IRAK1

Gene Summary

Gene:IRAK1; interleukin 1 receptor associated kinase 1
Aliases: IRAK, pelle
Location:Xq28
Summary:This gene encodes the interleukin-1 receptor-associated kinase 1, one of two putative serine/threonine kinases that become associated with the interleukin-1 receptor (IL1R) upon stimulation. This gene is partially responsible for IL1-induced upregulation of the transcription factor NF-kappa B. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:interleukin-1 receptor-associated kinase 1
Source:NCBIAccessed: 13 March, 2017

Ontology:

What does this gene/protein do?
Show (50)
Pathways:What pathways are this gene/protein implicaed in?
Show (3)

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 13 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Cell Proliferation
  • Gene Regulatory Networks
  • Hepatocellular Carcinoma
  • Single Nucleotide Polymorphism
  • MicroRNAs
  • X Chromosome
  • Bladder Cancer
  • Genetic Predisposition
  • Biomarkers, Tumor
  • siRNA
  • Phosphorylation
  • Gene Expression Profiling
  • Risk Factors
  • Polymerase Chain Reaction
  • Transfection
  • Gene Knockdown Techniques
  • Messenger RNA
  • Young Adult
  • NF-kappa B
  • Case-Control Studies
  • RNA Interference
  • Oligonucleotide Array Sequence Analysis
  • Down-Regulation
  • MYD88
  • Mutation
  • Toll-Like Receptors
  • Reproducibility of Results
  • Pancreatic Cancer
  • Waldenstrom's Macroglobulinemia
  • Cancer Gene Expression Regulation
  • Neoplastic Cell Transformation
  • Interleukin-1 Receptor-Associated Kinases
  • Genotype
  • Apoptosis
  • RTPCR
  • Systems Biology
  • Signal Transduction
  • Prostate Cancer
  • Toll-Like Receptor 4
  • beta Catenin
  • TNF Receptor-Associated Factor 6
  • Western Blotting
Tag cloud generated 13 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: IRAK1 (cancer-related)

Rothschild DE, Zhang Y, Diao N, et al.
Enhanced Mucosal Defense and Reduced Tumor Burden in Mice with the Compromised Negative Regulator IRAK-M.
EBioMedicine. 2017; 15:36-47 [PubMed] Free Access to Full Article Related Publications
Aberrant inflammation is a hallmark of inflammatory bowel disease (IBD) and colorectal cancer. IRAK-M is a critical negative regulator of TLR signaling and overzealous inflammation. Here we utilize data from human studies and Irak-m(-/-) mice to elucidate the role of IRAK-M in the modulation of gastrointestinal immune system homeostasis. In human patients, IRAK-M expression is up-regulated during IBD and colorectal cancer. Further functional studies in mice revealed that Irak-m(-/-) animals are protected against colitis and colitis associated tumorigenesis. Mechanistically, our data revealed that the gastrointestinal immune system of Irak-m(-/-) mice is highly efficient at eliminating microbial translocation following epithelial barrier damage. This attenuation of pathogenesis is associated with expanded areas of gastrointestinal associated lymphoid tissue (GALT), increased neutrophil migration, and enhanced T-cell recruitment. Further evaluation of Irak-m(-/-) mice revealed a splice variant that robustly activates NF-κB signaling. Together, these data identify IRAK-M as a potential target for future therapeutic intervention.

Pellé L, Cipollini M, Tremmel R, et al.
Association between CYP2E1 polymorphisms and risk of differentiated thyroid carcinoma.
Arch Toxicol. 2016; 90(12):3099-3109 [PubMed] Related Publications
Differentiated thyroid carcinoma (DTC) results from complex interactions between genetic and environmental factors. Known etiological factors include exposure to ionizing radiations, previous thyroid diseases, and hormone factors. It has been speculated that dietary acrylamide (AA) formed in diverse foods following the Maillard's reaction could be a contributing factor for DTC in humans. Upon absorption, AA is biotransformed mainly by cytochrome P450 2E1 (CYP2E1) to glycidamide (GA). Considering that polymorphisms within CYP2E1 were found associated with endogenous levels of AA-Valine and GA-Valine hemoglobin adducts in humans, we raised the hypothesis that specific CYP2E1 genotypes could be associated with the risk of DTC. Analysis of four haplotype tagging SNPs (ht-SNPs) within the locus in a discovery case-control study (N = 350/350) indicated an association between rs2480258 and DTC risk. This ht-SNP resides within a linkage disequilibrium block spanning intron VIII and the 3'-untranslated region. Extended analysis in a large replication set (2429 controls and 767 cases) confirmed the association, with odds ratios for GA and AA genotypes of 1.24 (95 % confidence interval (CI) 1.03-1.48) and 1.56 (95 % CI, 1.06-2.30), respectively. Functionally, the minor allele was associated with low levels of CYP2E1 mRNA and protein expression as well as lower enzymatic activity in a series of 149 human liver samples. Our data support the hypothesis that inter-individual differences in CYP2E1 activity could modulate the risk of developing DTC suggesting that the exposure to specific xenobiotics, such as AA, could play a role in this process.

Adams AK, Bolanos LC, Dexheimer PJ, et al.
IRAK1 is a novel DEK transcriptional target and is essential for head and neck cancer cell survival.
Oncotarget. 2015; 6(41):43395-407 [PubMed] Free Access to Full Article Related Publications
The chromatin-binding DEK protein was recently reported to promote the growth of HPV+ and HPV- head and neck squamous cell carcinomas (HNSCCs). Relevant cellular and molecular mechanism(s) controlled by DEK in HNSCC remain poorly understood. While DEK is known to regulate specific transcriptional targets, global DEK-dependent gene networks in HNSCC are unknown. To identify DEK transcriptional signatures we performed RNA-Sequencing (RNA-Seq) in HNSCC cell lines that were either proficient or deficient for DEK. Bioinformatic analyses and subsequent validation revealed that IRAK1, a regulator of inflammatory signaling, and IRAK1-dependent regulatory networks were significantly repressed upon DEK knockdown in HNSCC. According to TCGA data, 14% of HNSCC specimens overexpressed IRAK1, thus supporting possible oncogenic functions. Furthermore, genetic or pharmacologic inhibition of IRAK1 in HNSCC cell lines was sufficient to attenuate downstream signaling such as ERK1/2 and to induce HNSCC cell death by apoptosis. Finally, targeting DEK and IRAK1 simultaneously enhanced cell death as compared to targeting either alone. Our findings reveal that IRAK1 promotes cell survival and is an attractive therapeutic target in HNSCC cells. Thus, we propose a model wherein IRAK1 stimulates tumor signaling and phenotypes both independently and in conjunction with DEK.

