Toll-like receptors and immune regulation: implications for cancer therapy. Oncogene. 2008;27:181-189. [PMID: 18176599 DOI: 10.1038/sj.onc.1210906]

TLR agonists polarize interferon responses in conjunction with dendritic cell vaccination in malignant glioma: a randomized phase II Trial

In this randomized phase II clinical trial, we evaluated the effectiveness of adding the TLR agonists, poly-ICLC or resiquimod, to autologous tumor lysate-pulsed dendritic cell (ATL-DC) vaccination in patients with newly-diagnosed or recurrent WHO Grade III-IV malignant gliomas. The primary endpoints were to assess the most effective combination of vaccine and adjuvant in order to enhance the immune potency, along with safety. The combination of ATL-DC vaccination and TLR agonist was safe and found to enhance systemic immune responses, as indicated by increased interferon gene expression and changes in immune cell activation. Specifically, PD-1 expression increases on CD4+ T-cells, while CD38 and CD39 expression are reduced on CD8+ T cells, alongside an increase in monocytes. Poly-ICLC treatment amplifies the induction of interferon-induced genes in monocytes and T lymphocytes. Patients that exhibit higher interferon response gene expression demonstrate prolonged survival and delayed disease progression. These findings suggest that combining ATL-DC with poly-ICLC can induce a polarized interferon response in circulating monocytes and CD8+ T cells, which may represent an important blood biomarker for immunotherapy in this patient population.Trial Registration: ClinicalTrials.gov Identifier: NCT01204684.

Patient-Centric Quality Standards

To ensure the quality, safety and efficacy of medicinal products, it is necessary to develop and execute appropriate manufacturing process and product control strategies. Traditionally, product control strategies have focused on testing known quality attributes with limits derived from levels administered in preclinical and clinical studies with an associated statistical analysis to account for variability. However, not all quality attributes have impact to the patient and those with the potential to impact safety and efficacy may not be significant when dosed at patient-centric levels. Therefore, achieving patient-centricity is understanding patient relevance, which is defined as the level of impact that a quality attribute could have on safety and efficacy within the potential exposure range. A patient-centric quality standard (PCQS) is therefore a set of patient relevant attributes and their associated acceptance ranges to which a drug product should conform within the expected patient exposure range. This manuscript describes historical perspectives details the way to create and leverage a PCQS in a variety of pharmaceutical product modalities.

Metal-Phenolic Nanocloaks on Cancer Cells Potentiate STING Pathway Activation for Synergistic Cancer Immunotherapy

Due to the presence of natural neoantigens, autologous tumor cells hold great promise as personalized therapeutic vaccines. Yet autologous tumor cell vaccines require multi-step production that frequently leads to the loss of immunoreactive antigens, causing insufficient immune activation and significantly hampering their clinical applications. Herein, we introduce a novel whole-cell cancer vaccine by cloaking cancer cells with lipopolysaccharide-decorated manganese(II)-phenolic networks (MnTA nanocloaks) to evoke tumor-specific immune response for highly efficacious synergistic cancer immunotherapy. The natural polyphenols coordinate with Mn2+ and immediately adhere to the surface of individual cancer cells, thereby forming a nanocloak and encapsulating tumor neoantigens. Subsequent decoration with lipopolysaccharide induces internalization by dendritic cells, where Mn2+ ions are released in the cytosol, further facilitating the activation of the stimulator of the interferon genes (STING) pathway. Highly effective tumor suppression was observed by combining the nanocloaked cancer cell treatment with anti-programmed cell death ligand 1 (anti-PD-L1) antibodies-mediated immune checkpoint blockade therapy. Our work demonstrates a universal yet simple strategy to engineer a cell-based nanobiohybrid system for enhanced cancer immunotherapy.

An Interleukin-17 Isoform from Thick Shell Mussel Mytilus coruscus Serves as a Mediator of Inflammatory Response

The inflammatory cytokine interleukin-17 (IL17) plays an important role in innate immunity by binding to its receptors (IL17Rs) to activate immune defense signals. To date, information on members of the IL17 family is still very limited in molluscan species. Here, a novel member of the IL17 family was identified and characterized from thick shell mussel Mytilus coruscus, and this gene was designated as McIL17-1 by predicting structural domains and phylogenetic analysis. McIL17-1 transcripts existed in all examined tissues with high expression levels in gills, hemocytes and digestive glands. After the stimuli of different pathogen associated molecular patterns (PAMPs) for 72 h, transcriptional expression of McIL17-1 was significantly upregulated, except for poly I:C stimulation. Cytoplasm localization of McIL17-1 was shown in HEK293T cells by fluorescence microscopy. Further, in vivo and in vitro assays were performed to evaluate the potential function of McIL17-1 played in immune response. McIL17-1 was either knocked down or overexpressed in vivo through RNA inference (RNAi) and recombinant protein injection, respectively. With the infection of living Vibrio alginolyticus, a high mortality rate was exhibited in the McIL17-1 overexpressed group compared to the control group, while a lower mortality rate was observed in the McIL17-1 knocked down group than control group. In vitro, the flow cytometric analysis showed that the apoptosis rate of McIL17-1 inhibited hemocytes was significantly lower than that of the control group after lipopolysaccharide stimulation. These results collectively suggested that the newly identified IL17 isoform is involved in the inflammatory response to bacterial infection in M. coruscus.

Fucoidan, as an immunostimulator promotes M1 macrophage differentiation and enhances the chemotherapeutic sensitivity of capecitabine in colon cancer

Chemotherapy resistance is one of the most critical challenges in colorectal cancer (CRC) treatment. The occurrence and development of chemotherapy resistance closely related to the tumor immune microenvironment (TIME). As the most important immunosuppressive immune cells infiltrating into the TIME, macrophages are essential for chemotherapy resistance in CRC treatment. In this study, we found that a kind of fucoidan (FPS1M) induced macrophages differentiation to the M1 phenotype, and this transformation promoted cancer cells apoptosis both in vitro and in vivo. TNFα is a key mediator of FPS1M-induced tumorcidal activity of macrophages. Mechanistically, as a stimulator of TLR4, FPS1M enhanced macrophages glycolysis and regulated macrophages differentiation to the M1 phenotype by the activation of TLR4 mediated PI3K/AKT/mTOR signaling axis. In addition, FPS1M improved the immunosuppressed tumor microenvironment by increasing the infiltration of M1 macrophages in tumor tissue, which was conducive to improving the sensitivity of tumor to chemotherapy. Collectively, our findings demonstrated that FPS1M has the great potential to be used in tumor immunotherapy. The results also suggested that the combination of FPS1M with capecitabine is an alternative therapy method for colon cancer.

Saga of monokines in shaping tumour-immune microenvironment: Origin to execution

Cellular communication mediated by cytokines is an important mechanism dictating immune responses, their cross talk and final immune output. Cytokines play a major role in dictating the immune outcome to cancer by regulating the events of development, differentiation and activation of innate immune cells. Cytokines are pleiotropic in nature, hence understanding their role individually or as member of network cytokines is critical to delineate their role in tumour immunity. Tumour systemically manipulates the immune system to evade and escape immune recognition for their uncontrollable growth and metastasis. The developing tumour comprise a large and diverse set of myeloid cells which are vulnerable to manipulation by the tumour-microenvironment. The innate immune cells of the monocytic lineage skew the fate of the adaptive immune cells and thus dictating cancer elimination or progression. Targeting cells at tumour cite is preposterous owing to their tight network, poor reach and abundance of immunosuppressive mechanisms. Monocytic lineage-derived cytokines (monokines) play crucial role in tumour regression or progression by either directly killing the tumour cells with TNFα or promoting its growth by TGFβ. In addition, the monokines like IL-12, IL-1β, IL-6, IL-10 and TGFβ direct the adaptive immune cells to secrete anti-tumour cytokines, TNFα, IFNγ, perforin and granzyme or pro-tumour cytokines, IL-10 and TGFβ. In this review, we elucidate the roles of monokines in dictating the fate of tumour by regulating responses at various stages of generation, differentiation and activation of immune cells along with the extensive cross talk. We have attempted to delineate the synergy and antagonism of major monokines among themselves or with tumour-derived or adaptive immune cytokines. The review provides an update on the possibilities of placing monokines to potential practical use as cytokine therapy against cancer.

