槲皮素的植物雌激素作用及其受体机制研究

目的:探讨槲皮素(quercetin,Que)的植物雌激素作用及其可能的受体作用机制.方法:采用噻唑蓝(MTT)比色法测定槲皮素对雌激素依赖性乳腺癌细胞T47D和非雌激素依赖性乳腺癌细胞MDA-MB231的细胞增殖作用,流式细胞术对T47D细胞的增殖情况进行分析.Western blot方法测定槲皮素对T47D细胞雌激素受体两种亚型ERα和ERβ表达的影响,并以雌激素受体拮抗剂ICI182,780为工具药来评价槲皮素发挥雌激素样作用与雌激素受体的关系.结果:与溶剂对照组相比较,槲皮素(10,20,40 μmol·L^-1) 能显著促进T47D细胞的增殖,而抑制雌激素受体阴性MDA-MB231细胞,并将T47D细胞周期由G₁期向S期推进,促进DNA合成,提高细胞分裂增殖指数;且槲皮素促进T47D细胞增殖作用被雌激素受体拮抗剂所拮抗,槲皮素在10 μmol·L^-1可明显诱导T47D细胞ERα蛋白表达,而对ERβ表达没有影响.当与ICI 182,780共孵育T47D细胞ERα表达被拮抗.结论:槲皮素具有雌激素活性,此作用是通过影响雌激素受体ERα蛋白表达介导的.     

补骨脂素对人类乳腺癌细胞增殖作用的影响

目的研究补骨脂素(psoralen,Pso)对人类乳腺癌细胞株增殖的影响。方法采用噻唑蓝(MTT)比色法测定补骨脂素对雌激素依赖性乳腺癌细胞MCF-7和非雌激素依赖性乳腺癌细胞MDA-MB231的细胞增殖作用,并以雌激素受体拮抗剂ICI182,780为工具药来评价补骨脂素发挥雌激素样作用与雌激素受体的关系,流式细胞术对MCF-7细胞的增殖情况进行分析。结果与溶剂对照组相比较,Pso(10～40μmol.L-1)能明显促进MCF-7细胞的增殖,而对雌激素受体阴性MDA-MB231细胞未见影响,并将MCF-7细胞周期由G1期向S期推进,促进DNA合成,提高细胞分裂增殖指数,且Pso促进MCF-7细胞增殖作用被雌激素受体拮抗剂所拮抗。结论补骨脂素具有雌激素活性,此作用是通过雌激素受体(ER)介导的。     

槲皮素、补骨脂素对乳腺癌细胞株MCF-7增殖的影响

目的探讨槲皮素(quercetin,Que)和补骨脂素(psor-alen,Pso)对人类乳腺癌细胞株增殖的影响。方法采用流式细胞术和蛋白印迹法检测槲皮素和补骨脂素对雌激素依赖性乳腺癌细胞MCF-7的影响,并以雌激素受体拮抗剂ICI182,780为工具药来评价槲皮素和补骨脂素发挥雌激素样作用与雌激素受体的关系。结果①槲皮素、补骨脂素在10μmol.L-1可使MCF-7细胞增殖指数明显升高,增加S期细胞的比例,与10-3μmon.L-1E2阳性对照组的变化趋势一致。当ICI182,780分别与E2、金雀异黄素、槲皮素、补骨脂素共孵育48 h后,E2、金雀异黄素、槲皮素、补骨脂素的增殖效应被抑制,细胞周期S期细胞数比例下降,G0/G1期细胞数比例上升。②10μmol.L-1槲皮素和10μmol.L-1补骨脂素均上调MCF-7细胞ERα蛋白水平,而对ERβ蛋白表达没有影响;当分别与ICI182,780共孵育MCF-7细胞ERα蛋白表达被拮抗。结论槲皮素和补骨脂素具有雌激素活性,此作用是通过雌激素受体(ER)介导的;产生的类似金雀异黄素促进MCF-7细胞增殖的作用是通过增加ERα表达实现的。     

