Ablation of near infra-red stable transfected prostate cancer cell lines by C-CPE gold-nanoparticle mediated laser intervention
17 February 2020 (online)
Introduction Claudin (CLDN) genes are deregulated in prostate cancer. Accordingly, targeting of CLDNs has been evaluated to establish novel therapeutic approaches. C-terminal domain of Clostridium perfringens enterotoxin (C-CPE) has a high affinity to bind to several CLDNs and thus recombinant C-CPE binders conjugated to gold nanoparticles (AuNPs) have been used to target cancer cells specifically. Inoculation of cancer cells is routinely used to generate in vivo models to understand the pathogenesis of prostate cancer and to develop novel therapeutic approaches. However, detailed characterization of cancer spreading and early tumour development is limited as conventional cell lines do not allow advanced deep tissue imaging. Herein, we established 2 canine prostate carcinoma cell lines, stably expressing fluorescent proteins in near infra-red (NIR) spectrum allowing perspective deep tissue imaging.
Methods Expression of NIR marker protein as well as CLDN3, -4 and -7 was confirmed by flow cytometry, qPCR and immunofluorescence. C-CPE binding to CLDNs was investigated through immunostaining. Cancer cells ablation was demonstrated in an in vitro setting using a combination of gold nanoparticles mediated laser perforation (GNOME-LP) technique and C-CPE-AuNPs.
Results C-CPE binding to native and NIR transfected cancer cells verified the capability of C-CPE binding to specifically target the CLDN receptors. Application of GNOME-LP reduces tumor cell viability to less than 10% depending on cell line.
Discussion The established cell lines and the verified proof of concept in vitro provide the basis for perspective xenograft in vivo studies. The introduced red fluorescence enables deep tissue imaging in living animals and therefore detailed characterization of tumor growth and subsequently possible tumor ablation through C-CPE-AuNPs treatment.