circFNDC3B/miR-655-3p Axis Regulates the Cell Proliferation, Cell Cycle and Apoptosis of Breast Cancer Cells

TANG Lijuan¹, SONG Cheng², LIU Yilei³*, HUANG Ting¹

(¹Department of Breast Surgery, Sichuan People’s Hospital, the First Affiliated Hospital of University of Electronic Science and Technology, Chengdu 610072, China; ²Chengdu Shuangliu Airport Medical Aid Center, Chengdu 610000, China; ³Department of Gastrointestinal Surgery, First Affiliated Hospital of Chengdu Medical College, Chengdu 610513, China)

Abstract:

In this study, in order to explore the effect of circFNDC3B on breast cancer cells proliferation, cell cycle and apoptosis and its possible mechanism, RT-qPCR was first used to detect the expression of circFNDC3B and miR-655-3p in 83 breast cancer tissues and breast cancer cell lines (MCF-7, T47D, Bcap-37). And then circFNDC3B small interfering RNA, miR-655-3p mimic or miR-655-3p inhibitor was transfected into MCF-7 cells, or circFNDC3B small interfering RNA and miR-655-3p inhibitor were co-transfected into MCF-7 cells. CCK-8 method was used to detect cell proliferation. Flow cytometry was used to detect cell apoptosis and cycle. Western blot was used to detect the protein expression of CyclinD1 and Cleaved-caspase-3. The dual luciferase reporter gene experiment verified the regulatory relationship between miR-655-3p and circFNDC3B. The results showed that the expression of circFNDC3B in breast cancer tissues and cell lines were increased (P<0.05), but the expression of miR-655-3p were decreased (P<0.05). After down-regulating circFNDC3B or up-regulating miR-655-3p, the proliferation activity of MCF-7 cells and the protein expression of CyclinD1 decreased, and cell cycle progression was blocked, but the apoptosis rate and the protein expression of Cleaved-caspase-3 increased, and the difference were statistically significant (P<0.05). circFNDC3B negatively regulated the expression of miR-655-3p. The effects of down-regulation of miR-655-3p on the proliferation, cell cycle and apoptosis of MCF-7 cells were opposite to those of up-regulation of miR-655-3p. Downregulation of miR-655-3p reversed the effect of down-regulation of circFNDC3B on the proliferation, cell cycle and apoptosis of MCF-7 cells. This indicated that circFNDC3B might promote the proliferation and cell cycle progression of breast cancer cells, and hinder cell apoptosis by inhibiting the expression of miR-655-3p.

CSTR: 32200.14.cjcb.2021.06.0018