Design and Biological Evaluation of Cell-Penetrating Peptide–Doxorubicin Conjugates as Prodrugs

Abstract

Doxorubicin (Dox) is a hydrophilic anticancer drug that has short retention time due to the efficient efflux in some cancer cells (e.g., ovarian adenocarcinoma SK-OV-3). Cyclic [W(RW)(4)] and the corresponding linear peptide (RW)(4) were conjugated with Dox through an appropriate linker to afford cyclic [W(RW)(4)]-Dox and linear (RW)(4)-Dox conjugates to enhance the cellular uptake and cellular retention of the parent drug for sustained anticancer activity. Comparative antiproliferative assays between covalent (cyclic [W(RW)(4)]-Dox and linear (RW)(4)-Dox) and the corresponding noncovalent physical mixtures of the peptides and Dox were performed. Cyclic [W(RW)(4)]-Dox inhibited the cell proliferation of human leukemia (CCRF-CEM) (62-73%), ovarian adenocarcinoma (SK-OV-3) (51-74%), colorectal carcinoma (HCT-116) (50-67%), and breast carcinoma (MDA-MB-468) (60-79%) cells at a concentration of 1 μM after 72-120 h of incubation. Cyclic [W(RW)(4)]-Dox exhibited higher antiproliferative activity than linear (RW)(4)-Dox in all cancer cells with the highest activity observed after 72 h. Flow cytometry analysis showed 3.6-fold higher cellular uptake of cyclic [W(RW)(4)]-Dox than Dox alone in SK-OV-3 cells after 24 h incubation. The cellular hydrolysis study showed that 99% of cyclic [W(RW)(4)]-Dox was hydrolyzed intracellularly within 72 h and released Dox. These data suggest that cyclic [W(RW)(4)]-Dox can be used as a potential prodrug for improving the cellular delivery and retention of Dox.

Doxorubicin Conjugated to Immunomodulatory Anticancer Lactoferrin Displays Improved Cytotoxicity Overcoming Prostate Cancer Chemo resistance and Inhibits Tumour Development in TRAMP Mice

“…Following receptor mediated endocytosis, bLf enters the endo-lysosome21 which could cause the cleavage of the drug from the protein due to the action of the digestive enzymes and the acidic environment leading to hydrolysis of covalent bond37. This results in nuclear Dox accumulation which was confirmed by reduced fluorescence of nuclear counterstain DAPI due to the competitive binding by Dox, proving our hypothesis that bLf-Dox leads to the increased retention of the drug.…”

Self-assembly of peptides to nanostructures

“…49,50 Our findings showed that the cyclic nature of the peptide was a critical element in the self-assembly process and their biological activity possibly because of the constrained structure and different orientation of amino acids in their secondary structure.…”

Design of a doxorubicin-peptidomimetic conjugate that targets HER2-positive cancer cells

“…Although the final compound was obtained, purification was difficult because of its very low yield. Later, by adopting the procedure described by Nasrolahi Shirazi et al [30], we tried to synthesize the conjugate. However, in the preliminary step, attaching t-butyl anhydride to the C-terminal of compound 5 posed a problem.…”