CD47 Overexpression Is Associated with Epstein–Barr Virus Infection and Poor Prognosis in Patients with Nasopharyngeal Carcinoma

Abstract

Zhi-Hui Wang,1– 3,* Xiao-Feng Pei,2,3,* Zhi-Quan Zhu,2,3,* Zhong Lin,2,3 Yin-Yan Mao,2,3 Xiao-Lu Xu,2,3 You-Li Luo,4 Li Zhang,1 Pei-Jian Peng2,3 1State Key Laboratory of Oncology in South China, Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, People’s Republic of China; 2Department of Thoracic Oncology, The Cancer Center of the Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong, People’s Republic of China; 3Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong, People’s Republic of China; 4Department of Interventional Oncology, The Cancer Center of the Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong, People’s Republic of China*These authors contributed equally to this workCorrespondence: Li ZhangState Key Laboratory of Oncology in South China, Department of Medical Oncology, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou 510060, Guangdong, People’s Republic of ChinaTel [phone]Fax [phone]Email [email protected] PengGuangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong, People’s Republic of China, Department of Thoracic Oncology, The Cancer Center of the Fifth Affiliated Hospital of Sun Yat-sen University, 52 Meihua Road East, Zhuhai 519000, Guangdong, People’s Republic of ChinaTel [phone]Fax [phone]Email [email protected]: Little is known about the clinical significance of CD47 expression and its association with Epstein–Barr virus (EBV) infection in patients with nasopharyngeal carcinoma (NPC). The aim of this study was to clarify the prognostic value and role of CD47 in EBV-associated NPC.Materials and Methods: Sixty-six cases of non-metastatic NPC were retrospectively reviewed. Tissues were collected for immunohistochemical staining of CD47 and the EBV-encoded oncoprotein latent membrane protein 1 (LMP1). Western blotting and quantitative real-time PCR were performed to determine the CD47 and LMP1 levels in common human NPC cell lines. Additionally, CD47 and LMP1 expression in a constructed EBV-positive human NPC cell (CNE-2-EBV+) and a stable cell line transfected with LMP1 plasmid (CNE-2-LMP1) was assessed. Next, we used Western blotting to assess the decrease in CD47 expression on CNE-2-LMP1 cells after transfecting them with small interfering RNA (siRNA)-targeting LMP1.Results: In NPC patients, CD47 overexpression was significantly associated with disease recurrence (P=0.010), leading to poorer disease-free survival (DFS; P=0.002) and overall survival (P=0.021). Multivariate Cox proportional hazards models demonstrated that CD47 (HR=5.452, P=0.016) was an independent prognostic factor of DFS. Moreover, CD47 expression was associated with plasma EBV-DNA copy number and LMP1 tissue expression. Among the human NPC cell lines, CD47 and LMP1 expression was notably higher in the EBV-positive C666-1 cell line than in the EBV-negative cell lines. Furthermore, EBV infection upregulated CD47 expression via LMP1-mediated pathways in human NPC cells.Conclusion: This study indicated that CD47 is related to EBV infection in NPC patients, and it is a feasible biomarker.Keywords: CD47, Epstein–Barr virus, latent membrane protein 1, nasopharyngeal carcinoma

Keywords

• cd47
• epstein–barr virus
• latent membrane protein 1
• nasopharyngeal carcinoma