PO.TB03.03 · 肿瘤生物学
一种新型多西环素诱导型乳腺EZH2过表达模型的特征分析
Characterization of a novel doxycycline inducible model of EZH2 overexpression in mammary glands
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：Zeste同源物增强子2（EZH2）是一种组蛋白甲基转移酶，也是多梳抑制复合物2（PRC2）的催化亚基，负责在赖氨酸27处对组蛋白H3进行三甲基化（H3K27me3）。在人类乳腺癌中，EZH2过表达是一个独立的预后标志物，并与ER和PR阴性表达显著相关。然而，EZH2过表达在乳腺癌发生中的时机和功能意义仍不清楚。为此，我们在FVB小鼠中构建了一个乳腺EZH2过表达的条件性模型。
方法：我们在FVB背景下构建了一个多西环素诱导型转基因小鼠模型MMTV-rtTA;TetO-EZH2及相应对照，以实现EZH2在乳腺上皮细胞内的靶向过表达。我们向10周龄雌性小鼠的饮用水中给予多西环素（2 mg/mL）96小时，并在饲料中给予6个月，以诱导EZH2过表达。在此年龄，乳腺已成熟。在研究终点，切除乳腺并采用全组织铺片胭脂红明矾染色分析以评估导管结构。将乳腺包埋于石蜡中，并使用抗EZH2抗体通过组织病理学和免疫染色进行研究。
结果：在成年小鼠中诱导EZH2表达96小时导致导管分支数目相较于诱导和未诱导对照增加。长期EZH2诱导还导致过度分支表型以及在全腺体胭脂红明矾染色中观察到的乳腺上皮结节的形成，这些在对照中并不存在。包括组织病理学评估、免疫染色和空间分析在内的其他研究正在进行中，以进一步表征EZH2诱导的生物学和分子后果。
结论：我们展示了一种新型可诱导EZH2过表达模型在成年小鼠乳腺中的建立及其初步特征分析。初步研究显示，EZH2过表达导致导管内上皮增生和导管过度分支，重现了人类癌前病变。未来研究将把这一新型模型与其他乳腺癌小鼠模型相结合，以探索EZH2过表达对肿瘤起始和进展的后果。
查看英文原文 English abstract
Background: Enhancer of Zeste Homolog 2 (EZH2) is a histone methyltransferase and catalytic subunit of the Polycomb Repressive Complex 2 (PRC2), responsible for trimethylating histone H3 at lysine 27 (H3K27me3). In human breast cancer, EZH2 overexpression is an independent prognostic marker and is significantly associated with negative ER and PR expression. However, the timing and functional significance of EZH2 overexpression in breast cancer development is still unclear. Towards this, we generated a conditional model of EZH2 overexpression to the mammary gland in FVB mice.
Methods: We generated a doxycycline-inducible transgenic mouse model MMTV-rtTA;TetO-EZH2 and appropriate controls in an FVB background to enable targeted overexpression of EZH2 within mammary epithelial cells. We administered doxycycline (2 mg/mL) in the drinking water to 10-week-old female mice for 96 hours and in chow for 6 months, to induce EZH2 overexpression. At this age, the mammary glands are mature. At study endpoints, mammary glands were resected and analyzed using whole-mount carmine alum staining to assess ductal architecture. Mammary glands were embedded in paraffin and studied by histopathology and immunostaining using anti-EZH2 antibodies.
Results: Induction of EZH2 expression in adult mice for 96 hours led to increased numbers of ductal branches compared to induced and uninduced controls. Long-term EZH2 induction also resulted in a hyperbranching phenotype and development of mammary epithelial nodules observed in carmine alum stains of whole glands, which were not present in the controls. Additional studies, including histopathological evaluation, immunostaining, and spatial analyses are underway to further characterize the biological and molecular consequences of EZH2 induction.
Conclusions: We present the development and initial characterization of a novel inducible EZH2 overexpression model in the mammary glands of adult mice. Preliminary studies show that EZH2 overexpression results in intraductal epithelial hyperplasia and ductal hyperbranching recapitulating human preneoplastic lesions. Future studies will combine this novel model with other breast cancer mouse models to explore the consequences of EZH2 overexpression on tumor initiation and progression.
利益披露 Disclosure
A. Eido, None..
M. E. Gonzalez, None..
L. Syu, None.