IκB kinase α functions as a tumor suppressor in epithelial-derived tumors through an NF-κB-independent pathway (Review)

Identification of miRNAs as the Crosstalk in the Interaction between Neural Stem/Progenitor Cells and Endothelial Cells

AIM

This study is aimed at identifying genetic and epigenetic crosstalk molecules and their target drugs involved in the interaction between neural stem/progenitor cells (NSPCs) and endothelial cells (ECs).

MATERIALS AND METHODS

Datasets pertaining to reciprocal mRNA and noncoding RNA changes induced by the interaction between NSPCs and ECs were obtained from the GEO database. Differential expression analysis (DEA) was applied to identify NSPC-induced EC alterations by comparing the expression profiles between monoculture of ECs and ECs grown in EC/NSPC cocultures. DEA was also utilized to identify EC-induced NSPC alterations by comparing the expression profiles between monoculture of NSPCs and NSPCs grown in EC/NSPC cocultures. The DEGs and DEmiRNAs shared by NSPC-induced EC alterations and EC-induced NSPC alterations were then identified. Furthermore, miRNA crosstalk analysis and functional enrichment analysis were performed, and the relationship between DEmiRNAs and small molecular drug targets/environment chemical compounds was investigated.

RESULTS

One dataset (GSE29759) was included and analyzed in this study. Six genes (i.e., MMP14, TIMP3, LOXL1, CCK, SMAD6, and HSPA2), three miRNAs (i.e., miR-210, miR-230a, and miR-23b), and three pathways (i.e., Akt, ERK1/2, and BMPs) were identified as crosstalk molecules. Six small molecular drugs (i.e., deptropine, fluphenazine, lycorine, quinostatin, resveratrol, and thiamazole) and seven environmental chemical compounds (i.e., folic acid, dexamethasone, choline, doxorubicin, thalidomide, bisphenol A, and titanium dioxide) were identified to be potential target drugs of the identified DEmiRNAs.

CONCLUSION

To conclude, three miRNAs (i.e., miR-210, miR-230a, and miR-23b) were identified to be crosstalks linking the interaction between ECs and NSPCs by implicating in both angiogenesis and neurogenesis. These crosstalk molecules might provide a basis for devising novel strategies for fabricating neurovascular models in stem cell tissue engineering.

LncRNA VINAS regulates atherosclerosis by modulating NF-κB and MAPK signaling

Long noncoding RNAs (lncRNAs) play important roles in regulating diverse cellular processes in the vessel wall, including atherosclerosis. RNA-Seq profiling of intimal lesions revealed a lncRNA, VINAS (Vascular INflammation and Atherosclerosis lncRNA Sequence), that is enriched in the aortic intima and regulates vascular inflammation. Aortic intimal expression of VINAS fell with atherosclerotic progression and rose with regression. VINAS knockdown reduced atherosclerotic lesion formation by 55% in LDL receptor-deficient (LDLR-/-) mice, independent of effects on circulating lipids, by decreasing inflammation in the vessel wall. Loss- and gain-of-function studies in vitro demonstrated that VINAS serves as a critical regulator of inflammation by modulating NF-κB and MAPK signaling pathways. VINAS knockdown decreased the expression of key inflammatory markers, such as MCP-1, TNF-α, IL-1β, and COX-2, in endothelial cells (ECs), vascular smooth muscle cells, and bone marrow-derived macrophages. Moreover, VINAS silencing decreased expression of leukocyte adhesion molecules VCAM-1, E-selectin, and ICAM-1 and reduced monocyte adhesion to ECs. DEP domain containing 4 (DEPDC4), an evolutionary conserved human ortholog of VINAS with approximately 74% homology, showed similar regulation in human and pig atherosclerotic specimens. DEPDC4 knockdown replicated antiinflammatory effects of VINAS in human ECs. These findings reveal a potentially novel lncRNA that regulates vascular inflammation, with broad implications for vascular diseases.

IκB kinase α: an independent prognostic factor that promotes the migration and invasion of oral squamous cell carcinoma

IκB kinase α (IKKα) is associated with tumourigenesis, metastasis, and poor prognosis. However, its expression and function in oral squamous cell carcinoma (SCC) remain unknown. The aim of this study was to elucidate the clinicopathological associations and functions of IKKα in oral squamous cell carcinoma (SCC). We made an immunohistochemical analysis of IKKα in 94 tissue microarrays of specimens of oral SCC. We also examined IKKα expression in the patients' samples by quantitative real-time polymerase chain reaction (qRT-PCR), as well as the migration, invasion, and matrix metalloproteinase (MMP) activity of the cells under IKKα knockdown treatment. In oral SCC, immunostaining for IKKα was found in 60 of the 94 patients, and it correlated with lymph node status and poor prognosis. Univariate and multivariate analysis using Cox's proportional hazards model identified that IKKα expression was an independent predictor of distant- disease-free survival (p<0.05) and overall survival in oral SCC (p<0.05). Knocking down IKKα suppressed cell migration and invasion in oral SCC cells. Our results indicate that IKKα has an important role in promoting oral SCC, and it may be a useful biomarker and therapeutic target for diagnosis and treatment.

Prognostic values of inhibitory κB kinases mRNA expression in human gastric cancer

Background: Inhibitory κB kinases (IKKs) play a key role in modulating proinflammatory and growth stimulating signals through their regulation of the nuclear factor κB (NF-κB) cascade. Therefore, the level of expression of IKKs represents a viable prognostic predictor with regard to various pathological processes. The prognostic value of IKKs expression in gastric cancer remains unclear. Methods: We used the 'Kaplan-Meier plotter' (KM plotter) online database, to explore the predictive prognostic value of individual IKKs members' mRNA expression to overall survival (OS) in different clinical data including pathological staging, histology, and therapies employed. Results: Our results revealed that a higher mRNA expression of inhibitor of NF-κB kinase subunit α (IKKα) was correlated to better OS, whereas higher mRNA expression of IKKβ, inhibitor of NF-κB kinase subunit γ (IKKγ), inhibitor of NF-κB kinase subunit ε (IKKε), and suppressor of IKKε (SIKE) were generally correlated to unfavorable OS in gastric cancer. Increased mRNA expression of IKKε also showed better outcomes in stage IV gastric cancer. Further a correlation between elevated levels of mRNA expression of both IKKε and SIKE was found to have favorable OS in diffuse type gastric cancer. It was also revealed that high expression of SIKE had favorable OS when treated with other adjuvant therapies, while worse OS when treated only with 5FU therapy. Conclusion: Our results suggest that mRNA expression of individual IKKs and SIKE are associated with unique prognostic significance and may act as valuable prognostic biomarkers and potential targets for future therapeutic interventions in gastric cancer.

Persistent IKKα phosphorylation induced apoptosis in UVB and Poly I:C co-treated HaCaT cells plausibly through pro-apoptotic p73 and abrogation of IκBα

Toll-like receptor 3 (TLR3), a member of pattern recognition receptors, is reported to initiate skin inflammation by recognizing double-strand RNA (dsRNA) released from UVB-irradiated cells. Recently, we have discovered the NF-κB pathway activated by TLR3 is involved in apoptosis of UVB-Poly I:C-treated HaCaT cells. The real culprit for apoptosis has not been precisely identified since the system of NF-κB pathway is complex. In this study, we silenced main transcriptional factors in NF-κB family, RelA, RelB and c-Rel, but to our surprise the results show that none of them participate in apoptosis induction in UVB-Poly I:C-treated HaCaT cells. Therefore, we moved to investigate the apoptosis-associated molecules in the upstream of NF-κB pathway. We firstly checked the expression of IκBα, an NF-κB inhibitor. UVB (4.8 mJ/cm²) and Poly I:C (0.3 μg/mL) co-treatment decreased IκBα expression level in a time-dependent manner. Silencing IκBα with siRNA further enhanced UVB-Poly I:C-induced cell death. We then investigated IκB kinase (IKK) complex that contributes to the degradation of IκBα. IKK is composed of IKKα, IKKβ and NEMO. Treatment with IKK-16, an IKKα/β inhibitor, significantly diminished UVB-Poly I:C-induced IκBα degradation and thus apoptosis. Silencing either IKKα or NEMO but not IKKβ with corresponding siRNA inhibited apoptosis. Tumor repressor p73, a homologue of p53, is reported to mediate IKKα-induced apoptosis in DNA damage response. Silencing p73 reduced cell apoptosis in UVB-Poly I:C-treated HaCaT cells. In summary, UVB and Poly I:C co-treatment activates IKKα and NEMO, which diminishes anti-apoptotic IκBα, resulting in enhancement of apoptosis through p73. The findings partially clarify the possible molecular mechanism of pro-apoptotic NF-κB pathway activated by TLR3 in the fate of UVB-irradiated epidermis.

