We have isolated two Drosophila lines that carry point mutations in the gene coding for the NF-KB-like factor DIF. Like mutants of the Toll pathway, Dif mutant flies are susceptible to fungal but not to bacterial infections. Genetic epistasis experiments demonstrate that Dif mediates the Toll-dependent control of the inducibility of the antifungal peptide gene Drosomycin. Strikingly, DIF alone is required for the antifungal response in adults, but is redundant in larvae with Dorsal, another Rel family member. In Drosophila, Dif appears to be dedicated to the antifungal defense elicited by fungi and gram-positive bacteria. We discuss in this light the possibility that NF-KB1/p50 might be required more specifically in the innate immune response against gram-positive bacteria in mammals.

Addiction occurs through repeated abuse of drugs that progressively reduce behavioral control and cognitive flexibility while increasing limbic negative emotion. Recent discoveries indicate neuroimmune signaling underlies addiction and co-morbid depression. Low threshold microglia undergo progressive stages of innate immune activation involving astrocytes and neurons with repeated drug abuse, stress, and/or cell damage signals. Increased brain NF-κB transcription of proinflammatory chemokines, cytokines, oxidases, proteases, TLR and other genes create loops amplifying NF-κB transcription and innate immune target gene expression. Human post-mortem alcoholic brain has increased NF-κB and NF-κB target gene message, increased microglial markers and chemokine-MCP1. Polymorphisms of human NF-κB1 and other innate immune genes contribute to genetic risk for alcoholism. Animal transgenic and genetic studies link NF-κB innate immune gene expression to alcohol drinking. Human drug addicts show deficits in behavioral flexibility modeled pre-clinically using reversal learning. Binge alcohol, chronic cocaine, and lesions link addiction neurobiology to frontal cortex, neuroimmune signaling and loss of behavioral flexibility. Addiction also involves increasing limbic negative emotion and depression-like behavior that is reflected in hippocampal neurogenesis. Innate immune activation parallels loss of neurogenesis and increased depression-like behavior. Protection against loss of neurogenesis and negative affect by anti-oxidant, anti-inflammatory, anti-depressant, opiate antagonist and abstinence from ethanol dependence link limbic affect to changes in innate immune signaling. The hypothesis that innate immune gene induction underlies addiction and affective disorders creates new targets for therapy.

Nuclear factor kappa B (NF-kappa B) is an ubiquitous rapid response transcription factor in cells involved in immune and inflammatory reactions, and exerts its effect by expressing cytokines, chemokines, cell adhesion molecules, growth factors, and immunoreceptors. In this manner, NF-kappa B contributes to immunologically mediated diseases such as allograft rejection, rheumatoid arthritis, and bronchial asthma. The prototypic inducible form of NF-kappa B is a heterodimer composed of NF-kB1 and RelA, which both belong to the NF-kappa B/Rel family of proteins. Inactive NF-kappa B is present in the cytoplasm complexed with an inhibitory protein, I kappa B. NF-kappa B is activated by a number of incoming signals from the cell surface. Released from I kappa B inhibition, NF-kappa B translocates into the nucleus and binds to the kappa B motif of the target gene. The NF-kappa B activation process can be inhibited by pharmacologic agents at each activation step. Glucocorticoids inhibit NF-kappa B by directly associating with NF-kappa B or by upregulating I kappa B expression. Cyclosporine and tacrolimus prevent NF-kappa B activation by inhibiting the action of calcineurin, a phosphatase that indirectly induces I kappa B degradation. Deoxyspergualin inhibits NF-kappa B by blocking its nuclear translocation. Aspirin and salicylates inhibit upstream events inducing I kappa B phosphorylation. Tepoxalin and antioxidants inhibit NF-kappa B activation by influencing the redox state of the cell. Further research is required to develop more specific inhibitors to treat diseases mediated by NF-kappa B.