Toll-Like Receptor Signaling and Its Role in Cell-Mediated Immunity

Innate immunity is the first defense system against invading pathogens. Toll-like receptors (TLRs) are well-defined pattern recognition receptors responsible for pathogen recognition and induction of innate immune responses. Since their discovery, TLRs have revolutionized the field of immunology by filling the gap between the initial recognition of pathogens by innate immune cells and the activation of the adaptive immune response. TLRs critically link innate immunity to adaptive immunity by regulating the activation of antigen-presenting cells and key cytokines. Furthermore, recent studies also have shown that TLR signaling can directly regulate the T cell activation, growth, differentiation, development, and function under diverse physiological conditions. This review provides an overview of TLR signaling pathways and their regulators and discusses how TLR signaling, directly and indirectly, regulates cell-mediated immunity. In addition, we also discuss how TLR signaling is critically important in the host's defense against infectious diseases, autoimmune diseases, and cancer.

Toll-Like Receptor Signaling and Its Role in Cell-Mediated Immunity

Innate immunity is the first defense system against invading pathogens. Toll-like receptors (TLRs) are well-defined pattern recognition receptors responsible for pathogen recognition and induction of innate immune responses. Since their discovery, TLRs have revolutionized the field of immunology by filling the gap between the initial recognition of pathogens by innate immune cells and the activation of the adaptive immune response. TLRs critically link innate immunity to adaptive immunity by regulating the activation of antigen-presenting cells and key cytokines. Furthermore, recent studies also have shown that TLR signaling can directly regulate the T cell activation, growth, differentiation, development, and function under diverse physiological conditions. This review provides an overview of TLR signaling pathways and their regulators and discusses how TLR signaling, directly and indirectly, regulates cell-mediated immunity. In addition, we also discuss how TLR signaling is critically important in the host's defense against infectious diseases, autoimmune diseases, and cancer.

Bibliometric analysis of toll-like receptor agonists associated with cancer therapy

BACKGROUND

Toll-like receptors (TLRs), a family of innate pattern-recognition receptors, have been exploited as a target for antitumor strategy. An increasing number of TLR agonists, serving as immunotherapeutics or vaccine adjuvants, were developed. This study aimed at exploring the status and trend of current researches on TLR agonists through bibliometric analysis.

METHODS

Original publications on TLR agonists were collected from the Web of Science Core Collection. Data were analyzed in terms of publication outputs, journals, countries, institutions, authors, co-authorship, co-citation, research hotspots, and evolution trends through VOSviewer and CiteSpace.

RESULTS

A total of 1914 TLR agonists-related articles, published in 612 academic journals between 2000 and 2019, were enrolled in the study. The Journal of Immunology published the most publications, followed by PLoS One and Blood. The USA that is in possession of the largest number of articles and the most extensive cooperators was the most leading country in this field. University of Minnesota ranked the first in terms of paper totality, but its average citations ranking was lower than University of Pennsylvania. Gudkov AV was the most productive author, whose team reported a TLR5 agonist that had radioprotective activity in mouse and primate models in 2008. The paper of Akira Shizuo, professor of Osaka University, was widely cited by international peers. The research trend of TLR agonists has undergone 3 periods: mechanisms of TLR signalings in immunotherapy (2000-2010), discovery of TLR agonists (2011-2014), application, therapeutic evaluation, and drug design of TLR agonists (2015-2019).

CONCLUSION

This study provides investigators a landscape of TLR agonists research from the perspective of bibliometrics.

Pseudomonas aeruginosa PcrV Enhances the Nitric Oxide-Mediated Tumoricidal Activity of Tumor-Associated Macrophages via a TLR4/PI3K/AKT/mTOR-Glycolysis-Nitric Oxide Circuit

Tumor-associated macrophages (TAMs), which display a tumor-supportive M2 phenotype, are closely related to tumor growth and metastasis. The reprogramming of TAMs toward a tumoricidal M1 profile has emerged as an attractive strategy for cancer immunotherapy. In this study, we found that the intratumoral injection of PcrV protein, a component of the Pseudomonas aeruginosa type 3 secretion system, suppressed tumor growth and increased apoptosis, inducible nitric oxide synthase (iNOS) expression, and the percentage of M1-polarized TAMs in tumor tissues. Furthermore, the intratumoral injection of PcrV-primed macrophages exerted a similar tumoricidal effect. In vitro analyses revealed that PcrV reeducated TAMs toward an antitumoral M1 phenotype and augmented their nitric oxide (NO)-mediated cytotoxicity against cancer cells. Mechanistically, we found that these effects were dependent on the activation of Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)-mediated regulation of a PI3K/AKT/mTOR-glycolysis-NO feedback loop via direct interaction with TLR4. Collectively, these results revealed a potential role for PcrV in cancer immunotherapy through the targeting of TAM plasticity.

Effect of Papaya Leaves (<i>Carica papaya</i> L.) Extract on Immune Response (TLR-7, TLR-9) and Inflammation (COX-2) in Rats Induces DMBA (7,12-Dimethylbenz[a]antrasen)

BACKGROUND AND OBJECTIVE

TLR is known to regulate the immune system in cancer. TLR-7 and TLR-9 can enhance the antitumor immune system in many types of solid tumors. Cyclooxygenase-2 (COX-2) is a biomarker of inflammation. This study aimed to investigate the effect of papaya leaves extract on immune response (TLR 7, TLR 9) and inflammation (COX-2) in rats induced DMBA.

MATERIALS AND METHODS

This experimental study used Sprague dawley female rats of age more less 50 days. Rats were divided into 4 groups: Negative Control (NC), Positive Control (PC), Cancer Drug Doxorubicin (DOXO) and Papaya Leaves Extract (PLE). The study was conducted for 13 weeks. DMBA induction performed for 5 weeks with administration of 2 times per week.

RESULTS

the expression of TLR-7 of PLE and DOXO was higher than PC groups significantly different (p<0.05). The expression of TLR-9 of PLE was higher than NC, PC and DOXO groups but not significantly different (p>0.05) while the expression of COX-2 of PLE and DOXO groups was lower than NC and PC groups but not significantly different (p>0.05).

CONCLUSION

It can be concluded that papaya leaves extract can improve the immune system and reduce inflammation. It shows that papaya leaves extract has potent as anti-cancer.

Immunoadjuvants for cancer immunotherapy: A review of recent developments

Cancer immunotherapy evolved as a new treatment modality to eradicate tumor cells and has gained in popularity after its successful clinical transition. By activating antigen-presenting cells (APCs), and thus, inducing innate or adaptive immune responses, immunoadjuvants have become promising tools for cancer immunotherapy. Different types of immunoadjuvants such as toll-like receptor (TLR) agonists, exosomes, and metallic and plant-derived immunoadjuvants have been studied for their immunological effects. However, the clinical use of immunoadjuvants is limited by short response rates and various side-effects. The rapid progress made in the development of nanoparticle systems as immunoadjuvant carrier vehicles has provided potential carriers for cancer immunotherapy. In this review article, we describe different types of immunoadjuvants, their limitations, modes of action, and the reasons for their clinical adoption. In addition, we review recent progress made in the nanoparticle-based immunoadjuvant field and on the combined use of nanoparticle-based immunoadjuvants and chemotherapy, phototherapy, radiation therapy, and immune checkpoint inhibitor-based therapy. STATEMENT OF SIGNIFICANCE: Cancer immunotherapy emerged as a new hope for treating malignant tumors. Different types of immunoadjuvants serve as an important tool for cancer immunotherapy by activating an innate or adaptive immune response. Limitation of free immunoadjuvant has paved the path for the development of nanoparticle-based immunoadjuvant therapy with the hope of prolonging the therapeutic efficacy. This review highlights the recent advancement made in nanoparticle-based immunoadjuvant therapy in modulating the adaptive and innate immune system. The application of the combinatorial approach of chemotherapy, phototherapy, radiation therapy adds synergy in nanoparticle-based immunoadjuvant therapy. It will broaden the reader's understanding on the recent progress made in immunotherapy with the aid of immunoadjuvant-based nanosystem.

