Toll-like receptor 9 agonists promote cellular invasion by increasing matrix metalloproteinase activity

Understanding the Role of Toll-Like Receptors 9 in Breast Cancer

Breast cancer is a significant global issue, ranking as the second most common cancer among women worldwide and a leading cause of cancer-related deaths. Although the exact causes of this increase remain unclear, factors such as genetics, epigenetics, obesity, sedentary lifestyle, tobacco use, and vitamin D deficiency have been implicated. The Toll-like receptor 9 (TLR9) is recognized for its role in inflammation and innate immunity; however, its specific involvement in breast cancer pathogenesis requires further investigation. This study aims to systematically review the existing literature on TLR9 expression in normal and cancerous breast tissue, providing current knowledge and identifying gaps. Relevant articles in English were from PubMed, Scopus, and Google Scholar, with the inclusion criteria focusing on studies evaluating TLR9 mRNA and protein expression. The review found that TLR9 mRNA and protein exhibit variable expressions in both normal and cancerous breast tissue, highlighting the need for further research to clarify TLR9's role in breast cancer.

Toll-like receptors in breast cancer immunity and immunotherapy

Toll-like receptors (TLRs) are a key family of pattern recognition receptors (PRRs) in the innate immune system. The activation of TLRs will not only prevent pathogen infection but also respond to damage-induced danger signaling. Increasing evidence suggests that TLRs play a critical role in breast cancer development and treatment. However, the activation of TLRs is a double-edged sword that can induce either pro-tumor activity or anti-tumor effect. The underlying mechanisms of these opposite effects of TLR signaling in cancer are not fully understood. Targeting TLRs is a promising strategy for improving breast cancer treatment, either as monotherapies or by improving other current therapies. Here we provide an update on the role of TLRs in breast cancer immunity and immunotherapy.

Harnessing innate immune pathways for therapeutic advancement in cancer

The innate immune pathway is receiving increasing attention in cancer therapy. This pathway is ubiquitous across various cell types, not only in innate immune cells but also in adaptive immune cells, tumor cells, and stromal cells. Agonists targeting the innate immune pathway have shown profound changes in the tumor microenvironment (TME) and improved tumor prognosis in preclinical studies. However, to date, the clinical success of drugs targeting the innate immune pathway remains limited. Interestingly, recent studies have shown that activation of the innate immune pathway can paradoxically promote tumor progression. The uncertainty surrounding the therapeutic effectiveness of targeted drugs for the innate immune pathway is a critical issue that needs immediate investigation. In this review, we observe that the role of the innate immune pathway demonstrates heterogeneity, linked to the tumor development stage, pathway status, and specific cell types. We propose that within the TME, the innate immune pathway exhibits multidimensional diversity. This diversity is fundamentally rooted in cellular heterogeneity and is manifested as a variety of signaling networks. The pro-tumor effect of innate immune pathway activation essentially reflects the suppression of classical pathways and the activation of potential pro-tumor alternative pathways. Refining our understanding of the tumor's innate immune pathway network and employing appropriate targeting strategies can enhance our ability to harness the anti-tumor potential of the innate immune pathway and ultimately bridge the gap from preclinical to clinical application.

Clinical value of serum MMP-3 in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is defined as the progressive deterioration of renal parenchyma and decline in renal unit function. In the early stages of CKD(G1 + G2), symptoms are usually not obvious and cannot be effectively recognized on the basis of available clinical markers. Progression to the middle and late stages of CKD results in severe kidney damage with multiple complications causing adverse outcomes, including death. Therefore, the early diagnosis and monitoring of CKD is critical. Matrix metalloproteinase-3 (MMP-3), an extracellular matrix-degrading enzyme, plays an important role in kidney diseases. However, the clinical significance of serum MMP-3 levels in CKD has rarely been reported.

METHODS

We quantified the serum MMP-3 levels of 237 patients with CKD and 96 healthy individuals by using a highly sensitive time-resolved fluorescence immunoassay and analyzed differences in MMP-3 levels among the stages of CKD and the correlations of these changes with clinical indicators.

RESULTS

The serum MMP-3 concentrations of patients with CKD (171.76 ± 165.22 ng/mL) were significantly higher than those of healthy controls (34.05 ± 22.93 ng/mL; P < 0.0001). In CKD, serum MMP-3 levels were significantly correlated with estimated glomerular filtration rate (eGFR) (r =  - 0.5804, P < 0.0001), serum creatinine (CREA) (r = 0.5823, P < 0.0001), blood urea nitrogen (BUN) (r = 0.6106, P < 0.0001), and protein-to-creatinine ratio (r = 0.4992, P < 0.0001). Randomized forest analysis finds CREA, BUN, and MMP-3 most significant influences on CKD disease severity. The critical value of MMP-3 concentration of 40.39 ng/mL combined with eGFR was effective in diagnosing positive patients in the early (G1 + G2) stage of CKD and showed a positivity rate of 73.45 %. Moreover, in the early stages of CKD, patients with CKD who had serum MMP-3 concentration > 100 ng/mL had more severe renal impairment and inflammation than those with CKD who have lower serum MMP-3 concentrations.

CONCLUSION

Elevated serum MMP-3 levels are correlated with decreased kidney function in CKD progression, and patients with concomitant inflammation may express high levels of serum MMP-3. Serum MMP-3 may assist eGFR in improving the diagnosis of patients with early CKD.

The Role of Progranulin (PGRN) in the Pathogenesis of Glioblastoma Multiforme

Glioblastoma multiforme (GBM) represents the most common and aggressive malignant form of brain tumour in adults and is characterized by an extremely poor prognosis with dismal survival rates. Currently, expanding concepts concerning the pathophysiology of GBM are inextricably linked with neuroinflammatory phenomena. On account of this fact, the identification of novel pathomechanisms targeting neuroinflammation seems to be crucial in terms of yielding successful individual therapeutic strategies. In recent years, the pleiotropic growth factor progranulin (PGRN) has attracted significant attention in the neuroscience and oncological community regarding its neuroimmunomodulatory and oncogenic functions. This review of the literature summarizes and updates contemporary knowledge about PGRN, its associated receptors and signalling pathway involvement in GBM pathogenesis, indicating possible cellular and molecular mechanisms with potential diagnostic, prognostic and therapeutic targets in order to yield successful individual therapeutic strategies. After a review of the literature, we found that there are possible PGRN-targeted therapeutic approaches for implementation in GBM treatment algorithms both in preclinical and future clinical studies. Furthermore, PGRN-targeted therapies exerted their highest efficacy in combination with other established chemotherapeutic agents, such as temozolomide. The results of the analysis suggested that the possible implementation of routine determinations of PGRN and its associated receptors in tumour tissue and biofluids could serve as a diagnostic and prognostic biomarker of GBM. Furthermore, promising preclinical applications of PGRN-related findings should be investigated in clinical studies in order to create new diagnostic and therapeutic algorithms for GBM treatment.

Harnessing the innate immune system by revolutionizing macrophage-mediated cancer immunotherapy

Immunotherapy is a promising and safer alternative to conventional cancer therapies. It involves adaptive T-cell therapy, cancer vaccines, monoclonal antibodies, immune checkpoint blockade (ICB), and chimeric antigen receptor (CAR) based therapies. However, most of these modalities encounter restrictions in solid tumours owing to a dense, highly hypoxic and immune-suppressive microenvironment as well as the heterogeneity of tumour antigens. The elevated intra-tumoural pressure and mutational rates within fastgrowing solid tumours present challenges in efficient drug targeting and delivery. The tumour microenvironment is a dynamic niche infiltrated by a variety of immune cells, most of which are macrophages. Since they form a part of the innate immune system, targeting macrophages has become a plausible immunotherapeutic approach. In this review, we discuss several versatile approaches (both at pre-clinical and clinical stages) such as the direct killing of tumour-associated macrophages, reprogramming pro-tumour macrophages to anti-tumour phenotypes, inhibition of macrophage recruitment into the tumour microenvironment, novel CAR macrophages, and genetically engineered macrophages that have been devised thus far. These strategies comprise a strong and adaptable macrophage-toolkit in the ongoing fight against cancer and by understanding their significance, we may unlock the full potential of these immune cells in cancer therapy.

