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Pal R, K M, Matsui A, Kang H, Morita S, Taniguchi H, Kobayashi T, Morita A, Choi HS, Duda DG, Kumar ATN. In vivo quantification of programmed death-ligand-1 expression heterogeneity in tumors using fluorescence lifetime imaging. RESEARCH SQUARE 2023:rs.3.rs-3222037. [PMID: 37961361 PMCID: PMC10635296 DOI: 10.21203/rs.3.rs-3222037/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Cancer patient selection for immunotherapy is often based on programmed death-ligand-1 (PD-L1) expression as a biomarker. PD-L1 expression is currently quantified using immunohistochemistry, which can only provide snapshots of PD-L1 expression status in microscopic regions of ex vivo specimens. In vivo imaging using targeted agents can capture dynamic variations of PD-L1 expression in entire tumors within and across multiple subjects. Towards this goal, several PD-L1 targeted molecular imaging probes have been evaluated in murine models and humans. However, clinical translation of these probes has been limited due to a significant non-specific accumulation of the imaging probes and the inability of conventional imaging modalities to provide quantitative readouts that can be compared across multiple subjects. Here we report that in vivo time-domain (TD) fluorescence imaging can provide quantitative estimates of baseline tumor PD-L1 heterogeneity across untreated mice and variations in PD-L1 expression across mice undergoing clinically relevant anti-PD1 treatment. This approach relies on a significantly longer fluorescence lifetime (FLT) of PD-L1 specific anti-PD-L1 antibody tagged to IRDye 800CW (αPDL1-800) compared to nonspecific αPDL1-800. Leveraging this unique FLT contrast, we show that PD-L1 expression can be quantified across mice both in superficial breast tumors using planar FLT imaging, and in deep-seated liver tumors (>5 mm depth) using the asymptotic TD algorithm for fluorescence tomography. Our results suggest that FLT contrast can accelerate the preclinical investigation and clinical translation of novel molecular imaging probes by providing robust quantitative readouts of receptor expression that can be readily compared across subjects.
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Affiliation(s)
- Rahul Pal
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Murali K
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Aya Matsui
- Department of Vascular Physiology, Graduate School of Medical Science, Kanazawa University, Japan
| | - Homan Kang
- Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Satoru Morita
- E. L. Steele Laboratories for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Hajime Taniguchi
- E. L. Steele Laboratories for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
- Department of Surgery, Tohoku Graduate School of Medicine, Sendai, Japan
| | - Tatsuya Kobayashi
- E. L. Steele Laboratories for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Atsuyo Morita
- E. L. Steele Laboratories for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Hak Soo Choi
- Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Dan G Duda
- E. L. Steele Laboratories for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Anand T N Kumar
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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2
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Abstract
The spatiotemporal determination of molecular events and cells is important for understanding disease processes, especially in oncology, and thus for the development of novel treatments. Equally important is the knowledge of the biodistribution, localization, and targeted accumulation of novel therapies as well as monitoring of tumor growth and therapeutic response. Optical imaging provides an ideal versatile platform for imaging of all these problems and questions.
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3
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Chib R, Requena S, Mummert M, Strzhemechny YM, Gryczynski I, Borejdo J, Gryczynski Z, Fudala R. Fluorescence lifetime imaging with time-gated detection of hyaluronidase using a long lifetime azadioxatriangulenium (ADOTA) fluorophore. Methods Appl Fluoresc 2016; 4:047001. [PMID: 28192308 DOI: 10.1088/2050-6120/4/4/047001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A fluorescence lifetime imaging probe with a long lifetime was used in combination with time-gating for the detection of hyaluronidase using hyaluronic acid as the probe template. This probe was developed by heavily labeling hyaluronic acid with long lifetime azadioxatriangulenium fluorophores (ADOTA). We used this probe to image hyaluronidase produced by DU-145 prostate cancer cells.
