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Figure 6 | BMC Cancer

Figure 6

From: Bcl-XL is qualitatively different from and ten times more effective than Bcl-2 when expressed in a breast cancer cell line

Figure 6

The functional activity of Bcl-XL in preventing doxorubicin induced apoptosis is about ten times greater than that of Bcl-2. Cell lines expressing A) Bcl-2, Bcl2-cb5 or Bcl2-acta and B) Bcl-XL, BclX-cb5, BclX-acta or BclX-Δt were treated with the specified dose of doxorubicin, and plotted against the apoptosis index (measured as in Figure 5). The data representing the dose response curves for vector transfected control cells (neo), Bcl-2 or Bcl-XL expressing cells shown in Figure 5 is duplicated here for comparison. The relative intensity recorded for actin blots prepared from the same samples are shown to the right and indicate that equivalent amounts of protein were analyzed for all samples. Bars indicate standard error of the mean, n ≥ 4. C) The EC50 values in μM doxorubicin for Bcl-2, Bcl-XL and mutants located at the ER (Bcl2-cb5, BclX-cb5), mitochondria (Bcl2-acta, BclX-acta) or cytoplasm (BclX-Δt) as determined from the graphs shown in A) and B). To correct for expression of the individual proteins these values were divided by the concentration of anti-apoptotic protein (expressed as nMol/mg total cell protein normalized to Bcl-2 #2) in each cell line. Grey bars – based on expression levels prior to drug treatment. Black bars – based on expression levels after drug treatment at the EC50.

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