异补骨脂素的植物雌激素作用及其机制的探讨

目的利用雌激素受体(estrogenic receptor,ER)阳性乳腺癌T47D细胞和ER阴性乳腺癌MDA-MB231细胞观察异补骨脂素(isopsoralen)的雌激素样作用,并探讨其可能的作用靶点和机制。方法以ER拮抗剂ICI182,780为工具药,采用MTT细胞增殖实验观察异补骨脂素对T47D和MDA-MB231细胞增殖的影响;通过流式细胞术检测细胞周期分布的变化。同时,利用实时荧光定量PCR法及流式细胞术检测异补骨脂素对T47D细胞pS2 mRNA及蛋白表达情况的影响。结果1×10-6mol·L-1和1×10-7mol·L-1异补骨脂素能够促进T47D细胞增殖,提高细胞分裂增殖指数,且该作用可被ICI182,780所拮抗;1×10-6mol·L-1和1×10-7mol·L-1异补骨脂素对MDA-MB231细胞增殖无影响。PCR及流式蛋白检测结果显示:1×10-6mol·L-1和1×10-7mol·L-1异补骨脂素可使pS2 mRNA和蛋白表达增加,同时加入ICI182,780可部分拮抗异补骨脂素对pS2表达的诱导和促进作用。结论异补骨脂素具有植物雌激素作用,该效应可通过作用于靶细胞雌激素受体途径实现。     

槲皮素、补骨脂素对人乳腺癌T47D细胞两种受体亚型表达的影响

目的探讨槲皮素和补骨脂素的雌激素作用以及调控雌激素受体亚型表达的作用机制。方法10μmol.L-1槲皮素和10μmol.L-1补骨脂素分别处理T47D细胞48 h,采用RT-PCR和Western blot方法测定对雌激素依赖性乳腺癌细胞T47D雌激素受体亚型ERα和ERβ表达的影响,并以雌激素受体拮抗剂ICI182,780为工具药来评价槲皮素和补骨脂素发挥雌激素样作用与雌激素受体的关系。结果槲皮素、补骨脂素在10μmol.L-1可明显诱导T47D细胞ERαmRNA和蛋白表达,而对ERβ表达没有影响。当与ICI182,780共孵育T47D细胞ERα表达被拮抗。结论槲皮素、补骨脂素产生的促进ER阳性细胞增殖的雌激素样作用是通过增加ERα表达实现的。     

孕激素及雌激素对乳腺癌细胞RANKL及其受体的调节作用

目的 观察孕激素及雌激素对不同乳腺癌细胞系中核因子kB受体活化因子配体(RANKL)及其受体(RANK、OPG)表达的调节作用.方法 取对数生长期的乳腺癌细胞系T47D、MCF-7及MDA-MB-231,分别给予孕激素及雌激素刺激.采用RT-PCR测定各乳腺癌细胞系中RANKL、RANK、OPG以及孕激素受体(PR)的表达.结果 孕激素可以明显提高T47D及MCF-7细胞中RANKL的表达.孕激素和雌激素作用后,RANK在乳腺癌细胞系T47D及MCF-7中的表达明显下降.然而孕激素及雌激素对于OPG在T47D及MCF-7细胞中表达的调节作用却不明显.结论 RANKL及其受体在T47D与MCF-7细胞系中的表达受到孕激素及雌激素的调节,提示孕激素和雌激素有可能通过RANKL及其受体影响乳腺癌细胞的骨转移.     

应用改良的E—screen实验评估天然物质的类雌激素活性

目的:改良E-screen实验,提高其筛选具有雌激素样作用物质的准确性.方法:构建雌激素受体反义RNA表达质粒pCASER,以脂质体转染MCF-7细胞,G418筛选阳性克隆.PCR检测雌激素受体的DNA是否整和地MCF-7细胞的基因组DNA中,Westernblot检测雌激素受体的表达;MTT法检测细胞的增殖.结果:筛选出一株雌激素受体反义RNA表达克隆(MTASER).17β-雌二醇,金雀异黄素,Dro-loxifen,Miyabenol和Kobophenol在一定浓度均可促进MCF-7细胞增殖,且对MCF-7的促增殖作用大于对MTASER的促增殖作用;表皮生长因子对两株细胞的促增殖作用的差别无显著意义.结论:改良的E-screen实验筛选具有雌激素样作用物质的准确性高于通常的E-screen实验.     