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Affiliation(s)
- Rahul Chib
- Institute of Molecular Medicine, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107, USA. Department of Food Science, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
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4
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Evaluation of a Flexible NOTA-RGD Kit Solution Using Gallium-68 from Different 68Ge/68Ga-Generators: Pharmacokinetics and Biodistribution in Nonhuman Primates and Demonstration of Solitary Pulmonary Nodule Imaging in Humans. Mol Imaging Biol 2016; 19:469-482. [DOI: 10.1007/s11307-016-1014-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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5
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Napp J, Pardo LA, Hartung F, Tietze LF, Stühmer W, Alves F. In vivo imaging of tumour xenografts with an antibody targeting the potassium channel K v10.1. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:721-733. [PMID: 27444284 PMCID: PMC5045485 DOI: 10.1007/s00249-016-1152-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/24/2016] [Accepted: 07/01/2016] [Indexed: 12/31/2022]
Abstract
The Kv10.1 (Eag1) voltage-gated potassium channel represents a promising molecular target for novel cancer therapies or diagnostic purposes. Physiologically, it is only expressed in the brain, but it was found overexpressed in more than 70 % of tumours of diverse origin. Furthermore, as a plasma membrane protein, it is easily accessible to extracellular interventions. In this study we analysed the feasibility of the anti-Kv10.1 monoclonal antibody mAb62 to target tumour cells in vitro and in vivo and to deliver therapeutics to the tumour. Using time-domain near infrared fluorescence (NIRF) imaging in a subcutaneous MDA-MB-435S tumour model in nude mice, we showed that mAb62-Cy5.5 specifically accumulates at the tumour for at least 1 week in vivo with a maximum intensity at 48 h. Blocking experiments with an excess of unlabelled mAb62 and application of the free Cy5.5 fluorophore demonstrate specific binding to the tumour. Ex vivo NIRF imaging of whole tumours as well as NIRF imaging and microscopy of tumour slices confirmed the accumulation of the mAb62-Cy5.5 in tumours but not in brain tissue. Moreover, mAb62 was conjugated to the prodrug-activating enzyme β-D-galactosidase (β-gal; mAb62-β-gal). The β-gal activity of the mAb62-β-gal conjugate was analysed in vitro on Kv10.1-expressing MDA-MB-435S cells in comparison to control AsPC-1 cells. We show that the mAb62-β-gal conjugate possesses high β-gal activity when bound to Kv10.1-expressing MDA-MB-435S cells. Moreover, using the β-gal activatable NIRF probe DDAOG, we detected mAb62-β-gal activity in vivo over the tumour area. In summary, we could show that the anti-Kv10.1 antibody is a promising tool for the development of novel concepts of targeted cancer therapy.
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Affiliation(s)
- Joanna Napp
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany.,Institute of Interventional and Diagnostic Radiology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.,Department of Haematology and Medical Oncology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Luis A Pardo
- AG Oncophysiology, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Franziska Hartung
- AG Oncophysiology, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Lutz F Tietze
- Institute of Organic and Biomolecular Chemistry, University Göttingen, Tammannstr. 2, 37077, Göttingen, Germany
| | - Walter Stühmer
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Frauke Alves
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany. .,Institute of Interventional and Diagnostic Radiology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany. .,Department of Haematology and Medical Oncology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
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6
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Yan X, Wu G, Qu Q, Fan X, Xu X, Liu N. A Hybrid Peptide PTS that Facilitates Transmembrane Delivery and Its Application for the Rapid In vivo Imaging via Near-Infrared Fluorescence Imaging. Front Pharmacol 2016; 7:51. [PMID: 27014065 PMCID: PMC4782124 DOI: 10.3389/fphar.2016.00051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 02/23/2016] [Indexed: 01/27/2023] Open
Abstract
Background and purpose: Intravital imaging provides invaluable readouts for clinical diagnoses and therapies and shows great potential in the design of individualized drug dosage regimes. Ts is a mammalian free cell membrane-penetrating peptide. This study aimed to introduce a novel approach to the design of a cancer-selective peptide on the basis of a membrane-penetrating peptide and to explore its potential as a carrier of medical substances. Experimental approach:Ts was linked with a αvβ3-binding peptide P1c to create a hybrid referred to as PTS. The hybrid was labeled with an FITC or Cy5.5 as an imaging indicator to evaluate its in vitro and in vivo bioactivity. Key results:Hemolysis tests proved that in comparison with Ts, PTS caused similar or even less leakage of human erythrocytes at concentrations of up to 1 mmol/L. Flow cytometry assay and confocal microscopy demonstrated the following. (1) P1c alone could target and mostly halt at the cancer cell membrane. (2) Ts alone could not bind to the membrane sufficiently. (3) P1c greatly enhanced the binding affinity of PTS with MDA-MB-231 breast cancer cells that upregulated αvβ3. (4) Ts conferred PTS with the ability to traverse a cell membrane and thus facilitate the transmembrane delivery of imaging probes. In vivo near-infrared fluorescence (NIRF) imaging demonstrated that the imaging probes were rapidly concentrated in a MDA-MB-231 tumor tissue within 1 h after intravenous injection. Conclusions and implications:PTS exhibited the capability of targeting specific tumors and greatly facilitating the transmembrane delivery of imaging probes.
