LncRNA PROX1 antisense RNA 1 promotes PD-L1-mediated proliferation, metastasis, and immune escape in colorectal cancer by interacting with miR-520d

It was recently found that lncRNA PROX1 antisense RNA 1 (PROX1-AS1) manifested oncogenicity in a variety of malignancies. This work intended to investigate the molecular mechanisms of PROX1-AS1 in colorectal cancer (CRC) development and immune evasion. In this study, both PROX1-AS1 and PD-L1 expressions were lifted in CRC tissues and cells. PROX1-AS1 interference restrained CRC cell proliferation, migration, invasion, as well as CD8(+) T-lymphocyte apoptosis, but increased the cytotoxicity and percentage of CD8(+) T lymphocytes. The inhibitory effects of PROX1-AS1 inhibition on CRC progression and immune escape were positively related to PD-L1 suppression. PROX1-AS1 absorbed miR-520d to upregulate PD-L1 expression. PROX1-AS1 facilitated CRC progression and immune escape by targeting miR-520d. Furthermore, PROX1-AS1 deletion impaired CRC tumor growth in vivo. To sum up, this study affirmed that PROX1-AS1 could absorb miR-520d to upregulate PD-L1 in CRC, thereby promoting tumor progression and immune escape.