Zhang
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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Cassat JE, Moore JL, Wilson KJ, Stark Z, Prentice BM, Van de Plas R, Perry WJ, Zhang Y, Virostko J, Colvin DC, Rose KL, Judd AM, Reyzer ML, Spraggins JM, Grunenwald CM, Gore JC, Caprioli RM, Skaar EP. Integrated molecular imaging reveals tissue heterogeneity driving host-pathogen interactions. Sci Transl Med 2019. [PMID: 29540616 DOI: 10.1126/scitranslmed.aan6361] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diseases are characterized by distinct changes in tissue molecular distribution. Molecular analysis of intact tissues traditionally requires preexisting knowledge of, and reagents for, the targets of interest. Conversely, label-free discovery of disease-associated tissue analytes requires destructive processing for downstream identification platforms. Tissue-based analyses therefore sacrifice discovery to gain spatial distribution of known targets or sacrifice tissue architecture for discovery of unknown targets. To overcome these obstacles, we developed a multimodality imaging platform for discovery-based molecular histology. We apply this platform to a model of disseminated infection triggered by the pathogen Staphylococcus aureus, leading to the discovery of infection-associated alterations in the distribution and abundance of proteins and elements in tissue in mice. These data provide an unbiased, three-dimensional analysis of how disease affects the molecular architecture of complex tissues, enable culture-free diagnosis of infection through imaging-based detection of bacterial and host analytes, and reveal molecular heterogeneity at the host-pathogen interface.
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Affiliation(s)
- James E Cassat
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jessica L Moore
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Kevin J Wilson
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232, USA
| | - Zach Stark
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232, USA
| | - Boone M Prentice
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Raf Van de Plas
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA.,Delft Center for Systems and Control, Delft University of Technology, Delft, Netherlands
| | - William J Perry
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Yaofang Zhang
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - John Virostko
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232, USA
| | - Daniel C Colvin
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232, USA
| | - Kristie L Rose
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Audra M Judd
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Michelle L Reyzer
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Jeffrey M Spraggins
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Caroline M Grunenwald
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - John C Gore
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA.,Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232, USA.,Departments of Radiology and Radiologic Sciences, Biomedical Engineering, Molecular Physiology and Biophysics, and Physics and Astronomy, Vanderbilt University, Nashville, TN 37232, USA
| | - Richard M Caprioli
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN 37232, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA.,Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA. .,U.S. Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, 37232, USA
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5
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Tantawy MN, Charles Manning H, Peterson TE, Colvin DC, Gore JC, Lu W, Chen Z, Chad Quarles C. Translocator Protein PET Imaging in a Preclinical Prostate Cancer Model. Mol Imaging Biol 2019; 20:200-204. [PMID: 28822038 DOI: 10.1007/s11307-017-1113-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE The identification and targeting of biomarkers specific to prostate cancer (PCa) could improve its detection. Given the high expression of translocator protein (TSPO) in PCa, we investigated the use of [18F]VUIIS1008 (a novel TSPO-targeting radioligand) coupled with positron emission tomography (PET) to identify PCa in mice and to characterize their TSPO uptake. PROCEDURES Ptenpc-/-, Trp53pc-/- prostate cancer-bearing mice (n = 9, 4-6 months old) were imaged in a 7T MRI scanner for lesion localization. Within 24 h, the mice were imaged using a microPET scanner for 60 min in dynamic mode following a retro-orbital injection of ~ 18 MBq [18F]VUIIS1008. Following imaging, tumors were harvested and stained with a TSPO antibody. Regions of interest (ROIs) were drawn around the tumor and muscle (hind limb) in the PET images. Time-activity curves (TACs) were recorded over the duration of the scan for each ROI. The mean activity concentrations between 40 and 60 min post radiotracer administration between tumor and muscle were compared. RESULTS Tumor presence was confirmed by visual inspection of the MR images. The uptake of [18F]VUIIS1008 in the tumors was significantly higher (p < 0.05) than that in the muscle, where the percent injected dose per unit volume for tumor was 7.1 ± 1.6 % ID/ml and that of muscle was < 1 % ID/ml. In addition, positive TSPO expression was observed in tumor tissue analysis. CONCLUSIONS The foregoing preliminary data suggest that TSPO may be a useful biomarker of PCa. Therefore, using TSPO-targeting PET ligands, such as [18F]VUIIS1008, may improve PCa detectability and characterization.
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Affiliation(s)
- Mohammed N Tantawy
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical Center, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - H Charles Manning
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical Center, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.,Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.,Program in Chemical and Physical Biology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Todd E Peterson
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical Center, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Daniel C Colvin
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical Center, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical Center, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Wenfu Lu
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Zhenbang Chen
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN, 37208, USA
| | - C Chad Quarles
- Imaging Research, Barrow Neurological Institute, 350 W Thomas Rd, Phoenix, AZ, 85013, USA.
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Amato KR, Wang S, Tan L, Hastings AK, Song W, Lovly CM, Meador CB, Ye F, Lu P, Balko JM, Colvin DC, Cates JM, Pao W, Gray NS, Chen J. EPHA2 Blockade Overcomes Acquired Resistance to EGFR Kinase Inhibitors in Lung Cancer. Cancer Res 2016; 76:305-18. [PMID: 26744526 PMCID: PMC4715957 DOI: 10.1158/0008-5472.can-15-0717] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 10/14/2015] [Indexed: 01/18/2023]
Abstract
Despite the success of treating EGFR-mutant lung cancer patients with EGFR tyrosine kinase inhibitors (TKI), all patients eventually acquire resistance to these therapies. Although various resistance mechanisms have been described, there are currently no FDA-approved therapies that target alternative mechanisms to treat lung tumors with acquired resistance to first-line EGFR TKI agents. Here we found that EPHA2 is overexpressed in EGFR TKI-resistant tumor cells. Loss of EPHA2 reduced the viability of erlotinib-resistant tumor cells harboring EGFR(T790M) mutations in vitro and inhibited tumor growth and progression in an inducible EGFR(L858R+T790M)-mutant lung cancer model in vivo. Targeting EPHA2 in erlotinib-resistant cells decreased S6K1-mediated phosphorylation of cell death agonist BAD, resulting in reduced tumor cell proliferation and increased apoptosis. Furthermore, pharmacologic inhibition of EPHA2 by the small-molecule inhibitor ALW-II-41-27 decreased both survival and proliferation of erlotinib-resistant tumor cells and inhibited tumor growth in vivo. ALW-II-41-27 was also effective in decreasing viability of cells with acquired resistance to the third-generation EGFR TKI AZD9291. Collectively, these data define a role for EPHA2 in the maintenance of cell survival of TKI-resistant, EGFR-mutant lung cancer and indicate that EPHA2 may serve as a useful therapeutic target in TKI-resistant tumors.
