scholarly journals Design, Synthesis and Preclinical Assessment of 99mTc-iFAP for In Vivo Fibroblast Activation Protein (FAP) Imaging

Molecules ◽  
2022 ◽  
Vol 27 (1) ◽  
pp. 264
Author(s):  
Diana Trujillo-Benítez ◽  
Myrna Luna-Gutiérrez ◽  
Guillermina Ferro-Flores ◽  
Blanca Ocampo-García ◽  
Clara Santos-Cuevas ◽  
...  
Keyword(s):  
Human Serum ◽  
Boronic Acid ◽  
Human Fibroblasts ◽  
Fibroblast Activation Protein ◽  
Size Exclusion ◽  
Tumor Uptake ◽  
Endometrial Cells ◽  
Fibroblast Activation

Fibroblast activation protein (FAP) is expressed in the microenvironment of most human epithelial tumors. 68Ga-labeled FAP inhibitors based on the cyanopyrrolidine structure (FAPI) are currently used for the detection of the tumor microenvironment by PET imaging. This research aimed to design, synthesize and preclinically evaluate a new FAP inhibitor radiopharmaceutical based on the 99mTc-((R)-1-((6-hydrazinylnicotinoyl)-D-alanyl) pyrrolidin-2-yl) boronic acid (99mTc-iFAP) structure for SPECT imaging. Molecular docking for affinity calculations was performed using the AutoDock software. The chemical synthesis was based on a series of coupling reactions of 6-hidrazinylnicotinic acid (HYNIC) and D-alanine to a boronic acid derivative. The iFAP was prepared as a lyophilized formulation based on EDDA/SnCl2 for labeling with 99mTc. The radiochemical purity (R.P.) was verified via ITLC-SG and reversed-phase radio-HPLC. The stability in human serum was evaluated by size-exclusion HPLC. In vitro cell uptake was assessed using N30 stromal endometrial cells (FAP positive) and human fibroblasts (FAP negative). Biodistribution and tumor uptake were determined in Hep-G2 tumor-bearing nude mice, from which images were acquired using a micro-SPECT/CT. The iFAP ligand (Ki = 0.536 nm, AutoDock affinity), characterized by UV-Vis, FT-IR, 1H–NMR and UPLC-mass spectroscopies, was synthesized with a chemical purity of 92%. The 99mTc-iFAP was obtained with a R.P. >98%. In vitro and in vivo studies indicated high radiotracer stability in human serum (>95% at 24 h), specific recognition for FAP, high tumor uptake (7.05 ± 1.13% ID/g at 30 min) and fast kidney elimination. The results found in this research justify additional dosimetric and clinical studies to establish the sensitivity and specificity of the 99mTc-iFAP.

scholarly journals Fibroblast activation protein targeted near infrared photoimmunotherapy (NIR PIT) overcomes therapeutic resistance in human esophageal cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryoichi Katsube ◽  
Kazuhiro Noma ◽  
Toshiaki Ohara ◽  
Noriyuki Nishiwaki ◽  
Teruki Kobayashi ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Near Infrared ◽  
Fibroblast Activation Protein ◽  
Therapeutic Resistance ◽  
Fibroblast Activation ◽  
Human Esophageal Cancer

AbstractCancer-associated fibroblasts (CAFs) have an important role in the tumor microenvironment. CAFs have the multifunctionality which strongly support cancer progression and the acquisition of therapeutic resistance by cancer cells. Near-infrared photoimmunotherapy (NIR-PIT) is a novel cancer treatment that uses a highly selective monoclonal antibody (mAb)-photosensitizer conjugate. We developed fibroblast activation protein (FAP)-targeted NIR-PIT, in which IR700 was conjugated to a FAP-specific antibody to target CAFs (CAFs-targeted NIR-PIT: CAFs-PIT). Thus, we hypothesized that the control of CAFs could overcome the resistance to conventional chemotherapy in esophageal cancer (EC). In this study, we evaluated whether EC cell acquisition of stronger malignant characteristics and refractoriness to chemoradiotherapy are mediated by CAFs. Next, we assessed whether the resistance could be rescued by eliminating CAF stimulation by CAFs-PIT in vitro and in vivo. Cancer cells acquired chemoradiotherapy resistance via CAF stimulation in vitro and 5-fluorouracil (FU) resistance in CAF-coinoculated tumor models in vivo. CAF stimulation promoted the migration/invasion of cancer cells and a stem-like phenotype in vitro, which were rescued by elimination of CAF stimulation. CAFs-PIT had a highly selective effect on CAFs in vitro. Finally, CAF elimination by CAFs-PIT in vivo demonstrated that the combination of 5-FU and NIR-PIT succeeded in producing 70.9% tumor reduction, while 5-FU alone achieved only 13.3% reduction, suggesting the recovery of 5-FU sensitivity in CAF-rich tumors. In conclusion, CAFs-PIT could overcome therapeutic resistance via CAF elimination. The combined use of novel targeted CAFs-PIT with conventional anticancer treatments can be expected to provide a more effective and sensible treatment strategy.

