Neutrophils recruited by NKX2-1 suppression via activation of CXCLs/CXCR2 axis promote lung adenocarcinoma progression

Background: Lung adenocarcinoma (LUAD) progression is dependent on the immune tumor microenvironment through paracrine signaling. Lineage-specific transcription NKX2-1 is a well-developed pathology marker to define LUAD with progressive impact in patients. However, the involvement of NKX2-1 in modeling the tumor immune microenvironment is still unclear. Here, we demonstrated that NKX2-1-low tumors expedite tumor progression in LUAD through increased tumor-promoting neutrophils. Method: Single-cell RNA sequencing and Visium in situ capturing profiling were used to characterize the infiltration of neutrophils in NKX2-1-low LUAD tumors at high resolution. Clinical relevance of NKX2-1 expression and disease status were evaluated by immunohistochemical analysis of LUAD tissue arrays and the overall survival analysis was performed by TCGA databases. qRT-PCR validated the level of CXC chemokines, and proinflammatory genes in LUAD cells, meanwhile chemokine array confirmed the secretion of chemokines. Mechanistically, ATAC-seq was used to confirm the modulatory role of NKX2-1 on the chromatin accessibility of CXC chemokine genes. Results: NKX2-1 downregulation was observed in high-grade LUAD with increased neutrophil recruitment and infiltration. NKX2-1 knockdown promoted the expression and secretion of CXCL1, CXCL2, CXCL3, and CXCL5 in LUAD cells. Mechanistically, ATAC-seq revealed the restrictive regulation of NKX2-1 on the promoters of CXCL1, CXCL2 and CXCL5. Single-cell RNA sequencing and Visium in situ capturing revealed the infiltrated neutrophil had strong cell-cell communication through the activation of CXCLs/CXCR2 signaling with increased tumor growth and vice versa when inhibited with CXCR2 antagonist SB225002. Conclusion: This study revealed that NKX2-1 negatively regulates the infiltration of tumor-promoting neutrophils by suppressing CXCLs/CXCR2-dependent mechanisms. Hence, targeting CXCR2 in NKX2-1-low tumors is a potential antitumor therapy that improves LUAD patient outcomes.