Automated electrorotation to reveal dielectric variations related to HER-2/neu overexpression in MCF-7 sublines.

PURPOSE: Electrorotation (ROT) is a technique that allows for determination of the dielectric properties of living cells when exposed to a rotating electric field. We evaluated the ROT behavior of MCF/neo and p185(neu) transfectancts MCF/HER2-11 and MCF/HER2-18 to investigate whether differences in HER-2/neu expression were associated with differences in dielectric properties in these cells. Experimental Design: P185(neu) was measured by Western blotting in MCF/neo cells and HER-2/neu transfectants MCF/HER2-11 and MCF/HER2-18. ROT spectra and cell membrane-specific capacitance were obtained for each cell line. RESULTS: The mean cell membrane-specific capacitance values for MCF/neo, MCF/HER2-11, and MCF/HER2-18 were 2.09, 1.70, and 2.56 microF/cm(2), respectively. The mean specific capacitance for MCF/neo was significantly different from that for MCF/HER2-11 (P = 0.006) and that for MCF/HER2-18 (P = 0.007). CONCLUSIONS: ROT is sufficiently sensitive to detect variations in dielectric properties in breast cancer cell lines overexpressing p185(neu). These differences may be related to the morphological alterations determined by HER-2/neu overexpression.