Proteolytic matriptase-prostasin axis in breast cancer

描述(申请人提供)：Mattritase是一种细胞表面锚定的丝氨酸蛋白酶，最先在人类乳腺癌细胞系中发现，随后与乳腺癌病理的许多方面有关。Mattritase在人类乳腺癌细胞中表达上调，其表达增强已被证明与患者预后不良有关。目前，还不清楚Mattritase在乳腺癌的发生中起因果作用，还是在癌症生长和进展的次要事件中起主要作用，其作为治疗靶点的潜力仍未得到检验。到目前为止，对于功能丧失的小鼠的围产期致死性，还不能分析乳腺癌应用Matritase消融的效果；然而，我们的建议提出了绕过这一限制的新技术。在我们提出的研究中，将使用平行和互补的体外和体内“功能丧失”技术来描述Mattritase在乳腺癌中的作用的功能和机制特征。我们之前的研究已经确定GPI锚定的丝氨酸蛋白酶前列腺素是Matrigtase蛋白水解酶活性的生理底物和下游效应因子，我们将重点关注这个蛋白水解轴对乳腺癌生物学的潜在贡献。我们认为，这两种蛋白水解酶与肿瘤进展之间存在显著的相关性，因为我们已经证明，Mattritase和Prostasin在体内细胞与细胞的粘连中都起着关键作用，而这两种蛋白水平的变化都可以通过破坏上皮紧密连接的形成和完整性来扰乱这些粘连。 需要检验的假设是，Mattritase通过激活前列腺素酶原发挥关键作用，Mattritase/Prostasin蛋白分解途径对乳腺肿瘤的发生至关重要，特别是通过细胞-细胞黏附的丧失，从而促进体内的癌症发生。 为了检验这一假设，我们制定了两个具体目标。在第一个目标中，将使用Mattritase和Prostasin功能丧失的新型遗传小鼠模型来确定Mattritase/Prostasin蛋白水解轴在乳腺癌发生和发展中的意义。在第二个目标中，将研究前列腺素在乳腺癌细胞间黏附中的作用，重点是它在紧密连接、功能和完整性方面的作用。 将最先进的小鼠遗传学与基于2D和3D细胞培养的分析相结合，为研究人类癌症疾病提供了一种创新的策略，并可能为乳腺癌的诊断和治疗提供新的途径。

DESCRIPTION (provided by applicant): Matriptase is a cell-surface anchored serine protease that was first identified in human breast cancer cell lines and has subsequently been implicated in many aspects of breast cancer pathology. Matriptase is up-regulated in human breast carcinoma cancer cells, and its increased expression has been shown to correlate with poor patient outcome. Presently, it is unknown if matriptase plays a causal role in breast carcinogenesis or contributes primarily to secondary events of cancer growth and progression, and its potential as a therapeutic target remains untested. Perinatal lethality in matriptase loss-of-function mice has thus far precluded analysis of the effect of matriptase ablation in the mammary gland; however our proposal presents novel techniques to bypass this limitation. In our proposed study both functional and mechanistic characterization of matriptase's role in breast cancer will be performed using parallel and complimentary in vitro and in vivo "loss-of-function" techniques. Our previous research has identified the GPI-anchored serine protease prostastin as a physiological substrate and downstream effector of matriptase proteolytic activity, and we will focus on this proteolytic axis for its potential contribution to breast cance biology. We believe there to be a significant correlation between these two proteases and cancer progression, as we have demonstrated that both matriptase and prostasin play critical roles in cell to cell adhesions in vivo, and changes in levels of either protein can perturb these adhesions via disruption of epithelial tight junction formation and integrity. The hypothesis to be tested is that matriptase exerts critical functions through activation of the prostasin zymogen and that the matriptase/prostasin proteolytic pathway is critical for breast oncogenesis, specifically through the loss of cell-cell adhesions, and thereby the promotion of carcinogenesis in vivo. To test this hypothesis, we formulated two specific aims. In the first aim the significance of the matriptase/prostasin proteolytic axis in breast cancer initiation and progression will be determined using both matriptase and prostasin loss-of-function novel genetic mouse models. In the second aim the role of prostasin in cell-cell adhesion in breast cancer will be studied with emphasis on its role in tight junction function and integrity. The combination of state-of-the art mouse genetics with 2D and 3D cell culture based assays encompasses an innovative strategy for studying human cancerous disease, and may offer new avenues for diagnosis and therapy of breast cancer.