CircRFX3 Up-regulates Its Host Gene RFX3 to Facilitate Tumorigenesis and Progression of Glioma

J Mol Neurosci. 2022 Jun;72(6):1195-1207. doi: 10.1007/s12031-022-02005-x. Epub 2022 Apr 13.

Abstract

Background: Glioma is classified as one of the most common types of primary brain tumors. The high expression of CircRFX3 has been found in glioma. However, its functional roles in glioma and underlying mechanism remain unknown.

Purpose: Our study aimed to explore the function and specific mechanism of circRFX3 in glioma.

Methods: RT-qPCR or western blot was applied to examine the expression of RNAs or proteins. Functional assays were carried out to evaluate the influence of circRFX3, RFX3 and PROX1 on glioma cells. In vivo experiments were done to ascertain the impact of circRFX3 on glioma growth. Moreover, mechanism assays were conducted to investigate the molecular relation among circRFX3, RFX3, HNRNPK and PROX1.

Results: CircRFX3 was highly expressed in glioma cells. CircRFX3 knockdown led to the suppression of glioma cell and tumor growth. CircRFX3 overexpression resulted in the opposite outcomes. Mechanism analyses suggested that circRFX3 recruited HNRNPK to enhance RFX3 mRNA stability, thereby facilitating glioma cell malignant behaviors. RFX3 was also unveiled to affect glioma cells via stimulating PROX1 transcription.

Conclusion: CircRFX3, as a tumor promoter, could recruit HNRNPK to stabilize RFX3 mRNA in glioma cells. Additionally, RFX3 could promote PROX1 transcription to promote glioma progression.

Keywords: Glioma; HNRNPK; PROX1; RFX3; circRFX3.

MeSH terms

  • Carcinogenesis / genetics
  • Carcinogenesis / metabolism
  • Cell Line, Tumor
  • Cell Proliferation / genetics
  • Disease Progression
  • Gene Expression Regulation, Neoplastic / genetics
  • Glioma* / genetics
  • Glioma* / metabolism
  • Heterogeneous-Nuclear Ribonucleoprotein K* / genetics
  • Heterogeneous-Nuclear Ribonucleoprotein K* / metabolism
  • Homeodomain Proteins* / genetics
  • Homeodomain Proteins* / metabolism
  • Humans
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • RNA, Circular* / genetics
  • RNA, Circular* / metabolism
  • Regulatory Factor X Transcription Factors* / genetics
  • Regulatory Factor X Transcription Factors* / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Tumor Suppressor Proteins* / genetics
  • Tumor Suppressor Proteins* / metabolism
  • Up-Regulation / genetics

Substances

  • Heterogeneous-Nuclear Ribonucleoprotein K
  • Homeodomain Proteins
  • MicroRNAs
  • RFX3 protein, human
  • RNA, Circular
  • Regulatory Factor X Transcription Factors
  • Transcription Factors
  • Tumor Suppressor Proteins
  • prospero-related homeobox 1 protein
  • HNRNPK protein, human