scholarly journals Site-Specific Dual-Labeling of a VHH with a Chelator and a Photosensitizer for Nuclear Imaging and Targeted Photodynamic Therapy of EGFR-Positive Tumors

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 428
Author(s):  
Emma Renard ◽  
Estel Collado Camps ◽  
Coline Canovas ◽  
Annemarie Kip ◽  
Martin Gotthardt ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Imaging ◽  
Ex Vivo ◽  
Growth Factor Receptor ◽  
Nuclear Imaging ◽  
A431 Cells ◽  
Site Specific ◽  
Variable Domains ◽  
Diagnostic Probe

Variable domains of heavy chain only antibodies (VHHs) are valuable agents for application in tumor theranostics upon conjugation to both a diagnostic probe and a therapeutic compound. Here, we optimized site-specific conjugation of the chelator DTPA and the photosensitizer IRDye700DX to anti-epidermal growth factor receptor (EGFR) VHH 7D12, for applications in nuclear imaging and photodynamic therapy. 7D12 was site-specifically equipped with bimodal probe DTPA-tetrazine-IRDye700DX using the dichlorotetrazine conjugation platform. Binding, internalization and light-induced toxicity of DTPA-IRDye700DX-7D12 were determined using EGFR-overexpressing A431 cells. Finally, ex vivo biodistribution of DTPA-IRDye700DX-7D12 in A431 tumor-bearing mice was performed, and tumor homing was visualized with SPECT and fluorescence imaging. DTPA-IRDye700DX-7D12 was retrieved with a protein recovery of 43%, and a degree of labeling of 0.56. Spectral properties of the IRDye700DX were retained upon conjugation. 111In-labeled DTPA-IRDye700DX-7D12 bound specifically to A431 cells, and they were effectively killed upon illumination. DTPA-IRDye700DX-7D12 homed to A431 xenografts in vivo, and this could be visualized with both SPECT and fluorescence imaging. In conclusion, the dichlorotetrazine platform offers a feasible method for site-specific dual-labeling of VHH 7D12, retaining binding affinity and therapeutic efficacy. The flexibility of the described approach makes it easy to vary the nature of the probes for other combinations of diagnostic and therapeutic compounds.

scholarly journals Visualisation of interstitial lung disease by molecular imaging of integrin αvβ3 and somatostatin receptor 2

2018 ◽  
Vol 78 (2) ◽  
pp. 218-227 ◽  
Author(s):  
Janine Schniering ◽  
Martina Benešová ◽  
Matthias Brunner ◽  
Stephanie Haller ◽  
Susan Cohrs ◽  
...  
Keyword(s):  
Interstitial Lung Disease ◽  
Lung Disease ◽  
Single Photon ◽  
Ex Vivo ◽  
Somatostatin Receptor ◽  
Photon Emission ◽  
Nuclear Imaging ◽  
Integrin Αvβ3 ◽  
Biodistribution Studies

ObjectiveTo evaluate integrin αvβ3 (alpha-v-beta-3)-targeted and somatostatin receptor 2 (SSTR2)-targeted nuclear imaging for the visualisation of interstitial lung disease (ILD).MethodsThe pulmonary expression of integrin αvβ3 and SSTR2 was analysed in patients with different forms of ILD as well as in bleomycin (BLM)-treated mice and respective controls using immunohistochemistry. Single photon emission CT/CT (SPECT/CT) was performed on days 3, 7 and 14 after BLM instillation using the integrin αvβ3-targeting 177Lu-DOTA-RGD and the SSTR2-targeting 177Lu-DOTA-NOC radiotracer. The specific pulmonary accumulation of the radiotracers over time was assessed by in vivo and ex vivo SPECT/CT scans and by biodistribution studies.ResultsExpression of integrin αvβ3 and SSTR2 was substantially increased in human ILD regardless of the subtype. Similarly, in lungs of BLM-challenged mice, but not of controls, both imaging targets were stage-specifically overexpressed. While integrin αvβ3 was most abundantly upregulated on day 7, the inflammatory stage of BLM-induced lung fibrosis, SSTR2 expression peaked on day 14, the established fibrotic stage. In agreement with the findings on tissue level, targeted nuclear imaging using SPECT/CT specifically detected both imaging targets ex vivo and in vivo, and thus visualised different stages of experimental ILD.ConclusionOur preclinical proof-of-concept study suggests that specific visualisation of molecular processes in ILD by targeted nuclear imaging is feasible. If transferred into clinics, where imaging is considered an integral part of patients’ management, the additional information derived from specific imaging tools could represent a first step towards precision medicine in ILD.

