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Smith JT, Sinsuebphon N, Rudkouskaya A, Michalet X, Intes X, Barroso M. In vivo quantitative FRET small animal imaging: Intensity versus lifetime-based FRET. BIOPHYSICAL REPORTS 2023; 3:100110. [PMID: 37251213 PMCID: PMC10209493 DOI: 10.1016/j.bpr.2023.100110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023]
Abstract
Förster resonance energy transfer (FRET) microscopy is used in numerous biophysical and biomedical applications to monitor inter- and intramolecular interactions and conformational changes in the 2-10 nm range. FRET is currently being extended to in vivo optical imaging, its main application being in quantifying drug-target engagement or drug release in animal models of cancer using organic dye or nanoparticle-labeled probes. Herein, we compared FRET quantification using intensity-based FRET (sensitized emission FRET analysis with the three-cube approach using an IVIS imager) and macroscopic fluorescence lifetime (MFLI) FRET using a custom system using a time-gated-intensified charge-coupled device, for small animal optical in vivo imaging. The analytical expressions and experimental protocols required to quantify the product f D E of the FRET efficiency E and the fraction of donor molecules involved in FRET, f D , are described in detail for both methodologies. Dynamic in vivo FRET quantification of transferrin receptor-transferrin binding was acquired in live intact nude mice upon intravenous injection of a near-infrared-labeled transferrin FRET pair and benchmarked against in vitro FRET using hybridized oligonucleotides. Even though both in vivo imaging techniques provided similar dynamic trends for receptor-ligand engagement, we demonstrate that MFLI-FRET has significant advantages. Whereas the sensitized emission FRET approach using the IVIS imager required nine measurements (six of which are used for calibration) acquired from three mice, MFLI-FRET needed only one measurement collected from a single mouse, although a control mouse might be needed in a more general situation. Based on our study, MFLI therefore represents the method of choice for longitudinal preclinical FRET studies such as that of targeted drug delivery in intact, live mice.
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Affiliation(s)
- Jason T. Smith
- Center for Modeling, Simulation and Imaging in Medicine (CeMSIM), Rensselaer Polytechnic Institute, Troy, New York
| | - Nattawut Sinsuebphon
- Center for Modeling, Simulation and Imaging in Medicine (CeMSIM), Rensselaer Polytechnic Institute, Troy, New York
| | - Alena Rudkouskaya
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Xavier Michalet
- Department of Chemistry & Biochemistry, University of California at Los Angeles, Los Angeles, California
| | - Xavier Intes
- Center for Modeling, Simulation and Imaging in Medicine (CeMSIM), Rensselaer Polytechnic Institute, Troy, New York
| | - Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
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Smith JT, Sinsuebphon N, Rudkouskaya A, Michalet X, Intes X, Barroso M. in vivo quantitative FRET small animal imaging: intensity versus lifetime-based FRET. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.24.525411. [PMID: 36747671 PMCID: PMC9900789 DOI: 10.1101/2023.01.24.525411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Förster Resonance Energy Transfer (FRET) microscopy is used in numerous biophysical and biomedical applications to monitor inter- and intramolecular interactions and conformational changes in the 2-10 nm range. FRET is currently being extended to in vivo optical imaging, its main application being in quantifying drug-target engagement or drug release in animal models of cancer using organic dye or nanoparticle-labeled probes. Herein, we compared FRET quantification using intensity-based FRET (sensitized emission FRET analysis with the 3-cube approach using an IVIS imager) and macroscopic fluorescence lifetime (MFLI) FRET using a custom system using a time-gated ICCD, for small animal optical in vivo imaging. The analytical expressions and experimental protocols required to quantify the product f D E of the FRET efficiency E and the fraction of donor molecules involved in FRET, f D , are described in detail for both methodologies. Dynamic in vivo FRET quantification of transferrin receptor-transferrin binding was acquired in live intact nude mice upon intravenous injection of near infrared-labeled transferrin FRET pair and benchmarked against in vitro FRET using hybridized oligonucleotides. Even though both in vivo imaging techniques provided similar dynamic trends for receptor-ligand engagement, we demonstrate that MFLI FRET has significant advantages. Whereas the sensitized emission FRET approach using the IVIS imager required 9 measurements (6 of which are used for calibration) acquired from three mice, MFLI FRET needed only one measurement collected from a single mouse, although a control mouse might be needed in a more general situation. Based on our study, MFLI therefore represents the method of choice for longitudinal preclinical FRET studies such as that of targeted drug delivery in intact, live mice.
