药物治疗浓度的雌激素对卵巢癌3AO细胞生长的影响

在过去的20年里，人们对于雌激素在不同组织、器官中发挥不同功能的分子机制进行了深入的研究，并取得了非常快的进展。最近的研究表明，雌激素能够抑制包括卵巢癌在内的多种肿瘤细胞的生长。卵巢是女性雌激素的主要来源，多种卵巢细胞表达雌激素受体，其中包括90％以上的卵巢癌起源的卵巢表面上皮细胞。雌激素诱导卵巢癌细胞凋亡的研究非常有实验及临床价值，雌激素调控的凋亡相关的特异性基因的发现对于揭示卵巢癌的发生发展以及针对卵巢癌特异性治疗的研究将会提供巨大的帮助。以人卵巢癌3AO细胞为模型，探讨了药物治疗浓度的雌激素对卵巢癌细胞的凋亡诱导作用以及其可能机制。首先用MTT检测方法观察了雌二醇及其受体拮抗剂ICI 182780对3AO细胞生长的影响。研究发现，高于0．1pmol／L浓度的雌二醇能够抑制3AO细胞的生长，其中5pmol／L浓度的雌二醇处理3AO细胞72h后，对3AO细胞的抑制率达到70％。雌激素受体的拮抗剂ICI 182780不但不能阻断雌激素的效应，它本身也能抑制3AO细胞的生长，并且与雌激素有协同效应，并且经流式细胞术证实雌激素及其受体拮抗剂引起的3AO细胞的死亡为凋亡。雌激素对生长的调控是细胞类型特异性的，其机制可能与细胞内雌激素受体不同亚型的表达有关。细胞内雌激素受体β亚型的表达利于细胞凋亡的发生，细胞内雌激素受体α亚型的表达则会保护细胞免于凋亡的发生。在对雌激素诱导的凋亡发生机制的探讨过程中，我们发现3AO细胞只表达雌激素受体β亚型，而不表达雌激素受体α亚型，并且与α亚型相比，β亚型的表达明显降低，这可以解释为何需要高浓度的雌激素才能够诱导3AO细胞凋亡。我们又观察了大分子BSA标记的雌激素对3AO细胞生长的影响，结果发现这种不能通过细胞膜的雌激素失去了对3AO细胞生长的抑制作用，从而排除了雌激素的膜效应。近来的研究表明，MAPK信号通路在调控细胞的生长过程中发挥了重要的作用，并且参与了雌激素调控细胞生长的过程。接下来我们观察了MAPK信号通路在雌激素诱导3AO细胞生长中的作用。研究发现，p38／MAPK激酶的抑制剂SB203580部分的阻断了雌激素的生长抑制效应，而JNK／MAPK激酶的抑制剂SP600125则能促进雌激素的效应，提示MAPK信号通路参与了雌激素的这种效应。

Effects of Pharmacological Concentrations of Estrogens on Growth of 3AO Human Ovarian Cancer Cells

During the past two decades, the knowledge of the molecular mechanism by which estrogens exert various functions in different tissues and organs has evolved rapidly. Recent reports demonstrated that estrogen could decrease the cell growth in several types of cancer cells, including ovarian cancer cells. Though experiments explored the possible mechanism of the inhibitory effect, the exact mechanism is responsible for the effect, which remains unclear. The ovary is the main source of the estrogen, estrogen receptor is expressed in several ovarian cell types, including ovarian surface epithelium, the tissue of origin of approximately 90% of the ovarian cancers. It was of great interest to analyze the effects of 17β-estradlol (E2) on apoptosis of ovarian cancer cells, and the identification of E2-regnlated specific genes involved in epithelial proliferation apoptosis, thus may be a clue for understanding the progression of ovarian cancer and for the design of new target therapies. To elucidate the mechanism involved, effects of pharmacological concentrations of estrogen were studied in human ovarian cancer cell line 3AO cells. Inhibition of cellular growth of 3AO cells was seen with E2 at concentrations higher than 0.1μmol/L. The estrogen receptor inhibitor ICI 182780 cannot block the inhibitory effect of E2. It was surprising to find that ICI 182780 itself can inhibit the growth of 3AO cells, and had a collaborative effect with E2. The decreased cell growth induced by E2 was shown to be apoptosis as analyzed by flow cytometry. ERβ was detected in the 3AO ovarian cancer cell line but not ERα. The expression of ERβ was weak, which may partially explain why high but not low dose of E2 needed to induce the apoptosis of 3AO cells. We also observed that membrane impermeable E2, E2-BSA have lost growth inhibitory on 3AO cells, which excluded the membrane effect of E2 as previously reported by many investigators. The p38 kinase inhibitor, SB203580 were partially protected 3AO cells against growth inhibition by E2, while inhibitor of JNK, SP600125 enhanced cell death induced by E2. These results showed that MAPK is implicated in cellular processes involving apoptosis.