CD200: Association with cancer stem cell features and response to chemoradiation in head and neck squamous cell carcinoma

Background. The purpose of this study was to characterize the expression of CD200, a membrane protein that functions in immune evasion, to examine its correlations with cancer stem cell (CSC)-like features and analyze its response to chemotherapy and radiation in human papillomavirus (HPV)-positive (+) and negative (-) head and neck squamous cell carcinomas (HNSCCs). Methods. CD200 expression was analyzed in several HNSCC cell lines. CD200 was overexpressed in HPV(+) murine tonsil epithelial cells, its effects on Shh and Bmi-1 were examined in vitro, and tumor growth and response to chemoradiation were analyzed in vitro and in vivo. Results. CD200 was diversely expressed and consistently associated with expression of Bmi-1 and Shh. Overexpression of CD200 induced Bmi-1 and Shh. Tumors grew similarly between C57BL/6 and Rag1^-/- C57BL/6 mice. CD200 expression enhanced the resistance to chemoradiation only in vivo. Conclusion. CD200 was related to CSC features and modulates response to chemoradiation in vivo. Attenuating this might be a potential therapeutic strategy.