Targeting adhesion signaling in KRAS, LKB1 mutant lung adenocarcinoma
Melissa Gilbert-Ross, … , Wei Zhou, Adam I. Marcus
Melissa Gilbert-Ross, … , Wei Zhou, Adam I. Marcus
Published March 9, 2017
Citation Information: JCI Insight. 2017;2(5):e90487. https://doi.org/10.1172/jci.insight.90487.
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Research Article Cell biology Oncology

Targeting adhesion signaling in KRAS, LKB1 mutant lung adenocarcinoma

Abstract

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.

Authors

Melissa Gilbert-Ross, Jessica Konen, Junghui Koo, John Shupe, Brian S. Robinson, Walter Guy Wiles IV, Chunzi Huang, W. David Martin, Madhusmita Behera, Geoffrey H. Smith, Charles E. Hill, Michael R. Rossi, Gabriel L. Sica, Manali Rupji, Zhengjia Chen, Jeanne Kowalski, Andrea L. Kasinski, Suresh S. Ramalingam, Haian Fu, Fadlo R. Khuri, Wei Zhou, Adam I. Marcus

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Figure 1

A lenti-Cre KrasG12DLkb1fl/fl mouse model (KLLenti) of lung adenocarcinoma reveals high levels of active FAK in collagen-associated collective invasion packs (CIPs) in vivo.

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A lenti-Cre KrasG12DLkb1fl/fl mouse model (KLLenti) of lung adenocarcino...
(A) Lenti-Cre model of KrasG12D Lkb1fl/fl lung adenocarcinoma. White arrows indicate primary lung tumors. Scale bar: 50 mm. (B) Double immunofluorescence analysis of pYFAK397/E-Cad (left column), E-Cad/SP-C (middle column), and E-Cad/CCSP (right column) from serial sections of late-stage KLLenti invasive primary tumors. Arrows mark CIPs, and arrowheads are located behind the invasive front. Scale bars: 100 μm. (C) Representative images of IHC of pYFAK397 and serial H&E-stained sections from KLLenti adenocarcinoma in situ (AIS) (top) and invasive adenocarcinoma (Inv Adc) (bottom) (n = 6). Black arrows mark pYFAK-positive invasive tumor cells, and arrowheads are located behind the invasive front. Scale bars: 200 μm. v, vessel. (D) SHG (white; top row) imaging of collagen in KLLenti Inv Adc compared with a normal bronchovascular bundle and AIS. Cell structure is visualized by H&E autofluorescence (pseudo-colored blue). Scale bar: 50 μm. Yellow dashed boxes outline regions merged and magnified in inset. Scale bar: 50 μm. Red arrows mark CIPs, and yellow arrow marks direction of invasive front. (E) Quantitation of collagen density by mean SHG signal intensity from lung tumor sections of the indicated genotype and stage (n = 2 lung lobes each from 3 independent mice [KLLenti AIS and KLLenti Inv Adc], and n = 1–2 lung lobes from 6 independent mice [KP Inv Adc]). Data are represented as mean ± SD. P values were calculated using 1-way ANOVA with Tukey’s multiple comparisons test. ****P < 0.0001; **P < 0.01.