Med Laser  
Photodynamic Therapy for SNU-80 Anaplastic Thyroid Cancer Cells
Seung Hoon Woo, Kun-Woo Kim, Phil-Sang Chung, Sang Joon Lee
Department of Otorhinolaryngology-Head & Neck Surgery, Dankook University, College of Medicine, Cheonan, Korea
Correspondence to: Sang Joon Lee
Received: February 21, 2022; Accepted: March 14, 2022; Published online: March 30, 2022.
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Background and Objectives
Anaplastic thyroid carcinoma (ATC) is a lethal human neoplasm and has a grave prognosis. Photodynamic therapy (PDT) is based on the interaction of a photosensitizer with light at a specific wavelength and induces the destruction of cancer cells. The purpose of this study was to evaluate the effect of PDT with photofrin on SNU-80 anaplastic thyroid cancer cells.
Materials and Methods
After PDT using photofrin, cell viability was measured by the MTT assay. The experiments were done at photofrin concentrations ranging from 1.6 to 3.2 μg/ml. The subcellular localization of photofrin was observed using the ER-TrackerTM and MitoTracker®, Hoechst and propidium iodide (PI) double-stained cells were analyzed to measure the cellular apoptosis and necrosis using a confocal microscope at 4, 8, and 24 hours after laser irradiation. Caspase activation according to the cell death process was measured using the western blot analysis.
Cytotoxicity increased with increasing photofrin concentration in the MTT assay. The photofrin was localized in the cytoplasm and mitochondria inside the SNU-80 cells. The apoptosis and necrosis of cells increased as observed through the confocal microscope, as time after irradiation progressed. The apoptosis and necrosis of the PDT group with a photofrin concentration of 3.2 μg/ml were more than that of the PDT group with a photofrin concentration of 1.6 μg/ml in the Hoechst and PI double staining. The expression of caspase-3, 9, and poly (adp-ribose) polymerases (PARP) was detected by western blot analysis, indicating that photoprin-PDT showed cytotoxicity to anaplastic thyroid cancer cells in a dose-dependent pattern.
Photofrin-PDT led to the in vitro cell death of SNU-80 cells through mitochondria-mediated apoptosis. PDT could thus be used as a part of multimodal treatment for ATC.

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