Sustained Activation of Extracellular Signal‐Regulated Kinase (ERK) Signaling in Human Prostate Cancer LNCaP Cells Depleted of Androgen

L. Drew, R. Fine, A. Raffo, D. Petrylak
{"title":"Sustained Activation of Extracellular Signal‐Regulated Kinase (ERK) Signaling in Human Prostate Cancer LNCaP Cells Depleted of Androgen","authors":"L. Drew, R. Fine, A. Raffo, D. Petrylak","doi":"10.1046/J.1525-1411.2001.32003.X","DOIUrl":null,"url":null,"abstract":"Objectives: The mitogen-activated protein kinase (MAPK) cascade is involved in the control of cell growth and differentiation. In this study, we have investigated the effect of androgen withdrawal on this pathway and its potential role in the induction of neuroendocrine (NE) differentiation. For this purpose, we used the androgen-sensitive human prostate cancer LNCaP cells as an in vitro model. \n \n \n \nMethods and Results: The incubation of LNCaP cells for 6 days in medium, either free of serum or supplemented with serum depleted of steroids (i.e., charcoal-stripped serum), resulted in NE differentiation as determined by growth arrest, the formation of neurites, and an increase in neuron-specific enolase protein expression. Sustained extracellular-regulated kinase (ERK) phosphorylation/activity and enhanced ERK/MAPK kinase (MEK) activity also were observed on serum or steroid withdrawal. A synthetic androgen, mibolerone, blocked both NE differentiation and ERK phosphorylation induced by the incubation of the cells in steroid-depleted medium, thus confirming androgen specificity. Furthermore, a culture of LNCaP cells in complete medium supplemented with a 5-α-reductase inhibitor, finasteride, also induced NE differentiation and ERK phosphorylation. This implicates depletion of the principal prostatic androgen, dihydrotestosterone, as the specific mediator of these effects. In contrast to ERK, the phosphorylation status of the stress-activated MAPK members c-Jun N-terminal kinase and p38 was not altered by steroid withdrawal. The MEK inhibitor U0126 was used to study the potential role of ERK in regulating NE differentiation. However, U0126 did not reverse NE differentiation associated with steroid depletion, even though ERK phosphorylation was suppressed. The role of erb B tyrosine kinase receptors in mediating ERK phosphorylation during steroid depletion also was investigated. erb B1 protein levels decreased, erb B3 protein levels and phosphorylation remained unaltered, and erb B2 phosphoprotein levels increased after steroid depletion. Stable expression of an intracellular antibody to erb B2, however, did not prevent the up-regulation of ERK phosphorylation that is associated with steroid depletion. \n \n \n \nConclusions: Androgen depletion induces sustained erb B-independent ERK signaling in LNCaP cells, however, this pathway is not essential for the associated NE differentiation.","PeriodicalId":22947,"journal":{"name":"The open prostate cancer journal","volume":"5 1","pages":"105-117"},"PeriodicalIF":0.0000,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The open prostate cancer journal","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1046/J.1525-1411.2001.32003.X","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 3

