Interferon Consensus Sequence-Binding Protein 8, a Tumor Suppressor, Suppresses Tumor Growth and Invasion of Non-Small Cell Lung Cancer by Interacting with the Wnt/β-Catenin Pathway

Abstract

Background/Aims: Interferon consensus sequence-binding protein 8 (IRF8) belongs to a family of interferon (IFN) regulatory factors that modulates various important physiological processes including carcinogenesis. As reported by others and our group, IRF8 expression is silenced by DNA methylation in both human solid tumors and hematological malignancies. However, the role of IRF8 in lung carcinoma remains elusive. In this study, we determined IRF8 epigenetic regulation, biological functions, and the signaling pathway involved in non-small cell lung cancer (NSCLC). Methods: IRF8 expression were determined by Q- PCR. MSP and A+T determined promotor methylation. MTS, clonogenic, Transwell assay, Flow cytometry, three-dimensional culture and AO/EB stain verified cell function. In vivo tumorigenesis examed the in vivo effects. By Chip-QPCR, RT-PCR, Western blot and Immunofluorescence staining, the mechanisms were studied. Results: IRF8 was significantly downregulated in lung tumor tissues compared with adjacent non-cancerous tissues. Furthermore, methylation-specific PCR analyses revealed that IRF8 methylation in NSCLC was a common event, and demethylation reagent treatment proved that downregulation of IRF8 was due to its promoter CpG hypermethylation. Clinical data showed that the IRF8 methylation was associated with tumor stage, lymph node metastasis status, patient outcome, and tumor histology. Exogenous expression of IRF8 in the silenced or downregulated lung cancer cell lines A549 and H1299 at least partially restored the sensitivity of lung cancer cells to apoptosis, and arrested cells at the G0/G1 phase. Cell viability, clonogenicity, and cell migration and invasive abilities were strongly inhibited by restored expression of IRF8. A three-dimensional culture system demonstrated that IRF8 changed the cells to a more spherical phenotype. Moreover, ectopic expression of IRF8 enhanced NSCLC chemosensitivity to cisplatin. Furthermore, as verified by Chip-qPCR, immunofluorescence staining, and western blotting, IRF8 bound to the T-cell factor/lymphoid enhancer factor (TCF /LEF) promoter, thus repressing β-catenin nuclear translocation and its activation. IRF8 significantly disrupted the effects of Wnt agonist, bml284, further suggesting its involvement in the Wnt/β-catenin pathway. Conclusion: IRF8 acted as a tumor suppressor gene through the transcriptional repression of β-catenin-TCF/LEF in NSCLC. IRF8 methylation may serve as a potential biomarker in NSCLC prognosis.

1,25-Dihydroxyvitamin D3 Prevents Epithelial-Mesenchymal Transition of HMrSV5 Human Peritoneal Mesothelial Cells by Inhibiting Histone Deacetylase 3 (HDAC3) and Increasing Vitamin D Receptor (VDR) Expression Through the Wnt/β-Catenin Signaling Pathway

“…Cells in the control group were maintained in serum-free DMEM medium. For the experimental groups, HMrSV5 cells were treated with high glucose (25 μM) and lipopolysaccharide (LPS0, 910 μg/ml) for 24 h. As for the role of 1,25(OH) 2 D3, HMrSV5 cells were pre-incubated with 1,25(OH) 2 D3 (10 −6 mol/L) for 2 h and subsequently treated with high glucose (25 μM) and LPS (10 μg/ml) for 24 h. Wnt agonist 1, 0.7 μM for 12 h (MedChem Express, Monmouth Junction, NJ, USA) was also used, as previously described [23]. Glucose, LPS, and 1,25(OH) 2 D3 were purchased from Sigma-Aldrich (St. Louis, MO, USA).…”

Efficacy of Dorsal Root Ganglion Pulsed Radiofrequency Combined with Paravertebral Injection of Recombinant Human Interferon-α2b in Herpetic Neuralgia

“…Interferon is a cytokine synthesized and secreted by immune cells, glial cells, and neuronal cells, and has antiviral, antitumor and immunomodulatory effects. 9 At present, the clinical use of intramuscular or subcutaneous injection for herpes zoster has a certain therapeutic effect, but systemic medication often has adverse reactions such as fever, allergy, and cytopenia. Guo et al 10 reported low-dose recombinant human interferon-α2b is used for the treatment of herpes zoster in patients with herpes zoster.…”

Combined Methylome and Transcriptome Analyses Reveals Potential Therapeutic Targets for EGFR Wild Type Lung Cancers with Low PD-L1 Expression

“…Similarly, we found that hypermethylated DMRs in 3 regions (TSS200, TSS1500, and gene body) are significantly higher than hypomethylated ones. Furthermore, 15 tumor suppressor genes belonging to the HyperDown group were identified, of which CDO1 (Cysteine Dioxygenase Type 1) [ 59 , 60 ], IRF8 (Interferon Regulatory Factor 8) [ 61 ], STAT5A (Signal Transducer And Activator Of Transcription 5A) [ 62 ], CFTR (CF Transmembrane Conductance Regulator) [ 63 ], ADAMTS8 (ADAM Metallopeptidase With Thrombospondin Type 1 Motif 8) [ 64 ], WIF1 (WNT Inhibitory Factor 1) [ 65 ], GATA5 (GATA Binding Protein 5) [ 66 ], FOXA2 (FOXA2) [ 67 ], SHISA3 (Shisa Family Member 3) [ 68 ], AXIN2 (Axin 2) [ 69 ], DIRAS3 (DIRAS family GTPase 3) [ 70 ], IRX1 (Iroquois Homeobox 1) [ 71 ], and ITGA5 (Integrin Subunit Alpha 5) [ 72 ] are confirmed by previous studies to be silenced via hypermethylation in lung cancer ( Tables S1–S3 ). Although the tumor suppressor CAMK2N1 (Calcium/Calmodulin Dependent Protein Kinase II Inhibitor 1) has not been associated with lung cancer yet, its hypermethylation has been shown to promote tumorigenesis in other cancers [ 73 ].…”