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Cheng HLM. A primer on in vivo cell tracking using MRI. Front Med (Lausanne) 2023; 10:1193459. [PMID: 37324153 PMCID: PMC10264782 DOI: 10.3389/fmed.2023.1193459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/12/2023] [Indexed: 06/17/2023] Open
Abstract
Cell tracking by in vivo magnetic resonance imaging (MRI) offers a collection of multiple advantages over other imaging modalities, including high spatial resolution, unlimited depth penetration, 3D visualization, lack of ionizing radiation, and the potential for long-term cell monitoring. Three decades of innovation in both contrast agent chemistry and imaging physics have built an expansive array of probes and methods to track cells non-invasively across a diverse range of applications. In this review, we describe both established and emerging MRI cell tracking approaches and the variety of mechanisms available for contrast generation. Emphasis is given to the advantages, practical limitations, and persistent challenges of each approach, incorporating quantitative comparisons where possible. Toward the end of this review, we take a deeper dive into three key application areas - tracking cancer metastasis, immunotherapy for cancer, and stem cell regeneration - and discuss the cell tracking techniques most suitable to each.
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Affiliation(s)
- Hai-Ling Margaret Cheng
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
- Ted Rogers Centre for Heart Research, Translational Biology & Engineering Program, Toronto, ON, Canada
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2
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Liu T, Li Z, Li X, Zhao R, Wei X, Wang Z, Xin SX. In vivo visualization of murine melanoma cells B16-derived exosomes through magnetic resonance imaging. Biochim Biophys Acta Gen Subj 2022; 1866:130062. [PMID: 34822924 DOI: 10.1016/j.bbagen.2021.130062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/22/2021] [Accepted: 11/17/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Numerous studies demonstrated that exosomes play a powerful role in mediating intercellular communication to induce a pro-tumoral environment to promote tumor progression, including pre-metastatic niche formation and metastasis. Noninvasive imaging could determine the in vivo kinetics of exosomes in real time to provide better understanding of the mechanisms of the tumor formation, progression and metastasis. Magnetic resonance imaging (MRI) is an ideal technique which provides excellent anatomical resolution, intrinsic soft tissue contrast, unlimited penetration depth and no radiation exposure. METHODS A fusion protein composed of ferritin heavy chain (FTH1) and lactadherin was designed for visualizing exosomes through MRI. FTH1 was served as MRI reporter protein and lactadherin is a membrane-associated protein that is distributed on exosome surface. The characterizations of labeled exosomes were validated through transmission electron microscopy, western blot, nanoparticle tracking analysis and finally visualized in vitro and in vivo through MRI. RESULTS MR imaging showed that the labeled exosomes are able to be visualized in vitro and in vivo. Verification of the characterizations of exosomes observed no significant difference between labeled and unlabeled exosomes. CONCLUSION The proposed FTH1 labeling method was useful for visualizing exosomes through MRI. GENERAL SIGNIFICANCE The present study first reported a novel self-label method for imaging labeled exosomes of tumor cells in vivo through MR with cell endogenous MRI reporter protein. It may be further used as a tool to enhance understanding the role of exosomes in various pathophysiological conditions.
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Affiliation(s)
- Tianqi Liu
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Zhenlin Li
- Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Xiaodong Li
- School of Medicine, South China University of Technology, Guangzhou 510006, Guangdong, China
| | - Ruiting Zhao
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Xinhua Wei
- Department of Radiology, Guangzhou First People's Hospital, South China University of Technology, Guangzhou 510180, Guangdong, China
| | - Zixin Wang
- School of Electronics and Information Technology, Sun Yat-Sen University, Xingang Xi Road 135, Guangzhou 510275, Guangdong, China
| | - Sherman Xuegang Xin
- School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, Guangdong, China; School of Medicine, South China University of Technology, Guangzhou 510006, Guangdong, China.
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3
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Goel D, Sinha S. Naturally occurring protein nano compartments: basic structure, function, and genetic engineering. NANO EXPRESS 2021. [DOI: 10.1088/2632-959x/ac2c93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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4
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Ghaffari H, Atashzar MR, Abdollahi H. Molecular imaging in tracking cancer stem cells: A review. Med J Islam Repub Iran 2020; 34:90. [PMID: 33306061 PMCID: PMC7711048 DOI: 10.34171/mjiri.34.90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Indexed: 11/05/2022] Open
Abstract
Cancer stem cells (CSCs) have critical roles in tumor development, progression, and recurrence. They are responsible for current cancer treatment failure and remain questionable for the design and development of new therapeutic strategies. With this issue, medical imaging provides several clues for finding biological mechanisms and strategies to treat CSCs. This review aims to summarize current molecular imaging approaches for detecting CSCs. In addition, some promising issues for CSCs finding and explaining biological mechanisms have been addressed. Among the molecular imaging approaches, modalities including Magnetic resonance imaging (MRI) and positron emission tomography (PET) have the greatest roles and several new approaches such as optical imaging are in progress.
