N-WASP deficiency enhances oncogenic KRAS-mediated lung adenocarcinoma progression in mice

Oncogenic KRAS mutations drive 25-30% of western lung adenocarcinoma (LUAD) cases, however the mechanisms that restrain tumor progression remain poorly defined. N-Wiskott-Aldrich syndrome protein (N-WASP) regulates actin cytoskeleton dynamics and epithelial architecture, but its role in KRAS-driven lung tumorigenesis is unclear.

We generated a conditional N-WASP knockout in KRAS^G12D-driven lung adenocarcinoma mice (N-WASP^LKO/KRAS^G12D) using Sftpc-CreERT2, and assessed N-WASP knockdown A549 cells (A549^KD) in 3D culture for tumor burden, ERK signaling, transcriptomic changes, and E-cadherin expression.

Conditional deletion of N-WASP in type II alveolar cells (N-WASP^LKO) markedly increased tumor number and size in KRAS^G12D mice. The tumors isolated from these mice retained strong pro-surfactant protein C expression, confirming alveolar epithelial origin and predominantly adopted a solid growth pattern, indicative of disrupted epithelial organization. Mechanistically, N-WASP loss enhanced KRAS-driven ERK1/2 activation in lung tissue, consistent with increased mitogenic signaling. In A549 cells, N-WASP deficiency disrupted cytoskeletal architecture, promoted proliferation, and impaired cell-cell adhesion, recapitulating in vivo tumor phenotypes. A kinase inhibitor screen identified Rho-associated protein kinase (ROCK) activity as a driver of this hyperproliferative phenotype, with ROCK inhibition normalizing proliferation in N-WASP-deficient cells, linking elevated Rho/ROCK signaling to the increased ERK1/2 activation observed upon N-WASP loss. Transcriptomic profiling of N-WASP-deficient lungs revealed coordinated upregulation of genes regulating proliferation, cytoskeletal remodeling, and tumor-promoting pathways, alongside downregulation of epithelial differentiation and adhesion programs.

These results establish N-WASP as a critical suppressor of KRAS-driven lung adenocarcinoma, linking cytoskeletal integrity to oncogenic signaling and transcriptional regulation. Our findings highlight the interplay between actin dynamics, epithelial architecture, and KRAS signaling, suggesting that targeting N-WASP dependent pathways could modulate lung cancer aggressiveness and offer novel therapeutic opportunities.