Wu C, Chen Y, Wang F, et al.
Pelle Modulates dFoxO-Mediated Cell Death in Drosophila.
PLoS Genet. 2015; 11(10):e1005589 [PubMed] Free Access to Full Article Related Publications
Interleukin-1 receptor-associated kinases (IRAKs) are crucial mediators of the IL-1R/TLR signaling pathways that regulate the immune and inflammation response in mammals. Recent studies also suggest a critical role of IRAKs in tumor development, though the underlying mechanism remains elusive. Pelle is the sole Drosophila IRAK homolog implicated in the conserved Toll pathway that regulates Dorsal/Ventral patterning, innate immune response, muscle development and axon guidance. Here we report a novel function of pll in modulating apoptotic cell death, which is independent of the Toll pathway. We found that loss of pll results in reduced size in wing tissue, which is caused by a reduction in cell number but not cell size. Depletion of pll up-regulates the transcription of pro-apoptotic genes, and triggers caspase activation and cell death. The transcription factor dFoxO is required for loss-of-pll induced cell death. Furthermore, loss of pll activates dFoxO, promotes its translocation from cytoplasm to nucleus, and up-regulates the transcription of its target gene Thor/4E-BP. Finally, Pll physically interacts with dFoxO and phosphorylates dFoxO directly. This study not only identifies a previously unknown physiological function of pll in cell death, but also shed light on the mechanism of IRAKs in cell survival/death during tumorigenesis.

Fonte E, Agathangelidis A, Reverberi D, et al.
Toll-like receptor stimulation in splenic marginal zone lymphoma can modulate cell signaling, activation and proliferation.
Haematologica. 2015; 100(11):1460-8 [PubMed] Free Access to Full Article Related Publications
Recent studies on splenic marginal zone lymphoma identified distinct mutations in genes belonging to the B-cell receptor and Toll-like receptor signaling pathways, thus pointing to their potential implication in the biology of the disease. However, limited data is available regarding the exact role of TLRs. We aimed at characterizing the expression pattern of TLRs in splenic marginal zone lymphoma cells and their functional impact on the activation, proliferation and viability of malignant cells in vitro. Cells expressed significant levels of TLR1, TLR6, TLR7, TLR8, TLR9 and TLR10 mRNA; TLR2 and TLR4 showed a low, variable pattern of expression among patients whereas TLR3 and TLR5 mRNAs were undetectable; mRNA specific for TLR signaling molecules and adapters was also expressed. At the protein level, TLR1, TLR6, TLR7, TLR9 and TLR10 were detected. Stimulation of TLR1/2, TLR2/6 and TLR9 with their respective ligands triggered the activation of IRAK kinases, MAPK and NF-κB signaling pathways, and the induction of CD86 and CD25 activation molecules, although in a heterogeneous manner among different patient samples. TLR-induced activation and cell viability were also inhibited by a specific IRAK1/4 inhibitor, thus strongly supporting the specific role of TLR signaling in these processes. Furthermore, TLR2/6 and TLR9 stimulation also significantly increased cell proliferation. In conclusion, we demonstrate that splenic marginal zone lymphoma cells are equipped with functional TLR and signaling molecules and that the stimulation of TLR1/2, TLR2/6 and TLR9 may play a role in regulating disease pathobiology, likely promoting the expansion of the neoplastic clone.

Guo ZL, Yu B, Ning BT, et al.
Genetically modified "obligate" anaerobic Salmonella typhimurium as a therapeutic strategy for neuroblastoma.
J Hematol Oncol. 2015; 8:99 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Neuroblastoma currently has poor prognosis, therefore we proposed a new strategy by targeting neuroblastoma with genetically engineered anaerobic Salmonella (Sal-YB1).
METHODS: Nude and nonobese diabetic-severe combined immunodeficiency (NOD-SCID) orthotopic mouse models were used, and Sal-YB1 was administered via tail vein. The therapeutic effectiveness, bio-safety, and mechanisms were studied.
RESULTS: No mice died of therapy-related complications. Tumor size reduction was 70 and 30% in nude and NOD-SCID mice, respectively. No Salmonella was detected in the urine; 75% mice had positive stool culture if diaminopimelic acid was added, but all turned negative subsequently. Tumor tissues had more Sal-YB1 infiltration, necrosis, and shrinkage in Sal-YB1-treated mice. Significantly higher expression of TLR4, TNF-stimulated gene 6 protein (TSG6), and cleaved caspase 1, 3, 8, and 9 was found in the tumor masses of the Sal-YB1-treated group with a decrease of interleukin 1 receptor-associated kinase (IRAK) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha (IκBα). There was a high release of TNFα both in human macrophages and mouse tumor tissues with Sal-YB1 treatment. The antitumor effect of the supernatant derived from macrophages treated with Sal-YB1 could be reversed with TNFα and pan-caspase inhibitors.
CONCLUSIONS: This new approach in targeting neuroblastoma by bio-engineered Salmonella with the assistance of macrophages indirectly may have a clinical therapeutic impact in the future.

Wang L, Li G, Yao ZQ, et al.
MicroRNA regulation of viral immunity, latency, and carcinogenesis of selected tumor viruses and HIV.
Rev Med Virol. 2015; 25(5):320-41 [PubMed] Related Publications
MicroRNAs (miRNAs) function as key regulators in immune responses and cancer development. In the contexts of infection with oncogenic viruses, miRNAs are engaged in viral persistence, latency establishment and maintenance, and oncogenesis. In this review, we summarize the potential roles and mechanisms of viral and cellular miRNAs in the host-pathogen interactions during infection with selected tumor viruses and HIV, which include (i) repressing viral replication and facilitating latency establishment by targeting viral transcripts, (ii) evading innate and adaptive immune responses via toll-like receptors, RIG-I-like receptors, T-cell receptor, and B-cell receptor pathways by targeting signaling molecules such as TRAF6, IRAK1, IKKε, and MyD88, as well as downstream targets including regulatory cytokines such as tumor necrosis factor α, interferon γ, interleukin 10, and transforming growth factor β, (iii) antagonizing intrinsic and extrinsic apoptosis pathways by targeting pro-apoptotic or anti-apoptotic gene transcripts such as the Bcl-2 family and caspase-3, (iv) modulating cell proliferation and survival through regulation of the Wnt, PI3K/Akt, Erk/MAPK, and Jak/STAT signaling pathways, as well as the signaling pathways triggered by viral oncoproteins such as Epstein-Barr Virus LMP1, by targeting Wnt-inhibiting factor 1, SHIP, pTEN, and SOCSs, and (v) regulating cell cycle progression by targeting cell cycle inhibitors such as p21/WAF1 and p27/KIP1. Further elucidation of the interaction between miRNAs and these key biological events will facilitate our understanding of the pathogenesis of viral latency and oncogenesis and may lead to the identification of miRNAs as novel targets for developing new therapeutic or preventive interventions.

