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Figure 7 | Breast Cancer Research

Figure 7

From: Senescence evasion by MCF-7 human breast tumor-initiating cells

Figure 7

Senescence-related factors in MCF-7 monolayer and mammosphere populations. (a) Expression of key proteins involved in the cellular senescence pathway in response to increasing doses of ionizing radiation. Lysates were prepared from unirradiated cells and from cells harvested one hour after exposure to 1 or 10-Gy 60Co γ-radiation and analyzed by immunoblotting with antibodies against p21 and pRb. ppRb indicates phosphorylated pRb. Actin served as a loading control. (b) Senescence was measured in unirradiated (control) cells and irradiated (4 Gy, 3 days post-irradiation) MCF-7 monolayer and mammosphere cells by staining for β-galactosidase activity. Cells (n of more than 100) were counted independently by two individuals. The error bars represent the mean ± standard error of the mean. (c) Expression of ING1 protein. Lysates were prepared as described for Figure 6a. Western blots were performed with a mixture of four monoclonal antibodies against a domain common to ING1a, ING1b and ING1c. Based on the apparent molecular weight of the observed band (about 35 kDa), the protein was identified as ING1b.

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