Eupatilin, a pharmacologically active flavone derived from Artemisia plants, induces cell cycle arrest in ras-transformed human mammary epithelial cells.
Extracts of Artemisia asiatica Nakai (Asteraceae) possess anti-inflammatory and anti-oxidative activities. Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone), one of the pharmacologically active ingredients derived from A. asiatica, was shown to induce apoptosis in human promyelocytic leukemia (HL-60) cells [Mutat Res 496 (2001) 191]. In the present study, we examined the cytostatic effects of eupatilin in H-ras-transformed human breast epithelial (MCF10A-ras) cells. Eupatilin inhibited the growth of MCF10A-ras cells in a concentration-dependent and time-related manner. To explore whether the anti-proliferative effects of eupatilin could be mediated through modulation of the cell cycle in MCF10A-ras, DNA contents were analyzed by the flow cytometry. Eupatilin inhibited the expression of cyclin D1, cyclin B1, Cdk2 and Cdc2 that are key regulators of the cell cycle. In addition, eupatilin treatment led to elevated expression of p53 and p27Kip1 that act as Cdk inhibitors. It has been known that the Ras-signaling pathway plays integral roles in the induction of cyclin D1. Eupatilin inhibited the activation of ERK1/2 as well as expression of Raf-1 and Ras in MCF10A-ras cells. Thus, the inhibitory effect of eupatilin on cyclin D1 expression appears to be mediated by targeting the Raf/MEK/ERK signaling cascades. Eupatilin did not change activation of Akt, an important component of cell-survival pathways. In conclusion, the anti-proliferative effect of eupatilin in MCF10A-ras cells is associated with its blockade of cell cycle progression which appears to be attributable in part to inhibition of ERK1/2 activation.
Laboratory of Biochemistry and Molecular Toxicology, College of Pharmacy, Seoul National University, Shinlim-dong, Kwanak-ku, 151-742, South Korea.
Do-Hee
DH
Kim
Hye-Kyung
HK
Na
Tae Young
TY
Oh
Won-Bae
WB
Kim
Young-Joon
YJ
Surh
D019306:Artemisia / Q000737:chemistry*; D002453:Cell Cycle / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002471:Cell Transformation, Neoplastic; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects*; D047309:Flavones; D005419:Flavonoids / Q000494:pharmacology*; D016193:G1 Phase / Q000187:drug effects; D011905:Genes, ras / Q000502:physiology; D018922:HL-60 Cells; D006801:Humans; D042361:Mammary Glands, Human / Q000166:cytology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D016196:S Phase / Q000187:drug effects; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
D018797:Cell Cycle Proteins; D047309:Flavones; D005419:Flavonoids; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D019938:Cyclin D1; D050760:Cyclin-Dependent Kinase Inhibitor p27; C045325:eupatilin; D019908:Proto-Oncogene Proteins c-raf; D018844:Cyclin-Dependent Kinases; D020928:Mitogen-Activated Protein Kinases; C043562:flavone