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Affiliation(s)
- Katherine R. Amato
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Shan Wang
- Division of Rheumatology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Li Tan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA,Dana Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Andrew K. Hastings
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Wenqiang Song
- Division of Rheumatology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Christine M. Lovly
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee, USA
| | - Catherine B. Meador
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Fei Ye
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, USA
| | - Pengcheng Lu
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee, USA
| | - Justin M. Balko
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Daniel C. Colvin
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Justin M. Cates
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee, USA
| | - William Pao
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA,Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee, USA
| | - Nathanael S. Gray
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA,Dana Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Jin Chen
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee. Division of Rheumatology and Immunology, Vanderbilt University, Nashville, Tennessee. Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee. Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee. Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, Tennessee.
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7
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Chen H, Qi B, Moore T, Wang F, Colvin DC, Sanjeewa LD, Gore JC, Hwu SJ, Mefford OT, Alexis F, Anker JN. Multifunctional yolk-in-shell nanoparticles for pH-triggered drug release and imaging. Small 2014; 10:3364-70. [PMID: 24753264 PMCID: PMC4474407 DOI: 10.1002/smll.201303769] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 03/23/2014] [Indexed: 05/06/2023]
Abstract
Multifunctional nanoparticles are synthesized for both pH-triggered drug release and imaging with radioluminescence, upconversion luminescent, and magnetic resonance imaging (MRI). The particles have a yolk-in-shell morphology, with a radioluminescent core, an upconverting shell, and a hollow region between the core and shell for loading drugs. They are synthesized by controlled encapsulation of a radioluminescent nanophosphor yolk in a silica shell, partial etching of the yolk in acid, and encapsulation of the silica with an upconverting luminescent shell. Metroxantrone, a chemotherapy drug, was loaded into the hollow space between X-ray phosphor yolk and up-conversion phosphor shell through pores in the shell. To encapsulate the drug and control the release rate, the nanoparticles are coated with pH-responsive biocompatible polyelectrolyte layers of charged hyaluronic acid sodium salt and chitosan. The nanophosphors display bright luminescence under X-ray, blue light (480 nm), and near infrared light (980 nm). They also served as T1 and T2 MRI contrast agents with relaxivities of 3.5 mM(-1) s(-1) (r1 ) and 64 mM(-1) s(-1) (r2 ). These multifunctional nanocapsules have applications in controlled drug delivery and multimodal imaging.
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Affiliation(s)
- Hongyu Chen
- Department of Chemistry, Center for optical materials science and engineering (COMSET), and environmental toxicology program, Clemson University, Clemson SC, 29634, USA
| | - Bin Qi
- Department of Materials Science Engineering, Center for optical materials science and engineering (COMSET), Clemson University, Clemson, SC 29634, USA
| | - Thomas Moore
- Department of Bioengineering, 301 Rhodes Research Center, Clemson, SC 29634, USA
| | - Fenglin Wang
- Department of Chemistry, Center for optical materials science and engineering (COMSET), and environmental toxicology program, Clemson University, Clemson SC, 29634, USA
| | - Daniel C. Colvin
- Vanderbilt University Medical Center, AAA 3107 MCN, Nashville, TN 37232, USA
| | | | - John C. Gore
- Vanderbilt University Medical Center, AAA 3107 MCN, Nashville, TN 37232, USA
| | - Shiou-Jyh Hwu
- Department of Chemistry, Clemson University, Clemson SC, 29634, USA
| | - O. Thompson Mefford
- Department of Materials Science Engineering, Center for optical materials science and engineering (COMSET), Clemson University, Clemson, SC 29634, USA
| | - Frank Alexis
- Department of Bioengineering, 301 Rhodes Research Center, Clemson, SC 29634, USA
| | - Jeffrey N. Anker
- Department of Chemistry, Center for optical materials science and engineering (COMSET), and environmental toxicology program, Clemson University, Clemson SC, 29634, USA
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8
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Amato KR, Wang S, Hastings AK, Youngblood VM, Santapuram PR, Chen H, Cates JM, Colvin DC, Ye F, Brantley-Sieders DM, Cook RS, Tan L, Gray NS, Chen J. Genetic and pharmacologic inhibition of EPHA2 promotes apoptosis in NSCLC. J Clin Invest 2014; 124:2037-49. [PMID: 24713656 DOI: 10.1172/jci72522] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 02/20/2014] [Indexed: 01/15/2023] Open
Abstract
Genome-wide analyses determined previously that the receptor tyrosine kinase (RTK) EPHA2 is commonly overexpressed in non-small cell lung cancers (NSCLCs). EPHA2 overexpression is associated with poor clinical outcomes; therefore, EPHA2 may represent a promising therapeutic target for patients with NSCLC. In support of this hypothesis, here we have shown that targeted disruption of EphA2 in a murine model of aggressive Kras-mutant NSCLC impairs tumor growth. Knockdown of EPHA2 in human NSCLC cell lines reduced cell growth and viability, confirming the epithelial cell autonomous requirements for EPHA2 in NSCLCs. Targeting EPHA2 in NSCLCs decreased S6K1-mediated phosphorylation of cell death agonist BAD and induced apoptosis. Induction of EPHA2 knockdown within established NSCLC tumors in a subcutaneous murine model reduced tumor volume and induced tumor cell death. Furthermore, an ATP-competitive EPHA2 RTK inhibitor, ALW-II-41-27, reduced the number of viable NSCLC cells in a time-dependent and dose-dependent manner in vitro and induced tumor regression in human NSCLC xenografts in vivo. Collectively, these data demonstrate a role for EPHA2 in the maintenance and progression of NSCLCs and provide evidence that ALW-II-41-27 effectively inhibits EPHA2-mediated tumor growth in preclinical models of NSCLC.
