Putative progenitor/stem cells isolated from human oral mucosa are resistant to ionizing radiation

Abstract

Oral mucositis is a common complication of radiotherapy and/or chemotherapy in patients with squamous cell carcinoma of the head and neck. Ionizing radiation causes loss of stem cells having renewal capacity in the basal layer of the mucosa, which is the beginning of radiation mucositis [ [1] Sonis S.T. The pathobiology of mucositis. Nat Rev Cancer. 2004; 4: 277-284 Crossref PubMed Scopus (841) Google Scholar ]. Embryonic or mesenchymal stem cells have been reported to resist oxidative stress from noxious stimuli such as radiation [ 2 Saretzki G. Armstrong L. Leake A. Lako M. von Zglinicki T. Stress defense in murine embryonic stem cells is superior to that of various differentiated murine cells. Stem Cells. 2004; 22: 962-971 Crossref PubMed Scopus (227) Google Scholar , 3 Chen M.F. Lin C.T. Chen W.C. Yang C.T. Chen C.C. Liao S.K. et al. The sensitivity of human mesenchymal stem cells to ionizing radiation. Int J Radiat Oncol Biol Phys. 2006; 66: 244-253 Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar ]. However, the radiation resistance of oral mucosal stem cells is still unknown. In this study, we attempted to separate stem cell-rich subpopulation from human oral mucosa by differential adhesion to collagen type IV, the method being used to isolate epidermal stem cells [ [4] Kim D.S. Cho H.J. Choi H.R. Kwon S.B. Park K.C. Isolation of human epidermal stem cells by adherence and the reconstruction of skin equivalents. Cell Mol Life Sci. 2004; 61: 2774-2781 Crossref PubMed Scopus (115) Google Scholar ]. Radiation sensitivity of the stem cell-rich and stem cell-poor subpopulations was compared.