Circadian Rhythms and Breast Cancer: The Role of Per2 in Doxorubicin-Induced Cell Death

Figure 4

Determining the effects of Per2 silencing on doxorubicin-induced cell death in the ER⁻ MDA-MB-231 breast cancer cells. MDA-MB-231 cells were subjected to (1) control conditions (C), (2) 2.5 μM doxorubicin (D), (3) 30 nM Per2 esiRNA (P), and (4) 30 nM Per2 for 48 hours + 2.5 μM doxorubicin for 24 hours (PD). (a) Representative western blots of Per2 protein expression in the MDA-MB-231 cancer cells following treatments. (b) Cell viability was assessed using the MTT assay. Values are expressed as a percentage of the control and presented as mean ± SEM (). versus control and versus doxorubicin. (c) Representative flow cytometry box plots of the MDA-MB-231 breast cancer cells obtained by Hoechst 33342 and propidium iodide (PI) staining following treatments. Q1 represents cells staining positive for Hoechst and negative for PI (live cells) and Q2 represents cells staining positive for both Hoechst and PI (dead cells).

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