Toll-like receptor 5 gene polymorphism is associated with breast cancer susceptibility

Interactions between microbiota and uterine corpus endometrial cancer: A bioinformatic investigation of potential immunotherapy

Microorganisms in the gut and other niches may contribute to carcinogenesis while also altering cancer immune surveillance and therapeutic response. However, determining the impact of genetic variations and interplay with intestinal microbes' environment is difficult and unanswered. Here, we examined the frequency of thirteen mutant genes that caused aberrant gut in thirty different types of cancer using The Cancer Genomic Atlas (TCGA) database. Substantially, our findings show that all these mutated genes are quite frequent in uterine corpus endometrial cancer (UCEC). Further, these mutant genes are implicated in the infiltration of different subset of immune cells within the Tumor Microenvironment (TME) of UCEC patients. The top-ranking mutant genes that promote immune cell invasion into the TME of UCEC patients were PGLYRP2, OLFM4, and TLR5. In this regard, we used the same deconvolution of the TCGA database to analyze the microbiome that have a strong association with immune cells invasion with TME of UCEC patients. Several bacteria and viruses have been linked to the invasion of immune cells, such as B cell memory and T cell regulatory (Tregs), into the TME of UCEC patients. As a result, our findings pave the way for future research into generating novel immunizations against bacteria or viruses as immunotherapy for UCEC patients.

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.

Toll-like receptors in health and disease

Toll-like receptors (TLRs) are inflammatory triggers and belong to a family of pattern recognition receptors (PRRs) that are central to the regulation of host protective adaptive immune responses. Activation of TLRs in innate immune myeloid cells directs lymphocytes to produce the most appropriate effector responses to eliminate infection and maintain homeostasis of the body's internal environment. Inappropriate TLR stimulation can lead to the development of general autoimmune diseases as well as chronic and acute inflammation, and even cancer. Therefore, TLRs are expected to be targets for therapeutic treatment of inflammation-related diseases, autoimmune diseases, microbial infections, and human cancers. This review summarizes the recent discoveries in the molecular and structural biology of TLRs. The role of different TLR signaling pathways in inflammatory diseases, autoimmune diseases such as diabetes, cardiovascular diseases, respiratory diseases, digestive diseases, and even cancers (oral, gastric, breast, colorectal) is highlighted and summarizes new drugs and related clinical treatments in clinical trials, providing an overview of the potential and prospects of TLRs for the treatment of TLR-related diseases.

Role of toll-like receptor in the pathogenesis of oral cancer

Toll-like receptors are important molecules of innate immunity. They are known as pattern recognition receptors. They recognise certain molecules known as pathogen-associated molecular pattern on a pathogen and release chemicals that causes inflammation. Toll-like receptors (TLR) help in the removal of the infected cell and thus stop the spread of infection and are being studied for their association with cancer. Oral carcinoma has emerged as a major problem of our country today; it is found ranks first in men and third in women. Toll-like receptors have been implicated in the development of cancer. Certain polymorphisms in toll-like receptor can make a cell more susceptible to develop oral cancer. The identification of toll-like receptors and the different genotypes that are involved in the development of cancer can be utilised for using them as biomarkers of the disease. The study revealed that toll-like receptors like TLR7 and TLR5 are found to have a role in suppression of oral cancer while toll-like receptors like TLR4 and TLR2 are found to be associated with the progression of oral cancer. Toll-like receptors can turn out as important target molecules in the future in designing therapeutic strategies for oral cancer.

Innate Immune Program in Formation of Tumor-Initiating Cells from Cells-of-Origin of Breast, Prostate, and Ovarian Cancers

Tumor-initiating cells (TICs), also known as cancer stem cells (CSCs), are cancer cells that can initiate a tumor, possess self-renewal capacity, and can contribute to tumor heterogeneity. TICs/CSCs are developed from their cells-of-origin. In breast, prostate, and ovarian cancers, progenitor cells for mammary alveolar cells, prostate luminal (secretory) cells, and fallopian tube secretory cells are the preferred cellular origins for their corresponding cancer types. These luminal progenitors (LPs) express common innate immune program (e.g., Toll-like receptor (TLR) signaling)-related genes. Microbes such as bacteria are now found in breast, prostate, and fallopian tube tissues and their corresponding cancer types, raising the possibility that their LPs may sense the presence of microbes and trigger their innate immune/TLR pathways, leading to an inflammatory microenvironment. Crosstalk between immune cells (e.g., macrophages) and affected epithelial cells (e.g., LPs) may eventually contribute to formation of TICs/CSCs from their corresponding LPs, in part via STAT3 and/or NFκB pathways. As such, TICs/CSCs can inherit expression of innate-immunity/TLR-pathway-related genes from their cells-of-origin; the innate immune program may also represent their unique vulnerability, which can be explored therapeutically (e.g., by enhancing immunotherapy via augmenting TLR signaling).

