| Popis: |
Primary cultures of human mammary epithelial cells (HMEC) ex vivo underwent significant morphological and functional changes during the process of aging. Cells in S phase significantly declined after 19 d and accumulated in G0/G1 and G2/M phase after 50 d. Simultaneously, the initial estrogen receptor expression of 32,3% dropped to less than 1% in 19 d and 50 d aged HMEC, respectively. Estrogen treatment of HMEC demonstrated unaltered levels of P53 and phosphorylated P53 after 60 min. After 24 h of estrogen treatment, however, Western blot analysis revealed a significantly enhanced phosphorylation of P53 at Ser15 in 5 d and 19 d HMEC populations, respectively. A phospho-P53 ELISA confirmed a significant Ser15-phosphorylation of P53 in both HMEC populations following 24 h of estrogen stimulation, but no significant changes after 60 min, respectively. According to the estrogen receptor depletion in 19 d aged HMEC, these data indicated a receptor-independent estrogen signaling. |
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