Acid-Sensitive Peptide-Conjugated Doxorubicin Mediates the Lysosomal Pathway of Apoptosis and Reverses Drug Resistance in Breast Cancer

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• 作者：Yuan Sheng ; Jinhui Xu ; Yiwen You ; Feifei Xu ; Yun Chen
• 刊名：Molecular Pharmaceutics
• 出版年：2015
• 出版时间：July 6, 2015
• 年：2015
• 卷：12
• 期：7
• 页码：2217-2228
• 全文大小：642K
• ISSN：1543-8392

文摘

The extended use of doxorubicin (DOX) could be limited because of the emergence of drug resistance associated with its treatment. To reverse the drug resistance, two thiol-modified peptide sequences HAIYPRHGGC and THRPPMWSPVWPGGC were, respectively, conjugated to DOXO-EMCH, forming a maleimide bridge in this study (i.e., T10-DOX and T15-DOX). The structures and properties of peptide鈥揇OX conjugates were characterized using ¹H NMR, ¹³C NMR, mass spectrometry, and high-performance liquid chromatography. Their stability was also evaluated. By using MCF-7/ADR cells as an in vitro model system and nude mice bearing MCF-7/ADR xenografts as an in vivo model, the ability of these novel peptide鈥揇OX conjugates to reverse drug resistance was accessed as compared with free DOX. As a result, the IC₅₀ values for T10-DOX and T15-DOX significantly decreased (31.6 卤 1.6 渭M and 27.2 卤 0.8 渭M), whereas the percentage of apoptotic cell population increased (35.4% and 39.3%). The in vivo extent of inhibition was more evident in the mice groups treated with peptide鈥揇OX conjugates (59.6 卤 8.99% and 46.4 卤 6.63%), which had DOX primarily accumulated in tumor. These conjugates also showed a longer half-life in plasma and cleared much more slowly from the body. Furthermore, T10-DOX may be more effective than T15-DOX with a higher efficacy and a lower side effect. Most importantly, evidence was provided to support the enhanced intracellular drug accumulation and the induction of lysosomal pathway of apoptosis underlying the drug resistance. As an endosomal/lysosomal marker, cathepsin D permealized the destabilized organelle membrane and was detected in the cytoplasm, leading to the activation of the effector caspase-3 in cell apoptosis. This report is among the first to demonstrate that peptide鈥揇OX-like conjugates promote apoptosis through the initiation of the lysosomal pathway.