Ginkgetin inhibits the growth of DU-145 prostate cancer cells through inhibition of signal transducer and activator of transcription 3 activity.

Abstract

Signal transducer and activator of transcription 3 (STAT3) is constitutively activated in human cancers. Therefore, STAT3 is a therapeutic target of cancer drug discovery. We previously reported that natural products inhibited constitutively activated STAT3 in human prostate tumor cells. We used a dual-luciferase assay to screen 200 natural products isolated from herbal medicines and we identified ginkgetin obtained from the leaves of Ginkgo biloba L. as a STAT3 inhibitor. Ginkgetin inhibited both inducible and constitutively activated STAT3 and blocked the nuclear translocation of p-STAT3 in DU-145 prostate cancer cells. Furthermore, ginkgetin selectively inhibited the growth of prostate tumor cells stimulated with activated STAT3. Ginkgetin induced STAT3 dephosphorylation at Try705 and inhibited its localization to the nucleus, leading to the inhibition of expression of STAT3 target genes such as cell survival-related genes (cyclin D1 and survivin) and anti-apoptotic proteins (Bcl-2 and Bcl-xL). Therefore, ginkgetin inhibited the growth of STAT3-activated tumor cells. We also found that ginkgetin inhibited tumor growth in xenografted nude mice and downregulated p-STAT3(Tyr705) and survivin in tumor tissues. This is the first report that ginkgetin exerts antitumor activity by inhibiting STAT3. Therefore, ginkgetin is a good STAT3 inhibitor and may be a useful lead molecule for development of a therapeutic STAT3 inhibitor.

• Authors: Yoon Jung Jeon, Seung-Nam Jung, Jieun Yun, Chang Woo Lee, Jiyeon Choi, Yu-Jin Lee, Dong Cho Han, Byoung-Mog Kwon
• Journal: Cancer science (Cancer Sci) Vol. 106 Issue 4 Pg. 413-20 (Apr 2015) ISSN: 1349-7006 [Electronic] England
• PMID: 25611086 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Chemical References

• Antineoplastic Agents
• Biflavonoids
• Birc5 protein, mouse
• CCND1 protein, human
• IL6 protein, human
• Inhibitor of Apoptosis Proteins
• Interleukin-6
• Proto-Oncogene Proteins c-bcl-2
• Repressor Proteins
• STAT3 Transcription Factor
• STAT3 protein, human
• Survivin
• Cyclin D1
• ginkgetin

Topics

• Active Transport, Cell Nucleus (drug effects)
• Animals
• Antineoplastic Agents (therapeutic use)
• Apoptosis (drug effects)
• Biflavonoids (therapeutic use)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Cyclin D1 (biosynthesis)
• Drug Screening Assays, Antitumor
• Female
• G1 Phase Cell Cycle Checkpoints (drug effects)
• Ginkgo biloba (metabolism)
• HCT116 Cells
• Humans
• Inhibitor of Apoptosis Proteins (biosynthesis)
• Interleukin-6 (metabolism)
• Male
• Mice
• Mice, Inbred BALB C
• Mice, Nude
• Phosphorylation (drug effects)
• Prostate (pathology)
• Prostatic Neoplasms (drug therapy, pathology)
• Proto-Oncogene Proteins c-bcl-2 (biosynthesis)
• Repressor Proteins (biosynthesis)
• STAT3 Transcription Factor (antagonists & inhibitors, biosynthesis)
• Survivin
• Xenograft Model Antitumor Assays