Research Paper Volume 13, Issue 8 pp 12207—12223

Anti-oncogenic effects of SOX2 silencing on hepatocellular carcinoma achieved by upregulating miR-222-5p-dependent CYLD via the long noncoding RNA CCAT1

Jian Pu1, *, , Xianjian Wu2, *, , Yi Wu2, , Zesheng Shao2, , Chunying Luo3, , Qianli Tang1, , Jianchu Wang1, , Huamei Wei3, &, , Yuan Lu1,2, &, ,

  • 1 Department of Hepatobiliary Surgery, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, P.R. China
  • 2 Graduate College of Youjiang Medical University for Nationalities, Baise 533000, P.R. China
  • 3 Department of Pathology, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, P.R. China
* Co-first authors

Received: February 18, 2020       Accepted: May 1, 2020       Published: March 22, 2021
How to Cite

Copyright: © 2021 Pu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


In this study, we determined the involvement of SOX2 and its downstream signaling molecules in hepatocellular carcinoma (HCC) progression. We carried out lentiviral transfection in HepG2 cells to determine the roles of SOX2, CCAT1, EGFR, miR-222-5p, and CYLD in HepG2 cells. We first determined the interaction between SOX2 and CCAT1 and that between miR-222-5p and CYLD and their effect on tumor growth in vivo was analyzed in HCC-xenograft bearing nude mice xenografts. SOX2 and CCAT1 were highly expressed in HCC tissues and HepG2 cells. SOX2 bound to the regulatory site of CCAT1. Silencing of SOX2 or CCAT1 inhibited HepG2 cell proliferation, migration, and invasion as well as decreased the expression of CCAT1 and EGFR. CCAT1 silencing reduced EGFR expression, but EGFR expression was increased in HCC tissues and HepG2 cells, which promoted proliferation, migration, and invasion in vitro. EGFR upregulated miR-222-5p, leading to downregulation of CYLD. miR-222-5p inhibition or CYLD overexpression repressed cell functions in HepG2 cells. SOX2 silencing decreased CCAT1, EGFR, and miR-222-5p expression but increased CYLD expression. Loss of SOX2 also reduced the growth rate of tumor xenografts. In summary, SOX2-mediated HCC progression through an axis involving CCAT1, EGFR, and miR-222-5p upregulation and CYLD downregulation.


HCC: Hepatocellular carcinoma; SOX2: Sex determining region Y-box 2; lncRNA: Long non-coding RNA; CCAT1: colon cancer-associated transcript 1; EGFR: epidermal growth factor receptor; miRs: microRNAs; CYLD: Cylindromatosis; TNM: Tumor-node-metastasis; shRNA: short hairpin RNA; SPF: specific pathogen-free; DMEM: Dulbecco’s Modified Eagle Medium; UTR: untranslated region; WT: wild type; PBS: phosphate buffer saline.