P23: Global S-nitrosylation analysis provides insight into tumor-induced immune suppression

To explore the functions of nitric oxide (NO) in immune regulation, we performed a large-scale, in vivo, site-specific analysis of S -nitrosylated proteins, from the spleens of naive (NTB) and mammary tumor bearing (TB) mice, yielding a dataset of 3352 S-nitrosylated sites on 1690 proteins. In TB mice S -nitrosylation mainly affects DNA replication/recombination/repair, nitrogen compound metabolic processes, translation, organelle organization and protein kinase cascades; whereas proteolysis, cell adhesion, protein transport and protein folding are primarily targeted by S -nitrosylation in naive mice. The GM-CSF pathway which controls normal hematopoiesis and myeloid differentiation is targeted by S -nitrosylation in TB mice. S -nitrosylation of DNA polymerase delta inhibitory to its function is also observed. Our data demonstrate the broad immune regulatory role of NO in both physiological and pathophysiological processes. Disclosure Nothing to disclose.