Amphiphilic cyclic cell-penetrating peptides composed of an increasing number of alternative tryptophan (W) and arginine (R) were synthesized and evaluated as a molecular transporter and for their ability to deliver doxorubicin (Dox) and large molecular weight molecules, such as siRNA and proteins. We prepared a cyclic peptide containing alternative tryptophan (W) and arginine (R) residues and a lysine containing a free side chain amino group. Cyclic peptide [(WR)8WK βA] was conjugated through the free side chain amino group of β-alanine with Dox via a glutarate linker to afford [(WR)8WK]bA-Dox conjugate. The conjugate inhibited the cell viability of ovarian adenocarcinoma (SK-OV-3) by 59% and triple-negative breast cancer cells, MDA-MB-231 and MCF-7, by 71% and 77%, respectively, at a concentration of 5 μM after 72 h of incubation. Furthermore, [(WR)8WKbA]-Dox conjugate (5 μM) inhibited the cell viability of Dox-resistant cells (MES-SA/MX2) by 92%, while the viability of cells incubated with free Dox was only 15% at 5 μM. The stability of Dox conjugate was observed at different time intervals using analytical HPLC when the conjugate was incubated with 25% human serum. The intracellular release of free Dox was assessed in CCRF-CEM cell line. The experiment exhibited that approximately 100% of free Dox was released from the conjugate intracellularly within 72 h.Cyclic peptide [WR]9 efficiently increased the intracellular delivery of siRNA to triple negative breast cancer cell lines (MDA-MB-231 and MDA-MB-468) by 15-folds and 9-folds, respectively, compared to siRNA alone. Flow cytometry (FACS) and confocal microscopy confirmed the uptake of Alexa-Fluor siRNA (AF-488 siRNA) in the presence of [WR]9 at different concentrations. The calculated binding affinity (BC50) of siRNA to the peptide was 1.9, indicating strong binding for siRNA to the peptide. As a result, the peptide siRNA combination displayed only minimal silencing efficiency for signal transducer and activator of transcription 3 (STAT3). Furthermore, the peptide showed concentration and time-dependent cargo uptake when physically mixed with green fluorescent protein (GFP) and red fluorescent protein (RFP)as model proteins. [WR]9 was also able to internalize therapeutically relevant histone protein at different ratios.
","abstract_html":"<p>Amphiphilic cyclic cell-penetrating peptides composed of an increasing number of alternative tryptophan (W) and arginine (R) were synthesized and evaluated as a molecular transporter and for their ability to deliver doxorubicin (Dox) and large molecular weight molecules, such as siRNA and proteins. We prepared a cyclic peptide containing alternative tryptophan (W) and arginine (R) residues and a lysine containing a free side chain amino group. Cyclic peptide [(WR)8WK βA] was conjugated through the free side chain amino group of β-alanine with Dox via a glutarate linker to afford [(WR)8WK]bA-Dox conjugate. The conjugate inhibited the cell viability of ovarian adenocarcinoma (SK-OV-3) by 59% and triple-negative breast cancer cells, MDA-MB-231 and MCF-7, by 71% and 77%, respectively, at a concentration of 5 μM after 72 h of incubation. Furthermore, [(WR)8WKbA]-Dox conjugate (5 μM) inhibited the cell viability of Dox-resistant cells (MES-SA/MX2) by 92%, while the viability of cells incubated with free Dox was only 15% at 5 μM. The stability of Dox conjugate was observed at different time intervals using analytical HPLC when the conjugate was incubated with 25% human serum. The intracellular release of free Dox was assessed in CCRF-CEM cell line. The experiment exhibited that approximately 100% of free Dox was released from the conjugate intracellularly within 72 h.Cyclic peptide [WR]9 efficiently increased the intracellular delivery of siRNA to triple negative breast cancer cell lines (MDA-MB-231 and MDA-MB-468) by 15-folds and 9-folds, respectively, compared to siRNA alone. Flow cytometry (FACS) and confocal microscopy confirmed the uptake of Alexa-Fluor siRNA (AF-488 siRNA) in the presence of [WR]9 at different concentrations. The calculated binding affinity (BC50) of siRNA to the peptide was 1.9, indicating strong binding for siRNA to the peptide. As a result, the peptide siRNA combination displayed only minimal silencing efficiency for signal transducer and activator of transcription 3 (STAT3). Furthermore, the peptide showed concentration and time-dependent cargo uptake when physically mixed with green fluorescent protein (GFP) and red fluorescent protein (RFP)as model proteins. [WR]9 was also able to internalize therapeutically relevant histone protein at different ratios.