scholarly journals Theranostic PSMA ligands with optimized backbones for intraoperative multimodal imaging and photodynamic therapy of prostate cancer

2022 ◽  
Author(s):  
Yvonne H. W. Derks ◽  
Sanne A. M. van Lith ◽  
Helene I. V. Amatdjais-Groenen ◽  
Lieke W. M. Wouters ◽  
Annemarie Kip ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Imaging ◽  
Multimodal Imaging ◽  
Tumor Targeting ◽  
First Generation ◽  
Solid Phase ◽  
Binding Motif ◽  
High Affinity ◽  
Biodistribution Studies

Abstract  Introduction The first generation ligands for prostate-specific membrane antigen (PSMA)–targeted radio- and fluorescence-guided surgery followed by adjuvant photodynamic therapy (PDT) have already shown the potential of this approach. Here, we developed three new photosensitizer-based dual-labeled PSMA ligands by crucial modification of existing PSMA ligand backbone structures (PSMA-1007/PSMA-617) for multimodal imaging and targeted PDT of PCa. Methods Various new PSMA ligands were synthesized using solid-phase chemistry and provided with a DOTA chelator for 111In labeling and the fluorophore/photosensitizer IRDye700DX. The performance of three new dual-labeled ligands was compared with a previously published first-generation ligand (PSMA-N064) and a control ligand with an incomplete PSMA-binding motif. PSMA specificity, affinity, and PDT efficacy of these ligands were determined in LS174T-PSMA cells and control LS174T wildtype cells. Tumor targeting properties were evaluated in BALB/c nude mice with subcutaneous LS174T-PSMA and LS174T wildtype tumors using µSPECT/CT imaging, fluorescence imaging, and biodistribution studies after dissection. Results In order to synthesize the new dual-labeled ligands, we modified the PSMA peptide linker by substitution of a glutamic acid into a lysine residue, providing a handle for conjugation of multiple functional moieties. Ligand optimization showed that the new backbone structure leads to high-affinity PSMA ligands (all IC50 < 50 nM). Moreover, ligand-mediated PDT led to a PSMA-specific decrease in cell viability in vitro (P < 0.001). Linker modification significantly improved tumor targeting compared to the previously developed PSMA-N064 ligand (≥ 20 ± 3%ID/g vs 14 ± 2%ID/g, P < 0.01) and enabled specific visualization of PMSA-positive tumors using both radionuclide and fluorescence imaging in mice. Conclusion The new high-affinity dual-labeled PSMA-targeting ligands with optimized backbone compositions showed increased tumor targeting and enabled multimodal image-guided PCa surgery combined with targeted photodynamic therapy.

scholarly journals Strain-Promoted Azide-Alkyne Cycloaddition-Based PSMA-Targeting Ligands For Multimodal Intraoperative Tumor Detection of Prostate Cancer

2021 ◽  
Author(s):  
Yvonne H.W. Derks ◽  
Mark Rijpkema ◽  
Helene I.V. Amatdjais-Groenen ◽  
Cato Loeff ◽  
Kim E. de Roode ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Fluorescence Imaging ◽  
Tumor Targeting ◽  
Solid Phase ◽  
Biodistribution Studies ◽  
Specific Tumor ◽  
Multiple Imaging ◽  
Specific Accumulation ◽  
Modular Platform

