MiRNA Deregulation Distinguishes Anaplastic Thyroid Carcinoma (ATC) and Supports Upregulation of Oncogene Expression

SIMPLE SUMMARY: MicroRNAs are essential regulators of gene expression. Their deregulation is associated with a substantial reorganization of the transcriptome in anaplastic thyroid carcinoma (ATC). Here, we present an integrated, combinatorial approach based on miRNA–mRNA sequencing to unravel miRNA–mRNA networks deregulated in ATC. We identify miRNA–mRNA signatures sharply distinguishing ATC and uncover prime oncogenes upregulated by the downregulation of miRNAs in ATC. ABSTRACT: Anaplastic thyroid carcinoma (ATC) is the most fatal and rapidly evolving endocrine malignancy invading the head and neck region and accounts for up to 50% of thyroid cancer-associated deaths. Deregulation of the microRNA (miRNA) expression promotes thyroid carcinoma progression by modulating the reorganization of the ATC transcriptome. Here, we applied comparative miRNA–mRNA sequencing on a cohort of 28 thyroid carcinomas to unravel the association of deregulated miRNA and mRNA expression. This identified 85 miRNAs significantly deregulated in ATC. By establishing a new analysis pipeline, we unraveled 85 prime miRNA–mRNA interactions supporting the downregulation of candidate tumor suppressors and the upregulation of bona fide oncogenes such as survivin (BIRC5) in ATC. This miRNA-dependent reprogramming of the ATC transcriptome provided an mRNA signature comprising 65 genes sharply distinguishing ATC from other thyroid carcinomas. The validation of the deregulated protein expression in an independent thyroid carcinoma cohort demonstrates that miRNA-dependent oncogenes comprised in this signature, the transferrin receptor TFRC (CD71) and the E3-ubiquitin ligase DTL, are sharply upregulated in ATC. This upregulation is sufficient to distinguish ATC even from poorly differentiated thyroid carcinomas (PDTC). In sum, these findings provide new diagnostic tools and a robust resource to explore the key miRNA–mRNA regulation underlying the progression of thyroid carcinoma.