Therapeutic and Radiosensitizing Effects of Armillaridin on Human Esophageal Cancer Cells

Background . Armillaridin (AM) is isolated from Armillaria mellea . We examined the anticancer activity and radiosensitizing effect on human esophageal cancer cells. Methods . Human squamous cell carcinoma (CE81T/VGH and TE-2) and adenocarcinoma (BE-3 and SKGT-4) cell lines were cultured. The MTT assay was used for cell viability. The cell cycle was analyzed using propidium iodide staining. Mitochondrial transmembrane potential was measured by DiOC 6 (3) staining. The colony formation assay was performed for estimation of the radiation surviving fraction. Human CE81T/VGH xenografts were established for evaluation of therapeutic activity in vivo . Results . AM inhibited the viability of four human esophageal cancer cell lines with an estimated concentration of 50% inhibition (IC 50 ) which was 3.4–6.9  μ M. AM induced a hypoploid cell population and morphological alterations typical of apoptosis in cells. This apoptosis induction was accompanied by a reduction of mitochondrial transmembrane potential. AM accumulated cell cycle at G 2 /M phase and enhanced the radiosensitivity in CE81T/VGH cells. In vivo , AM inhibited the growth of CE81T/VGH xenografts without significant impact on body weight and white blood cell counts. Conclusion . Armillaridin could inhibit growth and enhance radiosensitivity of human esophageal cancer cells. There might be potential to integrate AM with radiotherapy for esophageal cancer treatment.