MicroRNA-182 drives metastasis of primary sarcomas by targeting multiple genes
Mohit Sachdeva, … , Diana M. Cardona, David G. Kirsch
Mohit Sachdeva, … , Diana M. Cardona, David G. Kirsch
Published September 2, 2014
Citation Information: J Clin Invest. 2014;124(10):4305-4319. https://doi.org/10.1172/JCI77116.
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Research Article

MicroRNA-182 drives metastasis of primary sarcomas by targeting multiple genes

Abstract

Metastasis causes most cancer deaths, but is incompletely understood. MicroRNAs can regulate metastasis, but it is not known whether a single miRNA can regulate metastasis in primary cancer models in vivo. We compared the expression of miRNAs in metastatic and nonmetastatic primary mouse sarcomas and found that microRNA-182 (miR-182) was markedly overexpressed in some tumors that metastasized to the lungs. By utilizing genetically engineered mice with either deletion of or overexpression of miR-182 in primary sarcomas, we discovered that deletion of miR-182 substantially decreased, while overexpression of miR-182 considerably increased, the rate of lung metastasis after amputation of the tumor-bearing limb. Additionally, deletion of miR-182 decreased circulating tumor cells (CTCs), while overexpression of miR-182 increased CTCs, suggesting that miR-182 regulates intravasation of cancer cells into the circulation. We identified 4 miR-182 targets that inhibit either the migration of tumor cells or the degradation of the extracellular matrix. Notably, restoration of any of these targets in isolation did not alter the metastatic potential of sarcoma cells injected orthotopically, but the simultaneous restoration of all 4 targets together substantially decreased the number of metastases. These results demonstrate that a single miRNA can regulate metastasis of primary tumors in vivo by coordinated regulation of multiple genes.

Authors

Mohit Sachdeva, Jeffrey K. Mito, Chang-Lung Lee, Minsi Zhang, Zhizhong Li, Rebecca D. Dodd, David Cason, Lixia Luo, Yan Ma, David Van Mater, Rebecca Gladdy, Dina C. Lev, Diana M. Cardona, David G. Kirsch

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Figure 1

miR-182 is elevated in a subset of metastatic sarcomas.

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miR-182 is elevated in a subset of metastatic sarcomas. (A) Schematic sh...
(A) Schematic showing amputation strategy used to study metastasis in KP mice. (B) Kaplan-Meier curve showing metastasis-free survival in KP mice. (C) Heat map showing differential expression of miRNAs between nonmetastatic and metastatic primary mouse sarcomas using miRNA TLDA array (blue color, low expression; red color, high expression; green color, nonmetastatic [nonmet]; black color, metastatic [met]). (D) Validation of elevated miR-182 expression in primary mouse STS measured by real-time RT-PCR. (E) ISH detects miR-182 expression in primary metastatic (M), but not in nonmetastatic (N) sarcomas from KP mice (blue, miR-182–digoxigenin probe (arrows); pink, Nuclear Fast Red). (F) Primary tumors from KPY mice were dissociated and then sorted for YFP-positive and -negative cells. RNA was then extracted from those cells, and miR-182 expression was analyzed using qRT-PCR. miR-182 expression was specific to YFP-expressing sarcoma cells, but not to YFP-negative cells. (G) Elevated miR-182 expression in primary human STS measured by real time RT-PCR. (H) Comparative genomic hybridization shows amplification of miR-182 locus, 6qA3.3, in primary mouse sarcomas with known metastatic outcome. Two-tailed Student’s t test was used for statistical analysis in D–G. All data are mean ± SEM. Scale bars: 100 μm (E and F); 25 μm (E, insets). *P < 0.05; **P < 0.01; ***P < 0.005.