Ligation of TLR4 with LPS in macrophages leads to the production of proinflammatory cytokines, which are central to eliminate viral and bacterial infection. However, uncontrolled TLR4 activation may contribute to pathogenesis of inflammatory diseases such as septic shock. In this study, we found microRNA-210 was induced in murine macrophages by LPS. Transfection of miR-210 mimics significantly inhibited LPS-induced production of inflammatory cytokines. In contrast, transfection of anti-miR-210 inhibitors increased LPS-induced expression of proinflammatory cytokines. Furthermore, we demonstrated that miR-210 targets NF-κB1. Therefore, our data identify miR-210 as a very important feedback negative regulator for LPS-induced production of proinflammatory cytokines.

Nuclear Factor-kB (NF-kB), is a transcription factor composed of dimeric complexes of p50 (NF-kB1) or p52 (NF-kB2) usually associated with members of the Rel family (p65, c-Rel, Rel B) which have potent transactivation domains. Different combinations of NF-kB/Rel proteins bind distinct kB sites to regulate the transcription of different genes. In resting cells NF-kB resides in the cytoplasm in inactive form, complexed to members of a family of inhibitory proteins referred to as IkB. The bound IkB masks the NF-kB nuclear localization signal and thereby inhibits its nuclear transport. NF-kB can be activated by a variety of signals relevant to pathophysiology including inflammatory cytokines and bacterial lipopolysaccharides (LPS) as well as oxidative and fluid mechanical stress. Upon activation by these stimuli, IkB is phosphorylated and subsequently degraded. Phosphorylation targets IkB for ubiquitination and degradation by the 26S proteasome thus leading to NF-kB nuclear translocation. The same proteolytic pathway is involved in the processing of the p105 and p100 precursors to generate mature p50 and p52 subunits, respectively. Once in the nucleus, NF-kB is able to regulate the expression of many genes involved in the immune and inflammatory responses (i.e. inflammatory cytokines and adhesion molecules). Thus, new approaches to modulating NF-kB activation, and as a consequence inflammatory or metastatic processes, may take advantage of the selectivity of the ubiquitination and ATP-dependent proteolytic processes leading to IkB turnover. This review will analyze the current strategies aimed at interfering with NF-kB activation and will consider the ubiquitination system as a new selective target for the development of new anti-inflammatory therapies.

Lupus nephritis (LN) is a serious manifestation of systemic lupus erythematosus. Therapeutic studies in mouse LN models do not always predict outcomes of human therapeutic trials, raising concerns about the human relevance of these preclinical models. In this study, we used an unbiased transcriptional network approach to define, in molecular terms, similarities and differences among three lupus models and human LN. Genome-wide gene-expression networks were generated using natural language processing and automated promoter analysis and compared across species via suboptimal graph matching. The three murine models and human LN share both common and unique features. The 20 commonly shared network nodes reflect the key pathologic processes of immune cell infiltration/activation, endothelial cell activation/injury, and tissue remodeling/fibrosis, with macrophage/dendritic cell activation as a dominant cross-species shared transcriptional pathway. The unique nodes reflect differences in numbers and types of infiltrating cells and degree of remodeling among the three mouse strains. To define mononuclear phagocyte-derived pathways in human LN, gene sets activated in isolated NZB/W renal mononuclear cells were compared with human LN kidney profiles. A tissue compartment-specific macrophage-activation pattern was seen, with NF-κB1 and PPARγ as major regulatory nodes in the tubulointerstitial and glomerular networks, respectively. Our study defines which pathologic processes in murine models of LN recapitulate the key transcriptional processes active in human LN and suggests that there are functional differences between mononuclear phagocytes infiltrating different renal microenvironments.

