Characterization of human non-metastatic MCF-7 and highly metastatic MDA-MB-231 breast carcinoma cells.
(A) Experimental metastatic potential. Numbers of lung nodules were counted after inoculation of the cells into the tail vein of nu/nu mice. (B) Biochemical analysis of mitochondrial respiratory complex activities. Respiratory complex I, complex II, complex III, and complex IV are components of the electron-transport chain and are located in the mitochondrial inner membrane. Mitochondrial respiratory function was examined by estimating the activities of the complexes. Because the activity of complexes II+III is comparable in MCF-7 and MDA-MB-231 cells, the reduced activity of complexes I+III in MDA-MB-231 cells must result from complex I defects. Bars represent the mean ± S.D. (n = 3). *P<0.05; **P<0.01. (C) Estimation of the amounts of ROS. Flow-cytometric analysis was carried out using 1×106 cells, which were treated with 5 µM DCFH-DA for quantitative estimation of ROS production.
