RESUMO
BACKGROUND: Hepatocellular carcinoma (HCC) cells-secreted exosomes (exo) could stimulate M2 macrophage polarization and promote HCC progression, but the related mechanism of long non-coding RNA distal-less homeobox 6 antisense 1 (DLX6-AS1) with HCC-exo-mediated M2 macrophage polarization is largely ambiguous. Thereafter, this research was started to unearth the role of DLX6-AS1 in HCC-exo in HCC through M2 macrophage polarization and microRNA (miR)-15a-5p/C-X-C motif chemokine ligand 17 (CXCL17) axis. METHODS: DLX6-AS1, miR-15a-5p and CXCL17 expression in HCC tissues and cells were tested. Exosomes were isolated from HCC cells with overexpressed DLX6-AS1 and co-cultured with M2 macrophages. MiR-15a-5p/CXCL17 down-regulation assays were performed in macrophages. The treated M2 macrophages were co-cultured with HCC cells, after which cell migration, invasion and epithelial mesenchymal transition were examined. The targeting relationships between DLX6-AS1 and miR-15a-5p, and between miR-15a-5p and CXCL17 were explored. In vivo experiment was conducted to detect the effect of exosomal DLX6-AS1-induced M2 macrophage polarization on HCC metastasis. RESULTS: Promoted DLX6-AS1 and CXCL17 and reduced miR-15a-5p exhibited in HCC. HCC-exo induced M2 macrophage polarization to accelerate migration, invasion and epithelial mesenchymal transition in HCC, which was further enhanced by up-regulated DLX6-AS1 but impaired by silenced DLX6-AS1. Inhibition of miR-15a-5p promoted M2 macrophage polarization to stimulate the invasion and metastasis of HCC while that of CXCL17 had the opposite effects. DLX6-AS1 mediated miR-15a-5p to target CXCL17. DLX6-AS1 from HCC-exo promoted metastasis in the lung by inducing M2 macrophage polarization in vivo. CONCLUSION: DLX6-AS1 from HCC-exo regulates CXCL17 by competitively binding to miR-15a-5p to induce M2 macrophage polarization, thus promoting HCC migration, invasion and EMT.
Assuntos
Carcinoma Hepatocelular/metabolismo , Quimiocinas CXC/metabolismo , Neoplasias Hepáticas/metabolismo , Macrófagos/metabolismo , MicroRNAs/metabolismo , RNA Longo não Codificante/metabolismo , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Movimento Celular/fisiologia , Polaridade Celular/fisiologia , Quimiocinas CXC/genética , Exossomos/metabolismo , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Macrófagos/patologia , Masculino , Camundongos , Camundongos Nus , MicroRNAs/genética , Invasividade Neoplásica , RNA Longo não Codificante/genética , Transdução de SinaisRESUMO
Krüppel-like factor 8 (KLF8) is highly expressed in hepatocellular carcinoma (HCC) and contributes to tumor initiation and progression by promoting HCC cell proliferation and invasion. However, the role of KLF8 in liver cancer stem cells (LCSCs) is not known. In the current study, we investigated the role of KLF8 in LCSCs to determine if KLF8 is a novel marker of these cells. We found that KLF8 was highly expressed in primary HCC tumors, distant migrated tissues, and LCSCs. Patients with high KLF8 expression had a poor prognosis. KLF8 promoted stem cell-like features through activation of the Wnt/ß-catenin signaling pathway. Cell apoptosis was significantly increased in HCC cells with knockdown of KLF8 compared with the control cells when treated with the same doses of sorafenib or cisplatin. Taken together, our study shows that KLF8 plays a potent oncogenic role in HCC tumorigenesis by maintaining stem cell-like features through activation of the Wnt/ß-catenin signaling pathway and promoting chemoresistance. Thus, targeting KLF8 may provide an effective therapeutic approach to suppress tumorigenicity of HCC. © 2016 Wiley Periodicals, Inc.