scholarly journals Absorption by water increases fluorescence image contrast of biological tissue in the shortwave infrared

2018 ◽  
Vol 115 (37) ◽  
pp. 9080-9085 ◽  
Author(s):  
Jessica A. Carr ◽  
Marianne Aellen ◽  
Daniel Franke ◽  
Peter T. C. So ◽  
Oliver T. Bruns ◽  
...  
Keyword(s):  
Penetration Depth ◽  
Fluorescence Imaging ◽  
Biological Tissue ◽  
Ex Vivo ◽  
Scattered Light ◽  
Image Contrast ◽  
Fluorescence Image ◽  
Tissue Phantoms ◽  
Shortwave Infrared

Recent technology developments have expanded the wavelength window for biological fluorescence imaging into the shortwave infrared. We show here a mechanistic understanding of how drastic changes in fluorescence imaging contrast can arise from slight changes of imaging wavelength in the shortwave infrared. We demonstrate, in 3D tissue phantoms and in vivo in mice, that light absorption by water within biological tissue increases image contrast due to attenuation of background and highly scattered light. Wavelengths of strong tissue absorption have conventionally been avoided in fluorescence imaging to maximize photon penetration depth and photon collection, yet we demonstrate that imaging at the peak absorbance of water (near 1,450 nm) results in the highest image contrast in the shortwave infrared. Furthermore, we show, through microscopy of highly labeled ex vivo biological tissue, that the contrast improvement from water absorption enables resolution of deeper structures, resulting in a higher imaging penetration depth. We then illustrate these findings in a theoretical model. Our results suggest that the wavelength-dependent absorptivity of water is the dominant optical property contributing to image contrast, and is therefore crucial for determining the optimal imaging window in the infrared.

scholarly journals Enhancement in Site-Specific Delivery of Carvacrol against Methicillin Resistant Staphylococcus aureus Induced Skin Infections Using Enzyme Responsive Nanoparticles: A Proof of Concept Study

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 606 ◽  
Author(s):  
Maria Mir ◽  
Naveed Ahmed ◽  
Andi Dian Permana ◽  
Aoife Maria Rodgers ◽  
Ryan F. Donnelly ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Ex Vivo ◽  
Infection Model ◽  
Skin Infections ◽  
Site Specific ◽  
Methicillin Resistant ◽  
Hydrogel Matrix ◽  
Skin Retention

Methicillin resistant Staphylococcus aureus (MRSA) induced skin infections have become a challenging problem due to the escalating antibiotic resistance. Carvacrol (CAR) has been reported to be effective against MRSA. However, due to its characteristics, CAR exhibits low skin retention. In this study, CAR was formulated into site-specific nanoparticle (NPs) delivery system using poly(ε-caprolactone) (PCL), following incorporation into a hydrogel matrix to facilitate dermal delivery. The release study exhibited significantly higher release of CAR from PCL NPs in the presence of bacterial lipase, highlighting its potential for differential delivery. Moreover, encapsulation of CAR in PCL NPs resulted in a two-fold increase in its anti-MRSA activity. Dermatokinetic studies revealed that the NPs loaded hydrogel was able to enhance skin retention of CAR after 24 h (83.29 ± 3.15%), compared to free CAR-loaded hydrogel (0.85 ± 0.14%). Importantly, this novel approach exhibited effective antimicrobial activity in an ex-vivo skin infection model. Hence, these findings have proven the concept that the loading of CAR into a responsive NPs system can lead to sustained antimicrobial effect at the desired site, and may provide a novel effective approach for treatment of MRSA induced skin infections. However, further studies must be conducted to investigate in-vivo efficacy of the developed system in an appropriate infection model.

