Increased safety with preserved antitumoral efficacy on hepatocellular carcinoma with dual-regulated oncolytic adenovirus.
OBJECTIVE
A dual-regulated adenovirus variant CNHK500, in which human telomerase reverse transcriptase promoter drove the adenovirus 5 (Ad5) E1a gene and hypoxia-response promoter controlled the E1b gene, was engineered. This virus has broad anticancer spectrum and higher specificity compared with mono-regulated adenovirus CNHK300. The objective of the current study is to show its antitumor selectivity and therapeutic potential.


METHODS
The antitumor specificity of human telomerase reverse transcriptase and hypoxia response promoters was evaluated in a panel of tumor and normal cells. Under the control of these promoters, the tumor-selective expression of E1a and E1b genes was evaluated. Further in vitro antitumor specificity and potency of this virus were characterized by viral replication and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Subsequently, hepatocellular carcinoma xenografts were established to evaluate CNHK500 antitumor efficacy in vivo by different routes of virus administration and different dosages.


RESULTS
Human telomerase reverse transcriptase and hypoxia response promoters were activated in a tumor-selective manner or under hypoxia treatment in a broad panel of cells. Selective adenoviral early gene expression, efficient viral replication, and oncolysis were observed in all tested cancer cells with more attenuated replication capacity in normal cells. Significant regression of hepatocellular carcinoma xenografts and prolonged survival were observed by either i.t. or i.v. administration.


CONCLUSIONS
CNHK500 greatly reduced side effects in normal cells via dual control of adenoviral essential genes while still preserving potent antitumor efficacy on broad-spectrum cancer cells in vitro and in vivo. It can be used as a powerful therapeutic agent not only for liver cancers but also for other solid tumors.
Zhang
Qi
Q
Laboratory of Viral and Gene Therapy, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Hangzhou, China.
Chen
Guihua
G
Peng
Linhui
L
Wang
Xinghua
X
Yang
Yang
Y
Liu
Chen
C
Shi
Wenfang
W
Su
Changqing
C
Wu
Hongping
H
Liu
Xinyuan
X
Wu
Mengchao
M
Qian
Qijun
Q
D000256:Adenoviridae / Q000235:genetics; D017500:Adenovirus E1A Proteins / Q000096:biosynthesis / Q000235:genetics; D017501:Adenovirus E1B Proteins / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000628:therapy* / Q000821:virology; D015687:Cell Hypoxia / Q000235:genetics*; D045744:Cell Line, Tumor; D017931:DNA Primers; D015870:Gene Expression; D006801:Humans; D008113:Liver Neoplasms / Q000628:therapy* / Q000821:virology; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000628:therapy* / Q000821:virology; D050130:Oncolytic Virotherapy / Q000379:methods*; D050504:Oncolytic Viruses / Q000235:genetics*; D011401:Promoter Regions, Genetic; D019098:Telomerase / Q000235:genetics; D014158:Transcription, Genetic; D023041:Xenograft Model Antitumor Assays
D017500:Adenovirus E1A Proteins; D017501:Adenovirus E1B Proteins; D017931:DNA Primers; D019098:Telomerase