Publications by authors named "Kazuhide Sato"

61 Publications

Near Infrared Photoimmunotherapy for Mouse Models of Pleural Dissemination.

J Vis Exp 2021 02 9(168). Epub 2021 Feb 9.

Respiratory Medicine, Nagoya University Graduate School of Medicine; Nagoya University Institute for Advanced Research; B3-Unit, Advanced Analytical and Diagnostic Imaging Center (AADIC)/Medical Engineering Unit (MEU), Nagoya University Institute for Advanced Research;

The efficacy of photoimmunotherapy can be evaluated more accurately with an orthotopic mouse model than with a subcutaneous one. A pleural dissemination model can be used for the evaluation of treatment methods for intrathoracic diseases such as lung cancer or malignant pleural mesothelioma. Near-infrared photoimmunotherapy (NIR-PIT) is a recently developed cancer treatment strategy that combines the specificity of tumor-targeting antibodies with toxicity caused by a photoabsorber (IR700Dye) after exposure to NIR light. The efficacy of NIR-PIT has been reported using various antibodies; however, only a few reports have shown the therapeutic effect of this strategy in an orthotopic model. In the present study, we demonstrate an example of efficacy evaluation of the pleural disseminated lung cancer model, which was treated using NIR-PIT.
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http://dx.doi.org/10.3791/61593DOI Listing
February 2021

Tough and Three-Dimensional-Printable Poly(2-methoxyethyl acrylate)-Silica Composite Elastomer with Antiplatelet Adhesion Property.

ACS Appl Mater Interfaces 2020 Oct 1;12(41):46621-46628. Epub 2020 Oct 1.

Department of Molecular & Macromolecular Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.

Poly(2-methoxyethyl acrylate) (PMEA) has attracted attention as a biocompatible polymer that is used as an antithrombotic coating agent for medical devices, such as during artificial heart and lung fabrication. However, PMEA is a viscous liquid polymer with low , and its physical strength is poor even if a cross-linker is used, so it is difficult to make tough and freestanding objects from it. Here, we design and fabricate a biocompatible elastomer made of tough, self-supporting PMEA-silica composites. The toughness of the composite elastomer increases as a function of silica particle filling, and its stress at break is improved from 0.3 to 6.7 MPa. The fracture energy of the composite elastomer with 39.5 vol % silica particles is up to 15 times higher than that of the cross-linked PMEA with no silica particles and the material demonstrates stress-strain behavior that is similar to that of biological soft tissue, which exhibits nonlinear elasticity. In addition, the composite elastomer shows the potential to be an antithrombotic property, while the results of the platelet adhesion test of the composite elastomer show that the number of adhered platelets is not significantly affected by the silica addition. As the composite elastomer can be rapidly three-dimensional-printed into complex geometries with high-resolution features, it is expected to contribute to the development of medical devices from readily available materials.
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http://dx.doi.org/10.1021/acsami.0c11416DOI Listing
October 2020

The "light" guide for surgery.

Authors:
Kazuhide Sato

EBioMedicine 2020 Jun 5;56:102808. Epub 2020 Jun 5.

Nagoya University Institute for Advanced Research, S-YLC, Japan; Respiratory Medicine, Nagoya University Graduate School of Medicine, Japan; Nagoya University Institute for Advanced Research, B3-Unit, Advanced Analytical and Diagnostic Imaging Center (AADIC) / Medical Engineering Unit (MEU), Japan. Electronic address:

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http://dx.doi.org/10.1016/j.ebiom.2020.102808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7276511PMC
June 2020

Targeted Phototherapy for Malignant Pleural Mesothelioma: Near-Infrared Photoimmunotherapy Targeting Podoplanin.

Cells 2020 04 20;9(4). Epub 2020 Apr 20.

National Hospital Organization, Nagoya Medical Center, Nagoya 460-0001, Japan.

Malignant pleural mesothelioma (MPM) has extremely limited treatment despite a poor prognosis. Moreover, molecular targeted therapy for MPM has not yet been implemented; thus, a new targeted therapy is highly desirable. Near-infrared photoimmunotherapy (NIR-PIT) is a recently developed cancer therapy that combines the specificity of antibodies for targeting tumors with toxicity induced by the photoabsorber after exposure to NIR-light. In this study, we developed a new phototherapy targeting podoplanin (PDPN) for MPM with the use of both NIR-PIT and an anti-PDPN antibody, NZ-1. An antibody-photosensitizer conjugate consisting of NZ-1 and phthalocyanine dye was synthesized. In vitro NIR-PIT-induced cytotoxicity was measured with both dead cell staining and luciferase activity on various MPM cell lines. In vivo NIR-PIT was examined in both the flank tumor and orthotopic mouse model with in vivo real-time imaging. In vitro NIR-PIT-induced cytotoxicity was NIR-light dose dependent. In vivo NIR-PIT led to significant reduction in both tumor volume and luciferase activity in a flank model ( < 0.05, NIR-PIT group versus NZ-1-IR700 group). The PDPN-targeted NIR-PIT resulted in a significant antitumor effect in an MPM orthotopic mouse model ( < 0.05, NIR-PIT group versus NZ-1-IR700 group). This study suggests that PDPN-targeted NIR-PIT could be a new promising treatment for MPM.
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http://dx.doi.org/10.3390/cells9041019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225918PMC
April 2020

Near infrared photoimmunotherapy targeting DLL3 for small cell lung cancer.

EBioMedicine 2020 Feb 23;52:102632. Epub 2020 Jan 23.

National Hospital Organization, Nagoya Medical Center, Japan.

Background: Small cell lung cancer (SCLC) has a poor prognosis, and its treatment options are limited. Delta-like protein 3 (DLL3) is expressed specifically in SCLC and is considered a promising therapeutic target for patients with this disease. Rovalpituzumab tesirine (Rova-T) was the first antibody-drug conjugate targeting DLL3. Although Rova-T development was unfortunately terminated, DLL3 remains an ideal target for SCLC. Near infrared photoimmunotherapy (NIR-PIT) is a new form of cancer treatment that employs an antibody-photosensitiser conjugate followed by NIR light exposure and damage target cells specifically. In this study, we demonstrate DLL3-targeted NIR-PIT to develop a novel molecularly targeted treatment for SCLC.