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Affiliation(s)
- Xuejiao Yan
- Department of Cardiology, Affiliated Zhongda Hospital, Medical School of Southeast University Nanjing, China
| | - Guoqiu Wu
- Center of Clinical Laboratory Medicine of Zhongda Hospital, Institute of Biotechnology and Clinical Pharmacy, Medical School of Southeast University Nanjing, China
| | - Qingrong Qu
- Department of Cardiology, Affiliated Zhongda Hospital, Medical School of Southeast University Nanjing, China
| | - Xiaobo Fan
- Center of Clinical Laboratory Medicine of Zhongda Hospital, Institute of Biotechnology and Clinical Pharmacy, Medical School of Southeast University Nanjing, China
| | - Xudong Xu
- Department of Biological Engineering, Medical School of Southeast University Nanjing, China
| | - Naifeng Liu
- Department of Cardiology, Affiliated Zhongda Hospital, Medical School of Southeast University Nanjing, China
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7
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Development of a high-throughput screening-compatible assay to identify inhibitors of the CK2α/CK2β interaction. Anal Biochem 2015; 468:4-14. [DOI: 10.1016/j.ab.2014.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/22/2014] [Accepted: 09/05/2014] [Indexed: 01/10/2023]
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8
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Alsibai W, Hahnenkamp A, Eisenblätter M, Riemann B, Schäfers M, Bremer C, Haufe G, Höltke C. Fluorescent Non-peptidic RGD Mimetics with High Selectivity for αVβ3 vs αIIbβ3 Integrin Receptor: Novel Probes for in Vivo Optical Imaging. J Med Chem 2014; 57:9971-82. [DOI: 10.1021/jm501197c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
| | | | - Michel Eisenblätter
- Division
of Imaging Sciences, King’s College London, London SE1 7EH, United Kingdom
| | | | | | - Christoph Bremer
- Clinic for Radiology, St. Franziskus Hospital Muenster, Muenster D-48145, Germany
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9
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Advances in imaging probes and optical microendoscopic imaging techniques for early in vivo cancer assessment. Adv Drug Deliv Rev 2014; 74:53-74. [PMID: 24120351 DOI: 10.1016/j.addr.2013.09.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 09/18/2013] [Accepted: 09/27/2013] [Indexed: 12/12/2022]
Abstract
A new chapter in the history of medical diagnosis happened when the first X-ray technology was invented in the late 1800s. Since then, many non-invasive and minimally invasive imaging techniques have been invented for clinical diagnosis to research in cellular biology, drug discovery, and disease monitoring. These imaging modalities have leveraged the benefits of significant advances in computer, electronics, and information technology and, more recently, targeted molecular imaging. The development of targeted contrast agents such as fluorescent and nanoparticle probes coupled with optical imaging techniques has made it possible to selectively view specific biological events and processes in both in vivo and ex vivo systems with great sensitivity and selectivity. Thus, the combination of targeted molecular imaging probes and optical imaging techniques have become a mainstay in modern medicinal and biological research. Many promising results have demonstrated great potentials to translate to clinical applications. In this review, we describe a discussion of employing imaging probes and optical microendoscopic imaging techniques for cancer diagnosis.
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10
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Hoffmann K, Behnke T, Drescher D, Kneipp J, Resch-Genger U. Near-infrared-emitting nanoparticles for lifetime-based multiplexed analysis and imaging of living cells. ACS NANO 2013; 7:6674-6684. [PMID: 23837453 DOI: 10.1021/nn4029458] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The increase in information content from bioassays and bioimaging requires robust and efficient strategies for the detection of multiple analytes or targets in a single measurement, thereby addressing current health and security concerns. For fluorescence techniques, an attractive alternative to commonly performed spectral or color multiplexing presents lifetime multiplexing and the discrimination between different fluorophores based on their fluorescence decay kinetics. This strategy relies on fluorescent labels with sufficiently different lifetimes that are excitable at the same wavelength and detectable within the same spectral window. Here, we report on lifetime multiplexing and discrimination with a set of nanometer-sized particles loaded with near-infrared emissive organic fluorophores chosen to display very similar absorption and emission spectra, yet different fluorescence decay kinetics in suspension. Furthermore, as a first proof-of-concept, we describe bioimaging studies with 3T3 fibroblasts and J774 macrophages, incubated with mixtures of these reporters employing fluorescence lifetime imaging microscopy. These proof-of-concept measurements underline the potential of fluorescent nanoparticle reporters in fluorescence lifetime multiplexing, barcoding, and imaging for cellular studies, cell-based assays, and molecular imaging.
