METHODS: Noggin expression in ER positive breast cancer cell lines (MCF-7 and T-47D) was determined under conditions of oestrogen deprivation and treatment with 17-β-oestradiol (E2). Activation of Smad1/5/8 in the oestrogen-regulated Noggin was examined using recombinant human BMP7 (rhBMP7) and a BMP receptor inhibitor (LDN-193189). The influence of Noggin on cellular functions was evaluated in MCF-7 and T-47D cell lines. Responses to tamoxifen and chemotherapy drugs were determined in MCF-7 and T-47D cells with Noggin over-expression using MTT assay.
RESULTS: Noggin expression was negatively correlated with ERα in breast cancers. Noggin was up-regulated upon oestrogen deprivation, an effect that was eliminated by E2 Furthermore, increased levels of phosphorylated Smad1/5/8 were observed in the oestrogen-deprived MCF-7 and T-47D cells, which was prevented by E2 and LDN-193189, respectively. BMP7-induced Noggin expression and activation of Smad1/5/8 was also prevented by E2 and LDN-193189. Noggin over-expression resulted in an increase in the proliferation of both MCF-7 and T-47D cells. MCF-7 and T-47D cells over-expressing Noggin exhibited a good tolerance to tamoxifen (TAM), DTX, and 5-FU, but the percentage of viable cells was higher compared with the controls.
CONCLUSIONS: Noggin expression can be repressed by oestrogen through inference with the BMP/Smad signalling. Over-expression of Noggin promotes the proliferation of MCF-7 and T-47D cells, contributing to drug resistance.
方法:在雌激素剥夺和用17-β-雌二醇(E2)处理的条件下,测定ER阳性乳腺癌细胞系(MCF-7和T-47D)中的Noggin表达。使用重组人BMP7(rhBMP7)和BMP受体抑制剂(LDN-193189)检查了雌激素调节的Noggin中Smad1/5/8的激活。在MCF-7和T-47D细胞系中评价Noggin对细胞功能的影响。使用MTT测定法在具有Noggin过表达的MCF-7和T-47D细胞中确定对他莫昔芬和化疗药物的反应。
结果:Noggin在乳腺癌中的表达与ERα呈负相关。Noggin在雌激素剥夺后上调,此外,E2消除了这种影响,在雌激素剥夺的MCF-7和T-47D细胞中观察到磷酸化Smad1/5/8水平升高,分别由E2和LDN-193189阻止。E2和LDN-193189也阻止了BMP7诱导的Noggin表达和Smad1/5/8的激活。Noggin过表达导致MCF-7和T-47D细胞的增殖增加。过表达Noggin的MCF-7和T-47D细胞对他莫昔芬(TAM)表现出良好的耐受性,DTX,5-FU,但活细胞的百分比高于对照组。
结论:Noggin的表达可以通过BMP/Smad信号的推断而被雌激素抑制。过表达Noggin促进MCF-7和T-47D细胞增殖,有助于耐药性。