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Affiliation(s)
- Jason T. Smith
- Center for Modeling, Simulation and Imaging in Medicine (CeMSIM), Rensselaer Polytechnic Institute, Troy, NY 12180, USA
- Present address: Elephas, 1 Erdman Pl., Madison, WI 53705, USA
| | - Nattawut Sinsuebphon
- Center for Modeling, Simulation and Imaging in Medicine (CeMSIM), Rensselaer Polytechnic Institute, Troy, NY 12180, USA
- Present address: Assistive Technology and Medical Devices Research Center, National Science and Technology Development Agency, 12120 Pathum Thani, Thailand
| | - Alena Rudkouskaya
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA
| | - Xavier Michalet
- Department of Chemistry & Biochemistry, University of California at Los Angeles, Los Angeles, California, CA 90095, USA
| | - Xavier Intes
- Center for Modeling, Simulation and Imaging in Medicine (CeMSIM), Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA
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Ochoa M, Rudkouskaya A, Smith JT, Intes X, Barroso M. Macroscopic Fluorescence Lifetime Imaging for Monitoring of Drug-Target Engagement. Methods Mol Biol 2022; 2394:837-856. [PMID: 35094361 PMCID: PMC8941982 DOI: 10.1007/978-1-0716-1811-0_44] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Precision medicine promises to improve therapeutic efficacy while reducing adverse effects, especially in oncology. However, despite great progresses in recent years, precision medicine for cancer treatment is not always part of routine care. Indeed, the ability to specifically tailor therapies to distinct patient profiles requires still significant improvements in targeted therapy development as well as decreases in drug treatment failures. In this regard, preclinical animal research is fundamental to advance our understanding of tumor biology, and diagnostic and therapeutic response. Most importantly, the ability to measure drug-target engagement accurately in live and intact animals is critical in guiding the development and optimization of targeted therapy. However, a major limitation of preclinical molecular imaging modalities is their lack of capability to directly and quantitatively discriminate between drug accumulation and drug-target engagement at the pathological site. Recently, we have developed Macroscopic Fluorescence Lifetime Imaging (MFLI) as a unique feature of optical imaging to quantitate in vivo drug-target engagement. MFLI quantitatively reports on nanoscale interactions via lifetime-sensing of Förster Resonance Energy Transfer (FRET) in live, intact animals. Hence, MFLI FRET acts as a direct reporter of receptor dimerization and target engagement via the measurement of the fraction of labeled-donor entity undergoing binding to its respective receptor. MFLI is expected to greatly impact preclinical imaging and also adjacent fields such as image-guided surgery and drug development.
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Affiliation(s)
- Marien Ochoa
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Alena Rudkouskaya
- Department of Cellular and Molecular Physiology, Albany Medical College, Albany, NY, USA
| | - Jason T Smith
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Margarida Barroso
- Department of Cellular and Molecular Physiology, Albany Medical College, Albany, NY, USA.
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Tubbesing K, Khoo TC, Bahreini Jangjoo S, Sharikova A, Barroso M, Khmaladze A. Iron-binding cellular profile of transferrin using label-free Raman hyperspectral imaging and singular value decomposition (SVD). Free Radic Biol Med 2021; 169:416-424. [PMID: 33930515 PMCID: PMC8667008 DOI: 10.1016/j.freeradbiomed.2021.04.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/12/2021] [Accepted: 04/21/2021] [Indexed: 01/07/2023]
Abstract
Serum transferrin (Tf) is the essential iron transport protein in the body. Transferrin is responsible for the sequestration of free iron in serum and the delivery of iron throughout the body and into cells, where iron is released inside a mildly acidified endosome. Altered iron distributions are associated with diseases such as iron-overload, cancer, and cardiovascular disease. The presence of free iron is linked to deleterious redox reactions, inside and outside cells and organelles. As Tf iron release is pH dependent, any changes in intraorganelle and extracellular pH, often associated with disease progression, could inhibit normal iron delivery or accelerate iron release in the wrong compartment. However, imaging approaches to monitor changes in the iron-bound state of Tf are lacking. Recently, Raman spectroscopy has been shown to measure iron-bound forms of Tf in solution, intact cells and tissue samples. Here, a biochemical Raman assay has been developed to identify iron-release from Tf following modification of chemical environment. Quantitative singular value decomposition (SVD) method has been applied to discriminate between iron-bound Tf samples during endocytic trafficking in intact cancer cells subjected to Raman hyperspectral confocal imaging. We demonstrate the strength of the SVD method to monitor pH-induced Tf iron-release using Raman hyperspectral imaging, providing the redox biology field with a novel tool that facilitates subcellular investigation of the iron-binding profile of transferrin in various disease models.
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Affiliation(s)
- Kate Tubbesing
- Physics Department, SUNY University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Ting Chean Khoo
- Physics Department, SUNY University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Shahab Bahreini Jangjoo
- Physics Department, SUNY University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Anna Sharikova
- Physics Department, SUNY University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, 47 New Scotland Avenue, Albany, NY, 12208, USA
| | - Alexander Khmaladze
- Physics Department, SUNY University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA.
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Quantification of Trastuzumab-HER2 Engagement In Vitro and In Vivo. Molecules 2020; 25:molecules25245976. [PMID: 33348564 PMCID: PMC7767145 DOI: 10.3390/molecules25245976] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/22/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
Human EGF Receptor 2 (HER2) is an important oncogene driving aggressive metastatic growth in up to 20% of breast cancer tumors. At the same time, it presents a target for passive immunotherapy such as trastuzumab (TZM). Although TZM has been widely used clinically since 1998, not all eligible patients benefit from this therapy due to primary and acquired drug resistance as well as potentially lack of drug exposure. Hence, it is critical to directly quantify TZM–HER2 binding dynamics, also known as cellular target engagement, in undisturbed tumor environments in live, intact tumor xenograft models. Herein, we report the direct measurement of TZM–HER2 binding in HER2-positive human breast cancer cells and tumor xenografts using fluorescence lifetime Forster Resonance Energy Transfer (FLI-FRET) via near-infrared (NIR) microscopy (FLIM-FRET) as well as macroscopy (MFLI-FRET) approaches. By sensing the reduction of fluorescence lifetime of donor-labeled TZM in the presence of acceptor-labeled TZM, we successfully quantified the fraction of HER2-bound and internalized TZM immunoconjugate both in cell culture and tumor xenografts in live animals. Ex vivo immunohistological analysis of tumors confirmed the binding and internalization of TZM–HER2 complex in breast cancer cells. Thus, FLI-FRET imaging presents a powerful analytical tool to monitor and quantify cellular target engagement and subsequent intracellular drug delivery in live HER2-positive tumor xenografts.
