Estrogen receptor β participate in the regulation of metabolizm of extracellular matrix in estrogen α negative breast cancer

Abstract

The biology of breast cancer is closely releted to sex steroid hormones. Estrogen receptor β is overexpressed in around 70% breast cancer cases, referrd to as "ER positive". Estrogens bind to estrogen receptor and stimulate the transcription of genes involved in control of cell proliferation. Moreover, estrogens may induce growth factors and components of extracellular matrix and interact with them in a complex manner. Extracellular matrix and integrins play an important role in cell functions and their aberrant expressions are implicated in breast cancer development, invasion and metastasis. ER β is certainly associated with more differentiated tumors, while evidence of role of ER β is controversial. The highly invasive breast cancer ER β negative cell line MDA-MB 231 can be the model of exam the role of ER β in breast cancer. The aim of this study was to examine the role of activation of ER β on the metabolism of the extracellular matrix and the expression of β-1 integrin in the breast cancer cell line MDA-MB 231. The cells were exposed on the estradiol, tamoxifen, raloxifen and genisteina in dose dependent concentrations. To determine the relative rate of collagen syntesis we measured the time-dependent reduction of collagen-bound radioactivity after pulse-chase labeling with [3 H] prolina by Peterkofsky methods. The expression of β-1 integrin was determine by Western blot analysis. The activity of MMP2 and 9 were measured using gelatin zymography with an image analysis system. Our data suggest on the role of estrogen receptor β on the metabolism of extracellular matrix in the breast cancer line MDA - MB 231. Estradiol and SERMs regulate the expression of ECM proteins: collagen, integrins and enhance activity of metaloproteinases 2 and 9. © Polish Histochemical et Cytochemical Society.