Open Access

Increased expression of PD‑L1 by the human papillomavirus 16 E7 oncoprotein inhibits anticancer immunity

  • Authors:
    • Chaoqi Liu
    • Jiao Lu
    • Huiqun Tian
    • Wei Du
    • Lin Zhao
    • Jing Feng
    • Ding Yuan
    • Zhiying Li
  • View Affiliations

  • Published online on: Thursday, January 5, 2017
  • Pages:1063-1070 DOI: 10.3892/mmr.2017.6102
0

Abstract

Cytotoxic T lymphocyte dysfunction is frequently associated with PD‑L1/PD‑1 pathway activation, and is a principal obstacle in cancer therapy. In the present study, the mechanisms underlying the human papillomavirus (HPV)‑induced evasion of cervical cancer cells to the host immune system via the programmed death ligand  1/programmed death 1 (PD‑L1/PD‑1) signaling pathway was investigated. A significant increase in the expression of the HPV16E7 viral protein and PD‑L1 in cervical tissues was observed when compared with normal cervical tissues. In addition, a positive correlation between HPV16E7 and PD‑L1 expression was observed by immunohistochemical staining and reverse transcription‑polymerase chain reaction. Overexpressing HPV16E7 oncoprotein in the epithelial carcinoma of PC3 cells increased the expression level of the PD‑L1 protein and inhibited peripheral blood mononuclear cell (PBMC) proliferation and cytotoxic T lymphocyte (CTL) activity. Upon knockdown of HPV16E7 in HPV16‑associated CaSki cervical cancer cells with a relevant siRNA, a reduction in PD‑L1 protein expression was observed, as well as a significant increase in PBMC proliferation and CTL activity. A recombinant plasmid, MSCVPIG‑soluble PD‑1, was constructed and transfected into the CaSki cell line, and was co‑cultured with PBMCs. PBMC proliferation and CTL activity were observed to increase significantly. In conclusion, the results presented in the current study suggest that overexpression of PD‑L1, induced by HPV16E7, may be responsible for lymphocyte dysfunction. In addition, soluble PD‑1 may restore the function of tumor‑infiltrating lymphocytes by inhibiting the PD‑L1/PD‑1 signaling pathway. These results may provide a novel insight for immunotherapeutic approaches in the treatment of cervical cancer.

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March 2017
Volume 15 Issue 3

Print ISSN: 1791-2997
Online ISSN:1791-3004

2015 Impact Factor: 1.559
Ranked #48/123 Medicine Research and Experimental
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APA
Liu, C., Lu, J., Tian, H., Du, W., Zhao, L., Feng, J. ... Li, Z. (2017). Increased expression of PD‑L1 by the human papillomavirus 16 E7 oncoprotein inhibits anticancer immunity. Molecular Medicine Reports, 15, 1063-1070. http://dx.doi.org/10.3892/mmr.2017.6102
MLA
Liu, C., Lu, J., Tian, H., Du, W., Zhao, L., Feng, J., Yuan, D., Li, Z."Increased expression of PD‑L1 by the human papillomavirus 16 E7 oncoprotein inhibits anticancer immunity". Molecular Medicine Reports 15.3 (2017): 1063-1070.
Chicago
Liu, C., Lu, J., Tian, H., Du, W., Zhao, L., Feng, J., Yuan, D., Li, Z."Increased expression of PD‑L1 by the human papillomavirus 16 E7 oncoprotein inhibits anticancer immunity". Molecular Medicine Reports 15, no. 3 (2017): 1063-1070. http://dx.doi.org/10.3892/mmr.2017.6102