MicroRNAs (miRNAs) are short non-coding RNAs that post-transcriptionally regulate gene expression. Hsa-miR-9 has been shown to have opposite functions in different tumour types; however, the underlying mechanism is unclear. Here we show that hsa-miR-9 is down-regulated in metastatic melanomas compared to primary melanomas. Overexpression of miR-9 in melanoma cells resulted in significantly decreased cell proliferation and migratory capacity with decreased F-actin polymerization and down-regulation of multiple GTPases involved in cytoskeleton remodelling. miR-9 overexpression induced significant down-regulation of Snail1 with a concomitant increase in E-cadherin expression. In contrast, knockdown of miR-9 increased Snail1 expression as well as melanoma cell proliferation and migration capacity. Mechanistically, miR-9 expression down-regulated NF-κB1 in melanoma and the effect was abolished by mutations in the putative miR-9 binding sites within the 3'-untranslated region (UTR) of NF-κB1. Anti-miR-9 miRNA inhibitor also increased the expression of NF-κB1. The effects of miR-9 on Snail1 expression and melanoma cell proliferation and migration were rescued by overexpression of NF-κB1 in these cells. Furthermore, miR-9 overexpression resulted in significantly decreased melanoma growth and metastasis in vivo. In summary, miR-9 inhibits melanoma proliferation and metastasis through down-regulation of the NF-κB1-Snail1 pathway. This study finds a new mechanism that miR-9 utilizes to decrease E-cadherin expression and inhibit melanoma progression. The results suggest that function of microRNAs is context and tumour type-specific.

Recent studies have identified a class of small non-coding RNA molecules, named microRNA (miRNA), that is dysregulated in malignant brain glioblastoma. Substantial data have indicated that miRNA-16 (miR-16) plays a significant role in tumors of various origins. This miRNA has been linked to various aspects of carcinogenesis, including cell apoptosis and migration. However, the molecular functions of miR-16 in gliomagenesis are largely unknown. We have shown that the expression of miR-16 in human brain glioma tissues was lower than in non-cancerous brain tissues, and that the expression of miR-16 decreased with increasing degrees of malignancy. Our data suggest that the expression of miR-16 and nuclear factor (NF)-κB1 was negatively correlated with glioma levels. MicroRNA-16 decreased glioma malignancy by downregulating NF-κB1 and MMP9, and led to suppressed invasiveness of human glioma cell lines SHG44, U87, and U373. Our results also indicated that upregulation of miR-16 promoted apoptosis by suppressing BCL2 expression. Finally, the upregulation of miR-16 in a nude mice model of human glioma resulted in significant suppression of glioma growth and invasiveness. Taken together, our experiments have validated the important role of miR-16 as a tumor suppressor gene in glioma growth and invasiveness, and revealed a novel mechanism of miR-16-mediated regulation in glioma growth and invasiveness through inhibition of BCL2 and the NF-κB1/MMP-9 signaling pathway. Therefore, our experiments suggest the possible future use of miR-16 as a therapeutic target in gliomas.

Common variable immunodeficiency (CVID), characterized by recurrent infections, is the most prevalent symptomatic antibody deficiency. In ∼90% of CVID-affected individuals, no genetic cause of the disease has been identified. In a Dutch-Australian CVID-affected family, we identified a NFKB1 heterozygous splice-donor-site mutation (c.730+4A>G), causing in-frame skipping of exon 8. NFKB1 encodes the transcription-factor precursor p105, which is processed to p50 (canonical NF-κB pathway). The altered protein bearing an internal deletion (p.Asp191_Lys244delinsGlu; p105ΔEx8) is degraded, but is not processed to p50ΔEx8. Altered NF-κB1 proteins were also undetectable in a German CVID-affected family with a heterozygous in-frame exon 9 skipping mutation (c.835+2T>G) and in a CVID-affected family from New Zealand with a heterozygous frameshift mutation (c.465dupA) in exon 7. Given that residual p105 and p50—translated from the non-mutated alleles—were normal, and altered p50 proteins were absent, we conclude that the CVID phenotype in these families is caused by NF-κB1 p50 haploinsufficiency.

