Distinct functional differences of human progesterone receptors A and B on gene expression and growth regulation in two endometrial carcinoma cell lines

To study the functional differences between the two progesterone receptor isoforms (hPRA and hPRB) in human endometrial cancer, two new endometrial carcinoma cell lines were created-one expressing hPRA and one expressing hPRB.A well-differentiated, hPR-negative Ishikawa cell line was stably transfected with either hPRA or hPRB cDNA. Transfected cells were selected, and two cell lines expressing approximately equal amounts of receptor were isolated-one expressing hPRA (PRA-14) and one expressing hPRB (PRB-59).Cell growth experiments revealed a growth-inhibitory response to progestins (MPA and R5020) in the PRB-59 cells but not in the PRA-14 cells. Differences in expression of genes targeted by the two isoforms were studied using a cDNA expression array technique. A different set of genes appeared to be progesterone regulated in the PRA-14 cells than in the PRB-59 cells. None of the genes were regulated by both hPRA and hPRB. Insulin-like growth factor binding protein 3 expression was studied in more detail as an example of a gene regulated in PRB-59 cells but not in PRA-14 cells.We established a new model to study functional differences between the two hPR isoforms in human endometrial carcinoma cells. This model revealed distinctive differences in target gene regulation between the two hPR isoforms. Moreover, antiproliferative actions of progesterone on human endometrial cancer cells could be observed only in the PRB-expressing cell line.     

Steroid-modulated proliferation of human endometrial carcinoma cell lines: any role for insulin-like growth factor signaling?

OBJECTIVES: Estrogen-stimulated proliferation of the normal and malignant human endometrium is balanced by the differentiating properties of progesterone. This study evaluated the role of insulin-like growth factor (IGF) signaling in steroid-induced modulation of endometrial cancer cell proliferation. METHODS: We used the human endometrial, estrogen-responsive ECC-1 and progesterone-responsive PRAB-36 cell lines. Proliferation studies with IGFs in combination with either estrogen or progesterone were conducted. Furthermore, the mRNA and protein expression of insulin-like growth factor-binding proteins (IGFBPs) was evaluated. RESULTS: Using the ECC-1 cell line, we observed that estrogen-induced proliferation is modulated via the IGF-receptor signaling pathway, and that IGF-1-induced stimulation of proliferation does not influence estrogen receptor signaling. Furthermore, expression of the main modulators of IGF action, the IGFBPs, was found to be regulated by estrogen and progesterone in both cell lines. IGFBP-4 was up-regulated by estrogen in the ECC-1 cell line, and IGFBP-3 and IGFBP-6 were down-regulated by progesterone in the PRAB-36 cell line. CONCLUSION: Estrogen-induced stimulation of proliferation of ECC-1 endometrial cancer cells is partly achieved via IGF signaling. Furthermore, the IGFBPs are regulated by estrogens as well as progestagens and could potentially play a role in the modulation of endometrial cancer cell proliferation.     

乙二醛酶Ⅰ在子宫内膜癌组织和细胞中的表达及其对细胞增殖和凋亡的影响

目的 了解乙二醛酶Ⅰ(GLO-Ⅰ)在子宫内膜癌组织和细胞中的表达情况,探讨GLO-Ⅰ对子宫内膜癌细胞增殖与凋亡的影响.　方法应用免疫组化抗生物素蛋白-生物素复合物(ABC)法检测子宫内膜癌(29份)、正常子宫内膜(19份)组织中GLO-Ⅰ蛋白的表达,紫外分光光度计检测子宫内膜癌及其癌旁组织、正常子宫内膜组织中GLO-Ⅰ的活性.GLO-Ⅰ小分子RNA(siRNA)转染子宫内膜癌细胞株lshikawa细胞后,采用蛋白印迹法及逆转录(RT)-PCR技术分别检测其GLO-Ⅰ蛋白及mRNA的表达水平,采用四甲基偶氮唑蓝(MTT)比色法、流式细胞仪分别检测其细胞增殖及凋亡情况.结果 (1)子宫内膜癌组织中GLO-Ⅰ蛋白的阳性表达率为76%(22/29),正常子宫内膜组织为0/19,两者比较,差异有统计学意义(P<0.01).正常子宫内膜、子宫内膜癌癌旁组织中GLO-Ⅰ活性(分别为1.1、0.8 IU/mg)较弱,子宫内膜癌组织中GLO-Ⅰ活性(92.3 IU/mg)明显升高,差异有统计学意义(P<0.01).(2)Ishikawa细胞转染GLO-Ⅰ silRNA后,其GLO-Ⅰ mRNA的表达水平为0.25±0.06,低于阴性对照(转染与目的基因无关的siRNA)的0.93±0.10,差异有统计学意义(P<0.01);其GLO-Ⅰ蛋白的表达水平为0.38±±0.06,低于阴性对照的0.94±0.13,差异也有统计学意义(P<0.01).(3)Ishikawa细胞转染GLO-Ⅰ siRNA后,其细胞增殖能力与空白对照(仅加转染试剂)比较明显降低(P=0.028);其细胞凋亡率为(6.7±0.8)%,高于阴性对照的(1.2±0.4)%和空白对照的(1.4±0.4)%,差异有统计学意义(P<0.01).结论 GLO-Ⅰ在子宫内膜癌组织和细胞中均呈过度表达,子宫内膜癌组织中GLO-Ⅰ活性异常升高.抑制GLO-Ⅰ基因表达可促进子宫内膜癌细胞凋亡,并抑制其增殖.     

