PD-L1 induced by IFN-γ from tumor-associated macrophages via the JAK/STAT3 and PI3K/AKT signaling pathways promoted progression of lung cancer
- 1.4k Downloads
Interferon-γ (IFN-γ) is conventionally regarded as an inflammatory cytokine that has a pivotal role in anti-infection and tumor immune surveillance. It has been used clinically to treat a variety of malignancies. However, increased evidence has suggested IFN-γ can act to induce tumor progression. The role of IFN-γ in regulating antitumor immunity appears to be complex and paradoxical. The mechanism underlying the dual aspects of IFN-γ function in antitumor immunity is not clear.
(1) Lung cancer cells (A549 cells) were cultured with pleural effusion or supernatant of tumor-associated macrophages (TAMs supernatant), and the expression levels of PD-L1 were detected by flow cytometer. The invasion capacity was measured in vitro using trans-well migration assays. (2) Pleural effusion mononuclear cells (PEMC) were separated by Ficoll Hypaque gradient. The expression of interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, and INF-γ in the tumor-associated macrophages was analyzed by flow cytometry. (3) A549 cells were stimulated with IL-6, IL-10, TNF-α, or IFN-γ and then the expression levels were detected by flow cytometry. (4) The expression levels of phospho-ERK (p-ERK), phospho-AKT (p-AKT), and phospho-Sat3 (p-Stat3) were analyzed with Western blot after stimulation with IFN-γ. (5) Cotreatment of the A549 cells with MAPK/ERK-specific inhibitor PD98059, PI3K/AKT-specific inhibitor LY294002, or JAK/STAT3-specific inhibitor AG490, respectively, blocked IFN-γ-induced PD-L1 expression, and then PD-L1 expression was detected by flow cytometry.
We demonstrated that TAMs could induce the expression of PD-L1 by the secretion of IFN-γ through the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) signaling pathway and the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway in A549 cells. Furthermore, the signal pathway blockers LY294002 or AG490 could block the induced expression of PD-L1 by IFN-γ.
IFN-γ was not always successful as an antitumor agent. It also can promote tumor cells to evade immune surveillance. Researchers should be cautious in using IFN-γ as a therapeutic agent for cancer treatment.
KeywordsLung cancer Tumor microenvironment Tumor-associated macrophage Cytokine PD-L1 Signaling pathway
This study was funded by the National Natural Science Foundation of China (31270940 to J.-A. Huang), Clinical Medical Center of Suzhou (Szzx201502), Suzhou Key Laboratory for Respiratory Medicine (No. SZS201617); the Societal and Developmental Project of Suzhou (No. SS201630); and The Foundation of Health Care Rejuvenation by Science and Education (KJXW2016003 to Y.-Y. Zeng) and Clinical Key Specialty Project of China.
Compliance with ethical standards
Conflict of interest
The authors have no conflicts of interest to declare.
This work was approved to be performed by the Ethics Committee of the First Affiliated Hospital of Soochow University.
Informed consent was obtained from all individual participants included in the study.
- 25.Alberts DS, Marth C, Alvarez RD et al (2008) Randomized phase 3 trial of interferon gamma-1b plus standard carboplatin/paclitaxel versus carboplatin/paclitaxel alone for first-line treatment of advanced ovarian and primary peritoneal carcinomas: results from a prospectively designed analysis of progression-free survival. Gynecol Oncol 109(2):174–181CrossRefPubMedGoogle Scholar
- 26.Matsuura H, Sakaue M, Subbaramaiah K et al (1999) Regulation of cyclooxygenase-2 by interferon gamma and transforming growth factor alpha in normal human epidermal keratinocytes and squamous carcinoma cells. Role of mitogen-activated protein kinases. J Biol Chem 274:29138–29148CrossRefPubMedGoogle Scholar