</p>","abstract_has_math":false,"creators":["Zoghebi, Khalid"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation","degree_discipline":"Pharmaceutical Sciences","degree_department":null,"school":null,"contributors":["Dr. Keykavous Parang","Dr. Rakesh Tiwari","Dr. Sun Yang","Dr. Simin Rahighi"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-05-01T07:00:00Z","date_published":"2022-05-01T07:00:00Z","updated_at":"2026-07-24T01:38:24Z","subjects":["Medicinal and Pharmaceutical Chemistry","Medicine and Health Sciences","Pharmacy and Pharmaceutical Sciences"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.chapman.edu/pharmaceutical_sciences_dissertations/15","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dr. Keykavous Parang","Dr. Rakesh Tiwari","Dr. Sun Yang","Dr. Simin Rahighi"]},{"key":"dc:creator","label":"Author","values":["Zoghebi, Khalid"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2024-04-18T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Pharmaceutical Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Medicinal and Pharmaceutical Chemistry","Medicine and Health Sciences","Pharmacy and Pharmaceutical Sciences"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.chapman.edu/pharmaceutical_sciences_dissertations/15"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Amphiphilic cyclic cell-penetrating peptides composed of an increasing number of alternative tryptophan (W) and arginine (R) were synthesized and evaluated as a molecular transporter and for their ability to deliver doxorubicin (Dox) and large molecular weight molecules, such as siRNA and proteins. We prepared a cyclic peptide containing alternative tryptophan (W) and arginine (R) residues and a lysine containing a free side chain amino group. Cyclic peptide [(WR)8WK βA] was conjugated through the free side chain amino group of β-alanine with Dox via a glutarate linker to afford [(WR)8WK]bA-Dox conjugate. The conjugate inhibited the cell viability of ovarian adenocarcinoma (SK-OV-3) by 59% and triple-negative breast cancer cells, MDA-MB-231 and MCF-7, by 71% and 77%, respectively, at a concentration of 5 μM after 72 h of incubation. Furthermore, [(WR)8WKbA]-Dox conjugate (5 μM) inhibited the cell viability of Dox-resistant cells (MES-SA/MX2) by 92%, while the viability of cells incubated with free Dox was only 15% at 5 μM. The stability of Dox conjugate was observed at different time intervals using analytical HPLC when the conjugate was incubated with 25% human serum. The intracellular release of free Dox was assessed in CCRF-CEM cell line. The experiment exhibited that approximately 100% of free Dox was released from the conjugate intracellularly within 72 h.Cyclic peptide [WR]9 efficiently increased the intracellular delivery of siRNA to triple negative breast cancer cell lines (MDA-MB-231 and MDA-MB-468) by 15-folds and 9-folds, respectively, compared to siRNA alone. Flow cytometry (FACS) and confocal microscopy confirmed the uptake of Alexa-Fluor siRNA (AF-488 siRNA) in the presence of [WR]9 at different concentrations. The calculated binding affinity (BC50) of siRNA to the peptide was 1.9, indicating strong binding for siRNA to the peptide. As a result, the peptide siRNA combination displayed only minimal silencing efficiency for signal transducer and activator of transcription 3 (STAT3). Furthermore, the peptide showed concentration and time-dependent cargo uptake when physically mixed with green fluorescent protein (GFP) and red fluorescent protein (RFP)as model proteins. [WR]9 was also able to internalize therapeutically relevant histone protein at different ratios.
