探究雷诺昔芬（RAL）对乳腺癌中过表达雌激素受体（ER）β1的MDA-MB-231细胞的抑制作用。

用含ERβ1基因的HIV慢病毒转染乳腺癌MDA-MB-231细胞，获得稳定表达ERβ1的乳腺癌细胞株。采用RT-PCR法检测转染细胞中ERβ1 mRNA的表达水平，Western blotting法检测细胞中ERβ1蛋白的表达水平；各细胞亚型分别于0、1、10 μmol/L的RAL共培养48 h，观察RAL对ERβ1高表达细胞株及对照细胞株治疗作用的差异。

HIV慢病毒转染后细胞绿色荧光表达效率达到90%以上；RT-PCR检测显示阳性转染组MDA-MB-231/ERβ1细胞中ERβ1 mRNA水平较阴性转染组提高了12.9倍（P<0.05）；阳性转染组细胞中ERβ1蛋白水平也相应提高；细胞实验表明高浓度（10 μmol/L）的RAL对MDA-MB-231细胞有明显的增殖抑制作用，特别是对ERβ1高表达细胞株的抑制作用更加明显（F=9.273，P=0.015）。

在乳腺癌MDA-MB-231细胞中，ERβ1高表达可以使细胞对RAL更加敏感。

To up-regulate ERβ1 mRNA in breast cancer cells, and to explore the inhibiting effect of raloxifene (RAL) on MDA-MB-231 cell which has the high expression of ERβ1.

We used HIV lentivirus containing ERβ1 gene to infect breast cancer cell line of MDA-MB-231, and established cell-line stably over-expressing ERβ1 gene. Fluorescence microscopy was used to show the transfected cells of which the eGFP was positive. Then we identified the ERβ1 gene expression on the levels of mRNA and protein by RT-PCR and Western blotting. All cell subtypes were cultured with increasing concentration of RAL (0, 1, 10 μmol/L) for 48 h, the difference of therapeutic effects among the MDA-MB-231/ERβ1, MDA-MB-231/eGFP and MDA-MB-231 were detected.

Fluorescence microscopy showed that more than 90% of transfected cells by the HIV lentivirus were green fluorescence positive. RT-PCR test showed that the levels of ERβ1 mRNA in MDA-MB-231/ERβ1 cells were increased 12.9 times respectively compared with parental cells (P<0.05). Western blotting showed that ERβ1 protein levels were also increased correspondingly. Cell experiment showed that high dose (10 μmol/L) of RAL inhibited proliferation of all MDA-MB-231 sub-lines, and the greater extent was observed when ERβ1 over-expressed (F=9.273, P=0.015).

The sensitivity to RAL for breast cancer cell of MDA-MB-231 can be increased by up-regulating ERβ1 level.