?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F8144%2F&rft.title=CELL-BASED+AND+BIOCHEMICAL+SCREENS+FOR+SMALL-MOLECULE+INHIBITORS+OF+DYNEIN+AND+OF+HSP70&rft.creator=Zhu%2C+Guangyu&rft.description=Dyneins+are+protein+motor+complexes+that+generate+force+towards+the+minus+ends+of+microtubules%2C+and+cytoplasmic+dynein+plays+a+variety+of+important+roles+in+cell.+A+small+library+of+synthetic+chemicals+based+on+the+nature+product+purealin+was+first+examined+for+inhibition+of+cytoplasmic+dynein+heavy+chain+and+cell+growth.+The+compounds+showed+effective+antiproliferative+activity+against+a+mouse+leukemia+cell+line%2C+but+selective+activities+against+a+small+panel+of+human+carcinoma+cell+lines.+Purealin+and+some+of+its+analogues+showed+concentration+dependent+inhibitory+effects+against+the+microtubule-stimulated+ATPase+activity+of+both+bovine+cytoplasmic+dynein+heavy+chain+as+well+as+the+recombinant+motor+domain+of+human+cytoplasmic+dynein+in+an+uncompetitive+pattern%2C+indicating+that+they+do+not+compete+with+the+binding+of+ATP.+Purealin+also+weakly+inhibited+p53+nuclear+accumulation+after+DNA+damage.+Treatment+of+cells+with+small+interfering+RNAs+of+cytoplasmic+dynein+heavy+chain+were+also+used+as+a+positive+control+in+this+assay%2C+although+the+lifetime+of+the+protein+turned+out+to+be+too+long+for+the+siRNA+approach+to+be+useful+in+a+screening+protocol.A+strategy+was+built+to+screen+for+dynein+inhibitors+based+on+a+GFP-GR+nuclear+translocation+assay+by+using+a+mouse+mammary+adenocarcinoma+cell+line+(3617.4)+stably+expressing+the+fluorescent+protein.+A+small+library+of+synthetic+compounds+was+screened+for+inhibition+of+hormone-stimulated+GFP-GR+nuclear+translocation.+Several+compounds+was+found+to+elicit+the+desired+phenotype%2C+and+these+compounds+inhibited+the+ATPase+activity+of+cytoplasmic+dynein+heavy+chain+motor+domain+without+competing+for+the+hydrolyzable+ATP-binding+site.+Biochemical+specificity+tests+showed+that+the+compounds+did+not+compete+for+GR+binding+nor+inhibit+the+ATPase+activities+of+Hsp70%2C+Hsp90+or+myosin.+Libraries+of+compounds+designed+to+be+Hsp70-perturbing+agents+were+also+evaluated.+Previous+data+showed+that+the+Hsp70+chaperone+class+is+induced+in+certain+breast+cancer+cells+and+that+antisense-mediated+knockdown+of+Hsp70+triggers+apoptosis%2C+indicating+that+Hsp70s+represent+a+new+target+for+breast+cancer+therapy.+A+small+molecule+inhibitor+of+Hsp70+co-chaperone+interaction+(MAL3-101)%2C+as+well+as+several+analogues%2C+showed+antiproliferative+activity+against+SK-BR3+breast+cancer+cells.&rft.date=2007-09-27&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F8144%2F1%2FDissertation-GZhu-062807.pdf&rft.identifier=++Zhu%2C+Guangyu++(2007)+CELL-BASED+AND+BIOCHEMICAL+SCREENS+FOR+SMALL-MOLECULE+INHIBITORS+OF+DYNEIN+AND+OF+HSP70.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++