Methods: The anti-DLL3 monoclonal antibody rovalpituzumab was conjugated to an IR700 photosensitiser (termed 'rova-IR700'). SCLC cells overexpressing DLL3 as well as non-DLL3-expressing controls were incubated with rova-IR700 and then exposed to NIR-light. Next, mice with SCLC xenografts were injected with rova-IR700 and irradiated with NIR-light.

Findings: DLL3-overexpressing cells underwent immediate destruction upon NIR-light exposure, whereas the control cells remained intact. The xenograft in mice treated with rova-IR700 and NIR-light shrank markedly, whereas neither rova-IR700 injection nor NIR-light irradiation alone affected tumour size.

Interpretation: Our data suggest that targeting of DLL3 using NIR-PIT could be a novel and promising treatment for SCLC.

Funding: Research supported by grants from the Program for Developing Next-generation Researchers (Japan Science and Technology Agency), KAKEN (18K15923, JSPS), Medical Research Encouragement Prize of The Japan Medical Association, The Nitto Foundation, Kanae Foundation for the Promotion of Medical Science.
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http://dx.doi.org/10.1016/j.ebiom.2020.102632DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6992936PMC
February 2020

Photoinduced Ligand Release from a Silicon Phthalocyanine Dye Conjugated with Monoclonal Antibodies: A Mechanism of Cancer Cell Cytotoxicity after Near-Infrared Photoimmunotherapy.

ACS Cent Sci 2018 Nov 6;4(11):1559-1569. Epub 2018 Nov 6.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1088, United States.

Photochemical reactions can dramatically alter physical characteristics of reacted molecules. In this study, we demonstrate that near-infrared (NIR) light induces an axial ligand-releasing reaction, which dramatically alters hydrophilicity of a silicon phthalocyanine derivative (IR700) dye leading to a change in the shape of the conjugate and its propensity to aggregate in aqueous solution. This photochemical reaction is proposed as a major mechanism of cell death induced by NIR photoimmunotherapy (NIR-PIT), which was recently developed as a molecularly targeted cancer therapy. Once the antibody-IR700 conjugate is bound to its target, activation by NIR light causes physical changes in the shape of antibody antigen complexes that are thought to induce physical stress within the cellular membrane leading to increases in transmembrane water flow that eventually lead to cell bursting and necrotic cell death.
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http://dx.doi.org/10.1021/acscentsci.8b00565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6276043PMC
November 2018

Implantable wireless powered light emitting diode (LED) for near-infrared photoimmunotherapy: device development and experimental assessment and .

Oncotarget 2018 Apr 13;9(28):20048-20057. Epub 2018 Apr 13.

Laboratory of Bioanalysis and Molecular Imaging, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan.

Purpose: The aim of this study was to develop and assess a novel implantable, wireless-powered, light-emitting diode (LED) for near-infrared photoimmunotherapy (NIR-PIT). NIR-PIT is a recently developed cancer therapy that uses NIR light and antibody-photosensitizer conjugates and is able to induce cancer-specific cell death. Due to limited light penetration depth it is currently unable to treat tumors in deep tissues. Use of implanted LED might potentially overcome this limitation.

Results: The wireless LED system was able to emit NIR light up to a distance of 20 cm from the transmitter coil by using low magnetic fields as compliant with limits for use in humans. Results indicated that the LED system was able to kill tumor cells and to suppress tumor growth in implanted tumor-bearing mice.

Conclusions: Results indicated that the proposed implantable wireless LED system was able to suppress tumor growth . These results are encouraging as wireless LED systems such as the one here developed might be a possible solution to treat tumors in deep regions in humans. Further research in this area would be important.

Materials And Methods: An implantable LED system was developed. It consisted of a LED capsule including two LED sources and a receiver coil coupled with an external coil and power source. Wireless power transmission was guaranteed by using electromagnetic induction. The system was tested by using EGFR-expressing cells and HER2-expressing cells. The system was also tested in tumor-bearing mice.
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http://dx.doi.org/10.18632/oncotarget.25068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5929445PMC
April 2018

3D mesoscopic fluorescence tomography for imaging micro-distribution of antibody-photon absorber conjugates during near infrared photoimmunotherapy in vivo.

J Control Release 2018 06 16;279:171-180. Epub 2018 Apr 16.

University of Maryland, Fischell Department of Bioengineering, 2218 Jeong H.Kim Engineering Building, College Park, MD 20742, United States. Electronic address:

As a novel low-side-effect cancer therapy, photo-immunotherapy (PIT) is based on conjugating monoclonal antibody (mAb) with a near-infrared (NIR) phthalocyanine dye IRDye700DX (IR 700). IR700 is not only fluorescent to be used as an imaging agent, but also phototoxic. When illuminating with NIR light, PIT can induce highly-selective cancer cell death while leaving most of tumor blood vessels unharmed, leading to an effect termed super-enhanced permeability and retention (SUPR), which can significantly improve the effectiveness of anti-cancer drug. Currently, the therapeutic effects of PIT are monitored using 2D macroscopic fluorescence reflectance imager, which lacks the resolution and depth information to reveal the 3D distribution of mAb-IR700. In the study, we applied a multi-modal optical imaging approach including high-resolution optical coherence tomography (OCT) and high-sensitivity fluorescence laminar optical tomography (FLOT), to provide 3D tumor micro-structure and micro-distribution of mAb-IR700 in the tumor simultaneously during PIT in situ and in vivo. The multi-wavelength FLOT can also provide the blood vessels morphology of the tumor. Thus, the 3D FLOT reconstructed images allow us to evaluate the IR700 fluorescence distribution change with respect to the blood vessels and at different tumor locations/depths non-invasively, thereby enabling evaluation of the therapeutic effects in vivo and optimization of treatment regimens accordingly. The mAb-IR700 can access more tumor areas after PIT treatment, which can be explained by increased vascular permeability immediately after NIR-PIT. Two-photon microscopy was also used to record the mAb-IR700 on the tumor surface near the blood vessels to verify the results.
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http://dx.doi.org/10.1016/j.jconrel.2018.04.027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5972681PMC
June 2018

Interstitial near-infrared photoimmunotherapy: effective treatment areas and light doses needed for use with fiber optic diffusers.

Oncotarget 2018 Feb 27;9(13):11159-11169. Epub 2018 Jan 27.

National Institutes of Health, National Cancer Institute, Molecular Imaging Program, Bethesda, Maryland 20892-1088, United States.

Near-infrared photoimmunotherapy (NIR-PIT), a promising cancer therapy utilizing an antibody-photoabsorber conjugate (APC) and NIR light, which induces rapid necrotic cell death only in APC-bound cells. Effective NIR-PIT in mouse models has been achieved using superficial light illumination (SLI) with light emitting diodes (LEDs) or lasers, but in the clinical setting, fiber optic diffusers have been employed to deliver light to deeper tumors. However, the performance of NIR light in tissue delivered by fiber optic diffusers is poorly understood. Here, we investigated NIR-PIT using a cylindrical fiber optic diffuser in a mouse model of A431 tumors. NIR-PIT with 100 J/cm, the same light dose used in clinical trials of NIR-PIT, was applied after insertion of the diffuser within the tumor bed, and then both bioluminescence and fluorescence imaging were analyzed to assess the therapeutic efficacy. The diffuser can deliver adequate NIR light dose for effective NIR-PIT to the A431 tumor at a distance of approximately 1 cm around the light source at 100 J/cm. At 50 J/cm NIR light effective NIR-PIT was reduced to a distance of 5 - 7 mm diameter around the light source. These results indicate that the energy of interstitial light (measured in Joules/cm) administered via a fiber diffuser determines the depth of effective NIR-PIT around the diffuser and determines the spacing at which such diffusers should be placed to entirely cover the tumor. Thermal measurements demonstrate that interstitial light for NIR-PIT does not cause damage to the skin overlying the diffuser.
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http://dx.doi.org/10.18632/oncotarget.24329DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5834257PMC
February 2018

Near Infrared Photoimmunotherapy with Combined Exposure of External and Interstitial Light Sources.

Mol Pharm 2018 09 21;15(9):3634-3641. Epub 2018 Feb 21.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States.

Near infrared photoimmunotherapy (NIR-PIT) is a new target-cell-specific cancer treatment that induces highly selective necrotic/immunogenic cell death after systemic administration of a photoabsorber antibody conjugate and subsequent NIR light exposure. However, the depth of NIR light penetration in tissue (approximately 2 cm) with external light sources limits the therapeutic effects of NIR-PIT. Interstitial light exposure using cylindrical diffusing optical fibers can overcome this limitation. The purpose in this study was to compare three NIR light delivery methods for treating tumors with NIR-PIT using a NIR laser system at an identical light energy; external exposure alone, interstitial exposure alone, and the combination. Panitumumab conjugated with the photoabsorber IRDye-700DX (pan-IR700) was intravenously administered to mice with A431-luc xenografts which are epithelial growth factor receptor (EGFR) positive. One and 2 days later, NIR light was administered to the tumors using one of three methods. Interstitial exposure alone and in combination with external sources showed the greatest decrease in bioluminescence signal intensity. Additionally, the combination of external and interstitial NIR light exposure showed significantly greater tumor size reduction and prolonged survival after NIR-PIT compared to external exposure alone. This result suggested that the combination of external and interstitial NIR light exposure was more effective than externally applied light alone. Although external exposure is the least invasive means of delivering light, the combination of external and interstitial exposures produces superior therapeutic efficacy in tumors greater than 2 cm in depth from the tissue surface.
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http://dx.doi.org/10.1021/acs.molpharmaceut.8b00002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7400989PMC
September 2018

Avoiding thermal injury during near-infrared photoimmunotherapy (NIR-PIT): the importance of NIR light power density.

Oncotarget 2017 Dec 11;8(68):113194-113201. Epub 2017 Aug 11.

National Institutes of Health, National Cancer Institute, Molecular Imaging Program, Bethesda, Maryland, 20892, United States.

Near-infrared photoimmunotherapy (NIR-PIT) is a newly-established cancer treatment which employs the combination of an antibody-photoabsorber conjugate (APC) and NIR light. When NIR light is absorbed by APC-bound tissues, a certain amount of heat is generated locally. For the most part this results in a subclinical rise in skin temperature, however, excessive light exposure may cause non-specific thermal damage. In this study, we investigated the potential for thermal damage caused by NIR-PIT by measuring surface temperature. Two sources of light, laser and light emitting diode (LED), were compared in a mouse tumor model. First, we found that the skin was heated rapidly by NIR light regardless of whether laser or LED light sources were used. Air cooling at the surface reduced the rise in temperature. There were no associations between the rise of skin temperature and tumor volume of the treated tumor, or APC concentration. Second, we investigated the extent of thermal damage to the skin at various light doses. We detected burn injuries 1 day after NIR-PIT, when the NIR light was at a power density higher than 600 mW/cm. Successful treatments at lower power density could be achieved if the total light energy absorbed by the tumor was the same, i.e. by extending the duration of light exposure. In conclusion, this study demonstrates that thermal injury after NIR-PIT can be avoided by either employing a cooling system or by lowering the power density of the light source and prolonging the exposure time such that the total energy is constant. Thus, thermal damage is preventable side effect of NIR-PIT.
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http://dx.doi.org/10.18632/oncotarget.20179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5762583PMC
December 2017

Evaluation of Early Therapeutic Effects after Near-Infrared Photoimmunotherapy (NIR-PIT) Using Luciferase-Luciferin Photon-Counting and Fluorescence Imaging.

Mol Pharm 2017 12 22;14(12):4628-4635. Epub 2017 Nov 22.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH , Bethesda, Maryland 20892, United States.

Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that induces highly selective immunogenic cell death. It is based on an antibody-photoabsorber conjugate (APC) that is activated by NIR light. The purpose of this study was to investigate the effects of NIR-PIT as measured by luciferase-luciferin photon-counting and fluorescence imaging. Six days after subcutaneous injection of A431-luc-GFP cells tumors formed in a xenograft mouse model. The EGFR-targeting antibody, panitumumab, was conjugated to the photoabsorber, IRDye-700DX (pan-IR700), and was intravenously administered to tumor-bearing mice. Serial luciferase-luciferin photon-counting images and both green fluorescent protein (GFP) and IR700 fluorescence images were obtained from the same mice before and after NIR-PIT treatment (0, 10, 20, 30 min (early phase), and 24, 48 h (late phase) after NIR light exposure). Optical signal intensities were compared for each modality. IR700 fluorescence and luciferase-luciferin photon-counting images showed decreased intensities in both the early and late phases after NIR-PIT (p < 0.01). On the other hand, GFP fluorescence images showed decreased intensities only in the late phase (p < 0.01). In the early phase, GFP fluorescence images showed smaller intensity reductions compared to IR700 fluorescence and luciferase-luciferin photon-counting (p < 0.01), while in the late phase, IR700 fluorescence showed smaller intensity reductions than luciferase-luciferin photon-counting and GFP fluorescence (p < 0.05), due to redistribution of pan-IR700 within the tumor bed. In conclusion, luciferase-luciferin photon-counting imaging is suitable to evaluate early phase NIR-PIT effects, while both luciferase-luciferin photon-counting and GFP reflected later phase effects.
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http://dx.doi.org/10.1021/acs.molpharmaceut.7b00731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6333314PMC
December 2017

Characteristics of ovarian cancer detection by a near-infrared fluorescent probe activated by human NAD(P)H: quinone oxidoreductase isozyme 1 (hNQO1).

Oncotarget 2017 Sep 20;8(37):61181-61192. Epub 2017 May 20.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, United States National Institutes of Health, Bethesda, Maryland 20892-1088, USA.

Near-infrared (NIR) fluorescent probes are ideal for imaging, because they offer deeper tissue penetration by the light and lower background autofluorescence than fluorophores that emit in the visible range. QSTCy is a newly synthesized, NIR light-emitting probe that is activated by an enzyme commonly overexpressed in tumor cells, human nicotinamide adenine dinucleotide (phosphate): quinone oxidoreductase isozyme 1, known as hNQO1 or DT-diaphorase. The purpose of this study is to compare the sensitivity of detecting peritoneal ovarian cancer metastasis (POCM) with QSTCy and gGlu-HMRG, a green fluorescent probe, upon their surface application. uptake of QSTCy was significantly higher than that of gGlu-HMRG. Using a red fluorescence protein (RFP)-labeled tumor model of POCM, the QSTCy probe provided high sensitivity (96.9%) but modest specificity (61.0%), most likely the result of albumin-probe interactions and non-specific activation in nearby altered but healthy cells. Three types of kinetic maps based on maximum fluorescence signal (MF), wash-in rate (WIR), and area under the curve (AUC) allowed for differentiation of the activated fluorescence signal associated with POCM from the background signal of the small intestine, thereby significantly improving the specificity of QSTCy to 80%, 100%, and 100% for MF, WIR, and AUC, as well yielding a moderate improvement in sensitivity (100% for all approaches) that is comparable to that with gGlu-HMRG, but with the added advantages of NIR fluorescence as the transduction modality. Such a new methodology has the potential to afford identification of cancerous lesions deeper within tissue.
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http://dx.doi.org/10.18632/oncotarget.18044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5617415PMC
September 2017

Real-time monitoring of microdistribution of antibody-photon absorber conjugates during photoimmunotherapy in vivo.

J Control Release 2017 08 8;260:154-163. Epub 2017 Jun 8.

University of Maryland, Fischell Department of Bioengineering, 2218 Jeong H.Kim Engineering Building, College Park, MD 20742, United States. Electronic address:

Photoimmunotherapy (PIT) is an emerging low side effect cancer therapy based on a monoclonal antibody (mAb) conjugated with a near-infrared (NIR) phthalocyanine dye IRDye 700DX. IR700 is fluorescent, can be used as an imaging agent, and also is phototoxic. It induces rapid cell death after exposure to NIR light. PIT induces highly selective cancer cell death, while leaving most of tumor blood vessels unharmed, leading to an effect called super-enhanced permeability and retention (SUPR). SUPR significantly improves the effectiveness of the anticancer drug. Currently, the therapeutic effects of PIT are monitored using the IR700 fluorescent signal based on macroscopic fluorescence reflectance imagery. This technique, however, lacks the resolution and depth information to reveal the intratumor heterogeneity of mAb-IR700 distribution. We applied a minimally invasive two-channel fluorescence fiber imaging system by combining the traditional fluorescence imaging microscope with two imaging fiber bundles (~0.85mm). This method monitored mAb-IR700 distribution and therapeutic effects during PIT at different intratumor locations (e.g., tumor surface vs. deep tumor) in situ and in real time simultaneously. This enabled evaluation of the therapeutic effects in vivo and treatment regimens. The average IR700 fluorescence intensity recovery after PIT to the tumor surface is 91.50%, while it is 100.63% in deep tumors. To verify the results, two-photon microscopy combined with a microprism was also used to record the mAb-IR700 distribution and fluorescence intensity of green fluorescent protein (GFP) at different tumor depths during PIT. After PIT treatment, there was significantly higher IR700 fluorescence recovery in deep tumor than in the tumor surface. This phenomenon can be explained by increased vascular permeability immediately after NIR-PIT. Fluorescence intensity of GFP at the tumor surface decreased significantly more compared to that of deep tumor and in controls (no PIT).
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http://dx.doi.org/10.1016/j.jconrel.2017.06.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5726775PMC
August 2017

Near-infrared photoimmunotherapy: a comparison of light dosing schedules.

Oncotarget 2017 May;8(21):35069-35075

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, 20892, United States of America.