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MESH Headings
- Animals
- Apoptosis
- Carcinoma, Non-Small-Cell Lung/drug therapy
- Carcinoma, Non-Small-Cell Lung/enzymology
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/pathology
- Cell Line, Tumor
- Cell Survival
- Heterografts
- Humans
- Lung Neoplasms/drug therapy
- Lung Neoplasms/enzymology
- Lung Neoplasms/genetics
- Lung Neoplasms/pathology
- Mice
- Mice, Knockout
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Neoplasm Transplantation
- Protein Kinase Inhibitors/pharmacology
- Receptor, EphA2/antagonists & inhibitors
- Receptor, EphA2/genetics
- Receptor, EphA2/metabolism
- Ribosomal Protein S6 Kinases, 70-kDa/genetics
- Ribosomal Protein S6 Kinases, 70-kDa/metabolism
- Ribosomal Protein S6 Kinases, 90-kDa/genetics
- Ribosomal Protein S6 Kinases, 90-kDa/metabolism
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9
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Chen H, Qi B, Moore T, Colvin DC, Crawford T, Gore JC, Alexis F, Mefford OT, Anker JN. Synthesis of brightly PEGylated luminescent magnetic upconversion nanophosphors for deep tissue and dual MRI imaging. Small 2014; 10:160-8. [PMID: 23828629 PMCID: PMC4118939 DOI: 10.1002/smll.201300828] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Indexed: 05/21/2023]
Abstract
A method is developed to fabricate monodispersed biocompatible Yb/Er or Yb/Tm doped β-NaGdF4 upconversion phosphors using polyelectrolytes to prevent irreversible particle aggregation during conversion of the precursor, Gd2 O(CO3 )2.H2 O:Yb/Er or Yb/Tm, to β-NaGdF4 :Yb/Er or Yb/Tm. The polyelectrolyte on the outer surface of nanophosphors also provided an amine tag for PEGylation. This method is also employed to fabricate PEGylated magnetic upconversion phosphors with Fe3 O4 as the core and β-NaGdF4 as a shell. These magnetic upconversion nanophosphors have relatively high saturation magnetization (7.0 emu g(-1) ) and magnetic susceptibility (1.7 × 10(-2) emu g(-1) Oe(-1) ), providing them with large magnetophoretic mobilities. The magnetic properties for separation and controlled release in flow, their optical properties for cell labeling, deep tissue imaging, and their T1 - and T2 -weighted magnetic resonance imaging (MRI) relaxivities are studied. The magnetic upconversion phosphors display both strong magnetophoresis, dual MRI imaging (r1 = 2.9 mM(-1) s(-1) , r2 = 204 mM(-1) s(-1) ), and bright luminescence under 1 cm chicken breast tissue.
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Affiliation(s)
- Hongyu Chen
- Department of Chemistry, Center for optical materials science and engineering (COMSET), and environmental toxicology program, Clemson University, Clemson SC, 29634, USA
| | - Bin Qi
- Department of Materials Science Engineering, Center for optical materials science and engineering (COMSET), Clemson University, Clemson, SC 29634, USA
| | - Thomas Moore
- Department of Bioengineering, 301 Rhodes Research Center, Clemson, SC 29634, USA
| | - Daniel C. Colvin
- Vanderbilt University Medical Center, AAA 3107 MCN, Nashville, TN 37232, USA
| | - Thomas Crawford
- Department of Physics and Astronomy and Smart State Center for Experimental Nanoscale Physics, University of South Carolina, Columbia, SC
| | - John C. Gore
- Vanderbilt University Medical Center, AAA 3107 MCN, Nashville, TN 37232, USA
| | - Frank Alexis
- Department of Bioengineering, 301 Rhodes Research Center, Clemson, SC 29634, USA
| | - O. Thompson Mefford
- Department of Materials Science Engineering, Center for optical materials science and engineering (COMSET), Clemson University, Clemson, SC 29634, USA
| | - Jeffrey N. Anker
- Department of Chemistry, Center for optical materials science and engineering (COMSET), and environmental toxicology program, Clemson University, Clemson SC, 29634, USA
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10
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Whisenant JG, Ayers GD, Loveless ME, Barnes SL, Colvin DC, Yankeelov TE. Assessing reproducibility of diffusion-weighted magnetic resonance imaging studies in a murine model of HER2+ breast cancer. Magn Reson Imaging 2013; 32:245-9. [PMID: 24433723 DOI: 10.1016/j.mri.2013.10.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/27/2013] [Accepted: 10/22/2013] [Indexed: 01/22/2023]
Abstract
BACKGROUND AND PURPOSE The use of diffusion-weighted magnetic resonance imaging (DW-MRI) as a surrogate biomarker of response in preclinical studies is increasing. However, before a biomarker can be reliably employed to assess treatment response, the reproducibility of the technique must be established. There is a paucity of literature that quantifies the reproducibility of DW-MRI in preclinical studies; thus, the purpose of this study was to investigate DW-MRI reproducibility in a murine model of HER2+ breast cancer. MATERIALS AND METHODS Test-Retest DW-MRI scans separated by approximately six hours were acquired from eleven athymic female mice with HER2+ xenografts using a pulsed gradient spin echo diffusion-weighted sequence with three b values [150, 500, and 800s/mm(2)]. Reproducibility was assessed for the mean apparent diffusion coefficient (ADC) from tumor and muscle tissue regions. RESULTS The threshold to reflect a change in tumor physiology in a cohort of mice is defined by the 95% confidence interval (CI), which was±0.0972×10(-3)mm(2)/s (±11.8%) for mean tumor ADC. The repeatability coefficient defines this threshold for an individual mouse, which was±0.273×10(-3)mm(2)/s. The 95% CI and repeatability coefficient for mean ADC of muscle tissue were±0.0949×10(-3)mm(2)/s (±8.30%) and±0.266×10(-3)mm(2)/s, respectively. CONCLUSIONS Mean ADC of tumors is reproducible and appropriate for detecting treatment-induced changes on both an individual and mouse cohort basis.
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Affiliation(s)
- Jennifer G Whisenant
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee 37232-2675
| | - Gregory D Ayers
- Department of Biostatistics, Vanderbilt University, Nashville, Tennessee 37232-2675
| | - Mary E Loveless
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232-2675
| | - Stephanie L Barnes
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee 37232-2675
| | - Daniel C Colvin
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee 37232-2675
| | - Thomas E Yankeelov
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee 37232-2675; Department of Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37232-2675.
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11
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Chen H, Moore T, Qi B, Colvin DC, Jelen EK, Hitchcock DA, He J, Mefford OT, Gore JC, Alexis F, Anker JN. Monitoring pH-triggered drug release from radioluminescent nanocapsules with X-ray excited optical luminescence. ACS Nano 2013; 7:1178-87. [PMID: 23281651 PMCID: PMC3612352 DOI: 10.1021/nn304369m] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
One of the greatest challenges in cancer therapy is to develop methods to deliver chemotherapy agents to tumor cells while reducing systemic toxicity to noncancerous cells. A promising approach to localizing drug release is to employ drug-loaded nanoparticles with coatings that release the drugs only in the presence of specific triggers found in the target cells such as pH, enzymes, or light. However, many parameters affect the nanoparticle distribution and drug release rate, and it is difficult to quantify drug release in situ. In this work, we show proof-of-principle for a "smart" radioluminescent nanocapsule with an X-ray excited optical luminescence (XEOL) spectrum that changes during release of the optically absorbing chemotherapy drug, doxorubicin. XEOL provides an almost background-free luminescent signal for measuring drug release from particles irradiated by a narrow X-ray beam. We study in vitro pH-triggered release rates of doxorubicin from nanocapsules coated with a pH-responsive polyelectrolyte multilayer using HPLC and XEOL spectroscopy. The doxorubicin was loaded to over 5% by weight and released from the capsule with a time constant in vitro of ∼36 days at pH 7.4 and 21 h at pH 5.0, respectively. The Gd₂O₂S:Eu nanocapsules are also paramagnetic at room temperature with similar magnetic susceptibility and similarly good MRI T₂ relaxivities to Gd₂O₃, but the sulfur increases the radioluminescence intensity and shifts the spectrum. Empty nanocapsules did not affect cell viability up to concentrations of at least 250 μg/mL. These empty nanocapsules accumulated in a mouse liver and spleen following tail vein injection and could be observed in vivo using XEOL. The particles are synthesized with a versatile template synthesis technique which allows for control of particle size and shape. The XEOL analysis technique opens the door to noninvasive quantification of drug release as a function of nanoparticle size, shape, surface chemistry, and tissue type.
