Hepatocellular carcinoma-derived exosomal miRNA-21 contributes to tumor progression by converting hepatocyte stellate cells to cancer-associated fibroblasts

Abstract

BackgroundHepatocellular carcinoma (HCC) remains a global challenge due to its high morbidity and mortality rates as well as poor response to treatment. The communication between tumor-derived elements and stroma plays a critical role in facilitating cancer progression of HCC. Exosomes are small extracellular vesicles (EVs) that are released from the cells upon fusion of multivesicular bodies with the plasma membrane. There is emerging evidence indicating that exosomes play a central role in cell-to-cell communication. Much attention has been paid to exosomes since they are found to transport bioactive proteins, messenger RNA (mRNAs) and microRNA (miRNAs) that can be transferred in active form to adjacent cells or to distant organs. However, the mechanisms underlying such cancer progression remain largely unexplored.MethodsExosomes were isolated by differential ultracentrifugation from conditioned medium of HCC cells and identified by electron microscopy and Western blotting analysis. Hepatic stellate cells (HSCs) were treated with different concentrations of exosomes, and the activation of HSCs was analyzed by Western blotting analysis, wound healing, migration assay, Edu assay, CCK-8 assay and flow cytometry. Moreover, the different miRNA levels of exosomes were tested by real-time quantitative PCR (RT-PCR). The angiogenic ability of activated HSCs was analyzed by qRT-PCR, CCK-8 assay and tube formation assay. In addition, the abnormal lipid metabolism of activated HSCs was analyzed by Western blotting analysis and Oil Red staining. Finally, the relationship between serum exosomal miRNA-21 and prognosis of HCC patients was evaluated.ResultsWe showed that HCC cells exhibited a great capacity to convert normal HSCs to cancer-associated fibroblasts (CAFs). Moreover, our data revealed that HCC cells secreted exosomal miRNA-21 that directly targeted PTEN, leading to activation of PDK1/AKT signaling in HSCs. Activated CAFs further promoted cancer progression by secreting angiogenic cytokines, including VEGF, MMP2, MMP9, bFGF and TGF-β. Clinical data indicated that high level of serum exosomal miRNA-21 was correlated with greater activation of CAFs and higher vessel density in HCC patients.ConclusionsIntercellular crosstalk between tumor cells and HSCs was mediated by tumor-derived exosomes that controlled progression of HCC. Our findings provided potential targets for prevention and treatment of live cancer.Electronic supplementary materialThe online version of this article (10.1186/s13046-018-0965-2) contains supplementary material, which is available to authorized users.

The role of cancer-derived microRNAs in cancer immune escape

“…Immunosuppressive [125] miR-24-3p NPC Immunosuppressive [126] miR-891a NPC Immunosuppressive [126] miR-106a-5p NPC Immunosuppressive [126] miR-20a-5p NPC Immunosuppressive [126] miR-1908 NPC Immunosuppressive [126] TAMs miR-222-3p EOC Immunosuppressive [127] miR-940 EOC Immunosuppressive [128] miR-21-3p EOC Immunosuppressive [129] miR-125b-5p EOC Immunosuppressive [129] miR-181d-5p EOC Immunosuppressive [129] miR-21 Head and neck cancer Immunosuppressive [130] miR-1246 Colon cancer Immunosuppressive [131] miR-16 Breast cancer Immunostimulatory [132] MDSCs miR-107 Gastric cancer Immunosuppressive [133] miR-21 OSCC Immunosuppressive [134] miR-21 Glioma Immunosuppressive [135] miR-10a Glioma Immunosuppressive [135] miR-29a Glioma Immunosuppressive [136] miR-92a Glioma Immunosuppressive [136] miR-155 CLL Immunosuppressive [137] CAFs miR-27a Gastric cancer Immunosuppressive [138] miR-1247-3p HCC Immunosuppressive [139] miR-21 HCC Immunosuppressive [140] NPC nasopharyngeal carcinoma, TAM tumor-associated macrophage, EOC epithelial ovarian cancer, MDSC myeloid-derived suppressor cell, OSCC oral squamous cell carcinoma, CLL chronic lymphocytic leukemia, CAF cancer-associated fibroblast, HCC hepatocellular carcinoma M2-like phenotype and suppressing the expression of M1 phenotype-associated markers [130]. Similarly, Cooks et al observed that cancer cells harboring TP53 mutation could reprogram neighboring TAMs into pro-tumor state via secreting miR-1246-enriched exosomes [131].…”

“…In addition, Fang et al found that metastatic hepatocellular carcinoma cells produced exosomal miR-1247-3p which could target B4GALT3 and activate β1-integrin-NF-κB signaling pathway in CAFs [139]. Besides, Zhou et al observed that hepatocellular carcinoma enhanced the activity of CAFs by exosomal miRNA-21-PTEN-PDK1/AKT pathway [140].…”

Potential roles of extracellular vesicles in the pathophysiology, diagnosis, and treatment of autoimmune diseases

“…For example, DCs loaded with exosomes and alphagalactosylceramide can significantly improve the tumor microenvironment of rats bearing gliomas and increase the median survival of rats [73]. In contrast, hepatocellular carcinoma-derived exosomes miR-21 are thought to convert normal hepatic stellate cells to cancer-associated fibroblasts, thereby promoting tumor progression, which may provide new targets for the prevention and treatment of liver cancer [74]. The latest evidence suggests that the ability of EVs to tissue regeneration is equally astonishing.…”

The cancer exosomes: Clinical implications, applications and challenges

“…sequenced and quantitated PCR and found that HCC cell‐derived exosomes transmitted miR‐103 into endothelial cells attenuated the endothelial junction integrity by downregulating VE‐Cadherin (VE‐Cad), p120‐catenin (p120) and zonula occludens 1 (Table ). Also, there is emerging evidence indicating that HCC‐derived exosomal miR‐21 targeting PTEN led to the activation of PDK1/AKT signaling in HSCs, which educated CAFs released angiogenic cytokines, including VEGF, MMP2, MMP9, bFGF and TGF‐beta (Table ) . To abate angiogenesis remains a severe challenge for tumor treatment.…”

“…Also, there is emerging evidence indicating that HCC-derived exosomal miR-21 targeting PTEN led to the activation of PDK1/AKT signaling in HSCs, which educated CAFs released angiogenic cytokines, including VEGF, MMP2, MMP9, bFGF and TGF-beta (Table 1). 54 To abate angiogenesis remains a severe challenge for tumor treatment. Wang et al 55 examined the expression of lncRNA-APC1 and unveiled that lncRNA-APC1 activated by APC suppressed CRC angiogenesis via targeting Rab5b mRNA, which could inhibit tumor angiogenesis in CRC (Table 1).…”