Effect of long-term estrogen deprivation on apoptotic responses of breast cancer cells to 17β-estradiol
Effect of long-term estrogen deprivation on apoptotic responses of breast cancer cells to 17β-estradiol
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DOI：
10.1093/jnci/93.22.1714
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发表时间：
2001-11-21
期刊：
影响因子：
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通讯作者：
Santen, RJ
中科院分区：
文献类型：
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作者：
Song, RXD;Mor, G;Santen, RJ
背景资料：高剂量雌激素可以促进绝经后妇女乳腺癌的肿瘤消退，但其机制尚不清楚。我们通过使用LTED细胞研究了这一过程的分子基础，LTED细胞是通过在长期（6-24个月）雌激素剥夺条件下生长MCF-7乳腺癌细胞而获得的。研究方法：我们用不同浓度的17 β-雌二醇（雌二醇）处理LTED和MCF-7细胞，并通过计数细胞来测定它们的生长，并通过膜联蛋白V染色和DNA片段化来测量凋亡。使用蛋白质印迹分析，我们还研究了Fas死亡受体蛋白及其配体FasL在这些细胞中的凋亡诱导系统的表达。为了评估Fas和FasL在LTED细胞中诱导凋亡的参与，我们使用了激活性抗Fas抗体和通用半胱天冬酶抑制剂Z-VAD。最后，我们研究了Fas蛋白在E8 CASS和BSK 3细胞中的表达，这两种细胞系是通过长期剥夺MCF-7细胞的雌激素而获得的，以及这些细胞对高剂量雌二醇的反应：所有统计检验都是双侧的。结果如下：高浓度的雌二醇（大于或等于0.1 nM）导致LTED细胞生长统计学显著降低60%（P <0.001），与载体处理的细胞相比，凋亡增加7倍（P <0.001）。LTED和MCF-7细胞均表达FasL，但仅LTED细胞表达Fas。用0.1 nM雌二醇处理LTED细胞增加了FasL的表达。激活抗Fas抗体增加LTED细胞的凋亡，这是进一步刺激雌二醇。Z-VAD阻断雌二醇诱导的细胞凋亡。表达Fas蛋白的E8 CASS细胞，而不是不表达Fas蛋白的BSK 3细胞，也通过增加凋亡对0.1 nM雌二醇作出反应。结论：大剂量雌激素治疗诱导绝经后妇女肿瘤消退可能与雌激素激活Fas介导的凋亡有关。
Background: High doses of estrogen can promote tumor regression in postmenopausal women with hormone-dependent breast cancer, but the mechanism is unknown. We investigated the molecular basis of this process by using LTED cells, which were derived by growing MCF-7 breast cancer cells under long-term (6-24 months) estrogen-deprived conditions. Methods: We treated LTED and MCF-7 cells with various concentrations of 17 beta -estradiol (estradiol) and assayed their growth by counting the cells and measured apoptosis by annexin V staining and DNA fragmentation. Using western blot analysis, we also examined the expression of the apoptosis-inducing system of the Fas death receptor protein and its ligand, FasL, in these cells. To assess the involvement of Fas and FasL in the induction of apoptosis in LTED cells, we used activating anti-Fas antibodies and the universal caspase inhibitor Z-VAD. Finally, we examined the expression of Fas protein in E8CASS and BSK3 cells, two other cell lines derived by depriving MCF-7 cells of estrogen long term, and the responses of these cells to high-dose estradiol: All statistical tests were two-sided. Results: High concentrations of estradiol (greater than or equal to0.1 nM) resulted in a statistically significant, 60% reduction in the growth of LTED cells (P < .001) and in a sevenfold increase in apoptosis (P < .001) as compared with levels in vehicle-treated cells. Both LTED and MCF-7 cells expressed FasL, but only LTED cells expressed Fas. Treatment of LTED cells with 0.1 nM estradiol increased the expression of FasL. Activating anti-Fas antibodies increased apoptosis of LTED cells, which was further stimulated by estradiol. Z-VAD blocked estradiol-induced apoptosis. E8CASS cells, which express Fas protein, but not BSK3 cells, which do not, also responded to 0.1 nM estradiol by increasing apoptosis. Conclusion: Tumor regression induced by high-dose estrogen therapy in postmenopausal woman may result from estrogen activation of Fas-mediated apoptosis.