Development of a novel TLR8 agonist for cancer immunotherapy

Toll-like receptors (TLRs) are a family of proteins that recognize pathogen associated molecular patterns (PAMPs). Their primary function is to activate innate immune responses while also involved in facilitating adaptive immune responses. Different TLRs exert distinct functions by activating varied immune cascades. Several TLRs are being pursued as cancer drug targets. We discovered a novel, highly potent and selective small molecule TLR8 agonist DN052. DN052 exhibited strong in vitro cellular activity with EC50 at 6.7 nM and was highly selective for TLR8 over other TLRs including TLR4, 7 and 9. DN052 displayed excellent in vitro ADMET and in vivo PK profiles. DN052 potently inhibited tumor growth as a single agent. Moreover, combination of DN052 with the immune checkpoint inhibitor, selected targeted therapeutics or chemotherapeutic drugs further enhanced efficacy of single agents. Mechanistically, treatment with DN052 resulted in strong induction of pro-inflammatory cytokines in ex vivo human PBMC assay and in vivo monkey study. GLP toxicity studies in rats and monkeys demonstrated favorable safety profile. This led to the advancement of DN052 into phase 1 clinical trials.

High Molecular Weight Chitosan-Complexed RNA Nanoadjuvant for Effective Cancer Immunotherapy

Nucleic acid-based adjuvants have recently emerged as promising candidates for use in cancer vaccines to induce tumor-suppressing immune cells. In this study, we tested whether complexation of a nucleic acid-based adjuvant with chitosan (CTS) modulates immune adjuvant functions. As a nucleic acid-based adjuvant, we used toll-like receptor 3-recognizing RNA adjuvant (RA). Negatively charged RA formed nanoscale polyplexes with cationic CTS that possessed positive zeta potentials. RA/CTS polyplexes exerted dendritic cell (DC)-maturation effects without causing significant DC toxicity. This DC-maturation effect was CTS molecular weight dependent, with RA/CTS polyplexes with a CTS molecular weight of 340 kDa (RA/CTS 340K) producing the greatest effect. Subcutaneous injection of RA/CTS 340K polyplexes with the model tumor antigen ovalbumin exerted a preventive effect against challenge by ovalbumin-expressing tumor cells. It also provided greater inhibitory effects against a second challenge with the same tumor cells compared with other treatments. These protective effects of subcutaneous RA/CTS polyplex treatment were associated with the highest tumor antigen-specific humoral and cellular immune responses after tumor challenge, and with the greatest infiltration of CD4 helper T cell and CD8 T cell into the tumor tissues. Mice vaccinated with ovalbumin and RA/CTS polyplexes showed complete survival, even after repeated challenge with tumor cells. Our results suggest the potential of RA/CTS polyplexes as effective nanoadjuvants in the design of tumor vaccines and cancer immunotherapy.

Hypoxia-induced shedding of MICA and HIF1A-mediated immune escape of pancreatic cancer cells from NK cells: role of circ_0000977/miR-153 axis

One key to malignant progression of pancreatic cancer (PC) is the acquired ability of tumour cells to escape immune-mediated lysis. Hypoxic microenvironment plays a causal role in PC metastasis. According to previous studies, hypoxia could induce the upregulation of HIF1A, ADAM10 and sMICA, leading to decreased NKG2D in NK cells and tumour cells escape from immune surveillance and NK cell-mediated lysis. In the present study, in NK cells derived from high-HIF1A expression patients, the levels of internalization of MICA/B and NKG2D were obviously higher than those in low-HIF1A expression group; hypoxia dramatically upregulated the levels of sMICA culture supernatant of Panc-1 cells. Regarding the molecular mechanism, dysregulated circRNAs and miRNAs that might modulate HIF1A-mediated immune escape were selected and examined for detailed functions. The expression of circ_0000977 could be induced by hypoxia, and circ_0000977 knockdown enhanced the killing effect of NK cells on PC cells under hypoxia through HIF1A and ADAM10. HIF1 and ADAM10 were direct downstream targets of miR-153; circ_0000977 served as a sponge for miR-153 to counteract miR-153-mediated repression of HIF1 and ADAM10 mRNA through direct targeting in both 293T cells and Panc-1 cells. miR-153 inhibition exerted an opposing effect on HIF1A-mediated immune escape of PC cells to circ_0000977 knockdown; the effect of circ_0000977 knockdown were partially attenuated by miR-153 inhibition. In summary, circ_0000977/miR-153 axis modulates HIF1A-mediated immune escape of PC cells through miR-153 downstream targets HIF1A and ADAM10. We provided a novel mechanism of HIF1A-mediated immune escape of PC cells from the perspective of circRNAs-miRNA-mRNA axis. Abbreviations: Pancreatic cancer (PC); peripheral blood lymphocytes (PBLs); A Disintegrin and Metalloproteinase Domain 10 (ADAM10); MHC class I-related molecule A (MICA); soluble MICA (sMICA); membrane MICA (mMICA); Hypoxia-inducible factor 1-alpha (HI1FA); long non-coding RNAs (lncRNAs); non-coding RNAs (ncRNAs); natural killer (NK); Haematoxylin and eosin (H&E); Immunohistochemistry (IHC); natural killer group 2 member D (NKG2D).

Co-delivery of immunomodulators in biodegradable nanoparticles improves therapeutic efficacy of cancer vaccines

To improve the efficacy of cancer vaccines we aimed to modulate the suppressive tumor microenvironment. In this study, the potential of intratumoral immune modulation with poly (I:C), Resiquimod (R848) and CCL20 (MIP3α) was explored. Biodegradable polymeric nanoparticles were used as delivery vehicles for slow and sustained release of these drugs in the tumor area and were combined with specific immunotherapy based on therapeutic peptide vaccination in two aggressive murine carcinoma and lymphoma tumor models. Whereas nanoparticle delivery of poly (I:C) or R848 improved therapeutic efficacy, the combination with MIP3α remarkably potentiated the cancer vaccine antitumor effects. The long-term survival increased to 75-100% and the progression free survival nearly doubled on mice with established large carcinoma tumors. The potent adjuvant effects were associated with lymphoid and myeloid population alterations in the tumor and tumor-draining lymph node. In addition to a significant influx of macrophages into the tumor, the phenotype of the suppressor tumor-associated macrophages shifted towards an acute inflammatory phenotype in the tumor-draining lymph node. Overall, these data show that therapeutic cancer vaccines can be potentiated by the combined nanoparticle mediated co-delivery of poly (I:C), R848 and MIP3α, which indicates that a more favorable milieu for cancer fighting immune cells is created for T cells induced by therapeutic cancer vaccines.

Toll-like receptor-targeted particles: A paradigm to manipulate the tumor microenvironment for cancer immunotherapy

The expression of Toll-like receptors (TLRs) on antigen presenting cells, especially dendritic cells, offers several sensitive mediators to trigger an adaptive immune response, which potentially can be exploited to detect and eliminate pathogenic objects. Consequently, numerous agonists that target TLRs are being used clinically either alone or in combination with other therapies to strengthen the immune system in the battle against cancer. This review summarizes the roles of TLRs in tumor biology, and focuses on relevant TLR-dependent antitumor pathways and the conjugation of TLR agonists as adjuvants to nano- and micro-particles for boosting responses leading to cancer suppression and eradication. STATEMENT OF SIGNIFICANCE: Toll-like receptors (TLRs), which express on antigen presenting cells, such as dendritic cells and macrophages, play an important role in sensing pathogenic agents and inducing adaptive immunity. As a result, several TLR agonists have been investigating as therapeutic agents individually or in combination with other treatment modalities for cancer treatment through boosting the immune system. This review aims to focus on the roles of TLRs in cancer and TLR-dependent antitumor pathways as well as the use of different nano- or micro-particles bearing TLR agonists for tumor inhibition and elimination.

