Reciprocal interplay between thyroid hormone and microRNA-21 regulates hedgehog pathway–driven skin tumorigenesis
Daniela Di Girolamo, … , Domenico Salvatore, Monica Dentice
Daniela Di Girolamo, … , Domenico Salvatore, Monica Dentice
Published May 9, 2016
Citation Information: J Clin Invest. 2016;126(6):2308-2320. https://doi.org/10.1172/JCI84465.
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Research Article Oncology

Reciprocal interplay between thyroid hormone and microRNA-21 regulates hedgehog pathway–driven skin tumorigenesis

Abstract

The thyroid hormone–inactivating (TH-inactivating) enzyme type 3 iodothyronine deiodinase (D3) is an oncofetal protein that is rarely expressed in adult life but has been shown to be reactivated in the context of proliferation and neoplasms. D3 terminates TH action within the tumor microenvironment, thereby enhancing cancer cell proliferation. However, the pathological role of D3 and the contribution of TH metabolism in cancer have yet to be fully explored. Here, we describe a reciprocal regulation between TH action and the cancer-associated microRNA-21 (miR21) in basal cell carcinoma (BCC) skin tumors. We found that, besides being negatively regulated by TH at the transcriptional level, miR21 attenuates the TH signal by increasing D3 levels. The ability of miR21 to positively regulate D3 was mediated by the tumor suppressor gene GRHL3, a hitherto unrecognized D3 transcriptional inhibitor. Finally, in a BCC mouse model, keratinocyte-specific D3 depletion markedly reduced tumor growth. Together, our results establish TH action as a critical hub of multiple oncogenic pathways and provide functional and mechanistic evidence of the involvement of TH metabolism in BCC tumorigenesis. Moreover, our results identify a miR21/GRHL3/D3 axis that reduces TH in the tumor microenvironment and has potential to be targeted as a therapeutic approach to BCC.

Authors

Daniela Di Girolamo, Raffaele Ambrosio, Maria A. De Stefano, Giuseppina Mancino, Tommaso Porcelli, Cristina Luongo, Emery Di Cicco, Giulia Scalia, Luigi Del Vecchio, Annamaria Colao, Andrzej A. Dlugosz, Caterina Missero, Domenico Salvatore, Monica Dentice

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Figure 1

TH represses miR21 in mouse and human BCC.

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TH represses miR21 in mouse and human BCC. (A) Genome-wide miRNA express...
(A) Genome-wide miRNA expression analysis in D3-depleted and control BCC cells. All the deregulated miRNAs in shD3 relative to control cells are plotted against the P value. mmu-miR21, murine miR-21. (B) miR21 expression was measured by TaqMan real-time PCR in cDNAs from control BCC, shD3, and BCC cells treated with 30 nM T3 for 48 hours. (C) Schematic structural organization of the miR21 gene (red) and the miR21 enhancer region. The expression of the thyroid hormone–responsive element (TRE) and its comparison between species are indicated below. (D) ChIP analysis of the interaction between TRα and the miR21 enhancer region. Chromatin extracted from BCC cells was immunoprecipitated using the indicated antibodies. (E) miR21 expression was measured by TaqMan PCR in BCC cells carrying a mutated TRE element in the miR21 region (mutTRE) and control BCC cells (WT) treated or not with 30 nM T3 for 48 hours. Right: Reduction of miR21 in T3-treated cells versus nontreated cells in WT cells and CRISPR/Cas9–mediated TRE-mutated cells. *P < 0.05. Data represent the mean of at least 3 independent experiments in duplicate. SDs are indicated. Differences between samples were assessed by Student’s 2-tailed t test for independent samples.