Mevalonate improves anti-PD-1/PD-L1 efficacy by stabilizing CD274 mRNA

Mevalonate metabolism plays an important role in regulating tumor growth and progression;however,its role in immune evasion and immune checkpoint modulation remains unclear.Here,we found that non-small cell lung cancer(NSCLC)patients with higher plasma mevalonate response better to antiPD-(L)1 therapy,as indicated by prolonged progression-free survival and overall survival.Plasma mevalonate levels were positively correlated with programmed death ligand-1(PD-L1)expression in tumor tissues.In NSCLC cell lines and patient-derived cells,supplementation of mevalonate significantly upregulated the expression of PD-L1,whereas deprivation of mevalonate reduced PD-L1 expression.Mevalonate increased CD274 mRNA level but did not affect CD274 transcription.Further,we confirmed that mevalonate improved CD274 mRNA stability.Mevalonate promoted the affinity of the AU-rich elementbinding protein HuR to the 3'-UTR regions of CD274 mRNA and thereby stabilized CD274 mRNA.By in vivo study,we further confirmed that mevalonate addition enhanced the anti-tumor effect of anti-PD-L1,increased the infiltration of CD8^(+)T cells,and improved cytotoxic function of T cells.Collectively,our findings discovered plasma mevalonate levels positively correlated with the therapeutic efficacy of anti-PD-(L)1 antibody,and provided the evidence that mevalonate supplementation could be an immunosensitizer in NSCLC.