Enhancing the photodynamic effect of hypericin in human bladder transitional cell carcinoma spheroids by the use of the oxygen carrier, perfluorodecalin

Abstract

Abstract. In the present study, we evaluated the possibility of enhancing the photodynamic effect of hypericin in transitional cell carcinoma (TCC) spheroids by the use of the oxygen carrier, perfluorodecalin. Following incubation with hypericin, RT-112 TCC spheroids were irradiated in the presence or absence of perfluorodecalin, at light doses of 7 J/cm 2 or 28 J/ cm 2 , delivered at a fluence rate of 15 mW/cm 2 . The photodynamic therapy (PDT) efficacy was evaluated and apoptotic cells were visualized. The results show that, in the absence of perfluorodecalin, spheroidal TCC cells are inadequately sensitive to hypericin PDT. As was shown by fluorescence microscopy, this lack of activity was not due to insufficient photoactive concentrations of hypericin reaching the inner parts of the spheroids. Conversely, enhanced oxygenation of spheroids by perfluorodecalin led to a dramatic enhancement of hypericin PDT efficacy. The detection of nuclear shrinkage or fragmentation with DAPI staining and the assessment of cell morphology by light microscopy indicated that apoptosis was the most prominent response of spheroids to hypericin PDT in the presence of perfluorodecalin. In conclusion, the results of this study suggest that perfluorocarbons, such as perfluorodecalin, are useful in enhancing the oxygenation of tumor tissue, resulting in highly efficient hypericin PDT. Since hypericin becomes concentrated specifically in human bladder urothelial carcinoma lesions and the bladder is very well suited to instillation with a perfluorocarbon, combining the techniques looks very promising for an efficient and selective whole bladder wall photodynamic antitumoral treatment in a urological clinical setting.

Biodistribution and photodynamic effects of polyvinylpyrrolidone-hypericin using multicellular spheroids composed of normal human urothelial and T24 transitional cell carcinoma cells

“…One technique used normobaric oxygen that was simply bubbled through the solution that surrounded the spheroids, whereas the other approach used a biocompatible perfluorocarbon as oxygen carrier to hyperoxygenate the biological surrounding. 23,24 Because both modalities are rather easy to apply to the bladder cavity, PDT with PVP-hypericin combined with either of the techniques looks very promising for an efficient and selective whole-bladderwall photodynamic antitumoral treatment in a urological clinical setting. Obviously, further in vivo experiments are required to fully evaluate the potential of PVP-hypericin as a phototherapeutic, focusing on the combination of the compound with methods that enhance the oxygenation of the urothelium.…”

Photodynamic Therapy of Nonmelanoma Skin Cancer with Topical Hypericum perforatum Extract—A Pilot Study

“…Due to its selective accumulation in bladder carcinoma lesions, the substance is now used as a fluorescent diagnostic tool for superficial bladder cancer (28). Its utilization for PDT of superficial bladder cancer underwent intense investigation (29). To date, there has been only one report in the literature regarding the treatment of nonmelanoma skin cancer with hypericin.…”

Photodynamic diagnostics of bladder tumors

“…Further, fluorescent substances have been developed. There are preliminary investigations of hypericin derived from Hypericum perforatum (St. John's wort), that have recently suggested a phototoxic effect on UC [6,8]. The 5-ALA ester hexaminolevulinate acid (HAL) has been shown to provide intense levels of photodynamic activity and has been suggested as a feasible aid in cytopathologic detection of UC [3,9,10,11].…”