Selective cell death of oncogenic Akt-transduced brain cancer cells by etoposide through reactive oxygen species mediated damage

Mol Cancer Ther. 2007 Aug;6(8):2178-87. doi: 10.1158/1535-7163.MCT-07-0111.

Abstract

We have established several glioma-relevant oncogene-engineered cancer cells to reevaluate the oncogene-selective cytotoxicity of previously well-characterized anticancer drugs, such as etoposide, doxorubicin, staurosporine, and carmustine. Among several glioma-relevant oncogenes (activated epidermal growth factor receptor, Ras, and Akt, as well as Bcl-2 and p53DD used in the present study), the activated epidermal growth factor receptor, Ras, and Akt exerted oncogenic transformation of Ink4a/Arf(-/-) murine astrocyte cells. We identified that etoposide, a topoisomerase II inhibitor, caused selective killing of myristylated Akt (Akt-myr)-transduced Ink4a/Arf(-/-) astrocytes and U87MG cells in a dose- and time-dependent manner. Etoposide-selective cytotoxicity in the Akt-myr-transduced cells was shown to be caused by nonapoptotic cell death and occurred in a p53-independent manner. Etoposide caused severe reactive oxygen species (ROS) accumulation preferentially in the Akt-myr-transduced cells, and elevated ROS rendered these cells highly sensitive to cell death. The etoposide-selective cell death of Akt-myr-transduced cells was attenuated by pepstatin A, a lysosomal protease inhibitor. In the present study, we show that etoposide might possess a novel therapeutic activity for oncogenic Akt-transduced cancer cells to kill preferentially through ROS-mediated damage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Astrocytes / drug effects
  • Brain Neoplasms / pathology*
  • Cell Death / drug effects
  • Cell Transformation, Neoplastic / drug effects*
  • Cyclin-Dependent Kinase Inhibitor p16 / metabolism
  • Dose-Response Relationship, Drug
  • Etoposide / pharmacology*
  • Mice
  • Mice, Nude
  • Oncogene Protein v-akt / genetics
  • Oncogene Protein v-akt / metabolism*
  • Pepstatins / pharmacology
  • Reactive Oxygen Species / metabolism*
  • Time Factors
  • Transduction, Genetic*
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • Antineoplastic Agents
  • Cyclin-Dependent Kinase Inhibitor p16
  • Pepstatins
  • Reactive Oxygen Species
  • Tumor Suppressor Protein p53
  • Etoposide
  • Oncogene Protein v-akt
  • pepstatin