GM-CSF derived from the inflammatory microenvironment potentially enhanced PD-L1 expression on tumor-associated macrophages in human breast cancer.

ABSTRACT: Ever since immune checkpoint inhibitors have been approved for anti-cancer therapy in several cancers, including triple-negative breast cancer, the significance of programmed death-1 ligand 1 (PD-L1) expression in the tumor immune microenvironment has been a topic of interest. In the present study, we investigated the detailed mechanisms of PD-L1 overexpression on tumor-associated macrophages (TAMs) in breast cancer. In in vitro culture studies using human monocyte-derived macrophages, lymphocytes, and breast cancer cell lines, PD-L1 overexpression on macrophages was induced by the conditioned medium (CM) of activated lymphocytes, but not that of cancer cells. Granulocyte-macrophage colony-stimulating factor (GM-CSF) derived from activated lymphocytes was found to be involved in PD-L1 over

SUBMITTER: Yonemitsu K 

PROVIDER: S-EPMC9283541 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature