title: Adenovirus calcium phosphate coprecipitates enhance squamous cell carcinoma gene transfer.
abstract: OBJECTIVE
  Adenoviral-mediated gene transfer offers a potential new treatment strategy for squamous cell cancer of the head and neck (SCCHN). Initial studies on some SCCHN cell lines have shown that these cells can be resistant to adenovirus-mediated gene transfer, requiring large amounts of vector and long infection times. The objectives of this study were to identify the barriers to gene transfer in three SCCHN lines, FaDu, SCC-9, and SCC-15, and to develop a method to circumvent the obstacles. We hypothesized that a low expression of adenovirus receptors may limit adenovirus infection and this may be overcome by using adenovirus complexed with calcium phosphate coprecipitates.
  
  
  METHODS
  Using standard cell and molecular biology techniques, the infectability of SCCHN cells was investigated.
  
  
  RESULTS
  Using Cy3-labeled adenovirus, we found minimal binding of adenovirus to FaDu cells and variable levels of binding among SCC-9 and SCC-15 cells. Northern blot analysis indicated that messenger RNA (mRNA) transcripts for coxsackie-adenovirus receptor, which binds adenovirus, were absent in FaDu cells but present in SCC-9 and SCC-15 cells. Integrin alphavbeta5, which binds and facilitates internalization of adenovirus, were expressed at low levels in all three cell types. We overcame these barriers by using adenovirus complexed with calcium phosphate precipitates. Total transgene expression and the number of cells expressing transgene were increased in all three cancer lines using adenovirus complexed with calcium phosphate precipitates compared with adenovirus that was not complexed.
  
  
  CONCLUSIONS
  Data in the present study suggest that adenovirus-mediated gene transfer to SCCHN cell lines is a result of limited viral receptors. Delivering adenovirus in a calcium phosphate coprecipitate enhanced gene transfer and, perhaps, the therapeutic index.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Yi
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: S
authors.initials: S
authors.lastname: Graham
authors.forename: J
authors.initials: J
authors.lastname: Zabner
authors.forename: M J
authors.initials: MJ
authors.lastname: Welsh
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D015152:Blotting, Northern; D002130:Calcium Phosphates / Q000494:pharmacology*; D002294:Carcinoma, Squamous Cell / Q000628:therapy*; D002460:Cell Line; D004770:Enterovirus; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006367:HeLa Cells; D006258:Head and Neck Neoplasms / Q000628:therapy*; D006801:Humans; D007150:Immunohistochemistry; D016023:Integrins / Q000235:genetics; D051379:Mice; D018613:Microscopy, Confocal; D012333:RNA, Messenger / Q000235:genetics; D011991:Receptors, Virus / Q000235:genetics; D013997:Time Factors; D019076:Transgenes; D014407:Tumor Cells, Cultured
chemical_list: D002130:Calcium Phosphates; D016023:Integrins; D012333:RNA, Messenger; D011991:Receptors, Virus; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous