Bursch W, Ellinger A, Kienzl H, Török L, Pandey S, Sikorska M, Walker R, Hermann R S
Institut für Tumorbiologie-Krebsforschung der Universität Wien, Austria.
Carcinogenesis. 1996 Aug;17(8):1595-607. doi: 10.1093/carcin/17.8.1595.
Active cell death in hormone-dependent cells was studied using cultured human mammary carcinoma cells (MCF-7) treated with the anti-estrogens (AEs) tamoxifen (TAM), 4-hydroxy-tamoxifen (OH-TAM) or ICI 164 384 (10(-8)-10(-5) M) as a model. The following results were obtained. (i) In untreated MCF-7 cells a wave of replication occurred in the first 5 days of culture. All three AEs caused a dose-dependent inhibition of cell replication. (ii) TAM and OH-TAM at 10(-5) M, but not ICI 164 384, caused lytic cell death (necrosis) within 24 h, which was not inhibited by estradiol (10(-9)-10(-6)M). (iii) Lower concentrations of TAM or OH-TAM (up to 10(-6) M) or ICI 164 384 induced a more gradual appearance of cell death beginning at day 3. This type of cell death was inhibited by estradiol (10(-9) M), indicating its active nature. (iv) Nuclei showed two distinct patterns of alteration: (a) apoptosis-like condensation and fragmentation of chromatin to crescent masses abutting the nuclear envelope; (b) condensation of the chromatin to a single, pyknotic mass in the center of the nucleus, detached from the nuclear envelope. Quantitative histological evaluation revealed the predominance of pyknosis. (v) Biochemical DNA analysis revealed that only a relatively small amount of the total DNA was finally degraded into low molecular weight fragments (20 kb and less). (vi) Active cell death, with both apoptotic and pyknotic nuclear morphology, was associated with extensive formation of autophagic vacuoles (AV).3-Methyladenine, a known inhibitor of AV formation, partially prevented cell death as detected by nuclear changes. (vii) ICI 164 384 was about 10 times more effective than TAM or OH-TAM at inhibiting DNA synthesis, but had equal potency in inducing active cell death. It is concluded that AEs have anti-proliferative and anti-survival effects on MCF-7 human mammary cancer cells in culture. These two effects are under separate control because they differ by kinetics, dose dependence and sensitivity to the various AEs. Active cell death in MCF-7 cells seems to be initiated by autophagy, in contrast to concepts of apoptosis, and thus corresponds to autophagic/ lysosomal or type II death as previously defined. This may be important because of biochemical and molecular differences between these various subtypes of active cell death.
以培养的人乳腺癌细胞（MCF-7）为模型，用抗雌激素药物（AE）他莫昔芬（TAM）、4-羟基他莫昔芬（OH-TAM）或ICI 164 384（10⁻⁸ - 10⁻⁵ M）处理，研究激素依赖性细胞中的活性细胞死亡。得到以下结果。（i）在未处理的MCF-7细胞中，培养的前5天出现一轮复制。所有三种AE均引起细胞复制的剂量依赖性抑制。（ii）10⁻⁵ M的TAM和OH-TAM，但ICI 164 384不会，在24小时内引起溶解性细胞死亡（坏死），这不受雌二醇（10⁻⁹ - 10⁻⁶ M）的抑制。（iii）较低浓度的TAM或OH-TAM（高达10⁻⁶ M）或ICI 164 384从第3天开始诱导细胞死亡逐渐出现。这种类型的细胞死亡受雌二醇（10⁻⁹ M）抑制，表明其活性性质。（iv）细胞核显示出两种不同的变化模式：（a）染色质呈凋亡样凝聚和碎片化，形成新月形团块紧靠核膜；（b）染色质凝聚成单个固缩团块位于细胞核中央，与核膜分离。定量组织学评估显示固缩占优势。（v）生化DNA分析表明，最终只有相对少量的总DNA降解为低分子量片段（20 kb及以下）。（vi）具有凋亡和固缩核形态的活性细胞死亡与自噬泡（AV）的大量形成有关。3-甲基腺嘌呤，一种已知的AV形成抑制剂，通过核变化检测部分阻止了细胞死亡。（vii）ICI 164 384在抑制DNA合成方面比TAM或OH-TAM有效约10倍，但在诱导活性细胞死亡方面效力相当。结论是AE对培养的MCF-7人乳腺癌细胞具有抗增殖和抗存活作用。这两种作用受不同控制，因为它们在动力学、剂量依赖性和对各种AE的敏感性方面存在差异。与凋亡概念相反，MCF-7细胞中的活性细胞死亡似乎由自噬引发，因此对应于先前定义的自噬/溶酶体或II型死亡。由于这些活性细胞死亡不同亚型之间的生化和分子差异，这可能很重要。
