Gene Summary

Gene:TLR9; toll like receptor 9
Aliases: CD289
Summary:The protein encoded by this gene is a member of the Toll-like receptor (TLR) family, which plays a fundamental role in pathogen recognition and activation of innate immunity. TLRs are highly conserved from Drosophila to humans and share structural and functional similarities. They recognize pathogen-associated molecular patterns (PAMPs) that are expressed on infectious agents, and mediate the production of cytokines necessary for the development of effective immunity. Studies in mice and human indicate that this receptor mediates cellular response to unmethylated CpG dinucleotides in bacterial DNA to mount an innate immune response. [provided by RefSeq, Aug 2017]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:toll-like receptor 9
Source:NCBIAccessed: 01 September, 2019


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 01 September 2019 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 01 September, 2019 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: TLR9 (cancer-related)

Meliț LE, Mărginean CO, Mărginean CD, Mărginean MO
The Relationship between Toll-like Receptors and
J Immunol Res. 2019; 2019:8197048 [PubMed] Free Access to Full Article Related Publications
Innate immunity represents the first barrier against bacterial invasion. Toll-like receptors (TLRs) belong to the large family of pattern recognition receptors (PRRs), and their activation leads to the induction of inflammatory cytokines, chemokines, antigen-presenting molecules, and costimulatory molecules. Recent studies have focused on identifying the association between TLRs and

Kell SA, Kachura MA, Renn A, et al.
Preclinical development of the TLR9 agonist DV281 as an inhaled aerosolized immunotherapeutic for lung cancer: Pharmacological profile in mice, non-human primates, and human primary cells.
Int Immunopharmacol. 2019; 66:296-308 [PubMed] Related Publications
CpG-motif-containing oligodeoxynucleotides (CpG-ODN) activate innate immunity through Toll-Like Receptor (TLR) 9 signaling and generate local immune responses when delivered directly to the lung. Herein we describe pharmacological studies in mice, cynomolgus monkeys, and in human primary cells which support the development of DV281, a C-class CpG-ODN, as an inhaled aerosolized immunotherapeutic for lung cancer to be combined with an inhibitor of the anti-programmed cell death protein 1 (PD‑1) immune checkpoint. In vitro, DV281 potently induced Interferon (IFN)‑α from monkey and human peripheral blood mononuclear cells (PBMCs), stimulated interleukin‑6 production and proliferation in human B cells, and induced TLR9-dependent cytokine responses from mouse splenocytes. Intranasal delivery of DV281 to mice led to substantial but transient cytokine and chemokine responses in the lung. Lung responses to repeated intranasal DV281 were partially to fully reversible 2 weeks after the final dose and were absent in TLR9-deficient mice. Single escalating doses of aerosolized DV281 in monkeys induced dose-dependent induction of IFN-regulated genes in bronchoalveolar lavage cells and blood. In a repeat-dose safety study in monkeys, inhaled DV281 was well-tolerated, and findings were mechanism of action-related and non-adverse. Co-culture of human PBMC with DV281 and anti-PD‑1 antibody did not augment cytokine or cellular proliferation responses compared to DV281 alone, indicating that the combination did not lead to dysregulated cytokine responses. These studies support clinical development of inhaled aerosolized DV281 as a combination therapy with anti-PD‑1 antibody for lung cancer immunotherapy.

Panossian A, Seo EJ, Efferth T
Novel molecular mechanisms for the adaptogenic effects of herbal extracts on isolated brain cells using systems biology.
Phytomedicine. 2018; 50:257-284 [PubMed] Related Publications
INTRODUCTION: Adaptogens are natural compounds or plant extracts that increase adaptability and survival of organisms under stress. Adaptogens stimulate cellular and organismal defense systems by activating intracellular and extracellular signaling pathways and expression of stress-activated proteins and neuropeptides. The effects adaptogens on mediators of adaptive stress response and longevity signaling pathways have been reported, but their stress-protective mechanisms are still not fully understood.
AIM OF THE STUDY: The aim of this study was to identify key molecular mechanisms of adaptogenic plants traditionally used to treat stress and aging-related disorders, i.e., Rhodiola rosea, Eleutherococcus senticosus, Withania somnifera, Rhaponticum carthamoides, and Bryonia alba.
MATERIALS AND METHODS: To investigate the underlying molecular mechanisms of adaptogens, we conducted RNA sequencing to profile gene expression alterations in T98G neuroglia cells upon treatment of adaptogens and analyzed the relevance of deregulated genes to adaptive stress-response signaling pathways using in silico pathway analysis software.
RESULTS AND DISCUSSION: At least 88 of the 3516 genes regulated by adaptogens were closely associated with adaptive stress response and adaptive stress-response signaling pathways (ASRSPs), including neuronal signaling related to corticotropin-releasing hormone, cAMP-mediated, protein kinase A, and CREB; pathways related to signaling involving CXCR4, melatonin, nitric oxide synthase, GP6, Gαs, MAPK, neuroinflammation, neuropathic pain, opioids, renin-angiotensin, AMPK, calcium, and synapses; and pathways associated with dendritic cell maturation and G-coupled protein receptor-mediated nutrient sensing in enteroendocrine cells. All samples tested showed significant effects on the expression of genes encoding neurohormones CRH, GNRH, UCN, G-protein-coupled and other transmembrane receptors TLR9, PRLR, CHRNE, GP1BA, PLXNA4, a ligand-dependent nuclear receptor RORA, transmembrane channels, transcription regulators FOS, FOXO6, SCX, STAT5A, ZFPM2, ZNF396, ZNF467, protein kinases MAPK10, MAPK13, MERTK, FLT1, PRKCH, ROS1, TTN), phosphatases PTPRD, PTPRR, peptidases, metabolic enzymes, a chaperone (HSPA6), and other proteins, all of which modulate numerous life processes, playing key roles in several canonical pathways involved in defense response and regulation of homeostasis in organisms. It is for the first time we report that the molecular mechanism of actions of melatonin and plant adaptogens are alike, all adaptogens tested activated the melatonin signaling pathway by acting through two G-protein-coupled membrane receptors MT1 and MT2 and upregulation of the ligand-specific nuclear receptor RORA, which plays a role in intellectual disability, neurological disorders, retinopathy, hypertension, dyslipidemia, and cancer, which are common in aging. Furthermore, melatonin activated adaptive signaling pathways and upregulated expression of UCN, GNRH1, TLR9, GP1BA, PLXNA4, CHRM4, GPR19, VIPR2, RORA, STAT5A, ZFPM2, ZNF396, FLT1, MAPK10, MERTK, PRKCH, and TTN, which were commonly regulated by all adaptogens tested. We conclude that melatonin is an adaptation hormone playing an important role in regulation of homeostasis. Adaptogens presumably worked as eustressors ("stress-vaccines") to activate the cellular adaptive system by inducing the expression of ASRSPs, which then reciprocally protected cells from damage caused by distress. Functional investigation by interactive pathways analysis demonstrated that adaptogens activated ASRSPs associated with stress-induced and aging-related disorders such as chronic inflammation, cardiovascular health, neurodegenerative cognitive impairment, metabolic disorders, and cancer.
CONCLUSION: This study has elucidated the genome-wide effects of several adaptogenic herbal extracts in brain cells culture. These data highlight the consistent activation of ASRSPs by adaptogens in T98G neuroglia cells. The extracts affected many genes playing key roles in modulation of adaptive homeostasis, indicating their ability to modify gene expression to prevent stress-induced and aging-related disorders. Overall, this study provides a comprehensive look at the molecular mechanisms by which adaptogens exerts stress-protective effects.

