Comparison of the effectiveness of adenovirus vectors expressing cyclin kinase inhibitors p16INK4A, p18INK4C, p19INK4D, p21(WAF1/CIP1) and p27KIP1 in inducing cell cycle arrest, apoptosis and inhibition of tumorigenicity.
Cell cycle regulatory proteins are important candidates for therapeutic tumour suppressors. Adenovirus vectors were constructed to overexpress cyclin kinase inhibitors p16INK4A, p18INK4C, p19INK4D, p21(WAF1/CIP1) and p27KIP1 under the control of the murine cytomegalovirus immediate early gene promoter. These vectors directed the efficient expression of each of the cyclin kinase inhibitors and induced growth arrest, inhibited DNA synthesis, and prevented phosphorylation of the retinoblastoma protein (pRb) in cell lines expressing functional pRb. In pRb-deficient cells, expression of the cyclin kinase inhibitors was not effective in inhibiting DNA replication or growth arrest. Interestingly, three of the cyclin kinase inhibitors, p16, p18 and p27 were found to induce apoptotic death in transduced HeLa and A549 cells. When the vectors were tested for their ability to inhibit tumorigenicity in a polyomavirus middle T antigen model of murine breast carcinoma, expression of the cyclin kinase inhibitors resulted in a delay in tumour formation that varied from several weeks for the p19 expressing vector to greater than 25 weeks for the p27 expressing vector. When tumours were injected directly with the adenovirus vectors expressing the cyclin kinase inhibitors, only treatment with the vector expressing p16 resulted in a delay in tumour growth.
Schreiber
M
M
Department of Biology, McMaster University, Hamilton, Ontario, Canada.
Muller
W J
WJ
Singh
G
G
Graham
F L
FL
D000230:Adenocarcinoma; D000260:Adenoviruses, Human; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D015197:Carcinogenicity Tests; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002455:Cell Division; D002461:Cell Line, Transformed; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000096:biosynthesis* / Q000235:genetics; D050763:Cyclin-Dependent Kinase Inhibitor p18; D050764:Cyclin-Dependent Kinase Inhibitor p19; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D016213:Cyclins / Q000096:biosynthesis* / Q000235:genetics; D004791:Enzyme Inhibitors; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D008325:Mammary Neoplasms, Experimental; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis* / Q000235:genetics; D010766:Phosphorylation; D016160:Retinoblastoma Protein / Q000378:metabolism; D019076:Transgenes; D025521:Tumor Suppressor Proteins
C493956:CDKN1A protein, human; C493971:CDKN2C protein, human; C493974:CDKN2D protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050763:Cyclin-Dependent Kinase Inhibitor p18; D050764:Cyclin-Dependent Kinase Inhibitor p19; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D008869:Microtubule-Associated Proteins; D016160:Retinoblastoma Protein; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases