Selection of a MCF-7 Breast Cancer Cell Subpopulation with High Sensitivity to IL-1β: Characterization of and Correlation between Morphological and Molecular Changes Leading to Increased Invasiveness
Figure 2
MCF-7A3 cells show increased sensitivity to IL-1β demonstrated by their higher scattering, formation of colonies, and cell proliferation. Cells were seeded at very low density (200 cells per 100 mm dish) and allowed to grow until well-defined individual colonies were formed. Cells were then stimulated with IL-1β for 48 h. (A) Representative phase-contrast micrographs of colonies of MCF-7pl and MCF-7A3 cells show the difference in cell scattering under IL-1β stimulation. Arrowheads point to representative satellite colonies formed in MCF-7A3 cells after IL-1β stimulus. (B) Quantification of the colonies formed by the two subpopulations in nonstimulated and stimulated conditions. Data are expressed as mean ± SD of triplicated experiments. *; **. Comparisons were made between results from nonstimulated and IL-1β-stimulated conditions in the same cell subpopulation (Mann-Whitney U test). (C) Proliferation rate of MCF-7 and MCF-7A3 cells expressed as increase of calcein-AM fluorescence. Cultures of both cell types were stimulated with IL-1β as previously indicated. To determine proliferation rate, calcein-AM was added to cultures at 0, 24, 48, 72, and 96 h for 2 h. Calcein fluorescence emitted only by live cells was measured at 485 nm for excitation and 520 nm for emission. Values are presented as relative fluorescence related to time 0 h and it is the mean ± SD of three independent experiments.
