Renal cell carcinoma escapes death by p53 depletion through transglutaminase 2-chaperoned autophagy

Cell Death Dis. 2016 Mar 31;7(3):e2163. doi: 10.1038/cddis.2016.14.

Abstract

In renal cell carcinoma, transglutaminase 2 (TGase 2) crosslinks p53 in autophagosomes, resulting in p53 depletion and the tumor's evasion of apoptosis. Inhibition of TGase 2 stabilizes p53 and induces tumor cells to enter apoptosis. This study explored the mechanism of TGase 2-dependent p53 degradation. We found that TGase 2 competes with human double minute 2 homolog (HDM2) for binding to p53; promotes autophagy-dependent p53 degradation in renal cell carcinoma (RCC) cell lines under starvation; and binds to p53 and p62 simultaneously without ubiquitin-dependent recognition of p62. The bound complex does not have crosslinking activity. A binding assay using a series of deletion mutants of p62, p53 and TGase 2 revealed that the PB1 (Phox and Bem1p-1) domain of p62 (residues 85-110) directly interacts with the β-barrel domains of TGase 2 (residues 592-687), whereas the HDM2-binding domain (transactivation domain, residues 15-26) of p53 interacts with the N terminus of TGase 2 (residues 1-139). In addition to the increase in p53 stability due to TGase 2 inhibition, the administration of a DNA-damaging anti-cancer drug such as doxorubicin-induced apoptosis in RCC cell lines and synergistically reduced tumor volume in a xenograft model. Combination therapy with a TGase 2 inhibitor and a DNA-damaging agent may represent an effective therapeutic approach for treating RCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibiotics, Antineoplastic / pharmacology
  • Antibiotics, Antineoplastic / therapeutic use
  • Apoptosis* / drug effects
  • Autophagy / drug effects
  • Carcinoma, Renal Cell / drug therapy
  • Carcinoma, Renal Cell / metabolism
  • Carcinoma, Renal Cell / pathology
  • Cell Line, Tumor
  • Chloroquine / pharmacology
  • DNA Damage / drug effects
  • Doxorubicin / pharmacology
  • Doxorubicin / therapeutic use
  • Female
  • GTP-Binding Proteins / antagonists & inhibitors
  • GTP-Binding Proteins / genetics
  • GTP-Binding Proteins / metabolism*
  • Humans
  • Kidney Neoplasms / drug therapy
  • Kidney Neoplasms / metabolism
  • Kidney Neoplasms / pathology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Phosphorylation / drug effects
  • Protein Binding
  • Protein Glutamine gamma Glutamyltransferase 2
  • Proto-Oncogene Proteins c-mdm2 / antagonists & inhibitors
  • Proto-Oncogene Proteins c-mdm2 / genetics
  • Proto-Oncogene Proteins c-mdm2 / metabolism
  • Pyrazines / pharmacology
  • Pyrazines / therapeutic use
  • RNA-Binding Proteins / chemistry
  • RNA-Binding Proteins / metabolism
  • Transglutaminases / antagonists & inhibitors
  • Transglutaminases / genetics
  • Transglutaminases / metabolism*
  • Tumor Suppressor Protein p53 / chemistry
  • Tumor Suppressor Protein p53 / genetics*
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • 3-(phenylethynyl)-2-(2-(pyridin-2-yl)ethoxy)pyrido(3,2-b)pyrazine
  • Antibiotics, Antineoplastic
  • P62 protein, human
  • Pyrazines
  • RNA-Binding Proteins
  • Tumor Suppressor Protein p53
  • Doxorubicin
  • Chloroquine
  • Protein Glutamine gamma Glutamyltransferase 2
  • Transglutaminases
  • MDM2 protein, human
  • Proto-Oncogene Proteins c-mdm2
  • GTP-Binding Proteins