TABLE 1

Quantitative efficacy FIC analyses of the interactive responses between CBD and DNA-damaging agents on cell proliferation of GBM cells and NPCs (method 2)

Data are expressed as means ± S.E.M. (n = 3 independent experiments, each in duplicate). CBD and IC50 values are given in molar concentrations (M).

CellCBD TMZBCNUCDDP
IC50 ValueFIC IndexIC50 ValueFIC IndexIC50 ValueFIC Index
Human cell lines
 T98G1.00E-063.71E-03 ± 2.14E-033.46 ± 1.884.42E-04 ± 4.19E-051.13 ± 0.093.99E-05 ± 2.02E-051.78 ± 0.80
3.00E-061.25E-03 ± 2.25E-041.69 ± 0.203.61E-04 ± 1.08E-041.35 ± 0.233.74E-05 ± 1.10E-052.08 ± 0.44
 U2511.00E-061.01E-03 ± 4.08E-071.17 ± 0.001.84E-04 ± 7.38E-051.01 ± 0.361.43E-05 ± 3.35E-062.23 ± 0.49
3.00E-061.07E-03 ± 4.08E-061.47 ± 0.001.93E-04 ± 4.85E-051.29 ± 0.242.39E-05 ± 5.07E-063.89 ± 0.75
 U87MG1.00E-065.73E-04 ± 1.53E-041.10 ± 0.254.65E-04 ± 1.38E-040.86 ± 0.212.19E-06 ± 4.26E-071.08 ± 0.18
3.00E-062.45E-04 ± 5.75E-050.86 ± 0.102.16E-04 ± 8.03E-050.78 ± 0.122.73E-06 ± 8.56E-071.62 ± 0.36
Mouse primary cells
 PDGF-GBM1.00E-066.66E-04 ± 1.85E-041.59 ± 0.357.78E-05 ± 3.14E-051.40 ± 0.714.88E-06 ± 1.82E-062.24 ± 0.72
3.00E-061.44E-04 ± 1.39E-051.23 ± 0.036.22E-05 ± 1.65E-052.25 ± 0.342.85E-06 ± 1.73E-062.08 ± 0.68
 NPCs1.00E-061.57E-03 ± 1.03E-030.66 ± 0.278.39E-05 ± 3.50E-052.78 ± 1.035.85E-06 ± 9.08E-072.17 ± 0.29
3.00E-061.09E-05 ± 5.39E-071.00 ± 0.005.43E-05 ± 5.33E-052.57 ± 1.561.98E-06 ± 1.01E-061.60 ± 0.32
  • When DNA-damaging agents were combined with CBD at a fixed concentration of 1 or 3 µM, IC50 values of the DNA-damaging agents and the efficacy FIC indices were calculated from the combinations producing half maximal inhibitory effects on inhibiting cell proliferation of human GBM cell lines, primary mouse PDGF-GBM cells, and NPCs. Synergy was defined as ΣFIC < 0.5, additivity was defined as 0.5 < ΣFIC < 4, and antagonism was defined as ΣFIC > 4. The vehicle comprised 0.05% dimethylsulfoxide (vehicle in lieu of CBD) plus 0.05% dimethylsulfoxide, ethanol, or PBS (vehicle in lieu of TMZ, BCNU, or CDDP, respectively).