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Affiliation(s)
- Hamed Ghaffari
- Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Atashzar
- Department of Immunology, School of Medicine, Fasa University of Medical Sciences, Fasa, Iran
| | - Hamid Abdollahi
- Department of Radiologic Sciences and Medical Physics, School of Allied Medicine, Kerman University of Medical Sciences, Kerman, Iran
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5
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The Continuing Evolution of Molecular Functional Imaging in Clinical Oncology: The Road to Precision Medicine and Radiogenomics (Part II). Mol Diagn Ther 2019; 23:27-51. [PMID: 30387041 DOI: 10.1007/s40291-018-0367-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The present era of precision medicine sees "cancer" as a consequence of molecular derangements occurring at the commencement of the disease process, with morphological changes happening much later in the process of tumourigenesis. Conventional imaging techniques, such as computed tomography (CT), ultrasound (US) and magnetic resonance imaging (MRI) play an integral role in the detection of disease at the macroscopic level. However, molecular functional imaging (MFI) techniques entail the visualisation and quantification of biochemical and physiological processes occurring during tumourigenesis. MFI has the potential to play a key role in heralding the transition from the concept of "one-size-fits-all" treatment to "precision medicine". Integration of MFI with other fields of tumour biology such as genomics has spawned a novel concept called "radiogenomics", which could serve as an indispensable tool in translational cancer research. With recent advances in medical image processing, such as texture analysis, deep learning and artificial intelligence, the future seems promising; however, their clinical utility remains unproven at present. Despite the emergence of novel imaging biomarkers, the majority of these require validation before clinical translation is possible. In this two part review, we discuss the systematic collaboration across structural, anatomical and molecular imaging techniques that constitute MFI. Part I reviews positron emission tomography, radiogenomics, AI, and optical imaging, while part II reviews MRI, CT and ultrasound, their current status, and recent advances in the field of precision oncology.
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6
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He X, Cai J, Li H, Liu B, Qin Y, Zhong Y, Wang L, Liao Y. In Vivo magnetic resonance imaging of xenografted tumors using FTH1 reporter gene expression controlled by a tet-on switch. Oncotarget 2018; 7:78591-78604. [PMID: 27732930 PMCID: PMC5346662 DOI: 10.18632/oncotarget.12519] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 10/03/2016] [Indexed: 12/28/2022] Open
Abstract
As a promising magnetic resonance imaging (MRI) reporter, ferritin has been used to track cells in vivo; however, its continuous overexpression can be cytotoxic, which restricts its application. In this study, we aimed to develop a switch to turn this genetic reporter “on” or “off” while monitoring cell grafts via MRI. To accomplish this, we genetically modified the ferritin heavy chain (FTH1) with a Tet-On switch and assessed the expression of FTH1 in transduced neuroblastoma cells (SK-N-SH) in vitro and in xenografted tumors in vivo. We found that FTH1 expression induced by doxycycline (Dox) in SK-N-SH-FTH1 cells depended on treatment dose and duration. We successfully detected T2-weighted MRI contrast in cell grafts after switching “on” the reporter gene using Dox, and this contrast disappeared when we switched it “off”. The genetic reporter FTH1 can thus be switched “on” or “off” throughout longitudinal monitoring of cell grafts, limiting expression to when MRI contrast is needed. The controllable imaging system we have developed minimizes risks from constitutive reporter gene overexpression and facilitates tumor cell monitoring in vitro and in vivo.
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Affiliation(s)
- Xiaoya He
- Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Jinhua Cai
- Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Hao Li
- Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Bo Liu
- Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Yong Qin
- Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Yi Zhong
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Longlun Wang
- Department of Radiology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Yifan Liao
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
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Wang Z, Gao H, Zhang Y, Liu G, Niu G, Chen X. Functional ferritin nanoparticles for biomedical applications. Front Chem Sci Eng 2017; 11:633-646. [PMID: 29503759 DOI: 10.1007/s11705-017-1620-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ferritin, a major iron storage protein with a hollow interior cavity, has been reported recently to play many important roles in biomedical and bioengineering applications. Owing to the unique architecture and surface properties, ferritin nanoparticles offer favorable characteristics and can be either genetically or chemically modified to impart functionalities to their surfaces, and therapeutics or probes can be encapsulated in their interiors by controlled and reversible assembly/disassembly. There has been an outburst of interest regarding the employment of functional ferritin nanoparticles in nanomedicine. This review will highlight the recent advances in ferritin nanoparticles for drug delivery, bioassay, and molecular imaging with a particular focus on their biomedical applications.
