Loss of LKB1 activity is prevalent in KRAS mutant
lung adenocarcinoma and promotes aggressive and treatment-resistant
tumors. Previous studies have shown that LKB1 is a negative regulator of the
focal adhesion kinase (FAK), but in vivo studies testing the efficacy of FAK inhibition in LKB1 mutant
cancers are lacking. Here, we took a pharmacologic approach to show that FAK inhibition is an effective early-treatment strategy for this high-risk molecular subtype. We established a lenti-Cre-induced Kras and Lkb1 mutant genetically engineered mouse model (KLLenti) that develops 100%
lung adenocarcinoma and showed that high spatiotemporal FAK activation occurs in collective invasive cells that are surrounded by high levels of
collagen. Modeling invasion in 3D, loss of Lkb1, but not p53, was sufficient to drive collective invasion and
collagen alignment that was highly sensitive to FAK inhibition. Treatment of early, stage-matched KLLenti
tumors with FAK inhibitor monotherapy resulted in a striking effect on
tumor progression, invasion, and
tumor-associated
collagen. Chronic treatment extended survival and impeded local lymph node spread. Lastly, we identified focally upregulated FAK and
collagen-associated collective invasion in KRAS and LKB1 comutated human
lung adenocarcinoma patients. Our results suggest that patients with LKB1 mutant
tumors should be stratified for early treatment with FAK inhibitors.