Extracellular vesicles secreted by hypoxia pre-challenged mesenchymal stem cells promote non-small cell lung cancer cell growth and mobility as well as macrophage M2 polarization via miR-21-5p delivery

Abstract

ObjectiveTo investigate the lung cancer-promoting mechanism of mesenchymal stem cell-secreted extracellular vesicles (MSC-EV).MethodsEV were isolated from culture media of human bone marrow-derived MSCs that were pre-challenged with or without hypoxia (referred to as H-EV and N-EV, respectively). After treatment with N-EV or H-EV, A549 and H23 cell proliferation, apoptosis, trans-well invasion and epithelial-to-mesenchymal transition (EMT) were examined. Polarization of human primary monocytes-derived macrophages with or without N-EV or H-EV induction were analyzed by flow cytometry and ELISA. PTEN, PDCD4 or RECK gene was overexpressed in A549 cells, while miR-21-5p was knocked down in MSCs, A549 or H23 lung cancer cells or primary monocytes by miR-21-5p inhibitor transfection. Protein level of PTEN, PDCD4, RECK, AKT or STAT3 as well as phosphorylation level of AKT or STAT3 protein were assayed by western blot. Tumorigenicity of A549 and H23 cells with or without MSC-EV co-injection was assayed on immunocompromised mice. The xenograft tumor were examined for cell proliferation, angiogenesis, apoptosis and intra-tumoral M1/M2 macrophage polarization.ResultsComparing to N-EV, H-EV treatment significantly increased A549 and H23 cell proliferation, survival, invasiveness and EMT as well as macrophage M2 polarization. MiR-21-5p knocked down significantly abrogated the cancer-promoting and macrophage M2 polarizing effects of H-EV treatment. H-EV treatment downregulated PTEN, PDCD4 and RECK gene expression largely through miR-21-5p. Overexpressing PTEN, PDCD4 and RECK in A549 cells significantly reduced the miR-21-5p-mediated anti-apoptotic and pro-metastatic effect of H-EV, while overexpressing PTEN in monocytes significantly reduced macrophage M2 polarization after induction with the presence of H-EV. H-EV co-injection significantly increased tumor growth, cancer cell proliferation, intra-tumoral angiogenesis and M2 polarization of macrophages in vivo partially through miR-21-5p.ConclusionsIncreased miR-21-5p delivery by MSC-EV after hypoxia pre-challenge can promote lung cancer development by reducing apoptosis and promoting macrophage M2 polarization.Electronic supplementary materialThe online version of this article (10.1186/s13046-019-1027-0) contains supplementary material, which is available to authorized users.

Macrophage M2 polarization induced by exosomes from adipose-derived stem cells contributes to the exosomal proangiogenic effect on mouse ischemic hindlimb

“…miRNAs in exosomes play an essential role in mediating cell-cell communication. Based on an extensive review of the literature, two dozen miRNAs were found to induce macrophage M2 polarization [34,35]. Among them, seven miRNAs were enriched in Hyp/Exo from ASCs, namely, miR-21, miR-223, Let-7c, miR-146b, miR-181a, miR-33, and miR-511-3p, according to our miRNA array results.…”

“…Exosomes from miR-21-downregulated cancer cells have also been observed to indirectly mitigate macrophage M2 polarization [36]. However, in the mouse macrophage cell line RAW264.7, the miR-21 mimic attenuates M2 polarization, while the miR-21 inhibitor augments M2 polarization [35]. This opposite observation may be caused by the immortalization and transformation of the cell line.…”

Ovatodiolide Suppresses Oral Cancer Malignancy by Down-Regulating Exosomal Mir-21/STAT3/β-Catenin Cargo and Preventing Oncogenic Transformation of Normal Gingival Fibroblasts

“…In this study, we explored the role of CSCs in the development of chemotherapeutic (cisplatin, CDDP) resistance in OSCC. Our review of the contemporary literature revealed that signaling molecules, including oncogenic microRNA (miR)-21-5p, components of the PI3K/mTOR/signal transducer and activator of transcription 3 (STAT3) signaling cascade, and transforming growth factor (TGF)-β1 were found in EVs derived from CSCs (CSC_EVs) [11][12][13][14]. Coculture of the SCC-15 and CAL27 parental OSCC cell lines with CSC_EVs was shown to promote malignant OSCC phenotypes, including enhanced migration, invasion, self-renewal, and CDDP resistance.…”

Role of microRNAs in remodeling the tumor microenvironment (Review)

“…At the late stage of human cancers, most of the infiltrating macrophages display an M2 phenotype, creating an immunosuppressive microenvironment that favors tumor progression. Increased miR-21-5p delivery by MSC-derived extracellular vesicles was recently reported to promote the polarization of macrophages towards an M2 phenotype (48). miR-125b binds to the 3' untranslated region of tumor necrosis factor-α (TNF-α), inhibiting its production and sustaining an M1 phenotype (49).…”