Receptor proximal kinases in NF-κB signaling as potential therapeutic targets in cancer and inflammation

A SARS-CoV-2-specific CAR-T-cell model identifies felodipine, fasudil, imatinib, and caspofungin as potential treatments for lethal COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced cytokine storm is closely associated with coronavirus disease 2019 (COVID-19) severity and lethality. However, drugs that are effective against inflammation to treat lethal COVID-19 are still urgently needed. Here, we constructed a SARS-CoV-2 spike protein-specific CAR, and human T cells infected with this CAR (SARS-CoV-2-S CAR-T) and stimulated with spike protein mimicked the T-cell responses seen in COVID-19 patients, causing cytokine storm and displaying a distinct memory, exhausted, and regulatory T-cell phenotype. THP1 remarkably augmented cytokine release in SARS-CoV-2-S CAR-T cells when they were in coculture. Based on this "two-cell" (CAR-T and THP1 cells) model, we screened an FDA-approved drug library and found that felodipine, fasudil, imatinib, and caspofungin were effective in suppressing the release of cytokines, which was likely due to their ability to suppress the NF-κB pathway in vitro. Felodipine, fasudil, imatinib, and caspofungin were further demonstrated, although to different extents, to attenuate lethal inflammation, ameliorate severe pneumonia, and prevent mortality in a SARS-CoV-2-infected Syrian hamster model, which were also linked to their suppressive role in inflammation. In summary, we established a SARS-CoV-2-specific CAR-T-cell model that can be utilized as a tool for anti-inflammatory drug screening in a fast and high-throughput manner. The drugs identified herein have great potential for early treatment to prevent COVID-19 patients from cytokine storm-induced lethality in the clinic because they are safe, inexpensive, and easily accessible for immediate use in most countries.

Targeting p65 to inhibit Cas3 transcription by Onjisaponin B for radiation damage therapy in p65+/- mice

BACKGROUND

In response to radiation injury, p65 becomes activated. The formation of p65 is one target of Onjisaponin B (OB), but it has not been studied in radioprotection. In addition, there is a binding site for p65 in the promoter region of Cas3. This study evaluates the use of OB as an intervention to modulate p65/Cas3 following radiation exposure.

PURPOSE

This study aimed to confirm that OB regulated the transcription of Cas3 via p65 to overcome radiation-induced damage.

STUDY DESIGN AND METHODS

Cells and mice were exposed to X-rays at a dose of 6 Gy. Immunofluorescence was used to locate intracellular p65. For the protein and mRNA analyses, Western blotting and RT-qPCR-based assays were conducted accordingly. HE staining was used to observe pathological changes in tissues. DNA damage was detected by the comet assay and DNA ladder assay. Next, apoptosis was detected by flow cytometry and Hoechst staining.

RESULTS

Compared with the radiation group, the expression levels of p-p65 and c-Cas3 in the drug group were significantly down-regulated by OB 20 µg/ml. When the expression of p65 was suppressed in V79 and TC cells, OB did not significantly inhibit the activation of p65 or Cas3 in response to irradiation, nor did it significantly inhibit the phosphorylation of p65 and subsequent nuclear translocation. Overexpression of p65 in V79 and MTEC-1 cells resulted in OB significantly inhibiting the activation of p65 and Cas3, and the phosphorylation and translocation of p65 into the nucleus. At 3 d for V79 cells and 24 h for MTEC-1 cells after radiation, compared with the Cas3 over plasmid transfection group, the drug transfection group had no significant effect on reducing apoptosis. In p65+/- mice, expression of the p65 gene was knocked down, leading to increased tissue apoptosis and inflammation, and serious tissue pathological changes. The inhibition of p65 activation by OB after radiation exposure was not apparent in the thymus, although it was observed in the lung.

CONCLUSIONS

OB interfered with radiation injury by targeting and regulating p65/Cas3. Therefore, it has been concluded that p65 is an important target molecule for the treatment of radiation injury.

Anti-inflammatory effect of resveratrol attenuates the severity of diabetic neuropathy by activating the Nrf2 pathway

The mechanisms underlying the development of neuropathy associated with diabetes mellitus are not fully understood. Resveratrol, as a nonflavonoid polyphenol, plays a variety of beneficial roles in the treatment of chronic diseases such as Alzheimer's disease, coronary heart disease and obesity. In our study, the role of nuclear erythroid 2-related factor 2 (Nrf2) in resveratrol-mediated protection against streptozotocin-induced diabetic peripheral neuropathy (DPN) was investigated, and the antioxidant effect of resveratrol in diabetic peripheral nerves was studied. The STZ-treated model mice were divided into two groups. The resveratrol group was intragastrically administered 10 ml/kg 10% resveratrol once a day until the 12th week after STZ injection. The vehicle-treated mice were injected with the same volume of DMSO. Analysis of the effects of resveratrol in DPN revealed the following novel findings: (i) the pain and temperature sensitivities of diabetic mice were improved after treatment with resveratrol; (ii) Nrf2 expression was increased in the diabetic peripheral nerves of resveratrol-treated mice, and NF-KB pathway inhibition protected nerves upon resveratrol treatment in peripheral neuropathy; and (iii) resveratrol modulated the anti-inflammatory microenvironment of peripheral nerves by increasing Nrf2 activation and the expression of p-p65, and these changes may have been responsible for the neuroprotective effect of resveratrol in DPN, which was confirmed by Nrf2 knockout in diabetic mice. Overall, this study demonstrates that resveratrol may attenuate the severity of DPN by protecting peripheral nerves from apoptosis by inhibiting the NF-KB pathway and increasing Nrf2 expression.

