VIS UALIZA TI O N O F N A N O M E D I C I N E S IN
THERA PE UTI C T R EA T M E N T S W IT H N E WT O N 7 . 0AUTHORS
Laurence Poul1; Julie Devalliere¹; Marion Paolini2; Audrey Darmon1; Maxime
Bergère1; Océane Jibault1; Francis Mpambani1; Matthieu Germain1.
1
Nanobiotix, Paris, France2
Koch Institute for Integrative Cancer Research, MIT, Cambridge, USA

INTRODUCTION
Gastric cancer (GC) is one of the leading causes of cancer-related deathworldwide. Recent advances identified reliable predictive biomarkers such as
human epidermal growth factor receptor (HER2), thus introducing moleculartargeted drug therapy. GC’s HER2-positive, when amplified or over expressed,
play an important role in the development and progression of certain
aggressive types of breast cancer. Trastuzumab, an anti-HER2 mAb(monoclonal antibody), has been used previously as a targeted therapy for
HER2-positive GC. It induces an immune-mediated response that causesinternalization and downregulation of HER2 and yields excellent treatment
outcomes. Radioimmunotherapy (RIT) is a targeted radioisotope treatment
method that uses an antibody as a carrier of therapeutic radioisotopes. The
selective targeting of radioisotopes to the tumor using a radiolabeled cancerspecific antibody enables the delivery of a high dose of radiation directly tocancer cells while minimizing the exposure of normal cells. 211At is ofparticular interest because it emits highly cytotoxic α -particles that can kill atarget cell, making it one of the most potent cell-killing agents available.
Astatine-211 is therefore particularly suited to the targeted killing ofdisseminated or micrometastatic solid tumors that are usually resistant.

OBJECTIVE
This study designed a liposomal nanoprimer with specific physico-chemical
attributes chosen to favor its liver accumulation. This nanoprimer occupies
transiently and physically the liver cells involved in the clearance ofnanomedicines, Kupffer cells and Liver Sinusoidal Endothelial Cells (LSEC), toredefine the nanomedicines bioavailability. Furthermore, since abioavailability increase alone may not be sufficient to improve the treatment’s
benefit/risk ratio (potential new toxicity, target tissue diffusion or cell uptake),the impact of liposomal nanoprimer on a given nanomedicine efficacy wasevaluated.

MATERIAL & METHODS
Liposomes synthesis.
Liposomal nanoprimers were composed of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(succinyl) (sodium salt) (SPE) and Chol (50:50,molar ratio). They were synthetized using the thin-film hydration techniqueand the concentration of phospholipid was determined by colorimetricassay.
Nanoprimer biodistribution study.
All in vivo manipulations were performed on adult female mice (NMRIFox1nu/Foxn1nu) (Janvier, France) at the Ecole Nationale Veterinaire d’Alfort(Maisons-Alfort, France). For Newton mini biodistribution study, liposomal
nanoprimer were loaded with 20nm fluorescent polystyrene nanoparticles.
This liposomal nanoprimer was synthetized as described above but
including fluorescent polystyrene nanoparticles in the hydration medium.
After extrusion process, non-encapsulated polystyrene nanoparticles wereremoved from loaded liposomal nanoprimer by size exclusion
chromatography on a sephacryl S-1000 column. For Newton mini follow up,fluorescently labelled nanoprimer injections (20mM; 10mL/kg) wereperformed in the tail vein of anesthetized mice (Isofurane (1–5%), oxygen (1–2L/min)). Then animals were immediately placed in dorsal recumbency andimaged with Newton mini (Vilber Lourmat) to perform 2D fluorescentacquisitions (ex: 745nm; em: 820nm) starting 1min after nanoprimer
injection, every minute during 1h on whole body. The fluorescenceacquisitions were analyzed with the software Newton FT500.

Figure 1.
T0 + 10min

T0 + 20min

T0 + 30min

High Level
Epi-fluorescence (a. u.)particules alone

Figure 2.

T0 + 1min

T0 + 5min

T0 + 10min

T0 + 20min

T0 + 30min

CONCLUSION
This study establishes a new strategy to redefine benefit / risk ratio oftherapeutic agents by priming the body to receive the treatment, asdemonstrated above. The imaging performed with Newton mini (VilberLourmat, France) enlightens the ability of the liposomal nanoprimer toincrease nanoparticles blood circulation, and also demonstrates theabilities of the Newton mini in imaging nanoparticles and theirdistribution pattern.

T0 + 1H

Injected at 2 ml/kg

T0 + 5min

Low Level

Fluorescent nano‐Figure 2. Impact of nanoprimer on nanomedicine model
bioavailability. Nanoprimer increases nanoparticles systemic
bioavailability.
PEG-coated polystyrene (PS) nanoparticles were used as
nanomedicine model. 200 nm fluorescent PEG-coated PS
nanoparticles were intravenously injected in mice alone, or 10 min
after intravenous injection of the liposomal nanoprimer. Immediately
after PS nanoparticles injections, whole body fluorescenceacquisitions were performed on mice for 1 H, using an in vivo imaging
device, Newton mini (Vilber Lourmat, France). An increased
bioavailability of PS nanoparticles is observed for at least 1 H whenadministered in the presence of the nanoprimer. This enhanced blood
availability is correlated with a lower accumulation of the PS
nanoparticles in the liver and the spleen and without a noticeable
accumulation in other organs.

10min before

Figure 1. Nanoprimer accumulates specifically and drastically in theliver after intravenous injection.
A 110mM fluorescent labelled nanoprimer solution was intravenously
injected in the tail vein of mice at 2ml/kg. Then, fluorescenceacquisitions were performed on whole mice during 1 h using Newton
Mini (Vilber Lourmat, France).
Fig1. shows preferential accumulation of the liposomal nanoprimer inthe liver within the 10 min following intravenous injection in mice, with
only a small fraction remaining in the blood. Thus suggesting that atime schedule of 10 min could be used between the injections ofnanoprimer and nanomedicine.

+ nanoprimer

RESULTS

Fluorescent nanoprimer

T0 + 1min

Low Level

High Level
Epi-fluorescence (a. u.)

T0 + 1H