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Affiliation(s)
- Hongyu Chen
- Department of Chemistry, Center for optical materials science and engineering technology (COMSET), and environmental toxicology program; Clemson University, Clemson, SC, 29634, USA
| | - Thomas Moore
- Department of Bioengineering, Clemson University, Clemson, SC, 29634, USA
| | - Bin Qi
- Department of Materials Science Engineering, Clemson University, Clemson, SC, 29634, USA
| | - Daniel C. Colvin
- Institute of Imaging Science (VUIIS), Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | - Erika K. Jelen
- Department of Bioengineering, Clemson University, Clemson, SC, 29634, USA
| | - Dale A. Hitchcock
- Department of Physics & Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Jian He
- Department of Physics & Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - O. Thompson Mefford
- Department of Materials Science Engineering, Clemson University, Clemson, SC, 29634, USA
| | - John C. Gore
- Institute of Imaging Science (VUIIS), Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | - Frank Alexis
- Department of Bioengineering, Clemson University, Clemson, SC, 29634, USA
| | - Jeffrey N. Anker
- Department of Chemistry, Center for optical materials science and engineering technology (COMSET), and environmental toxicology program; Clemson University, Clemson, SC, 29634, USA
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12
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Noto JM, Gaddy JA, Lee JY, Piazuelo MB, Friedman DB, Colvin DC, Romero-Gallo J, Suarez G, Loh J, Slaughter JC, Tan S, Morgan DR, Wilson KT, Bravo LE, Correa P, Cover TL, Amieva MR, Peek RM. Iron deficiency accelerates Helicobacter pylori-induced carcinogenesis in rodents and humans. J Clin Invest 2012; 123:479-92. [PMID: 23257361 DOI: 10.1172/jci64373] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 09/27/2012] [Indexed: 12/13/2022] Open
Abstract
Gastric adenocarcinoma is strongly associated with Helicobacter pylori infection; however, most infected persons never develop this malignancy. H. pylori strains harboring the cag pathogenicity island (cag+), which encodes CagA and a type IV secretion system (T4SS), induce more severe disease outcomes. H. pylori infection is also associated with iron deficiency, which similarly augments gastric cancer risk. To define the influence of iron deficiency on microbial virulence in gastric carcinogenesis, Mongolian gerbils were maintained on iron-depleted diets and infected with an oncogenic H. pylori cag+ strain. Iron depletion accelerated the development of H. pylori-induced premalignant and malignant lesions in a cagA-dependent manner. H. pylori strains harvested from iron-depleted gerbils or grown under iron-limiting conditions exhibited enhanced virulence and induction of inflammatory factors. Further, in a human population at high risk for gastric cancer, H. pylori strains isolated from patients with the lowest ferritin levels induced more robust proinflammatory responses compared with strains isolated from patients with the highest ferritin levels, irrespective of histologic status. These data demonstrate that iron deficiency enhances H. pylori virulence and represents a measurable biomarker to identify populations of infected persons at high risk for gastric cancer.
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Affiliation(s)
- Jennifer M Noto
- Division of Gastroenterology, Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
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13
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Noto JM, Gaddy JA, Lee JY, Piazuelo MB, Friedman DB, Colvin DC, Romero-Gallo J, Suarez G, Loh J, Slaughter JC, Tan S, Morgan DR, Wilson KT, Bravo LE, Correa P, Cover TL, Amieva MR, Peek RM. Iron deficiency accelerates Helicobacter pylori-induced carcinogenesis in rodents and humans. J Clin Invest 2012. [PMID: 23257361 DOI: 10.1172/jci6437364373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Gastric adenocarcinoma is strongly associated with Helicobacter pylori infection; however, most infected persons never develop this malignancy. H. pylori strains harboring the cag pathogenicity island (cag+), which encodes CagA and a type IV secretion system (T4SS), induce more severe disease outcomes. H. pylori infection is also associated with iron deficiency, which similarly augments gastric cancer risk. To define the influence of iron deficiency on microbial virulence in gastric carcinogenesis, Mongolian gerbils were maintained on iron-depleted diets and infected with an oncogenic H. pylori cag+ strain. Iron depletion accelerated the development of H. pylori-induced premalignant and malignant lesions in a cagA-dependent manner. H. pylori strains harvested from iron-depleted gerbils or grown under iron-limiting conditions exhibited enhanced virulence and induction of inflammatory factors. Further, in a human population at high risk for gastric cancer, H. pylori strains isolated from patients with the lowest ferritin levels induced more robust proinflammatory responses compared with strains isolated from patients with the highest ferritin levels, irrespective of histologic status. These data demonstrate that iron deficiency enhances H. pylori virulence and represents a measurable biomarker to identify populations of infected persons at high risk for gastric cancer.
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Affiliation(s)
- Jennifer M Noto
- Division of Gastroenterology, Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
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14
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Attia AS, Schroeder KA, Seeley EH, Wilson KJ, Hammer ND, Colvin DC, Manier ML, Nicklay JJ, Rose KL, Gore JC, Caprioli RM, Skaar EP. Monitoring the inflammatory response to infection through the integration of MALDI IMS and MRI. Cell Host Microbe 2012; 11:664-73. [PMID: 22704626 DOI: 10.1016/j.chom.2012.04.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 03/30/2012] [Accepted: 04/20/2012] [Indexed: 11/26/2022]
Abstract
Systemic bacterial infection is characterized by a robust whole-organism inflammatory response. Analysis of the immune response to infection involves technologies that typically focus on single organ systems and lack spatial information. Additionally, the analysis of individual inflammatory proteins requires antibodies specific to the protein of interest, limiting the panel of proteins that can be analyzed. Herein we describe the application of matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) to mice systemically infected with Staphylococcus aureus to identify inflammatory protein masses that respond to infection throughout an entire infected animal. Integrating the resolution afforded by magnetic resonance imaging (MRI) with the sensitivity of MALDI IMS provides three-dimensional spatially resolved information regarding the distribution of innate immune proteins during systemic infection, allowing comparisons to in vivo structural information and soft-tissue contrast via MRI. Thus, integrating MALDI IMS with MRI provides a systems-biology approach to study inflammation during infection.
