TY - JOUR AB - Programmed death‑ligand 1 (PD‑L1), an immune co‑stimulatory molecule, is expressed on various cancer cells and the surface of immune cells. Its overexpression on tumor cells suppresses the immune response to promote tumor cell immune escape. The present study demonstrated that PD‑L1 was critical in head and neck squamous cell carcinoma (HNSCC) carcinogenesis. Immunohistochemical analysis of HNSCC tissue microarrays revealed that PD‑L1 was overexpressed in tumor tissue, and its expression increased as tumor malignancy progressed (from grade I to IV). Subsequently, the expression of PD‑L1 was knocked down or overexpressed in the HNSCC cell lines Cal‑27 and Fadu. It was demonstrated that PD‑L1 significantly induced HNSCC cell proliferation and colony forming ability. Cell proliferation was also promoted in Cal‑27 cell xenograft BALB/c nude mice. In addition, it was determined by western blotting that the PD‑L1‑mediated increase in HNSCC cell proliferation may have been associated with the activation of mammalian target of rapamycin (mTOR) signaling pathway. Furthermore, mTOR inhibitor (rapamycin) prevented the increase in proliferation. Based on these results, it was concluded that PD‑L1 promoted cell proliferation of HNSCC cells through mTOR signaling, and blocking PD‑L1 may be conducive in HNSCC therapy. AD - Department of Otolaryngology‑Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China Research Institute of Otolaryngology‑Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China AU - Zheng,Anyuan AU - Li,Fen AU - Chen,Fuhai AU - Zuo,Jingjing AU - Wang,Lei AU - Wang,Yongping AU - Chen,Shiming AU - Xiao,Bokui AU - Tao,Zezhang DA - 2019/05/01 DO - 10.3892/or.2019.7053 EP - 2843 IS - 5 JO - Oncol Rep KW - head and neck squamous cell carcinoma programmed death‑ligand 1 proliferation mammalian target of rapamycin PY - 2019 SN - 1021-335X 1791-2431 SP - 2833 ST - PD‑L1 promotes head and neck squamous cell carcinoma cell growth through mTOR signaling T2 - Oncology Reports TI - PD‑L1 promotes head and neck squamous cell carcinoma cell growth through mTOR signaling UR - https://doi.org/10.3892/or.2019.7053 VL - 41 ER -