Table 3. Combination indices (CI) for LY and AZD with SB216763. CI = (D)1/(Dx)1 + (D)2/(Dx)2 If CI < 1, =1, and >1 indicate synergism, additive effect, and antagonism, respectively.

Combination Index (CI)	MDA-MB 468	HCT 8
LY294002 + SB216763	1.139 ± 0.085	2.3 ± 0.3
AZD8055 + SB216763	2.113 ± 0.54	1.48 ± 0.21

The denominator, (Dx)1 and (Dx) 2 are the concentrations of each drug alone that inhibits cell growth by x%. The (D)1 and (D)2 values are the concentrations used in combination that inhibit cell growth by x%.