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Affiliation(s)
- Ahmed S Attia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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15
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Hong T, Lazarenko RM, Colvin DC, Flores RL, Zhang Q, Xu YQ. Effect of Competitive Surface Functionalization on Dual-Modality Fluorescence and Magnetic Resonance Imaging of Single-Walled Carbon Nanotubes. J Phys Chem C Nanomater Interfaces 2012; 116:16319-16324. [PMID: 26644813 PMCID: PMC4670557 DOI: 10.1021/jp305372z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
It is well-known that ionic surfactant coated single-walled carbon nanotubes (SWNTs) possess higher near-infrared fluorescence (NIRF) quantum yield than nonionic polymer functionalized SWNTs. However, the influence of surface functionalization on the magnetic properties of SWNTs for T2-weighted magnetic resonance imaging (MRI) has not been reported. Here, we demonstrate that SWNTs functionalized by nonionic polymers display superior T2 relaxivity for MRI as compared to those coated by ionic surfactants. This difference may indicate that micelle structures formed by ionic surfactants are sufficiently tight to partially exclude water protons from the iron catalysts attached to the ends of SWNTs. On the basis of the different effects of the two types of suspension agents on NIRF and MRI of functionalized SWNTs, we further explore the competitive surface functionalization between ionic surfactants and nonionic polymers by stepwise replacing ionic surfactant molecules in a nanotube suspension with nonionic polymers. The superior NIRF of ionic surfactant coated SWNTs gradually quenches whereas no improvement on T2 relaxivity is observed during this replacement process. This result may indicate that nonionic polymers wrap around the outside of micelle structures to form small nanotube bundles rather than replacing ionic surfactants in the micelle structures to directly interact with the SWNT surface. Finally, we demonstrate the feasibility of dual-modality NIRF and MRI of nonionic polymer functionalized SWNTs in brain cells.
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Affiliation(s)
- Tu Hong
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Roman M. Lazarenko
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Daniel C. Colvin
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Roel L. Flores
- Interdisciplinary Program in Materials Science, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Qi Zhang
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Ya-Qiong Xu
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235, United States
- Interdisciplinary Program in Materials Science, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States
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16
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Chen H, Colvin DC, Qi B, Moore T, He J, Mefford OT, Alexis F, Gore JC, Anker JN. Magnetic and optical properties of multifunctional core-shell radioluminescence nanoparticles. J Mater Chem 2012; 22:12802-12809. [PMID: 24520183 PMCID: PMC3918467 DOI: 10.1039/c2jm15444g] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
When X-rays irradiate radioluminescence nanoparticles, they generate visible and near infrared light that can penetrate through centimeters of tissue. X-ray luminescence tomography (XLT) maps the location of these radioluminescent contrast agents at high resolution by scanning a narrow X-ray beam through the tissue sample and collecting the luminescence at every position. Adding magnetic functionality to these radioluminescent particles would enable them to be guided, oriented, and heated using external magnetic fields, while their location and spectrum could be imaged with XLT and complementary magnetic resonance imaging. In this work, multifunctional monodispersed magnetic radioluminescent nanoparticles were developed as potential drug delivery carriers and radioluminescence imaging agents. The particles consisted of a spindle-shaped magnetic γ-Fe2O3 core and a radioluminescent europium-doped gadolinium oxide shell. Particles with solid iron oxide cores displayed saturation magnetizations consistent with their ~13% core volume, however, the iron oxide quenched their luminescence. In order to increase the luminescence, we partially etched the iron oxide core in oxalic acid while preserving the radioluminescent shell. The core size was controlled by the etching time which in turn affected the particles' luminescence and magnetic properties. Particles with intermediate core sizes displayed both strong magnetophoresis and luminescence properties. They also served as MRI contrast agents with relaxivities of up to 58 mM-1s-1 (r2) and 120 mM-1s-1 (r2*). These particles offer promising multimodal MRI/fluorescence/X-ray luminescence contrast agents. Our core-shell synthesis technique offers a flexible method to control particle size, shape, and composition for a wide range of biological applications of magnetic/luminescent nanoparticles.
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Affiliation(s)
- Hongyu Chen
- Department of Chemistry, Center for optical materials science and engineering (COMSET), and environmental toxicology program; Clemson University, Clemson, SC, 29634, USA
| | - Daniel C. Colvin
- Vanderbilt University Institute of Imaging Science (VUIIS), Department of Radiology and Radiological Sciences Vanderbilt University, Nashville, TN, 37232, USA
| | - Bin Qi
- School of Materials Science and Engineering, Clemson University, Clemson, SC, 29634, USA
| | - Thomas Moore
- Department of Bioengineering, Clemson University, Clemson, SC, 29634, USA
| | - Jian He
- Department of Physics & Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - O. Thompson Mefford
- School of Materials Science and Engineering, Clemson University, Clemson, SC, 29634, USA
| | - Frank Alexis
- Department of Bioengineering, Clemson University, Clemson, SC, 29634, USA
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science (VUIIS), Department of Radiology and Radiological Sciences Vanderbilt University, Nashville, TN, 37232, USA
| | - Jeffrey N. Anker
- Department of Chemistry, Center for optical materials science and engineering (COMSET), and environmental toxicology program; Clemson University, Clemson, SC, 29634, USA
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17
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Choe AS, Stepniewska I, Colvin DC, Ding Z, Anderson AW. Validation of diffusion tensor MRI in the central nervous system using light microscopy: quantitative comparison of fiber properties. NMR Biomed 2012; 25:900-908. [PMID: 22246940 DOI: 10.1002/nbm.v25.7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 09/05/2011] [Accepted: 10/18/2011] [Indexed: 05/22/2023]
Abstract
Diffusion tensor imaging (DTI) provides an indirect measure of tissue structure on a microscopic scale. To date, DTI is the only imaging method that provides such information in vivo, and has proven to be a valuable tool in both research and clinical settings. In this study, we investigated the relationship between white matter structure and diffusion parameters measured by DTI. We used micrographs from light microscopy of fixed, myelin-stained brain sections as a gold standard for direct comparison with data from DTI. Relationships between microscopic tissue properties observed with light microscopy (fiber orientation, density and coherence) and fiber properties observed by DTI (tensor orientation, diffusivities and fractional anisotropy) were investigated. Agreement between the major eigenvector of the tensor and myelinated fibers was excellent in voxels with high fiber coherence. In addition, increased fiber spread was strongly associated with increased radial diffusivity (p = 6 × 10(-6)) and decreased fractional anisotropy (p = 5 × 10(-8)), and was weakly associated with decreased axial diffusivity (p = 0.07). Increased fiber density was associated with increased fractional anisotropy (p = 0.03), and weakly associated with decreased radial diffusivity (p < 0.06), but not with axial diffusivity (p = 0.97). The mean diffusivity was largely independent of fiber spread (p = 0.24) and fiber density (p = 0.34).
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Affiliation(s)
- A S Choe
- Vanderbilt University Institute of Imaging Science, Nashville, TN, USA.