Caffeic acid phenethyl ester inhibits MDA-MB-231 cell proliferation in inflammatory microenvironment by suppressing glycolysis and lipid metabolism

Caffeic acid phenethyl ester (CAPE) is one of the main active ingredients of propolis with good antitumor activities. However, the potential effects of CAPE on the glycolysis and lipid metabolism of tumor cells are unclear. Here, the anti-tumor effects of CAPE on MDA-MB-231 cells in an inflammatory microenvironment stimulated with lipopolysaccharide (LPS) were studied by estimating the inflammatory mediators and the key factors of glycolysis and lipid metabolism. The CAPE treatment obviously inhibited proliferation, migration, invasion, and angiogenesis, and the mitochondrial membrane potential was decreased in the LPS-stimulated MDA-MB-231 cells. Compared with the LPS group, pro-inflammatory mediators, including toll-like receptor 4 (TLR4), tumor necrosis factor alpha (TNF-α), NF-kappa-B inhibitor alpha (IκBα), interleukin (IL)-1β, and IL-6, as well as interleukin-1 receptor-associated kinase 4 (IRAK4), declined after the CAPE treatment. Additionally, CAPE significantly down-regulated the levels of glucose transporter 1 (GLUT1), glucose transporter 3 (GLUT3), and the key enzymes of glycolysis-hexokinase 2 (HK2), phosphofructokinase (PFK), pyruvate kinase muscle isozyme M2 (PKM2), and lactate dehydrogenase A (LDHA). Moreover, CAPE treatment decreased the levels of key lipid metabolism proteins, including acetyl coenzyme A carboxylase (ACC), fatty acid synthase (FASN), and free fatty acid (FFA)-transported-related protein CD36. After adding the glycolysis inhibitor 2-deoxy-D-glucose (2-DG), the inhibitory effects of CAPE on cell viability and migration were not significant when compared with the LPS group. In summary, the antitumor activity of CAPE in vitro was mainly via the modulation of the inflammatory mediators and the inhibition of key proteins and enzymes in glucose and lipid metabolism.

Hypoxic Effects on Matrix Metalloproteinases' Expression in the Tumor Microenvironment and Therapeutic Perspectives

The tumor microenvironment (TME) is characterized by an acidic pH and low oxygen concentrations. Hypoxia induces neoplastic cell evasion of the immune surveillance, rapid DNA repair, metabolic reprogramming, and metastasis, mainly as a response to the hypoxic inducible factors (HIFs). Likewise, cancer cells increase matrix metalloproteinases' (MMPs) expression in response to TME conditions, allowing them to migrate from the primary tumor to different tissues. Since HIFs and MMPs are augmented in the hypoxic TME, it is easy to consider that HIFs participate directly in their expression regulation. However, not all MMPs have a hypoxia response element (HRE)-HIF binding site. Moreover, different transcription factors and signaling pathways activated in hypoxia conditions through HIFs or in a HIF-independent manner participate in MMPs' transcription. The present review focuses on MMPs' expression in normal and hypoxic conditions, considering HIFs and a HIF-independent transcription control. In addition, since the hypoxic TME causes resistance to anticancer conventional therapy, treatment approaches using MMPs as a target alone, or in combination with other therapies, are also discussed.

Microbial sensing in the intestine

The gut microbiota plays a key role in host health and disease, particularly through their interactions with the immune system. Intestinal homeostasis is dependent on the symbiotic relationships between the host and the diverse gut microbiota, which is influenced by the highly co-evolved immune-microbiota interactions. The first step of the interaction between the host and the gut microbiota is the sensing of the gut microbes by the host immune system. In this review, we describe the cells of the host immune system and the proteins that sense the components and metabolites of the gut microbes. We further highlight the essential roles of pattern recognition receptors (PRRs), the G protein-coupled receptors (GPCRs), aryl hydrocarbon receptor (AHR) and the nuclear receptors expressed in the intestinal epithelial cells (IECs) and the intestine-resident immune cells. We also discuss the mechanisms by which the disruption of microbial sensing because of genetic or environmental factors causes human diseases such as the inflammatory bowel disease (IBD).

Elderly-Onset Rheumatoid Arthritis: Characteristics and Treatment Options

Elderly-onset rheumatoid arthritis (EORA) is a distinct clinical entity defined as the onset of rheumatoid arthritis (RA) in individuals aged over 60 years. EORA presents unique clinical features, including a more equitable distribution of sexes, a potential predilection for male involvement, a higher incidence of acute onset characterized by constitutional symptoms, a propensity for systemic manifestations, elevated sedimentation rates at disease onset, a reduced occurrence of rheumatoid factor positivity, increased titers of anti-citrullinated protein antibodies, a preference for involvement of large joints, elevated disease activity, the presence of bone erosions, and heightened patient disability. RA is recognized to consist of three partially overlapping subsets. One subset mirrors the classical RA clinical presentation, while the remaining subsets exhibit either a polymyalgia rheumatica-like phenotype or present with remitting seronegative symmetrical synovitis accompanied by pitting edema syndrome. In the initial stages of EORA management, non-steroidal anti-inflammatory drugs (NSAIDs) are not typically the first-line treatment choice, because seniors are much more prone to develop side effects due to NSAIDs, and the use of NSAIDs is in reality contraindicated to the majority of seniors due to comorbidities. Disease-modifying antirheumatic drugs (DMARDs), frequently methotrexate, are introduced immediately after the diagnosis is made. In cases where elderly patients demonstrate resistance to conventional DMARD therapy, the introduction of biological or targeted synthetic DMARDs becomes a viable treatment option. EORA presents a unique clinical profile, necessitating tailored treatment strategies. Our study emphasizes the challenges of NSAID use in seniors, highlighting the imperative shift toward DMARDs such as methotrexate. Future research should explore personalized DMARD approaches based on disease activity, comorbidities, and safety considerations, aiming to optimize treatment outcomes and minimize glucocorticoid reliance, thereby enhancing the quality of care for EORA patients.

Association of Hydroxychloroquine Use with a Dose-Dependent Decrease in Mortality Risk in Patients with Elderly-Onset Rheumatoid Arthritis

INTRODUCTION

Elderly-onset rheumatoid arthritis (EORA) is associated with an increased mortality risk; however, the effect of conventional synthetic, biologics or targeted synthetic disease-modifying anti-rheumatic drugs (csDMARDs, bDMARDs or tsDMARDs) on the EORA-specific mortality risk is unknown. In this study, we investigated the risk factors for all-cause mortality of patients with EORA.

METHODS

Data of EORA patients diagnosed with RA at age > 60 years between January 2007 and June 2021 were extracted from the electronic health record of Taichung Veterans General Hospital, Taiwan. Multivariable Cox regression was used to calculate the hazard ratio (HR) and 95% confidence interval (CI). The survival of patients with EORA was analyzed by Kaplan-Meier method.

RESULTS

Among the 980 EORA patients who were enrolled (survivors 852 and non-survivor 128), the significant mortality-associated risk factors [HR (95% CI)] included higher age (1.10 [1.07-1.12], p < 0.001), male sex (1.92 [1.22-3.00], p = 0.004), current smoker (2.31 [1.10-4.87], p = 0.027) and underlying malignancy (1.89 [1.20-2.97], p = 0.006). Hydroxychloroquine treatment conferred protection against mortality in patients with EORA (HR 0.30, 95% CI 0.14-0.64, p = 0.002). Patients with malignancy who did not receive hydroxychloroquine treatment had the highest mortality risk compared with their counterparts. Patients with a monthly cumulative dose of hydroxychloroquine dose < 1374.5 mg had the lowest survival rate compared to patients who received hydroxychloroquine 1374.5-5778.5 and ≥ 5778.5 mg.

CONCLUSION

Hydroxychloroquine treatment is associated with survival benefits in patients with EORA, and prospective studies are needed to validate the abovementioned findings.

TLRs expression in canine mammary gland neoplasms: a pathological and molecular study

TLRs are a class of PRRs that play a vital role in innate immunity. TLRs are expressed on immune cells and mammary epithelial cells. They can promote tumor growth, angiogenesis, invasion, and viability signaling. The current study aimed to test the correlation between histologic types and grades of neoplasms and TLRs gene expression levels. Twenty-one tissue samples of canine mammary neoplasms were stained with H&E. Then, it evaluated histologic type and grade according to the methods of Goldschmidt et al. and Peña, respectively. We established real-time PCR quantification assays to measure the mRNA abundances of TLRs in normal and neoplastic mammary glands. Profile pattern of TLR 1, 2, 3, 4, 5, 6, and 9 genes expression in canine mammary glands performed in 21 samples of mammary gland neoplasms and three non-neoplastic mammary gland samples from normal dogs. TLR 3, 4, and 9 mRNA overexpression were detected. In addition, tubulopapillary carcinoma grade II, SCC grade III, and carcinoma mixed type grade II demonstrated the highest relative TLR-3, and 9 mRNA expression levels. Complex carcinoma grade I, ductal carcinoma grade II, and anaplastic carcinoma grade II showed the highest relative TLR4 mRNA expression level. Although histopathological characteristics of tumors, including histologic type, grade, and inflammation, influenced TLRs mRNA expression level, such correlation was insignificant (P > 0.05).