Dominant-negative NFKBIA mutation promotes IL-1β production causing hepatic disease with severe immunodeficiency

Although IKK-β has previously been shown as a negative regulator of IL-1β secretion in mice, this role has not been proven in humans. Genetic studies of NF-κB signaling in humans with inherited diseases of the immune system have not demonstrated the relevance of the NF-κB pathway in suppressing IL-1β expression. Here, we report an infant with a clinical pathology comprising neutrophil-mediated autoinflammation and recurrent bacterial infections. Whole-exome sequencing revealed a de novo heterozygous missense mutation of NFKBIA, resulting in a L34P IκBα variant that severely repressed NF-κB activation and downstream cytokine production. Paradoxically, IL-1β secretion was elevated in the patient's stimulated leukocytes, in her induced pluripotent stem cell-derived macrophages, and in murine bone marrow-derived macrophages containing the L34P mutation. The patient's hypersecretion of IL-1β correlated with activated neutrophilia and liver fibrosis with neutrophil accumulation. Hematopoietic stem cell transplantation reversed neutrophilia, restored a resting state in neutrophils, and normalized IL-1β release from stimulated leukocytes. Additional therapeutic blockade of IL-1 ameliorated liver damage, while decreasing neutrophil activation and associated IL-1β secretion. Our studies reveal a previously unrecognized role of human IκBα as an essential regulator of canonical NF-κB signaling in the prevention of neutrophil-dependent autoinflammatory diseases. These findings also highlight the therapeutic potential of IL-1 inhibitors in treating complications arising from systemic NF-κB inhibition.

LncRNA-MAP3K4 regulates vascular inflammation through the p38 MAPK signaling pathway and cis-modulation of MAP3K4

Chronic vascular inflammation plays a key role in the pathogenesis of atherosclerosis. Long non-coding RNAs (lncRNAs) have emerged as essential inflammation regulators. We identify a novel lncRNA termed lncRNA-MAP3K4 that is enriched in the vessel wall and regulates vascular inflammation. In the aortic intima, lncRNA-MAP3K4 expression was reduced by 50% during the progression of atherosclerosis (chronic inflammation) and 70% during endotoxemia (acute inflammation). lncRNA-MAP3K4 knockdown reduced the expression of key inflammatory factors (eg, ICAM-1, E-selectin, MCP-1) in endothelial cells or vascular smooth muscle cells and decreased monocytes adhesion to endothelium, as well as reducing TNF-α, IL-1β, COX2 expression in macrophages. Mechanistically, lncRNA-MAP3K4 regulates inflammation through the p38 MAPK signaling pathway. lncRNA-MAP3K4 shares a bidirectional promoter with MAP3K4, an upstream regulator of the MAPK signaling pathway, and regulates its transcription in cis. lncRNA-MAP3K4 and MAP3K4 show coordinated expression in response to inflammation in vivo and in vitro. Similar to lncRNA-MAP3K4, MAP3K4 knockdown reduced the expression of inflammatory factors in several different vascular cells. Furthermore, lncRNA-MAP3K4 and MAP3K4 knockdown showed cooperativity in reducing inflammation in endothelial cells. Collectively, these findings unveil the role of a novel lncRNA in vascular inflammation by cis-regulating MAP3K4 via a p38 MAPK pathway.

Mutual regulation of metabolic processes and proinflammatory NF-κB signaling

The nuclear factor kappa B (NF-κB) signaling system, a key regulator of immunologic processes, also affects a plethora of metabolic changes associated with inflammation and the immune response. NF-κB-regulating signaling cascades, in concert with NF-κB-mediated transcriptional events, control the metabolism at several levels. NF-κB modulates apical components of metabolic processes including metabolic hormones such as insulin and glucagon, the cellular master switches 5' AMP-activated protein kinase and mTOR, and also numerous metabolic enzymes and their respective regulators. Vice versa, metabolic enzymes and their products also exert multilevel control of NF-κB activity, thereby creating a highly connected regulatory network. These insights have resulted in the identification of the noncanonical IκB kinase kinases IκB kinase ɛ and TBK1, which are upregulated by overnutrition, and may therefore be suitable potential therapeutic targets for metabolic syndromes. An inhibitor interfering with the activity of both kinases reduces obesity-related metabolic dysfunctions in mouse models and the encouraging results from a recent clinical trial indicate that targeting these NF-κB pathway components improves glucose homeostasis in a subset of patients with type 2 diabetes.