Dussiau C, Trinquand A, Lhermitte L, et al.
Targeting IRAK1 in T-cell acute lymphoblastic leukemia.
Oncotarget. 2015; 6(22):18956-65 [PubMed] Free Access to Full Article Related Publications
T-cell acute lymphoblastic leukemia (T-ALL) represents expansion of cells arrested at specific stages of thymic development with the underlying genetic abnormality often determining the stage of maturation arrest. Although their outcome has been improved with current therapy, survival rates remain only around 50% at 5 years and patients may therefore benefit from specific targeted therapy. Interleukin receptor associated kinase 1 (IRAK1) is a ubiquitously expressed serine/threonine kinase that mediates signaling downstream to Toll-like (TLR) and Interleukin-1 Receptors (IL1R). Our data demonstrated that IRAK1 is overexpressed in all subtypes of T-ALL, compared to normal human thymic subpopulations, and is functional in T-ALL cell lines. Genetic knock-down of IRAK1 led to apoptosis, cell cycle disruption, diminished proliferation and reversal of corticosteroid resistance in T-ALL cell lines. However, pharmacological inhibition of IRAK1 using a small molecule inhibitor (IRAK1/4-Inh) only partially reproduced the results of the genetic knock-down. Altogether, our data suggest that IRAK1 is a candidate therapeutic target in T-ALL and highlight the requirement of next generation IRAK1 inhibitors.

Lee J, Tian Y, Chan ST, et al.
TNF-α Induced by Hepatitis C Virus via TLR7 and TLR8 in Hepatocytes Supports Interferon Signaling via an Autocrine Mechanism.
PLoS Pathog. 2015; 11(5):e1004937 [PubMed] Free Access to Full Article Related Publications
Invasion by infectious pathogens can elicit a range of cytokine responses from host cells. These cytokines provide the initial host defense mechanism. In this report, we demonstrate that TNF-α, a pro-inflammatory cytokine, can be induced by hepatitis C virus (HCV) in its host cells in a biphasic manner. The initial induction of TNF-α by HCV was prompt and could be blocked by the antibody directed against the HCV E2 envelope protein and by chemicals that inhibit endocytosis, indicating the specificity of endocytic uptake of HCV in this induction. Further studies indicated that the induction of TNF-α was dependent on toll-like receptors 7 and 8 (TLR7/8) but not on other intracellular pattern recognition receptors. Consistently, siRNA-mediated gene silencing of the downstream effectors in the TLR7/8 signaling pathway including MyD88, IRAK1, TRAF6, TAK1 and p65 NF-κB suppressed the expression of TNF-α. The role of p65 NF-κB in the induction of TNF-α via transcriptional up-regulation was further confirmed by the chromatin immunoprecipitation assay. TNF-α induced by HCV could activate its own receptor TNFR1 on hepatocytes to suppress HCV replication. This suppressive effect of TNF-α on HCV was due to its role in supporting interferon signaling, as the suppression of its expression led to the loss of IFNAR2 and impaired interferon signaling and the induction of interferon-stimulated genes. In conclusion, our results indicate that hepatocytes can sense HCV infection via TLR7/8 to induce the expression of TNF-α, which inhibits HCV replication via an autocrine mechanism to support interferon signaling.

Liu R, Liu C, Chen D, et al.
FOXP3 Controls an miR-146/NF-κB Negative Feedback Loop That Inhibits Apoptosis in Breast Cancer Cells.
Cancer Res. 2015; 75(8):1703-13 [PubMed] Free Access to Full Article Related Publications
FOXP3 functions not only as the master regulator in regulatory T cells, but also as an X-linked tumor suppressor. The tumor-suppressive activity of FOXP3 has been observed in tumor initiation, but its role during tumor progression remains controversial. Moreover, the mechanism of FOXP3-mediated tumor-suppressive activity remains largely unknown. Using chromatin immunoprecipitation (ChIP) sequencing, we identified a series of potential FOXP3-targeted miRNAs in MCF7 cells. Notably, FOXP3 significantly induced the expression of miR-146a/b. In vitro, FOXP3-induced miR-146a/b prevented tumor cell proliferation and enhanced apoptosis. Functional analyses in vitro and in vivo revealed that FOXP3-induced miR-146a/b negatively regulates NF-κB activation by inhibiting the expression of IRAK1 and TRAF6. In ChIP assays, FOXP3 directly bound the promoter region of miR-146a but not of miR-146b, and FOXP3 interacted directly with NF-κB p65 to regulate an miR-146-NF-κB negative feedback regulation loop in normal breast epithelial and tumor cells, as demonstrated with luciferase reporter assays. Although FOXP3 significantly inhibited breast tumor growth and migration in vitro and metastasis in vivo, FOXP3-induced miR-146a/b contributed only to the inhibition of breast tumor growth. These data suggest that miR-146a/b contributes to FOXP3-mediated tumor suppression during tumor growth by triggering apoptosis. The identification of a FOXP3-miR-146-NF-κB axis provides an underlying mechanism for disruption of miR-146 family member expression and constitutive NF-κB activation in breast cancer cells. Linking the tumor suppressor function of FOXP3 to NF-κB activation reveals a potential therapeutic approach for cancers with FOXP3 defects.

