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. Author manuscript; available in PMC: 2013 Feb 1.
Published in final edited form as: Anticancer Agents Med Chem. 2012 Feb;12(2):151–162. doi: 10.2174/187152012799015002

Table 2.

Combination Index (C.I.) values for lapatinib + MK-8669 (1:10)

Cell line ED50 ED75 ED90 Dm m r
MDA361 1581.46933 3.8312e-012 0.04294 0.01883 −0.043822 0.99312
JIMT 0.01445 0.00286 0.00128 7.70049 −0.29234 0.95796

Cells were treated with lapatinib (0.1, 1, or 10 μM), MK-8669 (1, 10, or 100 nM), or combination lapatinib plus MK-8669. After 6 days, proliferation was measured by MTS assay. The fraction of cells proliferating relative to solvent control-treated cells was determined, and C.I. values were determined for the combination using CalcuSyn software. C.I. values are listed for effective doses at which 50%, 75%, or 90% (ED50, ED75, and ED90, respectively) of cells were killed. Statistically, drug synergy is defined by C.I. values less than 1.0, and very strong synergy is defined by C.I. values less than 0.1. Dm, the median-effect (ED50) drug concentration; m < 1 indicates a negative sigmoidal shape to the dose-effect curve; r states the linear correlation coefficient.