Screening the active constituents of Chinese medicinal herbs as potent inhibitors of Cdc25 tyrosine phosphatase, an activator of the mitosis-inducing p34cdc2 kinase.
OBJECTIVE
To screen and evaluate the active constituents of Chinese medicinal herbs as potent inhibitors of Cdc25 phosphatase.


METHODS
The affinity chromatography purified glutashione-S-transferase/Cdc25A phosphatase fusion protein and Cdc2/cyclin B from the extracts of starfish M phase oocytes are used as the cell cycle-specific targets for screening the antimitotic constituents. We tested 9 extracts isolated from the Chinese medicinal herbs and vegetables including the agents currently used in cancer treatment by measuring the inhibition of Cdc25A phosphatase and Cdc2 kinase activity. The antitumor activity of the extracts was also evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and flow cytometry.


RESULTS
Cdc25A inhibitory activity and antitumor activity are detected in the extracts isolated from three Chinese medicinal herbs Agrimona pilosa; Herba solani lyrati; Galla chinesis.


CONCLUSIONS
We found three extracts isolated from Chinese medicinal herbs have potential inhibitory activity of Cdc25 phosphatase using a highly specific mechanism-based screen assay for antimitotic drug discovery.
Cancer Institute, Zhejiang University, Hangzhou, China. YangH@moffitt.usf.edu
Hua
H
Yang
Shu
S
Zheng
Laurent
L
Meijer
Shi-min
SM
Li
Sophie
S
Leclerc
Lin-lin
LL
Yu
Jin-quan
JQ
Cheng
Su-zhan
SZ
Zhang
D017209:Apoptosis / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D045744:Cell Line, Tumor; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000032:analysis / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D007928:Lethal Dose 50; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology; D008516:Medicine, Chinese Traditional / Q000379:methods; D008938:Mitosis / Q000187:drug effects*; D008517:Phytotherapy / Q000379:methods; D010946:Plants, Medicinal / Q000737:chemistry; D020687:cdc25 Phosphatases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000095043:Cyclin-Dependent Kinase-Activating Kinase
D018797:Cell Cycle Proteins; D004365:Drugs, Chinese Herbal; D018844:Cyclin-Dependent Kinases; C517008:CDC25B protein, human; D020687:cdc25 Phosphatases; D000095043:Cyclin-Dependent Kinase-Activating Kinase