Macrophage-specific Act1 Knockdown Promoted Adenoma-Adenocarcinoma Transition in Apcmin+/- Mice via Activation of the CXCL9/10-CXCR3 axis

macrophages involve in colorectal adenocarcinoma transition. Mouse MC38 colorectal cancer cells were co-cultured with BMDM from both anti-Act1 and Wildtype mice. MC38 cells have higher migration speed and express higher EMT markers including Snail, E-cadherins, and Twist after co-culture with anti-Act1 macrophage. Expression profiling by high throughput sequencing highlighted that by co-culturing with MC38 cells, anti-Act1 macrophage increase proinflammatory cytokines secretion and consequently activates cytokines receptor signaling pathway. Specifically, we identified the mechanism where CXCL9/10 from anti-Act1 macrophage interacted with CXCR3 receptor in MC38 cell to promote MC38 migration as well as EMT. Besides, coculturing with MC38 cells enhanced expressions of PD-L1 and MDSCs markers such as Arg1, iNOS, IDO1 in anti-Act1 macrophages. Among activating pathways, we reveal that anti-Act1 macrophage orchestrates NF-kB and STAT3 signaling pathways to upregulate CXCL9/10 secretion and PD-L1 expression. These findings demonstrate that anti-Act1 in macrophage induced a significant shift in MC38 cells gene expression, and modulating the macrophage-cancer is a viable strategy to assist PD-L1 immunotherapy. Bulk RNA-seq of mouse BMDM coculturing with mouse MC38 cells for 48h