Proteasome regulator PSME4 reduces cellular inflammation and promotes an immunosuppressive tumor microenvironment

We observed that proteasome regulator PSME4 inhibits antigen presentation and reduces cellular inflammation in lung adenocarcinoma. As tumor inflammation and antigenicity are key to anti-tumor immunity, we examined the effect of PSME4 in vivo by injecting mice with either KP1.9 or KP1.9PSME4_KD lung adenocarcinoma. We analyzed the changes in the immune milieu by performing single cell RNA sequencing (sc-RNA seq) of CD45+ cells, 3 weeks following injection of tumor cells. This allowed us to examine the effect of PSME4 on the early immune response to the tumor.