Significant correlation of TLR4 expression with the clinicopathological features of invasive ductal carcinoma of the breast

Clinicopathological Significance and Prognostic Role of High Mobility Group Box 1 (HMGB1), Toll-Like Receptor (TLR) 2 and TLR4 in Breast Cancer

High-mobility group box 1 (HMGB1) functions as damage-associated molecular pattern (DAMPs), released into extracellular space during cellular stress. Extracellular HMGB1 act as signal molecules through Toll-like receptor (TLR) 2 or TLR4, exerting diverse functions in both normal cells and malignant cells including breast cancer. However, their comprehensive examination in breast cancer tissues is lacking. Thus, we immunolocalized them in 112 breast cancer tissues, correlating their immunoreactivity with clinicopathological parameters and clinical outcomes to clarify their significance in breast cancer. We demonstrated that nuclear HMGB1 immunoreactivity was correlated with tumor progression and longer disease-free survival. In contrast, TLR2 immunoreactivity was correlated with increased cell proliferation and shorter disease-free survival, dependent on cytoplasmic HMGB1 immunoreactivity. Additionally, TLR4 immunoreactivity correlated with chemoresistance, regardless of cytoplasmic HMGB1 immunoreactivity. It was therefore considered that TLR2 collaboratively contributed to breast cancer progression with HMGB1-DAMPs to become a worse prognostic factor. Meanwhile, TLR4 served as a worse prognostic factor associated with chemoresistance, irrespective of HMGB1.

Prognostic and clinicopathological significance of TLR4 expression in patients with breast cancer: a meta-analysis

Background

The prognostic value of Toll-like receptor 4 (TLR4) in breast cancer remains to be determined. Therefore, this paper aims to conduct a meta-analysis to assess the correlation between TLR4 and clinicopathological indicators as well as survival outcomes in breast cancer.

Method

Related literature retrieved from Embase, PubMed, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI) and China Wanfang. The search deadline is April 12, 2023. The outcome measures employed in the study comprised hazard ratio (HR), odds ratio (OR), and 95% confidence interval (CI) as effective indices. The data analysis was conducted using Stata 17.0 software.

Results

High TLR4 expression was associated with lymph node metastasis (OR=2.077, 95%CI=1.160-3.717, P= 0.014), tumor size (≥2 cm) (OR=2.194, 95%CI= 1.398-3.445, P= 0.001), PR expression (OR = 0.700, 95% CI = 0.505-0.971, P= 0.033), and clinical stage (OR = 3.578, 95%CI= 3.578-5.817, P<0.05), but not with histological grade (95%CI= 0.976-1.735, P= 0.072), ER expression (OR = 1.125, 95% CI = 0.492-2.571,P= 0.781), and HER-2 status (OR = 1.241, 95% CI = 0.733-2.101, P = 0.422). In addition, TLR4 overexpression was an independent prognostic indicator of DFS (HR= 1.480, 95%CI= 1.028- 2.130, p= 0.035) in breast cancer patients, but not related to OS(HR=1.730, 95%CI= 0.979-3.057, P= 0.059).

Conclusions

From our main analysis results, high TLR4 expression is associated with lymph node metastasis, larger tumor size (≥2 cm), later clinical stage, negative PR expression and shorter DFS, suggesting poor prognosis in breast cancer patients.

Prognostic Value of NLRP3 Inflammasome and TLR4 Expression in Breast Cancer Patients