Abstract Purpose: Strain-promoted azide-alkyne cycloaddition (SPAAC) is a straightforward and multipurpose conjugation strategy. Use of SPAAC to link different functional elements to prostate specific membrane antigen (PSMA) ligands would facilitate the development of a modular platform for PSMA-targeted imaging and therapy of prostate cancer (PCa). As a first proof-of-concept for the SPAAC chemistry platform we synthesized and characterized four dual-labeled PSMA ligands for intraoperative radiodetection and fluorescence imaging of PCa. Methods: Ligands were synthesized using solid phase chemistry and contained a chelator for 111In or 99mTc labeling. The fluorophore IRDye800CW was conjugated using SPAAC chemistry or conventional N-hydroxysuccinimide (NHS)-ester coupling. LogD values were measured and PSMA-specificity of these ligands was determined in LS174T-PSMA cells. Tumor targeting was evaluated in BALB/c nude mice with subcutaneous LS174T-PSMA and LS174T wildtype tumors using µSPECT/CT imaging, fluorescence imaging, and biodistribution studies. Results: SPAAC chemistry increased lipophilicity of the ligands (range LogD: -2.4 to -4.4). In vivo, SPAAC chemistry ligands showed high and specific accumulation in s.c. LS174T-PSMA tumors up to 24 hours after injection, enabling clear visualization using µSPECT/CT and fluorescence imaging. Overall, no significant differences between the SPAAC chemistry ligands and their NHS-based counterparts were found (2 h p.i., p > 0.05), while 111In-labeled ligands outperformed the 99mTc ligands. Conclusion: Here we demonstrate that our newly developed SPAAC-based PSMA ligands show high PSMA-specific tumor targeting. Use of click-chemistry in PSMA ligand development opens up the opportunity for fast, efficient and versatile conjugations of multiple imaging moieties and/or drugs.

Fluorinated cryptophane-A and porphyrin-based theranostics for multimodal imaging-guided photodynamic therapy

2020 ◽  
Vol 56 (25) ◽  
pp. 3617-3620
Author(s):  
Huaibin Zhang ◽  
Qiao Yu ◽  
Yu Li ◽  
Zhigang Yang ◽  
Xin Zhou ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Imaging ◽  
Multimodal Imaging ◽  
Tumor Detection ◽  
Cest Mri

Herein, we developed fluorinated nanoemulsions with significantly enhanced in vitro and in vivo129Xe hyper-CEST MRI, 19F MRI and fluorescence imaging signals for selective and sensitive tumor detection and NIR-activated photodynamic therapy.

68Ga-labeled HBED-CC Variant of uPAR Targeting Peptide AE105 Compared with 68Ga-NODAGA-AE105

2019 ◽  
Vol 18 (9) ◽  
pp. 1289-1294 ◽  
Author(s):  
Kusum Vats ◽  
Rohit Sharma ◽  
Haladhar D. Sarma ◽  
Drishty Satpati ◽  
Ashutosh Dash
Keyword(s):  
Solid Phase ◽  
Evaluation Studies ◽  
Radiochemical Yield ◽  
In Vivo Evaluation ◽  
Peptide Conjugates ◽  
Biodistribution Studies ◽  
Target Organs ◽  
U87mg Tumor

Aims: The urokinase Plasminogen Activator Receptors (uPAR) over-expressed on tumor cells and their invasive microenvironment are clinically significant molecular targets for cancer research. uPARexpressing cancerous lesions can be suitably identified and their progression can be monitored with radiolabeled uPAR targeted imaging probes. Hence this study aimed at preparing and evaluating two 68Ga-labeled AE105 peptide conjugates, 68Ga-NODAGA-AE105 and 68Ga-HBED-CC-AE105 as uPAR PET-probes. Method: The peptide conjugates, HBED-CC-AE105-NH2 and NODAGA-AE105-NH2 were manually synthesized by standard Fmoc solid phase strategy and subsequently radiolabeled with 68Ga eluted from a commercial 68Ge/68Ga generator. In vitro cell studies for the two radiotracers were performed with uPAR positive U87MG cells. Biodistribution studies were carried out in mouse xenografts with the subcutaneously induced U87MG tumor. Results: The two radiotracers, 68Ga-NODAGA-AE105 and 68Ga-HBED-CC-AE105 that were prepared in >95% radiochemical yield and >96% radiochemical purity, exhibited excellent in vitro stability. In vivo evaluation studies revealed higher uptake of 68Ga-HBED-CC-AE105 in U87MG tumor as compared to 68Ga-NODAGAAE105; however, increased lipophilicity of 68Ga-HBED-CC-AE105 resulted in slower clearance from blood and other non-target organs. The uPAR specificity of the two radiotracers was ascertained by significant (p<0.05) reduction in the tumor uptake with a co-injected blocking dose of unlabeled AE-105 peptide. Conclusion: Amongst the two radiotracers studied, the neutral 68Ga-NODAGA-AE105 with more hydrophilic chelator exhibited faster clearance from non-target organs. The conjugation of HBED-CC chelator (less hydrophilic) resulted in negatively charged 68Ga-HBED-CC-AE105 which was observed to have high retention in blood that decreased target to non-target ratios.

