Figure 1.

Schematic representation showing the mechanism of ATRA‐LNP on activating anti‐tumor immune responses in the gut. Specifically, ATRA‐LNP encapsulating mRNA vaccine and ATRA was administered through intramuscular injections (I.M.). ATRA‐LNP was then taken up by antigen‐presenting cells such as dendritic cells and expressed encoded tumor antigen. During antigen presentation, the presence of ATRA triggered the expression of gut‐homing receptors, CCR9, and α4β7, on activated T cells, which could then infiltrate into orthotopic colorectal tumors and kill tumor cells.