TABLE 1

EC50 for Trastuzumab, 111In-Trastuzumab, and 111In-NLS-Trastuzumab on Breast Cancer Cells with Different HER2 Expression and Trastuzumab-Resistance Status*

Antibody
Cancer cell lineTrastuzumab111In-Trastuzumab111In-NLS-Trastuzumab
MDA-MB-2318.3 ± 1.34.5 ± 0.65.4 ± 1.0
231-H2N3.2 ± 0.8†1.8 ± 0.5‡0.2 ± 0.02
TrR17.7 ± 1.31.2 ± 0.4§0.1 ± 0.03
TrR27.4 ± 1.23.4 ± 0.6‖3.2 ± 0.7‖

  • ↵* EC50 values are in μmol/L.

  • ↵† P < 0.05, compared with MDA-MB-231, TrR1, and TrR2.

  • ↵‡ P < 0.05, compared with MDA-MB-231.

  • ↵§ P < 0.05, compared with MDA-MB-231, TrR2, and trastuzumab.

  • ↵‖ P < 0.05, compared with trastuzumab.

  • ↵ P < 0.05, compared with MDA-MB-231, TrR2, trastuzumab, and 111In-trastuzumab.

  • Statistical comparisons between groups were made by Student t test. Results are expressed means ± SEM (n = 3–5).