A novel apelin-receptor targeted contrast agent for molecular ultrasound imaging of tumor angiogenesis: in vitro evaluation

Zielsetzung:

To evaluate the binding specificity of a novel apelin-receptor-targeted contrast agent for molecular ultrasound imaging of tumor angiogenesis in vitro. Bracco Posterpreis

Material und Methodik:

Apelin-receptor (APJ) expression of human umbilical vein endothelial cells (HUVECs) was confirmed with immunofluorescent staining of HUVECs with a biotinylated anti-APJ antibody and a streptavidin-conjugated fluorescent dye. Target-ready microbubbles (Vevo MicroMarker, Visualsonics, Toronto, Canada) were either conjugated with the biotinylated anti-APJ antibody or a biotinylated isotype-matched control antibody. Concentration and size of both types of targeted microbubbles were assessed. HUVECs were grown on microscopic glass slides and incubated with either APJ-targeted microbubbles or control microbubbles for 5 min, then cells were washed with phosphate buffered saline and the binding of each type of microbubble per cell was visually assessed under an inverted brightfield microscope by counting microbubbles manually. An unpaired t-test was used for statistical analysis of binding specificity for each type of microbubble.

Ergebnisse:

Mean number of microbubbles bound to HUVEC was 5.57 per cell for APJ-targeted and 1.78 for control microbubbles, respectively. APJ-targeted microbubbles showed a significantly higher binding specificity to HUVECs than control microbubbles (p = 0.021). Binding of microbubbles corresponded to APJ expression proven by immunohistochemistry.

Schlussfolgerungen:

APJ expression of HUVECs targeted by a novel contrast agent for molecular ultrasound imaging may serve as a potential imaging biomarker in tumor angiogenesis.