Flow Cytometric FRET Analysis of erbB Receptor Interaction on a Cell-by-Cell Basis

摘要

Lateral interaction of c-erbB family receptors resulting in dimer formation is the key event initiatingsignal transduction. Consequently cross-activation and intracellular signaling is triggered withimmediate impact on cell proliferation, migration, cell survival, and differentiation. In order toelucidate the connection of signal input (receptor activation) and signal output (altered cellularbehavior) we dynamically assessed cell proliferation of BT474 and SK-BR-3 breast cancer celllines. We quantitated c-erbB2 receptor homodimerization upon treatment with the therapeuticmonoclonal anti-c-erbB2 antibodies trastuzumab (Herceptin) and pertuzumab by flow cytometricFRET (FCET) measurements on a cell-by-cell basis and calculated the extent of antibody-inducedcell cycle exit. The results confirm that trastuzumab does not decrease c-erbB2 homodimersdespite its strong potency to drive c-erbB2-overexpressing cells into quiescence. Pertuzumab,however, is able to prevent c-erbB2 homodimerization and thereby enhance the antiproliferativeeffect of trastuzumab when administered in combination.