Systemic delivery of a breast cancer-detecting adenovirus using targeted microbubbles.
One of the major limitations of cancer gene therapy using recombinant human adenovirus (Ad) is rapid Ad inactivation from systemic delivery. To eliminate this, biotin-coated ultrasound contrast agents, or microbubbles (MBs), were streptavidin-coupled with biotinylated antibodies to three distinct tumor vasculature-associated receptors (α(V)β(3) integrin, P-selectin and vascular endothelial growth factor receptor-2) for systemic targeting of a previously generated vector Ad5/3-Id1-SEAP-Id1-mCherry. This cancer-specific, dual-reporter vector was loaded in the targeted MBs and confirmed by confocal microscopy. MB loading capacity was estimated by functional assays as 4.72 ± 0.2 plaque forming unit (PFU) per MB. Non-loaded (free) Ad particles were effectively inactivated by treatment with human complement. The Ad-loaded, targeted-MBs were injected systemically in mice bearing MDA-MB-231 tumors (Grp 1) and compared with two control groups: Ad-loaded, non-targeted MBs (Grp 2) and free Ad (Grp 3) administered under the same conditions. Two days after administration the blood levels of secreted embryonic alkaline phosphatase (SEAP) reporter in Grp 1 mice (16.1 ng ml(-1) ± 2.5) were significantly higher (P<0.05) than those in Grp 2 (9.75 ng ml(-1) ± 1.5) or Grp 3 (4.26 ng ml(-1) ± 2.5) animals. The targeted Ad delivery was also confirmed by fluorescence imaging. Thus, Ad delivery by targeted MBs holds potential as a safe and effective system for systemic Ad delivery for the purpose of cancer screening.
Department of Radiology, University of Alabama at Birmingham, 35294, USA.
J M
JM
Warram
A G
AG
Sorace
R
R
Saini
A V
AV
Borovjagin
K
K
Hoyt
K R
KR
Zinn
D000256:Adenoviridae; D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000628:therapy; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D039482:Integrin alpha5 / Q000235:genetics / Q000627:therapeutic use; D051379:Mice; D008819:Mice, Nude; D045423:Microbubbles / Q000627:therapeutic use*; D019007:P-Selectin / Q000235:genetics / Q000627:therapeutic use; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000627:therapeutic use
D039482:Integrin alpha5; D019007:P-Selectin; D040301:Vascular Endothelial Growth Factor Receptor-2