Circ_0089761 accelerates colorectal cancer metastasis and immune escape via miR-27b-3p/PD-L1 axis

Circular RNAs have been implicated as critical regulators in the initiation and progression of colorectal cancer (CRC). This study was intended to elucidate the functional significance of the circ_0089761/miR-27b-3p/programmed cell death ligand 1 (PD-L1) axis in CRC. Our findings indicated that circ_0089761 expression was significantly elevated in CRC tissues and cell lines. Furthermore, the high expression of circ_0089761 was correlated with TNM stage and tumor size. Silencing circ_0089761 inhibited CRC cell proliferation, migration, and invasion, and increased apoptosis. Mechanistically, circ_0089761 facilitated its biological function by binding to miR-27b-3p to upregulate PD-L1 expression in CRC. Coculture experiments confirmed that low expression of circ_0089761 impeded CD8 + T cell apoptosis and depletion, activated CD8 + T cell function, and increased secretion of the immune effector cytokines IFN-γ, TNF-α, perforin, and granzyme-B. MiR-27b-3p inhibition or PD-L1 overexpression partially impeded CD8 + T cell function. The circ_0089761/miR-27b-3p/PD-L1 axis is postulated to exert pivotal functions in the mechanistic progression of CRC. Furthermore, it holds promising prospects as a feasible biomarker and therapeutic target for CRC.