The flavonoid eupatorin inactivates the mitotic checkpoint leading to polyploidy and apoptosis.

Abstract

The spindle assembly checkpoint (SAC) is a conserved mechanism that ensures the fidelity of chromosome distribution in mitosis by preventing anaphase onset until the correct bipolar microtubule-kinetochore attachments are formed. Errors in SAC function may contribute to tumorigenesis by inducing numerical chromosome anomalies (aneuploidy). On the other hand, total disruption of SAC can lead to massive genomic imbalance followed by cell death, a phenomena that has therapeutic potency. We performed a cell-based high-throughput screen with a compound library of 2000 bioactives for novel SAC inhibitors and discovered a plant-derived phenolic compound eupatorin (3',5-dihydroxy-4',6,7-trimethoxyflavone) as an anti-mitotic flavonoid. The premature override of the microtubule drug-imposed mitotic arrest by eupatorin is dependent on microtubule-kinetochore attachments but not interkinetochore tension. Aurora B kinase activity, which is essential for maintenance of normal SAC signaling, is diminished by eupatorin in cells and in vitro providing a mechanistic explanation for the observed forced mitotic exit. Eupatorin likely has additional targets since eupatorin treatment of pre-mitotic cells causes spindle anomalies triggering a transient M phase delay followed by impaired cytokinesis and polyploidy. Finally, eupatorin potently induces apoptosis in multiple cancer cell lines and suppresses cancer cell proliferation in organotypic 3D cell culture model.

• Authors: Anna-Leena Salmela, Jeroen Pouwels, Anu Kukkonen-Macchi, Sinikka Waris, Pauliina Toivonen, Kimmo Jaakkola, Jenni Mäki-Jouppila, Lila Kallio, Marko J Kallio
• Journal: Experimental cell research (Exp Cell Res) Vol. 318 Issue 5 Pg. 578-92 (Mar 10 2012) ISSN: 1090-2422 [Electronic] United States
• PMID: 22227008 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 Elsevier Inc. All rights reserved.

Chemical References

• Antimitotic Agents
• Flavonoids
• Leupeptins
• Proteasome Inhibitors
• Pyrimidines
• Thiones
• eupatorin
• monastrol
• AURKB protein, human
• Aurora Kinase B
• Aurora Kinases
• Bub1 spindle checkpoint protein
• Protein Serine-Threonine Kinases
• Proteasome Endopeptidase Complex
• benzyloxycarbonylleucyl-leucyl-leucine aldehyde
• Nocodazole

Topics

• Antimitotic Agents (pharmacology)
• Apoptosis (drug effects)
• Aurora Kinase B
• Aurora Kinases
• Cell Culture Techniques
• Cell Proliferation (drug effects)
• Centrosome (metabolism)
• Flavonoids (pharmacology)
• HeLa Cells
• High-Throughput Screening Assays
• Humans
• Leupeptins (pharmacology)
• M Phase Cell Cycle Checkpoints (drug effects)
• Male
• Microscopy, Fluorescence
• Nocodazole (pharmacology)
• Polyploidy
• Prostatic Neoplasms
• Proteasome Endopeptidase Complex (metabolism)
• Proteasome Inhibitors
• Protein Serine-Threonine Kinases (antagonists & inhibitors, metabolism)
• Pyrimidines (pharmacology)
• Thiones (pharmacology)
• Time-Lapse Imaging