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18
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Choe AS, Stepniewska I, Colvin DC, Ding Z, Anderson AW. Validation of diffusion tensor MRI in the central nervous system using light microscopy: quantitative comparison of fiber properties. NMR Biomed 2012; 25:900-8. [PMID: 22246940 PMCID: PMC4818098 DOI: 10.1002/nbm.1810] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 09/05/2011] [Accepted: 10/18/2011] [Indexed: 05/11/2023]
Abstract
Diffusion tensor imaging (DTI) provides an indirect measure of tissue structure on a microscopic scale. To date, DTI is the only imaging method that provides such information in vivo, and has proven to be a valuable tool in both research and clinical settings. In this study, we investigated the relationship between white matter structure and diffusion parameters measured by DTI. We used micrographs from light microscopy of fixed, myelin-stained brain sections as a gold standard for direct comparison with data from DTI. Relationships between microscopic tissue properties observed with light microscopy (fiber orientation, density and coherence) and fiber properties observed by DTI (tensor orientation, diffusivities and fractional anisotropy) were investigated. Agreement between the major eigenvector of the tensor and myelinated fibers was excellent in voxels with high fiber coherence. In addition, increased fiber spread was strongly associated with increased radial diffusivity (p = 6 × 10(-6)) and decreased fractional anisotropy (p = 5 × 10(-8)), and was weakly associated with decreased axial diffusivity (p = 0.07). Increased fiber density was associated with increased fractional anisotropy (p = 0.03), and weakly associated with decreased radial diffusivity (p < 0.06), but not with axial diffusivity (p = 0.97). The mean diffusivity was largely independent of fiber spread (p = 0.24) and fiber density (p = 0.34).
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Affiliation(s)
- A S Choe
- Vanderbilt University Institute of Imaging Science, Nashville, TN, USA.
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19
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Atuegwu NC, Colvin DC, Loveless ME, Xu L, Gore JC, Yankeelov TE. Incorporation of diffusion-weighted magnetic resonance imaging data into a simple mathematical model of tumor growth. Phys Med Biol 2012; 57:225-40. [PMID: 22156038 DOI: 10.1088/0031-9155/57/1/225] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We build on previous work to show how serial diffusion-weighted MRI (DW-MRI) data can be used to estimate proliferation rates in a rat model of brain cancer. Thirteen rats were inoculated intracranially with 9L tumor cells; eight rats were treated with the chemotherapeutic drug 1,3-bis(2-chloroethyl)-1-nitrosourea and five rats were untreated controls. All animals underwent DW-MRI immediately before, one day and three days after treatment. Values of the apparent diffusion coefficient (ADC) were calculated from the DW-MRI data and then used to estimate the number of cells in each voxel and also for whole tumor regions of interest. The data from the first two imaging time points were then used to estimate the proliferation rate of each tumor. The proliferation rates were used to predict the number of tumor cells at day three, and this was correlated with the corresponding experimental data. The voxel-by-voxel analysis yielded Pearson’s correlation coefficients ranging from −0.06 to 0.65, whereas the region of interest analysis provided Pearson’s and concordance correlation coefficients of 0.88 and 0.80, respectively. Additionally, the ratio of positive to negative proliferation values was used to separate the treated and control animals (p <0.05) at an earlier point than the mean ADC values. These results further illustrate how quantitative measurements of tumor state obtained non-invasively by imaging can be incorporated into mathematical models that predict tumor growth.
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Affiliation(s)
- N C Atuegwu
- Institute of Imaging Science, Vanderbilt University Nashville, TN, USA
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20
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Tucker – Schwartz JM, Hong T, Colvin DC, Xu Y, Skala MC. Dual-modality photothermal optical coherence tomography and magnetic-resonance imaging of carbon nanotubes. Opt Lett 2012; 37:872-4. [PMID: 22378422 PMCID: PMC3390748 DOI: 10.1364/ol.37.000872] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We demonstrate polyethylene-glycol-coated single-walled carbon nanotubes (CNTs) as contrast agents for both photothermal optical coherence tomography (OCT) and magnetic-resonance imaging (MRI). Photothermal OCT was accomplished with a spectral domain OCT system with an amplitude-modulated 750 nm pump beam using 10 mW of power, and T(2) MRI was achieved with a 4.7 T animal system. Photothermal OCT and T(2) MRI achieved sensitivities of nanomolar concentrations to CNTs dispersed in amine-terminated polyethylene glycol, thus establishing the potential for dual-modality molecular imaging with CNTs.
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Affiliation(s)
- Jason M. Tucker – Schwartz
- Department of Biomedical Engineering, Vanderbilt University, VU Station B Box 351631, Nashville TN, 37235
| | - Tu Hong
- Department of Electrical Engineering and Computer Science, Vanderbilt University, 2301 Vanderbilt Place, Nashville TN, 37235
| | - Daniel C. Colvin
- Department of Radiology and Radiological Sciences, Vanderbilt University, 1161 21st Ave South, Medical Center North, Nashville TN, 37232
| | - Yaqiong Xu
- Department of Electrical Engineering and Computer Science, Vanderbilt University, 2301 Vanderbilt Place, Nashville TN, 37235
| | - Melissa C. Skala
- Department of Biomedical Engineering, Vanderbilt University, VU Station B Box 351631, Nashville TN, 37235
- Corresponding author:
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21
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Tang D, Hight MR, McKinley ET, Fu A, Buck JR, Smith RA, Tantawy MN, Peterson TE, Colvin DC, Ansari MS, Nickels M, Manning HC. Quantitative preclinical imaging of TSPO expression in glioma using N,N-diethyl-2-(2-(4-(2-18F-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide. J Nucl Med 2012; 53:287-94. [PMID: 22251555 DOI: 10.2967/jnumed.111.095653] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
UNLABELLED There is a critical need to develop and rigorously validate molecular imaging biomarkers to aid diagnosis and characterization of primary brain tumors. Elevated expression of translocator protein (TSPO) has been shown to predict disease progression and aggressive, invasive behavior in a variety of solid tumors. Thus, noninvasive molecular imaging of TSPO expression could form the basis of a novel, predictive cancer imaging biomarker. In quantitative preclinical PET studies, we evaluated a high-affinity pyrazolopyrimidinyl-based TSPO imaging ligand, N,N-diethyl-2-(2-(4-(2-(18)F-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide ((18)F-DPA-714), as a translational probe for quantification of TSPO levels in glioma. METHODS Glioma-bearing rats were imaged with (18)F-DPA-714 in a small-animal PET system. Dynamic images were acquired simultaneously on injection of (18)F-DPA-714 (130-200 MBq/0.2 mL). Blood was collected to derive the arterial input function (AIF), with high-performance liquid chromatography radiometabolite analysis performed on selected samples for AIF correction. Compartmental modeling was performed using the corrected AIF. Specific tumor cell binding of DPA-714 was evaluated by radioligand displacement of (3)H-PK 11195 with DPA-714 in vitro and displacement of (18)F-DPA-714 with an excess of DPA-714 in vivo. Immediately after imaging, tumor and healthy brain tissues were harvested for validation by Western blotting and immunohistochemistry. RESULTS (18)F-DPA-714 was found to preferentially accumulate in tumors, with modest uptake in the contralateral brain. Infusion with DPA-714 (10 mg/kg) displaced (18)F-DPA-714 binding by greater than 60% on average. Tumor uptake of (18)F-DPA-714 was similar to another high-affinity TSPO imaging ligand, (18)F-N-fluoroacetyl-N-(2,5-dimethoxybenzyl)-2-phenoxyaniline, and agreed with ex vivo assay of TSPO levels in tumor and healthy brain. CONCLUSION These studies illustrate the feasibility of using (18)F-DPA-714 for visualization of TSPO-expressing brain tumors. Importantly, (18)F-DPA-714 appears suitable for quantitative assay of tumor TSPO levels in vivo. Given the relationship between elevated TSPO levels and poor outcome in oncology, these studies suggest the potential of (18)F-DPA-714 PET to serve as a novel predictive cancer imaging modality.