Inflammasome complexes play a pivotal role in different cancer types. NOD-like receptor protein 3 (NLRP3) inflammasome is one of the most well-studied inflammasomes. Activation of the NLRP3 inflammasome induces abnormal secretion of soluble cytokines, generating advantageous inflammatory surroundings that support tumor growth. The expression levels of the NLRP3, PYCARD and TLR4 were determined by immunohistochemistry in a cohort of primary invasive breast carcinomas (BCs). We observed different NLRP3 and PYCARD expressions in non-tumor vs tumor areas (p<0.0001). All the proteins were associated to more aggressive clinicopathological characteristics (tumor size, grade, tumor proliferative activity etc.). Univariate analyses were carried out and related Kaplan-Meier curves plotted for NLRP3, PYCARD and TLR4 expression. Patients with higher NLRP3 and TLR4 expression had worse 5-year disease-free survival (DFS) compared to patients with lower NLRP3 and TLR4 expression (p =0.021 and p = 0.009, respectively). In multivariate analysis, TLR4 was confirmed as independent prognostic factors for DFS (HR = 2.03, 95% CI 1.16–3.57, p = 0.014), and high NLRP3 expression showed a slight association with DFS (HR = 1.75, 95% CI 0.98–3.15, p = 0.06). In conclusion, we showed TLR4 expression as independent prognostic factors and we highlighted for the first time that high expression of NLRP3 is linked to a poor prognosis in BC patients. These results suggest that NLRP3 and TLR4 could be two new good prognostic factor for BC patients.

The Natural Flavonoid Naringenin Inhibits the Cell Growth of Wilms Tumor in Children by Suppressing TLR4/NF-&#954;B Signaling

BACKGROUND

Nuclear Factor-kappa B (NF-κB) is usually activated in Wilms Tumor (WT) cells and plays a critical role in WT development.

OBJECTIVE

The study's purpose was to screen for a NF-κB inhibitor from the natural product library and explore its effects on WT development.

METHODS

Luciferase assay was employed to assess the effects of natural chemicals on NF-κB activity. CCK-8 assay was conducted to assess cell growth in response to naringenin. WT xenograft model was established to analyze the effect of naringenin in vivo. Quantitative real-time PCR and Western blot were performed to examine the mRNA and protein levels of relative genes, respectively.

RESULTS

Naringenin displayed a significant inhibitory effect on NF-κB activation in SK-NEP-1 cells. In SKNEP- 1 and G-401 cells, naringenin inhibited p65 phosphorylation. Moreover, naringenin suppressed TNF-α- induced p65 phosphorylation in WT cells. Naringenin inhibited TLR4 expression at both mRNA and protein levels in WT cells. CCK-8 staining showed that naringenin inhibited cell growth of the two above WT cells in doseand time-dependent manner, whereas Toll-Like Receptor 4 (TLR4) overexpression partially reversed the above phenomena. Besides, naringenin suppressed WT tumor growth in a dose- and time-dependent manner in vivo. Western blot found that naringenin inhibited TLR4 expression and p65 phosphorylation in WT xenograft tumors.

CONCLUSION

Naringenin inhibits WT development via suppressing TLR4/NF-κB signaling.

Interleukin-10: A double-edged sword in breast cancer

Breast cancer (BC) is a frequently diagnosed cancer among women worldwide. Currently, BC can be divided into different subgroups according to the presence of the following hormone receptors: estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Each of these subgroups has different treatment strategies. However, the presence of new metastatic lesions and patient deterioration suggest resistance to a given treatment. Various lines of evidence had shown that cytokines are one of the important mediators of tumor growth, invasion, metastasis, and treatment resistance. Interleukin-10 (IL-10) is an immunoregulatory cytokine, and acts as a poor prognostic marker in many cancers. The anti-inflammatory IL-10 blocks certain effects of inflammatory cytokines. It also antagonizes the co-stimulatory molecules on the antigen-presenting cells. Here, we review the current knowledge on the function and molecular mechanism of IL-10, and recent findings on how IL-10 contributes to the progression of BC.

NLRP3 Inflammasome From Bench to Bedside: New Perspectives for Triple Negative Breast Cancer

The tumor microenvironment (TME) is crucial in cancer onset, progression and response to treatment. It is characterized by an intricate interaction of immune cells and cytokines involved in tumor development. Among these, inflammasomes are oligomeric molecular platforms and play a key role in inflammatory response and immunity. Inflammasome activation is initiated upon triggering of pattern recognition receptors (Toll-like receptors, NOD-like receptors, and Absent in melanoma like receptors), on the surface of immune cells with the recruitment of caspase-1 by an adaptor apoptosis-associated speck-like protein. This structure leads to the activation of the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 and participates in different biological processes exerting its effects. To date, the Nod-Like Receptor Protein 3 (NLRP3) inflammasome has been well studied and its involvement has been established in different cancer diseases. In this review, we discuss the structure, biology and mechanisms of inflammasomes with a special focus on the specific role of NLRP3 in breast cancer (BC) and in the sub-group of triple negative BC. The NLRP3 inflammasome and its down-stream pathways could be considered novel potential tumor biomarkers and could open new frontiers in BC treatment.