The therapeutic potential of targeting Toll like receptor pathway in breast cancer

The toll-like receptor (TLR) signaling pathway plays a key role in inducing immune responses and were shown to be expressed in immune cells and tumor cells, and is involved in the progression of several malignancies including breast cancer. These findings provide a proof of the concept of targeting this pathway as a potential therapeutic option in the treatment of breast cancer. Moreover, there is a growing body of data showing the activation of TLRs in the tumor microenvironment and its dual function as anti-tumoral (dendritic T and natural killer cells activation) or pro-tumoral activity (cell proliferation, and drug resistance). Several agents have been developed for targeting of this pathway and one of these inhibitors, called Bacillus Calmette-Guerin (an agonist of TLR2 and TLR4), is recently being approved by FDA for immunotherapy of bladder cancer. This review summarizes the current knowledge of the mechanisms of action of TLR pathways in the development/progression of cancer for a better management of this disease.

Fibronectin Functions as a Selective Agonist for Distinct Toll-like Receptors in Triple-Negative Breast Cancer

The microenvironment of tumors is characterized by structural changes in the fibronectin matrix, which include increased deposition of the EDA isoform of fibronectin and the unfolding of the fibronectin Type III domains. The impact of these structural changes on tumor progression is not well understood. The fibronectin EDA (FnEDA) domain and the partially unfolded first Type III domain of fibronectin (FnIII-1c) have been identified as endogenous damage-associated molecular pattern molecules (DAMPs), which induce innate immune responses by serving as agonists for Toll-Like Receptors (TLRs). Using two triple-negative breast cancer (TNBC) cell lines MDA-MB-468 and MDA-MB-231, we show that FnEDA and FnIII-1c induce the pro-tumorigenic cytokine, IL-8, by serving as agonists for TLR5 and TLR2, the canonical receptors for bacterial flagellin and lipoprotein, respectively. We also find that FnIII-1c is not recognized by MDA-MB-468 cells but is recognized by MDA-MB-231 cells, suggesting a cell type rather than ligand specific utilization of TLRs. As IL-8 plays a major role in the progression of TNBC, these studies suggest that tumor-induced structural changes in the fibronectin matrix promote an inflammatory microenvironment conducive to metastatic progression.

Down-Regulation of Toll-Like Receptor 5 (TLR5) Increased VEGFR Expression in Triple Negative Breast Cancer (TNBC) Based on Radionuclide Imaging

In this study, GFP-tagged TNBC 4T1 cells with down-regulated TLR5 expression (TLR5- 4T1) and normal TLR5 expression (TLR5+ 4T1) were constructed, respectively. RT-PCR and Western blot studies showed that down-regulation of TLR5 obviously increased the expression of VEGFR in 4T1 cells. Highly stable radio-probes 125I-anti-TLR5 mAb/125I-VEGF/125I-IgG were obtained with labeling rates over 85% and radiochemical purities above 90%. Among these three probes, 125I-anti-TLR5 mAb and 125I-VEGF were used for specifically imaging TNBC, while 125I-IgG was used for comparison. Whole-body phosphorus autoradiography showed clear imaging at 48 h after injection of 125I-anti-TLR5 mAb and 125I-VEGF also provided clear imaging at 24 h. Biodistribution study demonstrated a higher tumor uptake of 125I-anti-TLR5 mAb in TLR5+ group compared with that in TLR5- group (P < 0.05), whereas tumor uptake of 125I-VEGF in TLR5+ group was lower than that in the TLR5- group (P < 0.05). Immunohistochemical staining suggested that the expression of TLR5 was lower, whereas the expression of VEGFR, CD31, and MVD (microvessel density) was higher in TLR5- tumor-bearing mice. In summary, the down-regulation of TLR5 in TNBC promoted the VEGFR expression and angiogenesis, resulting in the proliferation of TNBC cells. TLR5/VEGF might be a better indicator for monitoring the development of TNBC.

The effect of allicin on cell proliferation and apoptosis compared to blank control and cis-platinum in oral tongue squamous cell carcinoma

Background

Oral tongue squamous cell carcinoma (OTSCC) has aggressive clinical behavior with poor prognosis. Allicin plays a tumor-suppressive role in various cancers, although the role of allicin in OTSCC is unknown. We aimed to investigate the effect of allicin on cell proliferation and apoptosis compared to blank control and cis-platinum in OTSCC.

