A single recombinant adenovirus expressing p53 and p21-targeting artificial microRNAs efficiently induces apoptosis in human cancer cells.
OBJECTIVE
Gene transfer involving p53 is viewed as a potentially effective cancer therapy, but does not result in a good therapeutic response in all human cancers. The activation of p53 induces either cell cycle arrest or apoptosis. Cell cycle arrest in response to p53 activation is mediated primarily through the induction of the cyclin-dependent kinase inhibitor p21. Because p21 also has an inhibitory effect on p53-mediated apoptosis, the suppression of p53-induced p21 expression would be expected to result in the preferential induction of apoptosis. However, p21 also has tumor-suppressive properties. In this study, we developed an adenovirus vector that expresses p53 and suppresses p21 simultaneously to enhance p53-mediated apoptosis.


METHODS
We constructed a replication-deficient recombinant adenovirus (Ad-p53/miR-p21) that enabled cocistronic expression of the p53 protein and artificial microRNAs that targeted p21, and examined the therapeutic effectiveness of this vector in vitro and in vivo.


RESULTS
The levels of p21 were significantly attenuated following infection with Ad-p53/miR-p21. In colorectal and hepatocellular carcinoma cells, infection with Ad-p53/miR-p21 augmented apoptosis as compared with an adenovirus that expressed p53 alone (Ad-p53/miR-control). Ad-p53/miR-p21 also significantly increased the chemosensitivity of cancer cells to adriamycin (doxorubicin). In a xenograft tumor model in nude mice, tumor volume was significantly decreased following the direct injection of Ad-p53/miR-p21 into the tumor, as compared with the injection of Ad-p53/miR-control.


CONCLUSIONS
These results suggest that adenovirus-mediated transduction of p53 and p21-specific microRNAs may be useful for gene therapy of human cancers.
Idogawa
Masashi
M
Department of Molecular Biology, Cancer Research Institute, Sapporo Medical University, Sapporo, Japan.
Sasaki
Yasushi
Y
Suzuki
Hiromu
H
Mita
Hiroaki
H
Imai
Kohzoh
K
Shinomura
Yasuhisa
Y
Tokino
Takashi
T
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis; D001483:Base Sequence; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics* / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D005260:Female; D005822:Genetic Vectors / Q000235:genetics; D045325:HCT116 Cells; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D009374:Neoplasms, Experimental / Q000235:genetics / Q000473:pathology / Q000628:therapy; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
D000903:Antibiotics, Antineoplastic; D050759:Cyclin-Dependent Kinase Inhibitor p21; D035683:MicroRNAs; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; D004317:Doxorubicin