Circ_0035483 Functions as a Tumor Promoter in Renal Cell Carcinoma via the miR-31-5p-Mediated HMGA1 Upregulation

Zheng Liu,^1,* Ronghai Wang,^2,* Guangze Zhu<sup>3

1</sup>Department of Traditional Chinese Medicine and Acupuncture, Central Hospital of Baoji, Baoji City, Shaanxi Province, People’s Republic of China; ²Department of Urology, Linzi District People’s Hospital, Zibo City, Shandong Province, People’s Republic of China; ³Department of Clinical Laboratory Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun City, Jilin Province, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Guangze Zhu
Department of Clinical Laboratory Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, No. 1478 Gongnong Road, Chaoyang District, Changchun, Jilin Province 130021, People’s Republic of China
Tel/Fax +86 431-86177939
Email zhugz0820@126.com

Background: Renal cell carcinoma (RCC) that originates from the proximal renal tubules is the most common cancer of the human kidney. Increasing circRNA/miRNA/mRNA networks have been found in RCC regulation. This study will explore the regulatory relation of circular RNA (circRNA) circ_0035483, microRNA-31-5p (miR-31-5p) and high mobility group A1 (HMGA1).
Methods: The levels of circ_0035483, miR-31-5p and HMGA1 were measured by real-time polymerase chain reaction (qRT-PCR) or Western blot. Cell proliferation was determined using Cell Counting Kit-8 (CCK-8) and colony formation assays. Cell migration and invasion were assessed by transwell assay. HMGA1 and epithelial–mesenchymal transition (EMT)-related protein levels were quantified using Western blot. Glycolytic metabolism was evaluated by glucose consumption and lactate production. The interaction between targets was confirmed via dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. In vivo experiment was performed through the establishment of xenograft models in mice.
Results: Circ_0035483 expression was upregulated in RCC tissues and cells. The inhibitory effects on RCC cell proliferation, migration, invasion, EMT and glycolysis were induced after circ_0035483 was downregulated. MiR-31-5p was identified as a target of circ_0035483 and miR-31-5p upregulation was related to the function of circ_0035483 knockdown in RCC cells. Additionally, miR-31-5p targeted HMGA1 and inhibited the malignant behaviors of RCC cells by negatively regulating HMGA1. Moreover, HMGA1 expression was regulated by circ_0035483 via targeting miR-31-5p. Circ_0035483 also affected tumor growth in vivo by relying on the miR-31-5p/HMGA1 axis.
Conclusion: These findings clarified that the tumor-promoting function of circ_0035483 in RCC was partly achieved by regulating the miR-31-5p/HMGA1 axis.

Keywords: circ_0035483, renal cell carcinoma; RCC, miR-31-5p, HMGA1