TLR9 and Glioma: Friends or Foes?

Toll-like receptor 9 (TLR9) is an intracellular innate immunity receptor that plays a vital role in chronic inflammation and in recognizing pathogenic and self-DNA in immune complexes. This activation of intracellular signaling leads to the transcription of either immune-related or malignancy genes through specific transcription factors. Thus, it has been hypothesized that TLR9 may cause glioma. This article reviews the roles of TLR9 in the pathogenesis of glioma and its related signaling molecules in either defending or promoting glioma. TLR9 mediates the invasion-induced hypoxia of brain cancer cells by the activation of matrix metalloproteinases (2, 9, and 13) in brain tissues. In contrast, the combination of the TLR9 agonist CpG ODN to radiotherapy boosts the role of T cells in antitumor effects. The TLR9 agonist CpG ODN 107 also enhances the radiosensitivity of human glioma U87 cells by blocking tumor angiogenesis. CpG enhances apoptosis in vitro and in vivo. Furthermore, it can enhance the antigen-presenting capacity of microglia, switch immune response toward CD8 T cells, and reduce the number of CD4CD25 Treg cells. CpG ODN shows promise as a potent immunotherapeutic drug against cancer, but specific cautions should be taken when activating TLR9, especially in the case of glioblastoma.

Targeting Proinflammatory Molecules Using Multifunctional MnO Nanoparticles to Inhibit Breast Cancer Recurrence and Metastasis

Photothermal therapy (PTT) is an effective treatment modality that is highly selective for tumor suppression and is a hopeful alternative to traditional cancer therapy. However, PTT-induced inflammatory responses may result in undesirable side effects including increased risks of tumor recurrence and metastasis. Here we developed multifunctional MnO nanoparticles as scavengers of proinflammatory molecules to alleviate the PTT-induced inflammatory response. The MnO nanoparticles improve the PTT therapy by (1) binding and scavenging proinflammatory molecules to inhibit the proinflammatory molecule-induced Toll-like receptors (TLR) activation and nuclear factor kappa B (NF-κB) signaling; (2) inhibiting activated macrophage-induced macrophage recruitment; and (3) inhibiting tumor cell migration and invasion. In vivo experimental results showed that further treatment with MnO nanoparticles after laser therapy not only inhibited the PTT-induced inflammatory response and primary tumor recurrence but also significantly reduced tumor metastasis due to the scavenging activity. These findings suggest that MnO nanoparticles hold the potential for mitigating the therapy-induced severe inflammatory response and inhibiting tumor recurrence and metastasis.

The relationship between the efficacy of talazoparib and the functional toll-like receptors 3 and 9 in triple negative breast cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) induce cell death by inhibiting the repair of DNA strand breaks binding to PARP and regulate immune cells functions. Toll-like receptors (TLRs) mediate the tumor microenvironment through the modulation of proinflammatory cytokines and chemokines. In this context, this study addressed the relationship between the efficacy of talazoparib (TAL) as a PARPi and the activation of TLR3 or TLR9 by Polyinosinic:polycytidylic acid (Poly I:C) or CpG oligodeoxynucleotides (CpG-ODN) stimulation, respectively in triple negative breast cancer (TNBC). TAL alone and the combination of TAL with Poly I:C or CpG-ODN induced cell death were analyzed by water-soluble tetrazolium salt 1 (WST-1), Annexin V analysis, acridine orange staining and mRNA levels of caspase-3 and caspase-8 in HCC1937 and HCC1937-R (TAL resistant) TNBC cells. Additionally, the expression of TLR3, TLR9 and interferon regulatory factor 7 (IRF7) was observed with immunofluorescence staining and western blot analysis. Our findings showed that TAL induced TLR3 and TLR9 activation and acted in synergy with TLR3 and TLR9 agonists in TNBC cells. The stimulation of TLR3 or TLR9 and TAL treatment caused significantly more apoptosis in TNBC cells through the over-expression of caspase-3 and caspase-8. Additionally, TAL combined with Poly I:C or CpG-ODN more increased TLR3, TLR9 and IRF7 protein levels in HCC1937 cells and treatment with TAL and Poly I:C had greater potential for overcoming TAL resistance. In conclusion, the combination of PARPi with TLR agonists may be a new therapeutic combined strategy for the effective immunotherapy of TNBC.

Breast cancer-derived DAMPs enhance cell invasion and metastasis, while nucleic acid scavengers mitigate these effects

Breast cancer (BC) is the most common malignancy in women. Particular subtypes with aggressive behavior are major contributors to poor outcomes. Triple-negative breast cancer (TNBC) is difficult to treat, pro-inflammatory, and highly metastatic. We demonstrate that TNBC cells express TLR9 and are responsive to TLR9 ligands, and treatment of TNBC cells with chemotherapy increases the release of nucleic-acid-containing damage-associated molecular patterns (NA DAMPs) in cell culture. Such culture-derived and breast cancer patient-derived NA DAMPs increase TLR9 activation and TNBC cell invasion in vitro. Notably, treatment with the polyamidoamine dendrimer generation 3.0 (PAMAM-G3) behaved as a nucleic acid scavenger (NAS) and significantly mitigates such effects. In mice that develop spontaneous BC induced by polyoma middle T oncoprotein (MMTV-PyMT), treatment with PAMAM-G3 significantly reduces lung metastasis. Thus, NAS treatment mitigates cancer-induced inflammation and metastasis and represents a novel therapeutic approach for combating breast cancer.

Toll-like receptors and toll-like receptor-targeted immunotherapy against glioma

Glioma represents a fast proliferating and highly invasive brain tumor which is resistant to current therapies and invariably recurs. Despite some advancements in anti-glioma therapies, patients’ prognosis remains poor. Toll-like receptors (TLRs) act as the first line of defense in the immune system being the detectors of those associated with bacteria, viruses, and danger signals. In the glioma microenvironment, TLRs are expressed on both immune and tumor cells, playing dual roles eliciting antitumoral (innate and adaptive immunity) and protumoral (cell proliferation, migration, invasion, and glioma stem cell maintenance) responses. Up to date, several TLR-targeting therapies have been developed aiming at glioma bulk and stem cells, infiltrating immune cells, the immune checkpoint axis, among others. While some TLR agonists exhibited survival benefit in clinical trials, it attracts more attention when they are involved in combinatorial treatment with radiation, chemotherapy, immune vaccination, and immune checkpoint inhibition in glioma treatment. TLR agonists can be used as immune modulators to enhance the efficacy of other treatment, to avoid dose accumulation, and what brings more interests is that they can potentiate immune checkpoint delayed resistance to PD-1/PD-L1 blockade by upregulating PD-1/PD-L1 overexpression, thus unleash powerful antitumor responses when combined with immune checkpoint inhibitors. Herein, we focus on recent developments and clinical trials exploring TLR-based treatment to provide a picture of the relationship between TLR and glioma and their implications for immunotherapy.

LPS/TLR4 pathways in breast cancer: insights into cell signalling

BACKGROUND

Cancer cells are usually recognized as foreign particles by the immune cells. Mounting evidences suggest important link between toll like receptors (TLRs) and carcinogenesis. This review article focused on the role of TLRs, especially TLR4 in breast cancer. <p> Methods: Research data on TLRs and cancer was explored in PubMed, Scopus, Google Scholar, and reviewed. Although some pioneer works are referenced, papers published in last ten years were mostly cited. <p> Results: TLRs are widely investigated pattern recognition receptors (PRR), and TLR4 is the most studied TLRs, implicated with occurrence of several types of cancers including breast cancer. TLR4 activation occurs via the binding of its ligand lipopolysaccharide (LPS), a component of the outer membrane of gram negative bacteria. Upon LPS binding, TLR4 dimerizes and recruits downstream signalling and/or adapter molecules leading to gene expression related to cancer cell proliferation, survival, invasion, and metastasis. Although LPS/TLR4 signalling seems a single signal transduction pathway, the TLR4 activation results in the activation of multiple diverse intracellular networks with huge cellular responses in both immune and cancer cells. The role of TLR4 in growth, invasion and metastasis of breast cancer is attracting huge attention in oncology research. Several clinical and preclinical studies utilize both TLR4 agonists and antagonists as treatment option for cancer therapy either as monotherapy or adjuvants for vaccine development. <p> Conclusion: This review narrates the role of LPS/TLR4 signalling in breast cancer development and future prospective for targeting LPS/TLR4 axis in the treatment of breast cancer.

