Roles of p63 in regulation of miRNA and LincRNA targets in metastatic cancer

描述（由申请人提供）：癌症的死亡率通常是由于远处转移的发展，几乎没有有效的全身治疗方法。因此，研究与体内转移调控相关的基因是非常重要的。p53家族成员p63的功能在p53功能已被确定的情况下开始被理解，包括细胞凋亡和肿瘤抑制（Su et al., Nature 2010）以及其他角色，如转移（Su et al., Nature 2010）、皮肤发育和干细胞维持（Su et al., cell stem cell 2009）。p63功能的复杂性部分是由于多个亚型的存在，而这些亚型以前无法独立研究。p63全长TA异构体包含一个在结构和功能上类似于p53的反活化结构域，而？p63的N异构体虽然也具有反式激活活性，但可以拮抗p53以及p63和p73 （p53家族的另一个成员）的TA异构体的活性。有趣的是，突变型p53存在于多种人类癌症中，已被证明与p63异构体相互作用并使其功能失活。通过培养和研究具有p63同种型特异性零等位基因的小鼠，TAp63-/-和？Np63-/-小鼠，我们已经证明这些基因在抑制肿瘤发生和转移中具有不同的作用。TAp63-/-小鼠对自发转移性肿瘤非常敏感，并且TAp63通过直接协调Dicer和几种miRNAs的转录调控有效抑制肿瘤转移（Su et al., Nature 2010）。此外，我们将这些发现扩展到多种人类肿瘤类型，包括鳞状细胞癌、肺腺癌和乳腺腺癌，表明TAp63的这种功能非常重要。我们也证明了？Np63可以抑制入侵并转录调节DGCR8， DGCR8是miRNA加工所必需的另一种至关重要的酶。我们假设TAp63和？Np63调节不同细胞区室中不同的mirna，抑制肿瘤发生和转移，并参与DNA损伤反应。我们将通过提出以下具体目标来解决我们的假设：具体目标1：了解肿瘤起源细胞（表皮细胞）中p63亚型对miRNA和LincRNA靶点的调控机制。特异性目的2：了解p63亚型在皮肤癌和转移干细胞中对miRNAs和LincRNAs的调控机制。特异性目的3：了解p63亚型调控的miRNAs和LincRNAs在DNA损伤反应和p53补偿中的作用。

DESCRIPTION (provided by applicant): Mortality in cancer is most often due to the development of distant metastases for which almost no effective systemic treatments exist. The study of genes relevant for the regulation of metastasis in vivo is therefore of great importance. The functions of p63, a p53 family member, are beginning to be understood in contexts in which p53 function has been well established, including apoptosis and tumor suppression (Su et al., Nature 2010) as well as in other roles such as metastasis (Su et al., Nature 2010), skin development, and stem cell maintenance (Su et al., Cell Stem Cell 2009). The complexity of p63 function is due in part to the existence of multiple isoforms that previously could not be studied independently. Full length TA isoforms of p63 contain a transactivation domain, structurally and functionally resembling p53, whereas the ?N isoforms of p63, while also possessing transactivation activity, antagonize the activities of p53 and the TA isoforms of p63 and p73, the other p53 family member. Interestingly, mutant p53, present in a wide variety of human cancers, has been shown to interact with p63 isoforms and inactivate their function. By generating and studying mice with isoform-specific null alleles of p63, the TAp63-/- and ?Np63-/- mice, we have shown that these genes have distinct roles in suppression of tumorigenesis and metastasis. TAp63-/- mice are highly susceptible to spontaneous metastatic tumors, and TAp63 potently suppresses tumor metastasis by direct coordinate transcriptional regulation of Dicer and several miRNAs (Su et al., Nature 2010). In addition, we have extended these findings to multiple human tumor types including squamous cell carcinoma, lung adenocarcinoma, and breast adenocarcinoma, indicating this function of TAp63 is widely important. We have also shown that ?Np63 can suppress invasion and transcriptionally regulates DGCR8, another critically important enzyme necessary for miRNA processing. We hypothesize that TAp63 and ?Np63 regulate distinct miRNAs in different cellular compartments to suppress tumorigenesis and metastasis and to engage the DNA damage response. We will address our hypothesis by proposing the following specific aims: Specific Aim 1: To understand the mechanistic regulation of miRNA and LincRNA targets by p63 isoforms in the cell of origin of carcinomas (epidermal cells). Specific Aim 2: To understand the mechanistic regulation of miRNAs and LincRNAs by p63 isoforms in stem cells of skin cancer and metastasis. Specific Aim 3: To understand the roles of miRNAs and LincRNAs regulated by p63 isoforms in the DNA damage response and p53 compensation.