Anti-metastatic Effect of MCIP1 in Thyroid Cancer

描述（由申请人提供）：甲状腺癌是最常见的内分泌恶性肿瘤，其发病率是美国所有癌症中第二快速上升的。局部甲状腺癌的治疗是有效的，但远处转移或局部侵袭性肿瘤患者预后较差。尽管在确定甲状腺癌发展的致病机制方面取得了重大进展，但甲状腺癌进展的途径仍然不明确。因此，表征抑制甲状腺癌侵袭和转移的途径是开发针对这种疾病的靶向治疗的重要目标。GPR54已被鉴定为内源性产生的转移抑制肽，转移蛋白（KiSS-1基因产物）的受体。在过表达模型中，GPR54是一种g - α q-11偶联受体，激活磷脂酶C等途径，从而抑制转移。最近，GPR54基因失活突变的患者和GPR54缺失小鼠已被证明通过不确定的机制发生促性腺功能减退。在甲状腺癌中，我们已经证明GPR54在乳头状甲状腺癌中过表达，但在滤泡性甲状腺癌中缺失，滤泡性甲状腺癌是最容易发生远处转移的亚型。我们已经证明，除了激活PLC外，内源性表达的GPR54还激活甲状腺癌细胞中的E RKI/2，但不激活p38 MAPK。由于PLC、ERK和Akt的激活可诱导细胞增殖和迁移，我们推断GPR54还必须与其他途径相互作用才能发挥其抑制作用。为了鉴定可能与这些特性相关的gpr54改变基因，我们在转移汀刺激1和24小时后，对表达gpr54的甲状腺癌细胞分离的总RNA进行了cDNA阵列研究。在所有实验中（每个时间点重复RNA批次），在两个时间点，编码MCIP1（钙调磷酸酶抑制剂）的基因上调。这些数据已被定量RT-PCR证实，功能研究表明，转移汀下调甲状腺癌细胞中钙调磷酸酶的活性。本拨款申请的目的是确定钙调磷酸酶的抑制和MCIP1的上调是否参与转移汀的抗增殖和迁移作用，以及它们是否代表治疗这种侵袭性和经常致命的疾病的靶点。

DESCRIPTION (provided by applicant): Thyroid cancer is the most common endocrine malignancy and its incidence is the second fasting rising of all cancers in the United States. Therapy for localized thyroid cancer is effective, but patients with distant metastasis or locally aggressive tumors have a poor prognosis. Despite major advances in defining the pathogenic mechanisms for thyroid cancer development, the pathways responsible for thyroid cancer progression remain poorly defined. Thus, characterizing pathways that inhibit thyroid cancer invasion and metastasis represents an important goal for developing targeted therapies for this disease. GPR54 has been characterized to be the receptor for an endogenously produced metastasis inhibiting peptide, metastin (KiSS-1 gene product). In overexpression models, GPR54 is a G-alpha q-11-coupled receptor that activates phospholipase C and other pathways, resulting in metastasis inhibition. More recently, patients with inactivating mutations in the GPR54 gene and GPR54 null mice have been shown to develop hypogonadotropic hypogonadism through uncertain mechanisms. In thyroid cancer, we have demonstrated that GPR54 is overexpressed in papillary thyroid cancer, but is lost in follicular thyroid cancer, the subtype with the greatest predilection for distant metastasis. We have shown that, in addition to PLC activation, the endogenously expressed GPR54 aIso activates E RKI/2, but not p38 MAPK in thyroid cancer cells. Because PLC, ERK and Akt activation induce cell proliferation and migration, we reasoned that GPR54 must also interact with other pathways to exert its inhibitory effect. To identify GPR54-altered genes that might be related to these properties, we performed cDNA array studies on total RNA isolated from GPR54-expressing thyroid cancer cells after 1 and 24 hours of metastin stimulation. In all experiments (duplicate RNA batches for each time point), and at both time points, the gene encoding MCIP1 (calcineurin inhibitor) was upregulated. These data have been confirmed by quantitative RT-PCR and functional studies have demonstrated that metastin down-regulates calcineurin activity in thyroid cancer cells. The purpose of this grant application is to determine if inhibition of calcineurin and upregulation of MCIP1 are involved in the anti-proliferative and migratory effects of metastin, and if they represent targets for therapy of this aggressive and frequently fatal disease.