NEIL3 promotes hepatoma epithelial-mesenchymal transition by activating the BRAF/MEK/ERK/TWIST signaling pathway

J Pathol. 2022 Dec;258(4):339-352. doi: 10.1002/path.6001. Epub 2022 Sep 30.


Hepatocellular carcinoma (HCC) is among the most prevalent visceral neoplasms. So far, reliable biomarkers for predicting HCC recurrence in patients undergoing surgery are far from adequate. In the aim of searching for genetic biomarkers involved in HCC development, we performed analyses of cDNA microarrays and found that the DNA repair gene NEIL3 was remarkably overexpressed in tumors. NEIL3 belongs to the Fpg/Nei protein superfamily, which contains DNA glycosylase activity required for the base excision repair for DNA lesions. Notably, the other Fpg/Nei family proteins NEIL1 and NEIL2, which have the same glycosylase activity as NEIL3, were not elevated in HCC; NEIL3 was specifically induced to participate in HCC development independently of its glycosylase activity. Using RNA-seq and invasion/migration assays, we found that NEIL3 elevated the expression of epithelial-mesenchymal transition (EMT) factors, including the E/N-cadherin switch and the transcription of MMP genes, and promoted the invasion, migration, and stemness phenotypes of HCC cells. Moreover, NEIL3 directly interacted with the key EMT player TWIST1 to enhance invasion and migration activities. In mouse orthotopic HCC studies, NEIL3 overexpression also caused a prominent E-cadherin decrease, tumor volume increase, and lung metastasis, indicating that NEIL3 led to EMT and tumor metastasis in mice. We further found that NEIL3 induced the transcription of MDR1 (ABCB1) and BRAF genes through the canonical E-box (CANNTG) promoter region, which the TWIST1 transcription factor recognizes and binds to, leading to the BRAF/MEK/ERK pathway-mediated cell proliferation as well as anti-cancer drug resistance, respectively. In the HCC cohort, the tumor NEIL3 level demonstrated a high positive correlation with disease-free and overall survival after surgery. In conclusion, NEIL3 activated the BRAF/MEK/ERK/TWIST pathway-mediated EMT and therapeutic resistances, leading to HCC progression. Targeted inhibition of NEIL3 in HCC individuals with NEIL3 induction is a promising therapeutic approach. © 2022 The Pathological Society of Great Britain and Ireland.

Keywords: BRAF; DNA repair; NEIL3; TWIST1; epithelial mesenchymal transition; hepatocellular carcinoma; invasion; migration.

MeSH terms

  • Animals
  • Carcinoma, Hepatocellular* / pathology
  • Cell Line, Tumor
  • Cell Movement
  • DNA Glycosylases* / genetics
  • Epithelial-Mesenchymal Transition / genetics
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Gene Expression Regulation, Neoplastic
  • Liver Neoplasms* / pathology
  • MAP Kinase Signaling System
  • Mice
  • Mitogen-Activated Protein Kinase Kinases / metabolism
  • Proto-Oncogene Proteins B-raf / genetics
  • Proto-Oncogene Proteins B-raf / metabolism
  • Signal Transduction
  • Twist Transcription Factors / metabolism


  • DNA Glycosylases
  • Mitogen-Activated Protein Kinase Kinases
  • Neil1 protein, mouse
  • Neil2 protein, mouse
  • Proto-Oncogene Proteins B-raf
  • NEIL3 protein, mouse
  • Extracellular Signal-Regulated MAP Kinases
  • Twist Transcription Factors