title: Withaferin A suppresses tumor promoter 12-O-tetradecanoylphorbol 13-acetate-induced decreases in isocitrate dehydrogenase 1 activity and mitochondrial function in skin epidermal JB6 cells.
abstract: Withaferin A (WA) is a bioactive compound derived from Withania somnifera. The antitumor activity of WA has been well studied in human cancer models; however, its chemopreventive potential is unclear. In the present study, we used the skin epidermal JB6 P+ cells, a well-established model for tumor promotion, and demonstrated that WA suppressed the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced cell transformation and cell proliferation. Interestingly, TPA inactivated isocitrate dehydrogenase 1 (IDH1), which was reversed by WA. Similar results were also observed in mouse skin tissue. Therefore, we focused on metabolism as the potential mechanism of action. We found that mitochondrial functions were downregulated by TPA treatment, as indicated by reduced mitochondrial membrane potential, complex I activity and mitochondrial respiration. However, all of these downregulations were inhibited by WA. In addition, we examined the levels of α-ketoglutarate, a product of IDH1, and WA blocked its reduction upon TPA treatment. Finally, we detected the lactate level as a glycolysis marker, and WA suppressed its elevation caused by tumor promoter treatment. Altogether, these results suggest that WA might exert its chemopreventive activity via inhibiting not only oncogenic activation, but also IDH1 inactivation and mitochondrial dysfunction in early tumorigenesis.
authors.affiliation: Department of Pharmacology, Toxicology and Neuroscience, LSU Health Sciences Center in Shreveport, Shreveport, LA, USA.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Li
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019069:Cell Respiration / Q000187:drug effects / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004817:Epidermis / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D005260:Female; D006019:Glycolysis / Q000187:drug effects / Q000235:genetics; D007521:Isocitrate Dehydrogenase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D007656:Ketoglutaric Acids / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000235:genetics; D051379:Mice; D008811:Mice, Inbred DBA; D008928:Mitochondria / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D054358:Withanolides / Q000494:pharmacology*
chemical_list: D007656:Ketoglutaric Acids; D054358:Withanolides; D019344:Lactic Acid; D007521:Isocitrate Dehydrogenase; C009684:withaferin A; D013755:Tetradecanoylphorbol Acetate