Increased risks between TLR2 (-196 to -174 ins/del) and TLR3 1377C>T variants and head and neck cancers in Tunisia

Introduction

Previous studies have highlighted the importance of polymorphisms of toll-like receptors (TLRs) in the pathogenesis of certain cancers, including head and neck cancers (HNC).

Aim of the study

The aim of this study was to evaluate the association of TLR2 (-196 to -174 ins/del) and TLR3 (1377 C>T) as potential risk factors for HNC in Tunisians.

Material and methods

A case-control study including 246 HNC patients (174 nasopharyngeal carcinoma – NPC and 72 laryngeal cancer – LC) and 250 healthy controls. Genotyping was done by using PCR and PCR-RFLP methods.

Results

Higher minor allele frequencies of TLR2 (-196 to -174 ins/del) and TLR3 1377 C>T polymorphisms were seen in HNC, NPC, and LC compared to controls. In addition, higher increased HNC, NPC, and LC risk was associated with TLR2 ins/del and TLR2 del/del genotypes (p < 0.0001). Positive association with HNC, NPC, and LC risk was seen with TLR2 del-containing genotypes (ins/del + del/del) (p < 0.0001). The T/T genotype of TLR3 is associated with HNC, NPC, and LC susceptibility (p < 0.0001). Positive association with HNC and NPC risk was seen with TLR3 T allele carriers (C/T + T/T) (p < 0.0001). Increased frequency of T-ins, C-del, and T-del haplotypes was revealed in HNC and NPC cases than healthy controls; however, T-del was significantly higher in LC cases.

Conclusions

Our results demonstrate an increased risk of HNC, NPC, and LC with TLR2 ins/del, TLR2 del/del, and TLR3 T/T genotypes. And positive association with T-ins, C-del, and T-del haplotypes with HNC and NPC and T-del haplotype with LC.

The immunostimulatory effects and pro-apoptotic activity of rhCNB against Lewis lung cancer is mediated by Toll-like receptor 4

Background

Recombinant human calcineurin B subunit (rhCNB) has been shown to be an immune‐stimulatory protein promoting cytokine production and inducing phenotypic maturation of Dendritic cells (DCs). In vivo, it has good antitumor efficacy, and has potential as an antitumor drug. Exogenous rhCNB was found to be internalized into tumor cells via the Toll‐like receptor 4 (TLR4) complex, but it was not known whether its immuno‐modulatory and antitumor functions involved entry by this same route.

Methods

The production and secretion of the cytokines and chemokines in innate immune cells induced by rhCNB were determined by ELISA, and the expression of CD40, CD80, CD86, and MHCII was analyzed by FACs. Experimental Lewis lung cancer (LLC) model was prepared in C57 BL/6 wild‐type (WT) mice, TLR4^−/− mice or their littermates by the inoculation of LLCs in their right armpit, and then administrated daily intraperitoneal injections (0.2 mL) of normal saline, rhCNB 20 mg/kg, and rhCNB 40 mg/kg, respectively.

Results

Recombinant human calcineurin B subunit promoted the production of antitumor cytokines by innate immune cells, and culture supernatants of rhCNB‐stimulated immune cells induced apoptosis of LLCs. In addition, rhCNB up‐regulated CD40, CD80, CD86, and MHCII expression in macrophages and DCs in TLR4⁺ cells but failed to do so in TLR4 deficient cells. rhCNB also induced the formation of CD4⁺ and CD8⁺T cells in splenocytes from WT mice, but not from TLR4‐deficient littermates. Intraperitoneal administration of WT C57BL/6 mice with rhCNB resulted in a 50% reduction in LLC tumor growth, but failed to inhibit tumor growth in TLR4^−/− littermates.

Conclusions

The in vivo antitumor and immunomodulatory effects of rhCNB are mediated by the TLR4. This conclusion is important for the further understanding and development of rhCNB as an antitumor drug.

TLR8-Mediated Metabolic Control of Human Treg Function: A Mechanistic Target for Cancer Immunotherapy

Regulatory T (Treg) cells induce an immunosuppressive microenvironment that is a major obstacle for successful tumor immunotherapy. Dissecting the regulatory mechanisms between energy metabolism and functionality in Treg cells will provide insight toward developing novel immunotherapies against cancer. Here we report that human naturally occurring and tumor-associated Treg cells exhibit distinct metabolic profiles with selectivity for glucose metabolism compared with effector T cells. Treg-mediated accelerated glucose consumption induces cellular senescence and suppression of responder T cells through cross-talk. TLR8 signaling selectively inhibits glucose uptake and glycolysis in human Treg cells, resulting in reversal of Treg suppression. Importantly, TLR8 signaling-mediated reprogramming of glucose metabolism and function in human Treg cells can enhance anti-tumor immunity in vivo in a melanoma adoptive transfer T cell therapy model. Our studies identify mechanistic links between innate signaling and metabolic regulation of human Treg suppression, which may be used as a strategy to advance tumor immunotherapy.

Self-associated molecular patterns mediate cancer immune evasion by engaging Siglecs on T cells

First-generation immune checkpoint inhibitors, including anti-CTLA-4 and anti-programmed death 1 (anti-PD-1) antibodies, have led to major clinical progress, yet resistance frequently leads to treatment failure. Thus, new targets acting on T cells are needed. CD33-related sialic acid-binding immunoglobulin-like lectins (Siglecs) are pattern-recognition immune receptors binding to a range of sialoglycan ligands, which appear to function as self-associated molecular patterns (SAMPs) that suppress autoimmune responses. Siglecs are expressed at very low levels on normal T cells, and these receptors were not until recently considered as interesting targets on T cells for cancer immunotherapy. Here, we show an upregulation of Siglecs, including Siglec-9, on tumor-infiltrating T cells from non-small cell lung cancer (NSCLC), colorectal, and ovarian cancer patients. Siglec-9-expressing T cells coexpressed several inhibitory receptors, including PD-1. Targeting of the sialoglycan-SAMP/Siglec pathway in vitro and in vivo resulted in increased anticancer immunity. T cell expression of Siglec-9 in NSCLC patients correlated with reduced survival, and Siglec-9 polymorphisms showed association with the risk of developing lung and colorectal cancer. Our data identify the sialoglycan-SAMP/Siglec pathway as a potential target for improving T cell activation for immunotherapy.

EBV up-regulates PD-L1 on the surface of primary monocytes by increasing ROS and activating TLR signaling and STAT3

Programmed death ligand 1 (PD-L1) (also called B7-H1) is a membrane immune-modulatory protein whose overexpression on the surface of tumor cells as well as APCs impairs T-cell-mediated killing. Viruses that establish chronic infections have developed a number of strategies to escape from immune recognition including the up-regulation of PD-L1. This study shows for the first time that the human oncovirus EBV infects human primary monocytes using HLA-DR and induced a strong up-regulation of PD-L1 expression on their surface. Searching for the underlying mechanism/s leading to this immune suppressive effect, we found that EBV activated TLR signaling, increased intracellular ROS, and phosphorylated STAT3. Targeting these molecules partially reverted PD-L1 up-regulation that correlated with an altered cytokine production and a reduction of monocyte cell survival, strongly impairing the antiviral immune response.