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Affiliation(s)
- Katrin Hoffmann
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Straße 11, 12489 Berlin, Germany
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11
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Pauli J, Licha K, Berkemeyer J, Grabolle M, Spieles M, Wegner N, Welker P, Resch-Genger U. New Fluorescent Labels with Tunable Hydrophilicity for the Rational Design of Bright Optical Probes for Molecular Imaging. Bioconjug Chem 2013; 24:1174-85. [PMID: 23758616 DOI: 10.1021/bc4000349] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jutta Pauli
- BAM Federal Institute for Materials Research and Testing, Division 1.10 Biophotonics,
Richard-Willstaetter-Strasse 11, D-12489 Berlin, Germany
| | - Kai Licha
- mivenion GmbH, Robert-Koch-Platz 4, D-10115 Berlin, Germany
| | - Janis Berkemeyer
- BAM Federal Institute for Materials Research and Testing, Division 1.10 Biophotonics,
Richard-Willstaetter-Strasse 11, D-12489 Berlin, Germany
| | - Markus Grabolle
- BAM Federal Institute for Materials Research and Testing, Division 1.10 Biophotonics,
Richard-Willstaetter-Strasse 11, D-12489 Berlin, Germany
| | - Monika Spieles
- BAM Federal Institute for Materials Research and Testing, Division 1.10 Biophotonics,
Richard-Willstaetter-Strasse 11, D-12489 Berlin, Germany
| | - Nicole Wegner
- mivenion GmbH, Robert-Koch-Platz 4, D-10115 Berlin, Germany
| | - Pia Welker
- mivenion GmbH, Robert-Koch-Platz 4, D-10115 Berlin, Germany
| | - Ute Resch-Genger
- BAM Federal Institute for Materials Research and Testing, Division 1.10 Biophotonics,
Richard-Willstaetter-Strasse 11, D-12489 Berlin, Germany
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12
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Elimination of autofluorescence background from fluorescence tissue images by use of time-gated detection and the AzaDiOxaTriAngulenium (ADOTA) fluorophore. Anal Bioanal Chem 2012; 405:2065-75. [PMID: 23254457 DOI: 10.1007/s00216-012-6623-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 11/27/2012] [Accepted: 11/29/2012] [Indexed: 10/27/2022]
Abstract
Sample autofluorescence (fluorescence of inherent components of tissue and fixative-induced fluorescence) is a significant problem in direct imaging of molecular processes in biological samples. A large variety of naturally occurring fluorescent components in tissue results in broad emission that overlaps the emission of typical fluorescent dyes used for tissue labeling. In addition, autofluorescence is characterized by complex fluorescence intensity decay composed of multiple components whose lifetimes range from sub-nanoseconds to a few nanoseconds. For these reasons, the real fluorescence signal of the probe is difficult to separate from the unwanted autofluorescence. Here we present a method for reducing the autofluorescence problem by utilizing an azadioxatriangulenium (ADOTA) dye with a fluorescence lifetime of approximately 15 ns, much longer than those of most of the components of autofluorescence. A probe with such a long lifetime enables us to use time-gated intensity imaging to separate the signal of the targeting dye from the autofluorescence. We have shown experimentally that by discarding photons detected within the first 20 ns of the excitation pulse, the signal-to-background ratio is improved fivefold. This time-gating eliminates over 96 % of autofluorescence. Analysis using a variable time-gate may enable quantitative determination of the bound probe without the contributions from the background.
