Fig. 1

Mcl-1 expression correlates with improved adaptation of Her2-positive BC cell lines to hypoxia. a Improved adaptation to hypoxic conditions of Her2-positive versus Her2-negative BC cells and the benign MCF-10A cell line. BC cell lines were incubated under hypoxic conditions for the time periods indicated. Cell survival was analyzed by MTT assay. Data represent mean ± SD for triplicate samples. Results shown are representative of three independent experiments. b Significant protein levels of Mcl-1, but not Bcl-2 or Bcl-xL, in BC cells under hypoxic conditions. BC cell lines or the nonmalignant MCF-10A cells were incubated for 4 hours under hypoxic conditions and whole-cell extracts were analyzed by immunoblotting with indicated antibodies. Immunoblotting for Erk2 confirmed equal protein loading. c Upregulation of Mcl-1 in Her2-positive BC cells under hypoxic conditions. BC cell lines were incubated under hypoxic conditions for up to 24 hours. Whole-cell extracts were analyzed by immunoblotting with indicated antibodies. Immunoblotting for Erk2 confirmed equal protein loading. Densitometric measurements (NIH ImageJ software) [59] were used to quantitate Mcl-1 protein levels from western blot images normalized for Erk2. Densitometric data represent mean values ± SD. Data shown are representative of three independent experiments. C normoxic control, Erk2 extracellular signal-regulated kinase 2, Her2 human epidermal growth factor receptor 2, Hif hypoxia-inducible factor, Mcl-1 myeloid cell leukemia-1