Tylophorine Analogs Allosterically Regulates Heat Shock Cognate Protein 70 And Inhibits Hepatitis C Virus Replication

Abstract

Tylophorine analogs have been shown to exhibit diverse activities against cancer, inflammation, arthritis, and lupus in vivo. In this study, we demonstrated that two tylophorine analogs, DCB-3503 and rac-cryptopleurine, exhibit potent inhibitory activity against hepatitis C virus (HCV) replication in genotype 1b Con 1 isolate. The inhibition of HCV replication is at least partially mediated through cellular heat shock cognate protein 70 (Hsc70). Hsc70 associates with the HCV replication complex by primarily binding to the poly U/UC motifs in HCV RNA. The interaction of DCB-3503 and rac-cryptopleurine with Hsc70 promotes the ATP hydrolysis activity of Hsc70 in the presence of the 3′ poly U/UC motif of HCV RNA. Regulating the ATPase activity of Hsc70 may be one of the mechanisms by which tylophorine analogs inhibit HCV replication. This study demonstrates the novel anti-HCV activity of tylophorine analogs. Our results also highlight the importance of Hsc70 in HCV replication.

Structure-activity relationships of cryptopleurine analogs with E-ring modifications as anti-hepatitis C virus agents

“…22 Hsc70 co-localized with HCV particles in lipid droplet in the infected cells. 14 Hsc70 is also a major chaperone protein participating in the assembly of several subcellular complexes, for example HCV replication complex 6 and RNA-induced silencing complex. 23 The chaperone function of Hsc70 is governed by the N-terminal nucleotide binding domain (NBD) with ATPase activity.…”

“…25,26 By promoting the ATPase activity of Hsc70, rac-cryptopleurine and DCB-3503 inhibited HCV. 6,26 Thus, we next determined the impact of cryptopleurine analogs on the ATP/ADP turnover of Hsc70. Addition of rac-cryptopleurine enhanced ADP production by promoting the ATPase activity of Hsc70 at 10 mM (Fig.…”

“…5 Our previous study suggested that heat shock cognate protein 70 (Hsc70) binds to the 3 0 untranslated region (NTR) and is involved actively in HCV replication. 6 Allosteric regulation of the ATPase activity of Hsc70 by tylophorine analogs DCB-3503 and rac-cryptopleurine perturbed translation of HCV RNA, which lead to inhibition of HCV replication. 6 rac-Cryptopleurine analogs exhibited inhibitory activities against several diseases, including cancer, 7,8 arthritis, 9 inflammation, 10 and dysentery.…”

“…6 Allosteric regulation of the ATPase activity of Hsc70 by tylophorine analogs DCB-3503 and rac-cryptopleurine perturbed translation of HCV RNA, which lead to inhibition of HCV replication. 6 rac-Cryptopleurine analogs exhibited inhibitory activities against several diseases, including cancer, 7,8 arthritis, 9 inflammation, 10 and dysentery. 11 We designed and synthesized a series of E-ring modified rac-cryptopleurine analogs, 7,10 which showed improved anti-cancer activity than the parent compounds.…”

“…replication complex, especially the binding between NS5A, NS5B, HCV RNA, and heat shock cognate protein 70 (Hsc70). 6 Despite the potency rac-cryptopleurine exhibited, the selection index of this compound to HCV replication and cytotoxicity is low (IC 50 / EC 50 is only <4 fold, Table 1). Modification of the E-ring of rac-cryptopleurine also changed the potency and inhibitory effect on NF-jB, AP-1, and CRE signaling pathways.…”