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.

Risk of breast cancer in women with non-lactational mastitis

Little is known regarding the association of non-lactational mastitis women with breast cancer risk. This population-based cohort study examined the breast cancer risk in women with non-lactational mastitis. We identified 3,091 women with non-lactational mastitis between 2000 and 2011 using the Taiwan National Health Insurance Research Database. We performed 1:4 propensity score matching by age, socioeconomic status and comorbidities and identified 12,364 women without non-lactational mastitis. The mean age of women with non-lactational mastitis was 37.9 years; these women had a higher breast cancer risk than the comparison group (adjusted hazard ratio = 1.94, 95% confidence interval: 1.30–2.90). The incidence rates of breast cancer in women with non-lactational mastitis and the comparison group were 14.79 and 7.57 per 10,000 person-years, respectively. Furthermore, non-lactational mastitis was a risk factor for breast cancer in women aged <50 years, women with lower socioeconomic status and women with hormonal medication (p < 0.05). Women who had more episodes of non-lactational mastitis had a higher risk of developing a breast cancer. Thus, the risk of breast cancer in women with non-lactational mastitis is significantly higher than those without non-lactational mastitis.

Toll-like receptor 4 and breast cancer: an updated systematic review

Toll-like receptors (TLRs) may play dual roles in human cancers. TLR4 is a key molecule which may participate in both friend and foe roles against breast cancer. This review article collected recent data regarding the mechanisms used by TLR4 in the eradication of breast cancer cells and induction of the tumor cells, and discussed the mechanisms involved in the various functions of TLR4. The literature searches revealed that TLR4 is a key molecule that participates in breast cancer cell eradication or induction of breast cancer development and also transformation of the normal cells. TLR4 eradicates breast cancer cells via recognition of their DAMPs and then induces immune responses. Over-expression of TLR4 and also alterations in its signaling, including association of some intrinsic pathways such as TGF-β signaling and TP53, are the crucial factors to alter TLR4 functions against breast cancer.

Resistin facilitates breast cancer progression via TLR4-mediated induction of mesenchymal phenotypes and stemness properties

Growing evidence indicates that resistin-an obesity-related cytokine-is upregulated in breast cancer patients, yet its impact on breast cancer behavior remains to be ascertained. Similarly, Toll-like receptor 4 (TLR4) has been implicated in breast cancer progression, however, its clinically relevant endogenous ligand remains elusive. In this study, we observed that high serum resistin levels in breast cancer patients positively correlated with tumor stage, size and lymph node metastasis. These findings were replicated in animal models of breast cancer tumorigenesis and metastasis. Resistin was found to promote epithelial-mesenchymal transition and stemness in breast cancer cells-mechanisms critical to tumorigenesis and metastasis-through a TLR4/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)/signal transducer and activator of transcription 3 (STAT3) signaling pathway and negated by TLR4-specific antibody and antagonist. These findings provide clear evidence that resistin is a clinically relevant endogenous ligand for TLR4, which promotes tumor progression via TLR4/NF-κB/STAT3 signaling, providing insights into a novel therapeutic target in breast cancer.

