Differential effects of 16α-hydroxyestrone and 2-methoxyestradiol on cyclin D1 involving the transcription factor ATF-2 in MCF-7 breast cancer cells

TY - JOUR

T1 - Differential effects of 16α-hydroxyestrone and 2-methoxyestradiol on cyclin D1 involving the transcription factor ATF-2 in MCF-7 breast cancer cells

AU - Lewis, Joan S.

AU - Thomas, T. J.

AU - Pestell, Richard G.

AU - Albanese, Chris

AU - Gallo, Michael A.

AU - Thomas, Thresia

PY - 2005/2

Y1 - 2005/2

N2 - We studied the effects of 2-methoxyestradiol (2-ME2) and 16α-hydroxyestrone (16α-OHE1), two metabolites of estradiol (E2), on DNA synthesis, cell cycle progression and cyclin D1 protein levels in estrogen receptor-positive MCF-7 cells. E2 and 16α-OHE1 stimulated DNA synthesis, and 2-ME2 inhibited the stimulatory effects of these agents. E2 and 16α-OHE1 stimulated the progression of cells from G1 to S phase and this effect was attenuated by 2-ME2. Western blot analysis showed that E2 and 16α-OHE1 increased cyclin D1 protein level by about fourfold compared with control. 2-ME2 had no significant effect on cyclin D1; however, it prevented the accumulation of cyclin D1 in the presence of E2 and 16α-OHE1. Cells transfected with a cyclin D1 reporter gene and treated with E2 or 16α-OHE1 showed 7- and 9.5-fold increase respectively in promoter activity compared with control. This activity was significantly inhibited by 2-ME2. Cyclin D1 transactivation was mediated by the cAMP response element (CRE) region, which binds activating transcription factor 2 (ATF-2). DNA affinity assay showed 2.5- and 3.5-fold increases in ATF-2 binding to CRE in the presence of E2 and 16α-OHE1, respectively. The binding of ATF-2 was inhibited by the presence of 2-ME2. These results show that 2-ME2 can downregulate cyclin D1 and thereby cell cycle progression by a mechanism involving the disruption of ATF-2 binding to cyclin D1 promoter.

AB - We studied the effects of 2-methoxyestradiol (2-ME2) and 16α-hydroxyestrone (16α-OHE1), two metabolites of estradiol (E2), on DNA synthesis, cell cycle progression and cyclin D1 protein levels in estrogen receptor-positive MCF-7 cells. E2 and 16α-OHE1 stimulated DNA synthesis, and 2-ME2 inhibited the stimulatory effects of these agents. E2 and 16α-OHE1 stimulated the progression of cells from G1 to S phase and this effect was attenuated by 2-ME2. Western blot analysis showed that E2 and 16α-OHE1 increased cyclin D1 protein level by about fourfold compared with control. 2-ME2 had no significant effect on cyclin D1; however, it prevented the accumulation of cyclin D1 in the presence of E2 and 16α-OHE1. Cells transfected with a cyclin D1 reporter gene and treated with E2 or 16α-OHE1 showed 7- and 9.5-fold increase respectively in promoter activity compared with control. This activity was significantly inhibited by 2-ME2. Cyclin D1 transactivation was mediated by the cAMP response element (CRE) region, which binds activating transcription factor 2 (ATF-2). DNA affinity assay showed 2.5- and 3.5-fold increases in ATF-2 binding to CRE in the presence of E2 and 16α-OHE1, respectively. The binding of ATF-2 was inhibited by the presence of 2-ME2. These results show that 2-ME2 can downregulate cyclin D1 and thereby cell cycle progression by a mechanism involving the disruption of ATF-2 binding to cyclin D1 promoter.

UR - http://www.scopus.com/inward/record.url?scp=14544273363&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=14544273363&partnerID=8YFLogxK

U2 - https://doi.org/10.1677/jme.1.01599

DO - https://doi.org/10.1677/jme.1.01599

M3 - Article

C2 - 15691880

VL - 34

SP - 91

EP - 105

JO - Journal of Molecular Endocrinology

JF - Journal of Molecular Endocrinology

SN - 0952-5041

IS - 1

ER -