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Affiliation(s)
- Zhantong Wang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China.,Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health, Bethesda, MD 20892, USA
| | - Haiyan Gao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Yang Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Gang Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Gang Niu
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health, Bethesda, MD 20892, USA
| | - Xiaoyuan Chen
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health, Bethesda, MD 20892, USA
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8
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Dai HY, He R, Zhang Y, Wu RH, Xiao YY. Adenoviral vector mediated ferritin over-expression in mesenchymal stem cells detected by 7T MRI in vitro. PLoS One 2017; 12:e0185260. [PMID: 28945778 PMCID: PMC5612726 DOI: 10.1371/journal.pone.0185260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 09/08/2017] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE The aim of the present work was to verify whether adenoviral vector mediated ferritin over-expression in mesenchymal stem cells could be detected by 7T MRI device, and to explore the relationship between ferritin content and MRI signal intensities. METHODS A recombined adenoviral vector (rAdV) encoding ferritin heavy chain (FTH1) subunit was specially designed for the aim of infecting bone marrow mesenchymal stem cells (BMSCs). Ferritin over-expression in BMSCs was determined by cell immunocytochemistry and the ferritin content in cells was determined by ELISA assay. BMSCs were subjected to cell viability, proliferation and multi-differentiation analyses as well as 7T MRI test using fast spin-echo pulse sequence. The R2 value andδR2 were calculated according to T2 mapping images. RESULTS As was confirmed by cell immunocytochemistry and ELISA assay, rAdV mediated ferritin was over-expressed in BMSCs. Ferritin over-expression did not interfere with stem cell viability or pluripotent differentiation but slowed cell proliferation. The R2 value of BMSCs-FTH1 vs control BMSCs from 1-4 weeks was16.65±1.28 s-1 vs 13.99±0.80 s-1, (t = 3.94, p = 0.004), 15.63±1.37 s-1 vs 13.87±0.83 s-1 (t = 2.47, p = 0.039), 15.53±0.88 s-1 vs 14.25±0.53 s-1 (t = 2.80, p = 0.023) and 14.61±1.28 s-1 vs 13.69±1.03 s-1 (t = 1.25, p = 0.24), respectively. δR2 gradually decreased from 1-4 weeks and the difference between the groups had statistical significance (F = 12.45, p<0.01).δR2 was positively correlated with OD value (r = 0.876, p<0.01) and ferritin concentration (r = 0.899, p<0.01) as determined by Pearson correlation. CONCLUSIONS Our study confirms that ferritin could be over-expressed in BMSCs as a result of rAdV mediated infection and could be quantitatively detected by 7T MRI device. The differences in T2 signal intensities and R2 values stem from internal contrast generated by endogenous ferritin over-expression. The correlation between δR2, OD and ferritin concentration suggests that MRI can detect ferritin signal change accurately.
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Affiliation(s)
- Hai-yang Dai
- Department of Medical Imaging, Huizhou Municipal Central Hospital, Huizhou, China
| | - Rong He
- Department of Medical Imaging, the 2 Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Ying Zhang
- Department of Medical Imaging, the 2 Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Ren-hua Wu
- Department of Medical Imaging, the 2 Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Ye-yu Xiao
- Department of Medical Imaging, the 2 Affiliated Hospital of Shantou University Medical College, Shantou, China
- * E-mail:
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9
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Qin X, Hu X, Wu C, Cai M, Li Z, Zhang L, Lin L, Huang W, Zhu K. Hepatocellular Carcinoma Cells Carrying a Multimodality Reporter Gene for Fluorescence, Bioluminescence, and Magnetic Resonance Imaging In Vitro and In Vivo. Acad Radiol 2016; 23:1422-1430. [PMID: 27641103 DOI: 10.1016/j.acra.2016.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 06/27/2016] [Accepted: 07/01/2016] [Indexed: 12/22/2022]
Abstract
RATIONALE AND OBJECTIVES The study aimed to evaluate the feasibility of imaging or tracking hepatocellular carcinoma cells by modifying these cells to carry a multimodality reporter gene, enabling fluorescence, bioluminescence, and magnetic resonance imaging (MRI) in vitro and in vivo. MATERIALS AND METHODS HepG2 cells were labeled with the enhanced green fluorescent protein (EGFP)/luciferase2/ferritin-the multimodality reporter gene (labeled HepG2 cells). The labeled and unlabeled HepG2 cells were cultured in vitro and then injected subcutaneously into mice as a hepatoma model in vivo. The expressions of EGFP, luciferase2, and ferritin in HepG2 cell suspensions and hepatoma model were investigated using fluorescence, bioluminescence, and MRI. RESULTS Individual HepG2 cells expressing EGFP were identified under blue laser excitation. The linear coefficient between the optical signal intensity of luciferase2 and the number of labeled cells was 0.993. MRI was used to distinguish the T2* signal of 2 × 107 cells/mL between the labeled (6.67 ± 1.88 ms) and unlabeled cells (10.66 ± 2.22 ms) (P = 0.034). In vivo, individual HepG2 cells expressing EGFP in frozen sections were observed. Labeled cells expressing luciferase2 have been detected since the second day after injection, and the bioluminescence increased with the tumor size. The T2* signal was significantly different between the labeled (6.04 ± 1.60 ms) and unlabeled cells (17.06 ± 2.17 ms) (P <0.001). CONCLUSIONS A multimodality reporter gene consisting of EGFP, luciferase2, and ferritin was successfully integrated into the HepG2 cell genome via a lentiviral vector and was highly expressed in the daughter cells. These cells could be detected by fluorescence, bioluminescence, and MRI in vitro and in vivo.
