Targeted KRASG12V Degradation in vivo Elicits Lung Adenocarcinoma Regression with Subsequent Relapse from Dysregulated Proteolysis.

Recent drug discovery breakthroughs led to the approval of KRASG12C inhibitors in lung adenocarcinoma (LUAD). Unfortunately, clinical responses are often hampered by the rapid resistance onset. Proteolysis-targeting chimeras (PROTACs) have emerged as promising alternatives to traditional inhibition. However, there is limited mechanistic understanding of KRAS degradation in vivo. Here, we developed a preclinical LUAD mouse model and demonstrated that targeted oncogenic KRAS degradation induces rapid tumor regression primarily due to cancer cell-autonomous mechanisms. Yet, transcriptional, histological, and immunophenotypic analyses revealed a substantial remodeling of the tumor microenvironment. Notably, disease relapse observed during prolonged PROTAC treatment stemmed mostly from proteolysis machinery dysregulation, indicating resistance mechanisms distinct from those reported upon KRAS inhibition. Collectively, these findings highlight the therapeutic potential of KRAS degradation in LUAD, providing insights into both cell-intrinsic and -extrinsic mechanisms that accompany antitumor responses and support the ongoing clinical exploration of this approach.