Erlotinib: An enhancer of radiation therapy in nasopharyngeal carcinoma

The aim of this study was to explore the effects of erlotinib combined with radiation on human nasopharyngeal carcinoma (NPC) radiosensitivity using the CNE1 and CNE2 cell lines. Human NPC cells were treated with erlotinib and/or radiation. The effect of erlotinib on the radiosensitivity of the cells was detected using a clonogenic cell survival assay. The rate of apoptosis and the cell cycle were evaluated using flow cytometry. An NPC xenograft model in NOD-SCID mice was used to evaluate the efficacy of the combination therapy of erlotinib with radiation. Erlotinib enhanced the sensitivity of the CNE1 and CNE2 cells to radiation, with sensitization enhancement ratios (SERs) of 1.076 and 1.109, respectively. Erlotinib combined with radiation induced G2/M phase cell cycle arrest in the two cell lines. The mouse tumor model demonstrated a significant reduction in NPC tumor volume in mice treated with erlotinib in combination with radiation when compared with that in mice treated with radiation alone. Erlotinib combined with radiation provoked G2-M phase cell cycle arrest, thereby enhancing the sensitivity of the NPC cells to radiation.