Tumor Targeting of MMP-2/9 Activatable Cell-Penetrating Imaging Probes Is Caused by Tumor-Independent Activation

Abstract

This study demonstrates that the tumor targeting of radiolabeled MMP-2/9 ACPPs is most likely caused by the activation in the vascular compartment rather than tumor-specific activation, as suggested earlier. The results in the present paper indicate that different and more tissue-specific enzyme-ACPP combinations are needed to unleash the full potential of the elegant ACPP concept in living animals.