Chihab H, Zaidane I, Elhabazi A, et al.
Toll-like receptor 9 polymorphisms and Hepatitis B virus clearance in Moroccan chronic carriers.
Gene. 2019; 687:212-218 [PubMed] Related Publications
OBJECTIVES: Toll-like receptor 9 (TLR9) plays a crucial role in the innate immune response against viral infections. The failure of this system may result, in an attenuated immune response against HBV. Recent research has focused on the possibility of targeting the defects in TLR9 pathway as a novel approach for anti-HBV treatment. Our study aimed to assess the impact of both TLR9 rs5743836 and rs187084 polymorphisms on spontaneous HBV clearance in Moroccan chronic HBV carriers.
METHODS: In this study, 239 individuals chronically infected with HBV (CHB) and 133 subjects who spontaneously resolved the infection (SRB) were genotyped using a Taqman allelic discrimination assay.
RESULTS/CONCLUSION: Remarkably, we observed a dosage effect of both SNPs on viral loads; with a significant increase of circulating HBV DNA within AA, AG to GG rs5743836 genotypes, whereas the inverse phenomenon was noticed within rs187084 genotypes. There were no consistent association between TLR9 polymorphisms and spontaneous clearance of HBV, however, a significant association was observed between rs187084 AA genotype and HBV progression to advanced liver disease. Further studies on larger populations might be necessary to understand the modulating effect of TLR9 polymorphisms on HBV loads that remain a viral factor of paramount importance to predict HCC development.

Leppänen J, Helminen O, Huhta H, et al.
Toll-like receptors 2, 4 and 9 and hypoxia markers HIF-1alpha and CAIX in pancreatic intraepithelial neoplasia.
APMIS. 2018; 126(11):852-863 [PubMed] Related Publications
Pancreatic cancer arises from precursor lesions called pancreatic intraepithelial neoplasia (PanIN) characterized by inflammatory microenvironment. In pancreatic cancer, strong innate immunity and hypoxia responses are typical. Occurrence and relationship of these responses in human PanINs is unknown. We have studied the expression of toll-like receptors (TLR) TLR2, TLR4 and TLR9, and hypoxia markers HIF-1alpha and Carbonic anhydrase IX (CAIX) in normal and inflamed pancreatic ducts, in PanINs and in cancers. The samples of 69 surgically resected pancreatic ductal adenocarcinoma patients were stained using immunohistochemistry. We found TLR2, TLR9, HIF-1alpha and CAIX to be prominently expressed in pancreatic intraepithelial neoplasia. Expression of TLR2 showed a linear increase from PanIN1 to PanIN3, while the highest TLR4 expression was detected in inflamed ducts, and TLR9 expression in PanIN1 lesions. Within the PanIN1-group, nuclear HIF-1alpha correlated with membranous and cytoplasmic TLR2 expression (ρ = 0.982 and 0.815; p < 0.001 and p = 0.025, respectively), and in the PanIN2-group nuclear HIF-1alpha correlated with nuclear TLR9 expression 0.636, p = 0.026). Our findings show that the expression of TLRs 2, 4 and 9, and hypoxia markers HIF-1alpha and CAIX is abnormal in pancreatic intraepithelial neoplasia suggesting that both the innate immunity activation and hypoxia response are involved in early pancreatic carcinogenesis. However, these processes might be independent.

Mosaad YM, Metwally SS, Farag RE, et al.
Association between Toll-Like Receptor 3 (TLR3) rs3775290, TLR7 rs179008, TLR9 rs352140 and Chronic HCV.
Immunol Invest. 2019; 48(3):321-332 [PubMed] Related Publications
BACKGROUND: Inconsistent results were reported on the association of TLRs polymorphisms with the risk of HCV infection and HCV-related diseases.
OBJECTIVE: to assess the relation between TLR3 rs3775290, TLR7 rs17900 and TLR9 rs352140 SNPs and chronic HCV in the Egyptian cohort and to study their relation to interferon response.
METHODS: TLR3 rs3775290, TLR7 rs179008 and TLR9 rs352140 gene polymorphisms were typed by RFLP for 100 patients with chronic HCV and 25 with HCC in addition to 100 healthy controls.
RESULTS: A significant higher frequency has been found for the CT genotype of TLR3 rs3775290 in chronic HCV infection (p < 0.001) and CC genotype and the combined genotype CC-AT-GA ♀ in controls (p < 0.001). Non-significant associations have been found for studied SNPs and HCC and response to interferon and also the viral load or the degree of fibrosis, however, the higher HCV viral load and the higher grade of fibrosis were associated with treatment failure (p < 0.001).
CONCLUSION: The heterozygous CT genotype of TLR3 rs3775290 may be a susceptibility risk factor for chronic HCV infection and the homozygous CC and the combined CC-AT-GA ♀ genotypes may be protective. The HCV viral load and the grades of liver fibrosis could be considered a risk factor for interferon treatment failure. It seems that the studied SNPs have no role in HCC development or failure of treatment. However, the small sample size is a limiting factor of the present study when interpreting the negative associations and that the current used cohort does not permit such conclusion.
ABBREVIATIONS: cHCV=chronic Hepatitis C virus, HCC=hepatocellular carcinoma, TLR=Toll like Receptor, RFLP=Restriction Fragment Length Polymorphism, SNP=Single Nucleotide Polymorphism, IFN-α= interferon alpha.