Methods

Tca-8113 and SCC-25 cells were treated with non-stimulated control, 12.5 µg/mL allicin, 25 µg/mL allicin, 50 µg/mL allicin, and 40 µg/mL cis-platinum, which were divided into blank control, allicin 12.5 µg/mL, allicin 25 µg/mL, allicin 50 µg/mL, and cis-platinum 40 µg/mL groups, respectively. Cell proliferation was determined by the Cell Counting Kit-8 assay. Cell apoptosis was detected by annexin V/propidium iodide and Western blot assays.

Results

In Tca-8113 and SCC-25 cells, cell proliferation was inhibited by 40 μg/mL cis-platinum, 12.5 μg/mL allicin, 25 μg/mL allicin, and 50 μg/mL allicin. Cell apoptosis was promoted by 40 μg/mL cis-platinum, 12.5 μg/mL allicin, 25 μg/mL allicin, and 50 μg/mL allicin, while compared to 40 μg/mL cis-platinum, it was increased by 50 μg/mL allicin. Western blot assay revealed that expression of pro-apoptosis protein Bax and C-Caspase 3 increased, but apoptosis-inhibitory protein Bcl-2 expression decreased with 40 μg/mL cis-platinum, 12.5 μg/mL allicin, 25 μg/mL allicin, and 50 μg/mL allicin, while compared to 40 μg/mL cis-platinum, Bax and C-Caspase 3 expression was increased by 50 μg/mL allicin.

Conclusion

Allicin was shown to have good efficacy in repressing cell proliferation as well as facilitating cell apoptosis in OTSCC.

Targeting Toll like Receptors in Cancer: Role of TLR Natural and Synthetic Modulators

Background:

Toll like receptors (TLRs) are a group of transmembrane receptors belonging to the broad class pattern recognition receptors (PRR), involved in recognition of Pathogen Associated Molecular Patterns (PAMPs) thereby inducing an immune response. Apart from these exogenous PAMPs, numerous endogenous PAMPs are also ligands for various TLRs thereby activating the TLR dependent immune response, subsequently leading to the onset of an inflammatory response. Prolonged activation of TLR by these endogenous PAMPs leads to chronic inflammatory insults to the body and which in turn alters the proliferative patterns of the cells, which ultimately leads to the development of cancer.

Objectives:

The present review aims to provide a detailed outline of the differential roles of various TLRs in cancer and the possible use of them as a therapeutic target.

Methods:

Data were collected from PubMed/Sciencedirect/Web of Science database and sorted; the latest literature on TLRs was incorporated in the review.

Results:

Among the different TLRs, few are reported to be anti-neoplastic, which controls the cell growth and multiplication in response to the endogenous signals. On the contrary, numerous studies have reported the procarcinogenic potentials of TLRs. Hence, TLRs have emerged as a potential target for the prevention and treatment of various types of cancers. Several molecules, such as monoclonal antibodies, small molecule inhibitors and natural products have shown promising anticancer potential by effectively modulating the TLR signalling.

Conclusion:

Toll-like receptors play vital roles in the process of carcinogenesis, hence TLR targeting is a promising approach for cancer prevention.

Toll-like Receptors as a Novel Therapeutic Target for Natural Products Against Chronic Diseases

Toll-like receptors (TLR) are one among the initial responders of the immune system which participate in the activation inflammatory processes. Several different types of TLR such as TLR2, TLR4, TLR7 and TLR9 have been identified in various cell types, each having distinct ligands like lipids, lipoproteins, nucleic acids and proteins. Though its prime concern is xenobiotic defences, TLR signalling has also recognized as an activator of inflammation and associated development of chronic degenerative disorders (CDDs) including obesity, type 2 diabetes mellitus (T2DM), fatty liver disease, cardiovascular and neurodegenerative disorders as well as various types of cancers. Numerous drugs are in use to prevent these disorders, which specifically inhibit different pathways associated with the development of CDDs. Compared to these drug targets, inhibition of TLR, which specifically responsible for the inflammatory insults has proven to be a better drug target. Several natural products have emerged as inhibitors of CDDs, which specifically targets TLR signalling, among these, many are in the clinical trials. This review is intended to summarize the recent progress on TLR association with CDDs and to list possible use of natural products, their combinations and their synthetic derivative in the prevention of TLR-driven CDD development.

Toll-like receptors as a therapeutic target in cancer, infections and inflammatory diseases

Toll-like receptors (TLRs) are widely expressed pattern recognition receptors that bind to conserved molecular patterns expressed by pathogens and damaged cells. After recognition, activated TLRs induce the expression of various proinflammatory and antiviral molecules. Thus, TLRs are potential targets for treatment strategies aimed at boosting the adaptive immune response to vaccines, controlling infections, enhancing immune responses during tumor treatment and attenuating immune responses in inflammatory disorders. This Special Report examines the potential of TLRs as targets for the treatment of cancer, infections and inflammatory diseases. Here, we make a particular emphasis on molecules capable of modulating TLRs and their therapeutic applications.

