A novel triptolide analog downregulates NF-κB and induces mitochondrial apoptosis pathways in human pancreatic cancer

Abstract

BackgroundPancreatic cancer is the seventh leading cause of cancer-related death worldwide, and despite advancements in disease management, the 5-year survival rates stands at only 9%. Triptolides have potent anti-tumor activity against different types of cancers, including pancreatic cancer, however poor solubility and toxicity limit their translation into clinical use. MethodsWe synthesized a novel pro-drug of triptolide, (E)-19-[(1-benzoyloxy-1-phenyl)-methylidene]-Triptolide (CK21), and formulated into an emulsion for in vitro and in vivo testing in rats and mice, and using human pancreatic cancer cell lines and patient-derived pancreatic tumor organoids. A time-course transcriptomic profiling of tumor organoids treated with CK21 in vitro was conducted to define its mechanism of action, as well as transcriptomic profiling at a single time point post-CK21 administration in vivo. FindingsIntravenous administration of emulsified CK21 resulted in the stable release of triptolide, and potent anti-proliferative effects on human pancreatic cancer cell lines and patient-derived pancreatic tumor organoids in vitro, and with minimal toxicity in vivo. Time course transcriptomic profiling of tumor organoids treated with CK21 in vitro revealed <10 differentially expressed genes (DEGs) at 3 h and [~]8,000 DEGs at 12 h. Overall inhibition of general RNA transcription was observed, and Ingenuity pathway analysis together with functional cellular assays confirmed inhibition of the NF-{kappa}B pathway, increased oxidative phosphorylation and mitochondrial dysfunction, leading ultimately to increased reactive oxygen species (ROS) production, reduced B-cell-lymphoma protein 2 (BCL2) expression, and mitochondrial-mediated tumor cell apoptosis. InterpretationCK21 is a novel pro-drug of triptolide that exerts potent anti-proliferative effects on human pancreatic tumors by inhibiting the NF-{kappa}B pathway, leading ultimately to mitochondrial-mediated tumor cell apoptosis. FundingThe study of the anti-tumor efficacy of CK21 supported in part by a research grant from Cinkate Pharmaceutical Corp; the funders had no role in the study design, interpretation or decision to publish. Patient-derived pancreatic tumor organoids were a generous gift from the Organoid and Primary Culture Research Core at University of Chicago.