Figure 1.

Overexpression of BAG3, HSP70 and other anti-apoptotic proteins and down-regulation of pro-apoptotic proteins in chemoresistant breast cancer cells.

(A) BT-549 and MDA-MB-468 parental and chemoresistant cell lines were treated with 3 μM of apoptotic cell death inducer staurosporine (STS) and DMSO (0.1%) as control for 6 hours followed by % of total cell death and % of Annexin-V positive & PI negative cells were estimated by flow cytometry. Data are representative of three independent experiments performed in triplicate. Columns represent means ± SEM. Statistical significance; *p<0.05, ** p<0.01, *** p<0.001 and ns not significant compared to controls (DMSO). (B) Western blot analysis shows anti-apoptotic proteins (Bcl-2, Bcl-xL, and Mcl-1) are over expressed and pro-apoptotic proteins (Bax and Bak) are down regulated in chemoresistant cell lines compared to the parental counterparts. (C) BAG3 and (D) HSP70 are highly expressed in various chemoresistant cell lines. GAPDH was used as loading control. Densitometric analysis of relative BAG3 protein expression was performed in BT-549 and MDA-MB-468 parental and chemoresistant cell lines. Columns represent means ± SEM. Statistical significance; ** p<0.01, *** p<0.001 compared to parental control cells.