Synergistic Antiproliferative Effects of Combined γ-Tocotrienol and PPARγ Antagonist Treatment Are Mediated through PPARγ-Independent Mechanisms in Breast Cancer Cells
Figure 3
Isobologram analysis of treatment of γ-tocotrienol with PPARγ agonists and antagonists in +SA cells. Individual IC50 doses for γ-tocotrienol, (a) PPARγ agonists (rosiglitazone and troglitazone) and (b) PPARγ antagonists (GW9662 and T0070907) were calculated and then plotted on the -axes and -axes, respectively. The data point on the isobologram represents the actual doses of combined γ-tocotrienol and PPARγ agonists and antagonists. Combined treatment of γ-tocotrienol with PPARγ agonists rosiglitazone and troglitazone was found to be antagonistic, as evidenced by the location of the data point in the isobologram being well above the line defining additive effect. In contrast, the growth inhibitory effect of combined treatment of γ-tocotrienol with PPARγ antagonists GW9662 and T0070907 was found to be synergistic, as evidenced by the location of the data point in the isobologram being well below the line defining additive effect for both cell lines.
