BM mesenchymal stromal cell–derived exosomes facilitate multiple myeloma progression
Aldo M. Roccaro, … , David T. Scadden, Irene M. Ghobrial
Aldo M. Roccaro, … , David T. Scadden, Irene M. Ghobrial
Published March 1, 2013
Citation Information: J Clin Invest. 2013;123(4):1542-1555. https://doi.org/10.1172/JCI66517.
View: Text | PDF | Erratum
Research Article Oncology

BM mesenchymal stromal cell–derived exosomes facilitate multiple myeloma progression

Abstract

BM mesenchymal stromal cells (BM-MSCs) support multiple myeloma (MM) cell growth, but little is known about the putative mechanisms by which the BM microenvironment plays an oncogenic role in this disease. Cell-cell communication is mediated by exosomes. In this study, we showed that MM BM-MSCs release exosomes that are transferred to MM cells, thereby resulting in modulation of tumor growth in vivo. Exosomal microRNA (miR) content differed between MM and normal BM-MSCs, with a lower content of the tumor suppressor miR-15a. In addition, MM BM-MSC–derived exosomes had higher levels of oncogenic proteins, cytokines, and adhesion molecules compared with exosomes from the cells of origin. Importantly, whereas MM BM-MSC–derived exosomes promoted MM tumor growth, normal BM-MSC exosomes inhibited the growth of MM cells. In summary, these in vitro and in vivo studies demonstrated that exosome transfer from BM-MSCs to clonal plasma cells represents a previously undescribed and unique mechanism that highlights the contribution of BM-MSCs to MM disease progression.

Authors

Aldo M. Roccaro, Antonio Sacco, Patricia Maiso, Abdel Kareem Azab, Yu-Tzu Tai, Michaela Reagan, Feda Azab, Ludmila M. Flores, Federico Campigotto, Edie Weller, Kenneth C. Anderson, David T. Scadden, Irene M. Ghobrial

×

Figure 6

miR-15a expression differs between normal and MM BM-MSCs, and miR-15a–containing exosomes are transferred into MM cells.

Options: View larger image (or click on image) Download as PowerPoint
miR-15a expression differs between normal and MM BM-MSCs, and miR-15a–c...
(A) miR expression profiling on total RNA isolated from normal (n = 4), MM (n = 7), and MGUS (n = 2) BM-MSC–derived exosomes. A heatmap was generated after supervised hierarchical cluster analysis. Differential miR expression is shown by red (upregulation) versus blue (downregulation) intensity (d-Chip software; normal versus MM, 1.5-fold change, P < 0.05). (B) MM.1S and RPMI.8226 MM cells were cultured in the absence or presence of primary MM (n = 4) or normal (n = 3) BM-MSCs or the HS-5 cell line for 48 hours. miR-15a expression was determined by qRT-PCR in MM cells (2–ΔΔCt method, normalized to RNU6BmiR as reference). Results are average ± SD of 3 independent experiments. miR-15a was upregulated in MM cells when in contact with normal BM-MSCs. (C) Murine exosomes were isolated from BM of WT or miR-15a/16-1–/– mice and subsequently added to MM cells for 48 hours. miR-15a levels were determined by qRT-PCR in human MM cells (2–ΔΔCt method, normalized to C. elegansmiR-39 reference, used as spiked control). Bars represent SD. (D) MM cells were cultured in the presence or absence of murine WT or miR-15a/16-1–/– BM-MSCs for 48 hours, and cell proliferation was assessed as [3H]-thymidine uptake. Bars indicate SD. (E and F) HS-5 cells (E) or primary BM-MSCs (F) were transfected with scramble, pre–miR-15a, or anti–miR-15a probe. Cells were then exposed to the indicated exosomes for 48 hours. Cell-conditioned media absent cells and processed as in all samples tested served as control. Cell proliferation was assessed using [3H]-thymidine uptake assay. Bars indicate SD.