Pattern recognition receptors in health and diseases

Pattern recognition receptors (PRRs) are a class of receptors that can directly recognize the specific molecular structures on the surface of pathogens, apoptotic host cells, and damaged senescent cells. PRRs bridge nonspecific immunity and specific immunity. Through the recognition and binding of ligands, PRRs can produce nonspecific anti-infection, antitumor, and other immunoprotective effects. Most PRRs in the innate immune system of vertebrates can be classified into the following five types based on protein domain homology: Toll-like receptors (TLRs), nucleotide oligomerization domain (NOD)-like receptors (NLRs), retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), C-type lectin receptors (CLRs), and absent in melanoma-2 (AIM2)-like receptors (ALRs). PRRs are basically composed of ligand recognition domains, intermediate domains, and effector domains. PRRs recognize and bind their respective ligands and recruit adaptor molecules with the same structure through their effector domains, initiating downstream signaling pathways to exert effects. In recent years, the increased researches on the recognition and binding of PRRs and their ligands have greatly promoted the understanding of different PRRs signaling pathways and provided ideas for the treatment of immune-related diseases and even tumors. This review describes in detail the history, the structural characteristics, ligand recognition mechanism, the signaling pathway, the related disease, new drugs in clinical trials and clinical therapy of different types of PRRs, and discusses the significance of the research on pattern recognition mechanism for the treatment of PRR-related diseases.

Toll-Like Receptor 9-Mediated Neuronal Innate Immune Reaction Is Associated with Initiating a Pro-Regenerative State in Neurons of the Dorsal Root Ganglia Non-Associated with Sciatic Nerve Lesion

One of the changes brought about by Wallerian degeneration distal to nerve injury is disintegration of axonal mitochondria and consequent leakage of mitochondrial DNA (mtDNA)—the natural ligand for the toll-like receptor 9 (TLR9). RT-PCR and immunohistochemical or Western blot analyses were used to detect TLR9 mRNA and protein respectively in the lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) ipsilateral and contralateral to a sterile unilateral sciatic nerve compression or transection. The unilateral sciatic nerve lesions led to bilateral increases in levels of both TLR9 mRNA and protein not only in the lumbar but also in the remote cervical DRG compared with naive or sham-operated controls. This upregulation of TLR9 was linked to activation of the Nuclear Factor kappa B (NFκB) and nuclear translocation of the Signal Transducer and Activator of Transcription 3 (STAT3), implying innate neuronal immune reaction and a pro-regenerative state in uninjured primary sensory neurons of the cervical DRG. The relationship of TLR9 to the induction of a pro-regenerative state in the cervical DRG neurons was confirmed by the shorter lengths of regenerated axons distal to ulnar nerve crush following a previous sciatic nerve lesion and intrathecal chloroquine injection compared with control rats. The results suggest that a systemic innate immune reaction not only triggers the regenerative state of axotomized DRG neurons but also induces a pro-regenerative state further along the neural axis after unilateral nerve injury.

The Preliminary Study for Postoperative Radiotherapy Survival Associated with RUNX3 and TLR9 Expression in Lung Cancer

Background

Many studies have reported that the inflammatory immune response related to TLR9 signaling activation participates in tumor development and affects the treatment outcome. RUNX3 functions as a tumor suppressor by regulating DNA methylation. RUNX3 protein plays an important role in TGF-β signaling pathway that is involved in tumor growth inhibition and apoptosis. At present, radiotherapy is still an important treatment in lung cancer, which induces immune response and affects the therapeutic outcome. The role of TLR9 signaling activation and RUNX3 in this process is not clear.

Methods

In this study, we investigated the expression of TLR9 in tumor and RUNX3 in surrounding tissues by immunohistochemical methods and analyzed the relationship on postoperative survival in lung cancer.

Results

We found that the high expression of TLR9 was the risk factor in postoperative survival of lung cancer with no difference in lifetime. The high expression of RUNX3 in lung cancer with TLR9 signaling activation was in favor of progression-free survival and overall survival in postoperative radiotherapy. It suggested that RUNX3 played an important role in lung cancer radiotherapy. In order to determine the effect of RUNX3 in lung cancer radiation with TLR9 signaling activation, we introduced 5-Aza-2ʹ-deoxycytidine (5-Aza-CdR) and exposed lung cancer A459 cells repeatedly. The high expression of RUNX3 especially RUNX3-B in cells treated with 5-Aza-CdR was observed. We examined that 5-Aza-CdR induced more cell blocking in G2/M phase in combining irradiation.

Conclusion

The result implied that it was feasible to improve radiosensitivity of lung cancer with TLR9 signaling activation by increasing RUNX3 expression, and 5-Aza-CdR was an option in this process.

IFN-I Mediates Lupus Nephritis From the Beginning to Renal Fibrosis

Lupus nephritis (LN) is a common complication of systemic lupus erythematosus (SLE) and a major risk factor for morbidity and mortality. The abundant cell-free nucleic (DNA/RNA) in SLE patients, especially dsDNA, is a key substance in the pathogenesis of SLE and LN. The deposition of DNA/RNA-immune complexes (DNA/RNA-ICs) in the glomerulus causes a series of inflammatory reactions that lead to resident renal cell disturbance and eventually renal fibrosis. Cell-free DNA/RNA is the most effective inducer of type I interferons (IFN-I). Resident renal cells (rather than infiltrating immune cells) are the main source of IFN-I in the kidney. IFN-I in turn damages resident renal cells. Not only are resident renal cells victims, but also participants in this immunity war. However, the mechanism for generation of IFN-I in resident renal cells and the pathological mechanism of IFN-I promoting renal fibrosis have not been fully elucidated. This paper reviews the latest epidemiology of LN and its development process, discusses the mechanism for generation of IFN-I in resident renal cells and the role of IFN-I in the pathogenesis of LN, and may open a new perspective for the treatment of LN.

Tackling Immune Targets for Breast Cancer: Beyond PD-1/PD-L1 Axis

The burden of breast cancer is imposing a huge global problem. Drug discovery research and novel approaches to treat breast cancer have been carried out extensively over the last decades. Although immune checkpoint inhibitors are showing promising preclinical and clinical results in treating breast cancer, they are facing multiple limitations. From an immunological perspective, a recent report highlighted breast cancer as an "inflamed tumor" with an immunosuppressive microenvironment. Consequently, researchers have been focusing on identifying novel immunological targets that can tune up the tumor immune microenvironment. In this context, several novel non-classical immune targets have been targeted to determine their ability to uncouple immunoregulatory pathways at play in the tumor microenvironment. This article will highlight strategies designed to increase the immunogenicity of the breast tumor microenvironment. It also addresses the latest studies on targets which can enhance immune responses to breast cancer and discusses examples of preclinical and clinical trial landscapes that utilize these targets.

Toll-like receptors (TLRs): An old family of immune receptors with a new face in cancer pathogenesis

In the dark path of tumorigenesis, the more carefully the cancer biology is studied, the more brilliant answers could be given to the countless questions about its orchestrating derivers. The identification of the correlation between Toll-like receptors (TLRs) and different processes involved in carcinogenesis was one of the single points of blinding light highlighting the interconnection between the immune system and cancer. TLRs are a wide family of single-pass membrane-spanning receptors that have developed through the evolution to recognize the structurally conserved molecules derived from microorganisms or damaged cells. But this is not everything about these receptors as they could orchestrate several downstream signalling pathways leading to the formation or suppression of cancer cells. The present review is tempted to provide a concise schematic about the biology and the characters of TLRs and also summarize the major findings of the regulatory role of TLRs and their associated signalling in the pathogenesis of human cancers.

Controlling cancer-induced inflammation with a nucleic acid scavenger prevents lung metastasis in murine models of breast cancer

Tumor cells release nucleic acid-containing proinflammatory complexes, termed nucleic acid-containing damage-associated molecular patterns (NA DAMPs), passively upon death and actively during stress. NA DAMPs activate pattern recognition receptors on cells in the tumor microenvironment leading to prolonged and intensified inflammation that potentiates metastasis. No strategy exists to control endogenous or therapy-induced inflammation in cancer patients. We discovered that the generation 3.0 polyamidoamine dendrimer (PAMAM-G3) scavenges NA DAMPs and mitigates their proinflammatory effects. In this study, we tested if the nucleic acid scavenger (NAS) PAMAM-G3 reduces lung metastasis in murine models of breast cancer. Our data indicate that PAMAM-G3 treatment decreases cell-free DNA levels and reduces lung metastasis in the experimental intravenous tumor-injection model and the postsurgical tumor-resection model of 4T1 breast cancer. Reduction in lung metastasis is associated with reduction in inflammatory immune cell subsets and proinflammatory cytokine levels in the tumor and the periphery. This study is the first example of NAS-mediated inhibition of metastasis to the lung. The study results provide a strong rationale for inclusion of NAS therapy in women with breast cancer undergoing standard-of-care surgery.