Toll-like receptor 4 as a predictor of clinical outcomes of estrogen receptor-negative breast cancer in Saudi women

The aim of this study was to investigate the association of the common polymorphisms of Toll-like receptor 4 (TLR-4) with breast cancer development in the Saudi Arabian population. Four TLR-4 polymorphisms (rs2770150, rs10759931, rs10759932, and rs4986790) were studied using 127 breast cancer patients and 117 controls. Relative expression of TLR-4 protein in the breast tumor and the matched normal breast tissues was determined in a large cohort of 70 clinical breast samples in a tissue micro-array format by immunohistochemistry using a specific anti-TLR-4 antibody. Our results demonstrated an increase in TLR-4 expression in estrogen receptor (ER)−, postmenopausal breast cancer patients compared to normal. We also demonstrated that the G allele of single-nucleotide polymorphism rs10759931 was found to be significantly higher in frequency among patients (36.3%) compared to the control group (26.7%), suggesting that this polymorphism is strongly associated with the development of breast cancer in this ethnic population. In addition, the TLR-4 polymorphism rs2770150 was shown to be highly correlated with breast cancer in patients over 48 years of age. The TLR-4 polymorphism rs4986790 was also found to be associated with this malignancy in the ER− patient groups. Our results suggested firstly that the variation in TLR-4 gene expression may influence breast cancer development and secondly a closely linked association between TLR-4 gene polymorphism and ER status. Our study provides support for a better understanding of the implication of TLR-4 polymorphism in breast tumorigenesis and for its eventual use as a cancer biomarker.

Myeloid differentiation primary response gene 88-leukotriene B4 receptor 2 cascade mediates lipopolysaccharide-potentiated invasiveness of breast cancer cells

Inflammation and local inflammatory mediators are inextricably linked to tumor progression through complex pathways in the tumor microenvironment. Lipopolysaccharide (LPS) exposure to tumor cells has been suggested to promote tumor invasiveness and metastasis. However, the detailed signaling mechanism involved has not been elucidated. In this study, we showed that LPS upregulated the expression of leukotriene B₄ receptor-2 (BLT2) and the synthesis of BLT2 ligands in MDA-MB-231 and MDA-MB-435 breast cancer cells, thereby promoting invasiveness. BLT2 depletion with siRNA clearly attenuated LPS-induced invasiveness. In addition, we demonstrated that myeloid differentiation primary response gene 88 (MyD88) lies upstream of BLT2 in LPS-potentiated invasiveness and that this ‘MyD88-BLT2’ cascade mediates activation of NF-κB and the synthesis of IL-6 and IL-8, which are critical for the invasiveness and aggression of breast cancer cells. LPS-driven metastasis of MDA-MB-231 cells was also markedly suppressed by the inhibition of BLT2. Together, our results demonstrate, for the first time, that LPS potentiates the invasiveness and metastasis of breast cancer cells via a ‘MyD88-BLT2’-linked signaling cascade.

Toll-like receptor 4 prompts human breast cancer cells invasiveness via lipopolysaccharide stimulation and is overexpressed in patients with lymph node metastasis

Toll-like receptor (TLR)4-mediated signaling has been implicated in tumor cell invasion, survival, and metastasis in a variety of cancers. This study investigated the expression and biological role of TLR4 in human breast cancer metastasis. MCF-7 and MDA-MB-231 are human breast cancer cell lines with low and high metastatic potential, respectively. Using lipopolysaccharide (LPS) to stimulate MCF-7 and MDA-MB-231 cells, expression of TLR4 mRNA and protein increased compared with that in control cells. TLR4 activation notably up-regulated expression of matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor(VEGF) mRNA and their secretion in the supernatants of both cell lines. LPS enhanced invasion of MDA-MB-231 cells by transwell assay and MCF-7 cells by wound healing assay. LPS triggered increased expression of TLR4 downstream signaling pathway protein myeloid differentiation factor 88(MyD88) and resulted in interleukin (IL)-6 and IL-10 higher production by human breast cancer cells. Stimulation of TLR4 with LPS promoted tumorigenesis and formed metastatic lesions in liver of nude mice. Moreover, expression of TLR4 and MyD88 as well as invasiveness and migration of the cells could be blocked by TLR4 antagonist. Combined with clinicopathological parameters, TLR4 was overexpressed in human breast cancer tissue and correlated with lymph node metastasis. These findings indicated that TLR4 may participate in the progression and metastasis of human breast cancer and provide a new therapeutic target.

