title: Coxsackie and adenovirus receptor binding ablation reduces adenovirus liver tropism and toxicity.
abstract: Human adenovirus-based vectors have emerged as a new promising vehicle for in vivo gene transfer-mediated therapy. However, the full potential of this methodology has not been fully realized because of the nonspecific tissue distribution of adenoviral vectors. Adenovirus infection is initiated by forming a complex between the fiber protein and a ubiquitously expressed host cell membrane protein, coxsackie B virus and adenovirus receptor (CAR). Therefore, ablating the adenovirus vector's ability to bind to the CAR is the first step in redirecting adenoviral tropism. To ablate CAR binding, we mutated the Bbeta sheet of the fiber knob, generating CAR-binding ablated replication-incompetent (dl-K420A-Z) and replication-competent (YKLK420A) adenoviral vectors. The in vitro transduction efficiency of dl-K420A-Z was significantly reduced in comparison to dl-LacZ carrying the wild-type fiber in CAR-positive cells but not in CAR-negative cells, suggesting that the mutation introduced in the Bbeta sheet of the fiber knob could disable the CAR-dependent transduction pathway. The in vivo transduction was also dramatically reduced in the liver and other organs for mice treated with dl-K420A-Z, compared with a cognate control vector, dl-LacZ. Concomitant with this attenuated gene transfer efficiency in vivo was a substantial reduction in the amount of general toxicity observed in the YKL-K420A-treated mice. Diminished toxicity was surmised from quantitative measurement of serum level of enzymes for liver and kidney function, hematologic chemistries, histopathology, and differences in lethality. Significant decrease in serum transaminases (alanine transferase [ALT] and aspartate transferase [AST]) was observed in mice treated with YKL-K420A. In addition, the lethality was lower in the YKLK420A- treated groups compared to the YKL-1-treated groups at all doses examined. Furthermore, the hepatopathologic analysis revealed that YKL-1 induced focal zonal necrosis and hepatocyte degeneration, while YKL-K420A induced mild spotty necrosis. In summary, this decreased vector tropism of CAR-binding ablated adenoviruses in normal tissues may increase the amount of virus available for infecting tumor cells and thus increase the antitumor efficacy with fewer unwanted side effects.
authors.affiliation: Brain Korea 21 Project for Medical Science, Institute for Cancer Research, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, 120-752, Korea.
authors.forename: Chae-Ok
authors.initials: CO
authors.lastname: Yun
authors.forename: A-Rum
authors.initials: AR
authors.lastname: Yoon
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Yoo
authors.forename: Hoguen
authors.initials: H
authors.lastname: Kim
authors.forename: Minjung
authors.initials: M
authors.lastname: Kim
authors.forename: Taeyong
authors.initials: T
authors.lastname: Ha
authors.forename: Gwi Eon
authors.initials: GE
authors.lastname: Kim
authors.forename: Hyunhee
authors.initials: H
authors.lastname: Kim
authors.forename: Joo-Hang
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000256:Adenoviridae / Q000235:genetics / Q000472:pathogenicity*; D000257:Adenoviridae Infections / Q000821:virology; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D006801:Humans; D008099:Liver / Q000166:cytology / Q000378:metabolism / Q000821:virology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D011485:Protein Binding; D011991:Receptors, Virus / Q000235:genetics / Q000378:metabolism*; D018523:Tropism; D014779:Virus Replication
chemical_list: C568771:CLMP protein, human; C568772:CLMP protein, mouse; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D011991:Receptors, Virus; C085301:adenovirus receptor; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase