Guan Bing, Li Qing, Zhang Hui-Zhen, Yang Hai-Sheng
Department of Pathology, Shanghai 6th People's Hospital Jinshan Branch, Shanghai, China.
Department of Pathology, Shanghai Pudong New Area People's Hospital, Shanghai, China.
Front Oncol. 2021 Jan 20;10:602694. doi: 10.3389/fonc.2020.602694. eCollection 2020.
Breast cancer is the most common type of cancer diagnosed among women, and basal-like breast carcinoma (BLBC) has been associated with a more aggressive histology, poorer prognosis, and non-responsiveness to hormone therapy. In the present study, the role and molecular mechanism of circular (circ)_NOTCH3 in the development and progression for BLBC was identified. circ_RNAs array was used to screen the ectopic expression of hsa_circ_0109177 (circ_NOTCH3) in BLBC. RT-qPCR was conducted to evaluate the circ_NOTCH3 expression in BLBC tissues and paired normal tissues, as well as related cell lines. Cell function changes were analyzed following circ_NOTCH3 or micro (mi)RNA overexpression or co-expression. Bioinformatics analysis and dual-luciferase reporter assay were performed to predict and verify the binding sites between circ_NOTCH3 and miRNAs. Gene expression changes were assessed using western blotting. circ_NOTCH3 had a significantly higher expression in BLBC tissues and cell lines. The upregulation of circ_NOTCH3 promoted the proliferation, migration, invasion and inhibited the apoptosis for BLBC cells. The opposite results were observed following miR-205-5p overexpression. However, the co-expression of circ_NOTCH3 and miR-205-5p resulted in those restoration. circ_NOTCH3 is capable of binding to miR-205-5p, and upregulating its target gene KLF12, which can be downregulated by miR-205-5p overexpression and restored by the co-expression of circ_NOTCH3 and miR205-5p. circ_NOTCH3, being an protooncogene and a powerful biomarker, can function as a sponge, compete with miR-205-5p, modulate KLF12 expression, and promote the development and progression of BLBC.
乳腺癌是女性中诊断出的最常见癌症类型，而基底样乳腺癌（BLBC）与更具侵袭性的组织学、更差的预后以及对激素治疗无反应有关。在本研究中，确定了环状（circ）_NOTCH3在BLBC发生发展中的作用和分子机制。使用circ_RNAs阵列筛选BLBC中hsa_circ_0109177（circ_NOTCH3）的异位表达。进行RT-qPCR以评估circ_NOTCH3在BLBC组织、配对的正常组织以及相关细胞系中的表达。在circ_NOTCH3或微小（mi）RNA过表达或共表达后分析细胞功能变化。进行生物信息学分析和双荧光素酶报告基因检测以预测和验证circ_NOTCH3与miRNA之间的结合位点。使用蛋白质印迹法评估基因表达变化。circ_NOTCH3在BLBC组织和细胞系中的表达显著更高。circ_NOTCH3的上调促进了BLBC细胞的增殖、迁移、侵袭并抑制了其凋亡。在miR-205-5p过表达后观察到相反的结果。然而，circ_NOTCH3和miR-205-5p的共表达导致了这些恢复。circ_NOTCH3能够与miR-205-5p结合，并上调其靶基因KLF12，KLF12可被miR-205-5p过表达下调，并通过circ_NOTCH3和miR205-5p的共表达恢复。circ_NOTCH3作为一种原癌基因和强大的生物标志物，可作为海绵发挥作用，与miR-205-5p竞争，调节KLF12表达，并促进BLBC的发生发展。