Liu R, Yi B, Wei S, et al.
FOXP3-miR-146-NF-κB Axis and Therapy for Precancerous Lesions in Prostate.
Cancer Res. 2015; 75(8):1714-24 [PubMed] Free Access to Full Article Related Publications
The tumor-suppressive activity of FOXP3 has been observed in tumor initiation, but the underlying mechanism still remains largely unknown. Here, we identified a FOXP3-microRNA-146 (miR-146)-NF-κB axis in vitro and in vivo in prostate cancer cells. We observed that FOXP3 dramatically induced the expression of miR-146a/b, which contributed to transcriptional inhibition of IRAK1 and TRAF6, in prostate cancer cell lines. Tissue-specific deletion of Foxp3 in mouse prostate caused a significant reduction of miR-146a and upregulation of NF-κB activation. In addition, prostatic intraepithelial neoplasia lesions were observed in miR-146a-mutant mice as well as in Foxp3-mutant mice. Notably, the NF-κB inhibitor bortezomib inhibited cell proliferation and induced apoptosis in prostate epithelial cells, attenuating prostatic intraepithelial neoplasia formation in Foxp3-mutant mice. Our data suggest that the FOXP3-miR-146-NF-κB axis has a functional role during tumor initiation in prostate cancer. Targeting the miR-146-NF-κB axis may provide a new therapeutic approach for prostate cancers with FOXP3 defects.

Lee KH, Jang AH, Yoo CG
17-Allylamino-17-Demethoxygeldanamycin and the Enhancement of PS-341-Induced Lung Cancer Cell Death by Blocking the NF-κB and PI3K/Akt Pathways.
Am J Respir Cell Mol Biol. 2015; 53(3):412-21 [PubMed] Related Publications
PS-341 is a highly selective and potent proteasome inhibitor that is cytotoxic to various types of cancer. However, no objective response was seen in a clinical trial with PS-341 as a single agent in non-small cell lung cancer. Its antitumor activity is limited by the simultaneously activated antiapoptosis pathway. Recently, PS-341-induced NF-κB activation via IκBα degradation has been suggested to be one of its antiapoptotic effects. In this study, we investigated the effects of a combined application of the heat shock protein (Hsp) 90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) with PS-341 in lung cancer cells. Hsp90 inhibition with 17-AAG was effective in enhancing PS-341-induced lung cancer cell death in vitro and in vivo. 17-AAG pretreatment induced the degradation of upstream regulators of IκB, IL-1R-associated kinase-1 (IRAK-1), and IκB kinases (IKKs), dose and time dependently, which resulted in blocking of PS-341-induced IκBα degradation, p65 nuclear translocation, transcriptional activity, and NF-κB-regulated antiapoptotic gene expressions such as COX-2. The concentrations of 17-AAG used for combinatorial treatment with PS-341 did not change cell viability or the activity of proteasome complex. Moreover, 17-AAG pretreatment decreased the level of phsophorylated Akt at serine 473 residue and suppressed active Akt-dependent inactivation of glycogen synthase kinase 3β. 17-AAG mediated the dissociation of its client proteins (IRAK-1, IKKs, and Akt) from the Hsp90 complex. As a result, it induced degradation of target proteins. Our results suggest that the combination of 17-AAG and PS-341 could be an effective anticancer therapy that overcomes the limited effects of PS-341.

Cui J, Chen Y, Wang HY, Wang RF
Mechanisms and pathways of innate immune activation and regulation in health and cancer.
Hum Vaccin Immunother. 2014; 10(11):3270-85 [PubMed] Free Access to Full Article Related Publications
Research on innate immune signaling and regulation has recently focused on pathogen recognition receptors (PRRs) and their signaling pathways. Members of PRRs sense diverse microbial invasions or danger signals, and initiate innate immune signaling pathways, leading to proinflammatory cytokines production, which, in turn, instructs adaptive immune response development. Despite the diverse functions employed by innate immune signaling to respond to a variety of different pathogens, the innate immune response must be tightly regulated. Otherwise, aberrant, uncontrolled immune responses will lead to harmful, or even fatal, consequences. Therefore, it is essential to better discern innate immune signaling and many regulators, controlling various signaling pathways, have been identified. In this review, we focus on the recent advances in our understanding of the activation and regulation of innate immune signaling in the host response to pathogens and cancer.

Zhang X, Dang Y, Li P, et al.
Expression of IRAK1 in lung cancer tissues and its clinicopathological significance: a microarray study.
Int J Clin Exp Pathol. 2014; 7(11):8096-104 [PubMed] Free Access to Full Article Related Publications
The interleukin-1 receptor associated kinases 1 (IRAK1) is a down stream effector molecule of the toll like receptor (TLR) signaling pathway, which is involved in inflammation, autoimmunity and cancer. However, the role of IRAK1 in lung cancer remains unclarified. Herein, we investigated the protein expression and the clinicopathological significance of IRAK1 in 3 formalin-fixed paraffin-embedded lung cancer tissue microarrays by using immunohistochemistry, which included 365 tumor and 30 normal lung tissues. We found that the expression of IRAK1 in lung cancer was significantly higher compared with that in normal lung tissues (P=0.002). Receiver operating characteristic (ROC) curves were generated to evaluate the power of IRAK1 to distinguish lung cancer from non-cancerous lung tissue. The area under curve (AUC) of ROC of IRAK1 was 0.643 (95% CI 0.550~0.735, P=0.009). Additionally, IRAK1 expression was related to clinical TNM stage (r=0.241, P < 0.001), lymph node metastasis (r=0.279, P < 0.001) and tumor size (r=0.299, P < 0.001) in lung cancer. In the subgroup of non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC), the positive rates of IRAK1 were both higher than that in the normal lung tissues (P=0.003, P=0.002, respectively). Further spearman analysis showed that IRAK1 protein in NSCLC was positive correlated with clinical TNM stage (r=0.222, P < 0.001), lymph node metastasis (r=0.277, P < 0.001), tumor size (r=0.292, P < 0.001) and distal metastasis (r=0.110, P=0.043). In conclusion, the expression of IRAK1 protein might be valuable in identifying patients with increased risks of lung cancer and might act as a target for diagnosis and gene therapy for lung cancer.

Jurado-Camino T, Córdoba R, Esteban-Burgos L, et al.
Chronic lymphocytic leukemia: a paradigm of innate immune cross-tolerance.
J Immunol. 2015; 194(2):719-27 [PubMed] Related Publications
Infections are a significant cause of morbidity and mortality in patients with chronic lymphocytic leukemia (CLL). The pathogenesis of infections is multifactorial and includes hypogammaglobulinemia, conventional therapy with alkylating drugs, and recently, purine analogs and mAb-associated T cells. Patients without these risk factors also suffer from infections, although the mechanism remains unknown. In a cohort of 70 patients with CLL, we demonstrated that their monocytes were locked into a refractory state and were unable to mount a classic inflammatory response to pathogens. In addition, they exhibited the primary features of endotoxin tolerance, including low cytokine production, high phagocytic activity, and impaired Ag presentation. The involvement of miR-146a in this phenomenon was suspected. We found miR-146a target genes, such as IRAK1 and TRAF6, were manifestly downregulated. Our study provides a new explanation for infections in patients with CLL and describes a cross-tolerance between endotoxins and tumors.