IKKβ Inhibitor IMD-0354 Attenuates Radiation Damage in Whole-body X-Irradiated Mice

Nuclear factor-kappa B (NF-κB) transcription factor plays a critical role in regulating radiation-induced inflammatory and immune responses. Intracellular reactive oxygen species generation induces the activation of NF-κB via the inhibitor of κB (IκB) kinase (IKK) complex signaling. Previous studies have reported that the inhibition of IKK-driven NF-κB activation offers a therapeutic strategy for managing inflammatory disorders and various cancers, but it has additionally been reported that treatment targeting NF-κB also shows a radioprotective effect. IMD-0354 is an IKKβ inhibitor that blocks IκBα phosphorylation in the NF-κB pathway. This compound is known to exert anti-inflammatory and antitumor effects, but its radioprotective effects are unclear. Therefore, in the present study, we examined whether or not IMD-0354 has a mitigative effect on radiation-induced damages in mice. IMD-0354 was dissolved in soybean oil and subcutaneously administered to C57BL/6J Jcl mice for 3 consecutive days after 7 Gy of whole-body X-irradiation. The survival rate on day 30 and the NF-κB p65 and IκBα in bone marrow and spleen cells based on flow cytometry were assessed. IMD-0354 administration significantly suppressed the lethality induced by whole-body X-irradiation, and the survival rate increased by 83%. The NF-κB p65 and IκBα in bone marrow and spleen cells were significantly lower in IMD-0354-treated mice than in irradiated mice, suggesting that the IKKβ inhibitor IMD-0354 exerts a radiomitigative effect by suppressing the NF-κB.

The intricate role of miR-155 in carcinogenesis: potential implications for esophageal cancer research

MiRNAs have immerged as essential modulators of key cellular procuresses involved in post-transcriptional regulation of the human transcriptome. They are essential components of complex regulatory networks that modulate most important physiological functions of cells. MicroRNA-155 (miR-155) is a multifaceted regulator of cell proliferation, cell cycle, development, immunity and inflammation that plays pivotal, and sometimes contradictory, roles in numerous cancers including esophageal cancer. Here, we review the intricate role of miR-155 in cancer by exemplifying carcinogenesis of various tumors, focusing on recent findings that may provide a link between miR-155 and esophageal cancer-related pathways.

TBL1XR1 mutations in Pierpont syndrome are not restricted to the recurrent p.Tyr446Cys mutation

Pierpont syndrome is a rare and sporadic syndrome, including developmental delay, facial characteristics, and abnormal extremities. Recently, a recurrent de novo TBL1XR1 variant (c.1337A > G; p.Tyr446Cys) has been identified in eight patients by whole-exome sequencing. A dominant-negative effect of this mutation is strongly suspected, since patients with TBL1XR1 deletion and other variants predicting loss of function do not share the same phenotype. We report two patients with typical Pierpont-like syndrome features. Exome sequencing allowed identifying a de novo heterozygous missense TBL1XR1 variant in both patients, different from those already reported: p.Cys325Tyr and p.Tyr446His. The localization of these mutations and clinical features of Pierpont-like syndrome suggest that their functional consequences are comparable with the recurrent mutation previously described, and provided additional data to understand molecular mechanisms of TBL1XR1 anomalies.

Targeting IKKβ in Cancer: Challenges and Opportunities for the Therapeutic Utilisation of IKKβ Inhibitors

Deregulated NF-κB signalling is implicated in the pathogenesis of numerous human inflammatory disorders and malignancies. Consequently, the NF-κB pathway has attracted attention as an attractive therapeutic target for drug discovery. As the primary, druggable mediator of canonical NF-κB signalling the IKKβ protein kinase has been the historical focus of drug development pipelines. Thousands of compounds with activity against IKKβ have been characterised, with many demonstrating promising efficacy in pre-clinical models of cancer and inflammatory disease. However, severe on-target toxicities and other safety concerns associated with systemic IKKβ inhibition have thus far prevented the clinical approval of any IKKβ inhibitors. This review will discuss the potential reasons for the lack of clinical success of IKKβ inhibitors to date, the challenges associated with their therapeutic use, realistic opportunities for their future utilisation, and the alternative strategies to inhibit NF-κB signalling that may overcome some of the limitations associated with IKKβ inhibition.

