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. Author manuscript; available in PMC: 2009 Oct 1.
Published in final edited form as: Cancer Res. 2008 Oct 1;68(19):7985–7994. doi: 10.1158/0008-5472.CAN-08-1418

Figure 3.

Figure 3

Figure 3

Acquired resistance to paclitaxel is mediated by BCL-2 protein family members. A, EC50 values of parental (MCF-7 and MDA-MB-468) and paclitaxel-resistant cell lines (MCF-7 TaxR30, MCF-7 TaxR50 and MDA-MB-468 TaxR, respectively) were evaluated with MTT assay after treatment with various doses of paclitaxel for 48 h. EC50 values were determined by nonlinear regression analysis using GraphPad Prism software. Bars, SE. B and C, Western blot analysis of BCL-2 protein family members in parental and paclitaxel-resistant cell lines. Paclitaxel-resistant cell lines marked with “+” were grown in continuous exposure to paclitaxel (30 nM for MCF-7 TaxR30, 50 nM for MCF-7 TaxR50, 15 nM for MDA-MB-468 TaxR) or paclitaxel was withdrawn from growth media for 24 hours to reduce the possibility of acute paclitaxel-mediated variations in protein levels (marked with “-”). Total cellular proteins were isolated either in the presence or in the absence of paclitaxel in growth media and analyzed in parallel. β-Actin was probed as a loading control.