Hybrid gold nanoparticles coated with organic polymers and antibodies as platforms for cancer theranostics: Investigation of the cytotoxicity mechanisms and feasibility study of radioactive doping

Daems Noami

Promoter

Lucas Stéphane, (FUNDP), stephane.lucas@fundp.ac.be

SCK•CEN Mentor

Aerts An
an.aerts@sckcen.be
+32 14 33 23 90

SCK•CEN Co-mentor

Van Hoecke Karen
karen.van.hoecke@sckcen.be
+32 14 33 82 01

Expert group

Radiobiology

PhD started

2016-10-17

Short project description

Nanoparticles are generally defined as particles with a diameter in the nanometre size range; enabling to directly interface with life at the subcellular scale. In this context, the University of Namur has investigated the great potential of hybrid (organic shell – inorganic core) gold nanoparticles (AuNP) as platforms for cancer theranostics, being able to act both as agents for radiation therapy and diagnostic imaging [1,2]. Indeed, gold particles have emerged as promising radiosensitizers achieving significantly elevated radiation dose upon irradiation, thus increasing the effectiveness of radiation therapy. By decorating the gold nanoparticles through an organic polymer coating strategy with antibodies (mAb) that target the tumor cells, the radiosensitizing effect is focussed to the tumor and not to normal tissues. In addition, targeted gold nanoparticles can serve as imaging contrast agents supporting better tumor localisation and thus improving treatment accuracy.

Preliminary tests at the University of Namur with the AuNP-mAb are encouraging: the nanoparticles are stable and keep the faculty to target the cancer specific antigens in vitro and in vivo. However, the standards associated to the use of nanoparticles in medicine have become increasingly stringent. This imposes us to have a deep understanding of cytotoxicity of nanohybrids on the normal tissue prior to any use.

In addition, to further increase the theranostic applications, the suitability of such AuNP-mAb as a platform for delivery of medical radionuclides to tumor cells has to be tested. In particular, it is interesting to verify the effectiveness of radionuclide-doping of AuNP (leaching, transport and irradiation of healthy tissue have to be prevented) and of dose delivery. Moreover, the potential synergetic effect of the ionizing radiation emitted by the radionuclide and the AuNP radiosensitizing needs to be verified.

[1] Gontard et al 2014, Transmission electron microscopy of unstained hybrid Aunanoparticles capped with PPAA (plasma-poly-allylamine):Structure and electron irradiation effects, Micron 67 (2014) 1–9 [2] Peglow et al 2015, Plasma-vapour-deposition synthesis of Au, Ag and AuAg core-shell nanoparticle on metal oxide semiconductors, 22nd International Symposium on Plasma Chemistry, July 5-10, 2015; Antwerp, Belgium

Objective

Objectives

This research project aims to contribute to the development of gold nanoparticles for cancer diagnostic imaging and radiation therapy.

The following objectives will be addressed:

  • Gain a better understanding of the cytotoxicity mechanisms involved in the interaction of cancer and healthy cells with hybrid AuNP-mAb
  • Acquire knowledge regarding the  production of radionuclide-doped AuNP and their characterization (size distribution, purity, stability)
  • Verify the potential synergy of the ionizing radiation emitted by the radionuclide and the AuNP-mAb radiosensitizing effect

 

Methodology

  • Cytotoxicity

We will use commercially available normal (e.g. kidney, liver, endothelial) and cancer cell lines for incubation with AuNP-mAb. Different biological endpoints will be investigated: cell death, cell proliferation and viability, production of reactive oxygen species and oxidative stress levels, mitochondrial membrane potential, and cell signaling pathways. Techniques that will be applied are flow cytometry, western blot, RT-qPCR, colorimetric assays and fluorescence microscopy. In addition, we will measure gold uptake in the cells by ICP-MS.

  • Doped NP synthesis and characterization

We will benefit from the experience in UNamur to develop at SCK•CEN a technique to obtain AuNP doped with radionuclides of medical interest (e.g. Cu-64, Lu-177, Sm-153) produced by vapour deposition. To minimize operator exposure, initial work will be performed with stable simulants. The obtained nanoparticles will be characterized regarding size (transmission electron microscopy) and purity (gamma spectrometry or X-ray diffraction). In order to verify dose delivery we will assess the extent of DNA double strand breaks using fluorescence microscopy. The stability of the obtained nanoparticles will be assessed by an in vitro leaching study and subsequent analysis of the mobilized radionuclides by HPLC coupled with ICP-MS or gamma spectrometry.

  • Synergetic effect

We will evaluate a potential synergetic effect of the ionizing radiation emitted by the radionuclide and the AuNP-mAb radiosensitizing by assessing the extent of DNA double strand breaks using fluorescence microscopy before and after irradiation for both doped and non-doped AuNP-mAb.