Unraveling Microviscosity Changes Induced in Cancer Cells by Photodynamic Therapy with Targeted Genetically Encoded Photosensitizer.

Background: Despite the fundamental importance of cell membrane microviscosity, changes in this biophysical parameter of membranes during photodynamic therapy (PDT) have not been fully understood.

Methods: In this work, changes in the microviscosity of membranes of live HeLa Kyoto tumor cells were studied during PDT with KillerRed, a genetically encoded photosensitizer, in different cellular localizations. Membrane microviscosity was visualized using fluorescence lifetime imaging microscopy (FLIM) with a viscosity-sensitive BODIPY2 rotor.

Photodynamic therapy with Photoditazine increases microviscosity of cancer cells membrane in cellulo and in vivo.

Photodynamic therapy (PDT) is a minimally invasive method for cancer treatment, one of the effects of which is the oxidation of membrane lipids. However, changes in biophysical properties of lipid membranes during PDT have been poorly explored. In this work, we investigated the effects of PDT on membrane microviscosity in cancer cells in the culture and tumor xenografts.