Silencing of doublecortin-like (DCL) results in decreased mitochondrial activity and delayed neuroblastoma tumor growth

PLoS One. 2013 Sep 26;8(9):e75752. doi: 10.1371/journal.pone.0075752. eCollection 2013.

Abstract

Doublecortin-like (DCL) is a microtubule-binding protein crucial for neuroblastoma (NB) cell proliferation. We have investigated whether the anti-proliferative effect of DCL knockdown is linked to reduced mitochondrial activity. We found a delay in tumor development after DCL knockdown in vivo in doxycycline-inducible NB tumor xenografts. To understand the mechanisms underlying this tumor growth retardation we performed a series of in vitro experiments in NB cell lines. DCL colocalizes with mitochondria, interacts with the mitochondrial outer membrane protein OMP25/ SYNJ2BP and DCL knockdown results in decreased expression of genes involved in oxidative phosphorylation. Moreover, DCL knockdown decreases cytochrome c oxidase activity and ATP synthesis. We identified the C-terminal Serine/Proline-rich domain and the second microtubule-binding area as crucial DCL domains for the regulation of cytochrome c oxidase activity and ATP synthesis. Furthermore, DCL knockdown causes a significant reduction in the proliferation rate of NB cells under an energetic challenge induced by low glucose availability. Together with our previous studies, our results corroborate DCL as a key player in NB tumor growth in which DCL controls not only mitotic spindle formation and the stabilization of the microtubule cytoskeleton, but also regulates mitochondrial activity and energy availability, which makes DCL a promising molecular target for NB therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / genetics
  • Adenosine Triphosphate / metabolism
  • Animals
  • COS Cells
  • Cell Line
  • Cell Line, Tumor
  • Cell Proliferation
  • Chlorocebus aethiops
  • Down-Regulation / genetics
  • Electron Transport Complex IV / genetics
  • Electron Transport Complex IV / metabolism
  • Female
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Microtubule-Associated Proteins / genetics*
  • Microtubule-Associated Proteins / metabolism
  • Microtubules / genetics
  • Microtubules / metabolism
  • Mitochondria / genetics*
  • Mitochondria / metabolism
  • Mitochondria / pathology*
  • Neuroblastoma / genetics*
  • Neuroblastoma / metabolism
  • Neuroblastoma / pathology*
  • Neuropeptides / genetics*
  • Neuropeptides / metabolism
  • Phosphorylation / genetics
  • Spindle Apparatus / genetics
  • Spindle Apparatus / metabolism

Substances

  • Membrane Proteins
  • Microtubule-Associated Proteins
  • Neuropeptides
  • doublecortin protein
  • Adenosine Triphosphate
  • Electron Transport Complex IV

Grant support

This work was supported by the Foundation Villa Joep and Top Institute Pharma (TI Pharma). CPF was supported by the Netherlands Organization for Scientific Research (NWO), grant H64.09.016. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.