6-methoxydihydroavicine, the alkaloid extracted from Macleaya cordata (Willd.) R. Br. (Papaveraceae), triggers RIPK1/Caspase-dependent cell death in pancreatic cancer cells through the disruption of oxaloacetic acid metabolism and accumulation of reactive oxygen species

Phytomedicine. 2022 Jul 20:102:154164. doi: 10.1016/j.phymed.2022.154164. Epub 2022 May 13.

Abstract

Background: Many extracts and purified alkaloids of M. cordata (Papaveraceae family) have been reported to display promising anti-tumor effects by inhibiting cancer cell growth and inducing apoptosis in many cancer types. However, no evidence currently exists for anti-pancreatic cancer activity of alkaloids extracted from M. cordata, including a novel alkaloid named 6‑methoxy dihydrosphingosine (6-Methoxydihydroavicine, 6-ME) derived from M. cordata fruits.

Purpose: The aim of this study was to investigate the anti-tumor effects of 6-ME on PC cells and the underlying mechanism.

Methods: CCK-8, RTCA, and colony-formation assays were used to analyze PC cell growth. Cell death ratios, changes in MMP and ROS levels were measured by flow cytometry within corresponding detection kits. A Seahorse XFe96 was employed to examine the effects of 6-ME on cellular bioenergetics. Western blot and q-RT-PCR were conducted to detect changes in target molecules.

Results: 6-ME effectively reduced the growth of PC cells and promoted PCD by activating RIPK1, caspases, and GSDME. Specifically, 6-ME treatment caused a disruption of OAA metabolism and increased ROS production, thereby affecting mitochondrial homeostasis and reducing aerobic glycolysis. These responses resulted in mitophagy and RIPK1-mediated cell death.

Conclusion: 6-ME exhibited specific anti-tumor effects through interrupting OAA metabolic homeostasis to trigger ROS/RIPK1-dependent cell death and mitochondrial dysfunction, suggesting that 6-ME could be considered as a highly promising compound for PC intervention.

Keywords: 6-ME; OAA metabolism; PC intervention; PCD; RIPK1/caspases/GSDME; ROS.

MeSH terms

  • Alkaloids* / pharmacology
  • Antineoplastic Agents* / pharmacology
  • Caspases* / metabolism
  • Cell Death / drug effects
  • Equol / analogs & derivatives*
  • Equol / pharmacology
  • Humans
  • Oxaloacetic Acid* / metabolism
  • Pancreatic Neoplasms* / drug therapy
  • Pancreatic Neoplasms* / metabolism
  • Pancreatic Neoplasms* / pathology
  • Papaveraceae / chemistry
  • Reactive Oxygen Species* / metabolism
  • Receptor-Interacting Protein Serine-Threonine Kinases* / metabolism

Substances

  • 6-methoxyequol
  • Alkaloids
  • Antineoplastic Agents
  • Reactive Oxygen Species
  • Oxaloacetic Acid
  • Equol
  • RIPK1 protein, human
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Caspases