Penfluridol directly targets PDPK1 to suppress AKT1 phosphorylation and stabilize CTR1, inducing cuproptosis in colorectal cancer.

Abstract

Colorectal cancer (CRC) is a major cause of cancer mortality worldwide. Here, we identified the antipsychotic drug penfluridol as a potent anticancer agent that induces cuproptosis in CRC through a newly defined signaling mechanism. Using real-world clinical datasets, we demonstrated that PDPK1 is significantly upregulated in CRC and further increases in its expression level are correlated with a worse outcome, whereas CTR1 is downregulated in CRC and further decreases in its expression level are correlated with favourable outcomes, directly establishing the clinical relevance of these two proteins to CRC. Mechanistically, drug affinity responsive target stability assays revealed PDPK1 as a direct binding target of penfluridol. Penfluridol inhibited PDPK1 kinase activity and reduced AKT1 phosphorylation, which in turn decreased CTR1 ubiquitination and stabilized CTR1 on the plasma membrane. Enhanced CTR1 expression promoted intracellular copper influx, leading to copper overload and cuproptosis. Functionally, penfluridol suppressed CRC growth in cell lines, patient-derived organoids, and PDX models and was well-tolerated with limited systemic toxicity. Genetic and pharmacologic modulation confirmed that the PDPK1-p-AKT1-CTR1 axis governs copper homeostasis and mediates penfluridol-induced cell death. Collectively, our findings revealed a previously unrecognized link between oncogenic kinase signaling and copper metabolism, established PDPK1 and CTR1 as clinically relevant biomarkers, and provided a strong rationale for repurposing penfluridol as a dual-function therapeutic that induces cuproptosis and enhances chemosensitivity in colorectal cancer.