Multiphoton imaging reveals that nanosecond pulsed electric fields collapse tumor and normal vascular perfusion in human glioblastoma xenografts OPEN

Sylvia M. Bardet (1) , Lynn M Carr (2) , Malak M Soueid (2) , Delia Arnaud-Cormos (2, 3) , Philippe Lévêque (2) , Rodney P O 'Connor (1)

1 XLIM - XLIM
2 XLIM-BIO-INGENIERIE - BIO-INGENIERIE
3 IUF - Institut universitaire de France

Despite the biomedical advances of the last century, many cancers including glioblastoma are still resistant to existing therapies leaving patients with poor prognoses. Nanosecond pulsed electric fields (nsPEF) are a promising technology for the treatment of cancer that have thus far been evaluated in vitro and in superficial malignancies. In this paper, we develop a tumor organoid model of glioblastoma and apply intravital multiphoton microscopy to assess their response to nsPEFs. We demonstrate for the first time that a single 10 ns, high voltage electric pulse (35–45 kV/cm), collapses the perfusion of neovasculature, and also alters the diameter of capillaries and larger vessels in normal tissue. These results contribute to the fundamental understanding of nsPEF effects in complex tissue environments, and confirm the potential of nsPEFs to disrupt the microenvironment of solid tumors such as glioblastoma. The brain cancer glioblastoma multiforme (GBM) is incurable and leaves patients with an average survival of approximately 14.6 months after initial diagnosis, despite multimodal treatment with surgery, radiotherapy and chemotherapy 1. Emerging bioelectric therapies such as electrochemotherapy, electrogenetherapy 2,3 and irreversible electroporation 4 have yet to be applied clinically on human cancers of the brain, but preclinical studies have shown the potential of these electroporation-based technologies in neuro-oncology 5,6. Nanosecond pulsed electric fields (nsPEFs) have shown great promise in treating cancer 7,8. At present there have been no investigations of their effects on human glioma or malignancies of the brain. It remains to be determined whether glioblastoma are sensitive to nsPEFs in vivo, and whether it is possible to electrically treat a tumor in the brain without damaging surrounding neurons, glia and vasculature. In vivo models are therefore needed that permit the study of complex tissue reactions to nsPEFs in the intact brain. It is important to first consider the more general issue of whether nsPEFs can be used on highly vascularized tumors like glioma. Thus far, nsPEFs have shown significant promise in the treatment of superficial cancers like melanoma 8–10 , papilloma and squamous cell carcinoma 11. Evidence for the potential of nsPEF to target deep tissue , solid tumors is also encouraging from preclinical animal experiments performed in models of hepatocellular carcinoma 12,13 and breast cancer 14. A gap currently exists between mechanistic in vitro studies on cultured cancer cells and treatment responses observed in animal or human trials of nsPEF therapies. Here we present a method to assess nsPEF effects on a 3D glioblastoma tumor xenograft grown and vascular-ized in the avian chorioallantoic membrane (CAM). This model has previously been used to explore angiogenesis phenomena 15,16 , to assess nanoparticle uptake kinetics 17,18 , and has many other applications in bioengineering 19. We have combined multiphoton imaging with the CAM model using the quail egg and developed a well characterized exposure system to apply nsPEF to this vascularized tumor organoid. The influence of nsPEFs on tumor vasculature was investigated using multiphoton intravital imaging to demonstrate that a single nsPEF pulse was

Mots clés: cancer; Electromagnetic field; nsPEF

Domaines: Imagerie; Biophysique; Biotechnologies; Neurobiologie; Biologie moléculaire; Cancer

Sylvia M. Bardet, Lynn M Carr, Malak M Soueid, Delia Arnaud-Cormos, Philippe Lévêque, et al.. Multiphoton imaging reveals that nanosecond pulsed electric fields collapse tumor and normal vascular perfusion in human glioblastoma xenografts OPEN. Scientific Reports, 2016, ⟨10.1038/srep34443⟩. ⟨hal-01452395⟩