Scholten DJ, Timmer CM, Peacock JD, et al.
Down regulation of Wnt signaling mitigates hypoxia-induced chemoresistance in human osteosarcoma cells.
PLoS One. 2014; 9(10):e111431 [PubMed] Free Access to Full Article Related Publications
Osteosarcoma (OS) is the most common type of solid bone cancer and remains the second leading cause of cancer-related death for children and young adults. Hypoxia is an element intrinsic to most solid-tumor microenvironments, including that of OS, and is associated with resistance to therapy, poor survival, and a malignant phenotype. Cells respond to hypoxia through alterations in gene expression, mediated most notably through the hypoxia-inducible factor (HIF) class of transcription factors. Here we investigate hypoxia-induced changes in the Wnt/β-catenin signaling pathway, a key signaling cascade involved in OS pathogenesis. We show that hypoxia results in increased expression and signaling activation of HIF proteins in human osteosarcoma cells. Wnt/β-catenin signaling is down-regulated by hypoxia in human OS cells, as demonstrated by decreased active β-catenin protein levels and axin2 mRNA expression (p<0.05). This down-regulation appears to rely on both HIF-independent and HIF-dependent mechanisms, with HIF-1α standing out as an important regulator. Finally, we show that hypoxia results in resistance of human OS cells to doxorubicin-mediated toxicity (6-13 fold increase, p<0.01). These hypoxic OS cells can be sensitized to doxorubicin treatment by further inhibition of the Wnt/β-catenin signaling pathway (p<0.05). These data support the conclusion that Wnt/β-catenin signaling is down-regulated in human OS cells under hypoxia and that this signaling alteration may represent a viable target to combat chemoresistant OS subpopulations in a hypoxic niche.

Su B, Luo T, Zhu J, et al.
Interleukin-1β/Iinterleukin-1 receptor-associated kinase 1 inflammatory signaling contributes to persistent Gankyrin activation during hepatocarcinogenesis.
Hepatology. 2015; 61(2):585-97 [PubMed] Related Publications
UNLABELLED: Hepatocellular carcinoma (HCC) is a prototype of inflammation-associated cancer. Oncoprotein Gankyrin, which mostly increases in HCC, plays a critical role in HCC development and metastasis. However, the exact mechanism of Gankyrin up-regulation in HCC remains unclear. A Gankyrin luciferase reporter was developed to screen a potential regulator for Gankyrin from a list of proinflammatory cytokines, and interleukin (IL)-1β was found as one of its activators. In clinical premalignant and malignant liver disease samples, enhanced IL-1β/interleukin-1 receptor-associated kinase 1 (IRAK-1) signaling accompanied by increased Gankyrin was observed. Lower expression of Gankyrin and phospho-IRAK-1 are favorable prognostic markers for HCC. A similar correlation was observed in the diethylnitrosamine (DEN) model of rat hepatocarcinogenesis. The results from Gankyrin reporter activity, real-time polymerase chain reaction, or immunoblotting further confirmed the up-regulation of Gankyrin by IL-1β/IRAK-1 inflammatory signaling. Moreover, a series of Gankyrin's truncated reporters were constructed, and electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) were performed to analyze the properties of Gankyrin promoter. Mechanistically, the core promoter of Gankyrin contains the binding site of nuclear factor Y (NF-Y) family members, which can recruit histone acetyltransferase coactivator E1A-binding protein p300 (p300) or CREB-binding protein (CBP) to promote Gankyrin transcription. Conversely, knockdown of NF-Y, p300, or CBP inhibits Gankyrin expression. IL-1β stimulation causes sequential phosphorylation of IRAK-1, c-Jun N-terminal kinase (JNK), and p300 and enhances recruitment of the p300/CBP/NF-Y complex to Gankyrin promoter. Inhibition of phospho-JNK impairs IL-1β/IRAK-1 signaling-mediated up-regulation of Gankyrin.
CONCLUSION: The finding of IL-1β/IRAK-1 signaling promoting Gankyrin expression through JNK and NF-Y/p300/CBP complex provides a fresh view on inflammation-enhanced hepatocarcinogenesis.

Rhyasen GW, Starczynowski DT
IRAK signalling in cancer.
Br J Cancer. 2015; 112(2):232-7 [PubMed] Free Access to Full Article Related Publications
Innate immune signalling has an essential role in inflammation, and the dysregulation of signalling components of this pathway is increasingly being recognised as an important mediator in cancer initiation and progression. In some malignancies, dysregulation of inflammatory toll-like receptor (TLR) and interleukin-1 receptor (IL1R) signalling is typified by increased NF-κB activity, and it occurs through somatic mutations, chromosomal deletions, and/or transcriptional deregulation. Interleukin-1 receptor-associated kinase (IRAK) family members are mediators of TLR/IL1R superfamily signalling, and mounting evidence implicates these kinases as viable cancer targets. Although there have been previous efforts aimed at the development of IRAK kinase inhibitors, this is currently an area of renewed interest for cancer drug development.

