AR-12 Inhibits Multiple Chaperones Concomitant With Stimulating Autophagosome Formation Collectively Preventing Virus Replication

Abstract

We have recently demonstrated that AR-12 (OSU-03012) reduces the function and ATPase activities of multiple HSP90 and HSP70 family chaperones. Combined knock down of chaperones or AR-12 treatment acted to reduce the expression of virus receptors and essential glucosidase proteins. Combined knock down of chaperones or AR-12 treatment inactivated mTOR and elevated ATG13 S318 phosphorylation concomitant with inducing an endoplasmic reticulum stress response that in an eIF2α—dependent fashion increased Beclin1 and LC3 expression and autophagosome formation. Over-expression of chaperones prevented the reduction in receptor/glucosidase expression, mTOR inactivation, the ER stress response, and autophagosome formation. AR-12 reduced the reproduction of viruses including Mumps, Influenza, Measles, Junín, Rubella, HIV (wild type and protease resistant), and Ebola, an effect replicated by knock down of multiple chaperone proteins. AR-12—stimulated the co-localization of Influenza, EBV and HIV virus proteins with LC3 in autophagosomes and reduced viral protein association with the chaperones HSP90, HSP70, and GRP78. Knock down of Beclin1 suppressed drug-induced autophagosome formation and reduced the anti-viral protection afforded by AR-12. In an animal model of hemorrhagic fever virus, a transient exposure of animals to low doses of AR-12 doubled animal survival from ∼30% to ∼60% and suppressed liver damage as measured by ATL, GGT and LDH release. Thus through inhibition of chaperone protein functions; reducing the production, stability and processing of viral proteins; and stimulating autophagosome formation/viral protein degradation, AR-12 acts as a broad-specificity anti-viral drug in vitro and in vivo. We argue future patient studies with AR-12 are warranted. J. Cell. Physiol. 231: 2286–2302, 2016. © 2016 Wiley Periodicals, Inc.