Compound kushen injection inhibits immune evasion of hepatocellular carcinoma cells via reducing O-GlcNAcylation of Pd-L1

The advancement of hepatocellular carcinoma (HCC) is associated with metabolic reprogramming and immune escape. Compound kushen injection (CKI) is a cancer therapeutic agent with a long history. O-GlcNAcylation is reported to regulate tumor progression. We aimed to investigate how CKI affects HCC cell glycolysis and immune evasion and then clarify the underlying O-GlcNAcylation regulatory mechanism. HCC cell lines and subcutaneous transplantation mice were treated with CKI, and glycolysis and immune evasion were analyzed. The O-GlcNAcylation was analyzed using immunoprecipitation and western blotting. The results showed that CKI inhibited the viability, glycolysis, and immune escape of HCC cells, as well as hindered tumor growth, glycolysis, and immune evasion in vivo. Induction of glycolysis caused by hypoxia reduced the effect of CKI on immune evasion. Besides, CKI reduced the O-GlcNAc levels and OGT transcription activity. Overexpression of OGT counteracted the inhibition of immune evasion caused by CKI. Additionally, OGT catalyzed the O-GlcNAcylation of PD-L1 and enhanced its stability. In conclusion, CKI suppresses immune evasion of HCC cells in association with glycolysis suppression, which is related to the reduction of PGT-mediated PD-L1 O-GlcNAcylation. These findings suggest that CKI possesses an anti-HCC effect, and targeting PD-L1 O-GlcNAcylation may improve its therapeutic efficacy on HCC.