Caspase-10 Is the Key Initiator Caspase Involved in Tributyltin-Mediated Apoptosis in Human Immune Cells

Figure 1

Induction of apoptosis in Jurkat T cells by TBT. Jurkat cells were treated with 1 μM TBT or ethanol (control) for 4 h before samples were analysed. Nuclei of vehicle-treated control cells (a) and after TBT treatment (b) were stained with Hoechst 33342 and analysed with a fluorescence microscope. Both pictures show an overlay of differential interference contrast light microscopy pictures with the fluorescence pictures. From the same experiment, samples were stained with annexin V-FITC for phosphatidylserine externalisation (c–h). Control cells were shown with DIC contrast (c), and no green fluorescence could be detected at 525 ± 12.5 nm (d). TBT-treated cells exhibit ruffled membranes and granular cytoplasm (e) and strong PS-labelling at the plasma membrane (f). The annexin-positive cells were further quantified by flow cytometry. The quadrant analysis of double labelled cells is shown for control (g) and TBT-treated cells (h). 10 000 cells of each sample were counted, and the percentage of viable cells (lower left quadrant, grey dots), apoptotic cells (lower right, green dots), and necrotic cells (upper two quadrants, red dots) were given in the dot blots. On the left side of the figure, immunoblots for 8 different proteins were shown. Protein names and molecular weights are given aside the blots. Left lane: control sample; right lane: TBT-treated sample.