Iliopoulos Dimitrios, Bimpaki Eirini I, Nesterova Maria, Stratakis Constantine A
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA.
Cancer Res. 2009 Apr 15;69(8):3278-82. doi: 10.1158/0008-5472.CAN-09-0155. Epub 2009 Apr 7.
MicroRNAs comprise a novel group of gene regulators implicated in the development of different types of cancer; however, their role in primary pigmented nodular adrenocortical disease (PPNAD) has not been investigated. PPNAD is a bilateral adrenal hyperplasia often associated with Carney complex, a multiple neoplasia syndrome; both disorders are caused by protein kinase A (PKA) regulatory subunit type 1A (PRKARIA)-inactivating mutations. We identified a 44-microRNA gene signature of PPNAD after comparing PPNAD with normal adrenal samples. Specifically, 33 microRNAs were up-regulated and 11 down-regulated in PPNAD relative to normal tissues. These results were validated by stem loop real-time PCR analysis. Comparison of microRNA microarray data with clinicopathologic variables revealed a negative correlation (r = -0.9499) between let-7b expression and cortisol levels in patients with PPNAD. Integration of microRNA microarray with serial analysis of gene expression data together with bioinformatic algorithm predictions revealed nine microRNA-gene target pairs with a potential role in adrenal pathogenesis. Using a PPNAD cell line, we showed that miR-449 was up-regulated and identified its direct target, WNT1-inducible signaling pathway protein 2 (WISP2); in addition, pharmacologic inhibition of PKA resulted in the up-regulation of miR-449 leading to the suppression of WISP2. Overall, we investigated, for the first time, the microRNA profile and its clinical significance in PPNAD; these data also suggest that PKA, via microRNA regulation, affects the Wnt signaling pathway, which through expression and clinical studies is suspected to be a primary mediator of PRKAR1A-related tumorigenesis.
微小RNA构成了一组新的基因调节因子，与不同类型癌症的发生发展有关；然而，它们在原发性色素沉着性结节性肾上腺皮质疾病（PPNAD）中的作用尚未得到研究。PPNAD是一种双侧肾上腺增生，常与卡尼综合征相关，后者是一种多肿瘤综合征；这两种疾病均由蛋白激酶A（PKA）调节亚基1A（PRKAR1A）失活突变引起。在将PPNAD与正常肾上腺样本进行比较后，我们确定了PPNAD的一个44个微小RNA的基因特征。具体而言，相对于正常组织，PPNAD中有33个微小RNA上调，11个下调。这些结果通过茎环实时PCR分析得到验证。微小RNA微阵列数据与临床病理变量的比较显示，PPNAD患者中let-7b表达与皮质醇水平之间呈负相关（r = -0.9499）。将微小RNA微阵列与基因表达数据的序列分析以及生物信息学算法预测相结合，揭示了9对在肾上腺发病机制中可能起作用的微小RNA-基因靶标对。使用PPNAD细胞系，我们发现miR-449上调并确定了其直接靶标，即WNT1诱导信号通路蛋白2（WISP2）；此外，PKA的药理抑制导致miR-449上调，从而抑制WISP2。总体而言，我们首次研究了PPNAD中的微小RNA谱及其临床意义；这些数据还表明，PKA通过微小RNA调节影响Wnt信号通路，通过表达和临床研究怀疑该通路是PRKAR1A相关肿瘤发生的主要介导因子。