Tumor-derived granzyme B-expressing neutrophils acquire antitumor potential after lipid A treatment

Neutrophils are known to possess both pro- and anti-tumor properties, a feature that could be related to the diversity and plasticity of these cells. Here we explored the hypothesis that under an appropriate environment and stimuli, neutrophils could induce an effective response against tumor cells. In a rat and mouse models, we show that a substantial amount of colon tumor associated-neutrophils (TAN) expressed the cytolytic enzyme granzyme B, which is absent in spleen or blood circulating neutrophils. This TAN population was also found into tumors of patients with colon cancer. Tumor neutrophil infiltration was correlated with an increase of chemokines known to attract neutrophils in both rat models and patients. These cells were involved in a Lipid A analog-mediated colon tumor regression. Mechanistically, treating the rats with the Lipid A analog triggered granzyme B release from neutrophils in tumor cell vicinity, which was correlated to tumor regression. Alteration of granzyme B function in tumor cells decreased the cytotoxic effect of Lipid A in rat and mouse models. Granzyme B expression in neutrophils could be induced by the lipid A analog but also by some of the cytokines that were detected in the tumor microenvironment. These results identify a subpopulation of neutrophils expressing granzyme B that can act as a key player of lipid A-mediated colon cancer regression in rat and mouse models and the molecular mechanisms involved may provide novel approaches for human therapeutic intervention.

Regional anesthesia and analgesia in cancer care: is it time to break the bad news?

PURPOSE OF REVIEW

There is ongoing controversy regarding the tumor-protective effects of regional anesthesia in patients undergoing cancer surgery. Evidence of up-to-date systematic reviews will be presented alongside recent updates on the effects of opioids and local anesthetics.

RECENT FINDINGS

In recent years, the literature regarding the effects of regional anesthesia techniques on cancer recurrence has raised many unanswered questions. Ongoing randomized controlled trials may not be able to shed light on the controversial discussion regarding the tumor protective effects of regional anesthesia because the expected effect size and event rate in those studies may be overstated.Recent more refined animal data, provides no evidence to suggest that opioids promote cancer recurrence or facilitate the development of metastatic disease.In addition, local anesthetics have promising preclinical anticarcinogenic effects that extend beyond their voltage-gated sodium channel blocking properties and could be of therapeutic value.

SUMMARY

Cancer recurrence in patients undergoing surgery remains a global burden. Current evidence suggests that regional techniques, opioid analgesia and local anesthetics in onco-anesthesia may require a tailored individual approach due to the phenotypic and genotypic heterogeneity within and between different tumors. The authors surmise that future or ongoing randomized controlled trials regarding regional anesthesia techniques and cancer outcome may not be able to reproduce clear results, as it will be challenging to prove the efficacy of one single intervention (e.g. regional anesthesia) in an otherwise complex multifactorial perioperative oncological setting.

Pellino-1 confers chemoresistance in lung cancer cells by upregulating cIAP2 through Lys63-mediated polyubiquitination

Pellino-1 is an E3 ubiquitin ligase that mediates immune receptor signaling pathways. The role of Pellino-1 in oncogenesis of lung cancer was investigated in this study. Pellino-1 expression was increased in human lung cancer cell lines compared with non-neoplastic lung cell lines. Pellino-1 overexpression in human lung cancer cells, A549 and H1299 cells, increased the survival and colony forming ability. Pellino-1 overexpression in these cells also conferred resistance to cisplatin- or paclitaxel-induced apoptosis. In contrast, depletion of Pellino-1 decreased the survival of A549 and H1299 cells and sensitized these cells to cisplatin- and paclitaxel-induced apoptosis. Pellino-1 overexpression in A549 and H1299 cells upregulated the expression of inhibitor of apoptosis (IAP) proteins, including cIAP1 and cIAP2, while Pellino-1 depletion downregulated these molecules. Notably, Pellino-1 directly interacted with cIAP2 and stabilized cIAP2 through lysine63-mediated polyubiquitination via its E3 ligase activity. Pellino-1-mediated chemoresistance in lung cancer cells was dependent on the induction of cIAP2. Moreover, a strong positive correlation between Pellino-1 and the cIAP2 expression was observed in human lung adenocarcinoma tissues. Taken together, these results demonstrate that Pellino-1 contributes to lung oncogenesis through the overexpression of cIAP2 and promotion of cell survival and chemoresistance. Pellino-1 might be a novel oncogene and potential therapeutic target in lung cancer.

Adjuvant Probiotics and the Intestinal Microbiome: Enhancing Vaccines and Immunotherapy Outcomes

Immune defence against pathogenic agents comprises the basic premise for the administration of vaccines. Vaccinations have hence prevented millions of infectious illnesses, hospitalizations and mortality. Acquired immunity comprises antibody and cell mediated responses and is characterized by its specificity and memory. Along a similar congruent yet diverse mode of disease prevention, the human host has negotiated from in utero and at birth with the intestinal commensal bacterial cohort to maintain local homeostasis in order to achieve immunological tolerance in the new born. The advent of the Human Microbiome Project has redefined an appreciation of the interactions between the host and bacteria in the intestines from one of a collection of toxic waste to one of a symbiotic existence. Probiotics comprise bacterial genera thought to provide a health benefit to the host. The intestinal microbiota has profound effects on local and extra-intestinal end organ physiology. As such, we further posit that the adjuvant administration of dedicated probiotic formulations can encourage the intestinal commensal cohort to beneficially participate in the intestinal microbiome-intestinal epithelia-innate-cell mediated immunity axes and cell mediated cellular immunity with vaccines aimed at preventing infectious diseases whilst conserving immunological tolerance. The strength of evidence for the positive effect of probiotic administration on acquired immune responses has come from various studies with viral and bacterial vaccines. We posit that the introduction early of probiotics may provide significant beneficial immune outcomes in neonates prior to commencing a vaccination schedule or in elderly adults prior to the administration of vaccinations against influenza viruses.

Circular RNAs: clinical relevance in cancer

Circular RNAs, as recently discovered new endogenous non-coding RNAs, are important gene modulators with critical roles in tumor initiation and malignant progression. With the development of RNA sequencing and microarray technologies, numerous of functional circRNAs have been identified in cancerous tissues and cell lines. Mechanistically, circRNAs function as miRNA sponges, miRNA reservoirs or parental gene expression regulators. In this review, we discuss the properties and functions of circRNAs and their clinical implication as promising biomarkers for cancer research. Moreover, some emerging fields, such as exosome-loaded and immune response-associated circRNAs, are also discussed, suggesting novel insights into the carcinogenesis and therapy associated with these molecules.

TLR2 (-196 to -174 Ins/Del) and TLR3 (1377C>T) as biomarkers for nasopharyngeal cancer in Tunisia

Background/aim: We evaluated the association of TLR2 (-196 to -174 Ins/Del) and TLR3 (1377 C>T) as potential risk factors for nasopharyngeal carcinoma (NPC) in Tunisians. Material and methods: The study subjects comprised 137 NPC patients and 164 cancer-free control subjects. TLR2 genotyping was done by PCR and TLR3 genotyping was performed by PCR-RFLP. Results: Minor allele frequency (MAF) and genotypes of TLR3 (1377 C>T) were comparable between NPC patients and controls. Significantly higher MAF and TLR2-containing Del allele genotypes of TLR2 (-196 to -174 Ins/Del) were seen in NPC patients compared to controls [OR (95% CI) = 2.10 (1.43-3.08), P < 0.001 and OR (95% CI) = 2.07 (1.27-3.37), P = 0.003]. In addition, higher increased NPC risk was associated with the TLR2-Del/Del genotype [OR (95% CI) = 2.74 (1.37-5.48), P = 0.004]. An increased frequency of the Del-T haplotype was seen in NPC cases compared to controls. Conclusion: Our results demonstrate an increased risk of NPC with the TLR2-Del/Del genotype and Del-T TLR2 and TLR3 haplotype, suggesting their potential use as biomarkers to evaluate NPC risk in Tunisians.