The IκB kinase (IKK) complex plays a well-documented role in innate and adaptive immunity. This function has been widely attributed to its role as the central activator of the NF-κB family of transcription factors. However, another important consequence of IKK activation is the regulation of TPL-2, a MEK kinase that is required for activation of ERK-1/2 MAP kinases in myeloid cells following Toll-like receptor and TNF receptor stimulation. In unstimulated cells, TPL-2 is stoichiometrically complexed with the NF-κB inhibitory protein NF-κB1 p105, which blocks TPL-2 access to its substrate MEK, and the ubiquitin-binding protein ABIN-2 (A20-binding inhibitor of NF-κB 2), both of which are required to maintain TPL-2 protein stability. Following agonist stimulation, the IKK complex phosphorylates p105, triggering its K48-linked ubiquitination and degradation by the proteasome. This releases TPL-2 from p105-mediated inhibition, facilitating activation of MEK, in addition to modulating NF-κB activation by liberating associated Rel subunits for translocation into the nucleus. IKK-induced proteolysis of p105, therefore, can directly regulate both NF-κB and ERK MAP kinase activation via NF-κB1 p105. TPL-2 is critical for production of the proinflammatory cytokine TNF during inflammatory responses. Consequently, there has been considerable interest in the pharmaceutical industry to develop selective TPL-2 inhibitors as drugs for the treatment of TNF-dependent inflammatory diseases, such as rheumatoid arthritis and inflammatory bowel disease. This review summarizes our current understanding of the regulation of TPL-2 signaling function, and also the complex positive and negative roles of TPL-2 in immune and inflammatory responses.

Nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) activation play central roles in the induction of gene expression in innate immune cells following pathogen recognition. TPL-2 (tumor progression locus 2) is the MAP 3-kinase component of an ERK-1/2 (extracellular signal-regulated kinase 1/2) MAPK pathway activated by Toll-like receptor and tumor necrosis factor receptor family stimulation. In this review, we discuss results obtained from our laboratory and others that show that TPL-2 signaling function is directly controlled by the inhibitor of NF-κB (IκB) kinase (IKK) complex. Significantly, this means that IKK controls both NF-κB and ERK activation. TPL-2 is stoichiometrically complexed with the NF-κB inhibitory protein, NF-κB1 p105, and the ubiquitin-binding protein ABIN-2, both of which are required to maintain TPL-2 protein stability. Binding to p105 also prevents TPL-2 from phosphorylating MEK (MAPK/ERK kinase), its downstream target. Agonist stimulation releases TPL-2 from p105-inhibition by IKK-mediated phosphorylation of p105, which triggers degradation of p105 by the proteasome. This facilitates TPL-2 phosphorylation of MEK, in addition to liberating p105-associated Rel subunits to translocate into the nucleus. We also examine evidence that TPL-2 is critical for the induction of inflammation and may play a role in development and/or progression of certain types of cancer. Finally, we consider the potential of TPL-2 as an anti-inflammatory drug target for treatment of certain types of inflammatory disease and cancer.

Interferons (IFNs) are proteins involved in many functions including antiviral and antimicrobial response, apoptosis, cell cycle control and mediating other cytokines. IFN gamma (IFNG) is a proinflammatory cytokine that modulates many immune-related genes. In this study we examine genetic variation in IFNG, IFNGR1, IFNGR2 and interferon regulatory factors (IRFs) to determine associations with colon and rectal cancer and survival after diagnosis. We include data from two population-based incident studies of colon cancer (1555 cases and 1956 controls) and rectal cancer (754 cases and 959 controls). Five tagSNPs in IFNG, IRF2 and IRF3 were associated with colon cancer and eight tagSNPs in IFNGR1, IFNGR2, IRF2, IRF4, IRF6 and IRF8 were associated with rectal cancer. IRF3 rs2304204 was associated with the strongest direct association and IRF2 3775554 with the strongest inverse association for colon cancer [odds ratios (ORs) 1.43, 95% confidence interval (CI) 1.12-1.82 for recessive model and 0.52, 95% CI 0.28-0.97 for unrestricted model]. For rectal cancer, IFNGR1 rs3799488 was directly associated with risk (OR 2.30, 95% CI 1.04-5.09 for recessive model), whereas IRF6 rs861020 was inversely associated with risk (OR 0.57, 95% CI 0.34-0.95). Several single-nucleotide polymorphisms interacted significant with both NF-κB1 and IL6 and with aspirin/non-steroidal anti-inflammatory drugs and cigarette smoking. Using a summary score to estimate mutational load, we observed a hazard rate ratio (HRR) close to 5.00 (95% CI 2.73-8.99) for both colon and rectal (HRR 4.83, 95% CI 2.34-10.05) cancer for those in the category having the most at-risk genotypes. These data suggest the importance of IFN-signaling pathway on colon and rectal cancer risk and survival after diagnosis.