Interactions between tumor-derived proteins and Toll-like receptors

Damage-associated molecular patterns (DAMPs) are danger signals (or alarmins) alerting immune cells through pattern recognition receptors (PRRs) to begin defense activity. Moreover, DAMPs are host biomolecules that can initiate a noninflammatory response to infection, and pathogen-associated molecular pattern (PAMPs) perpetuate the inflammatory response to infection. Many DAMPs are proteins that have defined intracellular functions and are released from dying cells after tissue injury or chemo-/radiotherapy. In the tumor microenvironment, DAMPs can be ligands for Toll-like receptors (TLRs) expressed on immune cells and induce cytokine production and T-cell activation. Moreover, DAMPs released from tumor cells can directly activate tumor-expressed TLRs that induce chemoresistance, migration, invasion, and metastasis. Furthermore, DAMP-induced chronic inflammation in the tumor microenvironment causes an increase in immunosuppressive populations, such as M2 macrophages, myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs). Therefore, regulation of DAMP proteins can reduce excessive inflammation to create an immunogenic tumor microenvironment. Here, we review tumor-derived DAMP proteins as ligands of TLRs and discuss their association with immune cells, tumors, and the composition of the tumor microenvironment.

Tumor cells killed by radiotherapy or chemotherapy release signaling molecules that stimulate both immune response and tumor aggressiveness; regulating these molecules could improve treatment efficacy. Tae Heung Kang, Yeong-Min Park, and co-workers at Konkuk University, Seoul, South Korea, have reviewed the role of damage-associated molecular patterns (DAMPs) in immunity and cancer. These signaling molecules act as danger signals, activating immune cells by binding to specific receptors. However, tumor cells have the same receptors, and DAMPs binding triggers chemoresistance and increases invasiveness. The researchers report that although DAMPs can trigger a helpful immune response, they can also cause chronic inflammation, which in turn promotes an immune suppression response, allowing tumors to escape immune detection. Improving our understanding of the functions of different DAMPs could improve our ability to boost the immune response and decrease tumor aggressiveness.

Toll-like receptor 4 signaling pathway is correlated with pathophysiological characteristics of AML patients and its inhibition using TAK-242 suppresses AML cell proliferation

PURPOSE

Acute myeloid leukemia (AML) is one of the most severe blood cancers. Many studies have revealed that inflammation has an essential role in the progression of hematopoietic malignancies. Since the toll-like receptor 4 (TLR4) pathway, an important pathway involved in inflammation induction, has previously been associated with solid tumors, we hypothesized that it would be correlated with the pathophysiological characteristics of AML patients and could be considered as an anticancer target.

METHOD

We evaluated the mRNA expression of TLR4, MyD88, RelB, and NF-кB using qRT-PCR in bone-marrow samples of 40 AML patients categorized into four groups according to prognosis, cell type, age, and drug response. Next, we explored the expression of these genes in three AML cell lines (NB4, U937, and KG-1) and used TAK-242, a specific inhibitor of TLR4, to investigate whether this inhibition could suppress AML cell proliferation using cell-cycle analysis. The effect of TAK-242 on arsenic trioxide (ATO) cytotoxicity was also assessed.

RESULT

The results of qRT-PCR showed that most genes had higher expression in patients with poor prognosis or drug-resistant statues. They were also overexpressed in patients with less-differentiated cells. Moreover, TAK-242 inhibited cell proliferation of all the cell lines and altered their cell cycle distribution. It could also intensify the cytotoxicity of ATO in combination therapy.

CONCLUSION

In sum, the TLR4 pathway was related to pathophysiological characteristics of AML and its inhibition using TAK-242 could be considered as a promising treatment strategy in the TLR4 expressing AML cells, individually or in combination with ATO.

Hydroxychloroquine in rheumatic autoimmune disorders and beyond

Initially used as antimalarial drugs, hydroxychloroquine (HCQ) and, to a lesser extent, chloroquine (CQ) are currently being used to treat several diseases. Due to its cost‐effectiveness, safety and efficacy, HCQ is especially used in rheumatic autoimmune disorders (RADs), such as systemic lupus erythematosus, primary Sjögren's syndrome and rheumatoid arthritis. Despite this widespread use in the clinic, HCQ molecular modes of action are still not completely understood. By influencing several cellular pathways through different mechanisms, CQ and HCQ inhibit multiple endolysosomal functions, including autophagy, as well as endosomal Toll‐like receptor activation and calcium signalling. These effects alter several aspects of the immune system with the synergistic consequence of reducing pro‐inflammatory cytokine production and release, one of the most marked symptoms of RADs. Here, we review the current knowledge on the molecular modes of action of these drugs and the circumstances under which they trigger side effects. This is of particular importance as the therapeutic use of HCQ is expanding beyond the treatment of malaria and RADs.

Assessment of TLR4 and TLR9 signaling and correlation with human papillomavirus status and histopathologic parameters in oral tongue squamous cell carcinoma

OBJECTIVES

Toll-like receptors (TLRs) may promote or inhibit tumor progression. The aim of this study was to assess the expression of TLR4 and TLR9 and their downstream targets in oral tongue squamous cell carcinoma (OTSCC) in correlation with histopathologic parameters and human papillomavirus (HPV) status.

STUDY DESIGN

OTSCC (fully or superficially invasive and in situ) were studied. Immunohistochemical expression of TLR4, TLR9, nuclear factor-κΒ (NF-κΒ/p65), and interferon-β (IFN-β) was evaluated in tumor and inflammatory cells and in adjacent morphologically normal mucosa. HPV status was also determined.

RESULTS

TLR4 showed increased expression levels in tumor and infiltrating inflammatory cells compared with adjacent mucosa, especially in fully invasive cases; a negative correlation between TLR4 levels in inflammatory cells and tumor grade was observed. TLR9 was upregulated in tumor and infiltrating inflammatory cells compared with the adjacent mucosa; its expression in inflammatory cells was higher in well differentiated tumors. NF-κΒ and IFN-β were elevated in cancerous tissues, especially in fully invasive cases, and positively correlated with TLR4 and/or TLR9. HPV positivity (detected in 15.9% of the cases) demonstrated positive correlation with TLR9 and NF-κΒ levels.

CONCLUSIONS

TLR4 and TLR9 are upregulated in OTSCC and its microenvironment and, by affecting important downstream molecules, such as NF-κB and IFN-β, may play a role in oral cancer development and progression.

The Potential of Telomeric G-quadruplexes Containing Modified Oligoguanosine Overhangs in Activation of Bacterial Phagocytosis and Leukotriene Synthesis in Human Neutrophils

Human neutrophils are the first line of defense against bacterial and viral infections. They eliminate pathogens through phagocytosis, which activate the 5-lipoxygenase (5-LOX) pathway resulting in synthesis of leukotrienes. Using HPLC analysis, flow cytometry, and other biochemical methods, we studied the effect of synthetic oligodeoxyribonucleotides (ODNs) able to fold into G-quadruplex structures on the main functions of neutrophils. Designed ODNs contained four human telomere TTAGGG repeats (G4) including those with phosphorothioate oligoguanosines attached to the end(s) of G-quadruplex core. Just modified analogues of G4 was shown to more actively than parent ODN penetrate into cells, improve phagocytosis of Salmonella typhimurium bacteria, affect 5-LOX activation, the cytosol calcium ion level, and the oxidative status of neutrophils. As evident from CD and UV spectroscopy data, the presence of oligoguanosines flanking G4 sequence leads to dramatic changes in G-quadruplex topology. While G4 folds into a single antiparallel structure, two main folded forms have been identified in solutions of modified ODNs: antiparallel and dominant, more stable parallel. Thus, both the secondary structure of ODNs and their ability to penetrate into the cytoplasm of cells are important for the activation of neutrophil cellular effects. Our results offer new clues for understanding the role of G-quadruplex ligands in regulation of integral cellular processes and for creating the antimicrobial agents of a new generation.