Identification of a role for TRIM29 in the control of innate immunity in the respiratory tract

The respiratory tract is heavily populated with innate immune cells, but the mechanisms that control such cells are poorly defined. Here we found that the E3 ubiquitin ligase TRIM29 was a selective regulator of the activation of alveolar macrophages, the expression of type I interferons and the production of proinflammatory cytokines in the lungs. We found that deletion of TRIM29 enhanced macrophage production of type I interferons and protected mice from infection with influenza virus, while challenge of Trim29-/- mice with Haemophilus influenzae resulted in lethal lung inflammation due to massive production of proinflammatory cytokines by macrophages. Mechanistically, we demonstrated that TRIM29 inhibited interferon-regulatory factors and signaling via the transcription factor NF-κB by degrading the adaptor NEMO and that TRIM29 directly bound NEMO and subsequently induced its ubiquitination and proteolytic degradation. These data identify TRIM29 as a key negative regulator of alveolar macrophages and might have important clinical implications for local immunity and immunopathology.

Is the skin a sanctuary for breast cancer cells during treatment with anti-HER2 antibodies?

The occurrence of skin metastases is a common event in patients affected by advanced breast cancer, usually associated with systemic disease progression. Here we describe 2 cases of diffuse cutaneous metastases from HER2-overexpressing breast cancer occurring despite a dramatic response in liver and bone, respectively, during treatment with anti-HER2 antibodies Trastuzumab and Pertuzumab. We discuss the reasons for this discrepancy and suggest a possible implication of impaired immune response in the skin. Future research should provide strategies to overcome the induction of immune privilege in the skin in order to avoid discontinuation of effective treatments.

Regulatory T Cells Suppress Natural Killer Cell Immunity in Patients With Human Cervical Carcinoma

OBJECTIVE

To determine the functional attributes of CD4 CD25 regulatory T (Treg) cells by suppressing natural killer (NK) cell activity in human cervical cancer (CC).

METHODS

Triple-color flow cytometry was used to study the phenotypic expression of CD4 CD25 Treg cells and NK cells in the peripheral blood lymphocytes (PBLs) and tumor-infiltrating lymphocytes (TILs). In vitro coculture assays were performed to illustrate the cytokine immunoregulations between Treg cells and NK cells.

RESULTS

Significantly lower expression ratio of NK cells and higher expression ratio of Treg cells in TILs than PBLs were found. The NK cells displayed significantly higher expression ratio of inhibitory NK receptors (CD158a, CD158b, and NKG2A) and lower expression ratio of activating NK receptors (NKG2D, NKp46, and NKp30) as well as perforin in TILs than PBLs, suggesting the suppressed cytotoxicity of the NK cells in the CC tumor milieu. The expression ratio of transforming growth factor-β1 (TGF-β1) on Treg cells as well as TGF-βRII on Treg cells and NK cells was significantly higher in TILs than PBLs. Further functional in vitro assays demonstrated that NK cell function was suppressed by Treg cells, mimicking the inhibition of TGF-β on NK cells, and interleukin-2/interleukin-15 stimulation was able to restore the NK cell activity.

CONCLUSIONS

These findings indicate that Treg cells in TILs may abrogate NK cell cytotoxicity through TGF-β pathway, and therefore, Treg cell elimination may enhance NK cell activity and be a novel therapeutic strategy for CC.

Toll-like receptors and cutaneous melanoma

Innate immune cells recognize highly conserved pathogen-associated molecular patterns (PAMPs) via pattern recognition receptors (PRRs). Previous studies have demonstrated that PRRs also recognize endogenous molecules, termed damage-associated molecular patterns (DAMPs) that are derived from damaged cells. PRRs include Toll-like receptors (TLRs), scavenger receptors, C-type lectin receptors and nucleotide oligomerization domain-like receptors. To date, 10 TLRs have been identified in humans and each receptor responds to a different ligand. The recognition of PAMPS or DAMPs by TLRs leads to the activation of signaling pathways and cellular responses with subsequent pro-inflammatory cytokine release, phagocytosis and antigen presentation. In the human skin, TLRs are expressed by keratinocytes and melanocytes: The main cells from which skin cancers arise. TLRs 1-6 and 9 are expressed in keratinocytes, while TLRs 2-5, 7, 9 and 10 have been identified in melanocytes. It is hypothesized that TLRs may present a target for melanoma therapies. In this review, the involvement of TLRs in the pathogenesis and treatment of melanoma was discussed.

MicroRNA-181b negatively regulates the proliferation of human epidermal keratinocytes in psoriasis through targeting TLR4

Our study aims to explore the role of microRNA‐181b (miR‐181b) and TLR in the regulation of cell proliferation of human epidermal keratinocytes (HEKs) in psoriasis. Twenty‐eight patients diagnosed with psoriasis vulgaris were selected as a case group with their lesional and non‐lesional skin tissues collected. A control group consisted of 20 patients who underwent plastic surgery with their healthy skin tissues collected. Real‐time quantitative fluorescence polymerase chain reaction (RT‐qPCR), in situ hybridization and immunohistochemistry were used to detect the expressions of miR‐181b and TLR4 in HEKs of healthy skin, psoriatic lesional skin and non‐lesional skin respectively. The 3′ untranslated region (3′UTR) of TLR4 combined with miR‐181b was verified by a dual‐luciferase reporter assay. Western blotting and bromodeoxyuridine were applied for corresponding detection of TLR4 expression and cell mitosis. The expression of miR‐181b in HEKs of psoriatic lesional skin was less than healthy skin and psoriatic non‐lesional skin. In psoriatic lesional and non‐lesional skin, TLR4‐positive cell rates and the number of positive cells per square millimetre were higher than healthy skin. The dual‐luciferase reporter assay verified that miR‐181b targets TLR4. HEKs transfected with miR‐181b mimics had decreased expression of TLR4, along with the decrease of mitotic indexes and Brdu labelling indexes. However, HEKs transfected with miR‐181b inhibitors showed increased TLR4 expression, mitotic indexes and Brdu labelling indexes. HEKs transfected with both miR‐181b inhibitors and siTLR4 had decreased mitotic indexes and Brdu labelling indexes. These results indicate that miR‐181b can negatively regulate the proliferation of HEKs in psoriasis by targeting TLR4.

Cellular uptake of exogenous calcineurin B is dependent on TLR4/MD2/CD14 complexes, and CnB is an endogenous ligand of TLR4

Our previous research showed that recombinant calcineurin B (rhCnB) stimulates cytokine secretion by immune cells, probably through TLR4. Exogenous CnB can be incorporated into many different tumour cells in vitro, but the mode of uptake and receptors required remain unknown. Here, we report that exogenous CnB is taken up by cells in a time- and concentration-dependent manner via clathrin-dependent receptor-mediated internalization. Our findings further confirm that uptake is mediated by the TLR4/MD2 complex together with the co-receptor CD14. The MST results revealed a high affinity between CnB and the TLR4 receptor complex. No binding was detected between CnB and LPS. CnB inhibited the uptake of LPS, and LPS also inhibited the uptake of CnB. These results indicate that the uptake of exogenous CnB did not occur through LPS and that CnB was not a chaperone of LPS. Thus, we conclude that TLR4 receptor complexes were required for the recognition and internalization of exogenous CnB. CnB could be a potential endogenous ligand of TLR4 and function as an agonist of TLR4. These properties of CnB support its potential for development as an anti-cancer drug.