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Rudkouskaya A, Sinsuebphon N, Ochoa M, Chen SJ, Mazurkiewicz JE, Intes X, Barroso M. Multiplexed non-invasive tumor imaging of glucose metabolism and receptor-ligand engagement using dark quencher FRET acceptor. Theranostics 2020; 10:10309-10325. [PMID: 32929350 PMCID: PMC7481426 DOI: 10.7150/thno.45825] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/25/2020] [Indexed: 12/31/2022] Open
Abstract
Rationale: Following an ever-increased focus on personalized medicine, there is a continuing need to develop preclinical molecular imaging modalities to guide the development and optimization of targeted therapies. Near-Infrared (NIR) Macroscopic Fluorescence Lifetime Förster Resonance Energy Transfer (MFLI-FRET) imaging offers a unique method to robustly quantify receptor-ligand engagement in live intact animals, which is critical to assess the delivery efficacy of therapeutics. However, to date, non-invasive imaging approaches that can simultaneously measure cellular drug delivery efficacy and metabolic response are lacking. A major challenge for the implementation of concurrent optical and MFLI-FRET in vivo whole-body preclinical imaging is the spectral crowding and cross-contamination between fluorescent probes. Methods: We report on a strategy that relies on a dark quencher enabling simultaneous assessment of receptor-ligand engagement and tumor metabolism in intact live mice. Several optical imaging approaches, such as in vitro NIR FLI microscopy (FLIM) and in vivo wide-field MFLI, were used to validate a novel donor-dark quencher FRET pair. IRDye 800CW 2-deoxyglucose (2-DG) imaging was multiplexed with MFLI-FRET of NIR-labeled transferrin FRET pair (Tf-AF700/Tf-QC-1) to monitor tumor metabolism and probe uptake in breast tumor xenografts in intact live nude mice. Immunohistochemistry was used to validate in vivo imaging results. Results: First, we establish that IRDye QC-1 (QC-1) is an effective NIR dark acceptor for the FRET-induced quenching of donor Alexa Fluor 700 (AF700). Second, we report on simultaneous in vivo imaging of the metabolic probe 2-DG and MFLI-FRET imaging of Tf-AF700/Tf-QC-1 uptake in tumors. Such multiplexed imaging revealed an inverse relationship between 2-DG uptake and Tf intracellular delivery, suggesting that 2-DG signal may predict the efficacy of intracellular targeted delivery. Conclusions: Overall, our methodology enables for the first time simultaneous non-invasive monitoring of intracellular drug delivery and metabolic response in preclinical studies.
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Affiliation(s)
- Alena Rudkouskaya
- Department of Cellular and Molecular Physiology, Albany Medical College, Albany, NY 12208, USA
| | - Nattawut Sinsuebphon
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Marien Ochoa
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Sez-Jade Chen
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Joseph E. Mazurkiewicz
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA
| | - Xavier Intes
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Margarida Barroso
- Department of Cellular and Molecular Physiology, Albany Medical College, Albany, NY 12208, USA
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7
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Cao R, Wallrabe H, Siller K, Periasamy A. Optimization of FLIM imaging, fitting and analysis for auto-fluorescent NAD(P)H and FAD in cells and tissues. Methods Appl Fluoresc 2020; 8:024001. [PMID: 31972557 DOI: 10.1088/2050-6120/ab6f25] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Increasingly, the auto-fluorescent coenzymes NAD(P)H and FAD are being tracked by multi-photon fluorescence lifetime microscopy (FLIM) and used as versatile markers for changes in mammalian metabolism. The cellular redox state of different cell model systems, organoids and tissue sections is investigated in a range of pathologies where the metabolism is disrupted or reprogrammed; the latter is particularly relevant in cancer biology. Yet, the actual optimized process of acquiring images by FLIM, execute a correct lifetime fitting procedure and subsequent processing and analysis can be challenging for new users. Questions remain of how to optimize FLIM experiments, whether any potential photo-bleaching affects FLIM results and whether fixed specimens can be used in experiments. We have broken down the multi-step sequence into best-practice application of FLIM for NAD(P)H and FAD imaging, with images generated by a time-correlated-single-photon-counting (TCSPC) system, fitted with Becker & Hickl software and further processed with open-source ImageJ/Fiji and Python software.
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Affiliation(s)
- Ruofan Cao
- The W.M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, VA, United States of America
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Cao R, Wallrabe H, Periasamy A. Multiphoton FLIM imaging of NAD(P)H and FAD with one excitation wavelength. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-16. [PMID: 31920048 PMCID: PMC6951488 DOI: 10.1117/1.jbo.25.1.014510] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/12/2019] [Indexed: 05/07/2023]
Abstract
Two-photon fluorescence lifetime imaging microscopy (FLIM) is widely used to capture autofluorescence signals from cellular components to investigate dynamic physiological changes in live cells and tissues. Among these intrinsic fluorophores, nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and flavin adenine dinucleotide (FAD)-essential coenzymes in cellular respiration-have been used as intrinsic fluorescent biomarkers for metabolic states in cancer and other pathologies. Traditional FLIM imaging for NAD(P)H, FAD, and in particular fluorescence lifetime redox ratio (FLIRR) requires a sequential multiwavelength excitation to avoid spectral bleed-through (SBT). This sequential imaging complicates image acquisition, may introduce motion artifacts, and reduce temporal resolution. Testing several two-photon excitation wavelengths in combination with optimized emission filters, we have proved a FLIM imaging protocol, allowing simultaneous image acquisition with a single 800-nm wavelength excitation for NADH and FAD with negligible SBT. As a first step, standard NADH and FAD single and mixed solutions were tested that mimic biological sample conditions. After these optimization steps, the assay was applied to two prostate cancer live cell lines: African-American (AA) and Caucasian-American (LNCaP), used in our previous publications. FLIRR result shows that, in cells, the 800-nm two-photon excitation wavelength is suitable for NADH and FAD FLIM imaging with negligible SBT. While NAD(P)H signals are decreased, sufficient photons are present for accurate lifetime fitting and FAD signals are measurably increased at lower laser power, compared with the common 890-nm excitation conditions. This single wavelength excitation allows a simplification of NADH and FAD FLIM imaging data analysis, decreasing the total imaging time. It also avoids motion artifacts and increases temporal resolution. This simplified assay will also make it more suitable to be applied in a clinical setting.