玉米赤霉烯酮对MCF-7和T47D细胞凋亡的抑制作用

玉米赤霉烯酮(ZEA)是一种霉菌毒素，在奶制品及霉变谷类食物中含量较高。据报道，ZEA在结构上与内源性雌激素有相似之处，通过与雌激素受体结合而模拟雌激素效应，增加女性体内雌激素负荷，与乳腺癌发病率的升高有关。本实验室前一阶段的研究表明，ZEA可模拟雌激素作用，促进雌激素依赖性乳腺癌细胞MCF-7及T47D细胞增殖，     

丹参酮ⅡA抗乳腺癌细胞增殖作用研究

目的利用雌激素受体(estrogenic receptor,ER)阳性乳腺癌T47D细胞和ER阴性乳腺癌MDA-MB-231细胞观察丹参酮ⅡA(TanshinoneⅡA)对细胞增殖活性的影响及其对雌激素受体亚型的调节功能。方法以ER拮抗剂ICI182,780为工具药,采用MTT细胞增殖实验观察1×10-6mol.L-1和1×10-7mol.L-1丹参酮ⅡA对T47D和MDA-MB-231细胞增殖的影响。利用实时荧光定量PCR法及流式细胞术检测其对T47D细胞ERα和ERβmRNA及蛋白表达情况的影响。结果丹参酮ⅡA能够抑制T47D细胞增殖,且该作用可被ICI182,780部分拮抗;对MDA-MB-231细胞增殖的抑制作用较其对T47D细胞的作用更为明显。丹参酮ⅡA可使T47D细胞ERα和ERβmRNA和蛋白表达明显增加,并使ERα/ERβ比值有所上升。结论丹参酮ⅡA具有抑制乳腺癌细胞增殖的作用,抑制强度与对其ER亚型的调节作用相关。     

刺槐素对乳腺癌T47D细胞增殖的影响

目的研究刺槐素对乳腺癌T47D细胞增殖的影响,探究刺槐素雌激素样作用的主要介导受体。方法磺酰罗丹明B(SRB)法检测细胞增殖,流式细胞术检测细胞周期的变化,q PCR检测雌激素受体-α(ERα)、雌激素受体-β(ERβ)、细胞增殖抗原标记物(Ki67)mRNA表达,Western blot法检测ERα、ERβ蛋白表达。结果刺槐素浓度为0.001~10μmol·L~(-1),能促进T47D细胞增殖,使S和G_2/M期的细胞比例明显增加,增殖指数升高,同时增加Ki67 mRNA的表达,此作用可被雌激素受体拮抗剂ICI 182.780所拮抗。刺槐素及17β-雌二醇(E2)均可上调ERα和ERβ的表达,刺槐素联合ERα受体拮抗剂(MPP)可逆转刺槐素的促增殖作用,使S和G_2/M期的细胞比例明显降低,减少Ki67mRNA的表达;但刺槐素联合ERβ受体拮抗剂(PHTPP)处理虽可抑制细胞增殖效应,使S和G_2/M期的细胞比例降低,减少Ki67 mRNA的表达,但作用不明显。结论刺槐素具有雌激素样作用,在0.001~10μmol·L~(-1)浓度范围内,可通过调节ERα受体表达来促进T47D细胞的增殖。     

New calmodulin antagonists inhibit in vitro growth of human breast cancer cell lines independent of their estrogen receptor status

Calmodulin plays a key role in the regulation of cell proliferation and calmodulin antagonists may offer a new therapeutic approach in the treatment of breast cancer. Three new specific calmodulin antagonists with improved potency were synthesized and screened on human breast cancer cell lines known to be estrogen receptor (ER)-positive or -negative. These calmodulin antagonists significantly inhibited cell growth as measured by the MTT proliferation assay (p<0.001). Their IC50 values were in the low micromolar range against both ER-positive and -negative variants of the MCF-7 cell line. Two other breast cancer cell lines (ER-positive T-47D and ER-negative MDA-MB-231) were also inhibited by these calmodulin antagonists with IC50 values in a similar range. The level of inhibition was independent of any stimulation of cell growth by estradiol. Calmodulin antagonists effectively reduced cell growth of both ER-positive and -negative human breast cancer cell lines in vitro. Calmodulin antagonists represent a novel therapeutic approach requiring further investigation.     

