Notch-1 induces M2 polarization of tumor-associated macrophages via the YAP/EZH2/FOXD1/CD47 signaling axis, thereby driving non-small cell lung cancer progression.

OBJECTIVE: To investigate the mechanism by which Notch1 induces M2 polarization of tumor-associated macrophages (TAMs) through regulation of the YAP/EZH2/JMJD3/PTEN/FOXD1/galectin-3/CD47 signaling pathway and its role in non-small cell lung cancer (NSCLC). METHODS: Bioinformatics analysis was utilized to identify Notch1 and M2 polarization-related genes. In vivo tumor progression was assessed using a subcutaneous xenograft tumor model in nude mice. In vitro experiments employed Western blot to detect relevant protein expression levels, real-time quantitative polymerase chain reaction (RT-qPCR) to detect IL-1β, TNF-α, arginase-1, and Cathepsin B/K, flow cytometry to detect apoptosis and proliferation, plate colony formation assay to detect clonogenic ability, scratch assay to detect cell migration, and Transwell assay to detect cell invasion. RESULTS: In NSCLC, tumor cells activate Notch1 signaling through Jagged-1, triggering NICD/RBP-J-mediated YAP synthesis and activation. Activated YAP enhances Jagged-1 expression through positive feedback, forming a Notch1/YAP signal amplification loop, and inhibits PTEN expression by activating EZH2 (in antagonism with JMJD3). PTEN deficiency relieves dual inhibition of the PI3K/Hippo pathways, leading to sustained YAP activation, which subsequently drives FOXD1 transcription and downstream expression of galectin-3 and C-MYC. C-MYC not only promotes tumor proliferation and invasion but also induces high expression of the immune checkpoint molecule CD47. CD47 binds to SIRPα on the surface of tumor-associated TAMs, blocking M1 polarization, driving M2 polarization, and activating the STAT3/PD-L1 axis. PD-L1 further induces endoplasmic reticulum stress (ERS) and promotes Cathepsin K/B expression. CONCLUSION: Notch1 induces M2 polarization of TAMs by activating the YAP/EZH2/JMJD3/PTEN/FOXD1/galectin-3/CD47 signaling pathway, thereby promoting NSCLC progression. This study provides important clues for understanding the molecular mechanisms of NSCLC and identifying potential therapeutic targets.