Constitutive activation of the DNA damage response pathway as a novel therapeutic target in diffuse large B-cell lymphoma

Oncotarget. 2015 Mar 30;6(9):6553-69. doi: 10.18632/oncotarget.2720.


The recent finding that MYC-driven cancers are sensitive to inhibition of the DNA damage response (DDR) pathway, prompted us to investigate the role of DDR pathway as therapeutic target in diffuse large B-cell lymphoma (DLBCL), which frequently overexpresses the MYC oncogene. In a preliminary immunohistochemical study conducted on 99 consecutive DLBCL patients, we found that about half of DLBCLs showed constitutive expression of the phosphorylated forms of checkpoint kinases (CHK) and CDC25c, markers of DDR activation, and of phosphorylated histone H2AX (γH2AX), marker of DNA damage and genomic instability. Constitutive γH2AX expression correlated with c-MYC levels and DDR activation, and defined a subset of tumors characterised by poor outcome. Next, we used the CHK inhibitor PF-0477736 as a tool to investigate whether the inhibition of the DDR pathway might represent a novel therapeutic approach in DLBCL. Submicromolar concentrations of PF-0477736 hindered proliferation in DLBCL cell lines with activated DDR pathway. These results were fully recapitulated with a different CHK inhibitor (AZD-7762). Inhibition of checkpoint kinases induced rapid DNA damage accumulation and apoptosis in DLBCL cell lines and primary cells. These data suggest that pharmacologic inhibition of DDR through targeting of CHK kinases may represent a novel therapeutic strategy in DLBCL.

Keywords: CHK1; CHK2; MYC; diffuse large B-cell lymphoma; gamma-H2AX; genomic instability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Benzodiazepinones / pharmacology*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Checkpoint Kinase 1
  • Checkpoint Kinase 2 / antagonists & inhibitors*
  • Checkpoint Kinase 2 / metabolism
  • DNA Damage*
  • Dose-Response Relationship, Drug
  • Histones / metabolism
  • Humans
  • Lymphoma, Large B-Cell, Diffuse / drug therapy*
  • Lymphoma, Large B-Cell, Diffuse / genetics
  • Lymphoma, Large B-Cell, Diffuse / metabolism
  • Lymphoma, Large B-Cell, Diffuse / pathology
  • Molecular Targeted Therapy
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology*
  • Protein Kinases / metabolism*
  • Proto-Oncogene Proteins c-myc / metabolism
  • Pyrazoles / pharmacology*
  • Thiophenes / pharmacology*
  • Time Factors
  • Tumor Cells, Cultured
  • Urea / analogs & derivatives*
  • Urea / pharmacology
  • cdc25 Phosphatases / metabolism


  • 3-(carbamoylamino)-5-(3-fluorophenyl)-N-(3-piperidyl)thiophene-2-carboxamide
  • Antineoplastic Agents
  • Benzodiazepinones
  • H2AX protein, human
  • Histones
  • MYC protein, human
  • PF 00477736
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins c-myc
  • Pyrazoles
  • Thiophenes
  • Urea
  • Protein Kinases
  • Checkpoint Kinase 2
  • CHEK1 protein, human
  • CHEK2 protein, human
  • Checkpoint Kinase 1
  • CDC25C protein, human
  • cdc25 Phosphatases