Abstract
Programmed death ligand 1 (PD-L1), an important immune checkpoint molecule, is abnormally activated in non-small cell lung cancer (NSCLC), which can interact with programmed death 1 to aid cancer cells in evading immune surveillance. Furthermore, tumor driver genes may be involved in the occurrence and development of NSCLC and have a potential role in PD-L1-mediated immune escape mechanisms. Therefore, the present study aimed to assess the behavioral and regulatory mechanisms by which circular RNA ENTPD7 (circENTPD7; hsa_circ_0019421) induces an immune response in the progression of NSCLC cells. In brief, circENTPD7, insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) and PD-L1 expression were assessed using reverse transcription-quantitative PCR, and IGF2BP2 and PD-L1 protein expression levels were evaluated using western blotting. Subsequently, the proliferation, migration, invasion and immune escape of NSCLC cells were assessed using a Cell Counting Kit-8 assay, Transwell assay, T cell co-culture assay, FITC ester assay, flow cytometry and ELISA. The experimental results revealed that circENTPD7, IGF2BP2 and PD-L1 levels were significantly elevated in NSCLC cells. CircENTPD7 knockdown suppressed the malignant phenotype of NSCLC cells, whereas overexpression of IGF2BP2 counteracted these effects, indicating that circENTPD7 contributed to the proliferation and metastasis of NSCLC cells by upregulating IGF2BP2. Furthermore, overexpression of IGF2BP2 accelerated the proliferation, metastasis and immune escape processes of NSCLC cells by upregulating PD-L1. Collectively, the results indicate that circENTPD7 contributes to the malignant progression of NSCLC cells by modulating the IGF2BP2/PD-L1 axis-mediated immune escape.