Fig. 4

Proliferation of breast cancer cells in response to astrocyte-secreted IL-1β. a Proliferation of human brain metastatic breast cancer cells in media collected from human astrocytes or human astrocytes exposed to MCC950. IL-1β neutralizing or control IgG antibodies were added to astrocyte-conditioned medium before application to breast cancer cells. Graphs represent the percentage of cells on the 4th day after plating, average ± SEM (N = 2 independent experiments, each performed in duplicate, 5 different fields of view photographed from each well). **P ≤ 0.01, ***P ≤ 0.001 compared to control (MDA-BrM2), ^###P ≤ 0.001 compared to “MDA-BrM2 + HA-CM” or “MDA-BrM2 + act. HA-CM”, ^$$$P ≤ 0.001 compared to “MDA-BrM2 + HA-CM” and “MDA-BrM2 + HA-CM + IgG” or “MDA-BrM2 + act. HA-CM” and “MDA-BrM2 + act. HA-CM + IgG” (ANOVA and Fisher’s LSD post hoc test). b Proliferation of mouse breast cancer cells in media collected from mouse astrocytes or mouse astrocytes exposed to MCC950. IL-1β neutralizing or control IgG antibodies were added to astrocyte-conditioned medium before application to breast cancer cells. Graphs represent the percentage of cells on the 4th day after plating, average ± SEM (N = 2 independent experiments, each performed in duplicate, 5 different fields of view photographed from each well). ***P ≤ 0.001, ****P ≤ 0.0001 compared to control (4T1-tdT), ^###P ≤ 0.001 compared to “4T1-tdT + MA-CM”, ^####P ≤ 0.0001 compared to “4T1-tdT + act. MA-CM”, ^$$$P ≤ 0.0001 compared to “4T1-tdT + MA-CM” and “4T1-tdT + MA-CM + IgG”, ^$$$$P ≤ 0.0001 compared to “4T1-tdT + act. MA-CM” and “4T1-tdT + act. MA-CM + IgG”, ^¤¤¤¤P ≤ 0.0001 compared to “4T1-tdT + MA-CM” (ANOVA and Fisher’s LSD post hoc test)