The canonical inhibitor of nuclear factor κB kinase subunit β (IKK-β)–nuclear factor of κ light polypeptide gene enhancer in B cells 1 (NF-κB1) pathway has been well documented to promote insulin resistance; however, the noncanonical NF-κB–inducing kinase (NIK)–NF-κB2 pathway is not well understood in obesity. Additionally, the contribution of counter-regulatory hormones, particularly glucagon, to hyperglycemia in obesity is unclear. Here we show that NIK promotes glucagon responses in obesity. Hepatic NIK was abnormally activated in mice with dietary or genetic obesity. Systemic deletion of Map3k14, encoding NIK, resulted in reduced glucagon responses and hepatic glucose production (HGP). Obesity is associated with high glucagon responses, and liver-specific inhibition of NIK led to lower glucagon responses and HGP and protected against hyperglycemia and glucose intolerance in obese mice. Conversely, hepatocyte-specific overexpression of NIK resulted in higher glucagon responses and HGP. In isolated mouse livers and primary hepatocytes, NIK also promoted glucagon action and glucose production, at least in part by increasing cAMP response element-binding (CREB) stability. Therefore, overactivation of liver NIK in obesity promotes hyperglycemia and glucose intolerance by increasing the hyperglycemic response to glucagon and other factors that activate CREB.

The development of pancreatic cancer requires the acquisition of oncogenic KRas mutations and upregulation of growth factor signaling, but the relationship between these is not well established. Here, we show that mutant KRas alters mitochondrial metabolism in pancreatic acinar cells, resulting in increased generation of mitochondrial reactive oxygen species (mROS). Mitochondrial ROS then drives the dedifferentiation of acinar cells to a duct-like progenitor phenotype and progression to PanIN. This is mediated via the ROS-receptive kinase protein kinase D1 and the transcription factors NF-κB1 and NF-κB2, which upregulate expression of the epidermal growth factor, its ligands, and their sheddase ADAM17. In vivo, interception of KRas-mediated generation of mROS reduced the formation of pre-neoplastic lesions. Hence, our data provide insight into how oncogenic KRas interacts with growth factor signaling to induce the formation of pancreatic cancer.

Anoikis is apoptosis initiated upon cell detachment from the native extracellular matrix. Since survival upon detachment from basement membrane is required for metastasis, the ability to resist anoikis contributes to the metastatic potential of breast tumors. miR-200c, a potent repressor of epithelial to mesenchymal transition, is expressed in luminal breast cancers, but is lost in more aggressive basal-like, or triple negative breast cancers (TNBC). We previously demonstrated that miR-200c restores anoikis sensitivity to TNBC cells by directly targeting the neurotrophic receptor tyrosine kinase, TrkB. In this study, we identify a TrkB ligand, neurotrophin 3 (NTF3), as capable of activating TrkB to induce anoikis resistance, and show that NTF3 is also a direct target of miR-200c. We present the first evidence that anoikis resistant TNBC cells up-regulate both TrkB and NTF3 when suspended, and show that this up-regulation is necessary for survival in suspension. We further demonstrate that NF-κB activity increases 6 fold in suspended TNBC cells, and identify RelA and NF-κB1 as the transcription factors responsible for suspension-induced up-regulation of TrkB and NTF3. Consequently, inhibition of NF-κB activity represses anoikis resistance. Taken together, our findings define a critical mechanism for transcriptional and post-transcriptional control of suspension-induced up-regulation of TrkB and NTF3 in anoikis resistant breast cancer cells.