Near infrared photoimmunotherapy (NIR-PIT) is a newly-developed cancer therapy in which a monoclonal antibody is conjugated to a near-infrared photoabsorber, IR700 to form an antibody photoabsorber conjugate (APC). After the APC binds to cancer cells expressing the cognate antigen, exposure to NIR light results in rapid, highly selective necrotic cell death of the cancer cells with minimal off-target effects. Several hours after NIR-PIT, the tumor vessels become supraphysiologically permeable and circulating APC can therefore readily leak into the already-treated tumor space where it can bind with viable cancer cells that is called super-enhanced permeability and retention effect. The presence of the SUPR effect after NIR-PIT has prompted regimens in which there is a repeat exposure of NIR light 24 hours after the initial NIR-PIT to take advantage of the leakage of additional APC deeper into the tumor. However, this post-treatment APC penetration was fully induced within 3 hours, therefore, it is possible that repeated exposures of NIR light could be administered much earlier than 24 hours and still produce the same effects. To test this idea, we compared several modes of delivering additional doses of light after initial NIR-PIT. We found that repeated exposures of NIR light starting 3 hours after initial NIR-PIT produced equal or superior results to more delayed exposures of NIR light. This finding has practical implications of an easy-to-perform regimen as repeated light exposures could be performed during a single day rather than extending the procedure over two days which is the current recommendation.
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http://dx.doi.org/10.18632/oncotarget.17047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5471035PMC
May 2017

Cerenkov Radiation-Induced Photoimmunotherapy with F-FDG.

J Nucl Med 2017 09 13;58(9):1395-1400. Epub 2017 Apr 13.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland; and

Near-infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with toxicity induced by photoabsorbers after irradiation with NIR light. A limitation of NIR-PIT is the inability to deliver NIR light to a tumor located deep inside the body. Cerenkov radiation (CR) is the ultraviolet and blue light that is produced by a charged particle traveling through a dielectric medium faster than the speed of light in that medium and is commonly produced during radioactive decay. Here, we demonstrate the feasibility of using CR generated by F-FDG accumulated in tumors to induce photoimmunotherapy. Using A431-luc cells, we evaluated the therapeutic effects of CR-PIT in vitro and in vivo using bioluminescence imaging. CR-PIT showed significant suppression of tumor size, but the decrease of bioluminescence after CR-PIT was not observed consistently over the entire time course. Although CR-PIT can induce tumor killing deep within body, it is less effective than NIR-PIT, possibly related to the relatively lower efficiency of short wavelength light than NIR.
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http://dx.doi.org/10.2967/jnumed.116.188789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5577626PMC
September 2017

Near Infrared Photoimmunotherapy in a Transgenic Mouse Model of Spontaneous Epidermal Growth Factor Receptor (EGFR)-expressing Lung Cancer.

Mol Cancer Ther 2017 02 15;16(2):408-414. Epub 2016 Nov 15.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland.

Near infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by a sensitive photoabsorber following exposure to NIR light. Most studies of NIR-PIT have been performed in xenograft models of cancer. The purpose of this study was to evaluate the therapeutic effects of NIR-PIT in a transgenic model of spontaneous lung cancer expressing human EGFR (hEGFR-TL). Mice were separated into 3 groups for the following treatments: (1) no treatment (control); (2) 150 μg of photoabsorber, IR700, conjugated to panitumumab, an antibody targeting EGFR [antibody-photoabsorber conjugate (APC)] intravenously (i.v.) only; (3) 150 μg of APC i.v. with NIR light administration. Each treatment was performed every week up to three weeks. MRI was performed 1 day before and 3, 6, 13, 20, 27, and 34 days after first NIR-PIT. The relative volume of lung tumors was calculated from the tumor volume at each MRI time point divided by the initial volume. Steel test for multiple comparisons was used to compare the tumor volume ratio with that of control. Tumor volume ratio was inhibited significantly in the NIR-PIT group compared with control group (P < 0.01 at all time points). In conclusion, NIR-PIT effectively treated a spontaneous lung cancer in a hEGFR-TL transgenic mouse model. MRI successfully monitored the therapeutic effects of NIR-PIT. Mol Cancer Ther; 16(2); 408-14. ©2016 AACR.
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http://dx.doi.org/10.1158/1535-7163.MCT-16-0663DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5335921PMC
February 2017

Immunogenic cancer cell death selectively induced by near infrared photoimmunotherapy initiates host tumor immunity.

Oncotarget 2017 Feb;8(6):10425-10436

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.

Immunogenic cell death (ICD) is a form of cell death that activates an adaptive immune response against dead-cell-associated antigens. Cancer cells killed via ICD can elicit antitumor immunity. ICD is efficiently induced by near-infrared photo-immunotherapy (NIR-PIT) that selectively kills target-cells on which antibody-photoabsorber conjugates bind and are activated by NIR light exposure. Advanced live cell microscopies showed that NIR-PIT caused rapid and irreversible damage to the cell membrane function leading to swelling and bursting, releasing intracellular components due to the influx of water into the cell. The process also induces relocation of ICD bio markers including calreticulin, Hsp70 and Hsp90 to the cell surface and the rapid release of immunogenic signals including ATP and HMGB1 followed by maturation of immature dendritic cells. Thus, NIR-PIT is a therapy that kills tumor cells by ICD, eliciting a host immune response against tumor.
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http://dx.doi.org/10.18632/oncotarget.14425DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5354669PMC
February 2017

Near-infrared photoimmunotherapy with galactosyl serum albumin in a model of diffuse peritoneal disseminated ovarian cancer.

Oncotarget 2016 Nov;7(48):79408-79416

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland, 20892, USA.

Near-infrared photoimmunotherapy (NIR-PIT) is a highly cell-selective cancer therapy based on an armed antibody conjugated with a phthalocyanine-based photo-absorber, IRDye700DX (IR700). NIR-PIT can quickly kill target cells that express specific proteins on the cellular membrane but only when the antibody-IR700 conjugate binds to the cell membrane and is then exposed to NIR light. NIR-PIT is highly selective based on the specificity of the antibody. Galactosyl serum albumin (GSA) is composed of albumin decorated with galactose molecules conjugated to the carboxyl groups of albumin. GSA binds to beta-D-galactose receptors, a surface lectin, which are overexpressed on the cell surface of many cancers, including ovarian cancers and is quickly internalized after binding. Here, we demonstrate the feasibility of NIR-PIT in a model of disseminated peritoneal ovarian cancer (SHIN3 cells) using GSA-IR700 that binds to beta-D-galactose receptors. GSA-IR700 bound quickly to SHIN3 cells, then accumulated in the endo-lysosomes. Cell-specific killing was observed in vitro, yet a relatively large dose of NIR light exposure was required for cell killing compared to antibody-IR700 conjugates. To evaluate in vivo therapeutic effects of GSA-IR700 NIR-PIT, peritoneal disseminated SHIN3 tumor-bearing mice were separated into four groups: no treatment; NIR light only; GSA-IR700 only; and GSA-IR700 NIR-PIT. Repeated NIR-PIT showed significant suppression of tumor based on bioluminescence compared to the other groups (p < 0.05). Thus, repeated NIR-PIT using GSA-IR700 can achieve efficient antitumor effects, although GSA-IR700 NIR-PIT was less effective than antibody-IR700 NIR-PIT conjugates likely due to the rapid internalization of GSA-IR700.
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http://dx.doi.org/10.18632/oncotarget.12710DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5340234PMC
November 2016

Near infrared photoimmunotherapy with avelumab, an anti-programmed death-ligand 1 (PD-L1) antibody.

