TET2-STAT3-CXCL5 nexus promotes neutrophil lipid transfer to fuel lung adeno-to-squamous transition.

Phenotypic plasticity is a rising cancer hallmark, and lung adeno-to-squamous transition (AST) triggered by LKB1 inactivation is significantly associated with drug resistance. Mechanistic insights into AST are urgently needed to identify therapeutic vulnerability in LKB1-deficient lung cancer. Here, we find that ten-eleven translocation (TET)-mediated DNA demethylation is elevated during AST in KrasLSL-G12D/+; Lkb1L/L (KL) mice, and knockout of individual Tet genes reveals that Tet2 is required for squamous transition. TET2 promotes neutrophil infiltration through STAT3-mediated CXCL5 expression. Targeting the STAT3-CXCL5 nexus effectively inhibits squamous transition through reducing neutrophil infiltration. Interestingly, tumor-infiltrating neutrophils are laden with triglycerides and can transfer the lipid to tumor cells to promote cell proliferation and squamous transition. Pharmacological inhibition of macropinocytosis dramatically inhibits neutrophil-to-cancer cell lipid transfer and blocks squamous transition. These data uncover an epigenetic mechanism orchestrating phenotypic plasticity through regulating immune microenvironment and metabolic communication, and identify therapeutic strategies to inhibit AST.