IN VIVO NEAR-INFRARED FLUORESCENCE IMAGING OF HUMAN COLON ADENOCARCINOMA BY SPECIFIC IMMUNOTARGETING OF A TUMOR-ASSOCIATED MUCIN

2009 ◽  
Vol 02 (04) ◽  
pp. 407-422 ◽  
Author(s):  
RALPH S. DACOSTA ◽  
YING TANG ◽  
TUULA KALLIOMAKI ◽  
RAYMOND M. REILLY ◽  
ROBERT WEERSINK ◽  
...  
Keyword(s):  
Fluorescence Microscopy ◽  
Fluorescence Imaging ◽  
Normal Tissue ◽  
Near Infrared ◽  
Ex Vivo ◽  
Colon Adenocarcinoma ◽  
Human Colon ◽  
Human Colon Adenocarcinoma

Background and Aims: Accurate endoscopic detection of premalignant lesions and early cancers in the colon is essential for cure, since prognosis is closely related to lesion size and stage. Although it has great clinical potential, autofluorescence endoscopy has limited tumor-to-normal tissue image contrast for detecting small preneoplastic lesions. We have developed a molecularly specific, near-infrared fluorescent monoclonal antibody (CC49) bioconjugate which targets tumor-associated glycoprotein 72 (TAG72), as a contrast agent to improve fluorescence-based endoscopy of colon cancer. Methods: The fluorescent anti-TAG72 conjugate was evaluated in vitro and in vivo in athymic nude mice bearing human colon adenocarcinoma (LS174T) subcutaneous tumors. Autofluorescence, a fluorescent but irrelevant antibody and the free fluorescent dye served as controls. Fluorescent agents were injected intravenously, and in vivo whole body fluorescence imaging was performed at various time points to determine pharmacokinetics, followed by ex vivo tissue analysis by confocal fluorescence microscopy and histology. Results: Fluorescence microscopy and histology confirmed specific LS174T cell membrane targeting of labeled CC49 in vitro and ex vivo. In vivo fluorescence imaging demonstrated significant tumor-to-normal tissue contrast enhancement with labeled-CC49 at three hours post injection, with maximum contrast after 48 h. Accumulation of tumor fluorescence demonstrated that modification of CC49 antibodies did not alter their specific tumor-localizing properties, and was antibody-dependent since controls did not produce detectable tumor fluorescence. Conclusions: These results show proof-of-principle that our near-infrared fluorescent-antibody probe targeting a tumor-associated mucin detects colonic tumors at the molecular level in real time, and offer a basis for future improvement of image contrast during clinical fluorescence endoscopy.

One small molecule as a theranostic agent: naphthalimide dye for subcellular fluorescence localization and photodynamic therapy in vivo

MedChemComm ◽  
2016 ◽  
Vol 7 (6) ◽  
pp. 1171-1175 ◽  
Author(s):  
Lei Zhang ◽  
Kecheng Lei ◽  
Jingwen Zhang ◽  
Wenlin Song ◽  
Yuanhong Zheng ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Imaging ◽  
Small Molecule ◽  
Single Molecule ◽  
Therapeutic Treatment ◽  
Agent Based ◽  
Theranostic Agent ◽  
Bright Fluorescence ◽  
Naphthalimide Dye

A small single-molecule theranostic agent based on naphthalimide was developed, which possessed both bright fluorescence imaging and effective photodynamic therapeutic treatment.

