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Figure 1 | Cancer Cell International

Figure 1

From: Upstream molecular signaling pathways of p27 (Kip1) expression in human breast cancer cells in vitro: differential effects of 4-hydroxytamoxifen and deficiency of either D-(+)-glucose or L-leucine

Figure 1

4-Hydroxytamoxifen - but not tamoxifen - up-regulated the expression of p27 in estrogen receptor (ER) and LKB1-double negative human MDA-MB-231 breast cancer cells in vitro. (a) Schematic drawing of the luciferase reporter plasmids containing the following proximal 5'-upstream regions of the p27 gene, namely -1797 p27 (p27-Kpn I), -774 p27 (p27-Apa I), and -575 p27 (p27-5'UTR). (b) Tamoxifen did not up-regulate the relative luciferase activity of p27-Kpn 1, Apa I or 5'UTR in MDA-MB-231 cells (c) 4-Hydroxytamoxifen up-regulated the relative luciferase activity of the three p27- luciferase reporter plasmids in MDA-MB-231 cells. In all experiments, the cells were exposed to either DMSO or 1 μM each of tamoxifen or 4-hydroxytamoxifen for 24 hours. All assays were performed in triplicates and repeated three times. (d) Schematic diagram showing how 4-hydroxytamoxifen could up-regulate the expression of p27, arrest the progression of cell cycle from G1 to S phase, and inhibit DNA replication.

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Cancer Cell International

ISSN: 1475-2867

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