Dou Dongwei, Ren Xiaoyang, Han Mingli, Xu Xiaodong, Ge Xin, Gu Yuanting, Wang Xinxing, Zhao Song
Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe East Road, Erqi District, Zhengzhou, 450052 China.
Department of Information, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China.
Cancer Cell Int. 2020 Sep 14;20:454. doi: 10.1186/s12935-020-01547-7. eCollection 2020.
Triple-negative breast cancer (TNBC) is a clinically aggressive subtype of breast cancer with a bad prognosis. Chemotherapy is still the standard of care for TNBC treatment. Circular RNAs (CircRNAs) have been recently discovered to be closely involved in the initiation and development of human cancers. Herein, we focus our attention on the functions and underlying mechanisms of circUBE2D2 in TNBC progression and chemoresistance.
The expression of circUBE2D2, miR-512-3p, and cell division cycle associated 3 (CDCA3) mRNA were determined by qRT-PCR. CCK-8, colony formation, transwell and flow cytometry assays were performed to detect cell proliferation, migration, invasion and apoptosis. Western blot assay was utilized to measure the protein level of CDCA3. RNA pull-down, luciferase reporter and RIP experiments were employed to examine the possible regulatory mechanism of circUBE2D2.
CircUBE2D2 expression was elevated in TNBC tissues and cells. TNBC patients with high circUBE2D2 expression are inclined to present advanced TNM stage, lymph node metastasis and adverse prognosis. Knockdown of circUBE2D2 repressed cell proliferation, migration and invasion in vitro, and impeded tumor growth in vivo. Moreover, silencing of circUBE2D2 reduced doxorubicin resistance of TNBC cells. In-depth mechanism analysis revealed that circUBE2D2 served as a miRNA sponge to protect CDCA3 from the attack of miR-512-3p. Additionally, the tumor-suppressive effect induced by circUBE2D2 depletion was greatly impaired upon miR512-3p down-regulation or CDCA3 overexpression. Also, depletion of circUBE2D2 decreased the resistance to doxorubicin through regulating miR-512-3p/CDCA3 axis.
CircUBE2D2 promoted TNBC progression and doxorubicin resistance through acting as a sponge of miR-512-3p to up-regulate CDCA3 expression. Targeting circUBE2D2 combine with doxorubicin might be exploited as a novel therapy for TNBC.
三阴性乳腺癌（TNBC）是一种临床侵袭性乳腺癌亚型，预后较差。化疗仍是TNBC治疗的标准疗法。环状RNA（CircRNAs）最近被发现与人类癌症的发生和发展密切相关。在此，我们将注意力集中在circUBE2D2在TNBC进展和化疗耐药中的功能及潜在机制上。
通过qRT-PCR检测circUBE2D2、miR-512-3p和细胞分裂周期相关3（CDCA3）mRNA的表达。进行CCK-8、集落形成、Transwell和流式细胞术检测以检测细胞增殖、迁移、侵袭和凋亡。利用蛋白质免疫印迹法检测CDCA3的蛋白水平。采用RNA下拉、荧光素酶报告基因和RIP实验来研究circUBE2D2可能的调控机制。
circUBE2D2在TNBC组织和细胞中表达升高。circUBE2D2高表达的TNBC患者倾向于出现晚期TNM分期、淋巴结转移和不良预后。敲低circUBE2D2可抑制体外细胞增殖、迁移和侵袭，并在体内抑制肿瘤生长。此外，沉默circUBE2D2可降低TNBC细胞对阿霉素的耐药性。深入的机制分析表明，circUBE2D2作为一种miRNA海绵，保护CDCA3免受miR-512-3p的攻击。此外，下调miR512-3p或过表达CDCA3会极大地削弱circUBE2D2缺失诱导的肿瘤抑制作用。而且，circUBE2D2的缺失通过调节miR-512-3p/CDCA3轴降低了对阿霉素的耐药性。
circUBE2D2通过作为miR-512-3p的海绵上调CDCA3表达，促进TNBC进展和阿霉素耐药。靶向circUBE2D2联合阿霉素可能被开发为TNBC的一种新疗法。
