In vivo biodistribution of radiolabeled MMP‐2/9 activatable cell‐penetrating peptide probes in tumor‐bearing mice

In conclusion, this study suggests that tumoral ACPP uptake in these tumor models originates from probe activation in the vasculature instead of tumor‐specific MMP activation. Novel ACPPs that target tissue‐specific proteases without nonspecific activation may unleash the full potential of the elegant ACPP concept. Copyright © 2014 John Wiley & Sons, Ltd.We present the in vivo biodistribution of matrix metalloproteinase activatable cell‐penetrating imaging probes (ACPP) in mice bearing subcutaneous HT‐1080 tumors with high MMP expression, and in control mice bearing subcutaneous BT‐20 tumors with low MMP expression. The ACPP probes were earlier reported to be activated specifically in MMP‐expressing tumors, but a recent biodistribution study on these probes in HT‐1080 tumor‐bearing mice at 6 and 24 h post‐ACPP injection suggested that probe activation occurred already in the vasculature followed by aspecific tumor targeting. We provide additional data that tumoral ACPP uptake in both mice models at 3 h post‐ACPP injection originates from probe activation in the vasculature instead of tumor‐specific MMP activation.

Source: Contrast Media and Molecular Imaging - May 14, 2014 Category: Radiology Authors: Sander M. J. Duijnhoven, Marc S. Robillard, Klaas Nicolay, Holger Grüll Tags: Full Paper Source Type: research