Effect of MAOI on antitumor immunity in a B16-OVA melanoma tumor model

MAOIs, a class of antidepressant drugs that inhibit the degradation of monoamine neurotransmitters including serotonin, have been shown to significantly enhance antitumor immunity. Employig a single cell sequencing approch using 10xGemonics scRNAseq, we investigated how MAOI alters tumor-infiltrating CD8 T cell compartment and signaling pathways. This study provides new insights into the mechanistic differences in how MAOIs and SSRIs regulate CD8 T cell antitumor immunity. Overall design: C57BL/6J mice were challenged with B16-OVA melanoma and then daily treated with a MAOI (phenelzine) starting from day 3. CD45+ tumor-infiltrating immune cells (TIIs) were sorted from day 10 B16-OVA tumors and then subjected to scRNA-seq analysis.