It is known that estrogen (E2) and the hormonal status of the patient are important for the proliferation and treatment of breast cancer (CaM). As for the thyroid hormone (T3), although epidemiological studies are still contradictory about its influence on breast cancer, laboratory studies have demonstrated its ability to increase proliferation of cells with CaM E2 receptor (ER) positive, inducing expression of genes normally stimulated by E2 (PR, TGFa). Although T3 exert many actions by the classical genomic regulation of gene transcription, a number of effects of T3 occurs rapidly and are not affected by inhibitors of protein synthesis. Non-genomic actions of thyroid hormones are described in the plasma membrane, cytoplasm and cell organelles. In vitro, independent of protein synthesis, thyroxine (T4) induced inositol triphosphate (IP3) and calcium signaling by increasing the effects of interferon-g by PKC and PKA. Recently our group demonstrated that the gene Amphiregulin (AREG) was stimulated by E2 and T3 in MCF-7 cells. Thus, our hypothesis is that thyroid hormone alters the AREG gene expression without binding to nuclear receptors, via the activation of PI3K. We intend to elucidate the route of action of thyroid hormones in the activation of the amphiregulin gene in cell lines of breast adenocarcinoma. Methodology: The cell line of breast cancer MCF-7 will be tagged at intervals of 10 minutes, 30 minutes, 1 hour and 4 hours with T3 (10-8M), T3 (10-8M) + LY294002 (50¼M), LY294002 (50¼M) in the absence or presence of cycloheximide. It will be held extraction of total RNA to obtain cDNA - Reverse transcription (RT) of RNA and real-time PCR for the expression of AREG in each treatment.
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