HER2 Targeted Molecular MR Imaging Using a De Novo Designed Protein Contrast Agent
Figure 3
In vivo cancer imaging of contrast agent uptake, retention and distribution in multiple different normal host organs and in both SKOV-3 (HER2 positive, right) and MDA-MB-231 (HER2 negative, left) xenografts in balb/c nude mice (Charles River laboratory).
(A) NIR fluorescence imaging (Kodak 8000) revealed that ProCA1-Affi is able to target to the HER2 positive tumor (SKOV-3, right) 24 hr after injection from tail vein. No significant near IR signal was detected in the HER2 negative tumor (MDA-MB-231, left) (n = 6, P<0.05). (B) Fast spin echo and (C) gradient echo transversal MR images collected prior to injection and at various time points post injection of 3.0 mM of ProCA1-affi-m in HEPES saline via tail vein. The MRI signal on the positive tumor (SKOV-3, right) exhibits significant enhancement at 3 hr post injection and reaches maximum enhancement at 24 hours post injection (n = 6, P<0.05). The slight differences in MRI signals result from the use of different pulse sequences for imaging (Methods). (D). NIR images of the dissected mouse organs. General bio-distribution was obtained based on the NIR signal and western blot assay. The ProCA1-affi-m mainly distributed in the positive tumor, liver and kidney.