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Affiliation(s)
- Ruofan Cao
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
| | - Horst Wallrabe
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
| | - Ammasi Periasamy
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
- University of Virginia, Department of Biomedical Engineering, Charlottesville, Virginia, United States
- Address all correspondence to Ammasi Periasamy, E-mail:
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Kingsley DM, Roberge CL, Rudkouskaya A, Faulkner DE, Barroso M, Intes X, Corr DT. Laser-based 3D bioprinting for spatial and size control of tumor spheroids and embryoid bodies. Acta Biomater 2019; 95:357-370. [PMID: 30776506 PMCID: PMC7171976 DOI: 10.1016/j.actbio.2019.02.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/08/2019] [Accepted: 02/12/2019] [Indexed: 12/17/2022]
Abstract
3D multicellular aggregates, and more advanced organotypic systems, have become central tools in recent years to study a wide variety of complex biological processes. Most notably, these model systems have become mainstream within oncology (multicellular tumor spheroids) and regenerative medicine (embryoid bodies) research. However, the biological behavior of these in vitro tissue surrogates is extremely sensitive to their aggregate size and geometry. Indeed, both of these geometrical parameters are key in producing pathophysiological gradients responsible for cellular and structural heterogeneity, replicating in vivo observations. Moreover, the fabrication techniques most widely used for producing these models lack the ability to accurately control cellular spatial location, an essential component for regulating homotypic and heterotypic cell signaling. Herein, we report on a 3D bioprinting technique, laser direct-write (LDW), that enables precise control of both spatial patterning and size of cell-encapsulating microbeads. The generated cell-laden beads are further processed into core-shelled structures, allowing for the growth and formation of self-contained, self-aggregating cells (e.g., breast cancer cells, embryonic stem cells). Within these structures we demonstrate our ability to produce multicellular tumor spheroids (MCTSs) and embryoid bodies (EBs) with well-controlled overall size and shape, that can be designed on demand. Furthermore, we investigated the impact of aggregate size on the uptake of a commonly employed ligand for receptor-mediated drug delivery, Transferrin, indicating that larger tumor spheroids exhibit greater spatial heterogeneity in ligand uptake. Taken together, these findings establish LDW as a versatile biomanufacturing platform for bioprinting and patterning core-shelled structures to generate size-controlled 3D multicellular aggregates. STATEMENT OF SIGNIFICANCE: Multicellular 3D aggregates are powerful in vitro models used to study a wide variety of complex biological processes, particularly within oncology and regenerative medicine. These tissue surrogates are fabricated using environments that encourage cellular self-assembly. However, specific applications require control of aggregate size and position to recapitulate key in vivo parameters (e.g., pathophysiological gradients and homotypic/heterotypic cell signaling). Herein, we demonstrate the ability to create and spatially pattern size-controlled embryoid bodies and tumor spheroids, using laser-based 3D bioprinting. Furthermore, we investigated the effect of tumor spheroid size on internalization of Transferrin, a common ligand for targeted therapy, finding greater spatial heterogeneity in our large aggregates. Overall, this technique offers incredible promise and flexibility for fabricating idealized 3D in vitro models.
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Affiliation(s)
- David M Kingsley
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - Cassandra L Roberge
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - Alena Rudkouskaya
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA.
| | - Denzel E Faulkner
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA.
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
| | - David T Corr
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180, USA.
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10
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Xia Q, Huang J, Feng Q, Chen X, Liu X, Li X, Zhang T, Xiao S, Li H, Zhong Z, Xiao K. Size- and cell type-dependent cellular uptake, cytotoxicity and in vivo distribution of gold nanoparticles. Int J Nanomedicine 2019; 14:6957-6970. [PMID: 32021157 PMCID: PMC6717860 DOI: 10.2147/ijn.s214008] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/06/2019] [Indexed: 02/05/2023] Open
Abstract
Background Gold nanoparticles (AuNPs) have shown great promise in biomedical applications. However, the interaction of AuNPs with biological systems, its underlying mechanisms and influencing factors need to be further elucidated. Purpose The aim of this study was to systematically investigate the effects of particle size on the uptake and cytotoxicity of AuNPs in normal cells and cancer cells as well as their biological distribution in vivo. Results Our data demonstrated that the uptake of AuNPs increased in HepG2 cancer cells but decreased in L02 normal cells, with the increase of particle size (5-50 nm). In both cancer cells and normal cells, small (5 nm) AuNPs exhibited greater cytotoxicity than large ones (20 and 50 nm). Interestingly, 5 nm AuNPs induced both apoptosis and necrosis in HepG2 cells through the production of reactive oxygen species (ROS) and the activation of pro-caspase3, whereas it mainly induced necrosis in L02 cells through the overexpression of TLR2 and the release of IL-6 and IL-1a cytokines. Among them, 50 nm AuNPs showed the longest blood circulation and highest distribution in liver and spleen, and the treatment of 5 nm AuNPs but not 20 nm and 50 nm AuNPs resulted in the increase of neutrophils and slight hepatotoxicity in mice. Conclusion Our results indicate that the particle size of AuNPs and target cell type are critical determinants of cellular uptake, cytotoxicity and underlying mechanisms, and biological distribution in vivo, which deserves careful consideration in the future biomedical applications.
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Affiliation(s)
- Qiyue Xia
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China.,Toxicology Department, Sichuan Center for Disease Control and Prevention, Chengdu, Sichuan Province, China
| | - Jinxing Huang
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China
| | - Qiyi Feng
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China
| | - Xuanming Chen
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China
| | - Xinyi Liu
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China
| | - Xiaojie Li
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China
| | - Ting Zhang
- Laboratory of Nonhuman Primate Disease Modeling Research, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Shuwen Xiao
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China
| | - Hongxia Li
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China
| | - Zhihui Zhong
- Laboratory of Nonhuman Primate Disease Modeling Research, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Sichuan Kangcheng Biotech Co., Ltd, Chengdu, Sichuan Province, China
| | - Kai Xiao
- National Chengdu Center for Safety Evaluation of Drugs and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan Province, China.,Sichuan Kangcheng Biotech Co., Ltd, Chengdu, Sichuan Province, China
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11
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Chen SJ, Sinsuebphon N, Rudkouskaya A, Barroso M, Intes X, Michalet X. In vitro and in vivo phasor analysis of stoichiometry and pharmacokinetics using short-lifetime near-infrared dyes and time-gated imaging. JOURNAL OF BIOPHOTONICS 2019; 12:e201800185. [PMID: 30421551 PMCID: PMC6559731 DOI: 10.1002/jbio.201800185] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/08/2018] [Accepted: 11/11/2018] [Indexed: 05/22/2023]
Abstract
We introduce a simple new approach for time-resolved multiplexed analysis of complex systems using near-infrared (NIR) dyes, applicable to in vitro and in vivo studies. We show that fast and precise in vitro quantification of NIR fluorophores' short (subnanosecond) lifetime and stoichiometry can be done using phasor analysis, a computationally efficient and user-friendly representation of complex fluorescence intensity decays obtained with pulsed laser excitation and time-gated camera imaging. We apply this approach to the study of binding equilibria by Förster resonant energy transfer using two different model systems: primary/secondary antibody binding in vitro and ligand/receptor binding in cell cultures. We then extend it to dynamic imaging of the pharmacokinetics of transferrin engagement with the transferrin receptor in live mice, elucidating the kinetics of differential transferrin accumulation in specific organs, straightforwardly differentiating specific from nonspecific binding. Our method, implemented in a freely-available software, has the advantage of time-resolved NIR imaging, including better tissue penetration and background-free imaging, but simplifies and considerably speeds up data processing and interpretation, while remaining quantitative. These advances make this method attractive and of broad applicability for in vitro and in vivo molecular imaging and could be extended to applications as diverse as image-guided surgery or optical tomography.
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Affiliation(s)
- Sez-Jade Chen
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York
| | - Nattawut Sinsuebphon
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York
| | - Alena Rudkouskaya
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York
| | - Xavier Michalet
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California
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12
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Segmented cell analyses to measure redox states of autofluorescent NAD(P)H, FAD & Trp in cancer cells by FLIM. Sci Rep 2018; 8:79. [PMID: 29311591 PMCID: PMC5758727 DOI: 10.1038/s41598-017-18634-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/13/2017] [Indexed: 01/07/2023] Open
Abstract
Multiphoton FLIM microscopy offers many opportunities to investigate processes in live cells, tissue and animal model systems. For redox measurements, FLIM data is mostly published by cell mean values and intensity-based redox ratios. Our method is based entirely on FLIM parameters generated by 3-detector time domain microscopy capturing autofluorescent signals of NAD(P)H, FAD and novel FLIM-FRET application of Tryptophan and NAD(P)H-a2%/FAD-a1% redox ratio. Furthermore, image data is analyzed in segmented cells thresholded by 2 × 2 pixel Regions of Interest (ROIs) to separate mitochondrial oxidative phosphorylation from cytosolic glycolysis in a prostate cancer cell line. Hundreds of data points allow demonstration of heterogeneity in response to intervention, identity of cell responders to treatment, creating thereby different sub-populations. Histograms and bar charts visualize differences between cells, analyzing whole cell versus mitochondrial morphology data, all based on discrete ROIs. This assay method allows to detect subtle differences in cellular and tissue responses, suggesting an advancement over means-based analyses.
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13
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Hildebrandt N, Spillmann CM, Algar WR, Pons T, Stewart MH, Oh E, Susumu K, Díaz SA, Delehanty JB, Medintz IL. Energy Transfer with Semiconductor Quantum Dot Bioconjugates: A Versatile Platform for Biosensing, Energy Harvesting, and Other Developing Applications. Chem Rev 2016; 117:536-711. [DOI: 10.1021/acs.chemrev.6b00030] [Citation(s) in RCA: 457] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Niko Hildebrandt
- NanoBioPhotonics
Institut d’Electronique Fondamentale (I2BC), Université Paris-Saclay, Université Paris-Sud, CNRS, 91400 Orsay, France
| | | | - W. Russ Algar
- Department
of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Thomas Pons
- LPEM;
ESPCI Paris, PSL Research University; CNRS; Sorbonne Universités, UPMC, F-75005 Paris, France
| | | | - Eunkeu Oh
- Sotera Defense Solutions, Inc., Columbia, Maryland 21046, United States
| | - Kimihiro Susumu
- Sotera Defense Solutions, Inc., Columbia, Maryland 21046, United States
| | - Sebastian A. Díaz
- American Society for Engineering Education, Washington, DC 20036, United States
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14
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Abstract
Molecular medicine opens into a space of novel specific therapeutic agents: intracellularly active drugs such as peptides, proteins or nucleic acids, which are not able to cross cell membranes and enter the intracellular space on their own. Through the development of cell-targeted shuttles for specific delivery, this restriction in delivery has the potential to be converted into an advantage. On the one hand, due to the multiple extra- and intracellular barriers, such carrier systems need to be multifunctional. On the other hand, they must be precise and reproducibly manufactured due to pharmaceutical reasons. Here we review the design of precise sequence-defined delivery carriers, including solid-phase synthesized peptides and nonpeptidic oligomers, or nucleotide-based carriers such as aptamers and origami nanoboxes.
