Identification of midkine as a mediator for intercellular transfer of drug resistance

Bernard L. Mirkin, Sandra Clark, Xin Zheng, Fei Chu, Bryan D. White, Marianne Greene, Abdelhadi Rebbaa*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


Resistance to cytotoxic agents is a major limitation for their clinical use to treat human cancers. Tumors become resistant to chemotherapy when a subset of cells undergoes molecular changes leading to overexpression of drug transport proteins, alterations in drug-target interactions or reduced ability to commit apoptosis. However, such changes may not be sufficient to explain why both resistant and nonresistant cells survive drug's action in tumors that ultimately become drug resistant. We hypothesized that, in such tumors, a cytoprotective relationship may exist between drug-resistant and neighboring drug-sensitive cells. The present study addresses the possibility that drug-resistant cells secrete in their culture medium factors able to protect sensitive cells from drug toxicity. A survival molecule, midkine, was identified by cDNA array to be expressed only in drug-resistant cells. Midkine-enriched fractions obtained by affinity chromatography exert a significant cytoprotective effect against doxorubicin in the wild-type drug-sensitive cells. Moreover, transfection of these cells with the midkine gene caused a decreased response to doxorubicin. The underlying mechanism of this cytoprotection appeared to imply activation of the Akt pathway and inhibition of drug-induced proliferation arrest as well as apoptotic cell death. These findings provide evidence for the existence of intercellular cytoprotective signals such as the one mediated by midkine, originating from cells with acquired drug resistance to protect neighboring drug-sensitive cells and thus contribute to development of resistance to chemotherapy.

Original languageEnglish (US)
Pages (from-to)4965-4974
Number of pages10
Issue number31
StatePublished - Jul 21 2005


  • Akt
  • Apoptosis
  • Drug resistance
  • Midkine
  • Senescence
  • p21/WAF1

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research


Dive into the research topics of 'Identification of midkine as a mediator for intercellular transfer of drug resistance'. Together they form a unique fingerprint.

Cite this