子宫内膜癌中孕激素受体亚型表达及其甲基化状态的研究

目的:研究子宫内膜癌中孕激素受体亚型PRA、PRB表达与其启动子区甲基化状态的关系,探讨子宫内膜癌中孕激素受体亚型表达下调的机制。方法:(1)应用Real-Time PCR法检测子宫内膜癌及正常组织中孕激素受体亚型PRA、PRB mRNA的表达及去甲基化试剂5-Aza-CdR处理Ishikawa细胞前后孕激素两种受体亚型及DNA甲基化转移酶mRNA的表达;(2)应用甲基化特异性PCR(MS-PCR)检测子宫内膜癌细胞系Ishikawa中PRA、PRB的甲基化状态。结果:与正常子宫内膜组织比较,子宫内膜癌组织中,总PR表达显著降低,与病理类型相关;PRB表达显著下降,与其临床特征无关。子宫内膜癌细胞系Ishikawa中,加入5-Aza-CdR2.5μmol/L48h后,孕激素受体亚型PRA、PRB甲基化条带均消失;孕激素受体亚型PRA、PRB mRNA表达水平增加;同时Ishikawa细胞中DNA甲基转移酶DNMT1、DNMT3B表达下调。结论:子宫内膜癌组织中,孕激素受体亚型mRNA表达下调可能与子宫内膜癌的发生相关;孕激素受体亚型表达下调与其启动子区甲基化状态相关;去甲基化试剂5-Aza-CdR可逆转基因启动子区的甲基化状态,恢复PR基因的表达。     

雌、孕激素对人子宫内膜Pbx2蛋白表达的影响

目的:探讨人子宫内膜腺上皮细胞和基质细胞中雌、孕激素对Pbx2蛋白表达的影响。方法:采用免疫组织化学链霉菌抗生物素蛋白-过氧化物酶(SP)连接法检测人增生期、分泌中期和蜕膜期子宫内膜中Pbx2的表达和分布;体外培养人子宫内膜基质细胞和高分化子宫内膜癌细胞Ishikawa,分别加入雌激素、孕激素、雌、孕激素联合刺激48 h,并以不加雌、孕激素的基质细胞核和Ishikawa细胞为对照组,采用免疫组织化学、免疫印迹法测定各种条件下Ishikawa细胞中Pbx2蛋白的表达。结果:①在人各期子宫内膜组织中,Pbx2表达于腺上皮细胞和基质细胞的细胞核中;Pbx2在分泌中期和蜕膜期基质细胞中的表达显著高于增生期,但在腺上皮细胞中增生期组织的表达高于分泌中期和蜕膜期,差异均具有统计学意义(P<0.05)。②Western blotting结果显示,在孕激素和雌、孕激素联合处理Ishikawa细胞组中,Pbx2的表达显著低于对照组(P<0.05),雌激素处理后Pbx2的表达与其他各组间的表达无显著性差异(P>0.05),在人子宫内膜基质细胞(ESC)中,Pbx2的表达在雌、孕激素处理各组间比较均无统计学差异(P>0.05)。结论:在人子宫内膜腺上皮Ishikawa细胞中孕激素对Pbx2的表达具有下调作用,在人子宫内膜基质细胞中,Pbx2的调控可能是非雌、孕激素依赖性的。     

