Abstract 1582: Inhibition of autophagy by CAGE targeting peptide retard tumor growth in non-small cell lung cancer of EGFR TKI resistance

Abstract Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) is the standard of care as 1st-line treatment for NSCLC patients with activating EGFR mutations (exon 19 deletion or L858R mutation). However, EGFR-TKI therapy eventually leads to acquired drug resistance approximately 1-2 years from the beginning of treatment. Multiple acquired resistance mechanisms including on-target EGFR mutations, phenotype transformation, and activation of bypass signaling molecules have been identified, but over 35% still remains unknown. CAGE, a cancer/testis antigen, was originally isolated from the sera of patients with gastric cancer and is known to regulate the autophagic flux in acquired resistance to EGFR TKI in NSCLC. Herein, the expression of CAGE was found in more than 50% of NSCLC patients using immunohistochemistry (IHC). Interestingly, the expression level was increased especially for the patients acquiring resistance to EGFR-TKIs. In addition, both PC-9/ER (Erlotinib-resistance cells) and H1975/OR (Osimertinib-resistant cells) cells demonstrated increased CAGE expression and autophagic flux, when compared with their parental cells. Thus, we developed the peptide drugs targeting the DEAD box domain of CAGE. This novel peptide effectively inhibited tumor cell proliferation in EGFR-TKI resistant cell line. Moreover, in Erlotinib-resistant patient-derived xenograft (PDX) mice, the peptide drug retarded tumor growth and enhanced anti-tumor efficacy. Collectively, our data suggest that CAGE plays a crucial role in the tumor progression and acquired resistance of EGFR TKI by the modulation of autophagic flux. Furthermore, we provided evidence that the inhibition of autophagy through CAGE- derived peptide could overcome the acquired resistance to EGFR TKIs in advanced/metastatic NSCLC patients. Citation Format: Jung-Young Shin, Min-Young Kim, Mi-Ran Lee, Hankyu Lee, Doyong Jeon, Seung Ryel Baek, Kim Joo Il, Jaemoon Koh, Dooil Jeoung, Jin Hyoung Kang. Inhibition of autophagy by CAGE targeting peptide retard tumor growth in non-small cell lung cancer of EGFR TKI resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1582.