"]},{"key":"dc:source","label":"Dc Source","values":["Zoghebi, K. Amphiphilic Cyclic Cell-Penetrating Peptides Containing Tryptophan and Arginine as Anticancer Agents and Drug Delivery System. [dissertation]. Irvine, CA: Chapman University; 2022. https://doi.org/10.36837/chapman.000344"]},{"key":"dc:title","label":"Title","values":["Amphiphilic Cyclic Cell-Penetrating Peptides Containing Tryptophan and Arginine as Anticancer Agents and Drug Delivery System"]}]}],"canonical_facts":{"dc:contributor":["Dr. Keykavous Parang","Dr. Rakesh Tiwari","Dr. Sun Yang","Dr. Simin Rahighi"],"dc:creator":["Zoghebi, Khalid"],"dc:date.available":["2024-04-18T07:00:00Z"],"dc:description.abstract":["Amphiphilic cyclic cell-penetrating peptides composed of an increasing number of alternative tryptophan (W) and arginine (R) were synthesized and evaluated as a molecular transporter and for their ability to deliver doxorubicin (Dox) and large molecular weight molecules, such as siRNA and proteins. We prepared a cyclic peptide containing alternative tryptophan (W) and arginine (R) residues and a lysine containing a free side chain amino group. Cyclic peptide [(WR)8WK βA] was conjugated through the free side chain amino group of β-alanine with Dox via a glutarate linker to afford [(WR)8WK]bA-Dox conjugate. The conjugate inhibited the cell viability of ovarian adenocarcinoma (SK-OV-3) by 59% and triple-negative breast cancer cells, MDA-MB-231 and MCF-7, by 71% and 77%, respectively, at a concentration of 5 μM after 72 h of incubation. Furthermore, [(WR)8WKbA]-Dox conjugate (5 μM) inhibited the cell viability of Dox-resistant cells (MES-SA/MX2) by 92%, while the viability of cells incubated with free Dox was only 15% at 5 μM. The stability of Dox conjugate was observed at different time intervals using analytical HPLC when the conjugate was incubated with 25% human serum. The intracellular release of free Dox was assessed in CCRF-CEM cell line. The experiment exhibited that approximately 100% of free Dox was released from the conjugate intracellularly within 72 h.Cyclic peptide [WR]9 efficiently increased the intracellular delivery of siRNA to triple negative breast cancer cell lines (MDA-MB-231 and MDA-MB-468) by 15-folds and 9-folds, respectively, compared to siRNA alone. Flow cytometry (FACS) and confocal microscopy confirmed the uptake of Alexa-Fluor siRNA (AF-488 siRNA) in the presence of [WR]9 at different concentrations. The calculated binding affinity (BC50) of siRNA to the peptide was 1.9, indicating strong binding for siRNA to the peptide. As a result, the peptide siRNA combination displayed only minimal silencing efficiency for signal transducer and activator of transcription 3 (STAT3). Furthermore, the peptide showed concentration and time-dependent cargo uptake when physically mixed with green fluorescent protein (GFP) and red fluorescent protein (RFP)as model proteins. [WR]9 was also able to internalize therapeutically relevant histone protein at different ratios.
"],"dc:identifier":["https://digitalcommons.chapman.edu/pharmaceutical_sciences_dissertations/15"],"dc:source":["Zoghebi, K. Amphiphilic Cyclic Cell-Penetrating Peptides Containing Tryptophan and Arginine as Anticancer Agents and Drug Delivery System. [dissertation]. Irvine, CA: Chapman University; 2022. https://doi.org/10.36837/chapman.000344"],"dc:subject":["Medicinal and Pharmaceutical Chemistry","Medicine and Health Sciences","Pharmacy and Pharmaceutical Sciences"],"dc:title":["Amphiphilic Cyclic Cell-Penetrating Peptides Containing Tryptophan and Arginine as Anticancer Agents and Drug Delivery System"],"thesis:degree_discipline":["Pharmaceutical Sciences"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T01:38:24Z"}