A number of cyclic peptides containing a positively charged ring composed of arginine residues attached to hydrophobic tail made of tryptophan residues through a lysine linker namely [R5K]W5, [R6K]W5, [R5K]W6, [R7K]W5, [R5K]W7, [R6K]W6, and [R7K]W7 were synthesized and evaluated as molecular transporters. The peptides were evaluated for their ability to deliver, fluorescence-labeled cell-impermeable negatively charged phosphopeptide (F′-GpYEEI), and fluorescent labeled anti-HIV drugs (F′-FTC and F′-d4T). The results indicated that the presence of positively charged arginine residues on the ring and hydrophobic tryptophan residues in a sequential linear outside the ring was an optimal approach to improve the intracellular uptake of cargo molecules through non-covalent interactions. Some of these peptides were also evaluated for their efficiency for intracellular delivery of siRNA to triple-negative breast cancer cell lines in the presence and absence of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). [R6K]W6 and [R5K]W5 were found to be very efficient in the delivery of siRNA. Furthermore, co-formulation of peptides with lipid DOPE significantly enhanced the efficiency of siRNA delivery compared to peptide alone. Silencing of kinesin spindle protein (KSP) and Janus kinase 2 (JAK2) was evaluated in MDA-MB-231 cells in the presence of the peptides. The addition of DOPE significantly enhanced the silencing efficiency for all selected peptides.
A chemotherapeutic drug, doxorubicin (Dox) was covalently conjugated to the cyclic peptide [R5K]W7A and linear peptide R5KW7A, and the biological activity was evaluated in cell-based assays. Comparative antiproliferative assays between covalently conjugated peptide-Dox and the corresponding noncovalent physical mixtures of the peptides and Dox were performed. The conjugation of Dox with cyclic [R5K]W7A-Dox exhibited similar antiproliferative activity compared to Dox alone after 72 h incubation time in all cancer cell lines, such as leukemia, ovarian and gastric cancer cells. However, [R5K]W7A-Dox significantly reduced the cell cytotoxicity in normal cell lines such as normal heart muscle and normal kidney cells after 72 h when compared with Dox alone. These results revealed that this cyclic peptide prodrug can be used as a potential candidate for the treatment of cancer cells with reduced side effects against normal cells in the body.
| Identifer | oai:union.ndltd.org:chapman.edu/oai:digitalcommons.chapman.edu:pharmaceutical_sciences_dissertations-1001 |
| Date | 18 December 2019 |
| Creators | Mozaffari, Saghar |
| Publisher | Chapman University Digital Commons |
| Source Sets | Chapman University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Pharmaceutical Sciences (Ph.D.) Dissertations |
| Rights | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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