Oncotarget 2017 Jan;8(5):8807-8817

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States of America.

Near Infrared-Photoimmunotherapy (NIR-PIT) is a highly selective tumor treatment that employs an antibody-photo-absorber conjugate (APC). Programmed cell death protein-1 ligand (PD-L1) is emerging as a molecular target. Here, we describe the efficacy of NIR-PIT, using fully human IgG1 anti-PD-L1 monoclonal antibody (mAb), avelumab, conjugated to the photo-absorber, IR700DX, in a PD-L1 expressing H441 cell line, papillary adenocarcinoma of lung. Avelumab-IR700 showed specific binding and cell-specific killing was observed after exposure of the cells to NIR in vitro. In the in vivo study, avelumab-IR700 showed high tumor accumulation and high tumor-background ratio. Tumor-bearing mice were separated into 4 groups: (1) no treatment; (2) 100 μg of avelumab-IR700 i.v.; (3) NIR light exposure only, NIR light was administered; (4) 100 μg of avelumab-IR700 i.v., NIR light was administered. Tumor growth was significantly inhibited by NIR-PIT treatment compared with the other groups (p < 0.001), and significantly prolonged survival was achieved (p < 0.01 vs other groups). In conclusion, the anti-PD-L1 antibody, avelumab, is suitable as an APC for NIR-PIT. Furthermore, NIR-PIT with avelumab-IR700 is a promising candidate of the treatment of PD-L1-expressing tumors that could be readily translated to humans.
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http://dx.doi.org/10.18632/oncotarget.12410DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5341755PMC
January 2017

Spatially selective depletion of tumor-associated regulatory T cells with near-infrared photoimmunotherapy.

Sci Transl Med 2016 08;8(352):352ra110

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1002, USA.

Current immunotherapies for cancer seek to modulate the balance among different immune cell populations, thereby promoting antitumor immune responses. However, because these are systemic therapies, they often cause treatment-limiting autoimmune adverse effects. It would be ideal to manipulate the balance between suppressor and effector cells within the tumor without disturbing homeostasis elsewhere in the body. CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) are well-known immunosuppressor cells that play a key role in tumor immunoevasion and have been the target of systemic immunotherapies. We used CD25-targeted near-infrared photoimmunotherapy (NIR-PIT) to selectively deplete Tregs, thus activating CD8 T and natural killer cells and restoring local antitumor immunity. This not only resulted in regression of the treated tumor but also induced responses in separate untreated tumors of the same cell line derivation. We conclude that CD25-targeted NIR-PIT causes spatially selective depletion of Tregs, thereby providing an alternative approach to cancer immunotherapy.
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http://dx.doi.org/10.1126/scitranslmed.aaf6843DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7780242PMC
August 2016

Near infrared photoimmunotherapy of B-cell lymphoma.

Mol Oncol 2016 11 29;10(9):1404-1414. Epub 2016 Jul 29.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, United States. Electronic address:

Near infrared photoimmunotherapy (NIR-PIT) is a new, highly-selective cancer theranostics that employs an antibody-photo absorber conjugate (APC). NIR-PIT has successfully treated preclinical tumor models with APCs and is now in the first-in-human phase 1 clinical trial for head and neck cancer patients against EGFR. CD20 is highly expressed in many B-cell lymphomas and is emerging as a molecular target for this disease. Here, we describe the use of the anti-CD20 monoclonal antibody (mAb), rituximab-IR700 APC for NIR-PIT of B-cell lymphoma in two CD20-expressing lymphoma mouse models. CD20 expressing B-cell lymphoma cell lines (Daudi and Ramos) were used in this study. Rituximab-IR700, rituximab conjugated with IRDye700DX, showed specific binding, and cell-specific killing only after exposure of NIR light to both cells in vitro. To evaluate effects of NIR-PIT in vivo, tumor-bearing mice were separated into 4 groups: (1) control; (2) APC i.v. only; (3) NIR light exposure only; (4) APC and NIR light (NIR-PIT). These were performed every week for up to 3 weeks. Rituximab-IR700 showed high tumor accumulation and high target-to-background ratio in vivo. Tumor growth was significantly inhibited by NIR-PIT in comparison with the other groups (p < 0.001 for both tumors), and survival was significantly prolonged in both tumors (p < 0.001 for Daudi tumors and p < 0.0001 for Ramos tumors vs other groups). More than half of tumors were cured with this single regimen of NIR-PIT. In conclusion, anti-CD20 rituximab-IR700 works as a highly effective APC for NIR-PIT against B-cell lymphoma.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5067212PMC
http://dx.doi.org/10.1016/j.molonc.2016.07.010DOI Listing
November 2016

Effect of charge localization on the in vivo optical imaging properties of near-infrared cyanine dye/monoclonal antibody conjugates.

Mol Biosyst 2016 10 25;12(10):3046-56. Epub 2016 Jul 25.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, USA.

