Inhibitors of cyclin-dependent kinase-2 (CDK2) are commonly used against several solid tumors, and their primary mechanisms of action were thought to include cell proliferation arrest, induction of cancer cell apoptosis and induction of differentiation. Here, we found that CDK2 inhibition by either small molecular inhibitors or genetic Cdk2 deficiency promoted antitumor immunity in murine models of fibrosarcoma and lung carcinoma. Mechanistically, CDK2 inhibition reduced phosphorylation of RB protein and transcription of E2F-mediated DNA methyltransferase 1 (DNMT1), which resulted in increased expression of endogenous retroviral RNA and type I IFN (IFN-I) response. The increased IFN-I response subsequently promoted antitumor immunity by enhancing tumor antigen presentation and CD8+ T-cell infiltration. Our studies provide evidence that inhibition of CDK2 in cancer cells suppresses tumor growth by enhancing antitumor immune responses in the tumor microenvironment, suggesting a new mechanism to enhance antitumor immunity by CDK2 inhibitors.

A growing body of literature suggests that most chronic autoimmune diseases are associated with inappropriate inflammation mediated by Toll-like receptor (TLR) 3, TLR7/8, or TLR9. Therefore, research into blocking TLR activation to treat these disorders has become a hot topic. Here, we report the immunomodulatory properties of a nonstimulatory CpG-containing oligodeoxynucleotide (CpG-ODN), CpG-c41, which had previously only been known as a TLR9 antagonist. In this study, we found that both in vitro and in vivo CpG-c41 decreased levels of various proinflammatory factors that were induced by single activation or coactivation of intracellular TLRs, but not membrane-bound TLRs, no matter what downstream signal pathways the TLRs depend on. Moreover, CpG-c41 attenuated excessive inflammation in the imiquimod-induced psoriasis-like mouse model of skin inflammation by suppressing immune cell infiltration and release of inflammatory factors. We also found evidence that the immunosuppressive effects of CpG-c41 on other intracellular TLRs are mediated by a TLR9-independent mechanism. These results suggest that CpG-c41 acts as an upstream of signaling cascades, perhaps on the processes of ligand internalization and transfer. Taken together, these results suggest that CpG-c41 disrupts various aspects of intracellular TLR activation and provides a deeper insight into the regulation of innate immunity.

BackgroundThough immunological abnormalities have been proven involved in the pathogenesis of lymphoma, the underlying mechanism remains unclear.MethodsWe investigated 25 single nucleotide polymorphisms (SNPs) of 21 immune‐related genes and explored their roles in lymphoma. The genotyping assay of the selected SNPs was used by the Massarray platform. Logistic regression and Cox proportional hazards models were used to analyze the associations of SNPs and the susceptibility of lymphoma or clinical characteristics of lymphoma patients. In addition, Least Absolute Shrinkage and Selection Operator regression was used to further analyze the relationships with the survival of lymphoma patients and candidate SNPs, and the significant difference between genotypes was verified by the expression of RNA.ResultsBy comparing 245 lymphoma patients with 213 healthy controls, we found eight important SNPs related to the susceptibility of lymphoma, which were involved in JAK–STAT, NF‐κB and other functional pathways. We further analyzed the relationships between SNPs and clinical characteristics. Our results showed that both IL6R (rs2228145) and STAT5B (rs6503691) significantly contributed to the Ann Arbor stages of lymphoma. And the STAT3 (rs744166), IL2 (rs2069762), IL10 (rs1800871), and PARP1 (rs907187) manifested a significant relationship with the peripheral blood counts in lymphoma patients. More importantly, the IFNG (rs2069718) and IL12A (rs6887695) were associated with the overall survival (OS) of lymphoma patients remarkably, and the adverse effects of GC genotypes could not be offset by Bonferroni correction for multiple comparison in rs6887695 especially. Moreover, we determined that the mRNA expression levels of IFNG and IL12A were significantly decreased in patients with shorter‐OS genotypes.ConclusionsWe used multiple methods of analysis to predict the correlations between lymphoma susceptibility, clinical characteristics or OS with SNPs. Our findings reveal that immune‐related genetic polymorphisms contribute to the prognosis and treatment of lymphoma, which may serve as promising predictive targets.