Niu Z, Tang W, Liu T, et al.
Cell-free DNA derived from cancer cells facilitates tumor malignancy through Toll-like receptor 9 signaling-triggered interleukin-8 secretion in colorectal cancer.
Acta Biochim Biophys Sin (Shanghai). 2018; 50(10):1007-1017 [PubMed] Related Publications
Circulating cell-free DNA (cfDNA) has become a potential diagnostic and prognostic biomarker for colorectal cancer (CRC). In non-cancerous diseases, it has been confirmed that cfDNA can be recognized by Toll-like receptor 9 (TLR9), leading to a significant biological change. Nevertheless, the biological significance of cfDNA and its relationship with TLR9 in tumor malignancy is still unclear. Therefore, the purpose of this study is to explore the biological role of cfDNA in colorectal cancer (CRC). The expression of TLR9 was measured in different CRC cell lines and cancerous samples by RT-PCR or immunohistochemistry, which showed that high expression of TLR9 was significantly correlated with the tumor metastasis, advanced TNM stage and poor prognosis of patients. Then, cfDNA was obtained from fluorouracil (5FU)-induced apoptotic cancer cells in vitro and transfection techniques were used to transfect siRNA and cDNA plasmid for TLR9. Cancer cells were stimulated using isolated cfDNA fragments, and results showed that cfDNA could promote colorectal cancer cell proliferation via TLR9. Meanwhile, we demonstrated that the cfDNA binding to TLR9 could facilitate cell migration and invasion. Finally, we demonstrated that cfDNA initiated downstream TLR9-MyD88 signaling and induced robust release of chemokine interleukin 8 (IL-8), which helped to elucidate the mechanisms underlying these phenomena. Our data suggest that cancer cell-derived cfDNA contributes to cancer progression through activation of TLR9-MyD88 signaling and IL-8 secretion in CRC. These findings provide a novel perspective for understanding of tumor progression and provoke a potential therapeutic target for CRC treatment.

Halec G, Scott ME, Farhat S, et al.
Toll-like receptors: Important immune checkpoints in the regression of cervical intra-epithelial neoplasia 2.
Int J Cancer. 2018; 143(11):2884-2891 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Toll-like receptors (TLRs) are innate immune defenders thought to be critical for the clearance of human papillomavirus (HPV) infections hence preventing the development of HPV-associated high-grade cervical intra-epithelial neoplasia (CIN2 or 3), a potential cervical cancer precursor. However, the role of TLRs in the regression of established cervical lesions, such as CIN2, is hindered by a lack of prospective design studies. Using SYBR green real-time PCR assays, we have examined the gene expression of TLR2, TLR3, TLR7, TLR8 and TLR9, in cytobrush collected endocervical cells of 63 women diagnosed with CIN2 at study entry (baseline) and followed over a 3-year period. Wilcoxon rank-sum test was used to examine the association between TLR expression levels, measured at baseline, and CIN2 outcome (regression vs. persistence/progression) over time. HPV genotyping was performed using Roche Linear Array Assay detecting 37 HPV types. Women with CIN2 regression showed significantly higher baseline levels of TLR2 (p = 0.006) and TLR7 (p = 0.007), as well as a non-significant trend for a higher TLR8 expression (p = 0.053) compared to women with CIN2 persistence/progression. Six women with CIN2 regression, who presented with an HR-HPV DNA-negative CIN2 lesion at study entry, had significantly higher baseline levels of TLR2 (p = 0.005), TLR7 (p = 0.013) and TLR8 (p = 0.012), compared to women with CIN2 persistence/progression, suggesting their role in clearance of HPV prior to clearance of the lesion. Our results confirm a key role of TLRs in regression of CIN2 and support the potential use of TLR-agonists for treatment of these lesions.

Diakowska D, Nienartowicz M, Grabowski K, et al.
Toll-like receptors TLR-2, TLR-4, TLR-7, and TLR-9 in tumor tissue and serum of the patients with esophageal squamous cell carcinoma and gastro-esophageal junction cancer.
Adv Clin Exp Med. 2019; 28(4):515-522 [PubMed] Related Publications
BACKGROUND: Stimulation of toll-like receptors (TLRs) has been linked to the development of esophageal and gastric cancers.
OBJECTIVES: The aim of the study was to evaluate the clinical significance of tissue expression and serum concentration of TLR-2, TLR-4, TLR-7 and TLR-9 in patients with esophageal squamous cell carcinoma and gastro-esophageal junction adenocarcinoma.
MATERIAL AND METHODS: The study group consisted of 97 individuals: 32 with esophageal squamous cell carcinoma, 27 with gastro-esophageal junction cancer, and 38 ageand gender-matched controls. The mRNA expression and protein concentration of TLRs in tissues and sera were measured by reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) tests.
RESULTS: In esophageal cancer patients, mRNA expressions of TLR-2, TLR-4 and TLR-7, and protein concentrations of all TLRs were significantly higher in tumor than in control tissue (p < 0.05). In esophageal cancer patients with lymph node metastasis, a tendency toward higher protein concentrations of tumor TLR-4 was observed. In gastro-esophageal junction adenocarcinoma subgroup, only the mRNA expression of TLR-7 and protein concentrations of TLR-4, TLR-7 and TLR-9 were significantly higher in tumors than in normal mucosa (p < 0.05). Protein concentration of TLR-9 was significantly higher in tumors of gastro-esophageal junction cancer with lymph node metastasis and depth of tumor invasion. Diagnostic potential of serum TLR-4 as a marker of gastro-esophageal junction cancer presence was reported.
CONCLUSIONS: We demonstrated differences in the expression patterns of TLRs between esophageal squamous cell carcinoma and adenocarcinoma of gastro-esophageal junction, and showed circulating TLR-4 to be a potential marker of gastro-esophageal junction cancer.