Abstract

Objectives: The mitogen-activated protein kinase (MAPK) cascade is involved in the control of cell growth and differentiation. In this study, we have investigated the effect of androgen withdrawal on this pathway and its potential role in the induction of neuroendocrine (NE) differentiation. For this purpose, we used the androgen-sensitive human prostate cancer LNCaP cells as an in vitro model. Methods and Results: The incubation of LNCaP cells for 6 days in medium, either free of serum or supplemented with serum depleted of steroids (i.e., charcoal-stripped serum), resulted in NE differentiation as determined by growth arrest, the formation of neurites, and an increase in neuron-specific enolase protein expression. Sustained extracellular-regulated kinase (ERK) phosphorylation/activity and enhanced ERK/MAPK kinase (MEK) activity also were observed on serum or steroid withdrawal. A synthetic androgen, mibolerone, blocked both NE differentiation and ERK phosphorylation induced by the incubation of the cells in steroid-depleted medium, thus confirming androgen specificity. Furthermore, a culture of LNCaP cells in complete medium supplemented with a 5-α-reductase inhibitor, finasteride, also induced NE differentiation and ERK phosphorylation. This implicates depletion of the principal prostatic androgen, dihydrotestosterone, as the specific mediator of these effects. In contrast to ERK, the phosphorylation status of the stress-activated MAPK members c-Jun N-terminal kinase and p38 was not altered by steroid withdrawal. The MEK inhibitor U0126 was used to study the potential role of ERK in regulating NE differentiation. However, U0126 did not reverse NE differentiation associated with steroid depletion, even though ERK phosphorylation was suppressed. The role of erb B tyrosine kinase receptors in mediating ERK phosphorylation during steroid depletion also was investigated. erb B1 protein levels decreased, erb B3 protein levels and phosphorylation remained unaltered, and erb B2 phosphoprotein levels increased after steroid depletion. Stable expression of an intracellular antibody to erb B2, however, did not prevent the up-regulation of ERK phosphorylation that is associated with steroid depletion. Conclusions: Androgen depletion induces sustained erb B-independent ERK signaling in LNCaP cells, however, this pathway is not essential for the associated NE differentiation.
查看原文
分享 分享
微信好友 朋友圈 QQ好友 复制链接
本刊更多论文
细胞外信号调节激酶(ERK)信号在雄激素缺失的人前列腺癌LNCaP细胞中的持续激活
目的:丝裂原活化蛋白激酶(MAPK)级联参与细胞生长和分化的调控。在这项研究中,我们研究了雄激素戒断对这一途径的影响及其在诱导神经内分泌(NE)分化中的潜在作用。为此,我们使用雄激素敏感的人前列腺癌LNCaP细胞作为体外模型。方法和结果:LNCaP细胞在培养基中孵育6天,不含血清或添加去类固醇血清(即木炭剥离血清),通过生长停滞、神经突形成和神经元特异性烯醇化酶蛋白表达的增加,导致NE分化。持续的细胞外调节激酶(ERK)磷酸化/活性和增强的ERK/MAPK激酶(MEK)活性也在血清或类固醇戒断中观察到。合成雄激素米bolerone阻断了细胞在缺乏类固醇的培养基中孵育引起的NE分化和ERK磷酸化,从而证实了雄激素的特异性。此外,在添加5-α-还原酶抑制剂非那雄胺的完全培养基中培养LNCaP细胞,也能诱导NE分化和ERK磷酸化。这意味着主要的前列腺雄激素,双氢睾酮的消耗,作为这些影响的特定中介。与ERK相反,应激激活的MAPK成员c-Jun n -末端激酶和p38的磷酸化状态不受类固醇停药的影响。我们使用MEK抑制剂U0126来研究ERK在调节NE分化中的潜在作用。然而,U0126并没有逆转与类固醇消耗相关的NE分化,即使ERK磷酸化被抑制。在类固醇耗竭过程中,erbb酪氨酸激酶受体介导ERK磷酸化的作用也被研究。erb B1蛋白水平下降,erb B3蛋白水平和磷酸化保持不变,erb B2磷酸化蛋白水平升高。然而,细胞内erbb B2抗体的稳定表达并不能阻止与类固醇耗竭相关的ERK磷酸化上调。结论:雄激素消耗诱导LNCaP细胞中持续的erbb -独立ERK信号传导,然而,这一途径并不是相关NE分化所必需的。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 去求助
来源期刊
自引率
0.00%
发文量
0
期刊最新文献
新規PET検査の進歩 (特集 前立腺がんのスクリーニングと診断) PVP : 効率的な蒸散のために (特集 前立腺肥大症手術のコツとトラブルシューティング) 強度変調放射線治療(IMRT) (特集 前立腺がんに対する放射線治療最前線) -- (放射線治療の新規技術による治療成績と適応拡大) 専門医試験に役立つ前立腺知識 日本泌尿器科学会専門医資格試験2013年度解説 : 前立腺癌関連 QOL,患者の満足度 (特集 前立腺がんの手術) -- (ロボット支援手術について)
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
已复制链接
已复制链接
快去分享给好友吧!
我知道了
×
扫码分享
扫码分享
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1