scholarly journals 68Ga, 44Sc and 177Lu-labeled AAZTA5-PSMA-617: synthesis, radiolabeling, stability and cell binding compared to DOTA-PSMA-617 analogues

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Jean-Philippe Sinnes ◽  
Ulrike Bauder-Wüst ◽  
Martin Schäfer ◽  
Euy Sung Moon ◽  
Klaus Kopka ◽  
...  
Keyword(s):  
Human Serum ◽  
Room Temperature ◽  
Solid Phase ◽  
Negative Influence ◽  
Binding Motif ◽  
Lncap Cells ◽  
Cell Binding ◽  
Binding Characteristics

Abstract Background The AAZTA chelator and in particular its bifunctional derivative AAZTA5 was recently investigated to demonstrate unique capabilities to complex diagnostic and therapeutic trivalent radiometals under mild conditions. This study presents a comparison of 68Ga, 44Sc and 177Lu-labeled AAZTA5-PSMA-617 with DOTA-PSMA-617 analogues. We evaluated the radiolabeling characteristics, in vitro stability of the radiolabeled compounds and evaluated their binding affinity and internalization behavior on LNCaP tumor cells in direct comparison to the radiolabeled DOTA-conjugated PSMA-617 analogs. Results AAZTA5 was synthesized in a five-step synthesis and coupled to the PSMA-617 backbone on solid phase. Radiochemical evaluation of AAZTA5-PSMA-617 with 68Ga, 44Sc and 177Lu achieved quantitative radiolabeling of > 99% after less than 5 min at room temperature. Stabilities against human serum, PBS buffer and EDTA and DTPA solutions were analyzed. While there was a small degradation of the 68Ga complex over 2 h in human serum, PBS and EDTA/DTPA, the 44Sc and 177Lu complexes were stable at 2 h and remained stable over 8 h and 1 day. For all three compounds, i.e. [natGa]Ga-AAZTA5-PSMA-617, [natSc]Sc-AAZTA5-PSMA-617 and [natLu]Lu-AAZTA5-PSMA-617, in vitro studies on PSMA-positive LNCaP cells were performed in direct comparison to radiolabeled DOTA-PSMA-617 yielding the corresponding inhibition constants (Ki). Ki values were in the range of 8–31 nM values which correspond with those of [natGa]Ga-DOTA-PSMA-617, [natSc]Sc-DOTA-PSMA-617 and [natLu]Lu-DOTA-PSMA-617, i.e. 5–7 nM, respectively. Internalization studies demonstrated cellular membrane to internalization ratios for the radiolabeled 68Ga, 44Sc and 177Lu-AAZTA5-PSMA-617 tracers (13–20%IA/106 cells) in the same range as the ones of the three radiolabeled DOTA-PSMA-617 tracers (17–20%IA/106 cells) in the same assay. Conclusions The AAZTA5-PSMA-617 structure proved fast and quantitative radiolabeling with all three radiometal complexes at room temperature, excellent stability with 44Sc, very high stability with 177Lu and medium stability with 68Ga in human serum, PBS and EDTA/DTPA solutions. All three AAZTA5-PSMA-617 tracers showed binding affinities and internalization ratios in LNCaP cells comparable with that of radiolabeled DOTA-PSMA-617 analogues. Therefore, the exchange of the chelator DOTA with AAZTA5 within the PSMA-617 binding motif has no negative influence on in vitro LNCaP cell binding characteristics. In combination with the faster and milder radiolabeling features, AAZTA5-PSMA-617 thus demonstrates promising potential for in vivo application for theranostics of prostate cancer.

scholarly journals Design of PSMA ligands with modifications at the inhibitor part: an approach to reduce the salivary gland uptake of radiolabeled PSMA inhibitors?

