Purpose: Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide due to limited availability of effective therapeutic options. For instance, there are no effective strategies for NSCLCs that harbor mutant KRAS, the most commonly mutated oncogene in NSCLC. Thus, our purpose was to make progress toward the generation of a novel therapeutic strategy for NSCLC. Experimental Design: we characterized the effects of suppressing focal adhesion kinase (FAK) by RNA interference (RNAi), CRISPR/CAS9 gene editing or pharmacologic approaches in NSCLC cells and in tumor xenografts. In addition, we tested the effects of suppressing FAK in association with ionizing radiations, a standard of care treatment modality. Results: FAK is a critical requirement of mutant KRAS NSCLC cells. With functional experiments, we also found that, in mutant KRAS NSCLC cells, FAK inhibition resulted in persistent DNA damage and susceptibility to exposure to ionizing radiation (IR). Accordingly, administration of IR to FAK null tumor xenografts causes a profound antitumor effect in vivo. Conclusions: FAK is a novel regulator of DNA damage repair in mutant KRAS NSCLC and its pharmacologic inhibition leads to radiosensitizing effects that could be beneficial in cancer therapy. Our results provide a framework for the rationale clinical testing of FAK inhibitors in NSCLC patients.
- Received October 26, 2015.
- Revision received March 29, 2016.
- Accepted May 8, 2016.
- Copyright ©2016, American Association for Cancer Research.