Diterpenoid Vinigrol specifically activates ATF4/DDIT3-mediated PERK arm of unfolded protein response to drive non-apoptotic death of breast cancer cells

Abstract

Vinigrol is a natural diterpenoid with unprecedented chemical structure, driving great efforts into its total synthesis in the past decades. Despite anti-hypertension and anti-clot ever reported, comprehensive investigations on bioactions and molecular mechanisms of Vinigrol are entirely missing. Here we firstly carried out a complete functional prediction of Vinigrol using a transcriptome-based strategy coupled with multiple bioinformatic analyses and identified "anti-cancer" as the most prominent biofunction ahead of anti-hypertension and anti-depression/psychosis. Broad cytotoxicity was subsequently confirmed on multiple cancer types. Further mechanistic investigation on several breast cancer cells revealed that its anti-cancer effect was mainly through activating PERK/eIF2α arm of unfolded protein response (UPR) and subsequent non-apoptotic cell death independent of caspase activities. The other two branches of UPR, IRE1α and ATF6, were functionally irrelevant to Vinigrol-induced cell death. Using CRISPR/Cas9-based gene activation, repression, and knockout systems, we identified the essential contribution of ATF4 and DDIT3, not ATF6, to the death process. This study unraveled a broad anti-cancer function of Vinigrol and its underlying targets and regulatory mechanisms. It paved the way for further inspection on the structure-efficacy relationship of the whole compound family, making them a novel cluster of PERK-specific stress activators for experimental and clinical uses.

Keywords: ATF4; Anti-cancer; Brefeldin A (BFA) (PubChem CID: 5287620); Cycloheximide (PubChem CID: 6197); DDIT3; Doxorubicin (PubChem CID: 31703); GSK2606414 (PubChem CID: 53469448); PERK; Trans-ISRIB (PubChem CID: 1011240); Unfolded protein response; Vinigrol; Vinigrol (PubChem CID: 5492644); zVAD-FMK (PubChem CID: 5497174).