title: Acid-active cell-penetrating peptides for in vivo tumor-targeted drug delivery.
abstract: Cell-penetrating peptides (CPPs) such as transactivator of transcription (TAT) peptide have long been explored for promoting in vitro cell penetration and nuclear targeting of various cargos, but their positive charges cause strong nonspecific interactions, making them inapplicable for many in vivo applications. In this work, we used TAT to demonstrate a molecular modification approach for inhibiting nonspecific interactions of CPPs in the bloodstream while reactivating their functions in the targeted tissues or cells. The TAT lysine residues' amines were amidized to succinyl amides ((a)TAT), completely inhibiting TAT's nonspecific interactions in the blood compartment; once in the acidic tumor interstitium or internalized into cell endo/lysosomes, the succinyl amides in the (a)TAT were quickly hydrolyzed, fully restoring TAT's functions. Thus, (a)TAT-functionalized poly(ethylene glycol)-block-poly(ε-caprolactone) micelles achieved long circulation in the blood compartment and efficiently accumulated and delivered doxorubicin to tumor tissues, giving rise to high antitumor activity and low cardiotoxicity. This amidization strategy effectively and easily enables in vivo applications of CPPs.
authors.affiliation: Center for Bionanoengineering and State Key Laboratory for Chemical Engineering, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China 310027.
authors.forename: Erlei
authors.initials: E
authors.lastname: Jin
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Xuanrong
authors.initials: X
authors.lastname: Sun
authors.forename: Zhuxian
authors.initials: Z
authors.lastname: Zhou
authors.forename: Xinpeng
authors.initials: X
authors.lastname: Ma
authors.forename: Qihang
authors.initials: Q
authors.lastname: Sun
authors.forename: Jianbin
authors.initials: J
authors.lastname: Tang
authors.forename: Youqing
authors.initials: Y
authors.lastname: Shen
authors.forename: Edward
authors.initials: E
authors.lastname: Van Kirk
authors.forename: William J
authors.initials: WJ
authors.lastname: Murdoch
authors.forename: Maciej
authors.initials: M
authors.lastname: Radosz
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy*; D045744:Cell Line, Tumor; D057846:Cell-Penetrating Peptides / Q000627:therapeutic use*; D004317:Doxorubicin / Q000494:pharmacology*; D016503:Drug Delivery Systems; D005260:Female; D006801:Humans; D008823:Micelles; D008954:Models, Biological
chemical_list: D057846:Cell-Penetrating Peptides; D008823:Micelles; D004317:Doxorubicin