KRAS mutation promotes immune escape of lung adenocarcinoma via ZNF24/SLC7A5/PD-L1 axis.

BACKGROUND: The imbalance of immune checkpoint molecules leads to immune escape of tumor cells. It has been established that KRAS mutation plays a key role in regulating PD-L1 expression of lung adenocarcinoma. However, the specific mechanism by which KRAS mutation regulates PD-L1 expression still needs further been clarified. METHODS: The relationship of KRAS mutation and ZNF24, SLC7A5 and PD-L1 expression in human lung adenocarcinoma tissues and cell lines were analyzed using relative assays. The effects of KRAS mutation on CD8(+) T cell-dependent anti-tumor immunity via the ZNF24/SLC7A5/PD-L1 axis were analyzed through in vitro and in vivo experiments. Additionally, we examined whether and how targeting ZNF24 inhibits KRAS mutation-induced PD-L1 expression and evaluated the effect of ZNF24 inhibition and PD-L1 blocking on CD8(+) T cell-dependent anti-tumor immunity. RESULTS: Our results found that KRAS mutation increases the expression of PD-L1 through the ZNF24/SLC7A5 axis and simultaneously inhibits the activation of CD8(+) T cells in lung adenocarcinoma. Importantly, we discovered that Daptomycin (DAPT) binds to ZNF24 and inactivates it, representing the first reported inhibitor of ZNF24. DAPT combined with Anti PD-L1 monoclonal antibody may enhance CD8(+) T cell-dependent anti-tumor immunity in KRAS mutated lung adenocarcinoma. CONCLUSION: Our study provides the first evidence that KRAS mutation promotes immune escape in lung adenocarcinoma through the ZNF24/SLC7A5/PD-L1 axis.