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Affiliation(s)
- Xiaoxiao Qin
- Department of Minimally Invasive Interventional Radiology, The Second Affiliated Hospital of Guangzhou Medical University, 250 East Changgang Road, Guangzhou 510260, Guangdong Province, China; Department of Radiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Xiaojun Hu
- Department of Radiology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Chun Wu
- Department of Radiology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China; Interventional Radiology Institute, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Mingyue Cai
- Department of Radiology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China; Interventional Radiology Institute, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Zhengran Li
- Department of Radiology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China; Interventional Radiology Institute, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Lina Zhang
- Department of Radiology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Liteng Lin
- Department of Radiology, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China; Interventional Radiology Institute, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Wensou Huang
- Department of Minimally Invasive Interventional Radiology, The Second Affiliated Hospital of Guangzhou Medical University, 250 East Changgang Road, Guangzhou 510260, Guangdong Province, China
| | - Kangshun Zhu
- Department of Minimally Invasive Interventional Radiology, The Second Affiliated Hospital of Guangzhou Medical University, 250 East Changgang Road, Guangzhou 510260, Guangdong Province, China.
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10
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MRI Reporter Genes for Noninvasive Molecular Imaging. Molecules 2016; 21:molecules21050580. [PMID: 27213309 PMCID: PMC6273230 DOI: 10.3390/molecules21050580] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 04/21/2016] [Accepted: 04/25/2016] [Indexed: 01/17/2023] Open
Abstract
Magnetic resonance imaging (MRI) is one of the most important imaging technologies used in clinical diagnosis. Reporter genes for MRI can be applied to accurately track the delivery of cell in cell therapy, evaluate the therapy effect of gene delivery, and monitor tissue/cell-specific microenvironments. Commonly used reporter genes for MRI usually include genes encoding the enzyme (e.g., tyrosinase and β-galactosidase), the receptor on the cells (e.g., transferrin receptor), and endogenous reporter genes (e.g., ferritin reporter gene). However, low sensitivity limits the application of MRI and reporter gene-based multimodal imaging strategies are common including optical imaging and radionuclide imaging. These can significantly improve diagnostic efficiency and accelerate the development of new therapies.
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11
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Pereira SM, Herrmann A, Moss D, Poptani H, Williams SR, Murray P, Taylor A. Evaluating the effectiveness of transferrin receptor-1 (TfR1) as a magnetic resonance reporter gene. CONTRAST MEDIA & MOLECULAR IMAGING 2016; 11:236-44. [PMID: 26929139 PMCID: PMC4981909 DOI: 10.1002/cmmi.1686] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 01/06/2016] [Accepted: 01/08/2016] [Indexed: 12/13/2022]
Abstract
Magnetic resonance (MR) reporter genes have the potential for tracking the biodistribution and fate of cells in vivo, thus allowing the safety, efficacy and mechanisms of action of cell-based therapies to be comprehensively assessed. In this study, we evaluate the effectiveness of the iron importer transferrin receptor-1 (TfR1) as an MR reporter gene in the model cell line CHO-K1. Overexpression of the TfR1 transgene led to a reduction in the levels of endogenous TfR1 mRNA, but to a 60-fold increase in total TfR1 protein levels. Although the mRNA levels of ferritin heavy chain-1 (Fth1) did not change, Fth1 protein levels increased 13-fold. The concentration of intracellular iron increased significantly, even when cells were cultured in medium that was not supplemented with iron and the amount of iron in the extracellular environment was thus at physiological levels. However, we found that, by supplementing the cell culture medium with ferric citrate, a comparable degree of iron uptake and MR contrast could be achieved in control cells that did not express the TfR1 transgene. Sufficient MR contrast to enable the cells to be detected in vivo following their administration into the midbrain of chick embryos was obtained irrespective of the reporter gene. We conclude that TfR1 is not an effective reporter and that, to track the biodistribution of cells with MR imaging in the short term, it is sufficient to simply culture cells in the presence of ferric citrate. Copyright © 2016 The Authors Contrast Media & Molecular Imaging Published by John Wiley & Sons Ltd.
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Affiliation(s)
- Sofia M Pereira
- Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Anne Herrmann
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Diana Moss
- Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Harish Poptani
- Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Steve R Williams
- Centre for Imaging Sciences, Oxford Road, University of Manchester, Manchester, UK
| | - Patricia Murray
- Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Arthur Taylor
- Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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12
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De Souza R, Spence T, Huang H, Allen C. Preclinical imaging and translational animal models of cancer for accelerated clinical implementation of nanotechnologies and macromolecular agents. J Control Release 2015; 219:313-330. [PMID: 26409122 DOI: 10.1016/j.jconrel.2015.09.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/22/2015] [Accepted: 09/22/2015] [Indexed: 01/08/2023]
Abstract
The majority of animal models of cancer have performed poorly in terms of predicting clinical performance of new therapeutics, which are most often first evaluated in patients with advanced, metastatic disease. The development and use of metastatic models of cancer may enhance clinical translatability of preclinical studies focused on the development of nanotechnology-based drug delivery systems and macromolecular therapeutics, potentially accelerating their clinical implementation. It is recognized that the development and use of such models are not without challenge. Preclinical imaging tools offer a solution by allowing temporal and spatial characterization of metastatic lesions. This paper provides a review of imaging methods applicable for evaluation of novel therapeutics in clinically relevant models of advanced cancer. An overview of currently utilized models of oncology in small animals is followed by image-based development and characterization of visceral metastatic cancer models. Examples of imaging tools employed for metastatic lesion detection, evaluation of anti-tumor and anti-metastatic potential and biodistribution of novel therapies, as well as the co-development and/or use of imageable surrogates of response, are also discussed. While the focus is on development of macromolecular and nanotechnology-based therapeutics, examples with small molecules are included in some cases to illustrate concepts and approaches that can be applied in the assessment of nanotechnologies or macromolecules.
