The Depside Derivative Pericodepside Inhibits Cancer Cell Metastasis and Proliferation by Suppressing Epithelial–Mesenchymal Transition

A depside derivative, named pericodepside ( 2 ), along with the known depside proatranorin III ( 1 ), was isolated from the solid cultivation of an Ascochyta rabiei strain that heterologously expresses atr1 and atr2 that are involved in the biosynthesis of atranorin in a fruticose lichen, Stereocaulon alpinum. The structure of 2 was determined by 1D and 2D NMR and MS spectroscopic data. The structure of 2 consisted of a depside–pericosine conjugate, with the depside moiety being identical to that found in 1 , suggesting that 1 acted as an intermediate during the formation of 2 through the esterification process. Pericodepside ( 2 ) strongly suppressed cell invasion and proliferation by inhibiting epithelial–mesenchymal transition and the transcriptional activities of β-catenin, STAT, and NF-κB in U87 (glioma cancer), MCF-7 (breast cancer), and PC3 (prostate cancer) cell lines.