Neutrophil extracellular traps promote clear cell renal cell carcinoma progression via TGFβ1-pSmad2-MMP9 signaling

Clear cell renal cell carcinoma (ccRCC) exhibits high metastatic potential and a heavily infiltrated tumor immune microenvironment. Emerging evidence implicates neutrophil extracellular traps (NETs) in cancer progression, yet their functional role and mechanisms in ccRCC remain unclear. In this study, NETs were examined in ccRCC tissues and patient plasma by immunohistochemistry, immunofluorescence, and ELISA, and their effects on ccRCC proliferation, apoptosis, migration, and invasion were evaluated using in vitro and in vivo models. Mechanistic investigations involved RNA sequencing, database analysis, chromatin immunoprecipitation, luciferase reporter assays, and pharmacological interventions with DNase I and the MMP9 inhibitor JNJ-0966. NETs were found to be markedly elevated in ccRCC patients, especially those with metastases, and promoted tumor progression by enhancing proliferation, suppressing apoptosis, and facilitating migration and invasion. These effects were mediated through activation of the TGFβ1-pSmad2 pathway, which transcriptionally upregulated MMP9. Clinical analyses showed that high TGFβ1 and MMP9 expression correlated with poor survival. Importantly, NET degradation or MMP9 inhibition significantly reduced metastasis in vivo. Collectively, these findings identify NETs as key drivers of ccRCC progression via the TGFβ1-pSmad2-MMP9 axis and highlight NETs and MMP9 as potential therapeutic targets in advanced ccRCC.