Exploring the molecular pathogenesis associated with T-cell prolymphocytic leukemia based on a comprehensive bioinformatics analysis

As a rare hematological malignancy, T-cell prolymphocytic leukemia (T-PLL) has a high mortality rate. However, the comprehensive mechanisms of the underlying pathogenesis of T-PLL are unknown. The purpose of the present study was to investigate the pathogenesis of T-PLL based on a comprehensive bioinformatics analysis. The differentially expressed genes (DEGs) between T-PLL blood cell samples and normal peripheral blood cell samples were investigated using the GSE5788 Affymetrix microarray data from the Gene Expression Omnibus database. To investigate the functional changes associated with tumor progression, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were used on the identified DEGs, followed by protein-protein interaction (PPI) and sub-PPI analysis. Transcription factors and tumor-associated genes (TAGs) were investigated further. The results identified 84 upregulated genes and 354 downregulated genes in T-PLL samples when compared with healthy samples. These DEGs featured in various functions including cell death and various pathways including apoptosis. The functional analysis of DEGs revealed 17 dysregulated transcription factors and 37 dysregulated TAGs. Furthermore, the PPI network analysis based on node degree (a network topology attribute) identified 61 genes, including the core downregulated gene of the sub-PPI network, signal transducer and activator of transcription 3 (STAT3; degree, 13) and the core upregulated gene, insulin receptor substrate-1 (IRS1; degree, 5), that may have important associations with the progression of T-PLL. Alterations to cell functions, including cell death, and pathways, including apoptosis, may contribute to the process of T-PLL. Candidate genes identified in the present study, including STAT3 and IRS1, should be targets for additional studies.

Effects of a novel microtubule-depolymerizer on pro-inflammatory signaling in RAW264.7 macrophages

The Nuclear Factor-kappa B (NF-κB) pathway is vital for immune system regulation and pro-inflammatory signaling. Many inflammatory disorders and diseases, including cancer, are linked to dysregulation of NF-κB signaling. When macrophages recognize the presence of a pathogen, the signaling pathway is activated, resulting in the nuclear translocation of the transcription factor, NF-κB, to turn on pro-inflammatory genes. Here, we demonstrate the effects of a novel microtubule depolymerizer, NT-07-16, a polysubstituted pyrrole compound, on this process. Treatment with NT-07-16 decreased the production of pro-inflammatory cytokines in RAW264.7 mouse macrophages. It appears that the reduction in pro-inflammatory mediators produced by the macrophages after exposure to NT-07-16 may be due to activities upstream of the translocation of NF-κB into the nucleus. NF-κB translocation occurs after its inhibitory protein, IκB-α is phosphorylated which signals for its degradation releasing NF-κB so it is free to move into the nucleus. Previous studies from other laboratories indicate that these processes are associated with the microtubule network. Our results show that exposure to the microtubule-depolymerizer, NT-07-16 reduces the phosphorylation of IκB-α and also decreases the association of NF-κB with tubulin which may affect the ability of NF-κB to translocate into the nucleus. Therefore, the anti-inflammatory activity of NT-07-16 may be explained, at least in part, by alterations in these steps in the NF-κB signaling pathway leading to less NF-κB entering the nucleus and reducing the production of pro-inflammatory mediators by the activated macrophages.

Molecular chemotherapeutic potential of butein: A concise review

Butein is a biologically active flavonoid isolated from the bark of Rhus verniciflua Stokes, which is known to have therapeutic potential against various cancers. Notably, butein inhibits cancer cell growth by inducing G₂/M phase arrest and apoptosis. Butein-induced G₂/M phase arrest is associated with increased phosphorylation of ataxia telangiectasia mutated (ATM) and Chk1/2, and consequently, with reduced cdc25C levels. In addition, butein-induced apoptosis is mediated through the activation of caspase-3, which is associated with changes in the expression of Bcl-2 and Bax proteins. Intriguingly, butein sensitizes cells to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis via ERK-mediated Sp1 activation, which promotes the transcription of specific death receptor 5. Butein also inhibits the migration and invasion of human cancer cells by suppressing nuclear factor-κB- and extracellular signal-regulated kinases 1/2-mediated expression of matrix metalloproteinase-9 and vascular endothelial growth factor. Additionally, butein downregulates the expression of human telomerase reverse transcriptase and causes a concomitant decrease in telomerase activity. These findings provide the basis for the pharmaceutical development of butein. The aim of this review is to provide an update on the mechanisms underlying the anticancer activity of butein, with a special focus on its effects on different cellular signaling cascades.

IκB-kinase-ε in the tumor microenvironment is essential for the progression of gastric cancer

The tumor microenvironment is critical for tumor growth and metastasis, but the underlying molecular mechanisms are poorly understood. Recent studies have shown that IκB-kinase-ε (IKKε) is involved in the proliferation and migration of certain cancers. However, the functional role of IKKε in the progression of gastric cancer (GC) remains unknown. In this study, we found that high levels of IKKε expression in GC tumors were correlated with more advanced disease and poor overall survival of patients. Silencing of IKKε effectively suppressed the migratory and invasive capabilities of human GC cells in vitro and tumorigenicity and metastasis in vivo. Further analysis revealed that IKKε was also highly expressed in tumor-infiltrating lymphocytes. Moreover, it was involved in tumor-infiltrating T-cell-mediated invasion and metastasis. Knockdown of IKKε elevated T-cell antitumor immunity. These findings suggest that IKKε may be a novel prognostic marker and a potential therapeutic target in human GCs.

Inhibitory effect and mechanism of mesenchymal stem cells on melanoma cells

PURPOSE

To explore the inhibitory effect and mechanism of MSCs on melanoma proliferation.

