Phosphoinsitide signaling in Breast Epithelial Morphogenesis and Metastasis

描述（由申请人提供）：根据美国癌症协会的报告，自1990年以来，美国乳腺癌死亡率每年下降约2%。这种令人印象深刻的连胜在很大程度上是由于早期发现和治疗的进步。大约90%的癌症死亡是由转移形成引起的。了解转移的潜在机制将为发现生物标志物提供线索，这对明确诊断和个性化治疗至关重要。极化上皮形态的建立和维持对正常乳腺结构的发育和肿瘤转移的抑制至关重要。细胞-细胞相互作用通常抑制细胞迁移和癌症转移，而细胞-基质粘附处的整合素信号是迁移和转移所必需的。我们的长期目标是了解控制上皮细胞形态发生的分子和机制，包括两个方面：上皮极性和细胞运动性。为了实现这一目标，我们一直专注于一种名为PIPKI3的关键脂质激酶，它通过调节E-钙粘蛋白介导的细胞间粘附组装或促进细胞基质粘附转换来调节上皮极性和细胞迁移。PIPKI3产生磷脂酰肌醇-4,5-二磷酸（pi4,5p2），通过调节肌动蛋白重组、细胞粘附组装和囊泡运输，是细胞形态发生的关键脂质第二信使。然而，它是如何调控的尚不清楚。我们观察到，当伤口愈合发生时，在上皮到迁移的转变过程中，PIPKI3从细胞-细胞粘附重新分布到细胞-基质粘附，这表明在转移的发展过程中，该激酶可能在相同的形态发生转变中发挥重要作用。在本研究中，我们将研究PIPKI3通过调控pi4,5p2的区域水平参与上皮形态发生和细胞迁移/转移的分子机制。使用一系列互补的方法，我们将定义PIPKI3如何调节e-钙粘蛋白向基底外膜的运输，细胞-细胞粘附的成熟，以及当细胞重新分布到细胞-基质粘附时促进细胞迁移。对PIPKI3的多种细胞作用的研究将有助于揭示乳腺上皮形态发生的复杂信号网络，并有助于理解上皮向迁移形态发生转化和肿瘤发生的机制。最终，我们希望将这些知识转化为新的策略，以便在PI4,5P2信号没有得到适当调节的细胞有机会发展为侵袭性转移性肿瘤之前检测它们。此外，这些研究将为新的生物标志物和癌症药物靶点提供强有力的候选物。这个项目的成果显然将有利于基础研究和临床病人护理。

DESCRIPTION (provided by applicant): Since 1990, the breast cancer death rate in the United States has decreased by ~2% per year, as reported by the American Cancer Society. This impressive winning streak was made possible in large part by advances in early detection and treatment. Approximately 90% of all cancer deaths arise from metastasis formation. Understanding the underlying mechanisms of metastasis will provide clues for biomarker discovery, which could be extremely important for definitive diagnosis and personalized treatment. Establishment and maintenance of the polarized epithelial morphology is essential for the development of normal breast structure and suppression of tumor metastasis. Cell-cell interactions generally inhibit cell migration and cancer metastasis, whereas integrin signals at cell-matrix adhesions are required for migration and metastasis. Our long-term goal is to understand the molecules and mechanisms that control the morphogenesis of epithelial cells including two aspects: epithelial polarity and cell motility. Towards this aim, we have been focusing on a critical lipid kinase, named PIPKI3, that regulates both epithelial polarity and cell migration via modulating E- cadherin mediated intercellular adhesion assembly or facilitating cell-matrix adhesion turnover. PIPKI3 generates phosphatidylinositol-4,5-bisphosphate (PI4,5P2), a critical lipid second messenger for cell morphogenesis by regulating actin reorganization, cell adhesion assembly, and vesicular trafficking. However, how it is regulated is not known. We observed that PIPKI3 was re-distributed from cell-cell adhesion to cell- matrix adhesion during the epithelial-to-migratory transition when wound healing occurs, indicating this kinase may have an important role in the same morphogenic transformation during the development of metastasis. In this proposal, we will investigate the molecular mechanisms by which PIPKI3 participates in epithelial morphogenesis and cell migration/metastasis via regulating the regional levels of PI4,5P2. Using a series of complementary approaches, we will define how PIPKI3 modulates the transport of E-cadherin to the basolateral membrane, maturation of cell-cell adhesion, and facilitates cell migration when re-distributed to the cell-matrix adhesions. Investigation of the diverse cellular roles of PIPKI3 will shed light on the complicated signaling networks that contribute to breast epithelial morphogenesis and will aid in the understanding of the mechanisms of the epithelial-to-migratory morphogenic transformation and tumorigenesis. Ultimately, we hope to translate this knowledge into new strategies for detecting cells where PI4,5P2 signaling is not appropriately regulated, before they have the opportunity to develop into aggressive metastatic tumors. Furthermore, these studies will provide potent candidates for new biomarkers and cancer drug targets. The outcomes of this project will clearly benefit both basic research and clinical patient care. PUBLIC HEALTH RELEVANCE: The loss of epithelial polarization and acquisition of migratory phenotype is essential for the development of cancer metastasis, the real lethal aspect of breast cancers. This proposal is designed to understand the molecular mechanism driving the initiation and the progression of this process. By exploring the role of phospholipid signaling in the progression of cancer metastasis, we should get valuable information toward understanding the signaling networks underlying metastasis, as well as define more potent targets for cancer therapies that aim to stop or reverse metastasis.