Discovery of Novel LRPPRC Inhibitors Featuring a Biphenyl-Acylhydrazone Scaffold with Potent Broad-Spectrum Antitumor Activity.

Abstract

Leucine-rich pentatricopeptide repeat containing (LRPPRC), a critical regulator of mitochondrial gene expression, is overexpressed in various malignancies and sustains oxidative phosphorylation (OXPHOS)-dependent adenosine triphosphate (ATP) production essential for tumor growth, chemoresistance, and stem cell survival, rendering it a promising therapeutic target. Herein, using an aptamer-assisted fluorescence polarization platform, we identified acylhydrazone-skeleton inhibitors targeting LRPPRC's RNA-binding domain, leading to the design and synthesis of over 60 derivatives. Lead compound 3o exhibited excellent LRPPRC inhibitory activity (92% at 6.25 μM vs 38% for gossypol acetate (GAA)) and induced robust LRPPRC degradation. Notably, 3o downregulated downstream OXPHOS subunits and ATP synthase, eliciting broad antiproliferative effects, particularly in refractory and drug-resistant A549, BXPC-3, and NCI-H1975 cells (IC50 = 0.54, 0.27, and 1.39 μM, respectively). In PC9 and HCT116 xenografts, 3o achieved tumor growth inhibition (TGI) rates of 73 and 49% with favorable safety profiles. Overall, we developed novel biphenyl-acylhydrazone LRPPRC inhibitors as potent antitumor agents acting via OXPHOS modulation, providing a valuable lead compound for cancer therapy.