miR-200–containing extracellular vesicles promote breast cancer cell metastasis
Minh T.N. Le, … , Leonora Balaj, Judy Lieberman
Minh T.N. Le, … , Leonora Balaj, Judy Lieberman
Published December 1, 2014; First published November 17, 2014
Citation Information: J Clin Invest. 2014;124(12):5109-5128. https://doi.org/10.1172/JCI75695.
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Research Article

miR-200–containing extracellular vesicles promote breast cancer cell metastasis

Abstract

Metastasis is associated with poor prognosis in breast cancer patients. Not all cancer cells within a tumor are capable of metastasizing. The microRNA-200 (miR-200) family, which regulates the mesenchymal-to-epithelial transition, is enriched in the serum of patients with metastatic cancers. Ectopic expression of miR-200 can confer metastatic ability to poorly metastatic tumor cells in some settings. Here, we investigated whether metastatic capability could be transferred between metastatic and nonmetastatic cancer cells via extracellular vesicles. miR-200 was secreted in extracellular vesicles from metastatic murine and human breast cancer cell lines, and miR-200 levels were increased in sera of mice bearing metastatic tumors. In culture, murine and human metastatic breast cancer cell extracellular vesicles transferred miR-200 microRNAs to nonmetastatic cells, altering gene expression and promoting mesenchymal-to-epithelial transition. In murine cancer and human xenograft models, miR-200–expressing tumors and extracellular vesicles from these tumors promoted metastasis of otherwise weakly metastatic cells either nearby or at distant sites and conferred to these cells the ability to colonize distant tissues in a miR-200–dependent manner. Together, our results demonstrate that metastatic capability can be transferred by the uptake of extracellular vesicles.

Authors

Minh T.N. Le, Peter Hamar, Changying Guo, Emre Basar, Ricardo Perdigão-Henriques, Leonora Balaj, Judy Lieberman

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Figure 1

miR-200 microRNAs are secreted in EVs from 4T1E cells.

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miR-200 microRNAs are secreted in EVs from 4T1E cells. (A) Size distribu...
(A) Size distribution of EVs released by 4TO7 and 4T1E cells in 48-hour culture supernatants (3 experiments). (B) Immunoblot of proteins in 4T1E cells and their EVs (repeated twice). (C) Relative expression (log2) of miRNAs quantified by Firefly Cellular miRNA Assay and normalized using miR-16. Each value is an average of 4 independent experiments with values presented from low (green) to high (red). Undetected miRNAs (ND) are gray. (D) miR-200 copy number in 4T1E or 4TO7 EVs from cells, untreated or treated with RNase A and/or Triton X-100, quantified by TaqMan assay (3 experiments). (E) Representative images of lung sections, stained with H&E, from mice bearing 4TO7 or 4T1E mammary tumors (n = 6 mice). The number of mice with lung metastases is indicated below the images. Original magnification, ×10. (F) miRNA copy number in EVs in the circulation of tumor-free mice or mice bearing 4TO7 or 4T1E tumors. Blood was collected when primary tumors reached 15 mm in diameter. EVs were purified from the serum, and miRNAs were quantified by TaqMan assay (3 experiments). **P < 0.01, Student’s t test.