The centrosomal protein Tax1 binding protein 2 is a novel tumor suppressor in hepatocellular carcinoma regulated by cyclin-dependent kinase 2

Hepatology. 2012 Nov;56(5):1770-81. doi: 10.1002/hep.25851. Epub 2012 Sep 17.


Deregulation of cellular-signaling pathways by the inactivation of tumor-suppressor genes is one of the major causes of hepatocellular carcinoma (HCC). In this study, we identified Tax1 binding protein 2 (TAX1BP2) as a novel tumor-suppressor gene in HCC. TAX1BP2 transcript was frequently underexpressed (42.2% with T/NT <0.5; P < 0.03) in HCCs, and underexpression of TAX1BP2 was associated with poorer overall survival rates in patients after surgical resection. An effector domain (ED) for TAX1BP2 tumor-suppressor activity was mapped to the amino-acid residues 267-756. Transient or stable expression of either full-length or ED of TAX1BP2 significantly suppressed HCC cell tumorigenicity through the activation of the p38/p53/p21 pathway. In contrast, silencing of TAX1BP2 by short interfering RNA remarkably suppressed the activation of the p38/p53/p21 pathway. Finally, phosphorylation of TAX1BP2 at serine-763 by cyclin-dependent kinase (CDK)2 abolished the TAX1BP2-mediated p38 activation and tumor-suppressive activity, indicating that TAX1BP2 can adapt CDK2 signaling to the p38/p53/p21 pathway.

Conclusion: Taken together, our data provide the first evidence that TAX1BP2 is a CDK2-regulated tumor-suppressor gene in HCC and is a novel activator of the p38/p53/p21 pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Hepatocellular / genetics*
  • Carcinoma, Hepatocellular / metabolism
  • Carcinoma, Hepatocellular / pathology
  • Centrosome / metabolism
  • Cyclin-Dependent Kinase 2 / metabolism*
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism
  • Down-Regulation
  • Gene Expression Regulation, Neoplastic*
  • Gene Silencing
  • Hep G2 Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Kaplan-Meier Estimate
  • Liver Neoplasms / genetics*
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology
  • MAP Kinase Signaling System / genetics
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism*
  • Phosphorylation
  • Tumor Suppressor Protein p53 / metabolism


  • Cyclin-Dependent Kinase Inhibitor p21
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Tumor Suppressor Protein p53
  • VAC14 protein, human
  • Cyclin-Dependent Kinase 2