Title : EBV latent membrane protein 1 augments gammer-delta T cell cytotoxicity against nasopharyngeal carcinoma by induction of butyrophilin molecules
Nasopharyngeal carcinoma (NPC) is diverse cancer with no well-defined tumor antigen, associated with oncogenic Epstein-Barr Virus (EBV), and with usually late-stage diagnosis and survival <40%. Current radio- and chemotherapy have low effectiveness and cause adverse effects. In this regard, adoptive immunotherapy using gd T cells has potential if enhanced expression of butyrophilin molecules can be achieved in the NPC.
Methods: Human gd T cells were expanded (with Zol or PTA) and used for cytotoxicity assay against NPC cells, which were treated with the EBV EBNA1-targeting peptide (L2) P4. Effect of (L2) P4 on BTN2A1/BTN3A1 expression in NPC cells was examined by flow cytometry and Western blot. An NPC-bearing NSG mice model was established to test the effectiveness of P4 and adoptive gd T cells. Immunofluorescence was performed on NPC tissue sections to examine the presence of gd T cells and expression of BTN2A1 and BTN3A1. EBV gene expression post-(L2) P4 treatment was assessed by qRT-PCR, and the relationship of LMP1, NLRC5 and BTN2A1/BTN3A1 was examined by transfection, reporter assay, Western blot, and inhibition experiments.
Results: Zol- or PTA-expanded the Vd2 subset of gd T cells that exerted killing against certain NPC cells. (L2) P4 reactivates latent EBV, which increased BTN2A1 and BTN3A1 expression and conferred higher susceptibility towards Vd2 T cells cytotoxicity in vitro, and enhanced tumor regress in vivo by adoptive Vd2 T cells likely due to P4 induced expression of BTN2A1 and BTN3A1 in the tumors. Mechanistically, (L2) P4 induced EBV LMP1, leading to IFN-g/p-JNK and NLRC5 activation and subsequent expression of BTN2A1/BTN3A1.
Conclusions: This study demonstrated the effectiveness of using the EBV-targeting probe (L2) P4 and adoptive gd T cells as a promising combinatorial immunotherapy against NPC. The identification of the LMP1-IFN-g/p-JNK-NLRC5-BTN2A1/BTN3A1 axis may lead to new insight and therapeutic targets against NPC and other EBV+ tumors.
Audience Take Away Notes:
- A better understanding of the mechanism of nasopharyngeal carcinoma and related immunotherapy methods.
- Learn about the possibility of gd T cells in immunotherapy for nasopharyngeal cancer.
- The understanding of the mechanism that P4-induced LMP1 can trigger BTN2A1/BTN3A1 axis has the potential for future development as a combinatorial immunotherapy with adoptive gd T cells in treating NPCs and other tumors.