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15
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Omer T, Intes X, Hahn J. Temporal Data Set Reduction Based on D-Optimality for Quantitative FLIM-FRET Imaging. PLoS One 2015; 10:e0144421. [PMID: 26658308 PMCID: PMC4686107 DOI: 10.1371/journal.pone.0144421] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/18/2015] [Indexed: 12/13/2022] Open
Abstract
Fluorescence lifetime imaging (FLIM) when paired with Förster resonance energy transfer (FLIM-FRET) enables the monitoring of nanoscale interactions in living biological samples. FLIM-FRET model-based estimation methods allow the quantitative retrieval of parameters such as the quenched (interacting) and unquenched (non-interacting) fractional populations of the donor fluorophore and/or the distance of the interactions. The quantitative accuracy of such model-based approaches is dependent on multiple factors such as signal-to-noise ratio and number of temporal points acquired when sampling the fluorescence decays. For high-throughput or in vivo applications of FLIM-FRET, it is desirable to acquire a limited number of temporal points for fast acquisition times. Yet, it is critical to acquire temporal data sets with sufficient information content to allow for accurate FLIM-FRET parameter estimation. Herein, an optimal experimental design approach based upon sensitivity analysis is presented in order to identify the time points that provide the best quantitative estimates of the parameters for a determined number of temporal sampling points. More specifically, the D-optimality criterion is employed to identify, within a sparse temporal data set, the set of time points leading to optimal estimations of the quenched fractional population of the donor fluorophore. Overall, a reduced set of 10 time points (compared to a typical complete set of 90 time points) was identified to have minimal impact on parameter estimation accuracy (≈5%), with in silico and in vivo experiment validations. This reduction of the number of needed time points by almost an order of magnitude allows the use of FLIM-FRET for certain high-throughput applications which would be infeasible if the entire number of time sampling points were used.
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Affiliation(s)
- Travis Omer
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, United States of America
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, United States of America
| | - Juergen Hahn
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, United States of America
- Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, United States of America
- * E-mail:
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16
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Barroso M, Tucker H, Drake L, Nichol K, Drake JR. Antigen-B Cell Receptor Complexes Associate with Intracellular major histocompatibility complex (MHC) Class II Molecules. J Biol Chem 2015; 290:27101-27112. [PMID: 26400081 DOI: 10.1074/jbc.m115.649582] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Indexed: 01/09/2023] Open
Abstract
Antigen processing and MHC class II-restricted antigen presentation by antigen-presenting cells such as dendritic cells and B cells allows the activation of naïve CD4+ T cells and cognate interactions between B cells and effector CD4+ T cells, respectively. B cells are unique among class II-restricted antigen-presenting cells in that they have a clonally restricted antigen-specific receptor, the B cell receptor (BCR), which allows the cell to recognize and respond to trace amounts of foreign antigen present in a sea of self-antigens. Moreover, engagement of peptide-class II complexes formed via BCR-mediated processing of cognate antigen has been shown to result in a unique pattern of B cell activation. Using a combined biochemical and imaging/FRET approach, we establish that internalized antigen-BCR complexes associate with intracellular class II molecules. We demonstrate that the M1-paired MHC class II conformer, shown previously to be critical for CD4 T cell activation, is incorporated selectively into these complexes and loaded selectively with peptide derived from BCR-internalized cognate antigen. These results demonstrate that, in B cells, internalized antigen-BCR complexes associate with intracellular MHC class II molecules, potentially defining a site of class II peptide acquisition, and reveal a selective role for the M1-paired class II conformer in the presentation of cognate antigen. These findings provide key insights into the molecular mechanisms used by B cells to control the source of peptides charged onto class II molecules, allowing the immune system to mount an antibody response focused on BCR-reactive cognate antigen.
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Affiliation(s)
- Margarida Barroso
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208
| | - Heidi Tucker
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Lisa Drake
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Kathleen Nichol
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - James R Drake
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208.
