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 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.

scholarly journals The MEMIC: An ex vivo system to model the complexity of the tumor microenvironment

2021 ◽  
Author(s):  
Libuše Janská ◽  
Libi Anandi ◽  
Nell C. Kirchberger ◽  
Zoran S. Marinkovic ◽  
Logan T. Schachtner ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Ex Vivo ◽  
Tumor Stroma ◽  
Stem Cell Differentiation ◽  
Blood Stream ◽  
Direct Access ◽  
Ex Vivo Model

There is an urgent need for accurate, scalable, and cost-efficient experimental systems to model the complexity of the tumor microenvironment. Here, we detail how to fabricate and use the Metabolic Microenvironment Chamber (MEMIC) – a 3D-printed ex vivo model of intratumoral heterogeneity. A major driver of the cellular and molecular diversity in tumors is the accessibility to the blood stream that provides key resources such as oxygen and nutrients. While some tumor cells have direct access to these resources, many others must survive under progressively more ischemic environments as they reside further from the vasculature. The MEMIC is designed to simulate the differential access to nutrients and allows co-culturing different cell types, such as tumor and immune cells. This system is optimized for live imaging and other microscopy-based approaches, and it is a powerful tool to study tumor features such as the effect of nutrient scarcity on tumor-stroma interactions. Due to its adaptable design and full experimental control, the MEMIC provide insights into the tumor microenvironment that would be difficult to obtain via other methods. As a proof of principle, we show that cells sense gradual changes in metabolite concentration resulting in multicellular spatial patterns of signal activation and cell proliferation. To illustrate the ease of studying cell-cell interactions in the MEMIC, we show that ischemic macrophages reduce epithelial features in neighboring tumor cells. We propose the MEMIC as a complement to standard in vitro and in vivo experiments, diversifying the tools available to accurately model, perturb, and monitor the tumor microenvironment, as well as to understand how extracellular metabolites affect other processes such as wound healing and stem cell differentiation.

In Situ Gels of Acylovir Nanoemulsions For Improved Delivery to The Eye

2021 ◽  
Vol 11 ◽  
Author(s):  
Manza M. Priyanka ◽  
Shinde A. Ujwala ◽  
Sheth M. Kalyani ◽  
Namita Desai
Keyword(s):  
Animal Studies ◽  
Ex Vivo ◽  
In Vitro Release ◽  
Corneal Stroma ◽  
Class Iii ◽  
Ophthalmic Delivery ◽  
Histopathological Studies

Background: Acyclovir, BCS Class III drug is commercially available as 3 % w/w eye ointment for multiple applications. Acyclovir nanoemulsions can be proposed to reduce dose because of improved permeation characteristics. Further, the development of in situ ophthalmic gels can be advantageous to reduce the number of applications due to increased mucoadhesion and sustaining effect. Objective: The purpose of this study was the development and evaluation of nanoemulsions based in situ gels of Acyclovir (1% w/w) as potential ophthalmic delivery systems. Methods: Nanoemulsions of Acyclovir were developed by Phase Inversion Temperature method using Capmul MCM, stearyl amine and Kolliphor RH 40 as liquid lipid, charge inducer and surfactant, respectively selected on the basis of Acyclovir solubility studies in the oil phase and emulsification ability of surfactants. These nanoemulsions were further developed into in situ ophthalmic gels using gellan gum and Methocel K4M. Results: The developed gels showed a sustained effect in vitro release studies and improved goat corneal permeation in ex vivo studies when compared to marketed ointment. HET-CAM studies concluded the absence of irritation potential, while in vivo irritation study in Wistar rats showed the absence of erythema and swelling of eyes after visual inspection for 72 hours. Histopathological studies on isolated rat corneas showed no abnormalities in anterior corneal epithelium and corneal stroma without any epithelial hyperplasia. Acyclovir nanoemulsions based in situ ophthalmic gel showed increased corneal deposition and permeation in rat eyes. Conclusion: The improved potential of developed ophthalmic gels was proven due to the reduced frequency of application compared to the marketed ointment in animal studies.

Evaluation and Prevalidation of an Immunotoxicity Test Based on Human Whole-blood Cytokine Release

2002 ◽  
Vol 30 (6) ◽  
pp. 581-595 ◽  
Author(s):  
Ingrid Langezaal ◽  
Sebastian Hoffmann ◽  
Thomas Hartung ◽  
Sandra Coecke
Keyword(s):  
Immune System ◽  
Whole Blood ◽  
Animal Studies ◽  
Ex Vivo ◽  
Interleukin 4 ◽  
Cytokine Release ◽  
Fourfold Increase ◽  
Ic50 Values

