circRNA RPPH1 Facilitates the Aggravation of Breast Cancer Development by Regulating miR-542-3p/ARHGAP1 Pathway

Background: Circular RNAs (circRNAs) have important roles in human malignancies, including breast cancer (BC). In this study, we explored the function of circRNA ribonuclease P RNA component H1 (circ_RPPH1) in BC development and clarify the mechanistic pathway. Materials and Methods: Expression of circ_RPPH1, microRNA-542-3p (miR-542-3p), and Rho GTPase-activating protein 1 (ARHGAP1) in BC tissues and cells was determined by quantitative real-time polymerase chain reaction or Western blot assay. The stability of circ_ RPPH1 was confirmed by RNase R and actinomycin D treatment. Cell viability and colony formation ability were measured by methyl thiazolyl tetrazolium ( MTT) assay and colony formation assay, respectively. Western blot analysis was also used to detect proliferation biomarker (Ki67) and epithelial- mesenchymal transition ( EMT) biomarkers (E-cadherin, N-cadherin, and vimentin). Flow cytometry and Transwell assays were performed to monitor cell apoptosis, migration, and invasion. The binding potency between miR-542-3p and circ_RPPH1 or ARHGAP1 was validated by dual-luciferase reporter assay. Functional role of circ_RPPH1 in vivo was investigated by xenograft tumor reporter assay. Results: Upregulation of circ_RPPH1 and ARHGAP1, and downregulation of miR-542-3p were detected in BC tissues and cells. circ_RPPH1 knockdown or miR-542-3p introduction inhibited BC cell proliferation and metastasis, while promoted apoptosis in vitro. circ_RPPH1 sponged miR-542-3p to upregulate ARHGAP1 expression, thereby affecting BC progression. Moreover, depletion of circ_RPPH1 suppressed tumor growth in vivo. Conclusions: circ_RPPH1 contributed to BC tumorigenesis by sponging miR-542-3p and upregulating ARHGAP1, affording a novel mechanistic pathway in BC development.

Automated summary

This study found that circ_RPPH1 promotes the development of breast cancer by sponging miR-542-3p and upregulating ARHGAP1 expression.