State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences and Graduate School, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2010 Feb 2;5(2):e9013. doi: 10.1371/journal.pone.0009013.
Recently, a novel variant of ER-alpha, ER-alpha36 was identified and cloned. ER-alpha36 lacks intrinsic transcription activity and mainly mediates nongenomic estrogen signaling. Here, we studied the role of nongenomic estrogen signaling pathways mediated by ER-alpha36 in tamoxifen resistance and agonist action.
The cellular localization of ER-alpha36 was examined by immunofluorescence in MCF-7 cells and Hec1A cells. MCF-7 breast cancer cells, MCF-7 cells expressing recombinant ER-alpha36 (MCF-7/ER36), Hec1A endometrial cancer cells and Hec1A cells with siRNA knockdown of ER-alpha36 (Hec1A/RNAiER36) were treated with 17beta-estradial (E2) and tamoxifen (TAM) in the absence and presence of kinase inhibitor U0126 and LY294002. We examined phosphorylation of signaling molecules and the expression of c-Myc by immunoblotting, and tumor cell growth by MTT assay.
ER variant ER-alpha36 enhances TAM agonist activity through activation of the membrane-initiated signaling pathways in endometrial cancer, and that ER-alpha36 is involved in de novo and acquired TAM resistance in breast cancer.
最近，一种新型的 ER-α变体 ER-α36 被鉴定和克隆。ER-α36 缺乏内在转录活性，主要介导非基因组雌激素信号。在这里，我们研究了由 ER-α36 介导的非基因组雌激素信号通路在他莫昔芬耐药和激动剂作用中的作用。
通过免疫荧光在 MCF-7 细胞和 Hec1A 细胞中检测 ER-α36 的细胞定位。用 17β-雌二醇（E2）和他莫昔芬（TAM）处理 MCF-7 乳腺癌细胞、表达重组 ER-α36 的 MCF-7 细胞（MCF-7/ER36）、子宫内膜癌 Hec1A 细胞和用 siRNA 敲低 ER-α36 的 Hec1A 细胞（Hec1A/RNAiER36），在存在和不存在激酶抑制剂 U0126 和 LY294002 的情况下。通过免疫印迹检测信号分子的磷酸化和 c-Myc 的表达，通过 MTT 测定检测肿瘤细胞的生长。
ER 变体 ER-α36 通过激活子宫内膜癌中的膜起始信号通路增强了 TAM 的激动剂活性，并且 ER-α36 参与了乳腺癌中的新的和获得性 TAM 耐药。