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Veronika Barbara Felber ◽  
Manuel Amando Valentin ◽  
Hans-Jürgen Wester
Keyword(s):  
Salivary Gland ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
In Vivo Studies ◽  
Tumor Xenograft ◽  
Tumor Uptake ◽  
Lncap Cells ◽  
High Affinity

Abstract Aim To investigate whether modifications of prostate-specific membrane antigen (PSMA)-targeted radiolabeled urea-based inhibitors could reduce salivary gland uptake and thus improve tumor-to-salivary gland ratios, several analogs of a high affinity PSMA ligand were synthesized and evaluated in in vitro and in vivo studies. Methods Binding motifs were synthesized ‘on-resin’ or, when not practicable, in solution. Peptide chain elongations were performed according to optimized standard protocols via solid-phase peptide synthesis. In vitro experiments were performed using PSMA+ LNCaP cells. In vivo studies as well as μSPECT/CT scans were conducted with male LNCaP tumor xenograft-bearing CB17-SCID mice. Results PSMA ligands with A) modifications within the central Zn2+-binding unit, B) proinhibitor motifs and C) substituents & bioisosteres of the P1′-γ-carboxylic acid were synthesized and evaluated. Modifications within the central Zn2+-binding unit of PSMA-10 (Glu-urea-Glu) provided three compounds. Thereof, only natLu-carbamate I (natLu-3) exhibited high affinity (IC50 = 7.1 ± 0.7 nM), but low tumor uptake (5.31 ± 0.94% ID/g, 1 h p.i. and 1.20 ± 0.55% ID/g, 24 h p.i.). All proinhibitor motif-based ligands (three in total) exhibited low binding affinities (> 1 μM), no notable internalization and very low tumor uptake (< 0.50% ID/g). In addition, four compounds with P1′-ɣ-carboxylate substituents were developed and evaluated. Thereof, only tetrazole derivative natLu-11 revealed high affinity (IC50 = 16.4 ± 3.8 nM), but also this inhibitor showed low tumor uptake (3.40 ± 0.63% ID/g, 1 h p.i. and 0.68 ± 0.16% ID/g, 24 h p.i.). Salivary gland uptake in mice remained at an equally low level for all compounds (between 0.02 ± 0.00% ID/g and 0.09 ± 0.03% ID/g), wherefore apparent tumor-to-submandibular gland and tumor-to-parotid gland ratios for the modified peptides were distinctly lower (factor 8–45) than for [177Lu]Lu-PSMA-10 at 24 h p.i. Conclusions The investigated compounds could not compete with the in vivo characteristics of the EuE-based PSMA inhibitor [177Lu]Lu-PSMA-10. Although two derivatives (3 and 11) were found to exhibit high affinities towards LNCaP cells, tumor uptake at 24 h p.i. was considerably low, while uptake in salivary glands remained unaffected. Optimization of the established animal model should be envisaged to enable a clear identification of PSMA-targeting radioligands with improved tumor-to-salivary gland ratios in future studies.

scholarly journals Biocompatible conjugated fluorenylporphyrins for two-photon photodynamic therapy and fluorescence imaging

2019 ◽  
Vol 55 (81) ◽  
pp. 12231-12234 ◽  
Author(s):  
Limiao Shi ◽  
Christophe Nguyen ◽  
Morgane Daurat ◽  
Abdelhamid Chiheb Dhieb ◽  
Wajda Smirani ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Photodynamic Therapy ◽  
Cancer Cells ◽  
Fluorescence Imaging ◽  
Breast Cancer Cells ◽  
Two Photon ◽  
Theranostic Applications

Three new biocompatible porphyrin-based oxygen photosensitisers were tested in vitro on breast cancer cells via 2P-PDT: one of them, 66 times more active than H2TPP, gave quite promising results for theranostic applications.

scholarly journals Improved Tumor-Targeting with Peptidomimetic Analogs of Minigastrin 177Lu-PP-F11N

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2629
Author(s):  
Nathalie M. Grob ◽  
Roger Schibli ◽  
Martin Béhé ◽  
Thomas L. Mindt
Keyword(s):  
Tumor Targeting ◽  
Amide Bond ◽  
Amide Bonds ◽  
Structural Modifications ◽  
The Past ◽  
Cell Internalization ◽  
Biodistribution Studies ◽  
Metabolic Degradation

The cholecystokinin-2 receptor (CCK2R) is an attractive target in nuclear medicine due to its overexpression by different tumors. Several radiolabeled peptidic ligands targeting the CCK2R have been investigated in the past; however, their low stability against proteases can limit their uptake in tumors and metastases. Substitution of single or multiple amide bonds with metabolically stable 1,4-disubstituted 1,2,3-triazoles as amide bond bioisosteres proved a promising strategy for improving the tumor-targeting properties of a truncated analog of minigastrin. In this study, we applied the previously studied structural modifications to improve the pharmacokinetic and pharmacodynamic properties of PP-F11N, a minigastrin analog currently in clinical trials. Novel minigastrins (NMGs) as analogs of PP-F11N with one or two amide bonds substituted by 1,2,3-triazoles were synthesized, radiolabeled with 177Lu3+, and subjected to full evaluation in vitro (cell internalization, receptor affinity, stability in blood plasma) and in vivo (stability, biodistribution, SPECT/CT imaging). NMGs with triazoles inserted between the amino acids DGlu10-Ala11 and/or Tyr12-Gly13 showed a significantly increased cellular uptake and affinity toward the CCK2R in vitro. Resistance against the metabolic degradation of the NMGs was comparable to those of the clinical candidate PP-F11N. Imaging by SPECT/CT and biodistribution studies demonstrated a higher uptake in CCK2R-positive tumors but also in the CCK2R-positive stomach. The peptidomimetic compounds showed a slow tumor washout and high tumor-to-kidney ratios. The structural modifications led to the identification of analogs with promising properties for progression to clinical applications in the diagnosis and therapy of CCK2R-positive neoplasms.

scholarly journals Capacity of simian immunodeficiency virus strain mac Nef for high-affinity Src homology 3 (SH3) binding revealed by ligand-tailored SH3 domains

2002 ◽  
Vol 83 (12) ◽  
pp. 3147-3152 ◽  
Author(s):  
Marita Hiipakka ◽  
Kalle Saksela
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Binding Motif ◽  
Sh3 Domains ◽  
Src Homology 3 ◽  
High Affinity ◽  
Loop Region ◽  
Immunodeficiency Virus ◽  
Src Homology ◽  
Hiv 1

The simian immunodeficiency virus (SIV) Nef protein contains a consensus Src-homology 3 (SH3) binding motif. However, no SH3-domain proteins showing strong binding to SIV Nef have yet been found, and its potential capacity for high-affinity SH3 binding has therefore remained unproven. Here we have used phage-display-assisted protein engineering to develop artificial SH3 domains that bind tightly to SIV strain mac (SIVmac) Nef. Substitution of six amino acids in the RT loop region of Hck-SH3 with the sequence E/DGWWG resulted in SH3 domains that bound in vitro to SIVmac Nef much better than the natural Hck- or Fyn-SH3 domains. These novel SH3 domains also efficiently associated with SIVmac Nef when co-expressed in 293T cells and displayed a strikingly differential specificity when compared with SH3 domains similarly targeted for binding to human immunodeficiency virus type 1 (HIV-1) Nef. Thus, SIVmac Nef is competent for high-affinity SH3 binding, but its natural SH3 protein partners are likely to be different from those of HIV-1 Nef.

A redox-responsive mesoporous silica based nanoplatform for in vitro tumor-specific fluorescence imaging and enhanced photodynamic therapy

2018 ◽  
Vol 6 (1) ◽  
pp. 96-100 ◽  
Author(s):  
Fan Yuan ◽  
Jiang-Lan Li ◽  
Han Cheng ◽  
Xuan Zeng ◽  
Xian-Zheng Zhang
Keyword(s):  
Photodynamic Therapy ◽  
Tumor Microenvironment ◽  
Mesoporous Silica ◽  
Fluorescence Imaging ◽  
Silica Nanoparticle ◽  
Mesoporous Silica Nanoparticle ◽  
Specific Fluorescence ◽  
Redox Responsive ◽  
Multifunctional Peptides

A mesoporous silica nanoparticle-based redox-responsive platform modified with multifunctional peptides was successfully developed for in vitro tumor microenvironment-enhanced photodynamic therapy.

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