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Affiliation(s)
- Raquel De Souza
- Leslie Dan Faculty of Pharmacy, 144 College Street, Toronto, Ontario M5S 3M2, Canada.
| | - Tara Spence
- Leslie Dan Faculty of Pharmacy, 144 College Street, Toronto, Ontario M5S 3M2, Canada
| | - Huang Huang
- DLVR Therapeutics, 661 University Avenue, Toronto, Ontario M5G 0A3, Canada
| | - Christine Allen
- Leslie Dan Faculty of Pharmacy, 144 College Street, Toronto, Ontario M5S 3M2, Canada.
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Abstract
The ability to identify key biomolecules and molecular changes associated with cancer malignancy and the capacity to monitor the therapeutic outcome against these targets is critically important for cancer treatment. Recent developments in molecular imaging based on magnetic resonance (MR) techniques have provided researchers and clinicians with new tools to improve most facets of cancer care. Molecular imaging is broadly described as imaging techniques used to detect molecular signature at the cellular and gene expression levels. This article reviews both established and emerging molecular MR techniques in oncology and discusses the potential of these techniques in improving the clinical cancer care. It also discusses how molecular MR, in conjunction with other structural and functional MR imaging techniques, paves the way for developing tailored treatment strategies to enhance cancer care.
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14
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Overexpression of the MRI Reporter Genes Ferritin and Transferrin Receptor Affect Iron Homeostasis and Produce Limited Contrast in Mesenchymal Stem Cells. Int J Mol Sci 2015; 16:15481-96. [PMID: 26184159 PMCID: PMC4519909 DOI: 10.3390/ijms160715481] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 06/24/2015] [Accepted: 07/02/2015] [Indexed: 11/17/2022] Open
Abstract
Imaging technologies that allow the non-invasive monitoring of stem cells in vivo play a vital role in cell-based regenerative therapies. Recently, much interest has been generated in reporter genes that enable simultaneous monitoring of the anatomical location and viability of cells using magnetic resonance imaging (MRI). Here, we investigate the efficacy of ferritin heavy chain-1 (Fth1) and transferrin receptor-1 (TfR1) as reporters for tracking mesenchymal stem cells. The overexpression of TfR1 was well tolerated by the cells but Fth1 was found to affect the cell’s iron homeostasis, leading to phenotypic changes in the absence of iron supplementation and an upregulation in transcript and protein levels of the cell’s endogenous transferrin receptor. Neither the sole overexpression of Fth1 nor TfR1 resulted in significant increases in intracellular iron content, although significant differences were seen when the two reporter genes were used in combination, in the presence of high concentrations of iron. The supplementation of the culture medium with iron sources was a more efficient means to obtain contrast than the use of reporter genes, where high levels of intracellular iron were reflected in transverse (T2) relaxation. The feasibility of imaging iron-supplemented cells by MRI is shown using a 3R-compliant chick embryo model.
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Kim HS, Woo J, Lee JH, Joo HJ, Choi Y, Kim H, Moon WK, Kim SJ. In vivo Tracking of Dendritic Cell using MRI Reporter Gene, Ferritin. PLoS One 2015; 10:e0125291. [PMID: 25993535 PMCID: PMC4439152 DOI: 10.1371/journal.pone.0125291] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 03/14/2015] [Indexed: 01/05/2023] Open
Abstract
The noninvasive imaging of dendritic cells (DCs) migrated into lymph nodes (LNs) can provide helpful information on designing DCs-based immunotherapeutic strategies. This study is to investigate the influence of transduction of human ferritin heavy chain (FTH) and green fluorescence protein (GFP) genes on inherent properties of DCs, and the feasibility of FTH as a magnetic resonance imaging (MRI) reporter gene to track DCs migration into LNs. FTH-DCs were established by the introduction of FTH and GFP genes into the DC cell line (DC2.4) using lentivirus. The changes in the rate of MRI signal decay (R2*) resulting from FTH transduction were analyzed in cell phantoms as well as popliteal LN of mice after subcutaneous injection of those cells into hind limb foot pad by using a multiple gradient echo sequence on a 9.4 T MR scanner. The transduction of FTH and GFP did not influence the proliferation and migration abilities of DCs. The expression of co-stimulatory molecules (CD40, CD80 and CD86) in FTH-DCs was similar to that of DCs. FTH-DCs exhibited increased iron storage capacity, and displayed a significantly higher transverse relaxation rate (R2*) as compared to DCs in phantom. LNs with FTH-DCs exhibited negative contrast, leading to a high R2* in both in vivo and ex vivo T2*-weighted images compared to DCs. On histological analysis FTH-DCs migrated to the subcapsular sinus and the T cell zone of LN, where they highly expressed CD25 to bind and stimulate T cells. Our study addresses the feasibility of FTH as an MRI reporter gene to track DCs migration into LNs without alteration of their inherent properties. This study suggests that FTH-based MRI could be a useful technique to longitudinally monitor DCs and evaluate the therapeutic efficacy of DC-based vaccines.