NF-κB plays central roles in regulation of diverse biological processes, including innate and adaptive immunity and inflammation. HSV-1 is the archetypal member of the alphaherpesviruses, with a large genome encoding over 80 viral proteins, many of which are involved in virus-host interactions and show immune modulatory capabilities. In this study, we demonstrated that the HSV-1 ICP0 protein, a viral E3 ubiquitin ligase, was shown to significantly suppress tumor necrosis factor alpha (TNF-α)-mediated NF-κB activation. ICP0 was demonstrated to bind to the NF-κB subunits p65 and p50 by coimmunoprecipitation analysis. ICP0 bound to the Rel homology domain (RHD) of p65. Fluorescence microscopy demonstrated that ICP0 abolished nuclear translocation of p65 upon TNF-α stimulation. Also, ICP0 degraded p50 via its E3 ubiquitin ligase activity. The RING finger (RF) domain mutant ICP0 (ICP0-RF) lost its ability to inhibit TNF-α-mediated NF-κB activation and p65 nuclear translocation and degrade p50. Notably, the RF domain of ICP0 was sufficient to interact with p50 and abolish NF-κB reporter gene activity. Here, it is for the first time shown that HSV-1 ICP0 interacts with p65 and p50, degrades p50 through the ubiquitin-proteasome pathway, and prevents NF-κB-dependent gene expression, which may contribute to immune evasion and pathogenesis of HSV-1.

The transcription factor NF-κB regulates the expression of a broad number of genes central to immune and inflammatory responses. We identified a new molecular network that comprises specifically the NF-κB family member NF-κB1 (p50) and miR-146a, and we show that in mast cells it contributes to the regulation of cell homeostasis and survival, while in T lymphocytes it modulates T cell memory formation. Increased mast cell survival was due to unbalanced expression of pro- and antiapoptotic factors and particularly to the complete inability of p50-deleted mast cells to induce expression of miR-146a, which in the context of mast cell survival acted as a proapoptotic factor. Interestingly, in a different cellular context, namely, human and mouse primary T lymphocytes, miR-146a and NF-κB p50 did not influence cell survival or cytokine production but rather T cell expansion and activation in response to T cell receptor (TCR) engagement. Our data identify a new molecular network important in modulating adaptive and innate immune responses and show how the same activation-induced microRNA (miRNA) can be similarly regulated in different cell types even in response to different stimuli but can still determine very different outcomes, likely depending on the specific transcriptome.

Rel/NF-κB transcription factors regulate inflammatory and immune responses. Despite possible subunit redundancy, NF-κB1-deficient (Nfkb1(-/-)) mice were profoundly protected from sterile CD4 T cell-dependent acute inflammatory arthritis and peritonitis. We evaluated CD4 T cell function in Nfkb1(-/-) mice and found increased apoptosis and selectively reduced GM-CSF production. Apoptosis was blocked by expression of a Bcl-2 transgene without restoring a disease response. In contrast with wild-type cells, transfer of Nfkb1(-/-) or GM-CSF-deficient CD4 T cells into RAG-1-deficient (Rag1(-/-)) mice failed to support arthritis induction. Injection of GM-CSF into Nfkb1(-/-) mice fully restored the disease response, suggesting that T cells are an important source of GM-CSF during acute inflammation. In Ag-induced peritonitis, NF-κB1-dependent GM-CSF production in CD4 T cells was required for disease and for generation of inflammatory monocyte-derived dendritic cells (MoDC), but not conventional dendritic cells. MoDC were identified in inflamed synovium and draining lymph nodes during arthritis. These MoDC produced high levels of MCP-1, a potent chemoattractant for monocytes. This study revealed two important findings: NF-κB1 serves a critical role in the production of GM-CSF by activated CD4 T cells during inflammatory responses, and GM-CSF derived from these cells drives the generation of MoDC during inflammatory disease.

BACKGROUND

Oral cancer, which is the fourth most common cancer in Taiwanese men, is associated with environmental carcinogens. The possibility that genetic predisposition in nuclear factor-kappa B (NF-κB)-signaling pathways activation is linked to the development of oral squamous cell carcinoma (OSCC) requires investigation. The current study examines associations between polymorphisms within promoter regions of NFKB1 encoding NF-κB1 and NFKBIA encoding IkappaBalpha (IκBα) with both the susceptibility to develop OSCC and the clinicopathological characteristics of the tumors.

