CELL CYCLE REGULATION IN NORMAL AND CANCER CELLS

描述（由申请人提供）：p27 Kip 1是一种进化上保守的蛋白质，通过与细胞周期蛋白和细胞周期蛋白依赖性激酶的抑制性相互作用调节细胞增殖，并通过与RhoA的抑制性相互作用调节细胞运动。从我们以前发表的研究和我们的初步结果，很明显，这两个功能在正常的细胞和生物体生理学中起着重要的作用，并且p27的失调可能是人类癌症中获得侵袭性恶性表型的重要步骤。该提案的具体工作将利用遗传学、生物化学和分子方法来解决与p27调控和功能相关的三个广泛问题。首先，我们将使用表达p27等位基因的“功能分离”的小鼠敲入模型来直接解决p27在发育过程中以及在成体细胞和组织中对细胞增殖和细胞运动的调节所起的具体作用。其次，我们将使用新技术来阐明在细胞周期的每个阶段调节p27蛋白丰度的不同生化机制。我们将利用这些见解来创建新的小鼠遗传模型，以解决正常细胞和组织中每个细胞周期特异性p27调控途径的重要性。第三，我们将研究p27在肿瘤细胞中的调节和功能。我们将使用分子方法和我们新的p27失调遗传模型来确定在不同肿瘤模型中引起核p27下调的机制。我们还将检验肿瘤中p27的失调导致细胞分裂和细胞运动之间失去正常协调的假设，从而导致侵袭性癌症的增殖和侵袭表型。

DESCRIPTION (provided by applicant): p27Kip1 is an evolutionarily conserved protein that regulates both cell proliferation, through inhibitory interactions with cyclins and cyclin-dependent kinases, and cell movement, through its inhibitory interaction with RhoA. From our previous published studies and from our preliminary results it is clear that both of these functions play an important role in normal cellular and organismal physiology and that misregulation of p27 can be an important step in the acquisition of an aggressive malignant phenotype in human cancers. The specific work of this proposal will utilize genetic, biochemical and molecular methods to address three broad issues related to p27 regulation and function. First, we will use mouse knock-in models expressing "separation of function" alleles of p27 to directly address what specific roles the regulation of cell proliferation and cell movement by p27 play during development and in adult cells and tissues. Second, we will use new technologies to elucidate the different biochemical mechanisms that regulate p27 protein abundance at each phase of the cell cycle. We will use these insights to create new mouse genetic models that will address the importance of each of the cell cycle-specific p27 regulatory pathways in normal cells and tissues. Third, we will study the regulation and function of p27 in tumor cells. We will determine the mechanisms that cause downregulation of nuclear p27 in different tumor models using both molecular methods and our new genetic models of p27 misregulation. We will also test the hypothesis that misregulation of p27 in tumors causes the loss of normal coordination between cell division and cell movement, thereby contributing to the proliferative and invasive phenotype of aggressive cancers.