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17
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Mazurkiewicz JE, Herrick-Davis K, Barroso M, Ulloa-Aguirre A, Lindau-Shepard B, Thomas RM, Dias JA. Single-molecule analyses of fully functional fluorescent protein-tagged follitropin receptor reveal homodimerization and specific heterodimerization with lutropin receptor. Biol Reprod 2015; 92:100. [PMID: 25761594 DOI: 10.1095/biolreprod.114.125781] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/02/2015] [Indexed: 01/27/2023] Open
Abstract
We have previously shown that the carboxyl terminus (cT) of human follicle-stimulating hormone (FSH, follitropin) receptor (FSHR) is clipped before insertion into the plasma membrane. Surprisingly, several different constructs of FSHR fluorescent fusion proteins (FSHR-FPs) failed to traffic to the plasma membrane. Subsequently, we discovered that substituting the extreme cT of luteinizing hormone (LH) receptor (LHR) to create an FSHR-LHRcT chimera has no effect on FSHR functionality. Therefore, we used this approach to create an FSHR-LHRcT-FP fusion. We found this chimeric FSHR-LHRcT-FP was expressed in HEK293 cells at levels similar to reported values for FSHR in human granulosa cells, bound FSH with high affinity, and transduced FSH binding to produce cAMP. Quantitative fluorescence resonance energy transfer (FRET) analysis of FSHR-LHRcT-YFP/FSHR-LHRcT-mCherry pairs revealed an average FRET efficiency of 12.9 ± 5.7. Advanced methods in single-molecule analyses were applied in order to ascertain the oligomerization state of the FSHR-LHRcT. Fluorescence correlation spectroscopy coupled with photon-counting histogram analyses demonstrated that the FSHR-LHRcT-FP fusion protein exists as a freely diffusing homodimer in the plasma membrane. A central question is whether LHR could oligomerize with FSHR, because both receptors are coexpressed in differentiated granulosa cells. Indeed, FRET analysis revealed an average FRET efficiency of 14.4 ± 7.5 when the FSHR-LHR cT-mCherry was coexpressed with LHR-YFP. In contrast, coexpression of a 5-HT2cVSV-YFP with FSHR-LHR cT-mCherry showed only 5.6 ± 3.2 average FRET efficiency, a value indistinguishable from the detection limit using intensity-based FRET methods. These data demonstrate that coexpression of FSHR and LHR can lead to heterodimerization, and we hypothesize that it is possible for this to occur during granulosa cell differentiation.
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Affiliation(s)
- Joseph E Mazurkiewicz
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York
| | | | - Margarida Barroso
- Center for Cardiovascular Science, Albany Medical College, Albany, New York
| | - Alfredo Ulloa-Aguirre
- Research Support Network, Instituto Nacional de Ciencias Médicas y Nutrición SZ-Universidad Nacional Autónoma de México, México D.F., México
| | - Barbara Lindau-Shepard
- Division of Genetic Disorders, Wadsworth Center, New York State Department of Health, Albany, New York
| | - Richard M Thomas
- Department of Biomedical Sciences, State University of New York at Albany, Albany, New York
| | - James A Dias
- Department of Biomedical Sciences, State University of New York at Albany, Albany, New York
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18
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Abstract
Optical imaging assays, especially fluorescence molecular assays, are minimally invasive if not completely noninvasive, and thus an ideal technique to be applied to live specimens. These fluorescence imaging assays are a powerful tool in biomedical sciences as they allow the study of a wide range of molecular and physiological events occurring in biological systems. Furthermore, optical imaging assays bridge the gap between the in vitro cell-based analysis of subcellular processes and in vivo study of disease mechanisms in small animal models. In particular, the application of Förster resonance energy transfer (FRET) and fluorescence lifetime imaging (FLIM), well-known techniques widely used in microscopy, to the optical imaging assay toolbox, will have a significant impact in the molecular study of protein-protein interactions during cancer progression. This review article describes the application of FLIM-FRET to the field of optical imaging and addresses their various applications, both current and potential, to anti-cancer drug delivery and cancer research.
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Affiliation(s)
- Shilpi Rajoria
- Albany Medical College, The Center for Cardiovascular Sciences, Albany, NY, 12208
| | - Lingling Zhao
- Rensselaer Polytechnic Institute, Biomedical imaging Center and Department of Biomedical Engineering, Troy, NY 12180
| | - Xavier Intes
- Rensselaer Polytechnic Institute, Biomedical imaging Center and Department of Biomedical Engineering, Troy, NY 12180
| | - Margarida Barroso
- Albany Medical College, The Center for Cardiovascular Sciences, Albany, NY, 12208
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19
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Szwed M, Kania KD, Jozwiak Z. Molecular damage caused by generation of reactive oxygen species in the redox cycle of doxorubicin-transferrin conjugate in human leukemia cell lines. Leuk Lymphoma 2014; 56:1475-83. [PMID: 25166006 DOI: 10.3109/10428194.2014.955022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In this study we focused on evaluation of the pro-oxidant properties of doxorubicin-transferrin (DOX-TRF) conjugate and its potency to damage macromolecules which are components of cellular compartments. Our experiments were performed on two human leukemia cell lines: K562 (chronic erythromyeloblastoid leukemia) and CCRF-CEM (acute lymphoblastic leukemia). We determined the reactive oxygen species (ROS) production and programmed cell death (PCD) induction by free DOX and its conjugate. Besides this, the lipid peroxidation and protein damage which can be provoked by DOX alone and DOX-TRF conjugate were assessed. ROS were produced in leukemia cells incubated with free DOX and DOX-TRF conjugate and the extent of apoptosis and necrosis was strongly dependent on the cell line, sensitivity to drug and time of incubation with the investigated compounds. The role of ROS in DOX-TRF conjugate-induced cell death was confirmed by the diminution effects of the antioxidant vitamin C.
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Affiliation(s)
- Marzena Szwed
- Department of Thermobiology, Faculty of Biology and Environmental Protection, University of Lodz , Lodz , Poland
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20
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Omer T, Zhao L, Intes X, Hahn J. Reduced temporal sampling effect on accuracy of time-domain fluorescence lifetime Förster resonance energy transfer. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:086023. [PMID: 25166472 PMCID: PMC4147194 DOI: 10.1117/1.jbo.19.8.086023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 07/30/2014] [Indexed: 05/04/2023]
Abstract
Fluorescence lifetime imaging (FLIM) aims at quantifying the exponential decay rate of fluorophores to yield lifetime maps over the imaged sample. When combined with Förster resonance energy transfer (FRET), the technique can be used to indirectly sense interactions at the nanoscale such as protein–protein interactions, protein–DNA interactions, and protein conformational changes. In the case of FLIM-FRET, the fluorescence intensity decays are fitted to a biexponential model in order to estimate the lifetime and fractional amplitude coefficients of each component of the population of the donor fluorophore (quenched and nonquenched). Numerous time data points, also called temporal or time gates, are typically employed for accurately estimating the model parameters, leading to lengthy acquisition times and significant computational demands. This work investigates the effect of the number and location of time gates on model parameter estimation accuracy. A detailed model of a FLIM-FRET imaging system is used for the investigation, and the simulation outcomes are validated with in vitro and in vivo experimental data. In all cases investigated, it is found that 10 equally spaced time gates allow robust estimation of model-based parameters with accuracy similar to that of full temporal datasets (90 gates).
