Distinct mechanisms of microRNA sorting into cancer cell-derived extracellular vesicle subtypes

Abstract
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Abstract

Extracellular vesicles (EVs) encompass a variety of vesicles secreted into the extracellular space. EVs have been implicated in promoting tumor metastasis, but the molecular composition of tumor-derived EV sub-types and the mechanisms by which molecules are sorted into EVs remain mostly unknown. We report the separation of two small EV sub-populations from a metastatic breast cancer cell line, with biochemical features consistent with different sub-cellular origins. These EV sub-types use different mechanisms of miRNA sorting (selective and non-selective), suggesting that sorting occurs via fundamentally distinct processes, possibly dependent on EV origin. Using biochemical and genetic tools, we identified the Lupus La protein as mediating sorting of selectively packaged miRNAs. We found that two motifs embedded in miR-122 are responsible for high-affinity binding to Lupus La and sorting into vesicles formed in a cell-free reaction. Thus, tumor cells can simultaneously deploy multiple EV species using distinct sorting mechanisms that may enable diverse functions in normal and cancer biology.

Data availability

RNA sequencing data have been deposited in SRA under accession code PRJNA532890.

The following data sets were generated

(2019) TGIRT-seq of extracellular vesicle sub populations released from MDA-MB-231 cells
SRA, PRJNA532890.

https://www.ncbi.nlm.nih.gov/sra/PRJNA532890

Article and author information

Author details

Morayma M Temoche-Diaz

Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, United States

Competing interests
No competing interests declared.

"This ORCID iD identifies the author of this article:" 0000-0003-1119-1749
Matthew J Shurtleff

Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States

Competing interests
No competing interests declared.

"This ORCID iD identifies the author of this article:" 0000-0001-9846-3051
Ryan M Nottingham

Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, United States

Competing interests
No competing interests declared.

"This ORCID iD identifies the author of this article:" 0000-0001-6937-5394
Jun Yao

Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, United States

Competing interests
No competing interests declared.
Raj P Fadadu

Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States

Competing interests
No competing interests declared.
Alan M Lambowitz

Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, United States

Competing interests
Alan M Lambowitz, Thermostable group II intron reverse transcriptase (TGIRT) enzymes and methods for their use are the subject of patents and patent applications that have been licensed by the University of Texas and East Tennessee State University to InGex, LLC. A.M.L., some former and present members of the A.M.L. laboratory, and the University of Texas are minority equity holders in InGex, LLC and receive royalty payments from the sale of TGIRT enzymes and kits and from the sublicensing of intellectual property to other companies..
Randy Schekman

Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States

For correspondence
schekman@berkeley.edu

Competing interests
Randy Schekman, Reviewing Editor and Founding Editor-in-Chief, eLife.

"This ORCID iD identifies the author of this article:" 0000-0001-8615-6409

Funding

Howard Hughes Medical Institute

Randy Schekman

National Institutes of Health (R01 GM37949)

Alan M Lambowitz

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.