title: Green tea extract inhibition of human leiomyoma cell proliferation is mediated via catechol-O-methyltransferase.
abstract: OBJECTIVE
  To investigate the inhibitory effect of green tea extract, epigallocatechin gallate (EGCG), on wild-type human leiomyoma (WT-HuLM) cells and its potential action via catechol-o-methyltransferase (COMT) activity.
  
  
  METHODS
  Cell proliferation of WT-HuLM and COMT gene-silenced HuLM (COMT-shRNA-HuLM) cells treated with 0 or 100 µM EGCG for 7 days was measured using the MTT method. Total RNA and protein were extracted from cells treated with 0 or 100 µM of EGCG for 48 h. Gene expression profiling was performed using Human Signal Transduction PathwayFinder. Proliferation cell nuclear antigen (PCNA), cyclin-dependent kinase 4 (Cdk4) and COMT protein levels were detected by Western blot analyses. COMT enzyme activity was evaluated by HPLC.
  
  
  RESULTS
  EGCG-treated WT-HuLM cells showed significantly decreased COMT expression (p < 0.001) and enzyme activity (p < 0.05) compared to untreated WT-HuLM cells, while COMT-shRNA-HuLM cells showed no significant change. At 100 μM of EGCG, survival of WT-HuLM cells was significantly lower (p < 0.05) compared to COMT-shRNA-HuLM cells. EGCG treatment modulated multiple signaling pathways in WT-HuLM compared to untreated control, while changes were minimal or reversed in COMT-shRNA-HuLM cells. EGCG significantly decreased PCNA, Cdk4 and soluble COMT protein levels (p < 0.001) in WT-HuLM, but not in COMT-shRNA-HuLM cells.
  
  
  CONCLUSIONS
  The antiproliferative and gene-modulating effects of EGCG on HuLM cells are mediated, at least partially, via its effect on COMT expression and enzyme activity.
authors.affiliation: Center for Women's Health Research, Meharry Medical College, Nashville, Tenn., USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
authors.forename: Veera
authors.initials: V
authors.lastname: Rajaratnam
authors.forename: Omar
authors.initials: O
authors.lastname: Al-Hendy
authors.forename: Sunil
authors.initials: S
authors.lastname: Halder
authors.forename: Ayman
authors.initials: A
authors.lastname: Al-Hendy
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002394:Catechol O-Methyltransferase / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D051358:Cyclin-Dependent Kinase 4 / Q000032:analysis; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D020868:Gene Silencing; D006801:Humans; D007889:Leiomyoma / Q000473:pathology*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D034741:RNA, Small Interfering; D015398:Signal Transduction; D013662:Tea / Q000737:chemistry*; D014594:Uterine Neoplasms / Q000473:pathology*
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D034741:RNA, Small Interfering; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; D002394:Catechol O-Methyltransferase; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4