EBV-driven LMP1 and IFN-γ up-regulate PD-L1 in nasopharyngeal carcinoma: Implications for oncotargeted therapy

Oncotarget. 2014 Dec 15;5(23):12189-202. doi: 10.18632/oncotarget.2608.

Abstract

PD-L1 expression is a feature of Epstein-Barr virus (EBV) associated malignancies such as nasopharyngeal carcinoma (NPC). Here, we found that EBV-induced latent membrane protein 1 (LMP1) and IFN-γ pathways cooperate to regulate programmed cell death protein 1 ligand (PD-L1). Expression of PD-L1 was higher in EBV positive NPC cell lines compared with EBV negative cell lines. PD-L1 expression could be increased by exogenous and endogenous induction of LMP1 induced PD-L1. In agreement, expression of PD-L1 was suppressed by knocking down LMP1 in EBV positive cell lines. We further demonstrated that LMP1 up-regulated PD-L1 through STAT3, AP-1, and NF-κB pathways. Besides, IFN-γ was independent of but synergetic with LMP1 in up-regulating PD-L1 in NPC. Furthermore, we showed that PD-L1 was associated with worse disease-free survival in NPC patients. These results imply that blocking both the LMP1 oncogenic pathway and PD-1/PD-L1 checkpoints may be a promising therapeutic approach for EBV positive NPC patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • B7-H1 Antigen / biosynthesis*
  • Blotting, Western
  • Carcinoma
  • Disease-Free Survival
  • Enzyme-Linked Immunosorbent Assay
  • Epstein-Barr Virus Infections / metabolism*
  • Female
  • Flow Cytometry
  • Fluorescent Antibody Technique
  • Gene Expression Regulation, Neoplastic / physiology
  • Gene Expression Regulation, Viral / physiology
  • Herpesvirus 4, Human
  • Humans
  • Interferon-gamma / metabolism*
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • Nasopharyngeal Carcinoma
  • Nasopharyngeal Neoplasms / metabolism
  • Nasopharyngeal Neoplasms / mortality
  • Nasopharyngeal Neoplasms / virology*
  • RNA, Small Interfering
  • Real-Time Polymerase Chain Reaction
  • Transfection
  • Up-Regulation
  • Viral Matrix Proteins / metabolism*
  • Young Adult

Substances

  • B7-H1 Antigen
  • CD274 protein, human
  • EBV-associated membrane antigen, Epstein-Barr virus
  • RNA, Small Interfering
  • Viral Matrix Proteins
  • Interferon-gamma