Evaluation of a Novel Pan-RAS Inhibitor in 3D Bioprinted Tumor Models

Background: Colorectal cancer (CRC) remains a significant global health burden, with KRAS mutations driving ~40% of cases. The efficacy of recently approved, mutant-specific KRAS inhibitors is limited by mutational status as well as intrinsic and adaptive resistance mechanisms. Pan-RAS inhibitors, such as ADT-007, offer broader therapeutic potential by targeting multiple RAS isoforms. Here, we evaluate ADT-007 in 3D bioprinted ex vivo slice tissue (BEST) generated from KRAS-mutant and RAS wild-type (WT) CRC cell lines. Methods: Potency and selectivity of ADT-007 were benchmarked against bortezomib (proteasome inhibitor) and YM155 (survivin inhibitor) using high-content imaging and ATP-based luminescence assays. Apoptosis induction was assessed with Annexin V/propidium iodide and flow cytometry. Results: ADT-007 exhibited high potency and selectivity in KRAS-mutant BEST, reducing tumor burdens >30% at nanomolar concentrations, and demonstrated superior selectivity with minimal cytotoxicity in WT RAS BEST. Annexin V staining confirmed selective induction of apoptosis in KRAS-mutant cells. Conclusions: The selective potency and specificity of ADT-007 warrant further investigation of pan-RAS inhibitors for treating RAS-driven cancers. This study also underscores the translational utility of 3D BEST models for preclinical drug response assessment. Further validation in patient-derived BEST is necessary to evaluate the potential of ADT-007 in clinical settings.