METHODS

The inhibitory effect of MSCs on melanoma A375 cells was detected by co-culture and conditioned medium (CM) experiments using MTT method. The cell cycle was analyzed by flow cytometry. Then, Western Blot experiment detected the expression of proteins related to NF-κB signaling in A375 cells. The expression of IL-1Ra in MSCs was proved by RT-PCR. The over-expression and silencing vector pcDNA3.1-EGFP-IL-1Ra and pGPH1-IL-1R were constructed and transfected into MSCs cells. After that, the changes of inhibitory effect and cell cycle from MSCs-S and MSCs-O CM on A375 cells were explored. The expression of proteins related to NF-κB signaling in A375 cells after MSCs-S or MSCs-O CM treatment was detected by Western Blot. MSCs, MSCs-S, or MSCs-O and A375 cells were co-injected into nude mice under the arms, the growth of tumor was observed, the frozen sections were made, and H&E staining of tumor tissue was performed.

RESULTS

The proliferation of A375 cells was inhibited and the cell cycle of A375 was arrested by MSCs. The expressions of cytokines related to NF-κB signaling were down-regulated. Over-expression and silence of Interleukin 1 receptor antagonist (IL-1Ra), specifically blocking activation of NF-κB signaling, indicated that inhibitory effect from MSCs was enhanced or weakened respectively, which suggested that IL-1Ra was involved in the inhibitory effect. In vivo, tumor initiation and growth were significantly inhibited when A375 cells were co-injected with MSCs into nude mice, which were related to the expression level of IL-1Ra.

CONCLUSION

MSCs could inhibit the proliferation and tumor initiation of melanoma A375 cells through NF-κB signaling. MSCs could secret IL-1Ra and inhibit expressions of NF-κB signaling-related factors of tumor cells, and cause cell cycle arrest in G1 phase.

NF-κB in Hematological Malignancies

NF-κB (Nuclear Factor Κ-light-chain-enhancer of activated B cells) transcription factors are critical regulators of immunity, stress response, apoptosis, and differentiation. Molecular defects promoting the constitutive activation of canonical and non-canonical NF-κB signaling pathways contribute to many diseases, including cancer, diabetes, chronic inflammation, and autoimmunity. In the present review, we focus our attention on the mechanisms of NF-κB deregulation in hematological malignancies. Key positive regulators of NF-κB signaling can act as oncogenes that are often prone to chromosomal translocation, amplifications, or activating mutations. Negative regulators of NF-κB have tumor suppressor functions, and are frequently inactivated either by genomic deletions or point mutations. NF-κB activation in tumoral cells is also driven by the microenvironment or chronic signaling that does not rely on genetic alterations.

First Bispecific Inhibitors of the Epidermal Growth Factor Receptor Kinase and the NF-κB Activity As Novel Anticancer Agents

The activation of the NF-κB transcription factor is a major adaptive response induced upon treatment with EGFR kinase inhibitors, leading to the emergence of resistance in nonsmall cell lung cancer and other tumor types. To suppress this survival mechanism, we developed new thiourea quinazoline derivatives that are dual inhibitors of both EGFR kinase and the NF-κB activity. Optimization of the hit compound, identified in a NF-κB reporter gene assay, led to compound 9b, exhibiting a cellular IC₅₀ for NF-κB inhibition of 0.3 μM while retaining a potent EGFR kinase inhibition (IC₅₀ = 60 nM). The dual inhibitors showed a higher potency than gefitinib to inhibit cell growth of EGFR-overexpressing tumor cell lines in vitro and in a xenograft model in vivo, while no signs of toxicity were observed. An investigation of the molecular mechanism of NF-κB suppression revealed that the dual inhibitors depleted the transcriptional coactivator CREB-binding protein from the NF-κB complex in the nucleus.

Identification of Candidate Genes Related to Inflammatory Bowel Disease Using Minimum Redundancy Maximum Relevance, Incremental Feature Selection, and the Shortest-Path Approach

Identification of disease genes is a hot topic in biomedicine and genomics. However, it is a challenging problem because of the complexity of diseases. Inflammatory bowel disease (IBD) is an idiopathic disease caused by a dysregulated immune response to host intestinal microflora. It has been proven to be associated with the development of intestinal malignancies. Although the specific pathological characteristics and genetic background of IBD have been partially revealed, it is still an overdetermined disease and the blueprint of all genetic variants still needs to be improved. In this study, a novel computational method was built to identify genes related to IBD. Samples from two subtypes of IBD (ulcerative colitis and Crohn's disease) and normal samples were employed. By analyzing the gene expression profiles of these samples using minimum redundancy maximum relevance and incremental feature selection, 21 genes were obtained that could effectively distinguish samples from the two subtypes of IBD and the normal samples. Then, the shortest-path approach was used to search for an additional 20 genes in a large network constructed using protein-protein interactions based on the above-mentioned 21 genes. Analyses of the 41 genes obtained indicate that they are closely associated with this disease.