Hormonal regulation of galectin 3 in trophoblasts and its effects on endometrium

Previous studies had shown important functions of galectin 3 (Gal-3) in endometrium during embryo implantation, in regulation of endometrial cell proliferation and adhesion by interacting with integrin β3. In this study, we investigated hormonal regulation of Gal-3 in trophoblasts and its extracellular effects on endometrium. We used BeWo and RL95-2 cells as a model of trophoblastic and endometrial epithelial cells, respectively, to create an in vivo model of embryo implantation. Our results indicated that 17β-estradiol (E2), progesterone (P4), and human chorionic gonadotropin (hCG) induced the expression of Gal-3 and promoted its secretion from BeWo cells. The exogenous Gal-3 inhibited cell proliferation and induced apoptosis of endometrial cells (RL95-2 cells) through activation of integrin β1. We further validated the proapoptotic effect of Gal-3 secreted by trophoblastic cell on endometrial cells by culturing RL95-2 cells with Bewo cells and measuring the apoptotic rate. Our analysis provides new insight into the critical roles of Gal-3 in embryo implantation.     

Epidermal growth factor receptor signaling enhanced by long-term medroxyprogesterone acetate treatment in endometrial carcinoma

OBJECTIVE: Progestin is an effective endocrine treatment for patients with atypical hyperplasia or with endometrial carcinoma that is estrogen receptor (ER) positive and progesterone receptor (PR) positive. However, long-term progestin treatment may lead to resistance. We have studied the progestin resistance phenotype that frequently develops in endometrial carcinoma. METHODS: Ishikawa endometrial carcinoma cells were cultured for a long period (10 months) in the presence of the synthetic progestin medroxyprogesterone acetate (MPA), thereby generating a subline refractory to the growth-suppressive effects of MPA. RESULTS: The MPA-resistant subline showed growth stimulation rather than inhibition after MPA treatment. Immunocytochemical analysis showed reduced ER alpha and PR-B expression and increased ER beta expression in this subline compared with parental Ishikawa cells. Progestin-resistant Ishikawa cells also showed increased expression of transforming growth factor alpha (TGFalpha), the epidermal growth factor receptor (EGFR), and EGFR tyrosine kinase (EGFR-TK); MPA treatment further stimulated the expression of TGFalpha in these cells. Additionally, progestin-resistant Ishikawa cells were highly sensitive to growth stimulation by TGFalpha and to growth inhibition by the EGFR-TK-specific inhibitor AG1478, and they showed increased dependence on TGFalpha-EGFR signaling. CONCLUSIONS: Our results suggest that prolonged treatment of endometrial carcinoma cells with MPA induces resistance to the growth-suppressive effects of MPA and enhances cancer cell proliferation. The downregulation of ER alpha and PR-B, the upregulation of ER beta, and highly activated TGF-EGFR signaling are thus likely to contribute to progestin resistance in endometrial carcinoma. Therefore, an EGFR-TK-specific inhibitor might be useful in the treatment of progestin-resistant endometrial carcinoma.     

Up-regulation of DNA methyltransferase 3B expression in endometrial cancers

OBJECTIVE: To understand the role of epigenetic regulation in the pathogenesis of endometrial cancer, we have characterized DNA methyltransferase 3B (DNMT3B) gene expression in normal, Grade I and Grade III endometrioid cancers, and examined DNMT3B promoter activities in endometrial cancer cell lines. METHODS: DNMT3B expression was measured in normal, Grade I, and Grade III endometrioid cancer samples. Real-time PCR and Western blot analysis were performed to compare DNMT3B mRNA and protein levels. DNMT3B levels were also compared among endometrial cell lines including those for Ishikawa, KLE, AN3, RL-95, HEC-1A, and HEC-1B. DNMT3B promoter reporter plasmids were constructed. Promoter activities in well and poorly differentiated cell lines were compared by in vitro reporter gene transfection. RESULTS: DNMT3B was significantly up-regulated in both Grade I and Grade III cancers as compared to normal controls. Western blot analysis confirmed the increased DNMT3B protein expression in cancer tissues. It was also found that the well-differentiated endometrial cell line, Ishikawa, expressed lower levels of DNMT3B than the poorly differentiated KLE cells, the expression patterns similar to those observed in tumor specimens. CONCLUSION: The results suggest that DNMT3B overexpression may play a significant role in endometrial cancer development. In addition, the transfection experiments indicated that DNMT3B promoters are more active in the poorly differentiated endometrial cancer cell lines, suggesting that the in vitro assay provides a useful model for studying the DNMT3B transactivation mechanism related to tumor transformation.     

