Mesenchymal stem cell-derived exosomes enriched with miR-218 reduce the epithelial-mesenchymal transition and angiogenesis in triple-negative breast cancer cells

BACKGROUND

The epithelial-mesenchymal transition (EMT) and angiogenesis are morphogenetic processes implicated in tumor invasion and metastasis. It is found that the aberrant expression of microRNAs (miRNAs) contributes to these processes. Exosomes are considered potential natural vehicles for miRNA delivery in cancer therapy. miR-218 is one of the tumor suppressor miRNAs and its downregulation is associated with EMT and angiogenesis. We aimed to use adipose mesenchymal stem cells-derived exosomes (ADMSC-exosomes) for miR-218 delivery to breast cancer cells and evaluate miR-218 tumor-suppressing properties in vitro.

METHODS

Exosomes were isolated from conditioned media of ADMSCs. miR-218 was loaded to exosomes using electroporation. mRNA expression of target genes (Runx2 and Rictor) in MDA-MB-231 breast cancer cells was evaluated by qPCR. To explore the effects of miR-218 containing exosomes on breast cancer cells, viability, apoptosis, and Boyden chamber assays were performed. The angiogenic capacity of MDA-MB-231 cells after treatment with miR-218 containing exosomes was assessed by in vitro tube formation assay.

RESULTS

miR-218 mimic was efficiently loaded to ADMSC-exosomes and delivered to MDA-MB-231 cells. Exposure to miR-218 containing exosomes significantly decreased miR-218 target genes (Runx2 and Rictor) in MDA-MB-231 cells. They increased the expression of epithelial marker (CDH1) and reduced mesenchymal marker (CDH2). miR-218 restoration using miR-218 containing exosomes reduced viability, motility, invasion, and angiogenic capacity of breast cancer cells.

CONCLUSIONS

These findings suggest that ADMSC-exosomes can efficiently restore miR-218 levels in breast cancer cells and miR-218 can prevent breast cancer progression with simultaneous targeting of angiogenesis and EMT.

Exosomes derived from rapamycin-treated 4T1 breast cancer cells induced polarization of macrophages to M1 phenotype

M2 macrophages are the most prevalent type in the tumor microenvironment and their polarization to M1 type can be used as a potential cancer immunotherapy. Here, we investigated the role of tumor microenvironment and particularly purified exosomes in M2 to M1 macrophage polarization. Rapamycin treatment on triple-negative breast cancer cells (TNBC) was performed. Tumor cells-derived exosomes (called texosomes) were isolated and characterized using scanning electron microscopy, transmission electron microscopy, dynamic light scattering, high-performance liquid chromatography, Fourier transform infrared, and Western blot assays. M2 mouse peritoneal macrophages were treated with rapamycin or rapamycin-texosome. Then, M1/M2 phenotype-specific marker genes and proteins were measured to assess the degree of M2 to M1 polarization. Finally, nitric oxide (NO) production, phagocytosis, and efferocytosis assays were assessed to verify the functionality of the polarized macrophages. Purified rapamycin-texosomes significantly increased the expression of the M1 markers (Irf5, Nos2, and CD86) and decreased M2 markers (Arg, Ym1, and CD206). In addition, the levels of M1-specific cytokines tumor necrosis factor alpha and interleukin 1β (IL-1β) were increased, whereas the levels of M2 specific cytokines IL-10 and transforming growth factor beta were declined. Furthermore, texosome treatment increased NO concentration and phagocytosis and decreased efferocytosis indicating M1 polarization. These findings suggest rapamycin-texosomes can induce M2 to M1 macrophages polarization as a potential immunotherapy for TNBC.

Overexpression of Pigment epithelium-derived factor in breast cancer cell-derived exosomes induces M1 polarization in macrophages

M2 macrophages, the major component of tumor microenvironment, are recognized as important player in tumor progression. M2 macrophages mediate this effect by promoting tumor angiogenesis, tumor metastasis, and suppression of tumor immunity. Reprogramming of M2 macrophages can serve as a promising strategy in cancer immunotherapy. In this study, we constructed pigment epithelium-derived factor (PEDF) expressing vector and transfected MDA-MB-231 cells with this construct. Then, exosomes were isolated from transfected cells and M2 macrophages were incubated with isolated exosomes from transfected cell. The effect of isolated exosomes on macrophage polarization was examined by real-time PCR and ELISA. The results demonstrated reprogramming of M2 macrophages after incubation with isolated exosomes from PEDF transfected cells. M2-to-M1 repolarization of macrophages was confirmed by upregulation of CD80, IRF5, MCP1, and IL-1β and repression of CD206, Arg, TGM2, and TGF-β. Therefore, these findings revealed that introducing PEDF into exosomes by genetic manipulation of parent cells may be a potential approach for reprogramming of M2 macrophages in cancer.

