Abstract 1315: Real-time imaging of nuclear-cytoplasmic dynamics in UV light killing of cancer cells expressing fluorescent proteins

Abstract

Abstract Our laboratory pioneered dual-color cancer cells, in which red fluorescent protein (RFP) is expressed in the cytoplasm and green fluorescent protein (GFP) in the nucleus (Cancer Research 64, 4251-4256, 2004; Nature Protocols 1, 928-935, 2006). Total cellular dynamics can be visualized in the living dual-color cells in real time. In this study, we investigated the cancer-cell-killing efficacy of UV light using the dual-color cancer cells. For UV irradiation experiments, a Benchtop 3UV transilluminator, which emits UVC with an emission peak at 254 nm; UVB with an emission peak at 302 nm; and UVA with an emission peak at 365 nm; was used. After exposure to various doses of UVA, UVB, or UVC, apoptotic, necrotic and viable cells were quantitated under fluorescence microscopy using dual-color 143B human osteosarcoma cells (143B). UV-induced cancer cell death was wave-length and dose dependent. After UVA exposure, most cells were viable even if the UV dose was increased up to 200 J/m2. In the UVB group, cell death began to appear when irradiated at 50 J/m2. For UVC, the rate of cell killing was proportional to increased UVC irradiation. 25 J/m2 UVC irradiation killed over 40% of the 143B dual-color cells. However, the rate of cell killing plateaued at 100 J/m2. We also tested 50J/m2 UVC and 100J/m2 of UVB on four types of dual-color cancer cell lines. UV-induced cancer cell death varied among the cell lines. Cell death began about 4 hours after irradiation and continued until 10 hours after irradiation. Real-time movies were made of cells undergoing UV-induced cell death. Most cells died via apoptosis and only a small portion of them died via necrosis. We will develop UV irradiation for treatment of fluorescent-protein-expressing minimal residual cancer remaining after resection. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1315.