ING4在正常子宫内膜及子宫内膜癌的表达及临床意义

目的:研究生长抑制因子4(ING4)在正常子宫内膜及子宫内膜癌组织中的表达,探讨ING4在子宫内膜癌发生、发展中的作用,为子宫内膜癌的临床预防及治疗提供新的标志物。方法:利用荧光定量PCR、半定量RT-PCR、Western-blot及免疫组化等方法分别检测正常子宫内膜细胞及子宫内膜癌细胞系Ishikawa、HHUA及子宫内膜癌组织中ING4基因的表达,并进行分析比较。结果:子宫内膜癌细胞中ING4基因的表达量显著低于正常子宫内膜细胞(P<0.05),且ING4在Ishikawa和HHUA这两种子宫内膜癌细胞系之间的表达量没有显著性差异(P>0.05)。Western-blot结果显示,正常子宫内膜细胞的ING4蛋白表达量显著高于Ishikawa和HHUA这两种细胞系(P<0.05),HHUA细胞系的ING4蛋白表达量显著高于Ishikawa细胞系(P<0.05)。免疫组化结果显示,ING4在不同组织内的表达量差异有统计学意义(P<0.05),正常子宫内膜细胞内的表达量最高,其次是复杂性及不典型增生子宫内膜,子宫内膜癌内的ING4表达量最低。结论:ING4基因表达的下调与子宫内膜癌发生、发展可能有一定关系,对子宫内膜癌的诊断有一定的参考意义。     

BAG-1 expression in normal and neoplastic endometrium

OBJECTIVE: BAG-1 has anti-apoptotic actions and is known to bind BCL-2 and steroid receptors. High levels of BAG-1 have been implicated as a prognostic indicator in breast cancer. Whether this observation can be generalized to endometrial cancer remains unknown. METHODS: IRB permission was obtained for use of human discarded tissue. Immunohistochemical analyses were performed on: proliferative endometrium (PEM, 6), secretory endometrium (SEM, 28), "low-grade" neoplastic lesions (complex atypical hyperplasia and grade 1 endometrial adenocarcinomas) (19), and "high-grade" cancers (grade 2 and 3 endometrial adenocarcinomas) (13). The level of total BAG-1 and its isoforms was evaluated by Western blot in lysates from Ishikawa cells (grade 1), MFE 296 cells (grade 2), and SK-UT(2) cells (grade 3). RESULTS: The proportion of "high-grade" cancers with positive cytoplasmic staining for BAG-1 was higher than that of secretory endometrium (P = 0.006). Additionally, the proportion of specimens with positive staining for nuclear BAG-1 expression was significantly higher among high-grade carcinoma specimens compared to secretory specimens (P = 0.009). A high proportion (91%) of all specimens were positive for BCL-2, limiting the ability to subcategorize the other variables analyzed. There was no relationship between positive nuclear BAG-1 expression and either estrogen receptor (ER) or progesterone receptor (PR) expression. BAG-1 was expressed in the three cell lines evaluated and total BAG-1 level was not different among the different cell lines. CONCLUSION: BAG-1 is expressed in the endometrium. High-grade cancers stain more frequently than secretory endometrium for both cytoplasmic and nuclear BAG-1 expression, perhaps indicating an association between expression of BAG-1 and prognosis.     

Black cohosh inhibits 17β-estradiol-induced cell proliferation of endometrial adenocarcinoma cells

This study was conducted to investigate the effect of black cohosh (BC) extract on the proliferation and apoptosis of Ishikawa cells. Ishikawa human endometrial adenocarcinoma cells were treated with or without BC (1, 5, 10 and 25?μM) and cell proliferation and cytotoxicity were measured by CCK-8 assays and flow cytometry analysis. Additionally, Ishikawa cells were treated with 17β-estradiol (E2), E2?+?progesterone and E2?+?BC (5 and 10?μM) and the effect of BC and progesterone on E2-induced cell proliferation was analyzed. BC decreased the proliferation of Ishikawa cells at a dose-dependent rate compared with the control group (p?p?相似文献   

