c-Jun NH2-terminal kinase activation is essential for DRAM-dependent induction of autophagy and apoptosis in 2-methoxyestradiol-treated Ewing sarcoma cells

Cancer Res. 2009 Sep 1;69(17):6924-31. doi: 10.1158/0008-5472.CAN-09-1270. Epub 2009 Aug 25.

Abstract

Ewing sarcoma and osteosarcoma are two aggressive cancers that affect bones and soft tissues in children and adolescents. Despite multimodal therapy, patients with metastatic sarcoma have a poor prognosis, emphasizing a need for more effective treatment. We have shown previously that 2-methoxyestradiol (2-ME), an antitumoral compound, induces apoptosis in Ewing sarcoma cells through c-Jun NH(2)-terminal kinase (JNK) activation. In the present study, we provide evidence that 2-ME elicits macroautophagy, a process that participates in apoptotic responses, in a JNK-dependent manner, in Ewing sarcoma and osteosarcoma cells. We also found that the enhanced activation of JNK by 2-ME is partially regulated by p53, highlighting the relationship of JNK and autophagy to p53 signaling pathway. Furthermore, we showed that 2-ME up-regulates damage-regulated autophagy modulator (DRAM), a p53 target gene, in Ewing sarcoma cells through a mechanism that involves JNK activation. The silencing of DRAM expression reduced both apoptosis and autophagy triggered by 2-ME in Ewing sarcoma and osteosarcoma cells. Our results therefore identify JNK as a novel mediator of DRAM regulation. These findings suggest that 2-ME or other anticancer therapies that increase DRAM expression or function could be used to effectively treat sarcoma patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Methoxyestradiol
  • Apoptosis / drug effects
  • Autophagy / drug effects
  • Bone Neoplasms / drug therapy
  • Bone Neoplasms / enzymology*
  • Bone Neoplasms / pathology
  • Cell Line, Tumor
  • Enzyme Activation / drug effects*
  • Estradiol / analogs & derivatives*
  • Estradiol / pharmacology
  • Humans
  • JNK Mitogen-Activated Protein Kinases / metabolism*
  • Membrane Proteins
  • Proteins / metabolism*
  • Sarcoma, Ewing / drug therapy
  • Sarcoma, Ewing / enzymology*
  • Sarcoma, Ewing / pathology
  • Signal Transduction / drug effects
  • Tubulin Modulators / pharmacology
  • Tumor Suppressor Protein p53 / metabolism
  • Up-Regulation

Substances

  • DRAM1 protein, human
  • Membrane Proteins
  • Proteins
  • Tubulin Modulators
  • Tumor Suppressor Protein p53
  • Estradiol
  • 2-Methoxyestradiol
  • JNK Mitogen-Activated Protein Kinases