MicroRNA Signature of Primary Pigmented Nodular Adrenocortical Disease: Clinical Correlations and Regulation of Wnt Signaling

¹Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts and ²Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland

^* To whom correspondence should be addressed. E-mail: stratakc{at}mail.nih.gov.

	Abstract

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. [Cancer Res 2009;69(8):3278–82]

Key Words: Cushing's syndrome, adrenocortical tumors, primary pigmented adrenal hyperplasia, miR-449, WISP2

This article has been cited by other articles:

				X. Yang, M. Feng, X. Jiang, Z. Wu, Z. Li, M. Aau, and Q. Yu miR-449a and miR-449b are direct transcriptional targets of E2F1 and negatively regulate pRb-E2F1 activity through a feedback loop by targeting CDK6 and CDC25A Genes & Dev., October 15, 2009; 23(20): 2388 - 2393. [Abstract] [Full Text] [PDF]