Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal malignancies characterized by an intense tumor stroma with hypoperfused regions, a significant inflammatory response and pronounced therapy resistance. New therapeutic agents are urgently needed. The plant-derived agent triptolide also known as “thunder god vine” has a long history in traditional Chinese medicine for treatment of rheumatoid arthritis and cancer and is now in a clinical phase II trial for establishing the efficacy against a placebo. The authors mimicked the situation in patient tumors by induction of hypoxia in experimental models of pancreatic cancer stem cells (CSCs) and evaluated the therapeutic effect of triptolide. Hypoxia led to induction of colony and spheroid formation, aldehyde dehydrogenase 1 (ALDH1) and NF-κB activity, migratory potential and a switch in morphology to a fibroblastoid phenotype, as well as stem cell- and epithelial–mesenchymal transition-associated protein expression. Triptolide efficiently inhibited hypoxia-induced transcriptional signaling and downregulated epithelial–mesenchymal transition (EMT) and CSC features in established highly malignant cell lines, whereas sensitive cancer cells or nonmalignant cells were less affected. In vivo triptolide inhibited tumor take and tumor growth. In primary CSCs isolated from patient tumors, triptolide downregulated markers of CSCs, proliferation and mesenchymal cells along with upregulation of markers for apoptosis and epithelial cells. This study is the first to show that triptolide reverses EMT and CSC characteristics and therefore may be superior to current chemotherapeutics for treatment of PDA.What's new?Current treatment for pancreatic cancer does not directly target tumor hypoxia, a major mediator of aggressive growth, early metastasis, and therapy resistance. The plant-derived agent triptolide has a long history of use in rheumatoid arthritis and cancer in traditional Chinese medicine and has been shown to have potent therapeutic properties in a variety of studies. Here, the authors show for the first time that triptolide effectively inhibits hypoxia-induced signaling, leading to downregulation of NF-κB activity, epithelial-mesenchymal transition, and stem cell-like features. Triptolide may therefore be superior to current chemotherapeutics for treatment of pancreatic cancer.

No abstract

SummaryFertilized chicken eggs are employed as an alternative to mammalian models. The chorioallantoic membrane (CAM) of the chick embryo is widely used for examination of angiogenesis, xenotransplants and for virus production. Unfortunately, it is mostly not taken into account that the chick embryo's ability to experience pain starts to develop at day 7 of incubation. In our view, this model is only in accordance with the 3R principles if an appropriate anesthesia of the chick embryo in potentially painful procedures is provided. Although many experimental approaches are performed on the non-innervated CAM, the euthanasia of the embryo strongly requires a more humane technique than the commonly used methods of freezing at -20°C, decapitation or in ovo fixation with paraformaldehyde without prior anesthesia. However, protocols describing feasible and ethical methods for anesthesia and euthanasia of avian embryos are currently not available. Therefore, we established an easy and reliable method for the euthanasia and short-term anesthesia of the chick embryo.