NLRP3 inflammasome activation plays a carcinogenic role through effector cytokine IL-18 in lymphoma

Abstract

Inflammasomes play important roles in the pathogenesis of tumors, but the roles of NLRP3 inflammasome in the lymphoma remain unclear. Activated NLRP3 inflammasome induces the maturation of its effector cytokine IL-18 which functions in the development of cancer. Here, we investigated the polymorphism and expression of NLRP3 inflammasome related genes and explored their function in lymphoma. We found that IL-18 (rs1946518) and NFκB94 ins/del (rs28362491) contributed to lymphoma susceptibility and allele G in IL-18 was significantly associated with the risk of lymphoma. The mRNA and plasma expression levels of IL-18 were significantly elevated in primary lymphoma patients and decreased after remission. NLRP3 inflammasome could be activated by ATP plus LPS in lymphoma cells accompanied with the increasing expression of NLRP3-related genes. NLRP3 inflammasome activation reduced the dexamethasone-induced proliferation-inhibiting effect by promoting cells into S phase. NLRP3 inflammasome activation promoted lymphoma cells proliferation and inhibited apoptosis through up-regulation of c-myc and bcl-2, and down-regulation of TP53 and bax, and then reduced the anti-tumor effect of dexamethasone. Similar with the activation of NLRP3, the effector cytokine IL-18 also had the proliferation-promoting, apoptosis-inhibiting and resistance-reducing effects on lymphoma cells via shifting the balance of c-myc/TP53 and bcl-2/bax. Moreover, neutralizing IL-18 has the opposite effects. In conclusion, NLRP3 inflammasome contributes to the susceptibility and plays a carcinogenic role through its effector cytokine IL-18 in lymphoma.