Ma Siyuan, Zhang Bochao, Pu Chun
Clinical Laboratory, Xuancheng City Central Hospital, Xuancheng 242000, China.
College of Laboratory Medicine, Wannan Medical College, Wuhu 241000, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2025 Aug 20;45(8):1682-1696. doi: 10.12122/j.issn.1673-4254.2025.08.13.
To investigate the role of circular RNA circ_0000437 in regulating biological behaviors of breast cancer cells and the molecular mechanism.
Breast cancer MCF-7 and MDA-MB-231 cells were transfected with sh-circ_0000437, mimics, inhibitor, si-CTPS1, or their respective negative controls. qRT-PCR was used to detect the expression levels of circ_0000437, let-7b-5p, CTPS1, Notch1, Hes1, and Numb in breast cancer cell lines and tissues. RNase R digestion was used to confirm the circular structure of circ_0000437 and its subcellular localization in the breast cancer cells was determined by cellular distribution analysis. The changes in proliferation, invasion and migration of the transfected cells were assessed using CCK-8 assay, Transwell assay and scratch assay. Dual-luciferase reporter gene and RNA immunoprecipitation assays were employed to validate binding interactions among circ_0000437, let-7b-5p, and CTPS1. The cellular expressions of CTPS1, E-cadherin, N-cadherin, and vimentin proteins were detected with Western blotting. A tumor-bearing mouse model was used to verify the oncogenic mechanism of circ_0000437 and CTPS1.
Circ_0000437 and CTPS1 were upregulated while let-7b-5p was downregulated in breast cancer tissues and cell lines. Circ_0000437 or CTPS1 knockdown obviously suppressed breast cancer cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT). Overexpression of let-7b-5p produced similar inhibitory effects, whereas inhibition of let-7b-5p significantly enhanced malignant behaviors of the cells. In the tumor-bearing mouse models, circ_0000437 knockdown significantly suppressed tumor growth, but co-transfection of the cells with pcDNA-CTPS1 accelerated tumor growth. Binding sites were identified between circ_0000437 and let-7b-5p and between let-7b-5p and CTPS1, and circ_0000437, let-7b-5p, and CTPS1 showed functional interactions in breast cancer cells.
Circ_0000437 is upregulated in breast cancer tissues and cells, and its high expression promotes proliferation, invasion, migration and EMT of breast cancer cells through the let-7b-5p/CTPS1 axis.
探讨环状RNA circ_0000437在调控乳腺癌细胞生物学行为中的作用及其分子机制。
用sh-circ_0000437、模拟物、抑制剂、si-CTPS1或它们各自的阴性对照转染乳腺癌MCF-7和MDA-MB-231细胞。采用qRT-PCR检测乳腺癌细胞系和组织中circ_0000437、let-7b-5p、CTPS1、Notch1、Hes1和Numb的表达水平。用RNase R消化法确认circ_0000437的环状结构，并通过细胞分布分析确定其在乳腺癌细胞中的亚细胞定位。采用CCK-8法、Transwell法和划痕法评估转染细胞增殖、侵袭和迁移的变化。采用双荧光素酶报告基因和RNA免疫沉淀试验验证circ_0000437、let-7b-5p和CTPS1之间的结合相互作用。用蛋白质印迹法检测CTPS1、E-钙黏蛋白、N-钙黏蛋白和波形蛋白的细胞表达。采用荷瘤小鼠模型验证circ_0000437和CTPS1的致癌机制。
circ_0000437和CTPS1在乳腺癌组织和细胞系中上调，而let-7b-5p下调。circ_0000437或CTPS1敲低明显抑制乳腺癌细胞增殖、侵袭、迁移和上皮-间质转化（EMT）。let-7b-5p过表达产生类似的抑制作用，而抑制let-7b-5p显著增强细胞的恶性行为。在荷瘤小鼠模型中,circ_0000437敲低显著抑制肿瘤生长，但细胞与pcDNA-CTPS1共转染加速肿瘤生长。在circ_0000437与let-7b-5p之间以及let-7b-5p与CTPS之间发现了结合位点，并且circ_0000437、let-7b-5p和CTPS1在乳腺癌细胞中显示出功能相互作用。
circ_0000437在乳腺癌组织和细胞中上调，其高表达通过let-7b-5p/CTPS1轴促进乳腺癌细胞增殖、侵袭、迁移和EMT。
