He Xu, Chen Jie, Yie Shang-mian, Ye Shang-rong, Dong Dan-Dan, Li Ke
1Core Laboratory, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.
2Research and Development Center, Sichuan HeLi Bio-pharmaceutical Co. Ltd., Sichuan HeBang Group, Chengdu, Sichuan, China.
Nucleic Acid Ther. 2015 Jun;25(3):152-61. doi: 10.1089/nat.2014.0521. Epub 2015 Mar 3.
Estrogen receptors (ERs) are overexpressed in approximately 70% of breast cancer cases, and they play an important role in tumorigenesis. ERs are strong predictive factors for measuring responses to hormonal therapies. Aptamers are short and single stranded oligonucleotides that are able to recognize target molecules with high affinity. In the present study, we selected and synthesized an oligonucleotide, which has a similar sequence to estrogen response element in the Xenopus Vitellogenin A2 gene. The synthesized oligonucleotide was evaluated by using immunostaining of paraffin-embedded breast cancer tissues and treating MCF-7 human mammary carcinoma cell line in vitro. We found that the synthesized oligonucleotide had a high binding affinity to ER similar to estradiol. Using a specific anti-ER antibody as a standard control, we showed that the synthesized oligonucleotide specifically recognized and immunostained tumor cells of breast cancer without cross-reaction with normal tissues. The overall agreement of ER detection between the anti-ER antibody and the ER aptamer was 97.1% (kappa value=0.943; 95% CI=0.879-1.006; p<0.002). Similar to tamoxifen or fulvestrant, the oligonucleotide also had an inhibitory effect on cell proliferation of MCF-7 cell line in a dose- and time-dependent fashion but had no cytotoxic effect on human normal mammary epithelial cells. Therefore, the synthesized oligonucleotide may be used as an aptamer for immunostaining of paraffin-embedded tissue sections for breast cancer diagnosis, as well as a potential ER antagonist in the treatment of breast cancer.
雌激素受体（ERs）在大约70%的乳腺癌病例中过度表达，它们在肿瘤发生中起重要作用。ERs是衡量激素治疗反应的强有力预测因子。适体是能够以高亲和力识别靶分子的短单链寡核苷酸。在本研究中，我们筛选并合成了一种寡核苷酸，其序列与非洲爪蟾卵黄蛋白原A2基因中的雌激素反应元件相似。通过对石蜡包埋的乳腺癌组织进行免疫染色以及体外处理MCF-7人乳腺癌细胞系来评估合成的寡核苷酸。我们发现合成的寡核苷酸对ER具有与雌二醇相似的高结合亲和力。以特异性抗ER抗体作为标准对照，我们表明合成的寡核苷酸能特异性识别并免疫染色乳腺癌肿瘤细胞，而不与正常组织发生交叉反应。抗ER抗体与ER适体之间ER检测的总体一致性为97.1%（kappa值 = 0.943；95% CI = 0.879 - 1.006；p < 0.002）。与他莫昔芬或氟维司群相似，该寡核苷酸也对MCF-7细胞系的细胞增殖具有剂量和时间依赖性抑制作用，但对人正常乳腺上皮细胞无细胞毒性作用。因此，合成的寡核苷酸可作为石蜡包埋组织切片免疫染色用于乳腺癌诊断的适体，以及作为乳腺癌治疗中的潜在ER拮抗剂。