Transfer of miRNA in tumor-derived exosomes suppresses breast tumor cell invasion and migration by inducing M1 polarization in macrophages

AIMS

Macrophage repolarization from M1 to M2 phenotype is one of the hallmarks of malignancy. M2 macrophages are the most represented population in the tumor microenvironment and play an active role in tumor progression. In recent years, microRNAs (miRNAs) have been identified as a regulator of macrophage polarization.

MAIN METHODS

In this study, miR-130 was delivered to M2 macrophages using tumor-derived exosomes. Then, we evaluated the macrophage polarization status by assessment of specific markers and cytokines for M1 and M2 phenotype. The phagocytosis ability of macrophages was also investigated. Additionally, we performed migration and invasion assays to detect the effect of macrophage reprogramming on breast cancer cells migration and invasion.

KEY FINDINGS

The findings of the current study indicated that exosomes efficiently delivered miR-130 into macrophages. Delivery of miR-130 into macrophages resulted in upregulation of M1 specific markers and cytokines, including CD86, Irf5, Nos2, TNF-α, and IL-1β and downregulation of M2 specific markers and cytokines, including CD206, Ym1, Arg, TGF-β, and IL-10. The phagocytosis ability of macrophages also enhanced after treatment with miRNA-loaded exosomes. Furthermore, migration and invasion assays demonstrated reduced ability of 4T1 breast cancer cells for migration and invasion after macrophages reprogramming.

SIGNIFICANCE

These observations suggest that repolarization of M2 macrophages to M1 phenotype using miRNA-containing exosomes can be a therapeutic strategy against tumor invasion and metastasis in breast cancer.

In vitro and in vivo evaluation of anti-tumoral effect of M1 phenotype induction in macrophages by miR-130 and miR-33 containing exosomes

In the tumor microenvironment, macrophages polarize into the M2 phenotype to facilitate tumorigenesis. Tumor-derived exosomes can act as mediators between the tumor microenvironment and stromal cells by transporting proteins, mRNAs, and miRNAs. Exosomal miRNAs play a pivotal role in modulating tumor microenvironment and macrophage polarization. Here, we overexpressed miR-130 and miR-33 in exosomes of MDA-MB-231 cells and investigated their effect on macrophage polarization and tumor progression. For this purpose, exosomes were extracted from MDA-MB-231 cells and characterized using dynamic light scattering, electron microscopy, and western blotting of exosomal markers. Then, miR-130 or miR-33 containing exosomes were used to treat IL4-induced M2 or tumor-associated macrophages (TAMs). After treatment, the polarization status of macrophages, including the expression of M1 specific genes, and the secretion of cytokines were evaluated. Finally, the conditioned medium from exosome-treated macrophages was incubated with cancer cells to evaluate its effect on the migration and invasion ability of cancer cells and, in vivo experiments investigated the effect of exosome-treated macrophages on breast cancer progression. Exosomes characterization results approved the range of size and homogeneity of extracted exosomes. Overexpression of miR-130 and miR-33 in exosomes increased the expression of M1 signature genes (IRF5, MCP1, CD80) and secretion of cytokines (IL-1β and TNF-α) as well as yeast phagocytic activity of macrophages. Besides, the conditioned medium of macrophages treated with miRNA containing exosomes declined the migration and invasion ability of cancer cells. The in vivo results indicated the inhibitory effect of exosome-treated macrophages on tumor growth. Furthermore, the results showed that in response to exosome-treated macrophages, the production of TNF-α by spleen cells increased, while the production of IL-10 and TGF-β by these cells decreased. These findings suggest that overexpression of miR-130 and miR-33 in exosomes can decrease tumor progression by shifting macrophage polarization from M2 to M1 phenotype and can be a potential therapeutic strategy for tumor interventions.

Small supernumerary marker chromosomes and their correlation with specific syndromes

A small supernumerary marker chromosome (sSMC) is a structurally abnormal chromosome. It is an additional chromosome smaller than one chromosome most often lacking a distinct banding pattern and is rarely identifiable by conventional banding cytogenetic analysis. The origin and composition of an sSMC is recognizable by molecular cytogenetic analysis. These sSMCs are seen in different shapes, including the ring, centric minute, and inverted duplication shapes. The effects of sSMCs on the phenotype depend on factors such as size, genetic content, and the level of the mosaicism. The presence of an sSMC causes partial tris- or tetrasomy, and 70% of the sSMC carriers are clinically normal, while 30% are abnormal in some way. In 70% of the cases the sSMC is de novo, in 20% it is inherited from the mother, and in 10% it is inherited from the father. An sSMC can be causative for specific syndromes such as Emanuel, Pallister-Killian, or cat eye syndromes. There may be more specific sSMC-related syndromes, which may be identified by further investigation. These 10 syndromes can be useful for genetic counseling after further study.