TLR5: A prognostic and monitoring indicator for triple-negative breast cancer

A novel, highly selective biomarker is urgently needed to predict and monitor triple-negative breast cancer (TNBC) because targeting molecules are not currently available. Although associated with various malignant tumors, the role of toll-like receptor 5 (TLR5) in TNBC remains uncertain. We aimed to define the effects of TLR5 in TNBC to determine whether it could serve as a prognostic and monitoring indicator for TNBC. We established TNBC cell line 4T1 with low TLR5 expression (GFP tag; TLR5⁻ 4T1) and with normal TLR5 expression (GFP tag; TLR5⁺ 4T1) using lentivirus-shRNA-TLR5 knockdown transfection and negative lentivirus transfection, respectively. Detected by western blot and qPCR, we found knockdown of TLR5 resulted in decreased expression of TLR5 and E-cadherin and increased expression of N-cadherin, vimentin, fibronectin, TRAF6, SOX2, and Twist1, which were related to EMT (epithelial–mesenchymal transition). In addition, downregulation of TLR5 increased the invasion and migration of 4T1 cells in vitro, which were investigated by CCK-8 and wound healing, as well as transwell assay and colony formation. Furthermore, the metastatic ability of TLR5⁻ 4T1 cells to the lungs was also increased compared to TLR5⁺ 4T1 cells in vivo. To verify the effect of TLR5 as a monitor indicator, mice bearing TLR5⁺ and TLR5⁻ 4T1 tumors injected with ¹²⁵I-anti-TLR5 mAb or isotype ¹²⁵I-IgG were assessed by whole body phosphor-autoradiography and fluorescence imaging in vivo. Phosphor-autoradiography of model mice revealed early tumors at 6 days after inoculation with TLR5⁺ 4T1, but not TLR5⁻ 4T1 cells. Intratumoral accumulation of radioactivity positively correlated with TLR5 expression, and fluorescence imaging in vivo revealed both TLR5⁺ and TLR5⁻ 4T1 tumors. Our results suggested that downregulation of TLR5 in TNBC increased tumor invasiveness and EMT expression via TRAF6 and SOX2 pathway and TLR5 could serve as a prognostic and monitoring indicator for TLR5-positive tumors.

TLR5 is a new reporter for triple-negative breast cancer indicated by radioimmunoimaging and fluorescent staining

Triple-negative breast cancer (TNBC) is a highly aggressive tumour that lacks marker for targeted diagnosis. Recently, it was reported that toll-like receptor 5 (TLR5) was associated with some kind of tumours, especially in TNBC, but whether it could be used as a non-invasive monitoring target is not fully understood. Here, we established TLR5- 4T1 cell line with lentivirus-shRNA-TLR5 knock-down transfection (with tag GFP, green fluorescent protein, TLR5- 4T1) and control TLR5+ 4T1 cell line with negative control lentivirus transfection. The effect of TLR5 down-regulation was detected with qPCR and Western blot. 125 I-anti-TLR5 mAb and control isotype 125 I-IgG were prepared and injected to TLR5+/- 4T1-bearing mice models, respectively. Whole-body phosphor-autoradiography, fluorescence imaging and biodistribution were performed. Furthermore, ex vivo tumour TLR5 expression was proved through immunohistochemistry staining. We found that 125 I-anti-TLR5 mAb could bind to TLR5+ 4T1 with high affinity and specificity. Whole-body phosphor-autoradiography after 125 I-anti-TLR5 mAb injection showed TLR5+ 4T1 tumour images in 24 hours, more clearly in 48 hours. Radioactivities in tumour tissues were positively related with TLR5 expression. Biodistribution assay showed that 125 I-anti-TLR5 mAb was mainly metabolized through the liver and kidney, and 125 I-anti-TLR5 mAb was much more accumulated in TLR5+ 4T1 tumour than TLR5- 4T1. In vivo fluorescence imaging successfully showed tumour tissues clearly both in TLR5+ and TLR5- 4T1 mice compared with lentivirus untreated 4T1 tumour. Immunohistochemistry staining showed that TLR5 expression in tumours was indeed down-regulated in TLR5- 4T1 mice. Our results indicated that 125 I-antiTLR5 mAb was an ideal agent for non-invasive imaging of TLR5+ tumours; TLR5 may be as a novel molecular target for TNBC non-invasive diagnosis.

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.