Aberrant expression of circular RNA DHPR facilitates tumor growth and metastasis by regulating the RASGEF1B/RAS/MAPK axis in hepatocellular carcinoma

Zeyi Guo  ^{1   2} , Qingyu Xie  ^{1   2   3} , Yanping Wu  ^{1   2} , Haiyu Mo  ⁴ , Jiajun Zhang  ^{1   2} , Guolin He  ^{1   2} , Zhongzhe Li  ^{1   2} , Luxiang Gan  ^{1   2} , Lei Feng  ^{1   2} , Ting Li  ^{1   2} , Yi Wang  ^{1   2} , Yu Fu  ^{1   2} , Lei Cai  ^{1   2} , Shao Li  ^{1   2} , Chao Yu  ⁵ , Yi Gao  ^{6   7} , Mingxin Pan  ^{8   9} , Shunjun Fu  ^{10   11}

Affiliations

Affiliations

• ¹ Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510000, P. R. China.
• ² Research Centre for Artificial Organ and Tissue Engineering & Institute of Regenerative Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, 510000, P. R. China.
• ³ Center of Pancreas, Guangdong Provincial People’s Hospital, Southern Medical University, Guangzhou, 510000, P. R. China.
• ⁴ Department of Medical Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510000, P. R. China.
• ⁵ Department of General Surgery, Zhujiang hospital, Southern Medical University, Guangzhou, 510000, P. R. China.
• ⁶ Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510000, P. R. China. gaoyi@smu.edu.cn.
• ⁷ Research Centre for Artificial Organ and Tissue Engineering & Institute of Regenerative Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, 510000, P. R. China. gaoyi@smu.edu.cn.
• ⁸ Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510000, P. R. China. pmxwxy@sohu.com.
• ⁹ Research Centre for Artificial Organ and Tissue Engineering & Institute of Regenerative Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, 510000, P. R. China. pmxwxy@sohu.com.
• ¹⁰ Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, 510000, P. R. China. fsj103@163.com.
• ¹¹ Research Centre for Artificial Organ and Tissue Engineering & Institute of Regenerative Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, 510000, P. R. China. fsj103@163.com.

• PMID: 37099250
• DOI: 10.1007/s13402-023-00814-9

Abstract

Background: Circular RNAs (circRNAs) are noncoding RNAs. Accumulating evidence suggests that circRNAs play a critical role in human biological processes, especially tumorigenesis, and development. However, the exact mechanisms of action of circRNAs in hepatocellular carcinoma (HCC) remain unclear.

Methods: Bioinformatic tools and RT-qPCR were used to identify the role of circDHPR, a circRNA derived from the dihydropteridine reductase (DHPR) locus, in HCC and para-carcinoma tissues. Kaplan-Meier analysis and the Cox proportional hazard model were used to analyze the correlation between circDHPR expression and patient prognosis. Lentiviral vectors were used to establish stable circDHPR-overexpressing cells. In vitro and in vivo studies have shown that tumor proliferation and metastasis are affected by circDHPR. Mechanistic assays, including Western blotting, immunohistochemistry, dual-luciferase reporter assays, fluorescence in situ hybridization, and RNA immunoprecipitation, have demonstrated the molecular mechanism underlying circDHPR.

Results: CircDHPR was downregulated in HCC, and low circDHPR expression was associated with poor overall survival and disease-free survival rates. CircDHPR overexpression inhibits tumor growth and metastasis in vitro and in vivo. Further systematic studies revealed that circDHPR binds to miR-3194-5p, an upstream regulator of RASGEF1B. This endogenous competition suppresses the silencing effect of miR-3194-5p. We confirmed that circDHPR overexpression inhibited HCC growth and metastasis by sponging miR-3194-5p to upregulate the expression of RASGEF1B, which is regarded as a suppressor of the Ras/MAPK signaling pathway.

Conclusions: Aberrant circDHPR expression leads to uncontrolled cell proliferation, tumorigenesis, and metastasis. CircDHPR may serve as a biomarker and therapeutic target for HCC.

Keywords: Circular RNA; DHPR; Hepatocellular carcinoma; RASGEF1B; Ras/MAPK.