Synergistic Anti-Tumor Activity of LRPPRC Inhibition and Dasatinib Through Dual Oxidative Phosphorylation Disruption

Background/Objectives: Mitochondrial Oxidative Phosphorylation (OXPHOS) is a critical metabolic dependency in many cancers. Targeting OXPHOS through Leucine-Rich PPR Motif-Containing Protein (LRPPRC) degrader-mediated OXPHOS Complex Biogenesis Inhibition (OCBI) has demonstrated promising anti-tumor activity. However, rational combination strategies to enhance therapeutic efficacy remain undefined. This study aims to identify FDA-approved drugs that synergize with LRPPRC inhibition and elucidate the underlying mechanism. Methods: We conducted a high-throughput screen of 1376 FDA-approved compounds using LRPPRC isogenic cancer cell models to identify agents that synergize with LRPPRC degrader-based OCBI therapy. The synergistic effects of the candidate compound were validated in multiple cancer cell lines with either genetic ablation or pharmacological inhibition of LRPPRC. Mechanistic studies were performed to investigate the impact on OXPHOS gene expression from both nuclear and mitochondrial genomes. Results: The clinically approved multi-kinase inhibitor Dasatinib was identified as a robust synergistic candidate, exhibiting heightened sensitivity in cancer cells with either LRPPRC knockout or pharmacological inhibition. Mechanistically, Dasatinib selectively suppressed nuclear-encoded OXPHOS genes, whereas LRPPRC inhibition preferentially impaired mitochondrial DNA-encoded OXPHOS genes, resulting in a coordinated dual-genome blockade of OXPHOS. Conclusions: This study uncovers a previously unrecognized synergistic anti-tumor effect between LRPPRC inhibition and Dasatinib, mediated by complementary suppression of nuclear- and mitochondrial genome-encoded OXPHOS pathways. These findings provide a strong mechanistic and translational rationale for combination therapies targeting LRPPRC-high tumors.