Abstract 5099: Evaluating Ago2 as an oncogene in Kras-dependent lung carcinoma

Abstract

Abstract Background: Lung cancer is the deadliest malignancy in the United States. Non-small cell lung cancer (NSCLC) accounts for 85% of cases, and is frequently driven by activating mutations in the gene encoding the KRAS GTPase (e.g. KRASG12D). Our previous work demonstrated that Argonaute 2 (AGO2)—a component of the RNA induced silencing complex (RISC)—physically interacts with KRAS and stabilizes it at the protein level. In NSCLC cell lines, AGO2 knockdown reduces KRAS protein level and attenuates cell proliferation. We hypothesized that AGO2 acts as an oncogene in KRASG12D-dependent NSCLC in vivo. Methods: To test the hypothesis, we generated a NSCLC model by intercrossing mice harboring a stop-floxed KRASG12D allele with animals containing a tamoxifen-responsive Cre recombinase gene driven by the (clara cell-specific) CCSP promoter. These animals, which frequently die within 10 weeks of tamoxifen treatment, display pulmonary lesions including hyperplasia, adenoma and frank adenocarcinoma. We evaluated whether concomitant ablation of one or both copies of (floxed) AGO2 influenced the NSCLC phenotype. After tamoxifen administration, we monitored mice daily and harvested tissues when mice were clinically moribund or reached 16 weeks of post-treatment. We harvested lungs for gross/ pathological examination and gene/ protein expression analysis. Results: While pathologically discernable adenocarcinoma was detectable in AGO2+/+ and AGO2f/+ animals, AGO2f/f mice were free of these lesions. Despite this, deletion of AGO2 had no impact on frequency or extent of hyperplastic or adenomatous lesions. Immunohistochemistry demonstrated absence of AGO2 in tumor tissue of AGO2f/f mice. Conclusion: AGO2 promotes progression but not initiation of cancerous lesions in a mouse model of KRASG12D-dependent NSCLC. Citation Format: Andrew E. Goodrum, Lisha Wang, Alice Xu, Kristin M. Juckette, Arul M. Chinnaiyan, Jean C. Tien. Evaluating Ago2 as an oncogene in Kras-dependent lung carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5099.