Doublecortin-like kinase 1 promotes hepatocyte clonogenicity and oncogenic programming via non-canonical β-catenin-dependent mechanism

Sci Rep. 2020 Jun 29;10(1):10578. doi: 10.1038/s41598-020-67401-y.

Abstract

Chronic liver injury is a risk factor for cirrhosis and hepatocellular carcinoma (HCC). The molecular mechanisms that regulate the decision between normal injury repair and neoplastic initiation are unclear. Doublecortin-like kinase 1 (DCLK1), a tumor stem cell marker, is induced during cirrhosis and HCC. Here, we demonstrate that DCLK1-overexpressing primary human hepatocytes formed spheroids in suspension cultures. Spheroids derived from DCLK1-overexpressing hepatoma cells showed high level expression of active β-catenin, α-fetoprotein, and SOX9, suggesting that DCLK1 overexpression induces clonogenicity and dedifferentiated phenotypes in hepatoma cells. DCLK1 overexpression in hepatoma cells also increased phosphorylation of GSK-3β at Ser9. This was associated with an induction of a 48-kDa active β-catenin with a preserved hypophosphorylated N-terminus that interacted with nuclear TCF-4 resulting in luciferase reporter activity and cyclin D1 expression. DCLK1 downregulation inhibited 48-kDa β-catenin expression. The proteasome inhibitor bortezomib did not block the 48-kDa β-catenin, instead, caused a threefold accumulation, suggesting a proteasome-independent mechanism. Liver tissues from patients with cirrhosis and HCC revealed epithelial co-staining of DCLK1 and active β-catenin, and cleaved E-cadherin. Repopulated DCLK1-overexpressing primary human hepatocytes in humanized FRG mouse livers demonstrated active β-catenin. In conclusion, DCLK1 regulates oncogenic signaling and clonogenicity of hepatocytes by a novel non-canonical/atypical β-catenin-dependent mechanism.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Carcinogenesis
  • Carcinoma, Hepatocellular / genetics
  • Carcinoma, Hepatocellular / metabolism
  • Carcinoma, Hepatocellular / pathology
  • Cell Line, Tumor
  • Glycogen Synthase Kinase 3 beta / metabolism
  • Hep G2 Cells
  • Hepatocytes / cytology*
  • Hepatocytes / enzymology
  • Hepatocytes / metabolism*
  • Hepatocytes / pathology
  • Heterografts
  • Humans
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Liver Cirrhosis / pathology
  • Liver Neoplasms / genetics
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology
  • Mice
  • Mice, Inbred C57BL
  • Neoplastic Stem Cells / metabolism
  • Protein-Serine-Threonine Kinases / metabolism*
  • SOX9 Transcription Factor / metabolism
  • Spheroids, Cellular
  • alpha-Fetoproteins / metabolism
  • beta Catenin / metabolism*

Substances

  • AFP protein, human
  • CTNNB1 protein, human
  • Intracellular Signaling Peptides and Proteins
  • SOX9 Transcription Factor
  • SOX9 protein, human
  • alpha-Fetoproteins
  • beta Catenin
  • DCLK1 protein, human
  • Glycogen Synthase Kinase 3 beta
  • Protein-Serine-Threonine Kinases