RESULTS

Genetic polymorphisms of NFKB1 and NFKBIA were analyzed by a real-time polymerase chain reaction (real-time PCR) for 462 patients with oral cancer and 520 non-cancer controls. We found that NFKB1 -94 ATGG1/ATGG2, -94 ATGG2/ATGG2, and the combination of -94 ATGG1/ATGG2 and ATGG2/ATGG2 genotypes NFKBIA -826 T (CT+TT) and -881 G (AG+GG) allelic carriages, were more prevalent in OSCC patients than in non-cancer participants. Moreover, we found that NFKB1 or NFKBIA gene polymorphisms seem to be related to susceptibility to develop oral cancer linked to betel nut and tobacco consumption. Finally, patients with oral cancer who had at least one -519 T allele of the NFKBIA gene were at higher risk for developing distant metastasis (P<.05), compared with those patients CC homozygotes.

CONCLUSIONS

Our results suggest that NFKB1 -94 ATTG2, NFKBIA -826 T, and -881 G alleles are associated with oral carcinogenesis. The combination of NFKB1 or NFKBIA gene polymorphisms and environmental carcinogens appears related to an increased risk of oral cancer. More importantly, the genetic polymorphism of NFKBIA -519 might be a predictive factor for the distal metastasis of OSCC in Taiwanese.

As key molecules that drive progression and chemoresistance in gastrointestinal cancers, epidermal growth factor receptor (EGFR) and HER2 have become efficacious drug targets in this setting. Lapatinib is an EGFR/HER2 kinase inhibitor suppressing signaling through the RAS/RAF/MEK (MAP/ERK kinase)/MAPK (mitogen-activated protein kinase) and PI3K (phosphoinositide 3-kinase)/AKT pathways. Histone deacetylase inhibitors (HDACi) are a novel class of agents that induce cell cycle arrest and apoptosis following the acetylation of histone and nonhistone proteins modulating gene expression and disrupting HSP90 function inducing the degradation of EGFR-pathway client proteins. This study sought to evaluate the therapeutic potential of combining lapatinib with the HDACi panobinostat in colorectal cancer (CRC) cell lines with varying EGFR/HER2 expression and KRAS/BRAF/PIK3CA mutations. Lapatinib and panobinostat exerted concentration-dependent antiproliferative effects in vitro (panobinostat range 7.2-30 nmol/L; lapatinib range 7.6-25.8 μmol/L). Combined lapatinib and panobinostat treatment interacted synergistically to inhibit the proliferation and colony formation in all CRC cell lines tested. Combination treatment resulted in rapid induction of apoptosis that coincided with increased DNA double-strand breaks, caspase-8 activation, and PARP cleavage. This was paralleled by decreased signaling through both the PI3K and MAPK pathways and increased downregulation of transcriptional targets including NF-κB1, IRAK1, and CCND1. Panobinostat treatment induced downregulation of EGFR, HER2, and HER3 mRNA and protein through transcriptional and posttranslational mechanisms. In the LoVo KRAS mutant CRC xenograft model, the combination showed greater antitumor activity than either agent alone, with no apparent increase in toxicity. Our results offer preclinical rationale warranting further clinical investigation combining HDACi with EGFR and HER2-targeted therapies for CRC treatment.

BACKGROUND

The rising epidemic of obesity is associated with cognitive decline and is considered as one of the major risk factors for neurodegenerative diseases. Neuroinflammation is a critical component in the progression of several neurological and neurodegenerative diseases. Increased metabolic flux to the brain during overnutrition and obesity can orchestrate stress response, blood-brain barrier (BBB) disruption, recruitment of inflammatory immune cells from peripheral blood and microglial cells activation leading to neuroinflammation. The lack of an effective treatment for obesity-associated brain dysfunction may have far-reaching public health ramifications, urgently necessitating the identification of appropriate preventive and therapeutic strategies. The objective of our study was to investigate the neuroprotective effects of Momordica charantia (bitter melon) on high-fat diet (HFD)-associated BBB disruption, stress and neuroinflammatory cytokines.

METHODS

C57BL/6 female mice were fed HFD with and without bitter melon (BM) for 16 weeks. BBB disruption was analyzed using Evans blue dye. Phosphate-buffered saline (PBS) perfused brains were analyzed for neuroinflammatory markers such as interleukin-22 (IL-22), IL-17R, IL-16, NF-κB1, and glial cells activation markers such as Iba1, CD11b, GFAP and S100β. Additionally, antioxidant enzymes, ER-stress proteins, and stress-resistant transcription factors, sirtuin 1 (Sirt1) and forkhead box class O transcription factor (FoxO) were analyzed using microarray, quantitative real-time RT-PCR, western immunoblotting and enzymatic assays. Systemic inflammation was analyzed using cytokine antibody array.

