title: Antiproliferative and apoptotic effect of epigallocatechin-3-gallate             on Ishikawa cells is accompanied by sex steroid receptor downregulation.
abstract: Endometrial cancer is a significant malignancy in developed countries. Unopposed estrogen stimulation is considered as an important risk factor for endometrial cancer. Epigallocathechin-3-gallate (EGCG), biological active component of green tea, inhibits cancer cell proliferation. However, it is unknown whether EGCG has anticancer effects on endometrial cancer and what the molecular mechanism(s) are. We investigated the anticancer effects of EGCG on a human endometrial adenocarcinoma cell line (Ishikawa cells) with or without 17β-estradiol (E2) treatment. Cell proliferation assay was performed using 3-(4,5-dimethylthiaxol-2-yi)-2,5-diphenyltetraxolium bromide (MTT). The cell cycle was determined by flow cytometry and real-time analysis of cyclin and cdk genes. The apoptosis was measured by Annexin V-PI staining and real-time analysis of bcl-2, Bax and caspase genes. The MAPK signal, Akt and caspase-3 were determined by immunoblotting. Decreased estrogen and progesterone receptor expression was observed in EGCG-treated Ishikawa cells, and decreased MAPK signals and phospho-Akt were observed as well. EGCG caused the arrest of cells in the G0/G1 phase of the cell cycle. This compound interfered with Akt activation and MAPK signals, and increased apoptosis signals leading to a controlled caspases, Bcl-2, Bax genes and protein expression. Taken together, EGCG inhibits cell proliferation and induces apoptosis through Akt and MAPK signals. These findings suggest that EGCG may exert growth-inhibitory and apoptosis-inducing effects on endometrial cancer cells, accompanied by decreased estrogen and progesterone receptor. EGCG may have future clinical implications with respect to the development of novel approaches as an adjuvant therapy in endometrial cancer.
authors.affiliation: Department of Obstetrics and Gynecology, Dong-A University, College                     of Medicine, Busan 602-715, Republic of Korea.
authors.forename: Seung Bin
authors.initials: SB
authors.lastname: Park
authors.forename: Jong Woon
authors.initials: JW
authors.lastname: Bae
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Kim
authors.forename: Seung Gee
authors.initials: SG
authors.lastname: Lee
authors.forename: Myoungseok
authors.initials: M
authors.lastname: Han
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D015536:Down-Regulation / Q000187:drug effects*; D004789:Enzyme Activation; D004958:Estradiol / Q000494:pharmacology / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D020935:MAP Kinase Signaling System; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D051017:Apoptosis Regulatory Proteins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D004958:Estradiol; D002392:Catechin; C045651:epigallocatechin gallate; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D020169:Caspases