@article{doi:10.1021/acs.bioconjchem.7b00374,

title = {Nanofitin as a New Molecular-Imaging Agent for the Diagnosis of Epidermal Growth Factor Receptor Over-Expressing Tumors},

author = {Marine Goux and Guillaume Becker and Harmony Gorré and Sylvestre Dammicco and Ariane Desselle and Dominique Egrise and Natacha Leroi and François Lallemand and Mohamed Ali Bahri and Gilles Doumont and Alain Plenevaux and Mathieu Cinier and André Luxen},

url = {https://doi.org/10.1021/acs.bioconjchem.7b00374},

doi = {10.1021/acs.bioconjchem.7b00374},

year  = {2017},

date = {2017-01-01},

journal = {Bioconjugate Chemistry},

volume = {28},

number = {9},

pages = {2361-2371},

abstract = {Epidermal growth-factor receptor (EGFR) is involved in cell growth and proliferation and is over-expressed in malignant tissues. Although anti-EGFR-based immunotherapy became a standard of care for patients with EGFR-positive tumors, this strategy of addressing cancer tumors by targeting EGFR with monoclonal antibodies is less-developed for patient diagnostic and monitoring. Indeed, antibodies exhibit a slow blood clearance, which is detrimental for positron emission tomography (PET) imaging. New molecular probes are proposed to overcome such limitations for patient monitoring, making use of low-molecular-weight protein scaffolds as alternatives to antibodies, such as Nanofitins with better pharmacokinetic profiles. Anti-EGFR Nanofitin B10 was reformatted by genetic engineering to exhibit a unique cysteine moiety at its C-terminus, which allows the development of a fast and site-specific radiolabeling procedure with 18F–4-fluorobenzamido-N-ethylamino-maleimide (18F–FBEM). The in vivo tumor targeting and imaging profile of the anti-EGFR Cys–B10 Nanofitin was investigated in a double-tumor xenograft model by static small-animal PET at 2 h after tail-vein injection of the radiolabeled Nanofitin 18F–FBEM–Cys–B10. The image showed that the EGFR-positive tumor (A431) is clearly delineated in comparison to the EGFR-negative tumor (H520) with a significant tumor-to-background contrast. 18F–FBEM–Cys–B10 demonstrated a significantly higher retention in A431 tumors than in H520 tumors at 2.5 h post-injection with a A431-to-H520 uptake ratio of 2.53 ± 0.18 and a tumor-to-blood ratio of 4.55 ± 0.63. This study provides the first report of Nanofitin scaffold used as a targeted PET radiotracer for in vivo imaging of EGFR-positive tumor, with the anti-EGFR B10 Nanofitin used as proof-of-concept. The fast generation of specific Nanofitins via a fully in vitro selection process, together with the excellent imaging features of the Nanofitin scaffold, could facilitate the development of valuable PET-based companion diagnostics.},

note = {PMID: 28825794},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{DAMMICCO201733,

title = {Regiospecific radiolabelling of Nanofitin on Ni magnetic beads with [18F]FBEM and in vivo PET studies},

author = {Sylvestre Dammicco and Marine Goux and Christian Lemaire and Guillaume Becker and Mohamed Ali Bahri and Alain Plenevaux and Mathieu Cinier and André Luxen},

url = {https://www.sciencedirect.com/science/article/pii/S0969805116303304},

doi = {https://doi.org/10.1016/j.nucmedbio.2017.04.006},

issn = {0969-8051},

year  = {2017},

date = {2017-01-01},

journal = {Nuclear Medicine and Biology},

volume = {51},

pages = {33-39},

abstract = {Introduction 

Nanofitins are low molecular weight, single chain and cysteine-free protein scaffolds able to selectively bind a defined biological target. They derive from Sac7d bacterial protein family and are highly stable over a wide range of pH (0–13) and temperature (Tm ~80°C). Their extreme stability, low cost of production and high tolerability for chemical coupling make Nanofitins a very interesting alternative to antibodies and their fragments. Here, a hexahistidine tagged model Nanofitin (H4) directed against hen egg white lysozyme was radiolabelled and injected in mice to provide a baseline biodistribution and pharmacokinetic profiles to support future Nanofitin development programs. 

Method 

A single cysteine residue has been genetically inserted in a model Nanofitin and its regioselective radiolabelling has been performed with 4-[18F]fluorobenzamido-N-ethylamino-maleimide ([18F]FBEM). The synthesis of [18F]FBEM has been completely implemented on a radiosynthesis unit (FastLab) including HPLC purification and formulation. Coupling with the [18F]FBEM has been achieved on a solid support (Ni magnetic beads) allowing rapid purification at room temperature without organic solvent. PET-MRI studies on C57BL/6 mice were conducted after injection of [18F]FBEM-Cys-H4 in order to access the biodistribution of this Nanofitin model. 

Results Radiochemical yield (decay corrected) of 54±7% (n=4) was obtained after optimization for coupling the [18F]FBEM to Nanofitin. Pharmacokinetics results of [18F]FBEM-Cys-H4 revealed a fast clearance through the liver and the kidneys. 

Conclusion 

An efficient new method on Ni magnetic beads was developed to radiolabelled his-tagged biomolecules with [18F]FBEM. This procedure was applied on a Nanofitin model Cys-H4 and biodistribution kinetic studies were achieved to evaluate the potential use of Nanofitin for diagnostic imaging. Fast clearance indicates that Nanofitins represent very interesting tools for diagnostic imaging. Image 1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}