Binding of Trastuzumab to ErbB2 Is Inhibited by a High Pericellular Density of Hyaluronan

Tímea Váradi, Tamás Mersich, Päivi Auvinen, Raija Tammi, Markku Tammi, Ferenc Salamon, István Besznyák, Ferenc Jakab, Zsolt Baranyai, János Szöllosi, Peter Nagy

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10 Citations (Scopus)

Abstract

Although trastuzumab is an efficient drug, primary and acquired resistance is a challenging problem. The authors have previously shown in mouse xenograft experiments that masking ErbB2 by hyaluronan leads to diminished binding of the antibody and consequent resistance. In the current work, they correlated trastuzumab binding with the pericellular density of hyaluronan in ErbB2-overexpressing human breast cancer samples. A method for quantifying the relative binding of trastuzumab was developed involving constant and low-frequency background subtraction, segmenting the image to membrane and background pixels followed by evaluation of trastuzumab fluorescence, normalized with the expression level of ErbB2, only in the membrane. The normalized binding of trastuzumab showed a negative correlation with the pericellular density of hyaluronan (r = -0.52) with the effect being the most pronounced in the extreme cases (i.e., low and high hyaluronan densities predicted strong and weak binding of trastuzumab, respectively). Removal of hyaluronan by hyaluronidase digestion unmasked the trastuzumab binding epitope of ErbB2 demonstrated by a significantly increased normalized binding of the antibody. The results show that the accumulation of pericellular hyaluronan plays a crucial role in masking ErbB2.

Original languageEnglish
Pages (from-to)567-575
Number of pages9
JournalJournal of Histochemistry and Cytochemistry
Volume60
Issue number8
DOIs
Publication statusPublished - Aug 1 2012

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Keywords

  • ErbB2
  • breast cancer
  • epitope masking
  • hyaluronan
  • trastuzumab resistance

ASJC Scopus subject areas

  • Anatomy
  • Histology

Cite this

Váradi, T., Mersich, T., Auvinen, P., Tammi, R., Tammi, M., Salamon, F., Besznyák, I., Jakab, F., Baranyai, Z., Szöllosi, J., & Nagy, P. (2012). Binding of Trastuzumab to ErbB2 Is Inhibited by a High Pericellular Density of Hyaluronan. Journal of Histochemistry and Cytochemistry, 60(8), 567-575. https://doi.org/10.1369/0022155412448070