Expression profile of Toll‑like receptors in human breast cancer

Toll‑like receptors (TLRs) are the most widely studied pattern recognition receptors. Mounting evidence suggests an important association between TLRs and the occurrence and development of breast cancer. Thus, targeting these receptors may be a potential strategy for breast cancer treatment. The current study analyzed the data of 1,215 patients with breast cancer obtained from The Cancer Genome Atlas (TCGA) database. It was observed that, in addition to TLR6, TLR7 and TLR8, the expression of the remaining TLRs in breast cancer tissues was lower than that in normal tissues. In addition, TLR3 and TLR9 displayed significantly different expression levels in ER‑/PR‑negative breast cancer compared with the control tissues, while TLR5 expression was significantly reduced in HER2‑enriched breast cancer. Furthermore, TLR10 exhibited lower expression levels in advanced stages of the disease as compared with that observed in earlier stages. Survival analysis revealed that the expression of TLR4 and TLR7 had a significant impact on survival, and higher expression levels suggested worse prognosis. Finally, the expression levels of TLR1, TLR2, TLR4, TLR5, TLR6 and TLR10 were correlated with those of the inflammatory cytokines interleukin‑1β and tumor necrosis factor‑α, while the expression levels of TLR3, TLR7, TLR8 and TLR9 were correlated with those of interferon‑β and C‑X‑C motif chemokine ligand 10. Taken together, the current study results suggest that TLR expression may serve as a biomarker of cancer pathogenesis and progression, and may provide new insights for the treatment of breast cancer through the regulation and targeting of TLRs.

Targeting MMP-14 for dual PET and fluorescence imaging of glioma in preclinical models

PURPOSE

There is a clinical need for agents that target glioma cells for non-invasive and intraoperative imaging to guide therapeutic intervention and improve the prognosis of glioma. Matrix metalloproteinase (MMP)-14 is overexpressed in glioma with negligible expression in normal brain, presenting MMP-14 as an attractive biomarker for imaging glioma. In this study, we designed a peptide probe containing a near-infrared fluorescence (NIRF) dye/quencher pair, a positron emission tomography (PET) radionuclide, and a moiety with high affinity to MMP-14. This novel substrate-binding peptide allows dual modality imaging of glioma only after cleavage by MMP-14 to activate the quenched NIRF signal, enhancing probe specificity and imaging contrast.

METHODS

MMP-14 expression and activity in human glioma tissues and cells were measured in vitro by immunofluorescence and gel zymography. Cleavage of the novel substrate and substrate-binding peptides by glioma cells in vitro and glioma xenograft tumors in vivo was determined by NIRF imaging. Biodistribution of the radiolabeled MMP-14-binding peptide or substrate-binding peptide was determined in mice bearing orthotopic patient-derived xenograft (PDX) glioma tumors by PET imaging.

RESULTS

Glioma cells with MMP-14 activity showed activation and retention of NIRF signal from the cleaved peptides. Resected mouse brains with PDX glioma tumors showed tumor-to-background NIRF ratios of 7.6-11.1 at 4 h after i.v. injection of the peptides. PET/CT images showed localization of activity in orthotopic PDX tumors after i.v. injection of ⁶⁸Ga-binding peptide or ⁶⁴Cu-substrate-binding peptide; uptake of the radiolabeled peptides in tumors was significantly reduced (p < 0.05) by blocking with the non-labeled-binding peptide. PET and NIRF signals correlated linearly in the orthotopic PDX tumors. Immunohistochemistry showed co-localization of MMP-14 expression and NIRF signal in the resected tumors.

CONCLUSIONS

The novel MMP-14 substrate-binding peptide enabled PET/NIRF imaging of glioma models in mice, warranting future image-guided resection studies with the probe in preclinical glioma models.

Modified Genomic Self-DNA Influences In Vitro Survival of HT29 Tumor Cells via TLR9- and Autophagy Signaling

In relation of immunobiology, the consequence of the crosstalk between TLR9-signaling and autophagy is poorly documented in HT29 cancer cells. To assess the TLR9-mediated biologic effects of modified self-DNA sequences on cell kinetics and autophagy response HT29 cells were incubated separately with intact genomic (g), hypermethylated (m), fragmented (f), and hypermethylated/fragmented (m/f) self-DNAs. Cell viability, apoptosis, cell proliferation, colonosphere-formation were determined. Moreover, the relation of TLR9-signaling to autophagy response was assayed by real-time RT-PCR, immunocytochemistry and transmission electron microscopy (TEM). After incubation with g-, m-, and m/f-DNAs cell viability and proliferation decreased, while apoptosis increased. F-DNA treatment resulted in an increase of cell survival. Methylation of self-DNA resulted in decrease of TLR9 expression, while it did not influence the positive effect of DNA fragmentation on MyD88 and TRAF6 overexpression, and TNFα downregulation. Fragmentation of DNA abrogated the positive effect of methylation on IRAK2, NFκB and IL-8 mRNA upregulations. In case of the autophagy genes and proteins, g- and f-DNAs caused significant upregulation of Beclin1, Atg16L1, and LC3B. According to TEM analyses, autophagy was present in each group of tumor cells, but to a varying degree. Incubation with m-DNA suppressed tumor cell survival by inducing features of apoptotic cell death, and activated mitophagy. F-DNA treatment enhanced cell survival, and activated macroautophagy and lipophagy. Colonospheres were only present after m-DNA incubation. Our data provided evidence for a close existing interplay between TLR9-signaling and the autophagy response with remarkable influences on cell survival in HT29 cells subjected to modified self-DNA treatments.

The Role of MMP8 in Cancer: A Systematic Review

Matrix metalloproteinases (MMPs) have traditionally been considered as tumor promoting enzymes as they degrade extracellular matrix components, thus increasing the invasion of cancer cells. It has become evident, however, that MMPs can also cleave and alter the function of various non-matrix bioactive molecules, leading to both tumor promoting and suppressive effects. We applied systematic review guidelines to study MMP8 in cancer including the use of MMP8 as a prognostic factor or as a target/anti-target in cancer treatment, and its molecular mechanisms. A total of 171 articles met the inclusion criteria. The collective evidence reveals that in breast, skin and oral tongue cancer, MMP8 inhibits cancer cell invasion and proliferation, and protects patients from metastasis via cleavage of non-structural substrates. Conversely, in liver and gastric cancers, high levels of MMP8 worsen the prognosis. Expression and genetic alterations of MMP8 can be used as a prognostic factor by examination of the tumor and serum/plasma. We conclude, that MMP8 has differing effects on cancers depending on their tissue of origin. The use of MMP8 as a prognostic factor alone, or with other factors, seems to have potential. The molecular mechanisms of MMP8 in cancer further emphasize its role as an important regulator of bioactive molecules.

TLR9-1486C/T polymorphism is associated with hepatocellular carcinoma recurrence after liver transplantation

Aim: To determine whether TLR9 polymorphisms are associated with tumor recurrence after liver transplantation for hepatocellular carcinoma (HCC). Patients & methods: All patients who underwent liver transplantation, and had viable HCC in the explanted liver were included. TLR9-1237C/T and -1486C/T polymorphisms were analyzed by real-time PCR and melting curves analysis. Results: 20 of 159 patients (12.6%) developed post-transplant HCC recurrence. Tumors exceeding Milan criteria, moderately-to-poorly differentiated tumors and microvascular invasion on explants, and pretransplant α-fetoprotein level (all p < 0.01) were associated with an increased risk, while TLR9-1486TT genotype was associated with a decreased risk of HCC recurrence (p = 0.03). Conclusion: TLR9-1486C/T might help to preoperatively identify patients at low risk of post-transplant HCC recurrence.

Glomerular expression of matrix metalloproteinases in systemic lupus erythematosus in association with activity index and renal function

Purpose: The aim of this study was to examine the expression of matrix metalloproteinases (MMPs) MMP-1, MMP-2, MMP-3, MMP-9, and their specific tissue inhibitor TIMP-1 in kidney biopsies of patients with lupus nephritis (LN) and to investigate the relationship between MMPs, activity index, and renal function at the time of kidney biopsy.

Methods: We performed immunohistochemistry with monoclonal antibodies against MMP-1, MMP-2, MMP-3, MMP-9, and TIMP-1 in 58 kidney-biopsy specimens with LN (according to the 2004 ISN/RPS classification) and eight specimens from normal kidney tissue. We used clinical data of 36 patients at the time of kidney biopsy to evaluate the association between MMPs expression and renal function.

