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

Figure 1

Rhythmic expression of the mammalian circadian protein period 2 (Per2) in nontumourigenic breast epithelial MCF-12A cells (a) and MDA-MB-231 estrogen receptor negative human breast adenocarcinoma cells (b). MCF-12A and MDA-MB-231 cells were harvested hourly for a period of 25 hours (Time 0 = baseline). Western blot analysis was employed to assess relative Per2 protein levels. Values (normalized to GAPDH) are expressed as a percentage of baseline and presented as mean ± SEM (). versus baseline.

(a)

(b)