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Affiliation(s)
- Hoe Suk Kim
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Korea
| | - Jisu Woo
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Korea
| | - Jae Hoon Lee
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Korea
| | - Hyun Jung Joo
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Korea
| | - YoonSeok Choi
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Korea
- Department of Biomedical Science, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, Korea
| | - Hyeonjin Kim
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Korea
- Department of Biomedical Science, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, Korea
| | - Woo Kyung Moon
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, Korea
- Department of Biomedical Science, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, Korea
- * E-mail: (WKM); (SJK)
| | - Seung Ja Kim
- Department of Radiology, Seoul Metropolitan Government Seoul National University, Boramae Medical Center, 20 Boramae-ro, Dongjag-gu, Seoul, Korea
- * E-mail: (WKM); (SJK)
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Kim HS, Woo J, Choi Y, Hwang EH, Choi SK, Cho KW, Moon WK. Noninvasive MRI and multilineage differentiation capability of ferritin-transduced human mesenchymal stem cells. NMR IN BIOMEDICINE 2015; 28:168-179. [PMID: 25448225 DOI: 10.1002/nbm.3236] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 10/14/2014] [Accepted: 10/25/2014] [Indexed: 06/04/2023]
Abstract
Molecular imaging can be a breakthrough tool for the investigation of the behavior and ultimate feasibility of transplanted human mesenchymal stem cells (hMSCs) inside the body, and for the development of guidelines and recommendations based on the treatment and evaluation of stem cell therapy for patients. The goals of this study were to evaluate the multilineage differentiation ability of hMSCs expressing an MRI reporter, human ferritin heavy chain (FTH) and to investigate the feasibility of using FTH-based MRI to provide noninvasive imaging of transplanted hMSCs. The transduction of FTH and green fluorescence protein (GFP) did not influence the expression of the mesenchymal stem cell surface markers (CD29+/CD105+/CD34-/CD45-) or the self-renewal marker genes [octamer-binding transcription factor 4 (OCT-4) and SRY (sex determining region Y)-box 2 (Sox-2)], cell viability, migration ability and the release of cytokines [interleukin-5 (IL-5), IL-10, IL-12p70, tumor necrosis factor-α (TNF-α)]. FTH-hMSCs retained the capacity to differentiate into adipogenic, chondrogenic, osteogenic and neurogenic lineages. The transduction of FTH led to a significant enhancement in cellular iron storage capacity and caused hypointensity and a significant increase in R2 * values of FTH-hMSC-collected phantoms and FTH-hMSC-transplanted sites of the brain, as shown by in vitro and in vivo MRI performed at 9.4 T, compared with control hMSCs. This study revealed no differences in biological characteristics between hMSCs and FTH-hMSCs and, therefore, these cells could be used for noninvasive monitoring with MRI during stem cell therapy for brain injury. Our study suggests the use of FTH for in vivo long-term tracking and ultimate fate of hMSCs without alteration of their characteristics and multidifferentiation potential.
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Affiliation(s)
- Hoe Suk Kim
- Department of Radiology, Seoul National University Hospital, Seoul, South Korea
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Cho HR, Kim DH, Kim D, Doble P, Bishop D, Hare D, Park CK, Moon WK, Han MH, Choi SH. Malignant Glioma: MR Imaging by Using 5-Aminolevulinic Acid in an Animal Model. Radiology 2014; 272:720-30. [DOI: 10.1148/radiol.14131459] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bierry G, Dietemann JL. Imaging evaluation of inflammation in the musculoskeletal system: current concepts and perspectives. Skeletal Radiol 2013; 42:1347-59. [PMID: 23685709 DOI: 10.1007/s00256-013-1636-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 04/08/2013] [Accepted: 04/22/2013] [Indexed: 02/02/2023]
Abstract
Inflammation is the non-specific stereotyped reaction of the musculoskeletal system to various types of aggression, such as infection, tumor, autoimmune diseases, or trauma. Precise evaluation and, increasingly, reliable quantification of inflammation are now key factors for optimal patient management, as targeted therapies (e.g., anti-angiogenesis, anti-macrophages, anti-cytokines) are emerging as everyday drugs. In current practice, inflammation is evaluated mostly using MRI and US on the basis of its non-specific extracellular component due to the increased volume of free water. Inflamed tissue is described as areas of low T1 signal and high T2 signal on magnetic resonance imaging or as hypoechogenic areas on ultrasound imaging, and the evaluation of the increased tissue vascularity can be performed using gadolinium-enhanced MRI or power Doppler US. Emerging new imaging tools, regrouped under the label "cellular and molecular imaging" and defined as the in vivo characterization and measurement of biologic processes at the cellular and molecular level, demonstrate the possible shift of medical imaging from a macroscopic and non-specific level to a microscopic and targeted scale. Cellular and molecular imaging now allows the investigation of specific pathways involved in inflammation (e.g., angiogenesis, cell proliferation, and recruitment, proteases generation, metabolism, gene expression). PET and SPECT imaging are the most commonly used "molecular" imaging modalities, but recent progress in MR, US, and optical imaging has been made. In the future, those techniques might enable a detection of inflammation at its very early stage, its quantification through the definition of biomarkers, and possibly demonstrate the response to therapy at molecular and cellular levels.