Effect of estrogen receptor (ER) on benzo[a]pyrene-DNA adduct formation in human breast cancer cells

To investigate the role of estrogen and estrogen receptor (ER) during benzo[a]pyrene (BaP) carcinogenesis, BaP-DNA adduct formation, and DNA synthesis were examined in ER-positive, MCF-7, and ER-negative, MDA-MB-231, human breast cancer cell lines. In MCF-7, the ER-positive human breast cancer cell line, treated with BaP, the formation of BaP-DNA adducts and DNA synthesis were inhibited in a concentration-responsive manner, but there was no change in MDA-MB-231, the ER-negative cell line. In the [3H]BaP-DNA binding assay, an increase of BaP-DNA adduct formation was observed with 17beta-estradiol (E2)-induced ERalpha. Treatments of [3H]BaP in conjunction with the E2 induced a 2.1-fold increase in BaP-DNA adduct over BaP alone in the ER-positive MCF-7 cell line. In addition, the antiestrogen tamoxifen (TAM) blocked this effect by 82%, while E2 produced no change in the ER-negative MDA-MB-231 cell line. These observations suggest that the increased formation of BaP-DNA adducts may be mediated through the ERalpha expressed by E2.     

DNA damage caused by bisphenol A and estradiol through estrogenic activity

Evidence exists that raises concern about genotoxic effects induced by estrogen: oxidative stress caused by estrogen-derived oxidants, DNA adducts formed by estrogen metabolites and estrogen-induced chromosomal aberration. Estrogen receptors (ER) participate in some of these genotoxic effects by estrogen. In this study, we showed the effects of bisphenol A (BPA), an endocrine-disrupting chemical eliciting weak estrogenic activity, and of 17beta-estradiol (E2), on DNA damage in ER-positive MCF-7 cells by Comet assay. Higher concentrations of BPA, more than 1000 times of E2, were needed to induce the same levels of effects by E2. Immunofluorescence microscopy showed that gammaH2AX, an early marker of DNA breaks, increased after treatment with E2 or BPA in MCF-7 cells. gammaH2AX foci colocalized with Bloom helicase, which is considered to be responsible for the repair of DNA damage after treatment with E2 or BPA. Interestingly, DNA damage was not as severe in ER-negative MDA-MB-231 cells as in MCF-7 cells. The ER antagonist ICI182780 blocked E2 and BPA genotoxic effects on MCF-7 cells. These results together suggest that BPA causes genotoxicity ER dependently in the same way as E2.     

Proliferation-stimulating effects of icaritin and desmethylicaritin in MCF-7 cells

Icariin, icaritin and desmethylicaritin are constituents of Epimedium with a similar structure to genistein and daidzein. Using the modified MCF-7 cell proliferation assay (E-SCREEN assessment system), these compounds were tested for their estrogen-like activities. Icaritin and desmethylicaritin, but not icariin, strongly stimulated the proliferation of MCF-7/BUS cells. Cell cycle analysis revealed that the proliferation stimulatory effect was associated with a marked increase in the number of MCF-7/BUS cells in S phase and a significant increase in the G2/M population, with effects similar to those of estradiol. These actions were dose dependent (range from 1 nM to 10 microM) and could be significantly inhibited by the specific estrogen receptor antagonist ICI 182,780 [7 alpha-[9(4,4,5,5,5-pentafluoropentyl)sulfinyl]nonyl)-estra-1,3,5(10)-triene-3,17beta-diol)]. The estrogen receptor-regulated progesterone receptor and PS2 mRNA levels were increased by treatment with icaritin or desmethylicaritin within 24 h and the effects were also reversed by ICI 182,780. It was concluded that icaritin and desmethylicaritin are novel phytoestrogens and that the estrogenic effects of icaritin and desmethylicaritin are mediated by the estrogen receptor.