Progress in mechanism of tumor-derived exosomes on myeloid-derived suppressor cells / 中华微生物学和免疫学杂志

Myeloid-derived suppressor cells (MDSCs) play an important immunosuppressive role in the tumor microenvironment. Tumor cells can regulate the immunosuppressive function of MDSCs in the tumor microenvironment through exosomes, thereby affecting the development of tumors. Tumor-derived exosomes (TEXs) promote the development of MDSCs and improve their immunosuppressive function in the tumor microenvironment mainly by participating in the processes such as intercellular information exchange and information transmission. Moreover, the miRNAs in TEXs will also be transferred to recipient cells to inhibit the immunosuppressive function of MDSCs by inducing the negative regulation of target genes. This review summarized the progress in the mechanism of TEXs on MDSCs.

Tumor-derived exosomes: Nanovesicles made by cancer cells to promote cancer metastasis

Nanomedicine usually refers to nanoparticles that deliver the functional drugs and siRNAs to treat cancer. Recent research has suggested that cancer cells can also make nanoparticles that also deliver functional molecules in promoting cancer metastasis, which is the leading cause of various cancer mortalities. This nanoparticle is called tumor-derived vesicles, or better-known as tumor-derived exosomes (TEXs). TEXs are nanoscale membrane vesicles (30-140 nm) that are released continuously by various types of cancer cells and contain tumor-derived functional biomolecules, including lipids, proteins, and genetic molecules. These endogenous TEXs can interact with host immune cells and epithelial cells locally and systemically. More importantly, they can reprogram the recipient cells in favor of promoting metastasis through facilitating tumor cell local invasion, intravasation, immune evasion, extravasation, and survival and growth in distant organs. Growing evidence suggests that TEXs play a key role in cancer metastasis. Here, we will review the most recent findings of how cancer cells harness TEXs to promote cancer metastasis through modulating vascular permeability, suppressing systemic immune surveillance, and creating metastatic niches. We will also summarize recent research in targeting TEXs to treat cancer metastasis.

Osteosarcoma-derived exosomes induces M2 polarization of macrophages and promotes metastasis of MG63 cells through Tim-3 / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To investigate the effect of exosomes derived from osteosarcoma on the differentiation of tumor-related macrophages and its mechanism. Methods: From March 2018 to October 2019, tumor tissues and corresponding normal tissues from 18 patients with primary osteosarcoma who underwent osteosarcoma resection and pathological diagnosis in the Departments of Orthopedics and Pediatric Surgery of the Affiliated Hospital of North Sichuan Medical College were collected. The expression level of Tim-3 was detected by Western blotting; Exosomes of osteosarcoma MG63 cells (MG63-Exo) were isolated and identified by transmission electron microscopy and nanoparticle size analysis, and its phagocytosis by macrophages was verified by Dual fluorescent staining; The effects of MG63-Exo on macrophage differentiation and the expression levels of IL-10, TGF-β and VEGF were detected by qPCR; The effects of MG63-Exo induced macrophages on the migration and invasion of MG63 cells and the expression of EMT related proteins were detected by Transwell invasion and migration assay and Western blotting; CRISPR/cas9 was used to knock out Tim-3 in MG63 cells, and its knockout efficiency was verified by Western blotting, and then qPCR, transwell assay and Western blotting were used to detect the effect of MG63-Exo with Tim-3 knock-out on macrophage differentiation, as well as migration, invasion and expression of EMT related proteins in MG63 cells; Finally, the mouse model of osteosarcoma lung metastasis was used to verify the effect of exosomes from different sources on the lung metastasis of osteosarcoma. Results: Transmission electron microscopy and nanoparticle size assay confirmed that MG63-Exo were successfully isolated, and Confocal fluorescence results confirmed that it could be phagocytized by macrophages; qPCR results showed that MG63-Exo significantly promoted M2 differentiation of macrophages compared with PBS (P<0.05); Compared with PBS control group, M2 macrophages induced by MG63-Exo significantly promoted the migration, invasion and EMT of osteosarcoma cells (all P<0.05); The mRNA and protein expressions of Tim-3 in the MG63 cells knocked out by CRISPR/cas9 (Tim-3-KO) were significantly reduced (all P<0.05), and Tim-3 could be transferred into macrophages in the form of exosomes; Compared with MG63-Exo co-cultured macrophages, the M2 type differentiation of macrophages treated with Tim-3-KO-exo was significantly decreased (P<0.05); Compared with the MG63 cells co-cultured with macrophages induced by MG63-Exo, the migration, invasion and EMT were significantly reduced while the lung metastasis was significantly promoted in MG63 cells co-cultured with macrophages induced by Tim-3-KO-Exo (all P<0.05). Conclusion: Exosomes derived from osteosarcoma can induce M2 polarization of macrophages through Tim-3 and promote the invasion and metastasis of tumor.

Mechanisms of tumor-derived exosomes promoting tumor metastasis / 国际肿瘤学杂志

Exosomes are microvesicles ranging from approximately 40-150 nm in size,which mediate the exchange of information between cells by releasing proteins,nucleic acids,etc.Tumor-derived exosomes (TEXs) may facilitate tumor metastasis through various mechanisms such as forming the premetastatic niche in the terminal organs,they can regulate immune cells and immune-related molecules in the tumor microenvironment to promote tumor immune escape,they can also induce tumor angiogenesis and increase vascular permeability,promoting the epithelial-mesenchymal transformation of tumor cells,etc.Understanding the mechanism of TEXs in tumor metastasis can provide new ideas for effective prevention and treatment of tumor metastasis.

Role of tumor-derived exosomes in tumor metastasis / 国际肿瘤学杂志

Tumor-derived exosomes (TEXs) are small membrane vesicles secreted by tumor cells.They contain various proteins and RNA which make they serve as functional mediators in cell interaction.TEXs can alter the components of extracellular matrix and induces epithelial-mesenchymal transition of tumor cells,which enhance the invasiveness of tumor cells.TEXs regulate immunity through multiple pathways,allowing circulating tumor cells to escape immune surveillance.TEXs promote pre-metastatic microenvironment in target organ before metastasis and induce angiogenesis after circulating tumor cells colonization.Understanding the role and mechanism of TEXs in this process can effectively block relevant signaling pathways which may provide new targeted therapies for clinic.