Hits:

Indexed by:Journal Papers

Date of Publication:2016-12-15

Journal:PHYTOMEDICINE

Included Journals:SCIE、PubMed、Scopus

Volume:23

Issue:14

Page Number:1778-1786

ISSN No.:0944-7113

Key Words:Baicalein; 10-hydroxy camptothecin; Anti-cancer; Topoisomerase I; p53; Apoptosis

Abstract:Background: 10-Hydroxy camptothecin (HCPT), a naturally occurring alkaloid, is a clinical drug for cancer chemotherapy. Baicalein (BA) is a flavonoid extracted from the root of Scutellaria baicalensis. The synergistic anti-cancer effect of BA and HCPT has not been reported.
   Purpose: To explore whether and how BA enhances the anti-cancer effect of HCPT in BGC823 cells.
   Methods: Cell viability was measured by MTT assay. Apoptosis and cell cycle were analyzed through flow cytometry and western blotting analysis. DNA damage was determined by a comet assay. The activity of topoisomerase I (Topo I) was detected by the plasmid DNA relaxation assay. The synergistic anti-cancer effect of BA and HCPT in vivo was tested by BGC823 xenografted tumor model.
   Results: BA at non-toxic doses prominently enhanced the anti-cancer activities of HCPT in BGC823, MCF7 and SMMC7721 cells. Combination treatment of BA and HCPT induced BGC823 cells apoptosis mainly via intrinsic rather than extrinsic pathways, and preferentially arresting cell cycle in G1 and G2 phases with the aid of p21. Of note, p53, the upstream regulator of cell apoptosis and cycle, was increased by 5 folds in combination group. It helped to further trigger DNA damage and inhibit Topo I catalytic activity after combination treatment of BA and HCPT. Moreover, the BGC823 xenografted tumor growth rate in nude mice was repressed in a greater degree (P < 0.01) in the combinational group than the single-drug group.
   Conclusion: HCPT and BA, a new and effective combination therapy, synergistically target Topo I and up-regulate p53 to induce cell apoptosis and cell cycle arrest. (C) 2016 Elsevier GmbH. All rights reserved.