Lee MJ, Min BJ, Choung HK, et al.
Genome-wide DNA methylation profiles according to Chlamydophila psittaci infection and the response to doxycycline treatment in ocular adnexal lymphoma.
Mol Vis. 2014; 20:1037-47 [PubMed] Free Access to Full Article Related Publications
PURPOSE: To compare genome-wide DNA methylation profiles according to Chlamydophila psittaci (Cp) infection status and the response to doxycycline treatment in Korean patients with ocular adnexal extranodal marginal zone B-cell lymphoma (EMZL).
METHODS: Twelve ocular adnexal EMZL cases were classified into two groups (six Cp-positive cases and six Cp-negative cases). Among the 12 cases, eight were treated with doxycycline as first-line therapy, and they were divided into two groups according to their response to the treatment (four doxy-responders and four doxy-nonresponders). The differences in the DNA methylation states of 27,578 methylation sites in 14,000 genes were evaluated using Illumina bead assay technology. We also validated the top-ranking differentially methylated genes (DMGs) with bisulfite direct sequencing or pyrosequencing.
RESULTS: The Infinium methylation chip assay revealed 180 DMGs in the Cp-positive group (74 hypermethylated genes and 106 hypomethylated genes) compared to the Cp-negative group. Among the 180 DMGs, DUSP22, which had two significantly hypomethylated loci, was validated, and the correlation was significant for one CpG site (Spearman coefficient=0.6478, p=0.0262). Regarding the response to doxycycline treatment, a total of 778 DMGs were revealed (389 hypermethylated genes and 336 hypomethylated genes in the doxy-responder group). In a subsequent replication study for representative hypomethylated (IRAK1) and hypermethylated (CXCL6) genes, the correlation between the bead chip analysis and pyrosequencing was significant (Spearman coefficient=0.8961 and 0.7619, respectively, p<0.05).
CONCLUSIONS: Ocular adnexal EMZL showed distinct methylation patterns according to Cp infection and the response to doxycycline treatment in this genome-wide methylation study. Among the candidate genes, DUSP22 has a methylation status that was likely attributable to Cp infection. Our data also suggest that the methylation statuses of IRAK1 and CXCL6 may reflect the response to doxycycline treatment.

Kalinski T, Sel S, Hütten H, et al.
Curcumin blocks interleukin-1 signaling in chondrosarcoma cells.
PLoS One. 2014; 9(6):e99296 [PubMed] Free Access to Full Article Related Publications
Interleukin (IL)-1 signaling plays an important role in inflammatory processes, but also in malignant processes. The essential downstream event in IL-1 signaling is the activation of nuclear factor (NF)-κB, which leads to the expression of several genes that are involved in cell proliferation, invasion, angiogenesis and metastasis, among them VEGF-A. As microenvironment-derived IL-1β is required for invasion and angiogenesis in malignant tumors, also in chondrosarcomas, we investigated IL-1β-induced signal transduction and VEGF-A expression in C3842 and SW1353 chondrosarcoma cells. We additionally performed in vitro angiogenesis assays and NF-κB-related gene expression analyses. Curcumin is a substance which inhibits IL-1 signaling very early by preventing the recruitment of IL-1 receptor associated kinase (IRAK) to the IL-1 receptor. We demonstrate that IL-1 signaling and VEGF-A expression are blocked by Curcumin in chondrosarcoma cells. We further show that Curcumin blocks IL-1β-induced angiogenesis and NF-κB-related gene expression. We suppose that IL-1 blockade is an additional treatment option in chondrosarcoma, either by Curcumin, its derivatives or other IL-1 blocking agents.

Martínez-Trillos A, Pinyol M, Navarro A, et al.
Mutations in TLR/MYD88 pathway identify a subset of young chronic lymphocytic leukemia patients with favorable outcome.
Blood. 2014; 123(24):3790-6 [PubMed] Related Publications
Mutations in Toll-like receptor (TLR) and myeloid differentiation primary response 88 (MYD88) genes have been found in chronic lymphocytic leukemia (CLL) at low frequency. We analyzed the incidence, clinicobiological characteristics, and outcome of patients with TLR/MYD88 mutations in 587 CLL patients. Twenty-three patients (3.9%) had mutations, 19 in MYD88 (one with concurrent IRAK1 mutation), 2 TLR2 (one with concomitant TLR6 mutation), 1 IRAK1, and 1 TLR5. No mutations were found in IRAK2 and IRAK4. TLR/MYD88-mutated CLL overexpressed genes of the nuclear factor κB pathway. Patients with TLR/MYD88 mutations were significantly younger (83% age ≤50 years) than those with no mutations. TLR/MYD88 mutations were the most frequent in young patients. Patients with mutated TLR/MYD88 CLL had a higher frequency of mutated IGHV and low expression of CD38 and ZAP-70. Overall survival (OS) was better in TLR/MYD88-mutated than unmutated patients in the whole series (10-year OS, 100% vs 62%; P = .002), and in the subset of patients age ≤50 years (100% vs 70%; P = .02). In addition, relative OS of TLR/MYD88-mutated patients was similar to that in the age- and gender-matched population. In summary, TLR/MYD88 mutations identify a population of young CLL patients with favorable outcome.

Pelle DW, Ringler JW, Peacock JD, et al.
Targeting receptor-activator of nuclear kappaB ligand in aneurysmal bone cysts: verification of target and therapeutic response.
Transl Res. 2014; 164(2):139-48 [PubMed] Related Publications
Aneurysmal bone cyst (ABC) is a benign tumor of bone presenting as a cystic, expansile lesion in both the axial and appendicular skeleton. Axial lesions demand special consideration, because treatment-related morbidity can be devastating. In similar lesions, such as giant cell tumor of bone (GCTB), the receptor-activator of nuclear kappaB ligand (RANKL)-receptor-activator of nuclear kappaB (RANK) signaling axis is essential to tumor progression. Although ABC and GCTB are distinct entities, they both contain abundant multinucleated giant cells and are osteolytic characteristically. We hypothesize that ABCs express both RANKL and RANK similarly in a cell-type specific manner, and that targeted RANKL therapy will mitigate ABC tumor progression. Cellular expression of RANKL and RANK was determined in freshly harvested ABC samples using laser confocal microscopy. A consistent cell-type-specific pattern was observed: fibroblastlike stromal cells expressed RANKL strongly whereas monocyte/macrophage precursor and multinucleated giant cells expressed RANK. Relative RANKL expression was determined by quantitative real-time polymerase chain reaction in ABC and GCTB tissue samples; no difference in relative expression was observed (P > 0.05). In addition, we review the case of a 5-year-old boy with a large, aggressive sacral ABC. After 3 months of targeted RANKL inhibition with denosumab, magnetic resonance imaging demonstrated tumor shrinkage, bone reconstitution, and healing of a pathologic fracture. Ambulation, and bowel and bladder function were restored at 6 months. Denosumab treatment was well tolerated. Post hoc analysis demonstrated strong RANKL expression in the pretreatment tumor sample. These findings demonstrate that RANKL-RANK signal activation is essential to ABC tumor progression. RANKL-targeted therapy may be an effective alternative to surgery in select ABC presentations.

