Efficacy of Chlorin e6-Mediated Sono-Photodynamic Therapy on 4T1 Cells

Abstract Purpose: The present study aims to investigate the antitumor effect and possible mechanisms of chlorin e6 (Ce6)-mediated sono-photodynamic therapy (Ce6-SPDT) on murine 4T1 mammary cancer cells in vitro. Materials: Cellular uptake and intracellular distribution of Ce6 in 4T1 cells were detected by flow cytometry and confocal microscope. Cells after loading with 1 μg/mL Ce6 were exposed to ultrasound at 1.0 MHz for up to 1 minute with an intensity of 0.36 W/cm2 and laser light with total radiation dose of 1.2 J/cm2. Cell viability and clonogenicity were determined by MTT assay and colony formation assay. Apoptosis was analyzed by DAPI staining, Western blots were used to detect the activity of Caspase-3. DNA damage, mitochondrial membrane potential (MMP), and intracellular reactive oxygen species (ROS) of 4T1 cells were also evaluated by flow cytometry. FD500 was employed to detect changes of membrane permeability after ultrasound. Results: Ce6 rapidly entered 4T1 cells within 4 hours after it has ...