Characterization of the in vitro effects of gallic acid-grafted-chitooligosaccharides in the suppression of AGS human gastric cancer cell proliferation

G-COS was compared with COS for its influence on the proliferation of AGS human gastric cancer cells, showing an increase in the accumulation of cells in the sub-G1 phase and early apoptosis.

TGR5, Not Only a Metabolic Regulator

G-protein-coupled bile acid receptor, Gpbar1 (TGR5), is a member of G-protein-coupled receptor (GPCR) superfamily. High levels of TGR5 mRNA were detected in several tissues such as small intestine, stomach, liver, lung, especially in placenta and spleen. TGR5 is not only the receptor for bile acids, but also the receptor for multiple selective synthetic agonists such as 6α-ethyl-23(S)-methyl-cholic acid (6-EMCA, INT-777) and a series of 4-benzofuranyloxynicotinamde derivatives to regulate different signaling pathways such as nuclear factor κB (NF-κB), AKT, and extracellular signal-regulated kinases (ERK). TGR5, as a metabolic regulator, is involved in energy homeostasis, bile acid homeostasis, as well as glucose metabolism. More recently, our group and others have extended the functions of TGR5 to more than metabolic regulation, which include inflammatory response, cancer and liver regeneration. These findings highlight TGR5 as a potential drug target for different diseases. This review summarizes the basic information of TGR5 and its new functions.

Suberoylanilide Hydroxamic Acid, an Inhibitor of Histone Deacetylase, Induces Apoptosis in Rheumatoid Arthritis Fibroblast-Like Synoviocytes

Here, we explored the effects of suberoylanilide hydroxamic acid (SAHA) on the viability and apoptosis of rheumatoid arthritis of fibroblast-like synoviocytes (rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS)). FLS obtained from RA patients were treated with SAHA. SAHA significantly inhibited the viability of RA FLS in a concentration-dependent manner up to 5 μM. SAHA-treated FLS showed a significant increase in the percentage of apoptosis and the expression and activity of caspase-3 and higher intracellular ROS levels. N-acetyl-l-cysteine (NAC) pretreatment significantly attenuated SAHA-induced apoptosis, decreasing the percentage of apoptosis by about 60 %. A significant decline in phosphorylated IκBα and nuclear factor kappa B (NF-κB) p65 and concomitant increase in total IκBα were shown in SAHA-treated FLS. Additionally, the levels of anti-apoptotic Bcl-2 proteins (Bcl-xL and Mcl-1) were significantly reduced by SAHA. Collectively, SAHA induces apoptosis of RA FLS, at least partially, through generation of ROS and suppression of NF-κB activation and Bcl-xL and Mcl-1 expression.

Aqueous synthesized quantum dots interfere with the NF-κB pathway and confer anti-tumor, anti-viral and anti-inflammatory effects

The NF-κB pathway plays crucial roles in inflammatory responses and cell survival. Aberrant constitutive NF-κB activation is associated with various human diseases including cancer and inflammatory and auto-immune diseases. Consequently, it is highly desirable to develop new kinds of inhibitors, which are highly efficacious for blocking the NF-κB pathway. In this study, by using a typical kind of aqueous synthesized quantum dots (QDs), i.e., CdTe QDs, as a model, we for the first time demonstrated that the QDs could selectively affect the cellular nuclear factor-κB (NF-κB) signaling pathway, but do not affect the AKT or ERK pathways. Typically, the QDs efficiently inhibited the activation of IKKα and IKKβ, resulting in the suppression of both the canonical and the non-canonical NF-κB signaling pathways. Inhibition of NF-κB by QDs downregulates anti-apoptotic genes and promotes apoptosis in cancer cells. The QDs induced NF-κB inhibition and cytotoxicity could be blocked by N-acetylcysteine due to the reduced cellular uptake of QDs. Importantly, inhibition of NF-κB by QDs displayed promising effects against the viral replication and in vivo bacterial endotoxin-induced inflammatory responses. These data suggest the QDs as potent inhibitors of the NF-κB signaling pathway, both in vitro and in vivo. Our findings highlight the potential of using QDs in the development of anti-cancer, anti-viral, and anti-inflammatory approaches, and also facilitate better understanding of QDs-related cellular behavior under the molecular level.

NF-κB signaling as a driver of ageing

NF-κB signaling exerts essential roles in immunity and cellular stress responses, regulating many functions related with organism innate defense. Besides, NF-κB altered signaling has been causally linked to ageing and diverse pathological conditions. We discuss herein the functional involvement of this signaling pathway in ageing, visiting recent experimental evidence about NF-κB activation in this complex process, its functional consequences and the novel biological functions raised from these works. Moreover, we discuss ageing intervention strategies based on NF-κB inhibition, which have demonstrated to be effective at delaying and even reverting different ageing manifestations in human and mouse models of both normal and accelerated ageing. Altogether, the current evidence supports that NF-κB activation constitutes a driving force of the ageing process and a preferential target for rejuvenation-aimed approaches.

