TABLE 2

Quantitative efficacy FIC analyses of the interactive responses between CBD and DNA-damaging agents on cell viability 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).

CellCBDTMZBCNUCDDP
IC50 ValueFIC IndexIC50 ValueFIC IndexIC50 ValueFIC Index
Human cell lines
 T98G1.00E-069.19E-04 ± 7.50E-050.76 ± 0.052.81E-04 ± 8.78E-051.10 ± 0.304.34E-05 ± 1.84E-055.73 ± 2.36
3.00E-066.83E-04 ± 1.55E-040.90 ± 0.101.94E-04 ± 1.08E-041.09 ± 0.373.92E-05 ± 2.12E-055.48 ± 2.73
 U2511.00E-067.78E-04 ± 8.00E-051.86 ± 0.181.66E-04 ± 4.25E-051.26 ± 0.294.42E-05 ± 2.22E-054.24 ± 2.08
3.00E-068.99E-04 ± 8.54E-072.34 ± 0.002.40E-04 ± 2.75E-051.99 ± 0.195.99E-05 ± 7.51E-065.93 ± 0.70
 U87MG1.00E-069.17E-04 ± 1.79E-041.16 ± 0.195.86E-04 ± 8.58E-051.34 ± 0.172.48E-04 ± 5.15E-053.76 ± 0.74
3.00E-061.52E-03 ± 1.16E-032.19 ± 1.225.01E-04 ± 1.46E-041.57 ± 0.291.75E-04 ± 9.19E-063.11 ± 0.13
Mouse primary cells
 PDGF-GBM1.00E-065.43E-04 ± 9.26E-0510.78 ± 1.80*1.78E-05 ± 7.04E-072.14 ± 0.072.05E-06 ± 3.97E-072.72 ± 0.48
3.00E-061.20E-04 ± 6.86E-053.06 ± 1.331.47E-05 ± 4.44E-062.29 ± 0.473.14E-06 ± 5.68E-074.53 ± 0.69
 NPCs1.00E-061.24E-04 ± 4.55E-053.07 ± 1.013.29E-05 ± 1.81E-053.58 ± 1.798.32E-07 ± 1.56E-071.72 ± 0.26
3.00E-064.99E-05 ± 4.84E-052.05 ± 1.088.71E-06 ± 4.49E-061.80 ± 0.456.00E-07 ± 2.74E-071.95 ± 0.46
  • When DNA-damaging agents were combined with CBD at 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 viability 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. 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).

  • * P < 0.05, mouse PDGF-GBM cells versus mouse NPCs.