The protective effects of bone marrow-derived mesenchymal stem cell (BMSC) on LPS-induced acute lung injury via TLR3-mediated IFNs, MAPK and NF-κB signaling pathways

The study attempted to clarify the protective role of bone marrow-derived mesenchymal stem cell (BMSC) transplantation on LPS-induced acute lung injury (ALI) of rats. BMSC were obtained from bone marrow of rat, cultured and proliferated in vitro. Rats of ALI were established through lipopolysaccharide (LPS) administration. Male rats were allocated to control group, ALI group and BMSC, transplantation group. Rats were sacrificed after BMSC injection after 12h, 24h and 48h. Here we investigated the role of BMSC in LPS-induced alveolar macrophages to further demonstrate the mechanism of BMSC to lung injury. TLR3, a member of Toll-like receptor family, has been found in macrophages and the cell surface. In our study, first BMSC successfully reversed LPS-induced lung injury by hematoxylin-eosin (H&E) staining, ameliorated apoptosis via TUNEL and flow cytometer analysis, as well as improved cell structure. And then, western blot, quantitative real-time PCR, immunohistochemistry and immunofluorescence analysis were used to confirm that TLR3 was significantly down-regulated for BMSC treatment. Subsequently, TRIF and RIP1, down-streaming signals of TLR3, were inhibited greatly, leading to TRAF3, MAPK as well as NF-κB inactivity. Our results indicated that BMSC transplantation group displayed inhibitory effects on interferon (IFNs) levels via TLR3 in LPS-induced ALI and preventive effects on inflammation response via TLR3-regualted MAPK and NF-κB signaling pathway in LPS-induced lung injury. The present study indicated that BMSC could display protective effects on LPS-induced ALI and provide an experimental basis for clinical therapy.

Lipopolysaccharide (LPS) Promotes Apoptosis in Human Breast Epithelial × Breast Cancer Hybrids, but Not in Parental Cells

Toll-like receptors (TLRs) belong to the group of pathogen recognition receptors known to play a crucial role in the innate immune system. In cancer, TLR expression is still debated controversially due to contradictory results reporting that both induction of apoptosis as well as tumor progression could depend on TLR signaling, whereby recent data rather indicate a pro-tumorigenic effect. The biological phenomenon of cell fusion has been associated with cancer progression due to findings revealing that fusion-derived hybrid cells could exhibit properties like an increased metastatogenic capacity and an increased drug resistance. Thus, M13MDA435 hybrid cell lines, which derived from spontaneous fusion events between human M13SV1-EGFP-Neo breast epithelial cells and human MDA-MB-435-Hyg breast cancer cells, were investigated. Cultivation of cells in the presence of the TLR4 ligand LPS potently induced apoptosis in all hybrid clones, but not in parental cells, which was most likely attributed to differential kinetics of the TLR4 signal transduction cascade. Activation of this pathway concomitant with NF-κB nuclear translocation and TNF-α expression was solely observed in hybrid cells. However, induction of LPS mediated apoptosis was not TNF-α dependent since TNF-α neutralization was not correlated to a decreased amount of dead cells. In addition to TNF-α, LPS also caused IFN-β expression in hybrid clones 1 and 3. Interestingly, hybrid clones differ in the mode of LPS induced apoptosis. While neutralization of IFN-β was sufficient to impair the LPS induced apoptosis in M13MDA435-1 and -3 hybrids, the amount of apoptotic M13MDA435-2 and -4 hybrid cells remained unchanged in the presence of neutralizing IFN-β antibodies. In summary, the fusion of non-LPS susceptible parental human breast epithelial cells and human breast cancer cells gave rise to LPS susceptible hybrid cells, which is in view with the cell fusion hypothesis that hybrid cells could exhibit novel properties.

Immune biomarkers PD-1/PD-L1 and TLR3 in malignant pleural mesotheliomas

Malignant pleural mesothelioma (MPM) is an aggressive tumor with no effective therapy. However PD-L1/PD-1 immunity checkpoint therapies gave encouraging results; TLR3 is a programmed death factor, which triggering up-regulates PD-L1. As PD-1/PD-L1 blocking antibodies could restore antitumor immune responses alone or in combination with TLR3 agonists, we investigated PD-L1/PD-1 and TLR3 expressions in MPM to select patients for immunotherapy. Sixty-eight pleural surgical specimens, including 58 MPM (epithelioid, n = 34; biphasic, n = 11; sarcomatoid, n = 13) and 10 benign lesions, were studied. PD-L1 expression was assessed using E1L3N and SP142 clones in tumor cells (TCs) and in tumor-infiltrating lymphocytes (TILs) (positivity threshold of 1%), and compared with overall survival. PD-1, CD3 and CD8 expression by TILs, and TLR3 expression by TCs were analyzed concomitantly. PD-L1 was more expressed by sarcomatoid subtype than by other MPM (62% versus 23% and 9% for E1L3N; 38% versus 11% for SP142) (P = .01 and .04, respectively). Specificity and sensitivity of E1L3N and SP142 were of 53% and 98%, and 90% and 86%, respectively. PD-L1 expression by TILs and TCs correlated for SP142 (P = .023), and PD-L1 SP142 expression by TCs was associated with shorter overall survival (P = .016). TLR3 was expressed in most MPM, but weakly in sarcomatoid MPM. We confirm by comparing two commercially available antibodies that PD-L1 expression is higher in sarcomatoid MPM and correlates with a shorter survival. Whereas TLR3 agonists could be tested in MPM expressing TLR3, the sarcomatoid subtype could benefit from anti-PD-L1/PD-1 therapies alone or in combination.

Modulating the innate immune activity in murine tumor microenvironment by a combination of inducer molecules attached to microparticles

Targeted cancer immunotherapy is challenging due to the cellular diversity and imposed immune tolerance in the tumor microenvironment (TME). A promising route to overcome those drawbacks may be by activating innate immune cells (IIC) in the TME, toward tumor destruction. Studies have shown the ability to "re-educate" pro-tumor-activated IIC toward antitumor responses. The current research aims to stimulate such activation using a combination of innate activators loaded onto microparticles (MP). Four inducers of Toll-like receptors 4 and 7, complement C5a receptor (C5aR) and gamma Fc receptor and their combinations were loaded on MP, and their influence on immune cell activation evaluated. MP stimulation of immune cell activation was tested in vitro and in vivo using a subcutaneous B16-F10 melanoma model induced in C57BL6 mice. Exposure to the TLR4 ligand lipopolysaccharide (LPS) bound to MP-induced acute inflammatory cytokine and chemokine activity in vitro and in vivo, with the elevation of CD45(+) leukocytes in particular GR-1(+) neutrophils and F4/80 macrophages in the TME. Nevertheless, LPS alone on MP was insufficient to significantly delay tumor progression. LPS combined with the C5aR ligand C5a-pep on the same MP resulted in a similar inflammation activation pattern. However, interleukin-10 levels were lower, and tumor growth was significantly delayed. Mixtures of these two ligands on separate MP did not yield the same cytokine activation pattern, demonstrating the importance of the cells' dual activation. The results suggest that combining inducers of distinct innate immune activation pathways holds promise for successful redirection of TME-residing IIC toward anti-tumoral activation.

Toll-like receptor 4 gene polymorphisms and susceptibility to colorectal cancer: a meta-analysis and review

INTRODUCTION

Many case-control studies have investigated the association between toll-like receptor 4 (TLR4) Asp299Gly and Thr399Ile polymorphisms and risk of colorectal cancer (CRC). However, published data are still conflicting.

MATERIAL AND METHODS

A systematic search was conducted in the electronic databases of PubMed, MEDLINE, EMBASE, Web of Science and CNKI between 2000 and 2014. The associations between TLR4 polymorphisms and CRC susceptibility were assessed by pooled odds ratios (ORs) and 95% confidence intervals (95% CI) in fixed or random effects models.

RESULTS

In total nine case-control studies were identified in this meta-analysis. For TLR4 Asp299Gly polymorphism, 9 studies included 1198 cases and 1290 controls. The GG genotype carriers had higher risk for developing CRC than AA + GA genotype carriers (OR = 1.95, 95% CI: 1.00-3.77, p = 0.05). No association was found in other genetic models (p > 0.05). Analysis stratified by ethnicity showed no association in any genetic models among the Asian or Caucasian population. For TLR4 Thr399Ile polymorphism, 6 studies contained 619 cases and 632 controls. The overall analysis showed significantly increased risk in TT homozygote carriers compared to CC homozygote (OR = 4.99, 95% CI: 1.41-17.65, p = 0.01) and C carriers (TC + CC) (OR = 4.50, 95% CI: 1.27-15.87, p = 0.02). In terms of analyses stratified by race, a significant association was found in each genetic model among the Asian population, rather than the Caucasian group.

