br A br B br viability br Cell

A
B
viability
Cell 20 HFF
Migrated cells (% of control) 
DMSO
viability 40
Cell
Invaded cells (% of control) 
Cortactin
F-actin
Merge
anti-metastatic therapeutics through the structural modification of Benp. In conclusion, Benp will be a good molecular probe for a better understanding of the cellular functions of the Arp2/3 complex and cell migration. Benp is also a valuable tool to study the role of K 252a cy-toskeleton in various cellular processes [48]. ARPC2 might be a po-tential target for anti-metastatic therapy, and Benp is a potential can-didate for developing anti-metastatic agents. 
Conflicts of interest
The authors declare that there are no competing financial interests.
Acknowledgements
This work was supported by the KRIBB Research Initiative Program, the Bio-Synergy Research Project, and the Bio & Medical Technology Development Program of the National Research Foundation & funded
References
Contents lists available at ScienceDirect
Phytomedicine
journal homepage: www.elsevier.com/locate/phymed
Original Article
Benzoquinones from Cyperus spp. trigger IRE1α-independent and PERK-dependent ER stress in human stomach cancer cells and are novel proteasome inhibitors 
T
Vera Ribeiro, Paula B. Andrade, Patrícia Valentão, David M. Pereira
REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, R. Jorge Viterbo Ferreira, nº 228, 4050-313 Porto, Portugal
Keywords:
Cyperus spp.
Benzoquinones
Cancer
Endoplasmic reticulum
Regulated cell death
Proteasome inhibitors 
Background: The roots and tubers of several species of the Cyperus genus are used in several parts of the world as foodstuffs and beverages. The genus is rich in several classes of quinones, however their biological properties have not been studied before. Purpose: We evaluated the anticancer effect of several benzoquinones isolated from the genus and described their mechanism of action towards cancer cells.
Methods: The most potent molecules were selected according to their effect upon cell viability. The mechanism of cell death was studied by using pharmacological inhibitors of caspases, caspase-3/4/9 activity assays, an-nexin-V/7-AAD by flow cytometry and intracellular reactive oxygen species and calcium levels through fluor-escence spectroscopy. Elucidation of the involvement of distinct branches of the ER stress pathway was pursued by RT-PCR and WB for mRNA and protein expression levels, respectively, as well as pharmacological inhibitors. Proteasome inhibitory activity was assessed by using purified 20S catalytic subunit with the fluorogenic sub-strate Suc-Leu-Leu-Val-Tyr-AMC.
Results: Cytotoxicity studies against cancer cell lines showed that the human gastric cancer cell line AGS was the most susceptible, the most potent molecule, hydroxycyperaquinone, exhibiting an IC50 close to 1 µM. Morphological and biochemical traits suggested that a process of regulated cell death was taking place, which was shown to be intrinsic pathway-independent. Results indicated that benzoquinones exert their toxicity by triggering ER stress, as shown by increased expression of CHOP (mRNA and protein levels), intracellular reactive oxygen species, changes in calcium dynamics and caspase-4 activation. Proteasome inhibition by these mole-cules is described for the first time.
Conclusion: Hydroxycyperaquinone is a novel sub-micromolar inhibitor of the 20S catalytic core of the 26S proteasome, causing cell death via IRE1α-independent/PERK-dependent pathways in stomach cancer cells. Its presence in products consumed orally may be of relevance for gastric tumors.