WEE1 Inhibitor AZD1775 Induces Anti-tumor Immunity By Activating ERV And The DsRNA Pathway

Objective:The strategy of combining targeted therapy with immunotherapy promises good perspective in cancer treatment.WEE1 kinase is a key regulator of the G2/M checkpoint in cell cycle.Recent studies have shown that WEE1 inhibitors have great potential in the treatment of tumors,but their impact on immune responses and the effectiveness of combination immunotherapy are still unclear.Therefore,the purpose of this study was to explore the effect of WEE1 inhibitors on immune responses,evaluate the effectiveness of their combined immunotherapy,and explore their potential application value in anti-tumor therapy.Methods:In this study,we preliminarily confirmed the effect of WEE1 inhibitor AZD1775on the interferon pathway and immune response based on database analysis and cell model validation.Second,by comparing the efficacy of AZD1775 in immune-competent and deficient mouse tumor-bearing models to further determine that AZD1775 exerts anti-tumor effects by regulating immunity.Then through whole genome sequencing,RNA-seq,Western blot,q PCR,immunofluorescence staining,ELISA,flow cytometry,immunohistochemical staining and other experimental methods to explore the specific regulatory mechanism of AZD1775-activated immune response.Finally,by establishing ID8,MC38,CT26 and B16 cell xenograft mouse models,we explored the efficacy of AZD1775 combined with immune checkpoint blockade in vivo and verified the specific mechanism of AZD1775 on immune regulation,thus summarizing effective biomarkers of AZD1775 sensitivity.Results:The results of this study indicated that the WEE1 inhibitor AZD1775 can activate the interferon pathway and immune response and exert anti-tumor effects through immune regulation.Mechanistically,AZD1775 down-regulated the expression of SETDB1/H3K9me3 by inhibiting the transcription factor FOXM1,thereby releasing the methylation inhibition of endogenous retroviral elements(ERVs)to produce large amounts of dsRNA,resulting in a"viral-like response"in the tumor.Second,in multiple tumor models with functional MAVS/DDX58 sensors,ERVs triggered dsRNA stress,which in turn activated the interferon(IFN)pathway and promotes the expression of interferon-stimulated genes(ISGs).More importantly,AZD1775 increased the recruitment of antitumor T cells while promoting PD-L1 expression on tumor cells.Compared with monotherapy,the combination of WEE1 inhibition and PD-L1 blockade showed the best efficacy in ID8 and MC38 xenograft models and exhibited a CD8~+T cell-dependent inhibition of tumor growth.Interestingly,however,in CT26 and B16 cells and xenograft models,due to their low expression levels of MAVS/DDX58 sensors and insignificant immune responses,they were insensitive to AZD1775-mediated antitumor effects and showed low response to combination therapy.Finally,the basal expression levels of SETDB1/FOXM1 and ISGs were summarized as effective molecular markers for AZD1775sensitivity.Conclusion:The WEE1 inhibitor AZD1775 activates the interferon response by regulating ERV/dsRNA,thereby enhancing antitumor efficacy,especially in combination with PD-L1blockers,which is a common feature of multiple types of tumors with robust MAVS/DDX58 function,suggesting that an available phenotype.AZD1775 promotes the recruitment of cytotoxic T cells and the expression of PD-L1 in tumor cells,which provides a theoretical basis for combined immune checkpoint blockade(ICB)therapy and clinical trials.