The Role Of Nf-κB And IRF3in The Antitumor Immune Response

NF-kB, which plays a pivotal role in the development of autoimmune disease and cancer, is almost expressed in all cells types and regulate many target genes with a whole variety of functions. NF-kB is constitutively activated in many types of cancer, suggesting its role in cancergenesis and development. But relative rare studies focused on its antitumor activity. We are trying to explore the role of NF-kB and IRF3signaling pathways activation in antitumor immune response.Three charpters are presented:Charpter1. LLC-Mig, LLC-IKKβ, LLC-OVA-Mig, LLC-OVA-IKKβ cell lines were constructed first. Then the overexpression of constituvately activated IKKβ in LLC-IKKp and LLC-OVA-IKKp was verified. NF-kB dimmers, the molecular in the downstream of IKKs, translocated into nucleas, thereby inducing the target gene expression, such as cxcl1.Charpter2. LLC-Mig and LLC-IKKβ cells were subcutaneously injected in B57BL/6mice respectively, and tumor growth of the2groups did not any significant difference. Same cells injection was done with LLC-OVA-Mig and LLC-OVA-IKKβ. Compared to LLC-OVA-Mig, LLC-OVA-IKKβ tumors grew initially but were subsequently rejected. Importantly, a similar percentage of activated OVA-specific CD8T cells were detected in peripheral blood of mice receiving LLC-OVA-Mig and LLC-OVA-IKKβ, suggesting that the reduced growth of LLC-OVA-IKKβ tumor was not due to impaired T cells priming. Interestingly, more tumor infiltrating CD8+T cells were detected in LLC-OVA-IKKβ tumors. Using a metastatic LLC model, LLC-OVA-IKKβ showed substantially fewer and smaller lung tumor foci than LLC-OVA-Mig. However, LLC-OVA-IKKP grew robustly in Rag2-/-mice, demonstrating a role of lymphocytes, and more specifically, T cells, in immune rejection of LLC-OVA-IKKβ. To investigate the mechanism underlying the T cells recruitment and tumor rejection, gene profile of LLC-OVA-Mig and LLC-OVA-IKKP was analyzed by microarray, finding CCL2was upregulated in LLC-OVA-IKKβ cells which was reassured by Real time PCR and ELISA. CCL2knock down in LLC-OVA-IKKβ resulted in robust tumor growth while control LLC-OVA-IKKβ tumors were readily rejected. All the above data showed the tumor infiltrating CD8+T cells recruimented mainly by CCL2plays critical role in tumor rejection.Charpter3. Adenovirus vectors encoding constituvately activated NIK, IRF3, IKKa and IKKβ were constructed. Firstly the expressions of interest genes were verified by western blot and the downstream genes expression. Then Balb/c mice were subcutaneously immunized with PBS, AdGFP, AdNIK, AdIRF3, AdIKKα or AdIKKβ. To our surprise, the cellular immune response was only enhanced in AdIKK β grouop and lasted for a short time. Subsequently, intratumoral injection of AdIRF3was tested. Tubo tumors injected with AdIRF3showed more tumor infiltrating CD8+T and CD4+T cells as well as slowly tumor growth. But there is no difference of tumor infiltrating Treg among groups. Moreover, T cells from AdIRF3group also showed enhanced immne response demonstrated by Elispot.Overall, we can conclude IKKβ could activate the NF-kB signaling pathway and induce the elevated expression of CCL2which could recruit the T cells into tumor microenvironment, resulting in the tumor rejection. Intratumoral injection of AdIRF3also could enrich the lymphocytes into tumor environment and enhance the antigen-specific T cells to slow the tumor growth.