Carney Complex: A Model for PKA-Mediated Tumorigenesis

描述（由申请人提供）：Carney Complex （CNC）是一种遗传性综合征，由皮肤色素沉着、黏液瘤、色素神经鞘瘤和内分泌肿瘤组成。后者的例子包括肾上腺和垂体的分泌性肿瘤，以及甲状腺、睾丸、卵巢和乳房的非分泌性肿瘤。在由NIH K22职业发展奖资助的研究中，研究者发现PRKAR1A基因的失活突变导致了大约50%的受影响种类的疾病。该基因编码环状amp依赖性蛋白激酶（protein kinase A， PKA）的1A型调节亚基，PKA是许多内分泌和非内分泌细胞类型生长途径的关键调节因子。PKA也是大多数内分泌器官分泌细胞中调节激素释放的关键第二信使系统。这种调节亚基的缺失会导致PKA活性的失调，这在理论上会导致异常的细胞增殖和肿瘤发生。作为先前研究的一部分，研究者创造了携带Prkar1a基因条件或常规无效等位基因的转基因小鼠。在本提案中，我们将使用这些基因靶向小鼠来验证Prkarla完全缺失导致PKA信号失调，从而导致体外和体内细胞增殖异常的假设。体外研究将包括缺乏Prkarla基因的原代小鼠胚胎成纤维细胞（mef）的产生，以及对这些永生细胞的生物学分析。完整小鼠的研究将包括Prkarla杂合null小鼠的总体和分子表型，作为CNC的遗传模型，以及组织特异性null小鼠的表征。虽然CNC本身是一种罕见的综合征，但PKA在生长控制和其他细胞过程中的核心作用使这种人类疾病成为一种有吸引力的模型，用于了解PKA发挥其广泛的细胞内作用的手段，并有望了解PKA在细胞中的作用可能最终导致旨在治疗人类癌症的新疗法的发展。

DESCRIPTION (provided by applicant): Carney Complex (CNC) is an inherited syndrome comprised of spotty skin pigmentation, myxomas, pigmented schwannomas, and endocrine tumors. Examples of the latter include secretory tumors of the adrenal gland and pituitary, as well as non-secreting tumors of the thyroid, testes, ovaries, and breast. In research funded by an NIH K22 career development award, the investigator identified inactivating mutations in the PRKAR1A gene as responsible for the disease in approximately 50% of affected kindreds. This gene codes for the Type 1A regulatory subunit of the cyclic AMP-dependent protein kinase (Protein Kinase A, PKA), a key regulator of growth pathways in many endocrine and non-endocrine cell types. PKA is also a key second messenger system mediating hormone release in secretory cells from most endocrine organs. Loss of this regulatory subunit leads to dysregulation of PKA activity, which has been theorized to cause abnormal cell proliferation and tumorigenesis. As part of the prior research, the investigator created transgenic mice carrying a conditional or conventional null allele of the Prkar1a gene. In this proposal, we will use these gene-targeted mice to test the hypothesis that complete loss of Prkarla causes dysregulation of PKA signaling, leading to abnormal cell proliferation both in vitro and in vivo. The in vitro studies will comprise the generation of primary mouse embryonic fibroblasts (MEFs) that lack the Prkarla gene and an analysis of the biology of these immortalized cells. Studies in intact mice will include gross and molecular phenotyping of Prkarla heterozygous null mice as a genetic model for CNC, as well a characterization of tissue-specific null mice. Although CNC is itself a rare syndrome, PKA's central role in growth control and other cellular processes makes this human disease an attractive model for use in understanding the means by which PKA exerts its wide variety of intracellular effects, and holds the promise that understanding PKA's role in the cell may eventually lead to the development of new therapies aimed at treating human cancers.