Toko T, Shibata J, Nukatsuka M, Yamada Y
Hanno Research Center, Taiho Pharmaceutical Co. Ltd., Saitama, Japan.
Cancer Chemother Pharmacol. 1997;39(5):390-8. doi: 10.1007/s002800050589.
The purpose of this study was to clarify the mechanism(s) of antiestrogenic action of DP-TAT-59 ((Z)-2-(4-(1-(4-hydroxyphenyl)-2-(4-isopropyl-phenyl)- 1-butenyl)phenoxy)-N,N-dimethylethylamine), the main active metabolite of TAT-59.
Using 4-OH-tamoxifen (a hydroxylated metabolite of tamoxifen) as a reference compound, we examined the relationship between hormone-dependent tumor cells and DP-TAT-59 and characterized estrogen receptor (ER) complexes with DP-TAT-59 using ion-exchange chromatography.
DP-TAT-59 inhibited the in vitro proliferation of MCF-7 cells under serum-free conditions at a lower concentration than did 4-OH-tamoxifen. The conditioned medium (CM) obtained from the culture supernatant of MCF-7 cells in the presence of these antiestrogens suppressed the growth of ER-negative cell lines, but that from ER-negative human mammary carcinoma MX-1 cells did not. The CM from DP-TAT-59-treated cells showed a higher growth-inhibitory potency against human mammary carcinoma ZR-75-1 cells than did that from 4-OH-tamoxifen-treated cells. The growth-inhibitory potency of the CM was neutralized by the addition of the anti-TGF-beta antibody. The CM obtained from cells treated with DP-TAT-59 contained more TGF-beta and less TGF-alpha than that treated with 4-OH-tamoxifen. As the antiestrogenic activity of TAT-59 might be mediated through ER, the interaction of these antiestrogens with a cytoplasmic receptor of MCF-7 cells was examined. While the competitive binding of [3H]-estradiol with these antiestrogens to ER was similar, ER complexes with DP-TAT-59 showed a different elution profile by ion-exchange chromatography, indicating that DP-TAT-59 formed a different complex with ER from either 4-OH-tamoxifen or estradiol.
These findings suggest that at least a part of the growth suppressive ability of DP-TAT-59 against human mammary carcinoma might depend on the production of growth inhibitory factors and/or the suppression of production of growth factors from ER-positive cells, and that the production of growth inhibitory factors might be stimulated by ER complexes with antiestrogens rather than with estrogen.
本研究旨在阐明TAT-59的主要活性代谢产物DP-TAT-59（(Z)-2-(4-(1-(4-羟基苯基)-2-(4-异丙基苯基)-1-丁烯基)苯氧基)-N,N-二甲基乙胺）的抗雌激素作用机制。
以4-羟基他莫昔芬（他莫昔芬的羟基化代谢产物）作为参考化合物，我们研究了激素依赖性肿瘤细胞与DP-TAT-59之间的关系，并使用离子交换色谱法对DP-TAT-59与雌激素受体（ER）复合物进行了表征。
在无血清条件下，DP-TAT-59以低于4-羟基他莫昔芬的浓度抑制MCF-7细胞的体外增殖。在这些抗雌激素存在的情况下，从MCF-7细胞培养上清液中获得的条件培养基（CM）抑制ER阴性细胞系的生长，但来自ER阴性人乳腺癌MX-1细胞的CM则无此作用。与4-羟基他莫昔芬处理的细胞相比，DP-TAT-59处理的细胞的CM对人乳腺癌ZR-75-1细胞显示出更高的生长抑制效力。通过添加抗TGF-β抗体可中和CM的生长抑制效力。与4-羟基他莫昔芬处理的细胞相比，DP-TAT-59处理的细胞获得的CM含有更多的TGF-β和更少的TGF-α。由于TAT-59的抗雌激素活性可能通过ER介导，因此研究了这些抗雌激素与MCF-7细胞胞质受体的相互作用。虽然[3H]-雌二醇与这些抗雌激素与ER的竞争性结合相似，但DP-TAT-59与ER的复合物在离子交换色谱中显示出不同的洗脱图谱，表明DP-TAT-59与ER形成的复合物与4-羟基他莫昔芬或雌二醇均不同。
这些发现表明，DP-TAT-59对人乳腺癌的生长抑制能力至少部分可能取决于生长抑制因子的产生和/或ER阳性细胞生长因子产生的抑制，并且生长抑制因子的产生可能由抗雌激素而非雌激素与ER的复合物刺激。
