WEE1 inhibition enhances the antitumor immune response to PD-L1 blockade by the concomitant activation of STING and STAT1 pathways in SCLC

Small cell lung cancers (SCLCs) have high mutational burden but are relatively unresponsive to immune checkpoint blockade (ICB). Using SCLC models, we demonstrate that inhibition of WEE1, a G2/M checkpoint regulator induced by DNA damage, activates the STING-TBK1-IRF3 pathway, which increases type I interferons (IFN-alpha and IFN-beta) and pro-inflammatory chemokines (CXCL10 and CCL5), facilitating an immune response via CD8 + cytotoxic T cell infiltration. We further show that WEE1 inhibition concomitantly activates the STAT1 pathway, increasing IFN-gamma and PD-L1 expression. Consistent with these findings, combined WEE1 inhibition (AZD1775) and PD-L1 blockade causes remarkable tumor regression, activation of type I and II interferon pathways, and infiltration of cytotoxic T cells in multiple immunocompetent SCLC genetically engineered mouse models, including an aggressive model with stabilized MYC. Our study demonstrates cell-autonomous and immune-stimulating activity of WEE1 inhibition in SCLC models. Combined inhibition of WEE1 plus PD-L1 blockade represents a promising immunotherapeutic approach in SCLC.

Automated summary

Inhibition of WEE1 in small cell lung cancer models activates the STING-TBK1-IRF3 pathway and increases type I interferons and pro-inflammatory chemokines, promoting an immune response. WEE1 inhibition also activates the STAT1 pathway and increases IFN-gamma and PD-L1 expression. Combined inhibition of WEE1 and PD-L1 leads to tumor regression and infiltration of cytotoxic T cells, indicating a promising immunotherapeutic approach.