Near-infrared (NIR) fluorophores show superior in vivo imaging properties than visible-light fluorophores because of the increased light penetration in tissue and lower autofluorescence of these wavelengths. We have recently reported that new NIR cyanine dyes containing a novel C4'-O-alkyl linker exhibit greater chemical stability and excellent optical properties relative to existing C4'-O-aryl variants. In this study, we synthesized two NIR cyanine dyes with the same core structure and charge but different indolenine substituents: FNIR-Z-759 bearing a combination of two sulfonates and two quaternary ammonium cations, and FNIR-G-765 bearing a combination of two sulfonates and two guanidines, resulting in zwitterionic charge with distinct cationic moieties. In this study, we compare the in vitro and in vivo optical imaging properties of monoclonal antibody (mAb) conjugates of FNIR-Z-759 and FNIR-G-765 with panitumumab (pan) at antibody-to-dye ratios of 1 : 2 or 1 : 5. One-to-five conjugation of pan-to-FNIR-G-765 was not successful due to aggregate formation during the conjugation reaction. Conjugates of both dyes to pan (2 : 1) demonstrated similar quenching capacity, stability, and brightness in target cells in vitro. However, FNIR-Z-759 conjugates showed significantly lower accumulation in the mouse liver, resulting in higher tumor-to-liver ratio. Thus, FNIR-Z-759 conjugates appear to have superior in vivo imaging characteristics compared with FNIR-G-765 conjugates, especially in the abdominal region. Moreover, from a chemistry point of view, mAb conjugation with FNIR-Z-759 has an advantage over FNIR-G-765, because it does not form aggregates at high dye-to-mAb ratio. These results suggest that zwitterionic cyanine dyes are a superior class of fluorophores for conjugating with mAbs for fluorescence imaging applications due to improving target-to-background contrast in vivo. However, zwitterionic cyanine dyes should be designed carefully, as small changes to the structure can alter in vivo pharmacokinetics of mAb-dye conjugates.
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http://dx.doi.org/10.1039/c6mb00371kDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5030170PMC
October 2016

Alterations of filopodia by near infrared photoimmunotherapy: evaluation with 3D low-coherent quantitative phase microscopy.

Biomed Opt Express 2016 Jul 22;7(7):2738-48. Epub 2016 Jun 22.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, 10 Center Dr. Bethesda,MD 20892, USA.

Filopodia are highly organized cellular membrane structures that facilitate intercellular communication. Near infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that causes necrotic cell death. Three-dimensional low-coherent quantitative phase microscopy (3D LC-QPM) is based on a newly established low-coherent interference microscope designed to obtain serial topographic images of the cellular membrane. Herein, we report rapid involution of filopodia after NIR-PIT using 3D LC-QPM. For 3T3/HER2 cells, the number of filopodia decreased immediately after treatment with significant differences. Volume and relative height of 3T3/HER2 cells increased immediately after NIR light exposure, but significant differences were not observed. Thus, disappearance of filopodia, evaluated by 3D LC-QPM, is an early indicator of cell membrane damage after NIR-PIT.
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http://dx.doi.org/10.1364/BOE.7.002738DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4948626PMC
July 2016

Surgical tissue handling methods to optimize ex vivo fluorescence with the activatable optical probe γ-glutamyl hydroxymethyl rhodamine green.

Contrast Media Mol Imaging 2016 11 22;11(6):572-578. Epub 2016 Jul 22.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD20892, USA.

Optical fluorescence imaging has been developed as an aid to intraoperative diagnosis to improve surgical and endoscopic procedures. Compared with other intraoperative imaging methods, it is lower in cost, has a high safety margin, is portable and easy to use. γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) is a recently developed activatable fluorescence probe that emits strong fluorescence in the presence of the enzyme γ-glutamyl transpeptidase (GGT), which is overexpressed in many cancers, including ovarian cancer. Ex vivo testing is important for clinical approval of such probes. The diagnostic performance of gGlu-HMRG in fresh excised surgical specimens has been reported; however, details of tissue handling have not been optimized. In this study, we investigated four different tissue handling procedures to optimize imaging in excised tumor specimens. The fluorescence intensity time courses after the different tissue handling methods were compared. Additionally, the fluorescence positive areas were correlated with the presence of red fluorescent protein (RFP) in an RFP positive cell line as the standard of reference for cancer location. In the 'intact' groups, tumors yielded quick and homogeneous activation of gGlu-HMRG. In the 'rinse' and 'cut' groups, the fluorescence intensity of the tumor was a little lower than that in the intact group. In the 'pressed' groups, however, fluorescence intensity from gGlu-HMRG was lower over the entire time course, suggesting a decrease or relocation of excreted GGT. In conclusion, we demonstrate that the method of tissue handling prior to ex vivo imaging with the activatable probe gGlu-HMRG has a strong influence on the signal derived from the specimen. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
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http://dx.doi.org/10.1002/cmmi.1705DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6467211PMC
November 2016

Dynamic fluorescent imaging with the activatable probe, γ-glutamyl hydroxymethyl rhodamine green in the detection of peritoneal cancer metastases: Overcoming the problem of dilution when using a sprayable optical probe.

Oncotarget 2016 Aug;7(32):51124-51137

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.

Optical fluorescence-guided imaging is increasingly used to guide surgery and endoscopic procedures. Activatable probes are particularly useful because of high target-to-background ratios that increase sensitivity for tiny cancer foci. However, green fluorescent activatable probes suffer from interference from autofluorescence found in biological tissue. The purpose of this study was to determine if dynamic imaging can be used to differentiate specific fluorescence arising from an activated probe in a tumor from autofluorescence in background tissues especially when low concentrations of the dye are applied. Serial fluorescence imaging was performed using various concentrations of γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) which was sprayed on the peritoneal surface with tiny implants of SHIN3-DsRed ovarian cancer tumors. Temporal differences in signal between specific green fluorescence in cancer foci and non-specific autofluorescence in background tissue were measured at 5, 10, 20 and 30 min after application of gGlu-HMRG and were processed into three kinetic maps reflecting maximum fluorescence signal (MF), wash-in rate (WIR), and area under the curve (AUC), respectively. Using concentrations up to 10 μM of gGlu-HMRG, the fluorescence intensity of cancer foci was significantly higher than that of small intestine but only at 30 min. However, on kinetic maps derived from dynamic fluorescence imaging, the signal of cancer foci was significantly higher than that of small intestine after only 5 min even at concentrations as low as 2.5 μM of gGlu-HMRG (p < 0.01). At lower concentrations, kinetic maps derived from dynamic fluorescence imaging were superior to unprocessed images for cancer detection.
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http://dx.doi.org/10.18632/oncotarget.9898DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5239463PMC
August 2016

Improved micro-distribution of antibody-photon absorber conjugates after initial near infrared photoimmunotherapy (NIR-PIT).

J Control Release 2016 06 5;232:1-8. Epub 2016 Apr 5.

