Enhancement of the cancer targeting specificity of buforin lib by fusion with an anionic peptide via a matrix metalloproteinases-cleavable linker

Buforin Ilb is a novel cell-penetrating anticancer peptide derived from histone H2A. In this study, we enhanced the cancer targeting specificity of buforin Ilb using a tumor-associated enzyme-controlled activation strategy. Buforin Ilb was fused with an anionic peptide (modified magainin intervening sequence, MMIS), which neutralizes the positive charge of buforin lib and thus renders it inactive, via a matrix metalloproteinases (MMPs)-cleavable linker. The resulting MMIS:buforin Ilb fusion peptide was completely inactive against MMPs-nonproducing cells. However, when the fusion peptide was administrated to MMPs-producing cancer cells, it regained the killing activity by releasing free buforin Ilb through MMPs-mediated cleavage. Moreover, the activity of the fusion peptide toward MMPs-producing cancer cells was significantly decreased when the cells were pretreated with a MMP inhibitor. Taken together, these data indicate that the cancer targeting specificity of MMIS:buforin Ilb is enhanced compared to the parent peptide by reactivation at the specialized areas where MMPs are pathologically produced. (C) 2011 Elsevier Inc. All rights reserved.