title: Telomerase-dependent oncolytic adenovirus for cancer treatment.
abstract: Conditionally replicative adenovirus (CRAD) is an attractive anticancer agent as it can selectively replicate in tumor cells. Expression of telomerase reverse transcriptase (TERT) is a unique tumor cell characteristic, being absent in normal postmitotic cells. Thus, we constructed a TERT promoter regulated CRAD for tumor-specific oncolysis by replacing the endogenous adenovirus E1A promoter with that of human TERT (Adv-TERTp-E1A). We showed that its replication was severely attenuated in TERT-negative cells, but that it replicated almost as efficiently as wild-type adenovirus in TERT-positive cells. Accordingly, Adv-TERTp-E1A conferred cytopathicity to TERT-positive, but not TERT-negative, cells. In vivo replication of Adv-TERTp-E1A after local administration into a xenograft model of human hepatocellular carcinoma in nude mice was demonstrated by an increase in adenovirus titers in tumor extracts by several orders of magnitude between 6 h and 3 days postvector injection. Furthermore, significant inhibition of tumor growth with substantial necrotic tumor areas staining positively for adenovirus was observed with Adv-TERTp-E1A, but not with a control replication-deficient adenovirus. There was also the absence of hepatotoxicity in tumor-bearing animals after intratumoral delivery of the CRAD. The results indicate that the TERT promoter-driven CRAD is capable of tumor-selective replication and oncolysis in vitro and in vivo, and can be utilized as an adjuvant treatment agent for cancer.
authors.affiliation: Carl C. Icahn Center for Gene Therapy and Molecular Medicine, Mount Sinai School of Medicine, New York, NY, USA.
authors.forename: T-G
authors.initials: TG
authors.lastname: Huang
authors.forename: M J
authors.initials: MJ
authors.lastname: Savontaus
authors.forename: K
authors.initials: K
authors.lastname: Shinozaki
authors.forename: B V
authors.initials: BV
authors.lastname: Sauter
authors.forename: S L C
authors.initials: SL
authors.lastname: Woo
mesh_terms: D000256:Adenoviridae / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology; D000818:Animals; D016923:Cell Death; D003588:Cytopathogenic Effect, Viral; D004268:DNA-Binding Proteins; D018390:Gene Targeting / Q000379:methods; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000628:therapy* / Q000821:virology; D008114:Liver Neoplasms, Experimental / Q000235:genetics / Q000628:therapy* / Q000821:virology; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011401:Promoter Regions, Genetic; D019098:Telomerase / Q000235:genetics*; D014407:Tumor Cells, Cultured; D014779:Virus Replication
chemical_list: D004268:DNA-Binding Proteins; C509186:TERT protein, human; D019098:Telomerase; C509187:Tert protein, mouse