GABAB R/GSK-3β/NF-κB signaling pathway regulates the proliferation of colorectal cancer cells

Colorectal cancer is one of the leading causes of highly fatal cancer-related deaths in the whole world. Fast growth is critical characteristic of colorectal cancer, the underlying regulatory mechanism of colorectal cell fast proliferation remains largely unknown. Here, we reported that activation of metabotropic γ-Aminobutyric acid receptor (GABAB R) signaling significantly inhibited the colorectal cell HT29 proliferation by arresting the cell at G1 phase. Inhibition of GABAB R activated GSK-3β by reducing the phosphorylation level of GSK-3β. Activation of GSK-3β blocked the function of GABAB R signaling on repressing cell proliferation. We further found that GABAB R activation inhibited NF-κB activity. The promotion of cell proliferation caused by downregulation of GABRB R could be blocked by inhibition of NF-κB activation. Overall, activation of GABAB R leaded to inhibition of GSK-3β activation to repress the NF-κB function during colorectal cancer cell proliferation. This study revealed critical function of GABAB R/GSK-3β/NF-κB signaling pathway on regulating proliferation of colorectal cancer cell, which might provide a potential therapeutic target for clinical colorectal cancer treatment.

Drugs from nature targeting inflammation (DNTI): a successful Austrian interdisciplinary network project

ABSTRACT

Inflammation is part of numerous pathological conditions, which are lacking satisfying treatment and effective concepts of prevention. A national research network project, DNTI, involving scientists from six Austrian universities as well as several external partners aimed to identify and characterize natural products capable of combating inflammatory processes specifically in the cardiovascular system. The combined use of computational techniques with traditional knowledge, high-tech chemical analysis and synthesis, and a broad range of in vitro, cell-based, and in vivo pharmacological models led to the identification of a series of promising anti-inflammatory drug lead candidates. Mechanistic studies contributed to a better understanding of their mechanism of action and delivered new knowledge on the molecular level of inflammatory processes. Herein, the used approaches and selected highlights of the results of this interdisciplinary project are presented.

GRAPHICAL ABSTRACT

Effects of a pyrrole-based, microtubule-depolymerizing compound on RAW 264.7 macrophages

RAW 264.7 murine macrophages were exposed to the pyrrole-based compound 3,5-Dibromo-4-(3,4-dimethoxyphenyl)-1H-pyrrole-2-carboxylic acid ethyl ester (JG-03-14), which is a known microtubule depolymerizing agent with antitumor activity [1,2,3]. In this study exposure to JG-03-14 reduced the production of pro-inflammatory molecules by macrophages activated with lipopolysaccharide (LPS). Treatment with the pyrrole-based compound decreased the concentration of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) released from the macrophages. Exposure to JG-03-14 also decreased TNF-α mRNA expression levels and the protein expression levels of inducible nitric oxide synthase (iNOS), the enzyme responsible for NO production in the activated macrophages. Furthermore, JG-03-14 treatment significantly changed the degradation profile of IκB-β, an inhibitor of the NF-κB transcription factor, which suggests that JG-03-14 may attenuate the activation of the LPS-induced NF-κB signaling pathway needed to produce the pro-inflammatory mediators. We conclude that JG-03-14 possesses anti-inflammatory properties.

Killing cancer with platycodin D through multiple mechanisms

Cancer is a multi-faceted disease comprised of a combination of genetic, epigenetic, metabolic and signalling aberrations which severely disrupt the normal homoeostasis of cell growth and death. Rational developments of highly selective drugs which specifically block only one of the signalling pathways have been associated with limited therapeutic success. Multi-targeted prevention of cancer has emerged as a new paradigm for effective anti-cancer treatment. Platycodin D, a triterpenoid saponin, is one the major active components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties including, anti-nociceptive, anti-atherosclerosis, antiviral, anti-inflammatory, anti-obesity, immunoregulatory, hepatoprotective and anti-tumour activities. Recently, the anti-cancer activity of platycodin D has been extensively studied. The purpose of this review was to give our perspectives on the current status of platycodin D and discuss its anti-cancer activity and molecular mechanisms which may help the further design and conduct of pre-clinical and clinical trials to develop it successfully into a potential lead drug for oncological therapy. Platycodin D has been shown to fight cancer by inducing apoptosis, cell cycle arrest, and autophagy and inhibiting angiogenesis, invasion and metastasis by targeting multiple signalling pathways which are frequently deregulated in cancers suggesting that this multi-target activity rather than a single effect may play an important role in developing platycodin D into potential anti-cancer drug.

Modulation of NF-κB Signaling as a Therapeutic Target in Autoimmunity

Autoimmune diseases arise from the loss of tolerance to endogenous self-antigens, resulting in a heterogeneous range of chronic conditions that cause considerable morbidity and mortality worldwide. In Western countries, over 5% of the population is affected by some form of autoimmune disease, with enhanced or inappropriate activation of nuclear factor (NF)-κB implicated in a number of these conditions. Although treatment strategies for autoimmunity have improved significantly in recent years, current therapeutics are still not capable of achieving satisfactory disease management in all patients, and as such, the therapeutic modulation of NF-κB is an attractive target in autoimmunity. To date, no NF-κB inhibitors have progressed to the clinic for the treatment of autoimmunity, but a variety of promising approaches targeting multiple stages of the NF-κB pathway are currently being explored. This review focuses on the current strategies being investigated for the inhibition of the NF-κB pathway in autoimmune diseases and considers potential future strategies for the therapeutic targeting of this crucial transcription factor.

