Circular RNA circ_0000644 promotes papillary thyroid cancer progression via sponging miR-1205 and regulating E2F3 expression

ABSTRACT

The dysregulation of circular RNAs (circRNAs) facilitates the tumorigenesis of papillary thyroid carcinoma (PTC). This study was targeted at determining the functions and mechanism of circ_0000644 in regulating PTC development. Circ_0000644, microRNA-1205 (miR-1205) and E2F transcription factor 3 (E2F3) expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Actinomycin D (ActD) and Ribonuclease R (RNase R) assays were used to verify the circular characteristic of circ_0000644. After circ_0000644 was knocked down, PTC cell growth, migration, invasion and apoptosis were assessed by cell counting kit-8 (CCK-8) assay, Transwell assay and flow cytometry analysis, respectively. The regulating relationships among circ_0000644, E2F3 and miR-1205 were confirmed through RNA immunoprecipitation (RIP) assay and dual-luciferase reporter assay. Besides, the regulatory effects of circ_0000644 on the protein level of E2F3 was analyzed via Western blot. In PTC, circ_0000644 was highly expressed, and it was located mainly in the cytoplasm, and it had stable structure. The knockdown of circ_0000644 repressed PTC cell growth, migration, and invasion, and facilitated apoptosis. Circ_0000644 could directly interact with miR-1205 to repress the expression of miR-1205, and it served as a miR-1205 sponge to modulate E2F3 expression in PTC cells. Circ_0000644 up-regulates E2F3 expression via sponging miR-1205 to promote PTC progression.

KEYWORDS:

• Papillary thyroid carcinoma
• circ_0000644
• mir-1205
• E2F3

Disclosure statement

No potential conflict of interest was reported by the author(s).

Contribution of authors

All of the authors participates in designing the study, performing the experiments, analyzing the data, and preparing the manuscript. All of the authors read and approved the final manuscript.

Statement of data availability

The data used to support the findings of this study are available from the corresponding author upon request.

Statement of ethics

Our study was approved by the Ethics Committee of Harbin Medical University Cancer Hospital.

Additional information

Funding

This study was supported by the following funding: 1. The Youth Talent Support Program of Harbin Medical University Cancer Hospital (BJQN2018-01); 2. Heilongjiang Postdoctoral Foundation (LBH-Z17143); 3. The National Natural Scientific Foundation of China (81902954); 4. Postdoctoral Research Foundation of China (2018M630368); 5. Nn10 Program of Harbin Medical University Cancer Hospital; Heilongjiang Postdoctoral Scientific Research Developmental Fund (LBH-Q17122).