Total Blood Exosomes in Breast Cancer: Potential Role in Crucial Steps of Tumorigenesis

Abstract

Exosomes are crucial players in cell-to-cell communication and are involved in tumorigenesis. There are two fractions of blood circulating exosomes: free and cell-surface-associated. Here, we compared the effect of total blood exosomes (contain plasma exosomes and blood cell-surface-associated exosomes) and plasma exosomes from breast cancer patients (BCPs, n = 43) and healthy females (HFs, n = 35) on crucial steps of tumor progression. Exosomes were isolated by ultrafiltration, followed by ultracentrifugation, and characterized by cryo-electron microscopy (cryo-EM), nanoparticle tracking analysis, and flow cytometry. Cryo-EM revealed a wider spectrum of exosome morphology with lipid bilayers and vesicular internal structures in the HF total blood in comparison with plasma. No differences in the morphology of both exosomes fractions were detected in BCP blood. The plasma exosomes and total blood exosomes of BCPs had different expression levels of tumor-associated miR-92a and miR-25-3p, induced angiogenesis and epithelial-to-mesenchymal transition (EMT), and increased the number of migrating pseudo-normal breast cells and the total migration path length of cancer cells. The multidirectional effects of HF total blood exosomes on tumor dissemination were revealed; they suppress the angiogenesis and total migration path length of MCF10A, but stimulate EMT and increase the number of migrating MCF10A and the total path length of SKBR3 cells. In addition, HF plasma exosomes enhance the metastasis-promoting properties of SKBR3 cells and stimulate angiogenesis. Both cell-free and blood cell-surface-associated exosomes are involved in the crucial stages of carcinogenesis: the initiation of EMT and the stimulation of proliferation, cell migration, and angiogenesis. Thus, for the estimation of the diagnostic/prognostic significance of circulating exosomes in the blood of cancer patients more correctly, the total blood exosomes, which consist of plasma exosomes and blood cell-surface-associated exosomes should be used.

Secretion of Mutant DNA and mRNA by the Exosomes of Breast Cancer Cells

“…Most DNA was found inside the exosomes and did not degrade after treatment with DNase. some-transferred molecules to modulate the main properties of the recipient cells that are growth and survival, drug resistance was found to occur [1][2][3][4][5].…”

Clusterin and Its Potential Regulatory microRNAs as a Part of Secretome for the Diagnosis of Abnormally Invasive Placenta: Accreta, Increta, and Percreta Cases

“…Increased expression of miR-92a-3p contributes to the EMT and metastasis in colorectal cancer through activation of the Wnt/β-catenin pathway and inhibition of mitochondrial apoptosis [ 68 ] as well as in hepatocellular carcinoma and malignant retinoblastoma through the PTEN/Akt pathway [ 69 , 70 ]. Blood plasma exosomes from breast cancer patients and healthy donors were found to differ in the overexpression of miR-25-3p and miR-92a-3p, and this was related to the stimulation of the EMT of nonmalignant breast cells, significant increases in the number of motile and proliferating cells, as well as the formation of capillary-like structures [ 71 ].…”

Isolation of Cell-Free miRNA from Biological Fluids: Influencing Factors and Methods

“…References Membrane-coated microparticles Apoptotic bodies (0.1-5 µm) [15][16][17] Microvesicles (>0.5 µm) [17][18][19][20][21][22][23] Ectosomes (100-600 nm) [24] Oncosomes (1-10 µm) [17,25,26] Exosomes (30-150 nm) [17,18,22,24,[27][28][29][30][31][32][33]] Specific microvesicles (prostasomes (50 nm-0.5 µm), melanosomes (>0.5 µm), 'platelet dust' (~130-500 nm)) [33][34][35][36][37] Membrane-free microparticles High-density lipoproteins (HDL) [23,[38][39][40][41][42] Low-density lipoproteins (LDL) [39,40,42] Various RNA-binding proteins (for example, AGO1, AGO2, nucleophosmin 1 (NPM1), Tamm-Horsfall protein (THP), etc.) [23,[43][44][45][46][47][48]…”

“…Membrane-coated microparticles Apoptotic bodies (0. [17,18,22,24,[27][28][29][30][31][32][33]] Specific microvesicles (prostasomes (50 nm-0.5 µm), melanosomes (>0.5 µm), 'platelet dust' (~130-500 nm)) [33][34][35][36][37] Membrane-free microparticles High-density lipoproteins (HDL) [23,[38][39][40][41][42] Low-density lipoproteins (LDL) [39,40,42] Various RNA-binding proteins (for example, AGO1, AGO2, nucleophosmin 1 (NPM1), Tamm-Horsfall protein (THP), etc.) [23,[43][44][45][46][47][48][49] Exomeres (~35 nm (<50 nm)) [50,51] miRNAs associated with the surface of blood cells [27,32]…”

“…Additionally, recent data suggests that a subpopulation of cf-miRNA circulates bound to the surface blood cells ( Table 2 ). This miRNA fraction is perspective as a source of diagnostic markers because the expression of some cell surface bonded miRNAs changes with the development of cancer [ 27 , 32 ].…”