Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanism...Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanisms of GSK3βprotein expression remain elusive.Methods:Co-immunoprecipitation and mass spectral assays were performed to identify molecules binding to GSK3β,and to characterize the interactions of GSK3β,heat shock protein 90(Hsp90),and co-chaperones.The role of PGK1 in Hsp90 chaperoning GSK3βwas evaluated by constructing 293T cells stably expressing different domains/mutants of Hsp90α,and by performing a series of binding assays with bacterially purified proteins and clinical specimens.The influences of Hsp90 inhibitors on breast cancer stem cell stemness were investigated by Western blot and mammosphere formation assays.Results:We showed that GSK3βwas a client protein of Hsp90.Hsp90,which did not directly bind to GSK3β,interacted with phosphoglycerate kinase 1 via its C-terminal domain,thereby facilitating the binding of GSK3βto Hsp90.GSK3β-bound PGK1 interacted with Hsp90 in the“closed”conformation and stabilized GSK3βexpression in an Hsp90 activity-dependent manner.The Hsp90 inhibitor,17-AAG,rather than HDN-1,disrupted the interaction between Hsp90 and PGK1,and reduced GSK3βexpression,resulting in significantly reduced inhibition ofβ-catenin expression,to maintain the stemness of breast cancer stem cells.Conclusions:Our findings identified a novel regulatory mechanism of GSK3βexpression involving metabolic enzyme PGK1-coupled Hsp90,and highlighted the potential for more effective cancer treatment by selecting Hsp90 inhibitors that do not affect PGK1-regulated GSK3βexpression.展开更多
Heat shock protein 90(Hsp90)is a highly conserved molecular chaperone that plays a vital role in the signal transduction of cancers.Hsp90 inhibitors are able to inhibit Hsp90 or the complex of Hsp90 and co-chaperones ...Heat shock protein 90(Hsp90)is a highly conserved molecular chaperone that plays a vital role in the signal transduction of cancers.Hsp90 inhibitors are able to inhibit Hsp90 or the complex of Hsp90 and co-chaperones resulting in the degradation of Hsp90-dependent client proteins through the ubiqui tina tion-proteasome pathway,thereby leading to the growth inhibition of tumor cells.This review will briefy discuss the molecular structure and biological function of Hsp90,and focus on a summary of recent progress in the development and testing of natural Hsp90 inhibitors and their different means by which they interact with Hsp90.展开更多
基金This work was supported by grants from the NSFC Shandong Joint Fund(Grant No.U1606403)the National Natural Science Foundation of China(Grant No.81673450)+4 种基金the State Key Program of the National Natural Science Foundation of China(Grant No.82030074)the NSFC-Shandong Joint Fund(Grant No.U1906212)the Qingdao National Laboratory for Marine Science and Technology(Grant No.2015ASKJ02)the National Science and Technology Major Project for Significant New Drugs Development(Grant No.2018ZX09735-004)the Shandong Provincial Natural Science Foundation(major basic research projects,Grant No.ZR2019ZD18).
文摘Objective:Glycogen synthase kinase-3β(GSK3β)has been recognized as a suppressor of Wnt/β-catenin signaling,which is critical for the stemness maintenance of breast cancer stem cells.However,the regulatory mechanisms of GSK3βprotein expression remain elusive.Methods:Co-immunoprecipitation and mass spectral assays were performed to identify molecules binding to GSK3β,and to characterize the interactions of GSK3β,heat shock protein 90(Hsp90),and co-chaperones.The role of PGK1 in Hsp90 chaperoning GSK3βwas evaluated by constructing 293T cells stably expressing different domains/mutants of Hsp90α,and by performing a series of binding assays with bacterially purified proteins and clinical specimens.The influences of Hsp90 inhibitors on breast cancer stem cell stemness were investigated by Western blot and mammosphere formation assays.Results:We showed that GSK3βwas a client protein of Hsp90.Hsp90,which did not directly bind to GSK3β,interacted with phosphoglycerate kinase 1 via its C-terminal domain,thereby facilitating the binding of GSK3βto Hsp90.GSK3β-bound PGK1 interacted with Hsp90 in the“closed”conformation and stabilized GSK3βexpression in an Hsp90 activity-dependent manner.The Hsp90 inhibitor,17-AAG,rather than HDN-1,disrupted the interaction between Hsp90 and PGK1,and reduced GSK3βexpression,resulting in significantly reduced inhibition ofβ-catenin expression,to maintain the stemness of breast cancer stem cells.Conclusions:Our findings identified a novel regulatory mechanism of GSK3βexpression involving metabolic enzyme PGK1-coupled Hsp90,and highlighted the potential for more effective cancer treatment by selecting Hsp90 inhibitors that do not affect PGK1-regulated GSK3βexpression.
基金This work was supported by National Science Foundation of China(90913020 and 30901847)Science and Technology Program of China(2012ZX09103-101-053)Science and Technology Star of Zhujiang of Guangzhou City(Dongmei Zhang).
文摘Heat shock protein 90(Hsp90)is a highly conserved molecular chaperone that plays a vital role in the signal transduction of cancers.Hsp90 inhibitors are able to inhibit Hsp90 or the complex of Hsp90 and co-chaperones resulting in the degradation of Hsp90-dependent client proteins through the ubiqui tina tion-proteasome pathway,thereby leading to the growth inhibition of tumor cells.This review will briefy discuss the molecular structure and biological function of Hsp90,and focus on a summary of recent progress in the development and testing of natural Hsp90 inhibitors and their different means by which they interact with Hsp90.
