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

Elife. 2023 Oct 25:12:e85862. doi: 10.7554/eLife.85862.

Abstract

Pancreatic cancer is the seventh leading cause of cancer-related death worldwide, and despite advancements in disease management, the 5 -year survival rate stands at only 12%. 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. We synthesized a novel pro-drug of triptolide, (E)-19-[(1'-benzoyloxy-1'-phenyl)-methylidene]-Triptolide (CK21), which was formulated into an emulsion for in vitro and in vivo testing in rats and mice, and used 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. Intravenous 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 hr and ~8,000 DEGs at 12 hr. Overall inhibition of general RNA transcription was observed, and Ingenuity pathway analysis together with functional cellular assays confirmed inhibition of the NF-κB 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. Thus, CK21 is a novel pro-drug of triptolide that exerts potent anti-proliferative effects on human pancreatic tumors by inhibiting the NF-κB pathway, leading ultimately to mitochondrial-mediated tumor cell apoptosis.

Keywords: apotosis; cancer biology; drug development; mouse; pancreatic cancer; triptolide.

Plain language summary

Pancreatic cancer is a major cause of cancer-related deaths worldwide, with only 12% of patients surviving for five years after diagnosis. Individuals generally experience few symptoms of the disease in the early stages and are often diagnosed once the cancer has already spread to other parts of the body. By this point, options for treatment are limited. A molecule known as triptolide has been shown to kill breast, lung, pancreatic and other types of cancer cells. However, triptolide is toxic to humans and other animals, making it unsuitable for use in patients. One way to make drugs safer without compromising their beneficial effects is to modify their molecular structure. By formulating triptolide into an emulsion – a mixture of liquids allowing it to dissolve – Tian, Zhang et al. synthesized a new analogue called CK21. Experiments showed that CK21 inhibited the growth of human pancreatic cancer cells grown in a laboratory including cells grown in artificial organs similar to the pancreas, known as pancreatic tumor organoids. Furthermore, CK21 killed large tumors in mice pancreases with very few side effects, suggesting the structural modification of triptolide increased safety of the drug. To better understand how CK21 works, Tian, Zhang et al. examined the genes that were induced in the pancreatic tumor organoids at various time points after treatment with the drug. This revealed that CK21 switched off genes involved in the NF-κB cell signaling pathway, which regulates how cells grow and respond to stress. In turn, it triggered programmed cell death, killing the tumor cells in a controlled manner. The findings suggest that CK21 could be a promising candidate for treating pancreatic cancer. In the future, clinical trials will be required to establish whether CK21 is a safe and effective therapy for humans.

MeSH terms

  • Animals
  • Antineoplastic Agents* / pharmacology
  • Antineoplastic Agents* / therapeutic use
  • Apoptosis
  • Cell Line, Tumor
  • Diterpenes* / pharmacology
  • Epoxy Compounds / pharmacology
  • Epoxy Compounds / therapeutic use
  • Humans
  • Mice
  • NF-kappa B / metabolism
  • Pancreatic Neoplasms* / pathology
  • Phenanthrenes*
  • Prodrugs* / pharmacology
  • Rats
  • Signal Transduction

Substances

  • NF-kappa B
  • triptolide
  • Diterpenes
  • Antineoplastic Agents
  • Epoxy Compounds
  • Prodrugs
  • Phenanthrenes

Associated data

  • GEO/GSE225011
  • Dryad/10.5061/dryad.dbrv15f7s

Grants and funding

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.