雌激素受体相关受体α过度表达对雌激素受体阴性的子宫内膜癌细胞增殖的影响

目的探讨雌激素受体相关受体α（ERRα）在雌激素受体（ER）阴性及阳性的子宫内膜癌细胞中的作用。方法 将真核表达质粒pSG—ERRα（0．5、1．0、1．5、2．5μg）瞬时转染子宫内膜癌细胞株HEC-1A（ER阴性）、HEC-1B（ER阴性）、Ishikawa（ER阳性）,采用定量RT-PCR技术和蛋白印迹法（westernblot）检测ERRα mRNA和蛋白的表达情况;采用流式细胞仪分析细胞周期,并计数细胞的增殖情况。结果 转染pSG—ERRα质粒后,HEC-1A、HEC-1B、Ishikawa细胞在mRNA和蛋白水平均能检测到ERRet的表达增加。HEC-1B、HEC-1A、Ishikawa细胞未转染时ERRα mRNA的表达水平分别为2104．2、2870．6、1476．8copies／ng,转染后3者ERRα mRNA的表达水平分别为9835．3、9644．4、8008．6copies／ng,分别与各自未转染的细胞比较,差异均有统计学意义（P值分别为0．004、0．002、0．002）。HEC-1A、HEC-1B、Ishikawa细胞未转染时ERRα蛋白的表达水平分别为0．823、0．192、0．673,转染后3者ERRα蛋白的表达水平分别为1．128、1．104、1．008,分别与各自未转染的细胞比较,差异均有统计学意义（P〈0．05）。随着转染pSG—ERRα质粒质量的增加,HEC-1A、HEC-1B细胞的S期和G2／M期细胞比例明显上升（P〈0．01）。HEC-1B、HEC-1A细胞转染0．5、1．0μg pSG-ERRα质粒后,细胞在转染后24—96h间生长速度显著加快（P〈0．05）。结论ERRα过度表达是ER阴性的子宫内膜癌细胞株HEC-1A、HEC-1B的一种细胞增殖机制。     

Molecular tools to reestablish progestin control of endometrial cancer cell proliferation

OBJECTIVE: Endometrial cancers often arise in a setting of estrogen stimulation unopposed by the differentiating effects of progesterone. Our laboratory and others have previously shown that progesterone receptor down-regulation or perturbation of progesterone receptor isoform A or B expression is associated with the development of poorly differentiated endometrial cancers that are not growth inhibited by progestins. The purpose of these studies was to reestablish high progesterone receptor isoform A and B gene expressions in such endometrial cancer cells and to examine the effects of progestin treatment on cell growth and metastatic potential after this transformation. STUDY DESIGN: To induce high levels of expression of the progesterone receptor isoforms in KLE and Hec50 endometrial cancer cells, adenoviral vectors encoding the genes for progesterone receptor isoforms A and B were created. The characteristic ability of cancer cells to grow independently of anchorage to the surrounding solid matrix was measured by counting colony formation on soft agar for 8 to 14 days. Cell proliferation in response to a time course of progestin treatment was tested with flow cytometry. RESULTS: After treatment with a control vector without a progesterone receptor--encoding insert, no effect of progestin treatment on cell proliferation was found; after treatment with vectors encoding progesterone receptor isoform A or B, however, progestin treatment resulted in significant inhibition of cell growth. The anchorage-independent cell growth on soft agar assay showed that by 8 to 14 days the number of cell colonies was reduced by 50% relative to control preparations in the presence of progesterone receptor isoform A plus progestin (P <.0001, both Hec50 and KLE cell lines) and by 90% in the presence of progesterone receptor isoform B plus progestin (P <.0001, both Hec50 and KLE cell lines). Progestin treatment also resulted in a time-dependent reduction in cell proliferation as measured by flow cytometry. Although transfection with both progesterone receptor isoforms A and B reduced cell proliferation according to our assays, progesterone receptor isoform B caused a much more dramatic decrease in cell growth (P =.001, Hec50 cells; P <.0001, KLE cells). CONCLUSION: In poorly differentiated endometrial cancer cells that are resistant to progestin therapy, adenovirus-induced expressions of progesterone receptors A and B reestablish progestin control of endometrial cancer cell proliferation.     

HOXA10在子宫内膜癌中的表达及调控机制探讨

目的:探讨HOXA10在子宫内膜癌组织中的表达情况,以及miRNA135a对HOXA10表达的调控和对子宫内膜癌细胞侵袭能力的影响。方法:通过靶基因预测确定miRNA135a与HOXA10的相关性。应用免疫组化法检测HOXA10在子宫内膜癌组织中的表达。通过脂质体转染法瞬时转染HEC-1B和Ishikawa细胞系建立瞬时过表达miRNA135a模型。Real-time PCR和Western blot法检测转染前后HOXA10 mRNA和蛋白水平表达的变化,通过划痕实验、Transwell侵袭实验观察细胞侵袭和迁移能力的变化。结果:子宫内膜癌中HOXA10表达水平显著低于正常子宫内膜组织(P0.01);过表达miRNA135a后,HEC-1B和Ishikawa细胞的迁移和侵袭能力显著增强,差异有统计学意义(P0.01),两种细胞中HOXA10 mRNA和蛋白水平均显著降低(P0.01)。结论:子宫内膜癌中miRNA135a通过抑制HOXA10促进内膜癌细胞的侵袭和迁移能力,参与子宫内膜癌生物学行为的调控。