Figure 4. α-tocopherol blocks the anti-proliferative and pro-apoptotic properties of other kinase inhibitors independently of its antioxidant capacities.

A Benzoyl-STS dose-response curves in presence or absence of 100 µM of α-tocopherol or 100 µM of trolox in a clone of HeLa cells stably expressing a C3/7-DAP. EC₅₀ values are shown below. B HeLa cells were treated with various concentrations of benzoyl-STS in presence or not of 100 µM of α-tocopherol or 100 µM of trolox, and stained for cell cycle profile. The percentage of cells in G2M is reported here. C, D HeLa cells were treated with increasing amount of flavopiridol (C) or roscovitine (D) with or without 100 µM of α-tocopherol for 24 hours. Cell cycle profile was determined by flow cytometry using propidium iodide staining and the ratio of the percentage of cells in G2M on the percentage of cells in G0G1 was calculated and reported. E S37614 dose-response curves in presence or absence of 100 µM of α-tocopherol, 100 µM of trolox or 3 mM of NAC were determined using a clone of HeLa cells stably expressing a C3/7-DAP. F DiI-stained HeLa cells were treated with increasing amounts of S37614 supplemented with vehicle or 100 µM of tocopherol, 100 µM of trolox or 3 mM of NAC. Cell proliferation dose response curves were established from the median intensity fluorescence of DiI obtained for each point and normalized to the untreated control cells. EC₅₀ values are shown in the table below the curves.