Figure 5. Combination NDGA plus trastuzumab inhibits proliferation of trastuzumab-refractory breast cancer cells.

(A) SK-parental, (B) SK-HRp2, (C) BT-parental, and (D) BT-HRp3 cells were treated with NDGA (40 μM), trastuzumab (20 μg/mL), or a combination of both drugs for 6 d, at which point cell proliferation was measured by standard colorimetric MTS assay. Experiments were done at least twice, in 6 replicates per group each time. Cell proliferation is expressed as a percentage of untreated cells per line, with error bars representing standard deviation between replicates; values are shown above each bar. The combination of NDGA plus trastuzumab inhibited cell proliferation to a greater degree than either agent alone, suggesting that NDGA partially restores trastuzumab efficacy to trastuzumab-refractory breast cancer cells.


