1. Anti-PD-L1 antibodies promote cellular proliferation by activating the PD-L1-AXL signal relay in liver cancer cells.
- Author
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Tanaka T, Koga H, Suzuki H, Iwamoto H, Sakaue T, Masuda A, Nakamura T, Akiba J, Yano H, Torimura T, and Kawaguchi T
- Subjects
- Humans, Mice, Animals, Cell Line, Tumor, Immune Checkpoint Inhibitors pharmacology, Immune Checkpoint Inhibitors therapeutic use, Receptor Protein-Tyrosine Kinases immunology, Antibodies, Monoclonal, Humanized pharmacology, Antibodies, Monoclonal, Humanized therapeutic use, Antibodies, Monoclonal pharmacology, Antibodies, Monoclonal therapeutic use, Proto-Oncogene Proteins metabolism, Axl Receptor Tyrosine Kinase, Xenograft Model Antitumor Assays, Liver Neoplasms pathology, Liver Neoplasms drug therapy, Liver Neoplasms immunology, Cell Proliferation drug effects, B7-H1 Antigen metabolism, Carcinoma, Hepatocellular pathology, Carcinoma, Hepatocellular drug therapy, Carcinoma, Hepatocellular immunology, Signal Transduction
- Abstract
Background: Immune checkpoint inhibitors (ICIs) are emerging treatments for advanced hepatocellular carcinoma (HCC); however, evidence has shown they may induce hyperprogressive disease via unexplained mechanisms., Methods: In this study, we investigated the possible stimulative effect of ICIs on programmed cell death-ligand 1 (PD-L1)-harboring liver cancer cells under immunocompetent cell-free conditions., Results: The sarcomatous HAK-5 cell line displayed the highest expression of PD-L1 among 11 human liver cancer cell lines used in this study. HLF showed moderate expression, while HepG2, Hep3B, and HuH-7 did not show any. Moreover, sarcomatous HCC tissues expressed high levels of PD-L1. We observed approximately 20% increase in cell proliferation in HAK-5 cells treated with anti-PD-L1 antibodies, such as durvalumab and atezolizumab, for 48 h compared with that of those treated with the control IgG and the anti-PD-1 antibody pembrolizumab. No response to durvalumab or atezolizumab was shown in PD-L1-nonexpressing cells. Loss-of-function and gain-of-function experiments for PD-L1 in HAK-5 and HepG2 cells resulted in a significant decrease and increase in cell proliferation, respectively. Phosphorylated receptor tyrosine kinase array and immunoprecipitation revealed direct interactions between PD-L1 and AXL in tumor cells. This was stabilized by extrinsic anti-PD-L1 antibodies in a glycosylated PD-L1-dependent manner. Activation of AXL, triggering signal relay to the Akt and Erk pathways, boosted tumor cell proliferation both in vitro and in xenografted tumors in NOD/SCID mice., Conclusion: Collectively, this suggests that anti-PD-L1 antibodies stimulate cell proliferation via stabilization of the PD-L1-AXL complex in specific types of liver cancer, including in HCC with mesenchymal components., Significance: Therapeutic anti-PD-L1 antibodies promote cell proliferation by stabilizing the PD-L1-AXL complex in PD-L1-abundant neoplasms, including in HCC with mesenchymal components. Such a mechanism may contribute to the development of hyperprogressive disease., (© 2023. Asian Pacific Association for the Study of the Liver.)
- Published
- 2024
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