叉头盒蛋白 A1（FOXA1）在乳腺癌中的表达及其临床意义

目的：研究叉头盒蛋白A1（ FOXA1）在良性乳腺肿瘤、乳腺癌及癌旁组织中的表达,以及与临床资料的相关性。方法采用免疫组织化学方法,检测54例乳腺癌、54例癌旁组织及20例良性乳腺肿瘤（10例纤维腺瘤和10例导管内乳头状瘤）中FOXA1的表达。分析FOXA1的表达与患者年龄、癌组织雌激素受体（ ER）、孕激素受体（ PR）、细胞增殖核抗原KI67、人类表皮生长因子受体2（HER2）、肿瘤分期、瘤体大小以及阳性淋巴结数等临床资料的关系。结果 FOXA1在乳腺癌组织中的阳性率为68．5％（37／54）,癌旁组织中的阳性率为88．9％（48／54）,良性乳腺肿瘤中的阳性率为100％（20／20）,FOXA1在乳腺癌与癌旁组织间、乳腺癌与良性乳腺肿瘤间的表达差异有统计学意义（P＜0．05）,而在癌旁组织与良性乳腺肿瘤间的表达差异无统计学意义（ P＞0．05）;FOXA1的表达与组织学分级、Ki67呈负相关,与ER、PR呈正相关;FOXA1表达在各近似分子亚型间、Luminal A亚型与非Luminal A亚型间、Luminal亚型与非Luminal亚型之间有差异性。结论乳腺癌组织中普遍表达FOXA1,Luminal A型中最高,提示FOXA1可能成为乳腺癌患者预后良好的标志物之一。     

Cryptotanshinone switches target from estrogen receptor α to breast cancer resistance protein(BCRP/ABCG2) to reverse multidrug resistance in breast cancer

OBJECTIVE Targeting individual molecule is not only difficult to cure multigenic cancers, but also prone to inducing resistance. The so-cal ed multidrug resistance(MDR) in breast cancer is highly associated with estrogen receptor α induction and the overexpression of breast cancer resistance protein(BCRP) transporter.Thus, one of the strategies to overcome MDR is to inhibit the expression of the transporter by small molecule inhibitors. METHODS Western blotting and RT-PCR were used respectively for quantification of protein expression and m RNA, non-reducing gradientgel electrophoresis and fluorescence resonance energy transfer(FRET) microscopy imaging for determination of BCRP dimer. RESULTS Cryptotanshinone(CPT) a natural anti-cancer compound,was found to bind BCRP and inhibit its membrane dimerization to attenuate its transport function. And this process is dependent on estrogen receptor α(ERα) in breast cancer. Furthermore, the resistant breast cancer cells with high BCRP expression are also sensitive to CPT followed with the inhibition of membrane dimer of BCRP although they are ERα-negative, suggesting that BCRP expression is essential to CPT reversing the resistance.Meanwhile, the combination of CPT and chemotherapy drugs could obviously enhance the chemotherapeutic effect in vitro. CONCLUSION Totally, we thought that CPT is a novel natural BCRP inhibitor via blocking the formation of BCRP membrane dimer. At the presence of ERα, it functions via ERα regulation, but directly propels BCRP at the absence of ER in resistant cells. CPT can target multi molecules and switch the target from ERα to BCRP in ERα-negative breast cancer, contributing to decrease the occurrence of resistance and reverse multidrug resistance in breast cancer.     

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。     

Hexachlorobenzene induces cell proliferation and IGF-I signaling pathway in an estrogen receptor α-dependent manner in MCF-7 breast cancer cell line

Hexachlorobenzene (HCB) is an organochlorine pesticide widely distributed in the biosphere. ERα regulates the expression of genes involved in growth and development, and plays an important role in breast cancer. The present study focuses attention on the effect of HCB (0.005, 0.05, 0.5, 5 μM) on cell proliferation in estrogen receptor α (ERα)(+) MCF-7, and ERα(−) MDA-MB-231 breast cancer cell lines. We also studied the insulin growth factor-I (IGF-I) signaling pathway in MCF-7 cells. HCB (0.005 and 0.05 μM) stimulated cell proliferation in MCF-7, but not in MDA-MB-231 cells. The pesticide increased apoptosis in MCF-7, at HCB (0.5 and 5 μM). At these doses, HCB induced the expression of the aryl hydrocarbon receptor (AhR)-regulated gene cytochrome P4501A1. MCF-7 cells exposed to HCB (0.005 and 0.05 μM) overexpressed IGF-IR and insulin receptor (IR). IRS-1-phosphotyrosine content was increased in a dose dependent manner. ICI 182,780 prevented HCB-induced cell proliferation and IGF-I signaling in MCF-7 cells incubated in phenol-red free media. In addition, HCB (0.005 μM) increased c-Src activation, Tyr537-ERα phosphorylation and ERα down-regulation. Taken together, our data indicate that HCB stimulation of cell proliferation and IGF-I signaling is ERα dependent in MCF-7 cells.     

