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Figure 6 | Breast Cancer Research

Figure 6

From: Estrogen and progesterone receptors have distinct roles in the establishment of the hyperplastic phenotype in PR-A transgenic mice

Figure 6

Matrix metalloproteinases in mammary glands of adult wild-type and PR-A transgenic mice analyzed by zymography. (a) Zymogram of protein extracts prepared from mammary glands of two PR-A mice, and a littermate control (WT). Graph shows comparison of the levels, estimated by laser densitometry, of total MMP-2 in transgenic mice (n = 5) and littermate control mice (n = 3). No statistically significant differences were found. Similar results were obtained for MMP-9 (data not shown). (b) Zymogram of protein extracts prepared from mammary glands of two PR null mutant mice (PR-/-), and a littermate control (WT). Graph shows comparison of the levels, estimated by laser densitometry, of total MMP-2 in PR-/- mice (n = 5) and littermate control mice (n = 4). There was a statistically significant reduction in the total levels of MMP-2 in the PR null mutant mice (P ≤ 0.01). (c) Representative zymograms showing activation of MMP-2 in wild-type mice only when they were treated with estrogen and progesterone. Representation of the mean ± standard error of the mean corresponding to the densitometric values of active MMP-2 in ovariectomized mice (Ovx, n = 6), ovariectomized mice treated with E (Ovx+E, n = 4), ovariectomized mice treated with P (Ovx+P, n = 3) and ovariectomized mice treated with estrogen and progesterone (Ovx+E+P, n = 3). In all cases, values were normalized to controls that were considered equal to 1. The increase in the levels of active MMP-2 were statistically significant in Ovx+E+P compared with Ovx (P ≤ 0.001), Ovx+E (P ≤ 0.05) and Ovx+P (**P ≤ 0.01). (d) Zymogram and densitometric analysis of mean ± standard error of the mean showing activation of MMP-2 by progesterone in ovariectomized PR-A mice (Ovx+P, n = 2) compared with ovariectomized mice (Ovx, n = 2). The increase in active MMP-2 activity was statistically significant (*P ≤ 0.05). AMMP, active matrix metalloproteinase; LMMP, latent matrix metalloproteinase; n, number of glands analyzed from different mice.

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