Wang D, Jiang W, Zhu F, et al.
Modulation of the tumor microenvironment by intratumoral administration of IMO-2125, a novel TLR9 agonist, for cancer immunotherapy.
Int J Oncol. 2018; 53(3):1193-1203 [PubMed] Related Publications
The objective of cancer immunotherapy is to prime the host's immune system to recognize and attack malignant tumor cells. IMO‑2125, a Toll‑like receptor 9 (TLR9) agonist, exhibited potent antitumor effects in the murine syngeneic A20 lymphoma and the CT26 colon carcinoma models. IMO‑2125 exhibited superior A20 antitumor activity when injected intratumorally (i.t.) compared with equivalent subcutaneous doses. In mice bearing dual CT26 grafts, the i.t. injection of right flank tumors elicited infiltration of cluster of differentiation (CD)3+ T lymphocytes into tumors, resulting in the regression of injected and uninjected left flank tumors. Depletion of CD8+, but not CD4+, T‑cells abrogated the IMO‑2125‑mediated antitumor response, suggesting that CD8+ lymphocytes are required for the antitumor activity. In mice harboring right flank CT26 and left flank β‑galactosidase (β‑gal)‑expressing CT26.CL25 grafts, the i.t. administration of IMO‑2125 to the CT26 graft resulted in potent and dose‑dependent antitumor activity against the two grafts. Splenic T‑cells isolated from these mice responded to AH1 antigen (present in the two tumors) and β‑gal antigen (present only in CT26.CL25) in an interferon γ enzyme‑linked immunospot assay, suggesting the clonal expansion of T‑cells directed against antigens from the two tumors. Mice with ablated CT26 tumors by previous IMO‑2125 treatment rejected re‑implanted CT26 tumor cells, but not A20 tumor cells, demonstrating that the initial IMO‑2125 treatment created a long‑lived tumor‑specific immune memory of CT26 antigens. A quantitative increase in CD3+ T lymphocytes in injected A20 tumors and an upregulation of selected checkpoint genes, including indoleamine 2,3‑dioxygenase (IDO)‑1, IDO‑2, programmed cell death protein-1 (PD-1); programmed cell death protein ligand 1 (PD-L1), carcinoembryonic antigen‑related cell adhesion molecule 1, tumor necrosis factor receptor superfamily member 4 (OX40), OX40 ligand, T‑cell immunoglobulin and mucin‑domain‑containing 3 protein, lymphocyte‑activation gene 3, cytotoxic T‑lymphocyte‑associated protein 4, were observed following IMO‑2125 treatment. IMO‑2125 also increased immune checkpoint gene expression in injected and uninjected contralateral CT26 tumors, suggesting that the co‑administration of anti‑CTLA‑4, anti‑PD‑1 or anti‑PD‑L1 therapies with IMO‑2125 may provide additional therapeutic efficacy.

Phelan JD, Young RM, Webster DE, et al.
A multiprotein supercomplex controlling oncogenic signalling in lymphoma.
Nature. 2018; 560(7718):387-391 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
B cell receptor (BCR) signalling has emerged as a therapeutic target in B cell lymphomas, but inhibiting this pathway in diffuse large B cell lymphoma (DLBCL) has benefited only a subset of patients

Messaritakis I, Stogiannitsi M, Koulouridi A, et al.
Evaluation of the detection of Toll-like receptors (TLRs) in cancer development and progression in patients with colorectal cancer.
PLoS One. 2018; 13(6):e0197327 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
BACKGROUND: Toll-like receptors (TLRs) play essential role in innate and acquired immunity, are expressed in various cell types, and are associated with altered susceptibility to many diseases, and cancers. The aim of this study was to investigate TLR2 (-196 to-174del), TLR4 (Asp299Gly and Thr399Ile) and TLR9 (T1237C and T1486C) gene polymorphisms at risk of colorectal cancer (CRC) development and progression.
METHODS: Peripheral blood was obtained from 397 patients with adjuvant (stage II/III, n = 202) and metastatic (n = 195) CRC. Moreover, blood samples from 50 healthy volunteers and 40 patients with adenomatous polyps were also included as control groups. DNA from patients and controls was analyzed using PCR and PCR-RFLP for genotyping functional polymorphism within TLR2, TLR4 and TLR9 genotypes.
RESULTS: TLR2-196 to-174del/del genotype was detected in 76.6% of the patients and was significantly higher that the controls groups (p<0.001). TLR4 Asp299Gly, TLR4 Thr399Ile, TLR9 T1237C and T1486C homozygous genotypes were detected in 70.5%, 70.5%, 61.5% and 61.5% of the patients respectively, and were also significantly higher than that in the control groups (p<0.001). All polymorphisms detected were also significantly associated with the metastatic disease (p<0.001) leading to shorter overall survival (p<0.001); whereas, TLR4 Asp299Gly and Thr399Ile polymorphisms were significantly associated with KRAS mutations.
CONCLUSIONS: The detection of higher frequencies of the TLR2, TLR4 and/or TLR9 polymorphisms in CRC patients compared with the control groups highlight the role of these polymorphism in CRC development and cancer progression.

Temizoz B, Kuroda E, Ishii KJ
Combination and inducible adjuvants targeting nucleic acid sensors.
Curr Opin Pharmacol. 2018; 41:104-113 [PubMed] Related Publications
Innate immune sensing of nucleic acids derived from invading pathogens or tumor cells via pattern recognition receptors is crucial for mounting protective immune responses against infectious disease and cancer. Recently, discovery of tremendous amounts of nucleic acid sensors as well as identification of natural and synthetic ligands for these receptors revealed the potential of adjuvants targeting nucleic acid sensing pathways for designing efficacious vaccines. Especially, current data indicated that unique adjuvants targeting TLR9 and stimulator of interferon genes (STING)-dependent cytosolic nucleic acid sensing pathways along with the combinations of already existing adjuvants are promising candidates for this purpose. Here, we review current vaccine adjuvants targeting nucleic acid sensors and their modes of action.

