Over-expression of p27kip1 induces growth arrest and apoptosis mediated by changes of pRb expression in lung cancer cell lines.
p27kip1 is a cyclin-dependent kinase inhibitor which controls the G1 phase of the cell cycle in conjunction with pRb. p27 has been associated with cell-cycle arrest and apoptosis. In this study, we transferred the full-length human p27 cDNA using a replication-deficient recombinant adenoviral vector (Ax-p27) into lung cancer cell lines and evaluated the potential of this strategy for anti-cancer gene therapy. After infection with Ax-p27, the growth of H322, A549 and SQ-5 cells, which express pRb, was almost completely suppressed, though no such effect was found in H69 and Lu-135 cells, which do not express pRb. In addition, cell death from day 4 after infection with Ax-p27 was observed only in H322, A549 and SQ-5 cells but not in H69 and Lu-135 cells. The cell cycle of H322 cells treated with Ax-p27 became arrested at the G1 phase from day 1 to day 3 despite continued over-expression of p27. When we examined the changes in expression level of pRb and E2F-1, which play important roles in cell-cycle progression from G1 to S phase, down-regulation of pRb expression was detected in H322 cells 3 days after infection with Ax-p27. These data suggest that (i) the growth-inhibitory effect and induction of apoptosis by over-expression of p27 require expression of pRb and (ii) adenovirus-mediated p27 gene transfer may have promise as a novel strategy in cancer gene therapy.
Naruse
I
I
First Department of Internal Medicine, Gunma University School of Medicine, Maebashi, Japan.
Hoshino
H
H
Dobashi
K
K
Minato
K
K
Saito
R
R
Mori
M
M
D017209:Apoptosis; D015153:Blotting, Western; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002455:Cell Division; D050760:Cyclin-Dependent Kinase Inhibitor p27; D005434:Flow Cytometry; D006801:Humans; D020287:In Situ Nick-End Labeling; D008175:Lung Neoplasms / Q000473:pathology*; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000502:physiology*; D016160:Retinoblastoma Protein / Q000032:analysis / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D016160:Retinoblastoma Protein; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27