Niosomal photodynamic therapy as an ex vivo strategy to eradicate malignant cells from tissue

Background: One of the most interesting applications of photodynamic therapy (PDT) is in situ and ex vivo purging of various tissues from malignant cells [1, 2]. In this regard, the self-aggregation tendency and poor bioavailability of common photosensitizers (PS) are important disadvantages, which can be overcome by the niosomal formulation of PSs. This approach improve PS penetration and bioavailability in the tissue in ex vivo studies [3, 4]. The aim of this research is therefore to prepare a niosomal PS formulation, as a third-generation PS, and to analyze (i) ex vivo PDT toxicity for tissue fragment, (ii) in vitro PDT efficiency, and (iii) single-cell morphology after ORN-based PDT. Methods: Blank (BLK) and OR141-loaded niosomes (ORN) were prepared by a reversed-phase evaporation method (Fig. 1) [5]. After ORN fluorescence microscopy imaging, its shape was examined by transmission electron microscopy (TEM). Moreover, the storage stability was analyzed based on ORN's entrapment efficiency during its storage time at room temperature (25°C) or in the freezer (-20°C). The in vitro study was assessed using ORN-based PDT on a human leukemia cell line (HL-60). Briefly, cells were cultured into a 96-well plate overnight and after 1 h incubation with 1 μM ORN were exposed to day-light LED (157 mW/cm2). The single-cell morphology was measured using super-resolution 3D Nanolive microscopy. Finally, the toxicity of this PDT procedure was studied with an ex vivo test and caspase-3 staining of ORN-treated ovarian tissue fragments. Results: Fluorescence imaging (Fig. 2-a,b) shows the detectability of ORNs, and TEM morphology analysis (Fig. 2-c,d) confirmed the successful OR141-encapsulation into niosomes with the formation of an almost spherical shape. ORN shows no significant leakage at -20°C over 30-day storage, and there was about 90% leakage after one month for the ORN stored at 25°C (Fig. 2-e). Ovarian tissue fragments were employed to study ex vivo PDT toxicity (Fig. 3), the results approved that the procedure did not cause unwanted apoptosis on normal tissue (Fig. 4-a,b). On the other, in vitro PDT using 1 μM ORN showed complete eradication of HL-60 cancer cells (Fig. 4-c,d). Moreover, the morphological examination indicated that the cancer cell growth inhibition took place due to permanent membrane shrinking and cytoplasmic degradation after ORN-based PDT (Fig. 4-e,f). Conclusion: Our approach demonstrated to be fluorescence detectable and acceptable storage stability in -20°C. ORN showed a considerable PDT effect on cancer cells, and this promising result shows the potential of ORN application for in situ and ex vivo PDT purging. Further investigations include the ex vivo PDT purging of contaminated fragments to determine the eradication rate of cancer cells. In addition, another niosomal PSs benefit is the ability to be targeted due to the surface functional groups and easy surface modifying with monoclonal antibodies, polymers, or ligands as targeting agents.

Affiliations

UCLouvainSSS/IREC/REPR - Pôle de Recherche en Physiopathologie de la Reproduction

Citations

APA
Chicago
FWB

Moghassemi, S., Dadashzadeh, A., Andrade Amorim, C., & et al. (2021). Niosomal photodynamic therapy as an ex vivo strategy to eradicate malignant cells from tissue. 8th Belgian Symposium on Tissue Engineering (BSTE2021), Louvain-la-Neuve, Belgium. https://hdl.handle.net/2078.5/242720