CONCLUSIONS

The GG homozygote carriers of TLR4 Asp299Gly and TT homozygote carriers of TLR4 Thr399Ile polymorphisms might be correlated with an increased risk of CRC, suggesting they may serve as genetic risk factors for CRC.

TLR8 signaling enhances tumor immunity by preventing tumor-induced T-cell senescence

Accumulating evidence suggests the immunosuppressive microenvironments created by malignant tumors represent a major obstacle for effective anti-tumor immunity. A better understanding of the suppressive mechanisms mediated by tumor microenvironments and the development of strategies to reverse the immune suppression are major challenges for the success of tumor immunotherapy. Here, we report that human tumor cells can induce senescence in naïve/effector T cells, exhibiting potent suppressive function in vitro and in vivo. We further show that tumor-derived endogenous cyclic adenosine monophosphate (cAMP) is responsible for the induction of T-cell senescence. Importantly, activation of TLR8 signaling in tumor cells can block the induction and reverse the suppression of senescent naïve and tumor-specific T cells in vitro and in vivo, resulting in enhanced anti-tumor immunity. These studies identify a novel mechanism of human tumor-mediated immune suppression and provide a new strategy to reverse tumor immunosuppressive effects for tumor immunotherapy.

Harnessing the Microbiome to Enhance Cancer Immunotherapy

The microbiota plays a key role in regulating the innate and adaptive immune system. Herein, we review the immunological aspects of the microbiota in tumor immunity in mice and man, with a focus on toll-like receptor (TLR) agonists, vaccines, checkpoint modulators, chemotherapy, and adoptive T cell transfer (ACT) therapies. We propose innovative treatments that may safely harness the microbiota to enhance T cell-based therapies in cancer patients. Finally, we highlight recent developments in tumor immunotherapy, particularly novel ways to modulate the microbiome and memory T cell responses to human malignancies.

Targeting Toll-like receptor 2 inhibits growth of head and neck squamous cell carcinoma

Infection-driven inflammation has been proposed to be involved in the tumorigenesis of head and neck squamous cell carcinoma (HNSCC). Oral HNSCC is often colonized with microbes such as gram-positive bacteria and yeast, where ligands derived from their wall components have been shown to specifically bind to Toll-like receptor 2 (TLR2). Although TLR2 has been described to be expressed in oral HNSCC, its function has not been well characterized. Here, we show the expression of TLR2 in both HNSCC cell lines and primary patient-derived HNSCC xenograft tumors. Activation of TLR2 with a yeast-derived ligand of TLR2, zymosan, promoted organoid formation in an ex vivo model of tumor growth, while blockade with anti-TLR2 antibodies inhibited organoid formation. Zymosan also induced phosphorylation of ERK and the p65 subunit of NF-κB, which was inhibited in the presence of anti-TLR2 antibodies, indicating that this receptor is functional in HNSCC and that the signaling through these pathways is intact. TLR2 blockade also inhibited growth of human xenografted tumors in immunodeficient mice. In summary, our data show that TLR2 is a functional receptor expressed in human HNSCC that plays a direct pro-tumorigenic role, and that it can be therapeutically targeted with blocking antibodies to reduce tumor growth.

Involvement of Toll-like receptors in cervical cancer susceptibility among Tunisian women

Previous studies underscored the importance of genetic factors in the pathogenesis of certain cancers, including cervical cancer. Epidemiological evidence supports an association between specific polymorphisms of Toll-like receptors (TLR) with several human pathological states, including cervical cancer. The aim of this study was to investigate the link between specific gene variants in TLR2 (-196 to -174 del), TLR3 (c.1377 C>T), TLR4 (Asp299Gly), and TLR9 (2848 G>A) and susceptibility to cervical cancer in Tunisian women. Study subjects comprised 122 women with histopathologically-confirmed cervical cancer, and 260 unrelated age- and ethnically-matched healthy females, who served as controls. TLR genotyping was done using PCR-restriction fragment length polymorphism. The C/C genotype of TLR3 (c.1377 C>T) is associated with cervical cancer susceptibility (OR: 1.71, CI: 1.08-2.70). For TLR4 (Asp299Gly), the Asp/Asp genotype and the Asp allele were associated with higher risk of developing cervical cancer (OR: 4.95, CI: 1.97-13.22) and (OR: 5.17, CI: 2.11-13.50) respectively. We demonstrated no association between the TLR2 (-196 to -174 del) and the TLR 9 (2848 G>A) polymorphisms and the susceptibility of cervical cancer among Tunisian women. However, the C/C genotype for the TLR3 (c.1377 C>T) polymorphism and the Asp/Asp genotype and the Asp allele for (Asp299Gly) TLR4 polymorphism were found to be associated with a higher risk of cervical cancer.

A functional variant at miR-34a binding site in toll-like receptor 4 gene alters susceptibility to hepatocellular carcinoma in a Chinese Han population

Toll-like receptor 4 (TLR4) plays a key role in prompting the innate or immediate response. A growing body of evidence suggests that genetic variants of TLR4 gene were associated with the development of cancers. This study aimed to investigate the relationship of a functional variant (rs1057317) at microRNA-34a (miR-34a) binding site in toll-like receptor 4 gene and the risk of hepatocellular carcinoma. A single center-based case-control study was conducted. In this study, the polymerase chain reaction (PCR) and direct sequencing were used to genotype sequence variants of TLR4 in 426 hepatocellular carcinoma cases and 438 controls. The modification of rs1057317 on the binding of hsa-miR-34a to TLR4 messenger RNA (mRNA) was measured by luciferase activity assay. Individuals carrying the AA genotypes for the rs1057317 were associated significantly with increased risk of hepatocellular carcinoma comparing with those carrying wild-type homozygous CC genotypes (adjusted odds ratio [OR] by sex and age, from 1.116 to 2.452, P = 0.013). The activity of the reporter vector was lower in the reporter vector carrying C allele than the reporter vector carrying A allele. Furthermore, the expression of TLR4 was detected in the peripheral blood mononucleated cell of hepatocellular carcinoma (HCC) patients, suggesting that mRNA and protein levels of TLR4 might be associated with SNP rs1057317. Collectively, these results suggested that the risk of hepatocellular carcinoma was associated with a functional variant at miR-34a binding site in toll-like receptor 4 gene. miR-34a/TLR4 axis may play an important role in the development of hepatocellular carcinoma.

Selective targeting of Toll-like receptors and OX40 inhibit regulatory T-cell function in follicular lymphoma

Immunotherapeutic strategies are promising approaches for the treatment of follicular lymphoma (FL). However, their efficacy may be limited by immunosuppressive elements in the immune system and tumor microenvironment. Therefore, strategies to reverse the effects of the immunosuppressive elements are needed. We observed that regulatory T cells (Tregs) were increased in the peripheral blood at diagnosis and persisted in high numbers after induction of clinical remission with a cyclophosphamide and doxorubicin-containing chemotherapy regimen in FL patients. High levels of peripheral blood Tregs prior to therapy were associated with decreased progression-free survival in FL patients treated with either chemotherapy or combination immunotherapy that targeted CD20 and PD-1 with monoclonal antibodies rituximab and pidilizumab, respectively. Intratumoral and peripheral blood Tregs potently suppressed autologous antitumor effector T cells in FL. However, the effects of FL Tregs could be reversed by triggering Toll-like receptors (TLR) with TLR ligands Pam3 CSK4 (TLR 1/2), flagellin (TLR 5), and CpG-B (TLR 9), and/or OX40. The TLR ligands synergized with each other as well as OX40 signaling to inhibit Tregs. Furthermore, they restored the function of FL tumor-specific effector T cells. Our results suggest that a state of tolerance exists in FL patients at diagnosis and after induction of clinical remission, and agents that activate TLRs 1/2, 5, and 9, and OX40 may serve as adjuvants to enhance the efficacy of antitumor immunotherapeutic strategies and preventive vaccines against infectious diseases in these patients.