RESULTS

BM ameliorated HFD-associated changes in BBB permeability as evident by reduced leakage of Evans blue dye. HFD-induced glial cells activation and expression of neuroinflammatory markers such as NF-κB1, IL-16, IL-22 as well as IL-17R were normalized in the brains of mice supplemented with BM. Similarly, HFD-induced brain oxidative stress was significantly reduced by BM supplementation with a concomitant reduction in FoxO, normalization of Sirt1 protein expression and up-regulation of Sirt3 mRNA expression. Furthermore, plasma antioxidant enzymes and pro-inflammatory cytokines were also normalized in mice fed HFD with BM as compared to HFD-fed mice.

CONCLUSIONS

Functional foods such as BM offer a unique therapeutic strategy to improve obesity-associated peripheral inflammation and neuroinflammation.

The cytokine B cell activating factor (BAFF) and its receptor, BAFF receptor (BAFF-R), modulate signaling cascades critical for B cell development and survival. We identified a novel mutation in TNFRSF13C, the gene encoding human BAFF-R, that is present in both tumor and germline tissue from a subset of patients with non-Hodgkin lymphoma. This mutation encodes a His159Tyr substitution in the cytoplasmic tail of BAFF-R adjacent to the TRAF3 binding motif. Signaling through this mutant BAFF-R results in increased NF-κB1 and NF-κB2 activity and increased immunoglobulin production compared with the wild-type (WT) BAFF-R. This correlates with increased TRAF2, TRAF3, and TRAF6 recruitment to His159Tyr BAFF-R. In addition, we document a requirement for TRAF6 in WT BAFF-R signaling. Together, these data identify a novel lymphoma-associated mutation in human BAFF-R that results in NF-κB activation and reveals TRAF6 as a necessary component of normal BAFF-R signaling.

Mature dendritic cells (DCs) are crucial for the induction of adaptive immune responses and perturbed DC homeostasis can result in autoimmune disease. Either uncontrolled expansion or enhanced survival of DCs can result in a variety of autoimmune diseases in mouse models. In addition, increased maturation signals, through overexpression of surface Toll-like receptors (TLRs) or stimulation by type I interferon (IFN), has been associated with systemic autoimmunity. Whereas recent studies have focused on identifying factors required for initiating the maturation process, the possibility that resting DCs also express molecules that 'hold' them in an immature state has generally not been considered. Here we show that nuclear factor-κB1 (NF-κB1) is crucial for maintaining the resting state of DCs. Self-antigen-pulsed unstimulated DCs that do not express NF-κB1 were able to activate CD8(+) T lymphocytes and induce autoimmunity. We further show that NF-κB1 negatively regulates the spontaneous production of tumor necrosis factor-α (TNF-α), which is associated with increased granzyme B expression in cytotoxic T lymphocytes (CTLs). These findings provide a new perspective on functional DC maturation and a potential mechanism that may account for pathologic T cell activation.

The aggressive course of uveal melanoma is believed to reflect its unusually invasive and metastatic nature, which is associated with the nuclear factor kappaB (NF-κB) pathway. MicroRNAs (miRNAs) have been implicated in the regulation of various biological and pathological processes in cancer, however, the special role of miR-9 in uveal melanoma metastasis is largely unknown. In the present study, we showed that miR-9 is significantly reduced in highly invasive uveal melanoma cell lines, and suppressed migration and invasion of highly invasive cells. Furthermore, miR-9 negatively modulated NF-κB1 expression by direct targeting at its 3'-UTRs. Additionally, downstream targets of NF-κB1, such as MMP-2, MMP-9 and VEGFA, were regulated by miR-9 in the same pattern as NF-κB1. Therefore, miR-9 suppresses uveal melanoma cell migration and invasion partly through downregulation of the NF-κB1 signaling pathway.