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Affiliation(s)
- Travis Omer
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180, United States
| | - Lingling Zhao
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180, United States
| | - Xavier Intes
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180, United States
| | - Juergen Hahn
- Rensselaer Polytechnic Institute, Departments of Biomedical Engineering and Chemical & Biological Engineering, 110 8th Street, Troy, New York 12180, United States
- Address all correspondence to: Juergen Hahn, E-mail:
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21
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Spillmann CM, Naciri J, Algar WR, Medintz IL, Delehanty JB. Multifunctional liquid crystal nanoparticles for intracellular fluorescent imaging and drug delivery. ACS NANO 2014; 8:6986-6997. [PMID: 24979226 DOI: 10.1021/nn501816z] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A continuing goal of nanoparticle (NP)-mediated drug delivery (NMDD) is the simultaneous improvement of drug efficacy coupled with tracking of the intracellular fate of the nanoparticle delivery vehicle and its drug cargo. Here, we present a robust multifunctional liquid crystal NP (LCNP)-based delivery system that affords facile intracellular fate tracking coupled with the efficient delivery and modulation of the anticancer therapeutic doxorubicin (Dox), employed here as a model drug cargo. The LCNPs consist of (1) a liquid crystal cross-linking agent, (2) a homologue of the organic chromophore perylene, and (3) a polymerizable surfactant containing a carboxylate headgroup. The NP core provides an environment to both incorporate fluorescent dye for spectrally tuned particle tracking and encapsulation of amphiphilic and/or hydrophobic agents for intracellular delivery. The carboxylate head groups enable conjugation to biologicals to facilitate the cellular uptake of the particles. Upon functionalization of the NPs with transferrin, we show the ability to differentially label the recycling endocytic pathway in HEK 293T/17 cells in a time-resolved manner with minimal cytotoxicity and with superior dye photostability compared to traditional organic fluorophores. Further, when passively loaded with Dox, the NPs mediate the rapid uptake and subsequent sustained release of Dox from within endocytic vesicles. We demonstrate the ability of the LCNPs to simultaneously serve as both an efficient delivery vehicle for Dox as well as a modulator of the drug's cytotoxicity. Specifically, the delivery of Dox as a LCNP conjugate results in a ∼40-fold improvement in its IC50 compared to free Dox in solution. Cumulatively, our results demonstrate the utility of the LCNPs as an effective nanomaterial for simultaneous cellular imaging, tracking, and delivery of drug cargos.
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Affiliation(s)
- Christopher M Spillmann
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory , 4555 Overlook Avenue Southwest, Washington, D.C., 20375, United States
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22
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Affiliation(s)
- Ammasi Periasamy
- University of Virginia, W.M. Keck Center for Cellular Imaging, Charlottesville, VA, USA.
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23
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Abe K, Zhao L, Periasamy A, Intes X, Barroso M. Non-invasive in vivo imaging of near infrared-labeled transferrin in breast cancer cells and tumors using fluorescence lifetime FRET. PLoS One 2013; 8:e80269. [PMID: 24278268 PMCID: PMC3836976 DOI: 10.1371/journal.pone.0080269] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 10/11/2013] [Indexed: 12/05/2022] Open
Abstract
The conjugation of anti-cancer drugs to endogenous ligands has proven to be an effective strategy to enhance their pharmacological selectivity and delivery towards neoplasic tissues. Since cell proliferation has a strong requirement for iron, cancer cells express high levels of transferrin receptors (TfnR), making its ligand, transferrin (Tfn), of great interest as a delivery agent for therapeutics. However, a critical gap exists in the ability to non-invasively determine whether drugs conjugated to Tfn are internalized into target cells in vivo. Due to the enhanced permeability and retention (EPR) effect, it remains unknown whether these Tfn-conjugated drugs are specifically internalized into cancer cells or are localized non-specifically as a result of a generalized accumulation of macromolecules near tumors. By exploiting the dimeric nature of the TfnR that binds two molecules of Tfn in close proximity, we utilized a Förster Resonance Energy Transfer (FRET) based technique that can discriminate bound and internalized Tfn from free, soluble Tfn. In order to non-invasively visualize intracellular amounts of Tfn in tumors through live animal tissues, we developed a novel near infrared (NIR) fluorescence lifetime FRET imaging technique that uses an active wide-field time gated illumination platform. In summary, we report that the NIR fluorescence lifetime FRET technique is capable of non-invasively detecting bound and internalized forms of Tfn in cancer cells and tumors within a live small animal model, and that our results are quantitatively consistent when compared to well-established intensity-based FRET microscopy methods used in in vitro experiments.
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Affiliation(s)
- Ken Abe
- Albany Medical College, The Center for Cardiovascular Sciences, Albany, New York, United States of America
| | - Lingling Zhao
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Jonsson Engineering Center Troy, New York, United States of America
| | - Ammasi Periasamy
- W. M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia, United States of America
| | - Xavier Intes
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Jonsson Engineering Center Troy, New York, United States of America
| | - Margarida Barroso
- Albany Medical College, The Center for Cardiovascular Sciences, Albany, New York, United States of America
- * E-mail:
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