Enhancement of photodynamic tumor therapy effectiveness by electroporation in vitro

Jūratė Labanauskienė, Saulius Šatkauskas¹, Vida Kirvelienė², Mindaugas Venslauskas¹, Vydmantas Atkočius, Janina Didžiapetrienė

Scientific Research Center, Institute of Oncology, Vilnius University, ¹Department of Biology, Vytautas Magnus University, ²Department of Biochemistry and Biophysics, Vilnius University, Lithuania

Key words: electroporation; photodynamic tumor therapy; chlorin e6; aluminum phthalocyanine tetrasulfonate.

Summary. The aim of our study was to determine if electroporation could improve the efficacy of photodynamic tumor therapy. A disadvantage of photodynamic therapy is a slow and in some cases insufficient accumulation of photosensitizer in tumor tissue, which could restrict the achievement of an efficient dose. Under the action of electric pulses, cells undergo membrane electroporation, which results in an increased permeability to various exogenous molecules. In this study, murine hepatoma MH22A cells were exposed to light in vitro in the presence of a photosensitizer, either chlorin e6 or aluminum phthalocyanine tetrasulfonate, following electroporation. Accumulation of the photosensitizers was registered by fluorescence microscopy. Cell viability was determined by the MTT assay. Our results demonstrate that electroporation improves an access of chlorin e6 and aluminum phthalocyanine tetrasulfonate to MH22A cells. Electroporation in combination with photosensitization significantly reduces viability of the treated cells even at low doses of photosensitizers.

Correspondence to J. Labanauskienė, Scientific Research Center, Institute of Oncology, Vilnius University, Baublio 3B, 08660 Vilnius, Lithuania. E-mail: labajura@gmail.com

Received 17 November 2008, accepted 4 May 2009