雌二醇與尼古丁透過 PI3K/Akt 和 MAPK 訊息傳遞路徑促進 MCF-7
人類乳腺癌細胞中
尼古丁受器 nAChR alpha9 基因表現的機制探討
17 beta-estradiol (E2) and Nicotine Can Increase Nicotinic
Acetylcholine Receptor alpha9 ( nAChR alpha9 ) Gene Expression
Through PI3K/Akt and MAPK Signaling Transduction Pathway
in MCF-7 Human Breast Cancer Cells
中文摘要 本研究主要目的是探討乳癌、雌性素、尼古丁三者的關聯性。欲知雌二醇和尼古 丁如何調控 MCF-7 乳腺癌細胞株中尼古丁受器 nAChR alpha9 的基因表現與兩者 在細胞內共同的訊息傳遞路徑，並且尋找主要影響尼古丁受器基因轉錄的轉錄因 子。當 MCF-7 細胞株給予生理濃度的雌二醇 ( 1 nM ) 和尼古丁 ( 10 microM ) 時，其尼古丁受器的 mRNA 可在 48 小時後明顯增加。而在細胞訊息傳遞方面： 使用 PI3K 抑制劑 LY 294002，以及 MAPK 抑制劑 PD 98059 和 SP 600125，可抑 制住兩者共同的訊息傳遞路徑。因此歸納出兩者共同訊息傳遞路徑為 PI3K/ Akt/p-ER alpha( Ser 167 ) 以及 MEK1,2/ ERK1,2/JNK1,2/ p-ER alpha( Ser 118 ) 。 此外，運用 Serial deletion luciferase activity assay 和 Site-directed mutagenesis assay 發現雌二醇影響尼古丁受器基因轉錄的轉錄因子結合位置為 VDR 和 AP-1，而尼 古丁影響尼古丁受器基因轉錄的轉錄因子結合位置為 AP-1。
英文摘要
The purpose of this investigation is to study the effects of 17 beta-estradiol and nicotine on nicotinic acetylcholine receptor alpha9 ( nAChR alpha9 ) gene expression and the cross-linking signaling pathways in MCF-7 human breast cancer cells. Using physiological concentrations of 17 beta-estradiol ( 1 nM ) and nicotine ( 10 microM ) could increase nAChR alpha9 mRNA expression after 48 hours treatment. Using PI3K inhibitor, LY 294002, could block both cross-linking pathway in MCF-7. PD 98059 and SP 600 125, inhibitors of mitogen-activated protein kinase (MAPK) pathways, were also involved in both cross-linking pathways in MCF-7. Using serial deletion luciferase activity assay and site-directed mutagenesis assay to predict the most important transcription factor binding sites on nAChR alpha9 gene promoter. These results demonstrate the cross-linking pathways of 1 nM 17 beta-estradiol and 10 microM nicotine were through PI3K/Akt/p-ER alpha( Ser 167 ) and MEK1, 2/ ERK1,2/JNK1,2/p-ER alpha( Ser 118 ). The most important transcription factor
binding sites on nAChR alpha9 gene promoter for 17 beta-estradiol are Vitamin D Receptor ( VDR ) and Activated Protein- 1 ( AP-1 ). The most one for nicotine is Activated Protein- 1 ( AP-1 ).