Results: We found increased MMP-1, MMP-2, and MMP-3 expression in LN glomeruli and a significant correlation with the activity features, with higher activity index score and worse renal function (p < .001). In particular, we have noticed a significant correlation of MMP-1 with leukocyte influx (OR:16.5 95%CI 4.3–62.5 p < .001), and MMP-3 with glomerular hypercellularity (OR:18.6 95%CI 4.8–72.8 p < .001). Moreover, we found a strong correlation of MMP-2 expression with fibrinoid necrosis and cellular crescents formation (OR:17.1 95%CI 4.3–67.7 p < .001).

Conclusions: MMP expression in renal biopsy of patients with LN is increased and directly related to a highly active inflammatory response. Moreover, stronger MMP expression is associated with higher activity index and a more profound renal dysfunction.

Toll-Like Receptor 4 and Matrix Metalloproteases 11 and 13 as Predictors of Tumor Recurrence and Survival in Stage II Colorectal Cancer

Current clinical-pathologic stratification factors do not allow clear identification of high-risk stage II colorectal cancer (CRC) patients. Therefore, the identification of additional prognostic markers is desirable. Toll-like receptor (TLR)-4 is activated during tumorigenesis and matrix metalloproteases (MMPs) are involved in invasion and metastasis. We aimed to evaluate the expression and clinical relevance of TLR4, MMP11 and MMP13 for patients with stage II CRC. Immunohistochemistry was used to study the expression of TLR4, MMP11 and MMP13 in 96 patients with stage II CRC. We measured the global expression and the expression by different cell types (tumor cells, cancer-associated fibroblasts (CAFs) and mononuclear inflammatory cells (MICs)). The potential relationship between expressions of factors and different prognostic variables were evaluated. Our results show significant relationships between either TLR4 expression by tumor cells and MMP11 expression by CAFs and high risk of tumor recurrence. In addition, the concurrence of age ≥ 75 years and the non-expression of MMP11 by CAFs identify a subgroup of patients with a good prognosis. Our results show that TLR4 expression by tumor cells and MMP11 expression by CAFs may to improve the identification of patients with stage II CRC with a high-risk of relapse.

Helicobacter pylori DNA promotes cellular proliferation, migration, and invasion of gastric cancer by activating toll-like receptor 9

BACKGROUND/AIM

Helicobacter pylori (H. pylori) infection is a well-known risk factor for gastric cancer. Toll-like receptor 9 (TLR9) plays an important role in many cancers and is important for immunity to H. pylori infection. Thus, the present study aimed to evaluate the influence of H. pylori on TLR9 and explore its roles in gastric cancer.

MATERIALS AND METHODS

TLR9 expression in MKN45 cells, which were cocultured with or without H. pylori or H. pylori DNA, was detected using quantitative reverse transcription-polymerase chain reaction and Western blot assays. Then, TLR9 was knocked down through RNA interference technology in MKN45 cells. Cell Counting Kit-8 assay was performed to investigate cell proliferation, and the Transwell system was established to test the migrative and invasive abilities of MKN45 cells.

RESULTS

H. pylori infection or H. pylori DNA level was positively correlated with TLR9 upregulation in MKN45 cells. In vitro, H. pylori DNA significantly accelerated cell proliferation and promoted the migration and invasion in MKN45 cells. In contrast, the knockdown of TLR9 significantly suppressed cell proliferation and inhibited the migration and invasion in MKN45 cells.

CONCLUSIONS

The present results suggest that the H. pylori DNA/TLR9-signaling pathway plays an important role in gastric cancer, which might be a potential therapeutic target.

Toll like receptor 7 expressed by malignant cells promotes tumor progression and metastasis through the recruitment of myeloid derived suppressor cells

In non-small cell lung carcinoma (NSCLC), stimulation of toll-like receptor 7 (TLR7), a receptor for single stranded RNA, is linked to tumor progression and resistance to anticancer chemotherapy. However, the mechanism of this effect has been elusive. Here, using a murine model of lung adenocarcinoma, we demonstrate a key role for TLR7 expressed by malignant (rather than by stromal and immune) cells, in the recruitment of myeloid derived suppressor cells (MDSCs), induced after TLR7 stimulation, resulting in accelerated tumor growth and metastasis. In adenocarcinoma patients, high TLR7 expression on malignant cells was associated with poor clinical outcome, as well as with a gene expression signature linked to aggressiveness and metastastic dissemination with high abundance of mRNA encoding intercellular adhesion molecule 1 (ICAM-1), cytokeratins 7 and 19 (KRT-7 and 19), syndecan 4 (SDC4), and p53. In addition, lung tumors expressing high levels of TLR7 have a phenotype of epithelial mesenchymal transition with high expression of vimentin and low abundance of E-cadherin. These data reveal a crucial role for cancer cell-intrinsic TLR7 expression in lung adenocarcinoma progression.

Cell-free DNA derived from cancer cells facilitates tumor malignancy through Toll-like receptor 9 signaling-triggered interleukin-8 secretion in colorectal cancer

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.

TLR9 signaling activation at different stages in colorectal cancer and NF-kappaB expression

Background

The relationship of inflammation and tumor is becoming more and more important in the study on the pathogenesis of colorectal cancer. The role of TLR9-mediated immune inflammation reaction in the process is not currently clear. The purpose of the study was to discuss the correlation of TLR9 signal activation with tumor progression by detecting the expression of TLR9 and its downstream molecule NF-kappaB in colorectal cancer tissues at different stages.

Methods

TLR9 expression in colorectal cancer tissues was detected by immunohistochemical streptavidin-perosidase method and Western blot.

Results

The result showed that the high expression of TLR9 was correlated with tumor poorly differentiation, invasion and liver metastasis, the abnomal increasing levels of CEA in blood. With the signal activation, the levels of TLR9 protein raised more in advanced colorectal cancer than in early colorectal cancer. Afterward, we found that the activation of specific expression of TLR9 signal was related to histologic origin. TLR9-C expression displayed in both advanced cancer and para-carcinoma tissues, and TLR9-R protein was predominat in partial sigmoid and rectal cancer tissues. With the differential expression of TLR9, the levels of its downstream molecule NF-kappaB protein increased in colon cancer tissues and decreased in rectal cancer tissues.

Conclusion

The results confirmed that TLR9 signaling activation participated in the clinical process of colorectal cancer and influenced NF-kappaB expression.

Cell membrane and intracellular expression of toll-like receptor 9 (TLR9) in colorectal cancer and breast cancer cell-lines

BACKGROUND

Toll-like receptor 9 (TLR9) is a DNA receptor of innate immune system which plays a pivotal role in inflammatory response. Recent evidence reveals over-expression and functionality of TLR9 in a wide variety of cancer cells and its contribution to tumor cell proliferation and survival.

OBJECTIVE

In this study, we assessed the aberrant cell surface expression of TLR9 in cancer using cell-lines model.

METHODS

Three breast cancer cell-lines (MDA-MB-231, MCF7 and SKBR3) and five colorectal adenocarcinoma cell-lines (HT29, HT29/219, SW480, SW48 and SW1116) in addition to one primary foreskin isolated fibroblast cell were analyzed for cell surface and intracellular expression of TLR9 by flow cytometry method.

RESULTS

Maximum surface expression of TLR9 was observed in colorectal cell-line HT29/219 (38.35%), as compared with the bottom line fibroblast normal cells (0.12%). The most intracellular expression was observed in MCF-7 cells (35.63%), whereas MDA-MB-231 expressed the maximum surface/intra cellular expression (277 times).

CONCLUSIONS

Based on the results, we hypothesize that aberrant surface expression of TLR9 on tumor cells may promote tumor growth and invasion. It might also highlight a dual contradictory role for CpG-ODNs, as adjutant in cancer therapy.

Polymer-Mediated Inhibition of Pro-invasive Nucleic Acid DAMPs and Microvesicles Limits Pancreatic Cancer Metastasis

Nucleic acid binding polymers (NABPs) have been extensively used as vehicles for DNA and RNA delivery. More recently, we discovered that a subset of these NABPs can also serve as anti-inflammatory agents by capturing pro-inflammatory extracellular nucleic acids and associated protein complexes that promote activation of toll-like receptors (TLRs) in diseases such as lupus erythematosus. Nucleic-acid-mediated TLR signaling also facilitates tumor progression and metastasis in several cancers, including pancreatic cancer (PC). In addition, extracellular DNA and RNA circulate on or within lipid microvesicles, such as microparticles or exosomes, which also promote metastasis by inducing pro-tumorigenic signaling in cancer cells and pre-conditioning secondary sites for metastatic establishment. Here, we explore the use of an NABP, the 3^rd generation polyamidoamine dendrimer (PAMAM-G3), as an anti-metastatic agent. We show that PAMAM-G3 not only inhibits nucleic-acid-mediated activation of TLRs and invasion of PC tumor cells in vitro, but can also directly bind extracellular microvesicles to neutralize their pro-invasive effects as well. Moreover, we demonstrate that PAMAM-G3 dramatically reduces liver metastases in a syngeneic murine model of PC. Our findings identify a promising therapeutic application of NABPs for combating metastatic disease in PC and potentially other malignancies.