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Affiliation(s)
- Guillaume Bierry
- Department of Radiology, University Hospital of Strasbourg, 10 Avenue Molière, 67098 Strasbourg, France.
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Cho EY, Kim SH, Yoon JH, Lee Y, Lim YJ, Kim SJ, Baek HJ, Eun CK. Apparent diffusion coefficient for discriminating metastatic from non-metastatic lymph nodes in primary rectal cancer. Eur J Radiol 2013; 82:e662-8. [PMID: 24016824 DOI: 10.1016/j.ejrad.2013.08.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/26/2013] [Accepted: 08/01/2013] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To investigate whether the apparent diffusion coefficient (ADC) could be used to discriminate metastatic from non-metastatic lymph nodes (LNs) in patients with primary rectal cancer. METHODS This study investigated 34 patients (male: 12, female: 22, mean: 62.7, range: 37-82) who underwent 1.5-T MRI with diffusion-weighted imaging (DWI) and subsequent surgical resection. A blinded radiologist measured the ADC value in each regional LN after referring to the T2-weighted images and DWI. The t-test was used to compare the mean ADC values of the metastatic and non-metastatic LNs. A ROC analysis was performed to calculate the diagnostic performance and obtain the optimal cut-off. The histopathological results were used as the reference standard. RESULTS 114 LNs (46 metastatic and 68 non-metastatic) were matched and analyzed. The mean ADC of the metastatic LNs was significantly lower than that of the non-metastatic LNs (0.9 ± 0.15 × 10(-3) mm(2)/s; 1.1 ± 0.22 × 10(-3) mm(2)/s, P<0.0001). The area under the ROC curve was 0.734 (95% confidence interval, 0.644-0.812). When an ADC value of 1.0 × 10(-3) mm(2)/s was used as the cut-off, a maximum accuracy of 72% was calculated (sensitivity, 78%; specificity, 67%). CONCLUSIONS Although ADC could be used to discriminate metastatic from non-metastatic LNs, the diagnostic accuracy is approximately 70%.
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Affiliation(s)
- Een Young Cho
- Department of Radiology, Inje University College of Medicine, Haeundae Paik Hospital, Haeundae-ro 875, Haeundae-gu, Busan 612 030, Republic of Korea.
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Vandsburger MH, Radoul M, Cohen B, Neeman M. MRI reporter genes: applications for imaging of cell survival, proliferation, migration and differentiation. NMR IN BIOMEDICINE 2013; 26:872-84. [PMID: 23225197 PMCID: PMC3713407 DOI: 10.1002/nbm.2869] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/18/2012] [Accepted: 08/24/2012] [Indexed: 05/05/2023]
Abstract
Molecular imaging strives to detect molecular events at the level of the whole organism. In some cases, the molecule of interest can be detected either directly or with targeted contrast media. However many genes and proteins and particularly those located in intracellular compartments are not accessible for targeted agents. The transcriptional regulation of these genes can nevertheless be detected, although indirectly, using reporter gene encoding for readily detectable proteins. Such reporter proteins can be expressed in the tissue of interest by genetically introducing the reporter gene in the target cells. Imaging of reporter genes has become a powerful tool in modern biomedical research. Typically, expression of fluorescent and bioluminescent proteins and the reaction product of expressed enzymes and exogenous substrates were examined using in vitro histological methods and in vivo whole body imaging methods. Recent advances in MRI reporter gene methods raised the possibility that MRI could become a powerful tool for concomitant high-resolution anatomical and functional imaging and for imaging of reporter gene activity. An immediate application of MRI reporter gene methods was by monitoring gene expression patterns in gene therapy and in vivo imaging of the survival, proliferation, migration and differentiation of pluripotent and multipotent cells used in cell-based regenerative therapies for cancer, myocardial infarction and neural degeneration. In this review, we characterized a variety of MRI reporter gene methods based on their applicability to report cell survival/proliferation, migration and differentiation. In particular, we discussed which methods were best suited for translation to clinical use in regenerative therapies.
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Affiliation(s)
| | - Marina Radoul
- Department of Biological Regulation, Weizmann Institute of Science
| | - Batya Cohen
- Department of Biological Regulation, Weizmann Institute of Science
| | - Michal Neeman
- Department of Biological Regulation, Weizmann Institute of Science
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Fan K, Gao L, Yan X. Human ferritin for tumor detection and therapy. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2013; 5:287-98. [PMID: 23606622 DOI: 10.1002/wnan.1221] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Ferritin, a major iron storage protein found in most living organisms, is composed of a 24-subunit protein cage with a hollow interior cavity. Serum ferritin serves as a critical marker to detect total body iron status. However, recent research reveals a number of novel functions of ferritin besides iron storage; for example, a ferritin receptor, transferrin receptor 1 (TfR1), has been identified and serum ferritin levels are found to be elevated in tumors. A particular new finding is that magnetoferritin nanoparticles, biomimetically synthesized using H-chain ferritin to form a 24-subunit cage with an iron oxide core, possess intrinsic dual functionality, the protein shell specifically targeting tumors and the iron oxide core catalyzing peroxidase substrates to produce a color reaction allowing visualization of tumor tissues. Here we attempt to summarize current research on ferritin, particularly newly identified functions related to tumors, in order to address current challenges and highlight future directions.
