miR-124-3p enhances dendritic cell-mediated anti-tumor immunity by targeting CYLD/4-1BBL pathway

Abstract Objective: To investigate miR-124-3p regulation of DC-mediated immune response via CYLD/4-1BBL pathway, and the inhibitory effect of miR-124-3p on lung cancer.Methods: DCs were cultured and amplified in vitro, and then transfected with miR-124-3p mimic, miR-124-3P inhibitor, or siRNA CYLD. Double luciferase reporter genes were used to detect the target relationship between miR-124-3p and CYLD. qRT-PCR and western blotting were used to detect the expression levels of CYLD and 4-1BBL. Flow cytometry was used to assess the proliferation rate of CD4+ T cells co-cultured with untransfected DCs and those transfected with miR-124-3p mimic or miR-124-3p inhibitor. C57BL/6 tumor bearing mice, implanted with LL/2 lung adenocarcinoma cells, were administered DCs transfected with the miR-124-3p mimic or untransfected DCs. The tumor size and weight of mice were then measured. Results: miR-124-3p and CYLD3’UTR contained target-binding site, and overexpression of miR-124-3p enhanced the expression of CYLD and 4-1BBL. CD4+ T cells co-cultured with miR-124-3p mimic-transfected DCs showed significantly increased proliferation. In tumor-bearing mice, tumor inhibition rate was 73.5%, and tumor volume and weight were significantly decreased after the administration of DCs containing the miR-124-3p mimic.Conclusions: The expression of CYLD was regulated by miR-124-3p, which, in turn, increased the expression of 4-1BBL. miR-124-3p regulated DCs function via CYLD/4-1BBL cascade. miR-124-3p plays important roles in DCs-induced T cells, thereby enhancing anti-tumor immunity.