Immunotoxicology is a relatively new field in toxicology, and is one of emerging importance, because immunotoxicity appears to contribute to the development of cancer, autoimmune disorders, allergies and other diseases. At present, there is a lack of human cell-based immunotoxicity assays for predicting the toxicity of xenobiotics toward the immune system in a simple, fast, economical and reliable way. Existing immunotoxicity tests are mainly performed in animals, although species differences favour human-based testing. Whole-blood cytokine release models have attracted increasing interest, and are broadly used for pharmacological in vitro and ex vivo studies, as well as for pyrogenicity testing. We have adapted those methods for immunotoxicity testing, to permit the potency testing of immunostimulants and immunosuppressants. Following stimulation with a lipopolysaccharide or staphylococcal enterotoxin B, monocytes and lymphocytes release interleukin-1β and interleukin-4, respectively. Thirty-one pharmaceutical compounds, with known effects on the immune system, were used to optimise and standardise the method, by analysing their effects on cytokine release. The in vitro results were expressed as IC50 values for immunosuppression, and SC4 (fourfold increase) values for immunostimulation, and compared with therapeutic serum concentrations of the compounds in patients, and in vivo LD50 values from animal studies. The in vitro results correlated well with the in vivo data, so the test appears to reflect immunomodulation. Results were reproducible (CV = 20 ± 5%), and the method could be transferred to another laboratory (r2 = 0.99). We therefore propose this method for further validation and for use in immunotoxicity testing strategies.

scholarly journals Oral Insulin Delivery Using Poly (Styrene Co-Maleic Acid) Micelles in a Diabetic Mouse Model

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1026
Author(s):  
Fatemah Bahman ◽  
Sebastien Taurin ◽  
Diab Altayeb ◽  
Safa Taha ◽  
Moiz Bakhiet ◽  
...  
Keyword(s):  
Mouse Model ◽  
Maleic Acid ◽  
Oral Delivery ◽  
Animal Studies ◽  
Ex Vivo ◽  
Insulin Delivery ◽  
Diabetic Mouse ◽  
Oral Insulin

The oral delivery of insulin is a convenient and safe physiological route of administration for management of diabetes mellitus. In this study, we developed a poly-(styrene-co-maleic acid) (SMA) micellar system for oral insulin delivery to overcome the rapid degradation of insulin in the stomach, improve its absorption in the intestine, and provide a physiologically-relevant method of insulin to reach portal circulation. The insulin was encapsulated into SMA micelles in a pH-dependent process. The charge and size of the nanoparticles were determined by dynamic light scattering. The insulin loading of the nanoparticles was measured by HPLC. The transport of the SMA-insulin through biological membranes was assessed in vitro using Caco-2 cells, ex vivo rat intestinal section, and in vivo in a streptozotocin-induced diabetes mouse model. SMA-insulin micelles were negatively charged and had a mean diameter of 179.7 nm. SMA-insulin efficiently stimulated glucose uptake in HepG-2 hepatic cells and was transported across the Caco-2 epithelial cells in vitro by 46% and ex vivo across intestinal epithelium by 22%. The animal studies demonstrated that orally-administered SMA-insulin can produce a hypoglycemic effect up to 3 h after administration of one dose. Overall, our results indicate that SMA micelles are capable of the oral delivery of bioactive compounds like insulin and can be effective tools in the management of diabetes.

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 Mechanical strength and hydrostatic testing of VIVO adhesive in sutureless microsurgical anastomoses: an ex vivo study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marius Heitzer ◽  
Julia Brockhaus ◽  
Kristian Kniha ◽  
Felix Merkord ◽  
Florian Peters ◽  
...  
Keyword(s):  
Animal Studies ◽  
Ex Vivo ◽  
Coronary Vessels ◽  
In Vitro Study ◽  
The Novel ◽  
Ex Vivo Model ◽  
Interrupted Suture ◽  
Tensile Forces

AbstractConventional anastomoses with interrupted sutures are challenging and inevitably associated with trauma to the vessel walls. The goal of this study was to evaluate a novel alternative adhesive-based suture-free anastomosis technique that uses an intraluminal stent. Overall, 120 porcine coronary vessels were analyzed in an ex vivo model and were examined for their mechanical (n = 20 per cohort) and hydrostatic strength (n = 20 per cohort). Anastomoses were made using the novel VIVO adhesive with an additional intraluminal nitinol stent and was compared to interrupted suture anastomosis and to native vessels. Sutureless anastomoses withstood pressures 299 ± 4.47 [mmHg] comparable to native vessels. They were performed significantly faster 553.8 ± 82.44 [sec] (p ≤ 0.001) and withstood significantly higher pressures (p ≤ 0.001) than sutured anastomoses. We demonstrate that the adhesive-based anastomosis can also resist unphysiologically high longitudinal tensile forces with a mean of 1.33 [N]. Within the limitations of an in vitro study adhesive-based suture-free anastomosis technique has the biomechanical potential to offer a seamless alternative to sutured anastomosis because of its stability, and faster handling. In vivo animal studies are needed to validate outcomes and confirm safety.

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.

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