A Novel Effect of β-Adrenergic Receptor on Mammary Branching Morphogenesis and its Possible Implications in Breast Cancer

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• 作者：Lucía Gargiulo ; María May…
• 关键词：Mammary gland development ; Beta ; adrenergic receptor ; Breast cancer ; Non ; tumorigenic breast epithelial cells ; Normal mammary gland ; Estrogen receptor
• 刊名：Journal of Mammary Gland Biology and Neoplasia
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：22
• 期：1
• 页码：43-57
• 全文大小：
• 刊物类别：Medicine
• 刊物主题：Oncology; Cancer Research;
• 出版者：Springer US
• ISSN：1573-7039
• 卷排序：22

文摘

Understanding the mechanisms that govern normal mammary gland development is crucial to the comprehension of breast cancer etiology. β-adrenergic receptors (β-AR) are targets of endogenous catecholamines such as epinephrine that have gained importance in the context of cancer biology. Differences in β₂-AR expression levels may be responsible for the effects of epinephrine on tumor vs non-tumorigenic breast cell lines, the latter expressing higher levels of β₂-AR. To study regulation of the breast cell phenotype by β₂-AR, we over-expressed β₂-AR in MCF-7 breast cancer cells and knocked-down the receptor in non-tumorigenic MCF-10A breast cells. In MCF-10A cells having knocked-down β₂-AR, epinephrine increased cell proliferation and migration, similar to the response by tumor cells. In contrast, in MCF-7 cells overexpressing the β₂-AR, epinephrine decreased cell proliferation and migration and increased adhesion, mimicking the response of the non-tumorigenic MCF-10A cells, thus underscoring that β₂-AR expression level is a key player in cell behavior. β-adrenergic stimulation with isoproterenol induced differentiation of breast cells growing in 3-dimension cell culture, and also the branching of murine mammary epithelium in vivo. Branching induced by isoproterenol was abolished in fulvestrant or tamoxifen-treated mice, demonstrating that the effect of β-adrenergic stimulation on branching is dependent on the estrogen receptor (ER). An ER-independent effect of isoproterenol on lumen architecture was nonetheless found. Isoproterenol significantly increased the expression of ERα, Ephrine-B1 and fibroblast growth factors in the mammary glands of mice, and in MCF-10A cells. In a poorly differentiated murine ductal carcinoma, isoproterenol also decreased tumor growth and induced tumor differentiation. This study highlights that catecholamines, through β-AR activation, seem to be involved in mammary gland development, inducing mature duct formation. Additionally, this differentiating effect could be resourceful in a breast tumor context.