Roles of NF-κB Signaling in the Regulation of miRNAs Impacting on Inflammation in Cancer

The NF-κB family of transcription factors regulate the expression of genes encoding proteins and microRNAs (miRNA, miR) precursors that may either positively or negatively regulate a variety of biological processes such as cell cycle progression, cell survival, and cell differentiation. The NF-κB-miRNA transcriptional regulatory network has been implicated in the regulation of proinflammatory, immune, and stress-like responses. Gene regulation by miRNAs has emerged as an additional epigenetic mechanism at the post-transcriptional level. The expression of miRNAs can be regulated by specific transcription factors (TFs), including the NF-κB TF family, and vice versa. The interplay between TFs and miRNAs creates positive or negative feedback loops and also regulatory networks, which can control cell fate. In the current review, we discuss the impact of NF-κB-miRNA interplay and feedback loops and networks impacting on inflammation in cancer. We provide several paradigms of specific NF-κB-miRNA networks that can regulate inflammation linked to cancer. For example, the NF-κB-miR-146 and NF-κB-miR-155 networks fine-tune the activity, intensity, and duration of inflammation, while the NF-κB-miR-21 and NF-κB-miR-181b-1 amplifying loops link inflammation to cancer; and p53- or NF-κB-regulated miRNAs interconnect these pathways and may shift the balance to cancer development or tumor suppression. The availability of genomic data may be useful to verify and find novel interactions, and provide a catalogue of 162 miRNAs targeting and 40 miRNAs possibly regulated by NF-κB. We propose that studying active TF-miRNA transcriptional regulatory networks such as NF-κB-miRNA networks in specific cancer types can contribute to our further understanding of the regulatory interplay between inflammation and cancer, and also perhaps lead to the development of pharmacologically novel therapeutic approaches to combat cancer.

Ginkgolide C Alleviates Myocardial Ischemia/Reperfusion-Induced Inflammatory Injury via Inhibition of CD40-NF-κB Pathway

Increasing evidence shows that inflammation plays a vital role in the occurrence and development of ischemia/reperfusion (I/R). Suppression of excessive inflammation can ameliorate impaired cardiac function, which shows therapeutic potential for clinical treatment of myocardial ischemia/reperfusion (MI/R) diseases. In this study, we investigated whether Ginkgolide C (GC), a potent anti-inflammatory flavone, extenuated MI/R injury through inhibition of inflammation. In vivo, rats with the occlusion of the left anterior descending (LAD) coronary artery were applied to mimic MI/R injury. In vitro, primary cultured neonatal ventricular myocytes exposed to hypoxia/reoxygenation (H/R) were applied to further discuss the anti-H/R injury property of GC. The results revealed that GC significantly improved the symptoms of MI/R injury, as evidenced by reducing infarct size, preventing myofibrillar degeneration and reversing the mitochondria dysfunction. Moreover, histological analysis and Myeloperoxidase (MPO) activity measurement showed that GC remarkably suppressed Polymorphonuclears (PMNs) infiltration and ameliorated the histopathological damage. Furthermore, GC pretreatment was shown to improve H/R-induced ventricular myocytes viability and enhance tolerance of inflammatory insult, as evidenced by suppressing expression of CD40, translocation of NF-κB p65 subunit, phosphorylation of IκB-α, as well as the activity of IKK-β. In addition, downstream inflammatory cytokines modulated by NF-κB signaling were effectively down-regulated both in vivo and in vitro, as determined by immunohistochemistry and ELISA. In conclusion, these results indicate that GC possesses a beneficial effect against MI/R injury via inflammation inhibition that may involve suppression of CD40-NF-κB signal pathway and downstream inflammatory cytokines expression, which may offer an alternative medication for MI/R diseases.