Schwertheim S, Worm K, Schmid KW, Sheu-Grabellus SY
Valproic acid downregulates NF-κB p50 activity and IRAK-1 in a progressive thyroid carcinoma cell line.
Horm Metab Res. 2014; 46(3):181-6 [PubMed] Related Publications
Histone deacetylase inhibitor (HDACI) valproic acid (VPA) is a promising drug, currently in clinical phase 2, for the therapy of advanced/poorly differentiated thyroid cancer. The nuclear factor-κB (NF-κB) pathway is constitutively activated in most tumors, including thyroid carcinomas; this often contributes to aggressive tumor growth and therapeutic resistance. We hypothesized that VPA could be useful to decrease NF-κB activity in human thyroid cancer cells. To clarify this, we treated the highly progressive thyroid cancer cell line BHT-101 with VPA (1.0-3.0 mM) for 48 h. Real-time polymerase chain reaction (PCR) and Western blot were used to measure expression of NF-κB-regulatory genes and proteins. NF-κB p50 activity was measured using an ELISA-based colorimetric transcription factor assay kit. We found that VPA significantly and dose-dependently impaired NF-κB activity reducing DNA binding activity of NF-κB p50 subunit by 30% at 1 mM, 40% at 1.5 mM, and 70% at 3 mM. Expression of interleukin-1 receptor-associated kinase-1 (IRAK-1) protein, an upstream mediator of NF-κB activation, was reduced by ̴30% at 1 and 1.5 mM. Furthermore, 3 mM VPA treatment significantly decreased expressions of IRAK-1, phospho-IκBα and NF-κB p50 subunit protein by ̴ 50%. This is the first study to demonstrate that VPA decreases NF-κB activity in a progressive thyroid cancer cell line. Intriguingly, 1mM of VPA, a clinically safe dose in the therapeutic range for epilepsy, was sufficient to reduce NF-κB activity. Thus, VPA may be a promising agent to overcome chemoresistance in cancer therapy and to improve therapeutic efficiency.

Brodtkorb M, Lingjærde OC, Huse K, et al.
Whole-genome integrative analysis reveals expression signatures predicting transformation in follicular lymphoma.
Blood. 2014; 123(7):1051-4 [PubMed] Related Publications
Transformation of follicular lymphoma (FL) to a more aggressive disease is associated with rapid progression and death. Existing molecular markers for transformation are few and their clinical impact is limited. Here, we report on a whole-genome study of DNA copy numbers and gene expression profiles in serial FL biopsies. We identified 698 genes with high correlation between gene expression and copy number, and the molecular network most enriched for these cis-associated genes. This network includes 14 cis-associated genes directly related to the nuclear factor κB (NF-κB) pathway. For each of these 14 genes, the correlated NF-κB target genes were identified and corresponding expression scores were defined. The scores for 6 of the cis-associated NFκB pathway genes (BTK, IGBP1, IRAK1, ROCK1, TMED7-TICAM2, and TRIM37) were significantly associated with transformation. The results suggest that genes regulating B-cell survival and activation are involved in transformation of FL.

Hung PS, Liu CJ, Chou CS, et al.
miR-146a enhances the oncogenicity of oral carcinoma by concomitant targeting of the IRAK1, TRAF6 and NUMB genes.
PLoS One. 2013; 8(11):e79926 [PubMed] Free Access to Full Article Related Publications
MicroRNAs are short non-coding RNAs that regulate gene expression and are crucial to tumorigenesis. Oral squamous cell carcinoma (OSCC) is a prevalent malignancy worldwide. Up-regulation of miR-146 has been identified in OSCC tissues. However, the roles of miR-146 in carcinogenesis are controversial as it is suppressive in many other malignancies. The present study investigated the pathogenic implications of miR-146a in oral carcinogenesis. Microdissected OSCC exhibits higher levels of miR-146a expression than matched adjacent mucosal cells. The plasma miR-146a levels of patients are significantly higher than those of control subjects; these levels decrease drastically after tumor resection. miR-146a levels in tumors and in patients' plasma can be used to classify OSCC and non-disease status (sensitivity: >0.72). Exogenous miR-146a expression is significantly increased in vitro oncogenic phenotypes as well as during xenograft tumorigenesis and OSCC metastasis. The plasma miR-146a levels of these mice parallel the xenograft tumor burdens of the mice. A miR-146a blocker abrogates the growth of xenograft tumors. miR-146a oncogenic activity is associated with down-regulation of IRAK1, TRAF6 and NUMB expression. Furthermore, miR-146a directly targets the 3'UTR of NUMB and a region within the NUMB coding sequence when suppressing NUMB expression. Exogenous NUMB expression attenuates OSCC oncogenicity. Double knockdown of IRAK1 and TRAF6, and of TRAF6 and NUMB, enhance the oncogenic phenotypes of OSCC cells. Oncogenic enhancement modulated by miR-146a expression is attenuated by exogenous IRAK1 or NUMB expression. This study shows that miR-146a expression contributes to oral carcinogenesis by targeting the IRAK1, TRAF6 and NUMB genes.

Jeon HS, Lee YH, Lee SY, et al.
A common polymorphism in pre-microRNA-146a is associated with lung cancer risk in a Korean population.
Gene. 2014; 534(1):66-71 [PubMed] Related Publications
INTRODUCTION: MicroRNAs (miRs) play important roles in the development and progression of human cancers. MiR-146a down-regulates epidermal growth factor receptor and the nuclear factor-κB regulatory kinase interleukin-1 receptor-associated kinase 1 genes that play important roles in lung carcinogenesis. This study was conducted to evaluate the association between rs2910164C>G, a functional polymorphism in the pre-miR-146a, and lung cancer risk.
MATERIAL AND METHODS: The rs2910164C>G genotypes were determined in 1094 patients with lung cancer and 1100 healthy controls who were frequency matched for age and gender.
RESULTS: The rs2910164 CG or GG genotype was associated with a significantly decreased risk for lung cancer compared to that of the CC genotype (adjusted odds ratio=0.80, 95% confidence interval=0.66-0.96, P=0.02). When subjects were stratified according to smoking exposure (never, light and heavy smokers), the effect of the rs2910164C>G genotype on lung cancer risk was significant only in never smokers (adjusted odds ratio=0.66, 95% confidence interval=0.45-0.96, P=0.03, under a dominant model for the C allele) and decreased as smoking exposure level increased (Ptrend<0.001). In line with this result, the level of miR-146a expression in the tumor tissues was significantly higher in the GG genotype than in the CC or CG genotype only in never-smokers (P=0.02).
CONCLUSIONS: These findings suggest that the rs2910164C>G in pre-miR-146a may contribute to genetic susceptibility to lung cancer, and that miR-146a might be involved in lung cancer development.

