1. Academic Validation
  2. Green Tea Catechin Is an Alternative Immune Checkpoint Inhibitor that Inhibits PD-L1 Expression and Lung Tumor Growth

Green Tea Catechin Is an Alternative Immune Checkpoint Inhibitor that Inhibits PD-L1 Expression and Lung Tumor Growth

  • Molecules. 2018 Aug 18;23(8):2071. doi: 10.3390/molecules23082071.
Anchalee Rawangkan 1 2 Pattama Wongsirisin 3 4 Kozue Namiki 5 6 Keisuke Iida 7 Yasuhito Kobayashi 8 Yoshihiko Shimizu 9 Hirota Fujiki 10 Masami Suganuma 11 12
Affiliations

Affiliations

  • 1 Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan. [email protected].
  • 2 Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama 362-0806, Japan. [email protected].
  • 3 Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan. [email protected].
  • 4 Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama 362-0806, Japan. [email protected].
  • 5 Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan. [email protected].
  • 6 Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama 362-0806, Japan. [email protected].
  • 7 Molecular Chirality Research Center and Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan. [email protected].
  • 8 Saitama Cardiovascular and Respiratory Center, Kumagaya, Saitama 360-0197, Japan. [email protected].
  • 9 Saitama Cardiovascular and Respiratory Center, Kumagaya, Saitama 360-0197, Japan. [email protected].
  • 10 Faculty of Medicine, Saga University, Saga 849-8501, Japan. [email protected].
  • 11 Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan. [email protected].
  • 12 Research Institute for Clinical Oncology, Saitama Cancer Center, Saitama 362-0806, Japan. [email protected].
Abstract

The Anticancer activity of immune checkpoint inhibitors is attracting attention in various clinical sites. Since green tea catechin has cancer-preventive activity in humans, whether green tea catechin supports the role of immune checkpoint inhibitors was studied. We here report that (-)-epigallocatechin gallate (EGCG) inhibited programmed cell death ligand 1 (PD-L1) expression in non⁻small-cell lung Cancer cells, induced by both interferon (IFN)-γ and epidermal growth factor (EGF). The mRNA and protein levels of IFN-γ⁻induced PD-L1 were reduced 40⁻80% after pretreatment with EGCG and green tea extract (GTE) in A549 cells, via inhibition of JAK2/STAT1 signaling. Similarly, EGF-induced PD-L1 expression was reduced about 37⁻50% in EGCG-pretreated Lu99 cells through inhibition of EGF receptor/Akt signaling. Furthermore, 0.3% GTE in drinking water reduced the average number of tumors per mouse from 4.1 ± 0.5 to 2.6 ± 0.4 and the percentage of PD-L1 positive cells from 9.6% to 2.9%, a decrease of 70%, in lung tumors of A/J mice given a single intraperitoneal injection of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In co-culture experiments using F10-OVA melanoma cells and tumor-specific CD3+ T cells, EGCG reduced PD-L1 mRNA expression about 30% in F10-OVA cells and restored interleukin-2 mRNA expression in tumor-specific CD3+ T cells. The results show that green tea catechin is an immune checkpoint inhibitor.

Keywords

(−)-epigallocatechin gallate; epidermal growth factor; immune checkpoint; interferon-γ; lung tumor.

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