Tamoxifen induction of CCAAT enhancer-binding protein α is required for tamoxifen-induced apoptosis

被引:13
作者
Cheng, Jingwei [1 ]
Yu, David V. [1 ]
Zhou, Jian-Hua [1 ]
Shapiro, David J. [1 ]
机构
[1] Univ Illinois, Dept Biochem, Urbana, IL 61801 USA
关键词
D O I
10.1074/jbc.M704829200
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Low concentrations of tamoxifen or its active metabolite 4-hydroxytamoxifen (OHT) induce estrogen receptor alpha(ER alpha)-dependent apoptosis. To analyze the pathway of OHT-ER alpha-induced apoptosis, we developed stably transfected lines of HeLa cells expressing wild-type ER and an inactive mutant ER alpha unable to bind estrogen response elements. HeLa cells expressing the mutant ER alpha and HeLa cells expressing wild-type ER alpha in which the ER was knocked down with an ER-specific small interfering RNA were not killed by Tam or OHT, suggesting that estrogen response element-mediated transcription is required for Tam- and OHT-induced apoptosis. Microarray analysis to identify a gene(s) whose expression is important in OHT-ER-mediated apoptosis identified 19 mRNAs that OHT up-regulated by > 1.6-fold and 15 down-regulated mRNAs. Gene function and the time course of induction by OHT-ER alpha led us to further investigate CCAAT enhancer-binding protein alpha (C/EBP alpha), which has roles in cell cycle progression and apoptosis, and p21. Quantitative reverse transcription-PCR, Western blot analysis, and RNA interference knockdown suggest that cell cycle arrest resulting from OHT-ER alpha induction of p21 may facilitate apoptosis. OHT-ER alpha, but not E-2-ER alpha, induced C/EBP alpha mRNA and protein. RNA interference knockdown of C/EBP alpha nearly abolished OHT-ER alpha-induced apoptosis. We isolated stable cell lines that were resistant to OHT-induced apoptosis, contain full-length functional ER alpha, and undergo apoptosis in response to etoposide. In these OHT-resistant cell lines both before and after OHT treatment, C/EBP alpha levels are much lower than in OHT-sensitive cells. These studies establish a novel molecular site responsible for Tam- and OHT-ER alpha-induced apoptosis of cancer cells.
引用
收藏
页码:30535 / 30543
页数:9
相关论文
共 59 条
[51]   Identification of a functional imperfect estrogen-responsive element in the 5'-promoter region of the human cathepsin D gene [J].
Wang, F ;
Porter, W ;
Xing, W ;
Archer, TK ;
Safe, S .
BIOCHEMISTRY, 1997, 36 (25) :7793-7801
[52]   C/EBPα arrests cell proliferation through direct inhibition of cdk2 and cdk4 [J].
Wang, HM ;
Iakova, P ;
Wilde, M ;
Welm, A ;
Goode, T ;
Roesler, WJ ;
Timchenko, NA .
MOLECULAR CELL, 2001, 8 (04) :817-828
[53]   TAMOXIFEN ACTIVATION OF THE ESTROGEN RECEPTOR/AP-1 PATHWAY - POTENTIAL ORIGIN FOR THE CELL-SPECIFIC ESTROGEN-LIKE EFFECTS OF ANTIESTROGENS [J].
WEBB, P ;
LOPEZ, GN ;
UHT, RM ;
KUSHNER, PJ .
MOLECULAR ENDOCRINOLOGY, 1995, 9 (04) :443-456
[54]   THE TRANSCRIPTIONAL ACTIVATION FUNCTION LOCATED IN THE HORMONE-BINDING DOMAIN OF THE HUMAN ESTROGEN-RECEPTOR IS NOT ENCODED IN A SINGLE EXON [J].
WEBSTER, NJG ;
GREEN, S ;
TASSET, D ;
PONGLIKITMONGKOL, M ;
CHAMBON, P .
EMBO JOURNAL, 1989, 8 (05) :1441-1446
[55]   THE HORMONE-BINDING DOMAINS OF THE ESTROGEN AND GLUCOCORTICOID RECEPTORS CONTAIN AN INDUCIBLE TRANSCRIPTION ACTIVATION FUNCTION [J].
WEBSTER, NJG ;
GREEN, S ;
JIN, JR ;
CHAMBON, P .
CELL, 1988, 54 (02) :199-207
[56]  
Williams SC, 1997, GENE EXPRESSION, V6, P371
[57]  
XU LX, 1994, CHINESE MED J-PEKING, V107, P596
[58]   HMG-1 stimulates estrogen response element binding by estrogen receptor from stably transfected HeLa cells [J].
Zhang, CC ;
Krieg, S ;
Shapiro, DJ .
MOLECULAR ENDOCRINOLOGY, 1999, 13 (04) :632-643
[59]  
Zhang GJ, 1999, CLIN CANCER RES, V5, P2971