Anunobi R, Boone BA, Cheh N, et al.
Extracellular DNA promotes colorectal tumor cell survival after cytotoxic chemotherapy.
J Surg Res. 2018; 226:181-191 [PubMed] Related Publications
BACKGROUND: Inflammation promotes the growth and survival of malignant cells. Inflammation within the tumor microenvironment is a result of damage-associated molecular patterns released by dead or dying cells that provide survival signals to the surrounding cells. It has been proposed that extracellular DNA can act as a damage-associated molecular pattern given the association between circulating DNA and autoimmune diseases. Herein, we demonstrate a novel role for genomic extracellular DNA binding to the Toll-like receptor (TLR)-9 on tumor cells in response to cytotoxic insult.
MATERIALS AND METHODS: The colorectal tumor cell line HCCT116 was used to study the role of DNA in tumor cell response to chemotherapy. Cell viability was assessed using CCK-8 assay. Cell death mechanisms were assessed by YOYO-1 and lactate dehydrogenase staining for necrosis and TUNEL staining for apoptosis. Autophagy was measured by LC3 punctate formation. TLR9-short hairpin RNA was used to knockdown TLR-9 and determine its role in tumor cell response to DNA.
RESULTS: DNA is released from necrotic tumor cells after chemotherapy. Survival after cytotoxic insult is enhanced by the presence of extracellular DNA as a result of inhibition of apoptosis and enhanced autophagy. Knockdown of TLR-9 enhanced apoptosis, diminished autophagy, and decreased survival after cytotoxic insult in the presence or absence of extracellular DNA.
CONCLUSIONS: DNA in the tumor microenvironment promotes survival through induction of autophagy via TLR-9 signaling. This work has important implications for targeting extracellular DNA, TLR-9, and autophagy during treatment with chemotherapy and enhances our understanding of the role of extracellular DNA in the tumor microenvironment.

Zhao X, Zhang Z, Moreira D, et al.
B Cell Lymphoma Immunotherapy Using TLR9-Targeted Oligonucleotide STAT3 Inhibitors.
Mol Ther. 2018; 26(3):695-707 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Growing evidence links the aggressiveness of non-Hodgkin's lymphoma, especially the activated B cell-like type diffuse large B cell lymphomas (ABC-DLBCLs) to Toll-like receptor 9 (TLR9)/MyD88 and STAT3 transcription factor signaling. Here, we describe a dual-function molecule consisting of a clinically relevant TLR9 agonist (CpG7909) and a STAT3 inhibitor in the form of a high-affinity decoy oligodeoxynucleotide (dODN). The CpG-STAT3dODN blocked STAT3 DNA binding and activity, thus reducing expression of downstream target genes, such as MYC and BCL2L1, in human and mouse lymphoma cells. We further demonstrated that injections (i.v.) of CpG-STAT3dODN inhibited growth of human OCI-Ly3 lymphoma in immunodeficient mice. Moreover, systemic CpG-STAT3dODN administration induced complete regression of the syngeneic A20 lymphoma, resulting in long-term survival of immunocompetent mice. Both TLR9 stimulation and concurrent STAT3 inhibition were critical for immune-mediated therapeutic effects, since neither CpG7909 alone nor CpG7909 co-injected with unconjugated STAT3dODN extended mouse survival. The CpG-STAT3dODN induced expression of genes critical to antigen-processing/presentation and Th1 cell activation while suppressing survival signaling. These effects resulted in the generation of lymphoma cell-specific CD8/CD4-dependent T cell immunity protecting mice from tumor rechallenge. Our results suggest that CpG-STAT3dODN as a systemic/local monotherapy or in combination with PD1 blockade can provide an opportunity for treating patients with B cell NHL.

Lange A, Jaskula E, Lange J, et al.
The sorafenib anti-relapse effect after alloHSCT is associated with heightened alloreactivity and accumulation of CD8+PD-1+ (CD279+) lymphocytes in marrow.
PLoS One. 2018; 13(1):e0190525 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
We studied three FLT3 ITD acute myeloid leukemia (AML) patients who relapsed after allogeneic haematopoietic stem cell transplantation (alloHSCT) and received multikinase inhibitor (MKI) sorafenib as part of salvage therapy. MKI was given to block the effect of FLT3 ITD mutation which powers proliferation of blast cells. However, the known facts that sorafenib is more effective in patents post alloHSCT suggested that this MKI can augment the immune system surveillance on leukaemia. In the present study, we investigated in depth the effect of sorafenib on the alloreactivity seen post-transplant including that on leukaemia. The patients (i) responded to the treatment with cessation of blasts which lasted 1, 17 and 42+ months, (ii) developed skin lesions with CD3+ cell invasion of the epidermis, (iii) had marrow infiltrated with CD8+ lymphocytes which co-expressed PD-1 (programmed cell death protein 1 receptor, CD279) in higher proportions than those in the blood (163±32 x103 cells/μl vs 38±8 x103 cells/μl, p<0.001). The Lymphoprep fraction of marrow cells investigated for the expression of genes involved in lymphocyte activation showed in the patients with long lasting complete remission (CR) a similar pattern characterized by (i) a low expression of nitric oxide synthase 2 (NOS2) and colony stimulating factor 2 (CSF2) as well as that of angiopoietin-like 4 (ANGPTL4) (supporting the immune response and anti-angiogenic) genes, and (ii) higher expression of fibroblast growth factor 1 (FGF1) and collagen type IV alpha 3 chain (COL4A3) as well as toll like receptor 9 (TLR9) and interleukin-12 (IL-12) (pro-inflammatory expression profile) genes as compared with the normal individual. The positive effect in one patient hardly justified the presence of unwanted effects (progressive chronic graft-versus-host disease (cGvHD) and avascular necrosis of the femur), which were in contrast negligible in the other patient. The anti-leukemic and unwanted effects of sorafenib do not rely on each other.

Ali YB, Foad RM, Abdel-Wahed E
Lack of Associations between TLR9 and MYD88 Gene Polymorphisms and Risk of Chronic Lymphocytic Leukemia
Asian Pac J Cancer Prev. 2017; 18(12):3245-3250 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Background: Genetic factors like single nucleotide polymorphisms (SNPs) may play an important role in the etiology of chronic lymphocytic leukemia (CLL). Mutations in Toll like receptor 9 (TLR9) and myeloid differentiation primary response 88 (MYD88) genes may lead to an abnormal immune response that may cause greater cell proliferation and thus alter an individual’s susceptibility to haematological malignancies including CLL. Objective: This work was designed to study any association of the TLR9 (rs2066807C/G and rs187084T/C) and MYD88 (L265P) single nucleotide polymorphism (SNPs) with risk of CLL in Egyptians. Materials and methods: One hundred patients with CLL and 100 healthy controls from the Egyptian population were genotyped by the polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) method. Results: With TLR9 rs2066807C/G the CC genotype was more frequent in both control and patient groups while for TLR9 rs187084T/C the TT genotype was most common. There were no significant associations with CLL risk. With MYD88 (L265P) only the TT genotype was detected. Conclusion: Our preliminary data suggest that polymorphisms in the TLR9 and MYD88 genes may not contribute to CLL susceptibility. To the best of our knowledge, this study is the first dealing with TLR9 and MYD88 gene polymorphisms in CLL patients. Further studies with larger sample size should be conducted to validate these results in the Egyptian population.