A novel fibroblast activation protein-targeted near-infrared fluorescent off–on probe for cancer cell detection, in vitro and in vivo imaging

2018 ◽  
Vol 6 (10) ◽  
pp. 1449-1451 ◽  
Author(s):  
Jie Xing ◽  
Qiuyu Gong ◽  
Ruifen Zou ◽  
Zihou Li ◽  
Yuanzhi Xia ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
In Vivo Imaging ◽  
Near Infrared ◽  
Fibroblast Activation Protein ◽  
Cell Detection ◽  
Fibroblast Activation ◽  
Design And Synthesis ◽  
Cancer Cell Detection

Design and synthesis of a novel fibroblast activation protein “off–on” near-infrared fluorescent probe for cell detection, in vitro and in vivo imaging.

scholarly journals Targeting fibroblast activation protein (FAP): Next generation PET radiotracers using squaramide coupled bifunctional DOTA and DATA5m chelators

2020 ◽  
Author(s):  
Euy Sung Moon ◽  
Filipe Elvas ◽  
Gwendolyn Vliegen ◽  
Stef De Lombaerde ◽  
Christel Vangestel ◽  
...  
Keyword(s):  
Animal Studies ◽  
Ex Vivo ◽  
Tumor Stroma ◽  
Fibroblast Activation Protein ◽  
Squaric Acid ◽  
High Accumulation ◽  
Fibroblast Activation ◽  
Pet Radiotracers

Abstract Background Fibroblast activation protein (FAP) is a proline selective serine protease that is overexpressed in tumor stroma and in lesions of many other diseases that are characterized by tissue remodeling. In 2014, a most potent FAP-inhibitor (referred to as UAMC1110) with low nanomolar FAP-affinity and high selectivity toward related enzymes such as prolyl oligopeptidase (PREP) and the dipeptidyl-peptidases (DPPs): DPP4, DPP8/9 and DPP2 were developed. This inhibitor has been adopted recently by other groups to create radiopharmaceuticals by coupling bifunctional chelator-linker systems. Here, we report squaric acid containing bifunctional DATA5m and DOTA chelators relied on UAMC1110. Results The radiopharmaceuticals DOTA.SA.FAPi and DATA5m.SA.FAPi were synthesized, labeled with gallium-68 and further characterized for in vitro stability, inhibitory efficiency, in vivo targeting properties and ex vivo biodistribution. [68Ga]Ga-DOTA.SA.FAPi and [68Ga]Ga-DATA5m.SA.FAPi showed high complexation after already 10 minutes and high stability over a period of 2 h. Affinity to FAP of DOTA.SA.FAPi and its natGa and natLu-labeled derivatives were in low nanomolar range. Comparable results were obtained for DATA5m.SA.FAPi and its natGa analogue. Additionally, all five compounds showed low affinity for the related protease PREP (high µM range). First proof-of-principle in vivo PET-imaging animal studies of the [68Ga]Ga-DOTA.SA.FAPi precursor in a HT-29 human colorectal cancer xenograft mouse model indicated promising results with high accumulation in tumor and low background signal. Ex vivo biodistribution showed high tumor uptake at 60 min post injection with overall low uptake in healthy tissues. Conclusion In this work, novel PET radiotracers targeting fibroblast activation protein (FAP) were synthesized and biochemically investigated. Critical substructures of the novel compounds are a squaramide linker unit derived from the basic motif of squaric acid, DOTA and DATA5m bifunctional chelators and a FAP-targeting moiety. In conclusion, these new FAP-ligands appear promising, both for further research and development as well as for first human application.

