Antitumor activity of new pyrazolo[3,4-d]pyrimidine SRC kinase inhibitors in Burkitt lymphoma cell lines and its enhancement by WEE1 inhibition

Cell Cycle. 2012 Mar 1;11(5):1029-39. doi: 10.4161/cc.11.5.19519. Epub 2012 Mar 1.

Abstract

Burkitt lymphoma (BL) is a highly aggressive B cell neoplasm. Although intensive polychemotherapy regimens have proven very effective, they are associated with significant toxicities. Therefore, more rational therapies that selectively target the molecular abnormalities of BL are needed. Recent data suggest that the tyrosine kinase SRC could represent a therapeutic target for BL. We found that new pyrazolo[3,4-d]pyrimidine SRC inhibitors exerted a significant cytotoxic effect and induced apoptosis on two BL cell lines, as determined by MTS assays, cytofluorimetric analyses and caspase 3 assay. Notably, our SRC inhibitors proved to be more effective than the well-known SRC inhibitor PP2 [4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo[3,4-d]pyrimidine] in BL cells. Moreover, our small molecules induced a G 2/M arrest in BL cells through a possible new mechanism, whereby SRC inhibition hinders an AKT-WEE1-cyclin-dependent kinase 1 (CDK1) axis, leading to inhibition of CDK1, the main trigger of entry into mitosis. By using a small-molecule inhibitor of WEE1, a crucial CDK1 negative regulator, we were able to shift the balance toward apoptosis rather than growth arrest and enhance the efficacy of the SRC inhibitors, suggesting a possible use of these selective drugs in combination for a safe and efficient treatment of BL.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / toxicity*
  • Apoptosis / drug effects*
  • Burkitt Lymphoma / metabolism
  • Burkitt Lymphoma / pathology
  • CDC2 Protein Kinase / antagonists & inhibitors
  • CDC2 Protein Kinase / metabolism
  • Cell Cycle Proteins / antagonists & inhibitors
  • Cell Cycle Proteins / metabolism*
  • Cell Line, Tumor
  • G2 Phase Cell Cycle Checkpoints / drug effects
  • Humans
  • M Phase Cell Cycle Checkpoints / drug effects
  • Mitosis / drug effects
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / metabolism*
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Protein-Tyrosine Kinases / metabolism*
  • Pyrazoles / toxicity*
  • Pyrimidines / toxicity*
  • src-Family Kinases / antagonists & inhibitors*
  • src-Family Kinases / metabolism

Substances

  • AG 1879
  • Antineoplastic Agents
  • Cell Cycle Proteins
  • Nuclear Proteins
  • Pyrazoles
  • Pyrimidines
  • pyrazolo(3,4-d)pyrimidine
  • Protein-Tyrosine Kinases
  • WEE1 protein, human
  • src-Family Kinases
  • CDC2 Protein Kinase