Jordi M, Marty J, Mordasini V, et al.
IRAK4 is essential for TLR9-induced suppression of Epstein-Barr virus BZLF1 transcription in Akata Burkitt's lymphoma cells.
PLoS One. 2017; 12(10):e0186614 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Burkitt's lymphoma (BL) is the most common childhood cancer in equatorial Africa, and is endemic to areas where people are chronically co-infected with Epstein-Barr virus (EBV) and the malaria pathogen Plasmodium falciparum. The contribution of these pathogens in the oncogenic process remains poorly understood. We showed earlier that the activation of Toll-like receptor (TLR) 9 by hemozoin, a disposal product formed from the digestion of blood by P. falciparum, suppresses the lytic reactivation of EBV in BL cells. EBV lytic reactivation is regulated by the expression of transcription factor Zta (ZEBRA), encoded by the EBV gene BZLF1. Here, we explore in the BL cell line Akata, the mechanism involved in repression by TLR9 of expression of BZLF1. We show that BZLF1 repression is mediated upon TLR9 engagement by a mechanism that is largely independent of de novo protein synthesis. By CRISPR/Cas9-induced inactivation of TLR9, MyD88, IRAK4 and IRAK1 we confirm that BZLF1 repression is dependent on functional TLR9 and MyD88 signaling, and identify IRAK4 as an essential element for TLR9-induced repression of BZLF1 expression upon BCR cross-linking. Our results unprecedentedly show that TLR9-mediated inhibition of lytic EBV is largely independent of new protein synthesis and demonstrate the central roles of MyD88 and IRAK4 in this process contributing to EBV's persistence in the host's B-cell pool.

Jang D, Baek YM, Park H, et al.
Dual effects of a CpG-DNAzyme targeting mutant EGFR transcripts in lung cancer cells: TLR9 activation and EGFR downregulation.
BMB Rep. 2018; 51(1):27-32 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Non-small-cell lung cancer (NSCLC) is commonly caused by a mutation in the epidermal growth factor receptor (EGFR) and subsequent aberrant EGFR signaling with uncontrolled kinase activity. A deletion mutation in EGFR exon 19 is frequently observed in EGFR gene mutations. We designed a DNAzyme to suppress the expression of mutant EGFR by cleaving the mutant EGFR mRNA. The DNAzyme (named Ex19del Dz) specifically cleaved target RNA and decreased cancer cell viability when transfected into gefitinib-resistant lung cancer cells harboring EGFR exon 19 deletions. The DNAzyme decreased EGFR expression and inhibited its downstream signaling pathway. In addition to EGFR downregulation, Ex19del Dz containing CpG sites activated Toll-like receptor 9 (TLR9) and its downstream signaling pathway via p38 kinase, causing an immunostimulatory effect on EGFR-mutated NSCLC cells. Thus, dual effects of this DNAzyme harboring the CpG site, such as TLR9 activation and EGFR downregulation, leads to apoptosis of EGFR-mutated NSCLC cells. [BMB Reports 2018; 51(1): 27-32].

Chandler MR, Keene KS, Tuomela JM, et al.
Lower frequency of TLR9 variant associated with protection from breast cancer among African Americans.
PLoS One. 2017; 12(9):e0183832 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
INTRODUCTION: Toll-like receptor 9 (TLR9) is an innate immune system DNA-receptor that regulates tumor invasion and immunity in vitro. Low tumor TLR9 expression has been associated with poor survival in Caucasian patients with triple negative breast cancer (TNBC). African American (AA) patients with TNBC have worse prognosis than Caucasians but whether this is due to differences in tumor biology remains controversial. We studied the prognostic significance of tumor Toll like receptor-9 (TLR9) protein expression among African American (AA) triple negative breast cancer (TNBC) patients. Germline TLR9 variants in European Americans (EAs) and AAs were investigated, to determine their contribution to AA breast cancer risk.
METHODS: TLR9 expression was studied with immunohistochemistry in archival tumors. Exome Variant Server and The Cancer Genome Atlas were used to determine the genetic variation in the general EA and AA populations, and AA breast cancer cases. Minor allele frequencies (MAFs) were compared between EAs (n = 4300), AAs (n = 2203), and/or AA breast cancer cases (n = 131).
RESULTS: Thirty-two TLR9 variants had a statistically significant MAF difference between general EAs and AAs. Twenty-one of them affect a CpG site. Rs352140, a variant previously associated with protection from breast cancer, is more common in EAs than AAs (p = 2.20E-16). EAs had more synonymous alleles, while AAs had more rare coding alleles. Similar analyses comparing AA breast cancer cases with AA controls did not reveal any variant class differences; however, three previously unreported TLR9 variants were associated with late onset breast cancer. Although not statistically significant, rs352140 was observed less frequently in AA cases compared to controls. Tumor TLR9 protein expression was not associated with prognosis.
CONCLUSIONS: Tumor TLR9 expression is not associated with prognosis in AA TNBC. Significant differences were detected in TLR9 variant MAFs between EAs and AAs. They may affect TLR9 expression and function. Rs352140, which may protect from breast cancer, is 1.6 X more common among EAs. These findings call for a detailed analysis of the contribution of TLR9 to breast cancer pathophysiology and health disparities.

