Biological Function(s) of Maspin

描述（申请人提供）：乳腺癌是西方国家女性中最常见的恶性肿瘤。然而，尽管在开发乳腺癌转移潜力的有效预测因素方面做出了重大努力，但我们对参与维持正常乳腺上皮表型的基因的分子功能的理解仍然存在重大差距，其中许多基因在乳腺癌的发生和发展过程中发生了改变。这种竞争性更新应用程序推进了我们对maspin（乳腺丝状蛋白）的生物学功能及其与新发现的结合伙伴IRF6（干扰素调节因子6）的相互作用的认识，并重点描述了它们在正常乳腺腺泡发育过程中的独立和集体机制作用，以及它们在乳腺癌进展过程中的丧失，使用以下实验策略：利用功能失得实验策略，探讨maspin和IRF6在正常乳腺上皮细胞表型获得和维持以及乳腺癌细胞表型抑制中的关系。假设：Maspin和IRF6作为迁移、侵袭、肿瘤发生和/或转移的抑制因子在整体上起作用。具体目标2：利用三维培养模型，确定maspin/IRF6相互作用对正常乳腺上皮细胞沉积maspin蛋白到细胞外微环境的细胞和分子效应，以及暴露于maspin蛋白的乳腺癌细胞的潜在表型变化。假设：Maspin/IRF6相互作用导致正常乳腺上皮细胞分泌并沉积Maspin蛋白到微环境中，从而影响乳腺癌细胞表型和生物活性的表观遗传变化。特异性目标3：研究maspin和IRF6重新表达对乳腺癌细胞与其细胞外微环境相互作用的差异影响，特别关注基质金属蛋白酶将层粘连蛋白5 - γ - 2链切割成促迁移片段。假设：乳腺癌细胞中maspin和IRF6的重新表达减少了乳腺癌细胞产生层粘连蛋白5 - γ - 2和基质金属蛋白酶，导致其无法将层粘连蛋白5 - γ - 2链切割成促迁移片段。这些研究的翻译价值在于开发了在乳腺癌细胞中重新表达肿瘤抑制因子的新策略，从而在微环境中中和分化和促迁移信号。

DESCRIPTION (provided by applicant): Breast cancer is the most common malignancy among women in Western countries. However, despite significant efforts to develop valid predictors of breast cancer metastatic potential, there remains a critical gap in our understanding of the molecular function(s) of the genes involved in the maintenance of the normal mammary epithelial phenotype, many of which are altered during the onset and progression of breast cancer. This competitive renewal application advances our knowledge of the biological function(s) of maspin (mammary serpin) and its interactions with a newly identified binding partner IRF6 (Interferon Regulatory Factor 6) -- and focuses on characterizing their independent and collective mechanistic role(s) during normal mammary gland acini development and their loss during breast cancer progression, using the following experimental strategy: Specific Aim 1: Explore the relationship between maspin and IRF6 related to the acquisition and maintenance of the normal mammary epithelial cell phenotype and suppression of the breast cancer cell phenotype, using loss-and-gain-of-function experimental strategies. Hypothesis: Maspin and IRF6 work in an integral manner as suppressors of migration, invasion, tumorigenesis and/or metastasis. Specific Aim 2: Determine the cellular and molecular effects of maspin/IRF6 interactions on the deposition of maspin protein into the extracellular microenvironment by normal mammary epithelial cells, and on potential phenotypic changes in breast cancer cells exposed to it, using three-dimensional culture models. Hypothesis: Maspin/IRF6 interactions result in the secretion and deposition of maspin protein into the microenvironment by normal mammary epithelial cells which can influence an epigenetic change in the phenotype and biological activity of breast cancer cells. Specific Aim 3: Examine the differential effects of maspin and IRF6 re-expression on breast cancer cell interactions with their extracellular microenvironment, with particular focus on the cleavage of laminin 5 gamma2 chain by matrix metalloproteinases into promigratory fragments. Hypothesis: Re-expression of maspin and IRF6 in breast cancer cells diminishes the production of laminin 5 gamma2 and matrix metalloproteinases by breast cancer cells, resulting in their inability to cleave laminin 5 gamma2 chain into promigratory fragments. The translational value of these studies rests in the development of new strategies to re-express tumor suppressors in breast cancer cells that result in the neutralization of differentiation and promigratory signals in the microenvironment.