“Until now, the focus has been on finding ways to stimulate adaptive, or specific, immunity to reject tumors,” says Saleh, who is also Director, Inflammation and Cancer Program at McGill. “In contrast to this highly specialized form of immunity that is potentially patient- and cancer- specific, our findings show that innate immunity that broadly surveys tissues for the presence of 'danger' signals such as those produced in the cancer environment can also be harnessed for a more general cancer immunotherapy.”
Using mice that lack components of the innate immune system, the researchers found that spread of colorectal cancer to the liver was more aggressive than in mice that have an intact immune system. This suggested that innate immunity keeps cancer spread under check. The team was further able to identify the sensor (Nlrp3) and its effector cytokine (IL-18) that activates the ability of one’s natural killer cells to attack the tumor.
By identifying the nature of the innate immune system sensor and the mechanism by which this factor orchestrates tumor killing, the findings could have important implications for the further development of cancer immunotherapy, enabling potential therapeutic strategies that could harness this pathway to elicit tumor killing.
The study was supported with funding from CIHR and FRQS.