Poe JC, Jia W, Su H, et al.
An aberrant NOTCH2-BCR signaling axis in B cells from patients with chronic GVHD.
Blood. 2017; 130(19):2131-2145 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
B-cell receptor (BCR)-activated B cells contribute to pathogenesis in chronic graft-versus-host disease (cGVHD), a condition manifested by both B-cell autoreactivity and immune deficiency. We hypothesized that constitutive BCR activation precluded functional B-cell maturation in cGVHD. To address this, we examined BCR-NOTCH2 synergy because NOTCH has been shown to increase BCR responsiveness in normal mouse B cells. We conducted ex vivo activation and signaling assays of 30 primary samples from hematopoietic stem cell transplantation patients with and without cGVHD. Consistent with a molecular link between pathways, we found that BCR-NOTCH activation significantly increased the proximal BCR adapter protein BLNK. BCR-NOTCH activation also enabled persistent NOTCH2 surface expression, suggesting a positive feedback loop. Specific NOTCH2 blockade eliminated NOTCH-BCR activation and significantly altered NOTCH downstream targets and B-cell maturation/effector molecules. Examination of the molecular underpinnings of this "NOTCH2-BCR axis" in cGVHD revealed imbalanced expression of the transcription factors

Martínez-Campos C, Bahena-Román M, Torres-Poveda K, et al.
TLR9 gene polymorphism -1486T/C (rs187084) is associated with uterine cervical neoplasm in Mexican female population.
J Cancer Res Clin Oncol. 2017; 143(12):2437-2445 [PubMed] Related Publications
PURPOSE: The aim of this work was to evaluate the association of single nucleotide polymorphisms in TLR9 (-1486 T/C [rs187084], -1237T/C [rs5743836] and G2848A [rs352140]) with HPV infection, squamous intraepithelial lesions, and uterine cervical neoplasm in a Mexican population. Additionally, the peripheral expression of TLR9 was evaluated to evaluate the differences in the TLR9 expression associated with every genotype in the locus -1486 of the TLR9 gene. The serum concentration of TLR9 was evaluated in a randomly selected subsample.
METHODS: Genotyping was performed using predesigned 5' endonuc lease assays and the association of the polymorphisms with the diagnosis groups were assessed by performing multinomial regression models. The relative expression of TLR9 in peripheral blood mononuclear cells was evaluated by real-time polymerase chain reaction and the association of the level of TLR9 expression with the diagnosis was evaluated by performing multinomial regression models. The serum concentration of TLR9 was evaluated in a subsample of patients diagnosed with uterine cervical neoplasm by ELISA.
RESULTS: The results showed that genotype TT in the -1486 locus of TLR9 was significantly associated with HPV infection (OR = 3.25, 95% CI 1.12-9.46), squamous intraepithelial cervical lesion (OR = 3.76, 95% CI 1.36-10.41), and uterine cervical neoplasm (OR = 5.30, 95% CI 1.81-15.55). Moreover, the highest level of TLR9 expression was significantly associated with a greater risk for developing squamous intraepithelial cervical lesion and uterine cervical neoplasm. The serum TLR9 concentration was higher in patients with uterine cervical cancer than in controls.
CONCLUSION: Our findings indicate that genotype TT in the -1486 locus of the TLR9 gene could comprise a risk genotype for HPV infection, squamous intraepithelial cervical lesion, and uterine cervical neoplasm in Mexican female population. Further studies with larger samples are needed to evaluate if the peripheral expression of TLR9 could be used as a biomarker of uterine cervical neoplasm progression.

Fonte E, Vilia MG, Reverberi D, et al.
Toll-like receptor 9 stimulation can induce IκBζ expression and IgM secretion in chronic lymphocytic leukemia cells.
Haematologica. 2017; 102(11):1901-1912 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Chronic lymphocytic leukemia cells strongly depend on external stimuli for their survival. Both antigen receptor and co-stimulatory receptors, including Toll-like receptors, can modulate viability and proliferation of leukemic cells. Toll-like receptor ligands, and particularly the TLR9 ligand CpG, mediate heterogeneous responses in patients' samples reflecting the clinical course of the subjects. However, the molecular framework of the key signaling events underlying such heterogeneity is undefined. We focused our studies on a subset of chronic lymphocytic leukemia cases characterized by expression of CD38 and unmutated immunoglobulin genes, who respond to CpG with enhanced metabolic cell activity. We report that, while CpG induces

Pacini L, Ceraolo MG, Venuti A, et al.
UV Radiation Activates Toll-Like Receptor 9 Expression in Primary Human Keratinocytes, an Event Inhibited by Human Papillomavirus 38 E6 and E7 Oncoproteins.
J Virol. 2017; 91(19) [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Several lines of evidence indicate that cutaneous human papillomavirus (HPV) types belonging to the beta genus of the HPV phylogenetic tree synergize with UV radiation in the development of skin cancer. Accordingly, the E6 and E7 oncoproteins from some beta HPV types are able to deregulate pathways related to immune response and cellular transformation. Toll-like receptor 9 (TLR9), in addition to playing a role in innate immunity, has been shown to be involved in the cellular stress response. Using primary human keratinocytes as experimental models, we have shown that UV irradiation (and other cellular stresses) activates TLR9 expression. This event is closely linked to p53 activation. Silencing the expression of p53 or deleting its encoding gene affected the activation of TLR9 expression after UV irradiation. Using various strategies, we have also shown that the transcription factors p53 and c-Jun are recruited onto a specific region of the TLR9 promoter after UV irradiation. Importantly, the E6 and E7 oncoproteins from beta HPV38, by inducing the accumulation of the p53 antagonist ΔNp73α, prevent the UV-mediated recruitment of these transcription factors onto the TLR9 promoter, with subsequent impairment of TLR9 gene expression. This study provides new insight into the mechanism that mediates TLR9 upregulation in response to cellular stresses. In addition, we show that HPV38 E6 and E7 are able to interfere with this mechanism, providing another explanation for the possible cooperation of beta HPV types with UV radiation in skin carcinogenesis.

