Huang Zhong-Feng, Tang Yu-Ling, Shen Zhao-Long, Yang Kai-Yan, Gao Kai
Department of Plastic Surgery, Xiangya Hospital of Central South University, Changsha 410008, Hunan Province, P. R. China.
Department of Hepatobiliary and Pancreatic Surgery, The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, P. R. China.
Mol Ther Oncolytics. 2021 Dec 11;24:497-506. doi: 10.1016/j.omto.2021.12.008. eCollection 2022 Mar 17.
Overexpressed ubiquitously expressed transcript (UXT) in breast tumors and derived cell lines modulated the transcriptional activity of estrogen receptor alpha. However, how UXT exerts its biological functions in the tumorigenicity of breast cancer remains largely unknown. Expressions of UXT and maternally expressed gene 3 (MEG3) were examined by qRT-PCR and Western blot. The capacity of cell proliferation, apoptosis, migration, and invasion was assessed using CCK-8, flow cytometry, and transwell assays. Methylation-specific PCR (MS-PCR) was employed to evaluate the methylation of the MEG3 imprinting control region. Co-immunoprecipitation was performed to verify the UXT/DNMT3b interaction. RNA immunoprecipitation (RIP) was subjected to assess the regulation of MEG3 on p53 activity. A xenograft tumor model was further conducted to certify the molecular mechanism. UXT was upregulated, while MEG3 was downregulated in breast cancer tissues and cell lines. UXT knockdown or MEG3 overexpression inhibited cell proliferation, promoted apoptosis, and weakened cell migration and invasion. Hypermethylation of the MEG3 imprinting control region was modulated by highly expressed DNMT3b. UXT inhibited MEG3 expression via recruiting DNMT3b to its imprinting control region. MEG3 positively regulated p53 activity. UXT negatively regulated the MEG3/p53 axis in a DNMT3b-dependent manner to promote tumor growth. UXT, a novel DNMT3b-binding protein, aggravates the progression of breast cancer through MEG3/p53 axis.
乳腺癌肿瘤及衍生细胞系中普遍表达的转录本（UXT）过表达可调节雌激素受体α的转录活性。然而，UXT如何在乳腺癌致瘤性中发挥其生物学功能仍 largely 未知。通过qRT-PCR和蛋白质免疫印迹法检测UXT和母源表达基因3（MEG3）的表达。使用CCK-8、流式细胞术和Transwell实验评估细胞增殖、凋亡、迁移和侵袭能力。采用甲基化特异性PCR（MS-PCR）评估MEG3印记控制区域的甲基化情况。进行免疫共沉淀以验证UXT/DNMT3b相互作用。进行RNA免疫沉淀（RIP）以评估MEG3对p53活性的调节作用。进一步构建异种移植肿瘤模型以验证分子机制。在乳腺癌组织和细胞系中，UXT上调，而MEG3下调。敲低UXT或过表达MEG3可抑制细胞增殖、促进凋亡，并减弱细胞迁移和侵袭。高表达的DNMT3b调节MEG3印记控制区域的高甲基化。UXT通过将DNMT3b募集到其印记控制区域来抑制MEG3表达。MEG3正向调节p53活性。UXT以DNMT3b依赖的方式负向调节MEG3/p53轴以促进肿瘤生长。UXT是一种新型的DNMT3b结合蛋白，通过MEG3/p53轴加重乳腺癌进展。
