RESUMO
Non-small-cell lung cancer (NSCLC) remains the leading cause of cancer-related death worldwide. Accumulating researches have highlighted the ability of exosome-encapsulated microRNAs (miRNAs or miRs) as potential circulating biomarkers for lung cancer. The current study aimed to evaluate the significance of mesenchymal stem cells (MSCs)-derived exosomal miR-204 in the invasion, migration, and epithelial-mesenchymal transition (EMT) of NSCLC cells. Initially, the expression of miR-204 in human NSCLC tissues and cells was determined by RT-qPCR, which demonstrated that miR-204 was downregulated in NSCLC tissues and cells. Next, Krüppel-like factor 7 (KLF7) was predicted and validated to be a target of miR-204 using dual-luciferase reporter gene assay. NSCLC A549 cells were treated with MSCs-derived exosomes, after which the migration and invasion of A549 cells were detected and expression of EMT-related proteins (E-cadherin, N-cadherin, and Vimentin), KLF7, p-AKT/AKT, and HIF-1α were measured. The results of gain- and loss-of-function assays revealed that miR-204 overexpression in MSCs-derived exosomes inhibited KLF7 expression and the AKT/HIF-1α pathway activity, resulting in impaired cell migration, invasion, as well as EMT. In conclusion, the key findings of the current study demonstrate that exosomal miR-204 from MSCs possesses anticarcinogenic properties against NSCLC via the KLF7/AKT/HIF-1α axis.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Exossomos , Neoplasias Pulmonares , Células-Tronco Mesenquimais , MicroRNAs , Carcinoma Pulmonar de Células não Pequenas/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células , Transição Epitelial-Mesenquimal/genética , Exossomos/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia , Fatores de Transcrição Kruppel-Like/genética , Neoplasias Pulmonares/genética , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/genética , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismoRESUMO
Infection and inflammation serve an important role in tumor development. Tolllike receptor 4 (TLR4) is a pivotal component of the innate and adaptive immune response during infection and inflammation. Programmeddeath ligand 1 (PDL1) is hypothesized as an important factor for nonsmall cell lung cancer (NSCLC) immune escape. In the present study, the relationship between TLR4 and PDL1, in addition to the associated molecular mechanism, were investigated. TLR4 and PDL1 expression in lung cancer tissues were detected using immunohistochemistry, whilst overall patient survival was measured using the KaplanMeier method. The A549 cell line stimulated using lipopolysaccharide (LPS) was applied as the in vitro inflammatory NSCLC model. Associated factors were investigated using reverse transcriptionquantitative PCR and western blotting. Lung cancer tissues exhibited increased PDL1 and TLR4 levels compared with those of adjacent paracancerous tissues, where there was a positive correlation between TLR4 and PDL1 expression. In addition, increased expression of these two proteins was found to be linked with poorer prognoses. Following the stimulation of A549 cells with LPS, TLR4 and PDL1 expression levels were revealed to be upregulated in a dosedependent manner, where the ERK and PI3K/AKT signaling pathways were found to be activated. Interestingly, in the presence of inhibitors of these two pathways aforementioned, upregulation of PDL1 expression was only inhibited by the MEK inhibitor PD98059, which can inhibit ERK activity. These data suggested that the ERK signaling pathway is necessary for the TLR4/PDL1 axis. In conclusion, data from the present study suggest that TLR4 and PDL1 expression can serve as important prognostic factors for NSCLC, where TLR4 activation may induce PDL1 expression through the ERK signaling pathway.