Ago2 Induces Kras Signaling And Promotes Tumor Progression In Mouse Models Of Lung Adenocarcinoma.

Abstract 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 multiple cell lines, AGO2 knockdown reduces KRAS protein level and attenuates cell proliferation. We therefore hypothesized that AGO2 could promote KRASG12D-dependent NSCLC in vivo. To test the hypothesis, we evaluated the impact of Ago2 knockout in the KPC mouse model of NSCLC. In KPC mice, intratracheal delivery of adenoviral Cre drives lung-specific expression of a stop-floxed KRASG12D allele and biallelic ablation of p53. Simultaneous biallelic ablation of floxed Ago2 inhibited KPC lung nodule growth while reducing proliferative index and improving pathological grade. We next applied the KPHetC model, in which the clara cell-specific CCSP-driven Cre activates KRASG12D and ablates a single p53 allele. In these mice, Ago2 ablation also reduced tumor size and grade. In both models, Ago2 knockout inhibited ERK phosphorylation in tumor nodules, indicating impaired KRAS signaling. Furthermore, RNA-seq analysis of KPC nodules demonstrated broadly reduced expression of Kras-related genes. Taken together, our data demonstrate a novel pathogenic role for AGO2 in KRAS-dependent NSCLC. Given the prevalence of this malignancy and current difficulties in therapeutically targeting KRAS signaling, our work has future translational relevance. Citation Format: Jean C. Tien, Seema Chugh, Andrew E. Goodrum, Yunhui Cheng, Lisha Wang, Rahul Mannan, Xiaoming Wang, Vijaya L. Dommeti, Yuping Zhang, Alice Xu, Fengyu Su, Xuhong Cao, Sunita Shankar, Arul M. Chinnaiyan. Ago2 induces Kras signaling and promotes tumor progression in mouse models of lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2936.