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Affiliation(s)
- Dewei Tang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
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Cole HA, Ichikawa J, Colvin DC, O'Rear L, Schoenecker JG. Quantifying intra-osseous growth of osteosarcoma in a murine model with radiographic analysis. J Orthop Res 2011; 29:1957-62. [PMID: 21656849 DOI: 10.1002/jor.21474] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 05/18/2011] [Indexed: 02/04/2023]
Abstract
The orthotopic murine osteosarcoma model is an excellent representation of the human condition as mice develop rapid growth of 'primary' tumor with subsequent lung metastasis. Currently, monitoring tumor growth relies on measuring pulmonary metastases occurring four weeks post injection. Studies show that amputation of the tumor-bearing limb is required before pulmonary metastases are detectable due to rapid growth causing morbidity. Thus, a method measuring 'primary' tumor growth independent of metastasis is required. We hypothesized that serial radiography would allow for longitudinal quantification of 'primary' osteosarcoma growth and explored this idea by utilizing the tibial orthotopic model. Tumor growth was monitored weekly by radiography and calipers, and results were compared with µCT and histology. We found that radiographs demonstrate extra and intra-osseous tumor growth by displaying lytic and blastic lesions and the surrounding radio-opaque area enlarged significantly (p < 0.0001) allowing for quantification. Additionally, radiographs proved more precise than indirect caliper measurements (intra-observer error ±6.64%: inter-observer error ±15.84%). Therefore, we determined that radiography provides accurate, longitudinal quantification of 'primary' osteosarcoma tumor that can be performed serially in the same mouse, does not require introduction of bioluminescence to the host or cell, and is more precise than the current caliper method.
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Affiliation(s)
- Heather A Cole
- Department of Orthopaedics and Rehabilitation, Vanderbilt University Medical Center, 1211 Medical Center Dr., Nashville, TN 37232, USA
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23
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Colvin DC, Loveless ME, Does MD, Yue Z, Yankeelov TE, Gore JC. Earlier detection of tumor treatment response using magnetic resonance diffusion imaging with oscillating gradients. Magn Reson Imaging 2010; 29:315-23. [PMID: 21190804 DOI: 10.1016/j.mri.2010.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 10/23/2010] [Indexed: 11/12/2022]
Abstract
An improved method for detecting early changes in tumors in response to treatment, based on a modification of diffusion-weighted magnetic resonance imaging, has been demonstrated in an animal model. Early detection of therapeutic response in tumors is important both clinically and in pre-clinical assessments of novel treatments. Noninvasive imaging methods that can detect and assess tumor response early in the course of treatment, and before frank changes in tumor morphology are evident, are of considerable interest as potential biomarkers of treatment efficacy. Diffusion-weighted magnetic resonance imaging is sensitive to changes in water diffusion rates in tissues that result from structural variations in the local cellular environment, but conventional methods mainly reflect changes in tissue cellularity and do not convey information specific to microstructural variations at sub-cellular scales. We implemented a modified imaging technique using oscillating gradients of the magnetic field for evaluating water diffusion rates over very short spatial scales that are more specific for detecting changes in intracellular structure that may precede changes in cellularity. Results from a study of orthotopic 9L gliomas in rat brains indicate that this method can detect changes as early as 24 h following treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea, when conventional approaches do not find significant effects. These studies suggest that diffusion imaging using oscillating gradients may be used to obtain an earlier indication of treatment efficacy than previous magnetic resonance imaging methods.
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Affiliation(s)
- Daniel C Colvin
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232-2310, USA
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Xu J, Xie J, Jourquin J, Colvin DC, Does MD, Quaranta V, Gore JC. Influence of cell cycle phase on apparent diffusion coefficient in synchronized cells detected using temporal diffusion spectroscopy. Magn Reson Med 2010; 65:920-6. [PMID: 21413058 DOI: 10.1002/mrm.22704] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 09/24/2010] [Accepted: 10/03/2010] [Indexed: 11/10/2022]
Abstract
The relationship between the apparent diffusion coefficient of tissue water measured by MR methods and the physiological status of cells is of particular relevance for better understanding and interpretation of diffusion-weighted MRI. In addition, there is considerable interest in developing diffusion-dependent imaging methods capable of providing novel information on tissue microstructure, including intracellular changes. To this end, both the conventional pulsed gradient spin-echo methods and the oscillating gradient spin-echo method, which probes diffusion over very short distance (<<cell size) and time scales, were used to measure apparent diffusion coefficient of synchronized packed HL-60 cells at 7 T. The results show that the pulsed gradient spin-echo method with relatively long diffusion times does not detect changes in apparent diffusion coefficient when structural variations arise during cell division. On the contrary, the oscillating gradient spin-echo method can detect and quantify major changes in intracellular organization that occur during mitosis by appropriate choice of gradient frequency. Cell structural parameters, including cell size, intracellular diffusion coefficient, and surface-to-volume ratio were also obtained by fitting the oscillating gradient spin-echo data to simple analytical models. These oscillating gradient spin-echo features may be used in diffusion-weighted MRI to create parametric maps that may be useful for detecting cancer or changes caused by treatment.
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Affiliation(s)
- Junzhong Xu
- Vanderbilt University Institute of Imaging Science, Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee 37232-2310, USA.