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892 United States. Electronic address:

Near infrared photoimmunotherapy (NIR-PIT), a targeted cancer therapy which uses an antibody-photo absorber conjugate (APC) and near infrared light exposure, dramatically improves nano-drug delivery into treated tumor beds due to enhanced vascular permeability. We investigated the micro-distribution of APCs in a variety of NIR-PIT treated tumors. Either cetuximab (cet) or trastuzumab (tra) conjugated with IR700 (cet-tra-IR700) was administered, as appropriate, to each mouse model of tumor. Tumor-bearing mice implanted with A431-GFP, MDAMB468-GFP, 3T3Her2-GFP or N87-GFP were separated into 5 groups: group 1=no treatment; group 2=cet-tra-IR700 i.v., no light exposure; group 3=cet-tra-IR700 i.v., NIR light exposure; group 4=cet-tra-IR700 i.v. and additional cet-tra-IR700 i.v. at 24h but no light exposure; group 5=cet-tra-IR700 i.v., NIR light exposure and additional cet-tra-IR700 i.v. immediately after NIR but no additional NIR light exposure. In vivo, ex vivo and microscopic fluorescence imaging was performed. Fluorescence from the surface of the tumor (s-tumor) was compared to fluorescence from deeper areas of the tumor (d-tumor). In general, there was no significant difference in the fluorescence intensity of GFP in the tumors among all groups, however the highest IR700 fluorescence intensity was consistently shown in group 5 tumors due to added APC after NIR-PIT. Fluorescence microscopy in all tumor types demonstrated that GFP relative fluorescence intensity (RFI) in s-tumor was significantly lower in group 3 and 5 (NIR-PIT groups) than in group 1, 2, and 4 (no NIR-PIT) yet there was no significant difference in d-tumor RFI among all groups. IR700 fluorescent RFI in the d-tumor was highest in group 5 (NIR-PIT+additional APC) compared to the other groups. Cell killing after NIR-PIT was primarily on the surface, however, APCs administered immediately after NIR-PIT penetrated deeper into tissue resulting in improved cell killing after a 2nd NIR-PIT session. This phenomenon is explained by increased vascular permeability immediately after NIR-PIT.
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http://dx.doi.org/10.1016/j.jconrel.2016.04.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4893891PMC
June 2016

Selective Cell Elimination from Mixed 3D Culture Using a Near Infrared Photoimmunotherapy Technique.

J Vis Exp 2016 Mar 14(109). Epub 2016 Mar 14.

Molecular Imaging Program, National Cancer Institute;

Recent developments in tissue engineering offer innovative solutions for many diseases. For example, tissue engineering using induced pluripotent stem cell (iPS) emerged as a new method in regenerative medicine. Although this tissue regeneration is promising, contamination with unwanted cells during tissue cultures is a major concern. Moreover, there is a safety concern regarding tumorigenicity after transplantation. Therefore, there is an urgent need for eliminating specific cells without damaging other cells that need to be protected, especially in established tissue. Here, we present a method for specific cell elimination from a mixed 3D cell culture in vitro with near infrared photoimmunotherapy (NIR-PIT) without damaging non-targeted cells. This technique enables the elimination of specific cells from mixed cell cultures or tissues.
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http://dx.doi.org/10.3791/53633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4828982PMC
March 2016

Near infrared photoimmunotherapy with an anti-mesothelin antibody.

Oncotarget 2016 Apr;7(17):23361-9

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA.

Near Infrared-Photoimmunotherapy (NIR-PIT) is a new, highly selective tumor treatment that employs an antibody-photon absorber conjugate (APC). When the APC attaches to its target cell and is exposed to NIR light, highly selective cell killing is observed. NIR-PIT has been demonstrated with a limited number of antibodies. Mesothelin is overexpressed in several malignancies and is emerging as a therapeutic target. A recently humanized antibody (hYP218) has been generated against mesothelin that demonstrates high affinity binding. Here, we describe the efficacy of NIR-PIT, using hYP218 as the antibody within the APC to target a mesothelin expressing A431/H9 cell. The hYP218 antibody was conjugated to a photo-absorber, IR700 and incubated with the cells. The hYP218-IR700 showed specific binding to cells and cell-specific killing was observed in vitro. After implanting A431/H9 cells in an athymic nude mouse, tumor-bearing mice were treated with the following regimen of NIR-PIT; 100 μg of hYP218-IR700 i.v., NIR light was administered at 50 J/cm2 on day 1 after injection and 100 J/cm2 of light on day 2 after injection. The hYP218-IR700 showed high tumor accumulation and a high tumor-background ratio (TBR). Tumor growth was significantly inhibited by NIR-PIT treatment compared with the other control groups (p < 0.001), and significantly prolonged survival (p < 0.0001 vs other groups). Thus, the new anti-mesothelin antibody, hYP218, is suitable as an antibody-drug conjugate for NIR-PIT. Furthermore, NIR-PIT with hYP218-IR700 is a promising candidate for the treatment of mesothelin-expressing tumors that could be readily translated to humans.
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http://dx.doi.org/10.18632/oncotarget.8025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5029632PMC
April 2016

Comparative effectiveness of light emitting diodes (LEDs) and Lasers in near infrared photoimmunotherapy.

Oncotarget 2016 Mar;7(12):14324-35

Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA.

Near infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by photosensitizers after exposure to near infrared (NIR) light. Herein we compare two NIR-light sources; light emitting diodes (LEDs) and Lasers, for their effectiveness in NIR-PIT. A photosensitizer, IRDye-700DX, conjugated to panitumumab (pan-IR700), was incubated with EGFR-expressing A431 and MDA-MB-468-luc cells. NIR-light was provided by LEDs or Lasers at the same light dose. Laser-light produced more cytotoxicity and greater reductions in IR700-fluorescence intensity than LED-light. Laser-light also produced more cytotoxicity in vivo in both cell lines. Assessment of super-enhanced permeability and retention (SUPR) effects were stronger with Laser than LED. These results suggest that Laser-light produced significantly more cytotoxic effects compared to LEDs. Although LED is less expensive, Laser-light produces superior results in NIR-PIT.
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http://dx.doi.org/10.18632/oncotarget.7365DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4924718PMC
March 2016