MicroRNA-221/222 Confers Tamoxifen Resistance in Breast Cancer by Targeting p27Kip1
MicroRNA-221/222 Confers Tamoxifen Resistance in Breast Cancer by Targeting p27Kip1
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DOI：
10.1074/jbc.m804612200
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发表时间：
2008-10-31
影响因子：
4.8
通讯作者：
Majumder, Sarmila
中科院分区：
文献类型：
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作者：
Miller, Tyler E.;Ghoshal, Kalpana;Majumder, Sarmila
我们探索了microRNAs （miRNAs）在获得对他莫昔芬（一种成功用于治疗雌激素受体阳性乳腺癌的药物）耐药中的作用。对他莫昔芬敏感（亲本）或耐药（4-羟他莫昔芬耐药（OHTR））的MCF-7细胞系的miRNA微阵列分析显示，与亲本MCF-7细胞相比，OHTR细胞中8种miRNA显著上调（> 1.8倍），7种miRNA显著下调（> 50%）。通过实时逆转录pcr验证了三种最有希望的上调mirna （miR-221， miR-222和miR181）和下调mirna （miR-21， miR-342和miR-489）的表达增加。与HER2/新阴性组织样本相比，在已知对内分泌治疗有耐药性的HER2/新阳性原发性人乳腺癌组织中，miR-221和miR-222的表达也显著（2倍）升高。miR-221/222的异位表达使亲代MCF-7细胞对他莫昔芬产生耐药性。已知miR-221/222的靶点细胞周期抑制剂p27（Kip1）的蛋白水平在OHTR细胞中降低了50%，在miR-221/222过表达的MCF-7细胞中降低了28-50%。此外，暴露于他莫昔芬的耐药OHTR细胞中p27（Kip1）的过表达导致细胞死亡增加。这是第一个证明miR-221/222表达与HER2/neu过表达之间关系的研究，这些肿瘤通常对他莫昔芬治疗有抗性。这一发现也为应用特异性mirna表达改变作为预测他莫昔芬耐药乳腺癌标志物提供了理论依据。
We explored the role of microRNAs (miRNAs) in acquiring resistance to tamoxifen, a drug successfully used to treat women with estrogen receptor-positive breast cancer. miRNA microarray analysis of MCF-7 cell lines that are either sensitive (parental) or resistant (4-hydroxytamoxifen-resistant (OHTR)) to tamoxifen showed significant (> 1.8-fold) up-regulation of eight miRNAs and marked down-regulation (> 50%) of seven miRNAs in OHTR cells compared with parental MCF-7cells. Increased expression of three of the most promising up-regulated (miR-221, miR-222, and miR181) and down-regulated (miR-21, miR-342, and miR-489) miRNAs was validated by real-time reverse transcription-PCR. The expression of miR-221 and miR-222 was also significantly (2-fold) elevated in HER2/neu-positive primary human breast cancer tissues that are known to be resistant to endocrine therapy compared with HER2/neu-negative tissue samples. Ectopic expression of miR-221/222 rendered the parental MCF-7 cells resistant to tamoxifen. The protein level of the cell cycle inhibitor p27(Kip1), a known target of miR-221/222, was reduced by 50% in OHTR cells and by 28-50% in miR-221/222-overexpressing MCF-7 cells. Furthermore, overexpression of p27(Kip1) in the resistant OHTR cells caused enhanced cell death when exposed to tamoxifen. This is the first study demonstrating a relationship between miR-221/222 expression and HER2/neu overexpression in primary breast tumors that are generally resistant to tamoxifen therapy. This finding also provides the rationale for the application of altered expression of specific miRNAs as a predictive tamoxifen-resistant breast cancer marker.