4-氨基-2-三氟甲基苯基维甲酸酯对MCF-7细胞增殖和分化的影响及其机制研究

目的研究4-氨基-2-三氟甲基苯基维甲酸酯(4-ami-no-2-trifluoromethyl-phenyl retinate,ATPR)对人乳腺癌MCF-7细胞增殖和分化的作用及其可能机制。方法不同浓度的ATPR作用MCF-7细胞后,绘制细胞生长曲线,分析细胞增殖情况;瑞氏-吉姆萨染色法观察细胞形态学改变;酶联免疫法(ELISA法)检测粘蛋白(mucin 1,MUC-1)活性;RT-PCR法检测维甲酸受体(RARα、RARβ、RARγ)、维甲酸受体诱导基因1(RRIG1)、雌激素受体(ERα、ERβ)mRNA的表达;Western blot法检测RARα、RARβ、RARγ蛋白的表达。结果 ATPR明显抑制MCF-7细胞增殖,且随浓度和时间增加而逐渐增强;镜下观察ATPR作用72 h后MCF-7细胞形态趋向正常细胞分化;ELISA结果显示ATPR明显降低MCF-7细胞培养上清MUC-1浓度(P<0.05);ATPR作用MCF-7细胞72 h后,RARβ、RRIG1、ERβ表达增强(P<0.05),RARγ表达下调(P<0.05),RARα和ERα表达则无明显变化。结论 ATPR可明显抑制MCF-7细胞增殖并诱导其分化程度增高,其机制可能与调节维甲酸受体和雌激素受体平衡,并上调RRIG1表达有关。     

Her-2、TopoⅡα和激素受体在乳腺癌中的表达及意义

目的探讨Her-2、TopoⅡα、ER和PR在乳腺癌中的表达及临床意义。方法免疫组织化学检测80例乳腺癌组织中Her-2、TopoⅡα、ER和PR的表达情况,并进行统计学分析。结果80例乳腺癌ER、PR、Her-2及TopoⅡα表达阳性率分别为72.5%、62.5%、30%和86.3%;Her-2及TopoⅡα随着临床分期增加和腋窝淋巴结转移数目的增加,其阳性表达率亦增加,且有显著性差异(P<0.05)。ER、PR阳性表达率则相反,无显著性差异(P>0.05)。ER、PR阳性表达率与Her-2及TopoⅡα阳性表达呈负相关(P>0.05)。结论联合检测Her-2、TopoⅡα、ER和PR,对于乳腺癌的治疗具有指导意义,也是判断预后的重要指标。     

The selective estrogen receptor modulator bazedoxifene inhibits hormone-independent breast cancer cell growth and down-regulates estrogen receptor α and cyclin D1

Bazedoxifene (BZA) is a third-generation selective estrogen receptor modulator (SERM) that has been approved for the prevention and treatment of postmenopausal osteoporosis. It has antitumor activity; however, its mechanism of action remains unclear. In the present study, we characterized the effects of BZA and several other SERMs on the proliferation of hormone-dependent MCF-7 and T47D breast cancer cells and hormone-independent MCF-7:5C and MCF-7:2A cells and examined its mechanism of action in these cells. We found that all of the SERMs inhibited the growth of MCF-7, T47D, and MCF-7:2A cells; however, only BZA and fulvestrant (FUL) inhibited the growth of hormone-independent MCF-7:5C cells. Cell cycle analysis revealed that BZA and FUL induced G(1) blockade in MCF-7:5C cells; however, BZA down-regulated cyclin D1, which was constitutively overexpressed in these cells, whereas FUL suppressed cyclin A. Further analysis revealed that small interfering RNA knockdown of cyclin D1 reduced the basal growth of MCF-7:5C cells, and it blocked the ability of BZA to induce G(1) arrest in these cells. BZA also down-regulated estrogen receptor-α (ERα) protein by increasing its degradation and suppressing cyclin D1 promoter activity in MCF-7:5C cells. Finally, molecular modeling studies demonstrated that BZA bound to ERα in an orientation similar to raloxifene; however, a number of residues adopted different conformations in the induced-fit docking poses compared with the experimental structure of ERα-raloxifene. Together, these findings indicate that BZA is distinct from other SERMs in its ability to inhibit hormone-independent breast cancer cell growth and to regulate ERα and cyclin D1 expression in resistant cells.     

