Western blotting to determine Bid and t-Bid levels in Caco-2 cells (Top) and HT29 cells (Bottom).

<p>Caco-2 and HT29 cells were treated with MA at IC₅₀ and IC₈₀ concentrations for 4 h. The levels of protein expression are expressed as arbitrary intensity units of each band compared to arbitrary intensity units of actin. MA produced clear effects on this protein in Caco-2 cells. However, this effect was not observable in HT29 cells. The values represent means ± SD. of at least three independent experiments performed in triplicate. Key: <i>(*) p<0</i>.<i>05</i> and <i>(**) p<0</i>.<i>01</i>, with respect to the untreated cells.</p

Schematic representation of the different mechanisms proposed for the induction of apoptosis by MA in colon-cancer Caco-2 cells (right) and HT29 cells (left).

<p>MA is able to activate both intrinsic and extrinsic apoptotic mechanisms according to the type of cell involved. <i>Abbreviations</i>: Cps, caspase; cit c, cytochrome-c.</p

Top: western blotting of the levels of pro-caspase-9 and caspase-9; centre: pro-caspase-8 and caspase-8; and bottom: pro-caspase-3 and caspase-3 proteins.

<p>Caco-2 cells were treated with MA at IC₅₀ and IC₈₀ concentrations for 4 h. The levels of protein expression are expressed as arbitrary intensity units of each band compared to arbitrary intensity units of actin. The values represent means ± S.D. of at least three independent experiments performed in triplicate. Key: <i>(*) p<0</i>.<i>05</i>, <i>(**) p<0</i>.<i>01</i> and <i>(***) p<0</i>.<i>001</i>, with respect to the untreated control cells.</p