Doorduijn EM, Sluijter M, Salvatori DC, et al.
Cancer Immunol Res. 2017; 5(8):642-653 [PubMed] Related Publications
One of the next challenges in cancer immunotherapy is the resistance of tumors to T-cell-based treatments through loss of MHC class I. Here, we show that under these circumstances, the Toll-like receptor (TLR)-7/8 ligand imiquimod, but not the TLR3 ligand poly I:C or TLR9 ligand CpG, mediated an effective antitumor response. The rejection of these immune-escaped cancers was mediated by NK cells and CD4

Uzonyi B, Mácsik-Valent B, Lukácsi S, et al.
Functional studies of chronic lymphocytic leukemia B cells expressing β
Immunol Lett. 2017; 189:73-81 [PubMed] Related Publications
The expression and role of CR3 (CD11b/CD18) and CR4 (CD11c/CD18) in B cells are not yet explored in contrast to myeloid cells, where these β

Won H, Moreira D, Gao C, et al.
TLR9 expression and secretion of LIF by prostate cancer cells stimulates accumulation and activity of polymorphonuclear MDSCs.
J Leukoc Biol. 2017; 102(2):423-436 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Proinflammatory signals promote prostate tumorigenesis and progression, but their origins and downstream effects remain unclear. We recently demonstrated that the expression of an innate immune receptor, TLR9, by prostate cancer cells is critical for their tumor-propagating potential. We investigated whether cancer cell-intrinsic TLR9 signaling alters composition of the prostate tumor microenvironment. We generated Ras/Myc (RM9) and Myc-driven (Myc-CaP) prostate cancer cells expressing the tetracycline-inducible gene

Jin Y, Qiu S, Shao N, Zheng J
Association of toll-like receptor gene polymorphisms and its interaction with HPV infection in determining the susceptibility of cervical cancer in Chinese Han population.
Mamm Genome. 2017; 28(5-6):213-219 [PubMed] Related Publications
The aim of the study is to investigate the association of several single-nucleotide polymorphisms (SNPs) within Toll-like receptors (TLRs) gene and additional gene-gene and gene-human papillomavirus (HPV) infection interaction with cervical cancer risk. A total of 1262 participants are selected, including 420 cervical cancer patients and 842 control participants. Generalized multifactor dimensionality reduction (GMDR) was used to screen the best interaction combination among five SNPs within TLR gene and HPV infection. Logistic regression was performed to calculate the ORs (95 %CI) for association of five SNPs within TLR gene and additional gene-HPV infection interaction with cervical cancer risk. Cervical cancer risk was significantly higher in carriers of the T allele of rs3775290 within TLR2 gene, the G allele of rs7873784 within TLR4 gene, and the A allele of rs352140 within TLR9 gene than those with wild genotype; adjusted ORs (95 %CI) were 1.78 (1.20-2.24), 1.65 (1.23-2.12), and 1.70 (1.16-2.31). However, we did not find any significant association of rs4986791 and rs11536889 with cervical cancer risk. GMDR analysis suggested a significant two-locus model (p = 0.0107) involving rs352140 and HPV infection. Subjects with HPV infection and rs352140-GA + AA genotype within TLR9 gene have the highest cervical cancer risk, compared to no HPV infection participants with rs352140-GG genotype, OR (95 %CI) = 3.22 (1.68-4.81). Pairwise LD analysis did not find any significant haplotype combination associated with cervical cancer risk. The minor alleles of TLR2-rs3775290, TLR4-rs7873784, and TLR9-rs352140, and interaction between rs352140 and HPV infection were all associated with increased cervical cancer risk.

Sen S, Mandal P, Bhattacharya A, et al.
Impact of viral and host DNA methylations on HPV16-related cervical cancer pathogenesis.
Tumour Biol. 2017; 39(5):1010428317699799 [PubMed] Related Publications
Epigenetic alterations within human papillomavirus (HPV) and host cellular genomes are known to occur during cervical carcinogenesis. Our objective was to analyse the influence of (1) methylation within two immunostimulatory CpG motifs within HPV16 E6 and E7 genes around the viral late promoter and their correlation, if any, with expression deregulation of host receptor (TLR9) and DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) and (2) global DNA methylation levels within CpGs of the repetitive Alu sequences, on cervical cancer (CaCx) pathogenesis. Significantly higher proportions of CaCx samples portrayed methylation in immunostimulatory CpG motifs, compared to HPV16-positive non-malignant samples, with cases harbouring episomal HPV16 showing decreased methylation compared to those with viral integration. A significant linear trend of TLR9 upregulation was recorded in the order of HPV-negative controls < HPV16-positive non-malignant samples < HPV16-positive CaCx cases. TLR9 upregulation in cases with episomal HPV16 was again higher among those with non-methylated immunostimulatory CpG motifs. Comparison of cases with HPV-negative controls revealed that DNMT3A was significantly downregulated only among integrated cases, DNMT3B was significantly overexpressed among both categories of cases, although at variable levels, while DNMT1 failed to show any deregulated expression among the cases. Global host DNA hypomethylation, also showed a significant linear increasing trend through the progressive CaCx development stages mentioned above and was most prominently higher among cases with episomal HPV16 as opposed to viral integration. Thus, HPV16 and host methylations appear to influence CaCx pathogenesis, with differential molecular signatures among CaCx cases with episomal and integrated HPV16.

Bouillez A, Rajabi H, Jin C, et al.
MUC1-C integrates PD-L1 induction with repression of immune effectors in non-small-cell lung cancer.
Oncogene. 2017; 36(28):4037-4046 [PubMed] Article available free on PMC after 01/12/2019 Related Publications
Immunotherapeutic approaches, particularly programmed death 1/programmed death ligand 1 (PD-1/PD-L1) blockade, have improved the treatment of non-small-cell lung cancer (NSCLC), supporting the premise that evasion of immune destruction is of importance for NSCLC progression. However, the signals responsible for upregulation of PD-L1 in NSCLC cells and whether they are integrated with the regulation of other immune-related genes are not known. Mucin 1 (MUC1) is aberrantly overexpressed in NSCLC, activates the nuclear factor-κB (NF-κB) p65→︀ZEB1 pathway and confers a poor prognosis. The present studies demonstrate that MUC1-C activates PD-L1 expression in NSCLC cells. We show that MUC1-C increases NF-κB p65 occupancy on the CD274/PD-L1 promoter and thereby drives CD274 transcription. Moreover, we demonstrate that MUC1-C-induced activation of NF-κB→︀ZEB1 signaling represses the TLR9 (toll-like receptor 9), IFNG, MCP-1 (monocyte chemoattractant protein-1) and GM-CSF genes, and that this signature is associated with decreases in overall survival. In concert with these results, targeting MUC1-C in NSCLC tumors suppresses PD-L1 and induces these effectors of innate and adaptive immunity. These findings support a previously unrecognized central role for MUC1-C in integrating PD-L1 activation with suppression of immune effectors and poor clinical outcome.

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