Open Access

PD‑L1 expression levels on tumor cells affect their immunosuppressive activity

  • Authors:
    • Yang Zheng
    • You‑Chen Fang
    • Jing Li
  • View Affiliations

  • Published online on: September 20, 2019     https://doi.org/10.3892/ol.2019.10903
  • Pages: 5399-5407
  • Copyright: © Zheng et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Programmed cell death 1 (PD‑1) is an immuno‑​checkpoint receptor which is primarily expressed on T cells, monocytes, natural killer cells and macrophages. Programmed death‑ligand 1 (PD‑L1) is the primary ligand of PD‑1 and is constitutively expressed on antigen presenting cells, mesenchymal stem cells and bone marrow‑derived mast cells. In addition, PD‑L1 is also expressed on a wide range of tumor cells, including lung cancer, breast cancer and melanoma. PD‑1 and PD‑L1 are important members of the immunoglobulin super‑family and participate in immune regulation. In the present study, the immune‑suppressive effects of a number of tumor cell lines were determined. The breast tumor cell lines MCF‑7 and MDA‑MB‑231 displayed the largest inhibitory effects on T‑cell activation and cytokine secretion in a co‑culture system. The HepG2, A549 and A375 cells displayed limited inhibitory effects. MCF‑7 and MDA‑MB‑231 cells expressed the highest level of PD‑L1 among the cells used, which may explain their higher immuno‑suppressive effects. Compound A0‑L, a small molecule inhibitor of the PD‑1/PD‑L1 interaction, restored T cell functions. Additionally, it was demonstrated that the tumor cells with higher levels of PD‑L1 expression suppressed signaling pathways involved in T‑cell activation, such as the T‑cell receptor‑ zeta chain of T cell receptor associated protein kinase ZAP70‑RAS‑GTPase‑extracellular‑signal‑regulated kinases and CD28‑PI3K‑Akt serine/threonine kinases pathways. These findings suggest that tumor cells with higher expression levels of PD‑L1 may exhibit higher immuno‑suppressive activity, and that drugs targeting the PD‑1/PD‑L1 interaction may have improved therapeutic effects on tumors expressing higher levels of PD‑L1.
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November-2019
Volume 18 Issue 5

Print ISSN: 1792-1074
Online ISSN:1792-1082

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Spandidos Publications style
Zheng Y, Fang YC and Li J: PD‑L1 expression levels on tumor cells affect their immunosuppressive activity. Oncol Lett 18: 5399-5407, 2019.
APA
Zheng, Y., Fang, Y., & Li, J. (2019). PD‑L1 expression levels on tumor cells affect their immunosuppressive activity. Oncology Letters, 18, 5399-5407. https://doi.org/10.3892/ol.2019.10903
MLA
Zheng, Y., Fang, Y., Li, J."PD‑L1 expression levels on tumor cells affect their immunosuppressive activity". Oncology Letters 18.5 (2019): 5399-5407.
Chicago
Zheng, Y., Fang, Y., Li, J."PD‑L1 expression levels on tumor cells affect their immunosuppressive activity". Oncology Letters 18, no. 5 (2019): 5399-5407. https://doi.org/10.3892/ol.2019.10903