Adenovirus expressing mutant p27kip1 enhanced apoptosis and inhibited the growth of xenografted human breast cancer.
OBJECTIVE
To evaluate the anti-tumor effects of a novel adenovirus expressing mutant p27(kip1) (Adp27-mt), which consists of a mutation of Thr-187/Pro-188 to Met-187/Ile-188.


METHODS
Using the human breast cancer cell lines, MDA-MB-231, ZR-75-1, and MCF-7, we tested Adp27-mt for cell cycle assay, growth inhibition assay, and TdT-mediated dUTP-biotin nick end labeling in a human breast cancer-grafted severe combined immunodeficiency (SCID) mouse model.


RESULTS
The mutant p27(kip1) induced stronger apoptosis in the breast cancer cell lines than adenovirus expressing wild-type p27(kip1) (Adp27-wt). Adp27-mt inhibits cell growth significantly; being about 5- and 3.5-fold stronger for IC50 than Adp27-wt in the breast cancer cell lines, MDA-MD-231 and ZR-75-1, respectively. In the human breast cancer-grafted SCID mouse model, Adp27-mt induced tumor regression and antitumor effects significantly better than Adp27-wt. Furthermore, Adp27-mt mainly caused G2/M arrest in the cell cycle progression, whereas Adp27-wt mediated a G1/S arrest 48 h after infection.


CONCLUSIONS
The mutant p27(kip1) protein induced apoptosis, and inhibited cell growth more efficiently with stronger anti-tumor effects than wild-type p27(kip1). Thus, the recombinant adenovirus expressing mutant p27(kip1) could be useful in gene therapy against breast cancer.
Sasaki
Tsuyoshi
T
Division of Hepato-Biliary Pancreatic Surgery, Department of Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan.
Katayose
Yu
Y
Yamamoto
Kuniharu
K
Mizuma
Masamichi
M
Shiraso
Satoru
S
Yabuuchi
Shinichi
S
Oda
Akira
A
Rikiyama
Toshiki
T
Oikawa
Masaya
M
Onogawa
Toru
T
Suzuki
Masanori
M
Lee
Choon-Taek
CT
Unno
Michiaki
M
D000256:Adenoviridae / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002453:Cell Cycle; D045744:Cell Line, Tumor; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000096:biosynthesis / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D047468:Immunoprecipitation; D020287:In Situ Nick-End Labeling; D051379:Mice; D016513:Mice, SCID; D009154:Mutation; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental
C493961:Cdkn1b protein, mouse; D004273:DNA, Neoplasm; D050760:Cyclin-Dependent Kinase Inhibitor p27