Adenovirus with hexon Tat-protein transduction domain modification exhibits increased therapeutic effect in experimental neuroblastoma and neuroendocrine tumors

J Virol. 2011 Dec;85(24):13114-23. doi: 10.1128/JVI.05759-11. Epub 2011 Sep 28.

Abstract

Adenovirus serotype 5 (Ad5) is widely used as an oncolytic agent for cancer therapy. However, its infectivity is highly dependent on the expression level of coxsackievirus-adenovirus receptor (CAR) on the surfaces of tumor cells. Furthermore, infected cells overproduce adenovirus fiber proteins, which are released prior to cell lysis. The released fibers block CAR on noninfected neighboring cells, thereby preventing progeny virus entry. Our aim was to add a CAR-independent infection route to Ad5 to increase the infectivity of tumor cells with low CAR expression and prevent the fiber-masking problem. We constructed Ad5 viruses that encode the protein transduction domain (PTD) of the HIV-1 Tat protein (Tat-PTD) in hypervariable region 5 (HVR5) of the hexon protein. Tat-PTD functions as a cell-penetrating peptide, and Tat-PTD-modified Ad5 showed a dramatic increased transduction of CAR-negative cell lines compared to unmodified vector. Moreover, while tumor cell infectivity was severely reduced for Ad5 in the presence of fiber proteins, it was only marginally reduced for Tat-PTD-modified Ad5. Furthermore, because of the sequence alteration in the hexon HVR, coagulation factor X-mediated virus uptake was significantly reduced. Mice harboring human neuroblastoma and neuroendocrine tumors show suppressed tumor growths and prolonged survival when treated with Tat-PTD-modified oncolytic viruses. Our data suggest that modification of Ad5 with Tat-PTD in HVR5 expands its utility as an oncolytic agent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviruses, Human / genetics
  • Adenoviruses, Human / growth & development*
  • Animals
  • Capsid Proteins / genetics
  • Capsid Proteins / metabolism*
  • Disease Models, Animal
  • Female
  • Humans
  • Male
  • Mice
  • Mice, Nude
  • Neuroblastoma / mortality
  • Neuroblastoma / pathology
  • Neuroblastoma / therapy*
  • Neuroendocrine Tumors / mortality
  • Neuroendocrine Tumors / pathology
  • Neuroendocrine Tumors / therapy*
  • Oncolytic Viruses / genetics
  • Oncolytic Viruses / growth & development*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Survival Analysis
  • Transduction, Genetic
  • Treatment Outcome
  • Virus Internalization*
  • tat Gene Products, Human Immunodeficiency Virus / genetics
  • tat Gene Products, Human Immunodeficiency Virus / metabolism*

Substances

  • Capsid Proteins
  • Recombinant Fusion Proteins
  • hexon capsid protein, Adenovirus
  • tat Gene Products, Human Immunodeficiency Virus