scholarly journals Discovery of a novel fibroblast activation protein (FAP) inhibitor, BR103354, with anti-diabetic and anti-steatotic effects

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jae Min Cho ◽  
Eun Hee Yang ◽  
Wenying Quan ◽  
Eun Hye Nam ◽  
Hyae Gyeong Cheon
Keyword(s):  
Blood Glucose ◽  
Protective Role ◽  
Fibroblast Activation Protein ◽  
Protective Effects ◽  
Inhibitory Effects ◽  
Fibroblast Activation ◽  
Pharmacokinetic Properties ◽  
Blood Glucose Concentrations

AbstractFibroblast growth factor (FGF) 21 is a class of hepatokines that plays a protective role against obesity, insulin resistance, and liver damage. Despite this, protective effects of FGF21 in human appear to be minimal, possibly due to its proteolytic cleavage by the fibroblast activation protein (FAP). Here, we presented a novel FAP inhibitor, BR103354, and described its pharmacological activities as a potential therapeutic agent for the treatment of metabolic disorders. BR103354 inhibited FAP with an IC50 value of 14 nM, showing high selectivity against dipeptidyl peptidase (DPP)-related enzymes and prolyl oligopeptidase (PREP). In differentiated 3T3/L1 adipocytes, the addition of FAP diminished hFGF21-induced Glut1 and phosphorylated levels of ERK, which were restored by BR103354. BR103354 exhibited good pharmacokinetic properties as evidenced by oral bioavailability of 48.4% and minimal hERG inhibition. Single co-administration of BR103354 with hFGF21 reduced nonfasting blood glucose concentrations, in association with increased intact form of hFGF21 in ob/ob mice. Additionally, chronic treatment of BR103354 for 4 weeks reduced nonfasting blood glucose concentrations with improved glucose tolerance and with reduced triglyceride (TG) content in liver of ob/ob mice. Consistently, BR103354 improved hepatic steatosis and fibrosis in a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD)-induced non-alcoholic steatohepatitis (NASH) mouse model. FAP inhibitory effects of BR103354 were confirmed in normal cynomolgus monkeys. Together, BR103354 acts as an effective FAP inhibitor in vitro and in vivo, thereby demonstrating its potential application as an anti-diabetic and anti-NASH agent.

CHARACTERIZATION OF A NEW LCAT MUTATION CAUSING FAMILIAL LCAT DEFICIENCY (FLD) AND THE ROLE OF APOE AS A MODIFIER GENE OF THE FLD PHENOTYPE

2009 ◽  
Vol 32 (6S) ◽  
pp. 3
Author(s):  
A Baass ◽  
H Wassef ◽  
M Tremblay ◽  
L Bernier ◽  
R Dufour ◽  
...  
Keyword(s):  
Modifier Gene ◽  
Size Exclusion ◽  
Plasma Lipoproteins ◽  
Lipoprotein Profile ◽  
Exclusion Chromatography ◽  
Low Hdl ◽  
Lcat Deficiency ◽  
Apoe Genotypes

Introduction: LCAT (lecithin:cholesterol acyltransferase ) is an enzyme which plays an essential role in cholesterol esterification and reverse cholesterol transport. Familial LCAT deficiency (FLD) is a disease characterized by a defect in LCAT resulting in extremely low HDL-C, premature corneal opacities, anemia as well as proteinuria and renal failure. Method: We have identified two brothers presenting characteristics of familial LCAT deficiency. We sequenced the LCAT gene, measured the lipid profile as well as the LCAT activity in 15 members of this kindred. We also characterized the plasma lipoproteins by agarose gel electrophoresis and size exclusion chromatography and sequenced several candidate genes related to dysbetalipoproteinemia in this family. Results: We have identified the first French Canadian kindred with familial LCAT deficiency. Two brothers affected by FLD, were homozygous for a novel LCAT mutation. This c.102delG mutation occurs at the codon for His35 causing a frameshift that stops transcription at codon 61 abolishing LCAT enzymatic activity both in vivo and in vitro. It has a dramatic effect on the lipoprotein profile, with an important reduction of HDL-C in both heterozygotes (22%) and homozygotes (88%) and a significant decrease in LDL-C in heterozygotes (35%) as well as homozygotes (58%). Furthermore, the lipoprotein profile differed markedly between the two affected brothers who had different APOE genotypes. We propose that APOE could be an important modifier gene explaining heterogeneity in lipoprotein profiles observed among FLD patients. Our results suggest that a LCAT-/- genotype associated with an APOE ?2 allele could be a novel mechanism leading to dysbetalipoproteinemia.

scholarly journals A Peptide Found in Human Serum, Derived from the C-Terminus of Albumin, Shows Antifungal Activity In Vitro and In Vivo

2020 ◽  
Vol 8 (10) ◽  
pp. 1627
Author(s):  
Tecla Ciociola ◽  
Pier Paolo Zanello ◽  
Tiziana D’Adda ◽  
Serena Galati ◽  
Stefania Conti ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Human Serum ◽  
Fungicidal Activity ◽  
Galleria Mellonella ◽  
Serum Proteins ◽  
Morphological Alterations ◽  
C Terminus ◽  
Different Sources

The growing problem of antimicrobial resistance highlights the need for alternative strategies to combat infections. From this perspective, there is a considerable interest in natural molecules obtained from different sources, which are shown to be active against microorganisms, either alone or in association with conventional drugs. In this paper, peptides with the same sequence of fragments, found in human serum, derived from physiological proteins, were evaluated for their antifungal activity. A 13-residue peptide, representing the 597–609 fragment within the albumin C-terminus, was proved to exert a fungicidal activity in vitro against pathogenic yeasts and a therapeutic effect in vivo in the experimental model of candidal infection in Galleria mellonella. Studies by confocal microscopy and transmission and scanning electron microscopy demonstrated that the peptide penetrates and accumulates in Candida albicans cells, causing gross morphological alterations in cellular structure. These findings add albumin to the group of proteins, which already includes hemoglobin and antibodies, that could give rise to cryptic antimicrobial fragments, and could suggest their role in anti-infective homeostasis. The study of bioactive fragments from serum proteins could open interesting perspectives for the development of new antimicrobial molecules derived by natural sources.

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 In Vitro and In Vivo Activities of a Triterpenoid Saponin Extract (PX-6518) from the Plant Maesa balansae against Visceral Leishmania Species

2004 ◽  
Vol 48 (1) ◽  
pp. 130-136 ◽  
Author(s):  
Louis Maes ◽  
Dirk Vanden Berghe ◽  
Nils Germonprez ◽  
Ludo Quirijnen ◽  
Paul Cos ◽  
...  
Keyword(s):  
Leishmania Donovani ◽  
Human Fibroblasts ◽  
Subcutaneous Administration ◽  
Leishmania Species ◽  
Host Cells ◽  
Triterpenoid Saponin ◽  
Sodium Stibogluconate ◽  
Triterpenoid Saponins

ABSTRACT The in vitro and in vivo activities of a mixture of six oleane triterpene saponins, recovered from the methanolic extract of the leaves of the Vietnamese plant Maesa balansae (PX-6518), were evaluated against drug-sensitive visceral Leishmania strains. The in vitro 50% inhibitory concentration (IC50) against intracellular Leishmania infantum amastigotes was 0.04 μg/ml. The cytotoxic concentrations causing 50% cell death (CC50s) were about 1 μg/ml in murine macrophage host cells and >32 μg/ml in human fibroblasts (MRC-5 cell line). Evaluation in the Leishmania donovani BALB/c mouse model indicated that a single subcutaneous administration of 0.4 mg/kg at 1 day after infection reduced liver amastigote burdens by about 95% in all treated animals. If treatment was delayed until 14 days after infection, a dose of 1.6 mg/kg of body weight was required to maintain the same level of activity. Single 250-mg/kg doses of sodium stibogluconate (Pentostam) 1 and 14 days after infection produced comparable efficacies. A single dose of PX-6518 at 2.5 mg/kg administered 5 days before infection was still 100% effective in preventing liver infection, suggesting a particularly long residual action. Spleen and bone marrow could not be cleared by PX-6518 nor sodium stibogluconate. PX-6518 did not show activity after oral dosing at up to 200 mg/kg for 5 days. This study concludes that triterpenoid saponins from M. balansae show promising in vitro and in vivo antileishmanial potential and can be considered as new lead structures in the search for novel antileishmanial drugs.

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