Positive feedback regulation between IL10 and EGFR promotes lung cancer formation

The role of IL10 in the tumorigenesis of various cancer types is still controversial. Here, we found that increased IL10 levels are correlated with a poor prognosis in lung cancer patients. Moreover, IL10 levels were significantly increased in the lungs and serum of EGFR(L858R)- and Kras4b(G12D)-induced lung cancer mice, indicating that IL10 might facilitate lung cancer tumorigenesis. IL10 knockout in EGFR(L858R) and Kras4b(G12D) mice inhibited the development of lung tumors and decreased the levels of infiltrating M(2) macrophages and tumor-promoting T(reg) lymphocytes. We also showed that EGF increases IL10 expression by enhancing IL10 mRNA stability, and IL10 subsequently activates JAK1/STAT3, Src, PI3K/Akt, and Erk signaling pathways. Interestingly, the IL10-induced recruitment of phosphorylated Src was critical for inducing EGFR through the activation of the JAK1/STAT3 pathway, suggesting that Src and JAK1 positively regulate each other to enhance STAT3 activity. Doxycycline-induced EGFR(L858R) mice treated with gefitinib and anti-IL10 antibodies exhibited poor tumor formation. In conclusion, IL10 and EGFR regulate each other through positive feedback, which leads to lung cancer formation.