title: The orphan receptor COUP-TFII regulates G2/M progression of breast cancer cells by modulating the expression/activity of p21(WAF1/CIP1), cyclin D1, and cdk2.
abstract: The orphan receptors COUP-TFI and COUP-TFII play an important role in development and differentiation by activating specific genes and by modulating the activity of nuclear receptors including estrogen receptor alpha (ERalpha) and retinoic acid receptors (RARs). Previously, it was demonstrated that the expression and activity of ERalpha and RARs are lost or impaired in anti-estrogen-resistant breast cancers. Here we show that, similar to ERalpha and RARs, the expression of COUP-TFII but not COUP-TFI is reduced in approximately 30% of breast cancer cell lines. Introduction of COUP-TFII to MDA-MB-435 cells resulted in reduced growth and plating efficiency. Interestingly, COUP-TFII increased the expression of cyclin D1 and p21(WAF1/CIP1) in MDA-MB-435 cells. Although parental and COUP-TFII-transduced cells progressed through the G1-S phase at a similar rate, progression of COUP-TFII cells through the G2/M transition phase was delayed. The activity of cdk2 required for G2/M progression was reduced in COUP-TFII cells compared to parental cells. This property of COUP-TFII is distinct from that of ERalpha and RARs, which usually modulate the G1 phase of breast cancer cells. Furthermore, these results reveal an important physiological function of COUP-TFII, which correlates with its ability to induce gene expression rather than modulation of nuclear receptor activity.
authors.affiliation: Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA. hnakshat@iupui.edu
authors.forename: H
authors.initials: H
authors.lastname: Nakshatri
authors.forename: M S
authors.initials: MS
authors.lastname: Mendonca
authors.forename: P
authors.initials: P
authors.lastname: Bhat-Nakshatri
authors.forename: N M
authors.initials: NM
authors.lastname: Patel
authors.forename: R J
authors.initials: RJ
authors.lastname: Goulet
authors.forename: K
authors.initials: K
authors.lastname: Cornetta
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D042846:CDC2-CDC28 Kinases; D051837:COUP Transcription Factor II; D051836:COUP Transcription Factors; D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism*; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D005260:Female; D016195:G2 Phase; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007700:Kinetics; D008938:Mitosis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D042846:CDC2-CDC28 Kinases; D051837:COUP Transcription Factor II; D051836:COUP Transcription Factors; D019938:Cyclin D1; D051357:Cyclin-Dependent Kinase 2; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases; D016213:Cyclins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D017346:Protein Serine-Threonine Kinases; D011987:Receptors, Steroid; D014157:Transcription Factors; C493956:CDKN1A protein, human; C495894:CDK2 protein, human; C095569:NR2F2 protein, human