Inhibition of MAN2A1 enhances tumor response to anti-PD-L1

Immune checkpoint blockade (ICB) has shown remarkable efficacy, but in only a minority of cancer patients, suggesting the need to develop additional treatment strategies.We integrated transcriptional profiles of treatment-naïve human tumors and functional CRISPR screens to identify glycometabolism genes with immunomodulatory effects. We identified MAN2A1, encoding an enzyme in N-glycan maturation, as a key immunomodulatory gene. Analyses of public immune checkpoint blockade trial data also suggested a synergy between MAN2A1 inhibition and anti-PD-L1 treatment. Loss of Man2a1 in cancer cells increased their sensitivity to T cell-mediated killing. Man2a1 knockout enhanced response to anti-PD-L1 treatment and facilitated higher cytotoxic T cell infiltration in tumors under anti-PD-L1 treatment. Furthermore, a pharmacological inhibitor of MAN2A1, swainsonine, synergized with anti-PD-L1 in syngeneic melanoma tumor model, whereas each treatment alone had little effect. Overall design: Wildtype or Man2a1 knockout B16F10 treated with IgG isotype control or anti-PD-L1 or swainsonine or the combination of anti-PD-L1 and swainsonine.