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13
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Behnke T, Mathejczyk JE, Brehm R, Würth C, Gomes FR, Dullin C, Napp J, Alves F, Resch-Genger U. Target-specific nanoparticles containing a broad band emissive NIR dye for the sensitive detection and characterization of tumor development. Biomaterials 2012; 34:160-70. [PMID: 23072943 DOI: 10.1016/j.biomaterials.2012.09.028] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 09/15/2012] [Indexed: 02/08/2023]
Abstract
Current optical probes including engineered nanoparticles (NPs) are constructed from near infrared (NIR)-emissive organic dyes with narrow absorption and emission bands and small Stokes shifts prone to aggregation-induced self-quenching. Here, we present the new asymmetric cyanine Itrybe with broad, almost environment-insensitive absorption and emission bands in the diagnostic window, offering a unique flexibility of the choice of excitation and detection wavelengths compared to common NIR dyes. This strongly emissive dye was spectroscopically studied in different solvents and encapsulated into differently sized (15, 25, 100 nm) amino-modified polystyrene NPs (PSNPs) via a one-step staining procedure. As proof-of-concept for its potential for pre-/clinical imaging applications, Itrybe-loaded NPs were surface-functionalized with polyethylene glycol (PEG) and the tumor-targeting antibody Herceptin and their binding specificity to the tumor-specific biomarker HER2 was systematically assessed. Itrybe-loaded NPs display strong fluorescence signals in vitro and in vivo and Herceptin-conjugated NPs bind specifically to HER2 as demonstrated in immunoassays as well as on tumor cells and sections from mouse tumor xenografts in vitro. This demonstrates that our design strategy exploiting broad band-absorbing and -emitting dyes yields versatile and bright NIR probes with a high potential for e.g. the sensitive detection and characterization of tumor development and progression.
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Affiliation(s)
- Thomas Behnke
- BAM Federal Institute for Materials Research and Testing, 1.10, Richard-Willstätter-Str. 11, 12489 Berlin, Germany
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14
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Mathejczyk JE, Pauli J, Dullin C, Resch-Genger U, Alves F, Napp J. High-sensitivity detection of breast tumors in vivo by use of a pH-sensitive near-infrared fluorescence probe. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:076028. [PMID: 22894511 DOI: 10.1117/1.jbo.17.7.076028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We investigated the potential of the pH-sensitive dye, CypHer5E, conjugated to Herceptin (pH-Her) for the sensitive detection of breast tumors in mice using noninvasive time-domain near-infrared fluorescence imaging and different methods of data analysis. First, the fluorescence properties of pH-Her were analyzed as function of pH and/or dye-to-protein ratio, and binding specificity was confirmed in cell-based assays. Subsequently, the performance of pH-Her in nude mice bearing orthotopic HER2-positive (KPL-4) and HER2-negative (MDA-MB-231) breast carcinoma xenografts was compared to that of an always-on fluorescent conjugate Alexa Fluor 647-Herceptin (Alexa-Her). Subtraction of autofluorescence and lifetime (LT)-gated image analyses were performed for background fluorescence suppression. In mice bearing HER2-positive tumors, autofluorescence subtraction together with the selective fluorescence enhancement of pH-Her solely in the tumor's acidic environment provided high contrast-to-noise ratios (CNRs). This led to an improved sensitivity of tumor detection compared to Alexa-Her. In contrast, LT-gated imaging using LTs determined in model systems did not improve tumor-detection sensitivity in vivo for either probe. In conclusion, pH-Her is suitable for sensitive in vivo monitoring of HER2-expressing breast tumors with imaging in the intensity domain and represents a promising tool for detection of weak fluorescent signals deriving from small tumors or metastases.
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Affiliation(s)
- Julia Eva Mathejczyk
- Max-Planck-Institute for Experimental Medicine, Department of Molecular Biology of Neuronal Signals, 37075 Göttingen, Germany
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15
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Würth C, Pauli J, Lochmann C, Spieles M, Resch-Genger U. Integrating Sphere Setup for the Traceable Measurement of Absolute Photoluminescence Quantum Yields in the Near Infrared. Anal Chem 2012; 84:1345-52. [DOI: 10.1021/ac2021954] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Christian Würth
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Strasse 11, 12489
Berlin, Germany
| | - Jutta Pauli
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Strasse 11, 12489
Berlin, Germany
| | - Cornelia Lochmann
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Strasse 11, 12489
Berlin, Germany
| | - Monika Spieles
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Strasse 11, 12489
Berlin, Germany
| | - Ute Resch-Genger
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Strasse 11, 12489
Berlin, Germany
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