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Colvin DC, Jourquin J, Xu J, Does MD, Estrada L, Gore JC. Effects of intracellular organelles on the apparent diffusion coefficient of water molecules in cultured human embryonic kidney cells. Magn Reson Med 2010; 65:796-801. [PMID: 21337411 DOI: 10.1002/mrm.22666] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 08/20/2010] [Accepted: 09/09/2010] [Indexed: 11/06/2022]
Abstract
The apparent diffusion coefficient (ADC) of water in tissues is dependent on the size and spacing of structures in the cellular environment and has been used to characterize pathological changes in stroke and cancer. However, the factors that affect ADC values remain incompletely understood. Measurements of ADC are usually made using relatively long diffusion times; so they reflect the integrated effects of cellular structures over a broad range of spatial scales. We used temporal diffusion spectroscopy to study diffusion in packed cultured human embryonic kidney cells over a range of effective diffusion times following microtubule and actin/cytoskeleton depolymerization and disassembly of the Golgi complex. While Golgi disruption did not change ADC, depolymerization of the microtubule and the actin filament networks caused small decreases in ADC at short diffusion times only. Temporal diffusion spectroscopy provided a novel way to assess intracellular influences on the diffusion properties of tissue water.
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Affiliation(s)
- Daniel C Colvin
- Institute of Imaging Science, Department of Physics and Astronomy, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37232-2310, USA
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Gore JC, Xu J, Colvin DC, Yankeelov TE, Parsons EC, Does MD. Characterization of tissue structure at varying length scales using temporal diffusion spectroscopy. NMR Biomed 2010; 23:745-56. [PMID: 20677208 PMCID: PMC3285511 DOI: 10.1002/nbm.1531] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The concepts, theoretical behavior and experimental applications of temporal diffusion spectroscopy are reviewed and illustrated. Temporal diffusion spectra are obtained using oscillating-gradient waveforms in diffusion-weighted measurements, and represent the manner in which various spectral components of molecular velocity correlations vary in different geometrical structures that restrict or hinder free movements. Measurements made at different gradient frequencies reveal information on the scale of restrictions or hindrances to free diffusion, and the shape of a spectrum reveals the relative contributions of spatial restrictions at different distance scales. Such spectra differ from other so-called diffusion spectra which depict spatial frequencies and are defined at a fixed diffusion time. Experimentally, oscillating gradients at moderate frequency are more feasible for exploring restrictions at very short distances which, in tissues, correspond to structures smaller than cells. We describe the underlying concepts of temporal diffusion spectra and provide analytical expressions for the behavior of the diffusion coefficient as a function of gradient frequency in simple geometries with different dimensions. Diffusion in more complex model media that mimic tissues has been simulated using numerical methods. Experimental measurements of diffusion spectra have been obtained in suspensions of particles and cells, as well as in vivo in intact animals. An observation of particular interest is the increased contrast and heterogeneity observed in tumors using oscillating gradients at moderate frequency compared with conventional pulse gradient methods, and the potential for detecting changes in tumors early in their response to treatment. Computer simulations suggest that diffusion spectral measurements may be sensitive to intracellular structures, such as nuclear size, and that changes in tissue diffusion properties may be measured before there are changes in cell density.
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Affiliation(s)
- John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232, USA.
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27
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Abstract
Magnetic resonance images (MRI) that depict rates of water diffusion in tissues can be used to characterize the cellularity of tumors and are valuable in assessing their early response to treatment. Water diffusion rates are sensitive to the cellular and molecular content of tissues and are affected by local microstructural changes associated with tumor development. However, conventional maps of water diffusion reflect the integrated effects of restrictions to free diffusion at multiple scales up to a specific limiting spatial dimension, typically several micrometers. Such measurements cannot distinguish effects caused by structural variations at a smaller scale. Variations in diffusion rates then largely reflect variations in the density of cells, and no information is available about changes on a subcellular scale. We report here our experiences using a new approach based on Oscillating Gradient Spin-Echo (OGSE) MRI methods that can differentiate the influence on water diffusion of structural changes on scales much smaller than the diameter of a single cell. MRIs of glioblastomas in rat brain in vivo show an increased contrast and spatial heterogeneity when diffusion measurements are selectively sensitized to shorter distance scales. These results show the benefit of OGSE methods for revealing microscopic variations in tumors in vivo and confirm that diffusion measurements depend on factors other than cellularity.
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Affiliation(s)
- Daniel C Colvin
- Institute of Imaging Science, Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
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Anderson AW, Choe AS, Stepniewska I, Colvin DC. Comparison of brain white matter fiber orientation measurements based on diffusion tensor imaging and light microscopy. Conf Proc IEEE Eng Med Biol Soc 2008; 2006:2249-51. [PMID: 17946945 DOI: 10.1109/iembs.2006.259554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Diffusion tensor magnetic resonance imaging (MRI) was used to estimate white matter fiber orientations in fixed brain specimens. The specimens were subsequently sectioned, stained for myelinated fibers, and imaged with light microscopy. The MRI data were registered with the micrographs, allowing direct comparison of fiber orientation estimates between the two methods. Fiber orientation was measured in regions of interest in the frontal lateral corpus callosum. The results of diffusion MRI and light microscopy agreed within 2 degrees-the difference was not statistically significant.
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Affiliation(s)
- Adam W Anderson
- Biomedical Engineering Department and Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232, USA.
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29
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Berens SA, Colvin DC, Yu CG, Yezierski RP, Mareci TH. Evaluation of the pathologic characteristics of excitotoxic spinal cord injury with MR imaging. AJNR Am J Neuroradiol 2005; 26:1612-22. [PMID: 16091503 PMCID: PMC7975169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
BACKGROUND AND PURPOSE Although high-resolution MR imaging is a valuable diagnostic tool, in vivo MR imaging has not yet been compared with in vitro MR imaging and histologic techniques following experimental spinal cord injury (SCI). The goal of the present study was to evaluate the feasibility of using in vivo MR imaging, in vitro MR imaging, and histologic techniques to study pathologic changes associated with excitotoxic SCI at a single time point. These results are important for future research using in vivo MR imaging to study the temporal profile of pathologic changes following SCI. METHODS Rats received intraspinal injections of quisqualic acid at the T12-L2 spinal level. In vivo T1- and T2-weighted and dynamic contrast-enhanced MR images were collected 17-24 days postinjury. Once completed, spinal cords were removed and in vitro MR microscopy and histologic assessment were performed. MR images were collected using 4.7-T (in vivo) and 14.1-T magnets (in vitro). RESULTS Pathologic changes--including hemorrhage, neuronal loss, cavities, and central canal expansion--were visible in T2-weighted in vivo MR images. Evaluation of the blood-spinal cord barrier after injury with contrast agent enhancement showed no disruption at the time points evaluated. In vitro MR images and histologic evaluation confirmed pathologic details observed in vivo. CONCLUSION Results show that high-resolution in vivo MR imaging has the potential to be used in studying the progression of pathologic changes at multiple time points following SCI. This strategy may provide a way of studying structure-function relationships between therapeutic interventions and different pathologic characteristics of the injured spinal cord.
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Affiliation(s)
- Sara A Berens
- Comprehensive Center for Pain Research, University of Florida, Gainesville, FL, USA
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