ERα signaling imparts chemotherapeutic selectivity to selenium nanoparticles in breast cancer

The present study focuses on the synthesis of stable selenium nanoparticles (SeNPs) and the elucidation of their mechanism of action in preventing the growth of mammary tumors. Selenious acid and reduced glutathione in the presence of sodium alginate were used as precursors for synthesis of SeNPs. Cell viability and expression of apoptotic markers (pp38, Bax, and cytochrome c) were assessed in MCF-7 and MDA-MB-231 breast cancer cells treated with SeNPs. Reduction in tumor volume was measured in rats with dimethylbenz[a]anthracene-induced mammary tumors. Synthesized SeNPs ranged in size from 40 to 90 nm and were stable up to 3 months of storage. We report that SeNP-induced cell death and expression of pp38, Bax, and cytochrome c were significantly higher in estrogen receptor-α (ERα)-positive cells (MCF-7) but not in ERα-negative cells (MDA-MB-231). Interestingly, animals showing significant decrease in tumor volume (small tumors) had lower levels of ERα as compared with animals showing a nonsignificant decrease in tumor volume (large tumor). This is the first report in our knowledge suggesting that the anticancer activity of SeNPs correlates with the level of ERα in breast cancer cells both in vivo and in vitro. FROM THE CLINICAL EDITOR: This study focuses on the synthesis of selenium nanoparticles (SeNPs) with the goal of preventing the growth of breast cancer cells, suggesting that the anticancer activity of SeNPs correlates with the level of ERα in breast cancer cells both in vivo and in vitro.     

Selectively targeting estrogen receptors for cancer treatment

Estrogens regulate growth and development through the action of two distinct estrogen receptors (ERs), ERα and ERβ, which mediate proliferation and differentiation of cells. For decades, ERα mediated estrogen signaling has been therapeutically targeted to treat breast cancer, most notably with the selective estrogen receptor modulator (SERM) tamoxifen. Selectively targeting ERs occurs at two levels: tissue selectivity and receptor subtype selectivity. SERMs have been developed with emphasis on tissue selectivity to target ER signaling for breast cancer treatment. Additionally, new approaches to selectively target the action of ERα going beyond ligand-dependent activity are under current investigation. As evidence of the anti-proliferative role of ERβ accumulates, selectively targeting ERβ is an attractive approach for designing new cancer therapies with the emphasis shifted to designing ligands with subtype selectivity. This review will present the mechanistic and structural features of ERs that determine tissue and subtype selectivity with an emphasis on current approaches to selectively target ERα and ERβ for cancer treatment.     

Different mechanisms of action of 2, 2’, 4, 4’‐tetrabromodiphenyl ether (BDE‐47) and its metabolites (5‐OH‐BDE‐47 and 6‐OH‐BDE‐47) on cell proliferation in OVCAR‐3 ovarian cancer cells and MCF‐7 breast cancer cells

Data concerning the possible action of polybrominated diphenyl ethers (PBDEs) in hormone‐dependent cancer are scarce. Some data showed that PBDEs may directly affect breast cancer cells formation and only one research showed increased proliferation of the OVCAR‐3 cells, but the results are ambiguous and the mechanisms are not clear. There is growing evidence that not only parent compounds but also its metabolites may be involved in cancer development. The present study was, therefore, designed to determine the effect of BDE‐47 and its metabolites (2.5 to 50 ng ml^–1) on proliferation (BrdU), cell‐cycle genes (real‐time PCR) and protein expression (Western blot), protein expression of oestrogen receptors (α β), extracellular signal‐regulated kinases 1 and 2 (ERK1/2) and protein kinase Cα (PKCα) in OVCAR‐3 ovarian and MCF‐7 breast cancer cells. In OVCAR‐3 cells, the parent compound stimulated cell proliferation by activating CDK1, CDK7, E2F1 and E2F2. Independent of time of exposure, BDE‐47 had no effect on ERα and ERβ protein expression and ERK1/2 and PKCα phosphorylation. Metabolites had no effect on cell proliferation but increased both ERs protein expression and ERK1/2 and PKCα phosphorylation. In MCF‐7 cells, the parent compound displayed no effect on cell proliferation but decreased ERα and increased ERβ protein expression with concomitant induction of PKCα phosphorylation. Both metabolites increased MCF‐7 cell proliferation, ERK1/2 and PKCα phosphorylation and decreased ERα and ERβ protein expression.We suggest that studies concerning PBDEs with fewer bromine atoms should be continued to understand environmental links to different hormone‐dependent cancers. Copyright © 2016 John Wiley & Sons, Ltd.