scholarly journals Synthesis of site-specific antibody-drug conjugates by ADP-ribosyl cyclases

2020 ◽  
Vol 6 (23) ◽  
pp. eaba6752 ◽  
Author(s):  
Zhefu Dai ◽  
Xiao-Nan Zhang ◽  
Fariborz Nasertorabi ◽  
Qinqin Cheng ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Growth Factor Receptor ◽  
Reaction Times ◽  
Single Step ◽  
Her2 Positive ◽  
Site Specific ◽  
Antibody Drug Conjugates ◽  
Drug Conjugates ◽  
Antibody Drug

Most of the current antibody-drug conjugates (ADCs) in clinic are heterogeneous mixtures. To produce homogeneous ADCs, established procedures often require multiple steps or long reaction times. The introduced mutations or foreign sequences may cause high immunogenicity. Here, we explore a new concept of transforming CD38 enzymatic activity into a facile approach for generating site-specific ADCs. This was achieved through coupling bifunctional antibody-CD38 fusion proteins with designer dinucleotide-based covalent inhibitors with stably attached payloads. The resulting adenosine diphosphate–ribosyl cyclase–enabled ADC (ARC-ADC) with a drug-to-antibody ratio of 2 could be rapidly generated through single-step conjugation. The generated ARC-ADC targeting human epidermal growth factor receptor 2 (HER2) displays excellent stability and potency against HER2-positive breast cancer both in vitro and in vivo. This proof-of-concept study demonstrates a new strategy for production of site-specific ADCs. It may provide a general approach for the development of a novel class of ADCs with potentially enhanced properties.

scholarly journals Targeted photodynamic therapy selectively kills activated fibroblasts in experimental arthritis

Rheumatology ◽  
2020 ◽  
Vol 59 (12) ◽  
pp. 3952-3960 ◽  
Author(s):  
Daphne N Dorst ◽  
Mark Rijpkema ◽  
Marti Boss ◽  
Birgitte Walgreen ◽  
Monique M A Helsen ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Therapeutic Potential ◽  
Ex Vivo ◽  
Synovial Fibroblasts ◽  
Knee Joints ◽  
Specific Cell ◽  
Collagen Induced Arthritis ◽  
Targeted Photodynamic Therapy

Abstract Objective In RA, synovial fibroblasts become activated. These cells express fibroblast activation protein (FAP) and contribute to the pathogenesis by producing cytokines, chemokines and proteases. Selective depletion in inflamed joints could therefore constitute a viable treatment option. To this end, we developed and tested a new therapeutic strategy based on the selective destruction of FAP-positive cells by targeted photodynamic therapy (tPDT) using the anti-FAP antibody 28H1 coupled to the photosensitizer IRDye700DX. Methods After conjugation of IRDye700DX to 28H1, the immunoreactive binding and specificity of the conjugate were determined. Subsequently, tPDT efficiency was established in vitro using a 3T3 cell line stably transfected with FAP. The biodistribution of [111In]In-DTPA-28H1 with and without IRDye700DX was assessed in healthy C57BL/6N mice and in C57BL/6N mice with antigen-induced arthritis. The potential of FAP-tPDT to induce targeted damage was determined ex vivo by treating knee joints from C57BL/6N mice with antigen-induced arthritis 24 h after injection of the conjugate. Finally, the effect of FAP-tPDT on arthritis development was determined in mice with collagen-induced arthritis. Results 28H1-700DX was able to efficiently induce FAP-specific cell death in vitro. Accumulation of the anti-FAP antibody in arthritic knee joints was not affected by conjugation with the photosensitizer. Arthritis development was moderately delayed in mice with collagen-induced arthritis after FAP-tPDT. Conclusion Here we demonstrate the feasibility of tPDT to selectively target and kill FAP-positive fibroblasts in vitro and modulate arthritis in vivo using a mouse model of RA. This approach may have therapeutic potential in (refractory) arthritis.

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