Detection and downregulation of type i IGF receptor expression by antibody-conjugated quantum dots in breast cancer cells

Hua Zhang, Deepali Sachdev, Chun Wang, Allison Hubel, Martine Gaillard-Kelly, Douglas Yee

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


The type I insulin-like growth factor (IGF) receptor (IGF1R) is a transmembrane tyrosine kinase involved in breast cancer proliferation, survival, and metastasis. Several monoclonal antibodies directed against the receptor are in clinical trials. In order to develop a methodology to detect and measure IGF1R levels in breast cancer cells, we covalently conjugated an IGF1R antibody, AVE-1642, with quantum dots (Qdots), which are nanocrystals that emit fluorescence upon excitation. AVE-1642 Qdots only bound to cells that express IGF1R, and measured IGF1R levels by fluorescence emission at 655 nm. After binding to the cell surface, AVE-1642 Qdots underwent receptor mediated endocytosis, localized to endosome, and later translocated into the nucleus. Treating MCF-7 cells with AVE-1642 Qdots, but not unconjugated Qdots alone, downregulated IGF1R levels and rendered cells refractory to IGF-I stimulation. Furthermore, cell proliferation was slightly inhibited by AVE-1642 Qdots, but not the unconjugated Qdots. Our data suggest that AVE-1642 Qdots can be used to detect IGF1R expression and measure changes in cell surface receptor levels. In addition, the inhibitory effect of AVE-1642 Qdots to cell proliferation implies that it may serve as a traceable therapeutic agent.

Original languageEnglish (US)
Pages (from-to)277-285
Number of pages9
JournalBreast Cancer Research and Treatment
Issue number2
StatePublished - Mar 2009

Bibliographical note

Funding Information:
Acknowledgments We thank Dr. Renato Baserga for R-cells. We are grateful to the services from the University of Minnesota Cancer Center Flow Cytometry Shared Resource and Confocal Microscopy Facility.Grant support: Department of Defense Post-doctoral Grant BC050548 (HZ) and R01CA74285 (DY), and Cancer Center Support Grant P30 077598.


  • Antibody
  • Breast cancer
  • Quantitative measurement
  • Quantum dots
  • Type I IGF receptor


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