An adenovirus expressing mutant p27 showed more potent antitumor effects than adenovirus-p27 wild type.
The main inhibitory action of p27, a cyclin-dependent kinase inhibitor (CDKI), arises from its binding with the cyclin E/cyclin-dependent kinase 2 (Cdk2) complex that results in G(1)-S arrest. Degradation of p27 is mediated by phosphorylation of Thr-187 of p27, which follows ubiquitination. In this study, we generated two adenoviruses expressing wild-type p27 (ad-p27wt) and mutant p27 (ad-p27mt), with mutation of Thr-187/Pro-188 (ACGCCC) to Met-187/Ile-188 (ATGATC), which was produced with the belief that mutant p27 would bind cyclin E/CDK2 more stably and show more potent antitumor effects. Ad-p27wt and ad-p27mt expressed p27 proteins that were indistinguishable by anti-p27 antibody. A pulse chase experiment showed that p27mt was more resistant to degradation than p27wt. In human lung cancer cell lines, ad-p27mt showed stronger growth inhibition than ad-p27wt. Both types of ad-p27 induced G(1)-S arrest and apoptosis; however, ad-p27mt induced stronger G(1)-S arrest and apoptosis. Intratumoral injection of ad-p27mt induced partial regression of established tumors and inhibited the growth of human lung cancer xenografts more strongly than ad-p27wt. From these results, we conclude that ad-p27mt has the potential to become a novel and powerful gene therapy tool.
Park
K H
KH
Department of Internal Medicine, Seoul National University College of Medicine, Lung Institute of Medical Research Center, Seoul National University, Seoul 110-744, Korea.
Seol
J Y
JY
Kim
T Y
TY
Yoo
C G
CG
Kim
Y W
YW
Han
S K
SK
Shim
Y S
YS
Lee
C T
CT
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D042846:CDC2-CDC28 Kinases; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000473:pathology / Q000628:therapy; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D053938:DNA Fragmentation; D005260:Female; D005434:Flow Cytometry; D016193:G1 Phase / Q000502:physiology; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010766:Phosphorylation; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000378:metabolism; D016196:S Phase / Q000502:physiology; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins; D023041:Xenograft Model Antitumor Assays
C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D019927:Cyclin E; D016160:Retinoblastoma Protein; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D011065:Poly(ADP-ribose) Polymerases; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases