Figure 5.

Chloroquine abolishes the glutamine-induced increase in mitochondrial mass in cocultured MCF7 cells, and augments apoptosis. (A) Fibroblasts were cocultured with MCF7 cells for 4 d in high glutamine media. Then, cells were treated either with 25 µM chloroquine (right) or vehicle alone (left) for 24 h. Cells were fixed and immunostained with antibodies against K8/18 (green) and the intact mitochondrial membrane (red). Nuclei were counter-stained with DAPI (blue). K8/18 specifically stains MCF7 cells (lower panels). The upper panels show the red channel only. Note that chloroquine treatment abolishes the glutamine-induced increase of mitochondrial mass of cocultured MCF7 cells. Original magnification, 40×. (B) MCF7 cells were cultured alone or in coculture with fibroblasts in the presence of chloroquine or vehicle alone (CTRL) under high glutamine conditions. Apoptosis was measured with PI staining. The percentage of apoptotic MCF7 cells (PI positive) is shown. Note that chloroquine does not induce apoptosis in MCF7 cells cultured alone, but does induce a 1.8-fold increase in apoptosis in MCF7 cells cocultured with fibroblasts.