αvβ1 integrin is enriched in extracellular vesicles of metastatic breast cancer cells: A mechanism mediated by galectin‐3

Abstract

Breast cancer cells release a large quantity of biocargo-bearing extracellular vesicles (EVs), which mediate intercellular communication within the tumour microenvironment and promote metastasis. To identify EV-bound proteins related to metastasis, we used mass spectrometry to profile EVs from highly and poorly metastatic breast cancer lines of human and mouse origins. Comparative mass spectrometry indicated that integrins, including αv and β1 subunits, are preferentially enriched in EVs of highly metastatic origin over those of poorly metastatic origin. These results are consistent with our histopathological findings, which show that integrin αv is associated with disease progression in breast cancer patients. Integrin αv colocalizes with the multivesicular-body marker CD63 at a higher frequency in the tumour and is enriched in circulating EVs of breast cancer patients at late stages when compared with circulating EVs from early-stage patients. With a magnetic bead-based flow cytometry assay, we confirmed that integrins αv and β1 are enriched in the CD63 + subsets of EVs from both human and mouse highly metastatic cells. By analysing the level of integrin αv on circulating EVs, this assay could predict the metastatic potential of a xenografted mouse model. To explore the export mechanism of integrins into EVs, we performed immunoprecipitation mass spectrometry and identified members of the galectin family as potential shuttlers of integrin αvβ1 into EVs. In particular, knockdown of galectin-3, but not galectin-1, causes a reduction in the levels of cell surface integrins β1 and αv, and decreases the colocalization of these integrins with CD63. Importantly, knockdown of galectin-3 leads to a decrease of integrin αvβ1This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Doxorubicin-Loaded Extracellular Vesicles Enhance Tumor Cell Death in Retinoblastoma

“…More specifically, in the context of cancer (and retinoblastoma), EVs play an important role in tumor progression as messengers in cellular interactions and homeostasis of the tumor microenvironment. For instance, studies have shown that cancer EVs with specific surface markers, such as integrins [ 64 , 65 ] or proteoglycans [ 66 , 67 ], can enhance the endocytic uptake of EVs within tumor cells. Hence, the unique characteristics of cancer EVs make them a promising drug delivery system because they could be loaded with chemotherapeutics (with increased endocytic delivery to tumors) and used as a novel cancer treatment; this remains unexplored to date in retinoblastoma.…”

“…In Y79 cells, we found that a substantially higher proportion of breast cancer EVs were endocytosed than non-cancerous ocular epithelial EVs. We propose that the accumulation of breast cancer EVs is related to the molecular composition of surface markers [ 64 , 65 ], which increases their capacity to become endocytosed compared to non-cancerous EVs. EV membrane proteins could include tetraspanins, integrins, or heparin sulfate proteoglycans; these may trigger increased cellular uptake by Y79 cells and mediate changes in signaling cascades [ 80 , 81 , 82 ].…”

The role and application of small extracellular vesicles in breast cancer

“…3) (88). This study highlights the potential of sEVs-bound integrin avb1 as a novel prognostic and therapeutic target in BC metastasis.…”

“…They demonstrated that integrin αv was detected more frequently in circulating sEVs of patients with late-stage (III and IV) than early-stage (I and II) BC. Further analysis revealed integrin αvβ1 is linked to sEVs from metastatic BC cells, whose export into sEVs is in part regulated byβ-Galactose lectin-3(Gal-3) ( 88 ). This study highlights the potential of sEVs-bound integrin αvβ1 as a novel prognostic and therapeutic target in BC metastasis.…”

Intercellular crosstalk between cancer cells and cancer-associated fibroblasts via extracellular vesicles

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