Isoliensinine, a Bioactive Alkaloid Derived from Embryos of Nelumbo nucifera, Induces Hepatocellular Carcinoma Cell Apoptosis through Suppression of NF-κB Signaling

Isoliensinine (isolie) is an alkaloid produced by the edible plant Nelumbo nucifera. Here, we unveiled that isolie was able to provoke HepG2, Huh-7, and H22 hepatocellular carcinoma (HCC) cell apoptosis. Isolie decreased NF-κB activity and constitutive phosphorylation of NF-κB p65 subunit at Ser536 in HCC cells. Overexpression of p65 Ser536 phosphorylation mimics abrogated isolie-mediated HCC cell apoptosis. Furthermore, intraperitoneal injection of isolie inhibited the growth of Huh-7 xenografts in nude mice. Additionally, isolie given by both intraperitoneal injection and gavage diminished the proliferation of transplanted H22 cells in Kunming mice. Reduced tumor growth in vivo was associated with inhibited p65 phosphorylation at Ser536 and declined NF-κB activity in tumor tissues. Finally, we revealed that isolie was bioavailable in the blood of mice and exhibited no detectable toxic effects on tumor-bearing mice. Our data provided strong evidence for the anti-HCC effect of isolie.

Tungsten Carbide-Cobalt Nanoparticles Induce Reactive Oxygen Species, AKT, ERK, AP-1, NF-κB, VEGF, and Angiogenesis

Powder mixtures of tungsten carbide and metallic cobalt (WC-Co) are widely used in various products. Nanoparticles are engineered structures with at least one dimension of 100 nm or smaller. WC-Co is known to be associated with lung injury and diseases. Angiogenesis is a key process during vasculature, carcinogenesis, recovery of injury, and inflammatory diseases. However, the cellular effects of WC-Co nanoparticles on angiogenesis remain to be elucidated. In this study, we investigated angiogenic response and relative mechanisms after exposure to WC-Co nanoparticles. Our results showed that WC-Co nanoparticles at 5 μg/cm(2) induced ROS production which activated AKT and ERK1/2 signaling pathways in lung epithelial cells by reactive oxygen species (ROS) staining and immunoblotting; WC-Co treatment also increased transcriptional activation of AP-1, NF-κB, and VEGF by reporter assay. Further studies demonstrated that ROS are upstream molecules of AKT and ERK signaling pathways; the activation of AP-1, NF-κB, and VEGF was through ROS generation, AKT and ERK1/2 activation. In addition, WC-Co nanoparticles affected the cells to induce angiogenesis by chicken chorioallantoic membrane (CAM) assay. These results illustrate that exposure to WC-Co nanoparticles induces angiogenic response by activating ROS, AKT, and ERK1/2 signaling pathways and the downstream molecules and elucidate the potential molecular mechanisms during this process. This information may be useful for preventing potential damage from nanoparticle exposure in the future.

Camptothecin suppresses expression of matrix metalloproteinase-9 and vascular endothelial growth factor in DU145 cells through PI3K/Akt-mediated inhibition of NF-κB activity and Nrf2-dependent induction of HO-1 expression

Though camptothecin (CPT) possesses potent anti-inflammatory, immunomodulatory, anticancerous, and antiproliferative effects, little is known about the mechanism by which CPT regulates the expression of matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF). Therefore, the current study aimed to investigate the effects of CPT on the expression of MMP-9 and VEGF, which are important factors for the invasion of tumors. In vitro application of CPT resulted in a slight inhibition of cell proliferation and a significant reduction in the matrigel invasion of DU145 cells. Treatment with CPT also downregulated phorbol-12-myristate-13-acetate (PMA)- and tumor necrosis factor-α (TNF-α)-induced MMP-9 and VEGF expression by inhibiting nuclear factor-κB (NF-κB) activity. Downregulation of phosphoinositide 3-kinase (PI3K)/Akt phosphorylation in response to CPT was revealed as an upstream pathway regulating the expression of MMP-9 and VEGF accompanying the inhibition of NF-κB activity. We further confirmed that CPT inhibits PMA-induced MMP-9 and VEGF expression by upregulating nuclear factor-erythroid related factor-2 (Nrf2)-mediated heme oxygenase-1 (HO-1) induction. Taken together, these data indicate that CPT inhibits the invasion of cancer cells accompanied by suppression of MMP-9 and VEGF production by suppressing the PI3K/Akt-mediated NF-κB pathway and enhancing the Nrf2-dependent HO-1 pathway, suggesting that CPT may be a good candidate to inhibit MMP-9 and VEGF expression.