Basic understanding and therapeutic approaches to target toll-like receptors in cancerous microenvironment and metastasis

Toll-like receptors (TLRs) are transmembrane components that sense danger signals, like damage- and pathogen-associated molecular pattern molecules, as receptors, and maintain homeostasis in tissues. They are mainly involved in immune system activation through a variety of mediators, which either carry out (1) elimination of pathogenic threats and redressing homeostatic imbalances or (2) contribution to the initiation and worsening of pathological conditions, including cancers. Under physiological conditions, TLRs coordinate the innate and adaptive immunity, and inhibit autoimmune disorders. In pathological conditions, such as cancer, they can present both tumor and receptor-specific roles. Although the roles of individual TLRs in various cancers have been described, the effects of targeting TLRs to treat cancer and prevent metastasis are still controversial. A growing body of literature has suggested contribution of both activators and inhibitors of TLR signaling pathway for cancer treatment, dependent on several context-specific factors. In short, TLRs can play dual roles with contradictory outcomes in neoplastic conditions. This hampers the development of TLR-based therapeutic interventions. A better understanding of the interwoven TLR pathways in cancerous microenvironment is necessary to design TLR-based therapies. In this review, we consider the molecular mechanisms of TLRs signaling and their involvement in tumor progression. Therapeutic modalities targeting TLRs for cancer treatment are discussed as well.

Radiosensitization by CpG ODN7909 in an epidermoid laryngeal carcinoma Hep-2 cell line

Objective

To evaluate the radiosensitivity effect of CpG oligodeoxyribonucleotide (ODN) 7909 on human epidermoid cancer strain-2 (Hep-2) cells in vitro and discuss the potential for improved radiotherapy treatment in patients with laryngeal squamous cell carcinoma.

Methods

Toll-like receptor (TLR) 9 expression was assessed in Hep-2 cells using Western blots and reverse transcription polymerase chain reaction. Cell Counting Kit-8 was used to detect Hep-2 cell viability at 24 and 48 h following treatment with different CpG ODN7909 concentrations. Cellular colonization was evaluated using microscopy. Cell cycle distribution and apoptosis rate was determined with flow cytometry. Interleukin (IL)-12 and tumour necrosis factor (TNF)-α concentrations were detected by enzyme-linked immunosorbent assay.

Results

Hep-2 cells were found to express TLR9, and CpG ODN7909 treatment suppressed Hep-2 cell viability in a dose- and time-dependent manner. Cell survival curve analyses revealed a sensitivity enhancement ratio of the mean death dose of 1.225 for CpG ODN7909 plus irradiation versus irradiation alone. Furthermore, the population of Gap 2/mitotic-phase cells, apoptosis rate and secreted IL-12 and TNF-α levels were significantly increased in Hep-2 cells treated with CpG ODN7909 plus irradiation versus IR alone.

Conclusion

CpG ODN7909 enhanced the radiosensitivity of Hep-2 cells in vitro.

Lower frequency of TLR9 variant associated with protection from breast cancer among African Americans

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.

TLR5/7-mediated PI3K activation triggers epithelial-mesenchymal transition of ovarian cancer cells through WAVE3-dependent mesothelin or OCT4/SOX2 expression

Toll-like receptor (TLR)-mediated signaling induces cell migration or invasion in several tumors and various stages of cancer. Interactions of mesothelin, a 40-kDa cell surface glycoprotein, with cancer antigen 125 (CA125) is associated with drug resistance, metastasis, and poor clinical outcome of ovarian cancer patients. In this study, we examined the role of TLR5 and TLR7 in the metastasis of ovarian cancer through the induction of mesothelin/CA125 expression and investigated its underlying mechanism. TLR5 agonist (flagellin) and TLR7 agonist (imiquimod) upregulated mesenchymal phenotypes and produced epithelial-mesenchymal transition (EMT)-related cytokines in the SKOV3 cells; however, TLR7 expressing CaOV3 cells had no response to the specific ligand, imiquimod, for enhancing its EMT processes. Stimulation of the SKOV3 cells with flagellin or imiquimod activated Wiskott-Aldrich syndrome protein verprolin-homologous 3 (WAVE3) and mesothelin/CA125, whereas it suppressed the expression of TAp63. Moreover, knockdown of TLR5 or TLR7 in SKOV3 cells profoundly impaired the TLR5- or TLR7-intiated downstream signaling pathway. Loss of WAVE3 in SKOV3 cells led to the inhibition of invasion, suppression of mesenchymal characteristics, prevention of OCT4/SOX2 secretion, and attenuation of mesothelin/CA125 expression after stimulation with flagellin or imiquimod. Although the disruption of mesothelin decreased the migratory activity of the TLR5/7-activated SKOV3 cells, knockdown of mesothelin failed to reduce the expression of mesenchymal markers, OCT4, and SOX2. In addition, targeting OCT4 or SOX2 with siRNA had no effect on the expression of mesothelin and the suppression of transcriptionally active p63 (TAp63) in the TLR5/7-stimulated SKOV3 cells. Our results suggest that TLR5/7-mediated WAVE3 activation not only controls the mesothelin-related EMT processes but also modulates OCT4/SOX2-mediated mesenchymal marker expression. Taken together, both TLR5 and TLR7 expression are critical for the TLR5/7-induced metastasis of ovarian cancer and the inhibition of WAVE3 might be a new therapeutic target to control ovarian cancer metastasis.

Clients and Oncogenic Roles of Molecular Chaperone gp96/grp94

As an endoplasmic reticulum heat shock protein (HSP) 90 paralogue, glycoprotein (gp) 96 possesses immunological properties by chaperoning antigenic peptides for activation of T cells. Genetic studies in the last decade have unveiled that gp96 is also an essential master chaperone for multiple receptors and secreting proteins including Toll-like receptors (TLRs), integrins, the Wnt coreceptor, Low Density Lipoprotein Receptor-Related Protein 6 (LRP6), the latent TGFβ docking receptor, Glycoprotein A Repetitions Predominant (GARP), Glycoprotein (GP) Ib and insulin-like growth factors (IGF). Clinically, elevated expression of gp96 in a variety of cancers correlates with the advanced stage and poor survival of cancer patients. Recent preclinical studies have also uncovered that gp96 expression is closely linked to cancer progression in multiple myeloma, hepatocellular carcinoma, breast cancer and inflammation-associated colon cancer. Thus, gp96 is an attractive therapeutic target for cancer treatment. The chaperone function of gp96 depends on its ATPase domain, which is structurally distinct from other HSP90 members, and thus favors the design of highly selective gp96-targeted inhibitors against cancer. We herein discuss the strategically important oncogenic clients of gp96 and their underlying biology. The roles of cell-intrinsic gp96 in T cell biology are also discussed, in part because it offers another opportunity of cancer therapy by manipulating levels of gp96 in T cells to enhance host immune defense.

Toll-like receptor 9 expression is associated with breast cancer sensitivity to the growth inhibitory effects of bisphosphonates in vitro and in vivo

Bisphosphonates are standard treatments for bone metastases. When given in the adjuvant setting, they reduce breast cancer mortality and recurrence in bone but only among post-menopausal patients. Optimal drug use would require biomarker-based patient selection. Such biomarkers are not yet in clinical use. Based on the similarities in inflammatory responses to bisphosphonates and Toll-like receptor (TLR) agonists, we hypothesized that TLR9 expression may affect bisphosphonate responses in cells. We compared bisphosphonate effects in breast cancer cell lines with low or high TLR9 expression. We discovered that cells with decreased TLR9 expression are significantly more sensitive to the growth-inhibitory effects of bisphosphonates in vitro and in vivo. Furthermore, cancer growth-promoting effects seen with some bisphosphonates in some control shRNA cells were not detected in TLR9 shRNA cells. These differences were not associated with inhibition of Rap1A prenylation or p38 phosphorylation, which are known markers for bisphosphonate activity. However, TLR9 shRNA cells exhibited increased sensitivity to ApppI, a metabolite that accumulates in cells after bisphosphonate treatment. We conclude that decreased TLR9-expression sensitizes breast cancer cells to the growth inhibitory effects of bisphosphonates. Our results suggest that TLR9 should be studied as a potential biomarker for adjuvant bisphosphonate sensitivity among breast cancer patients.