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Affiliation(s)
- Kelong Fan
- Key Laboratory of Protein and Peptide Pharmaceuticals, CAS-University of Tokyo Joint Laboratory of Structural Virology and Immunology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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Noninvasive identification of viable cell populations in docetaxel-treated breast tumors using ferritin-based magnetic resonance imaging. PLoS One 2013; 8:e52931. [PMID: 23301003 PMCID: PMC3534651 DOI: 10.1371/journal.pone.0052931] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 11/22/2012] [Indexed: 12/01/2022] Open
Abstract
Background Cancer stem cells (CSCs) are highly tumorigenic and are responsible for tumor progression and chemoresistance. Noninvasive imaging methods for the visualization of CSC populations within tumors in vivo will have a considerable impact on the development of new CSC-targeting therapeutics. Methodology/Principal Findings In this study, human breast cancer stem cells (BCSCs) transduced with dual reporter genes (human ferritin heavy chain [FTH] and enhanced green fluorescence protein [EGFP]) were transplanted into NOD/SCID mice to allow noninvasive tracking of BCSC-derived populations. No changes in the properties of the BCSCs were observed due to ferritin overexpression. Magnetic resonance imaging (MRI) revealed significantly different signal intensities (R2* values) between BCSCs and FTH-BCSCs in vitro and in vivo. In addition, distinct populations of pixels with high R2* values were detected in docetaxel-treated FTH-BCSC tumors compared with control tumors, even before the tumor sizes changed. Histological analysis revealed that areas showing high R2* values in docetaxel-treated FTH-BCSC tumors by MRI contained EGFP+/FTH+ viable cell populations with high percentages of CD44+/CD24− cells. Conclusions/Significance These findings suggest that ferritin-based MRI, which provides high spatial resolution and tissue contrast, can be used as a reliable method to identify viable cell populations derived from BCSCs after chemotherapy and may serve as a new tool to monitor the efficacy of CSC-targeting therapies in vivo.
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Quantification of HSV-1-mediated expression of the ferritin MRI reporter in the mouse brain. Gene Ther 2012; 20:589-96. [PMID: 22996196 DOI: 10.1038/gt.2012.70] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The development of effective strategies for gene therapy has been hampered by difficulties verifying transgene delivery in vivo and quantifying gene expression non-invasively. Magnetic resonance imaging (MRI) offers high spatial resolution and three-dimensional views, without tissue depth limitations. The iron-storage protein ferritin is a prototype MRI gene reporter. Ferritin forms a paramagnetic ferrihydrite core that can be detected by MRI via its effect on the local magnetic field experienced by water protons. In an effort to better characterize the ferritin reporter for central nervous system applications, we expressed ferritin in the mouse brain in vivo using a neurotropic herpes simplex virus type 1 (HSV-1). We computed three-dimensional maps of MRI transverse relaxation rates in the mouse brain with ascending doses of ferritin-expressing HSV-1. We established that the transverse relaxation rates correlate significantly to the number of inoculated infectious particles. Our results are potentially useful for quantitatively assessing limitations of ferritin reporters for gene therapy applications.
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Lee SW, Lee SH, Biswal S. Magnetic resonance reporter gene imaging. Theranostics 2012; 2:403-12. [PMID: 22539936 PMCID: PMC3337732 DOI: 10.7150/thno.3634] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 03/09/2012] [Indexed: 11/05/2022] Open
Abstract
Molecular imaging has undergone an explosive advancement in recent years, due to the tremendous research efforts made to understand and visualize biological processes. Molecular imaging by definition assesses cellular and molecular processes in living subjects, with the targets of following metabolic, genomic, and proteomic events. Furthermore, reporter gene imaging plays a central role in this field. Many different approaches have been used to visualize genetic events in living subjects, such as, optical, radionuclide, and magnetic resonance imaging. Compared with the other techniques, magnetic resonance (MR)-based reporter gene imaging has not occupied center stage, despite its superior three-dimensional depictions of anatomical details. In this article, the authors review the principles and applications of various types of MR reporter gene imaging technologies and discuss their advantages and disadvantages.
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Is there a path beyond BOLD? Molecular imaging of brain function. Neuroimage 2012; 62:1208-15. [PMID: 22406355 DOI: 10.1016/j.neuroimage.2012.02.076] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 02/18/2012] [Accepted: 02/27/2012] [Indexed: 12/20/2022] Open
Abstract
The dependence of BOLD on neuro-vascular coupling leaves it many biological steps removed from direct monitoring of neural function. MRI based approaches have been developed aimed at reporting more directly on brain function. These include: manganese enhanced MRI as a surrogate for calcium ion influx; agents responsive to calcium concentrations; approaches to measure membrane potential; agents to measure neurotransmitters; and strategies to measure gene expression. This work has led to clever design of molecular imaging tools and many contributions to studies of brain function in animal models. However, a robust approach that has potential to get MRI closer to neurons in the human brain has not yet emerged.
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