Kumar DM, Patil V, Ramachandran B, et al.
Temozolomide-modulated glioma proteome: role of interleukin-1 receptor-associated kinase-4 (IRAK4) in chemosensitivity.
Proteomics. 2013; 13(14):2113-24 [PubMed] Related Publications
The current treatment for glioblastoma includes temozolomide (TMZ) chemotherapy, yet the mechanism of action of TMZ is not thoroughly understood. Here, we investigated the TMZ-induced changes in the proteome of the glioma-derived cell line (U251) by 2D DIGE. We found 95 protein spots to be significantly altered in their expression after TMZ treatment. MS identified four upregulated spots: aspartyl tRNA synthetase glutathione synthetase, interleukin-1 receptor-associated kinase-4 (IRAK4), and breast carcinoma amplified sequence-1 and one downregulated spot: optineurin. TMZ-induced regulation of these five genes was validated by RT-qPCR and Western blot analysis. RNAi-mediated knockdown of IRAK4, an important mediator of Toll-like receptors signaling and chemoresistance, rendered the glioma cells resistant to TMZ. High levels of IRAK4 induced upon TMZ treatment resulted in IRAK1 downregulation and inhibition of NFkB pathway. Endogenous IRAK4 protein, but not transcript levels in glioma cell lines, correlated with TMZ sensitivity. Thus, we have identified several TMZ-modulated proteins and discovered an important novel role for IRAK4 in determining TMZ sensitivity of glioma cells through its ability to inhibit Toll-like receptor signaling and NFkB pathway.

Kumar G, Breen EJ, Ranganathan S
Identification of ovarian cancer associated genes using an integrated approach in a Boolean framework.
BMC Syst Biol. 2013; 7:12 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Cancer is a complex disease where molecular mechanism remains elusive. A systems approach is needed to integrate diverse biological information for the prognosis and therapy risk assessment using mechanistic approach to understand gene interactions in pathways and networks and functional attributes to unravel the biological behaviour of tumors.
RESULTS: We weighted the functional attributes based on various functional properties observed between cancerous and non-cancerous genes reported from literature. This weighing schema was then encoded in a Boolean logic framework to rank differentially expressed genes. We have identified 17 genes to be differentially expressed from a total of 11,173 genes, where ten genes are reported to be down-regulated via epigenetic inactivation and seven genes are up-regulated. Here, we report that the overexpressed genes IRAK1, CHEK1 and BUB1 may play an important role in ovarian cancer. We also show that these 17 genes can be used to form an ovarian cancer signature, to distinguish normal from ovarian cancer subjects and that the set of three genes, CHEK1, AR, and LYN, can be used to classify good and poor prognostic tumors.
CONCLUSION: We provided a workflow using a Boolean logic schema for the identification of differentially expressed genes by integrating diverse biological information. This integrated approach resulted in the identification of genes as potential biomarkers in ovarian cancer.

Eiró N, González L, González LO, et al.
Relationship between the inflammatory molecular profile of breast carcinomas and distant metastasis development.
PLoS One. 2012; 7(11):e49047 [PubMed] Free Access to Full Article Related Publications
Inflammatory conditions may promote tumor progression and aggressiveness. In previous reports, we found a group of breast cancer tumors characterized by metalloprotease-11 (MMP-11) expression by intratumoral mononuclear inflammatory cells (MICs), which was associated with distant metastasis development. Thus, in the present study we evaluated the relationship between MMP-11 expression by MICs, distant metastasis development, and a wide panel of inflammatory factors in breast carcinoma. In an initial approach, we analyzed 65 factors associated with tumor progression and inflammation, in a tumor population classified in good or bad prognosis, based on MMP-11 expression by intratumoral MICs. The most differentially expressed factors were then analyzed in a wider tumor population classified according to MMP-11 expression by MICs and also according to metastasis development. These analyses were carried out by Real-time PCR. The results showed that of the 65 starting factors analyzed, those related with MMP-11 expression by MICs were: IL-1, -5, -6, -8, -17, -18, MMP-1, TIMP-1, ADAM-8, -10, -15, -23, ADAMTS-1, -2, -15, Annexin A2, IFNβ, Claudin-3, CCL-3, MyD88, IRAK-4 and NFκB. Of them, factors more differentially expressed between both groups of tumors were IL-1, IL-5, IL-6, IL-17, IFNβ and NFκB. Thereafter, we confirmed in the wider tumor population, that there is a higher expression of those factors in tumors infiltrated by MMP-11 positive MICs. Altogether these results indicate that tumors developing worse prognosis and identified by MMP-11 expression by intratumoral MICs, shows an up-regulation of inflammatory-related genes.

Srivastava R, Geng D, Liu Y, et al.
Augmentation of therapeutic responses in melanoma by inhibition of IRAK-1,-4.
Cancer Res. 2012; 72(23):6209-16 [PubMed] Free Access to Full Article Related Publications
Toll-like receptors (TLR) are expressed by a variety of cancers, including melanoma, but their functional contributions in cancer cells are uncertain. To approach this question, we evaluated the effects of stimulating or inhibiting the TLR/IL-1 receptor-associated kinases IRAK-1 and IRAK-4 in melanoma cells where their functions are largely unexplored. TLRs and TLR-related proteins were variably expressed in melanoma cell lines, with 42% expressing activated phospho-IRAK-1 constitutively and 85% expressing high levels of phospho-IRAK-4 in the absence of TLR stimulation. Immunohistochemical evaluation of melanoma tumor biopsies (n = 242) revealed two distinct patient populations, one that expressed p-IRAK-4 levels similar to normal skin (55%) and one with significantly higher levels than normal skin (45%). Levels of p-IRAK-4 levels did not correlate with clinical stage, gender, or age, but attenuated IRAK-1,-4 signaling with pharmacologic inhibitors or siRNA-enhanced cell death in vitro in combination with vinblastine. Moreover, in a xenograft mouse model of melanoma, the combined pharmacologic treatment delayed tumor growth and prolonged survival compared with subjects receiving single agent therapy. We propose p-IRAK-4 as a novel inflammation and prosurvival marker in melanoma with the potential to serve as a therapeutic target to enhance chemotherapeutic responses.

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