Enzyme-triggered delivery of chlorambucil from conjugates based on the cell-penetrating peptide BP16. Issue 5 (4th December 2014)

• Record Type: Journal Article
• Authors: Soler, Marta; González-Bártulos, Marta; Figueras, Eduard; Ribas, Xavi; Costas, Miquel; Massaguer, Anna; Planas, Marta; Feliu, Lidia
• Is Part Of: Organic & biomolecular chemistry. Volume 13:Issue 5(2015)
• Page Start: 1470
• Page End: 1480
• Publication Date: 2014-12-04
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c4ob01875c
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : The combination of the cell-penetrating peptideBP16 with the enzymatic cleavable sequence Gly-Phe-Leu-Gly constitutes a drug delivery system for the effective uptake and release of chlorambucil in cancer cells. Abstract : The undecapeptide KKLFKKILKKL-NH2 (BP16 ) is a non-toxic cell-penetrating peptide (CPP) that is mainly internalized into cancer cells through a clathrin dependent endocytic mechanism and localizes in late endosomes. Moreover, this CPP is able to enhance the cellular uptake of chlorambucil (CLB) improving its cytotoxicity. In this work, we further explored the cell-penetrating properties ofBP16 and those of its arginine analogueBP308 . We investigated the influence on the cytotoxicity and on the cellular uptake of conjugating CLB at the N- or the C-terminal end of these undecapeptides. The effect of incorporating the cathepsin B-cleavable sequence Gly-Phe-Leu-Gly in CLB-BP16 and CLB-BP308 conjugates was also evaluated. The activity of CLB was significantly improved when conjugated at the N- or the C-terminus ofBP16, or at the N-terminus ofBP308 . While CLB alone was not active (IC50 of 73.7 to >100 μM), the resulting conjugates displayed cytotoxic activity against CAPAN-1, MCF-7, PC-3, 1BR3G and SKMEL-28 cell lines with IC50 values ranging from 8.7 to 25.5 μM. These results were consistent with the internalization properties observed for the corresponding 5(6)-carboxyfluorescein-labeled conjugates. The presence of the tetrapeptide Gly-Phe-Leu-Gly at either the N- or the C-terminus of CLB-BP16 conjugates further increased the efficacy of CLB (IC50 of 3.6 to 16.2 μM), which could be attributed to its selective release in the lysosomal compartment. Enzymatic assays with cathepsin B showed the release of CLB-Gly-OH from these sequences within a short time. Therefore, the combination ofBP16 with an enzymatic cleavable sequence can be used as a drug delivery system for the effective uptake and release of drugs in cancer cells.