TLRs: linking inflammation and breast cancer

Breast cancer is one of the leading causes of mortality in the females. Intensive efforts have been made to understand the molecular mechanisms of pathogenesis of breast cancer. The physiological conditions that lead to tumorigenesis including breast cancer are not well understood. Toll like receptors (TLRs) are essential components of innate immune system that protect the host against bacterial and viral infection. The emerging evidences suggest that TLRs are activated through pathogen associated molecular patterns (PAMPs) as well as endogenous molecules, which lead to the activation of inflammatory pathways. This leads to increased levels of several pro-inflammatory cytokines and chemokines mounting inflammation. Several evidences support the view that chronic inflammation can lead to cancerous condition. Inflammation aids in tumor progression and metastasis. Association of inflammation with breast cancer is emerging. TLR mediated activation of NF-κB and IRF is an essential link connecting inflammation to cancer. The recent reports provide several evidences, which suggest the important role of TLRs in breast cancer pathogenesis and recurrence. The current review focuses on emerging studies suggesting the strong linkages of TLR mediated regulation of inflammation during breast cancer and its metastasis emphasizing the initiation of the systematic study.

Should a Toll-like receptor 4 (TLR-4) agonist or antagonist be designed to treat cancer? TLR-4: its expression and effects in the ten most common cancers

Toll-like receptor 4 (TLR-4) is well known for its host innate immunity. Despite the fact that TLR-4 activation confers antitumor responses; emerging evidence suggests that TLR-4 is associated with tumor development and progression. It is now clear that overactivation of TLR-4, through various immune mediators, may cause immune response dysfunction, resulting in tumorigenesis. Different cancers could have different extents of TLR-4 involvement during tumorigenesis or tumor progression. In this review, we focus on infection- and inflammation-related TLR-4 activation in noncancer and cancer cells, as well as on the current evidence about the role of TLR-4 in ten of the most common cancers, viz, head and neck cancer, lung cancer, gastrointestinal cancer, liver cancer, pancreatic cancer, skin cancer, breast cancer, ovarian cancer, cervical cancer, and prostate cancer.

Mutations in components of antiviral or microbial defense as a basis for breast cancer

In-depth functional analyses of thousands of breast cancer gene mutations reveals vastly different sets of mutated genes in each of 21 different breast cancer genomes. Despite differences in which genes are mutated, innate immunity pathways and metabolic reactions supporting them are always damaged. These functions depend on many different genes. Mutations may be rare individually but each set of mutations affects some aspect of pathogen recognition and defense, especially those involving viruses. Some mutations cause a dysregulated immune response, which can also increase cancer risks. The frequency of an individual mutation may be less important than its effect on function. This work demonstrates that acquired immune deficiencies and immune dysregulation in cancer can occur because of mutations. Abnormal immune responses represent a hidden variable in breast cancer-viral association studies. Compensating for these abnormalities may open many new opportunities for cancer prevention and therapy.

Trial Watch: Toll-like receptor agonists for cancer therapy

Toll-like receptors (TLRs) have long been known for their ability to initiate innate immune responses upon exposure to conserved microbial components such as lipopolysaccharide (LPS) and double-stranded RNA. More recently, this family of pattern recognition receptors has been attributed a critical role in the elicitation of anticancer immune responses, raising interest in the development of immunochemotherapeutic regimens based on natural or synthetic TLR agonists. In spite of such an intense wave of preclinical and clinical investigation, only three TLR agonists are currently licensed by FDA for use in cancer patients: bacillus Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis that operates as a mixed TLR2/TLR4 agonist; monophosphoryl lipid A (MPL), a derivative of Salmonella minnesota that functions as a potent agonist of TLR4; and imiquimod, a synthetic imidazoquinoline that activates TLR7. One year ago, in the August and September issues of OncoImmunology, we described the main biological features of TLRs and discussed the progress of clinical studies evaluating the safety and therapeutic potential of TLR agonists in cancer patients. Here, we summarize the latest developments in this exciting area of research, focusing on preclinical studies that have been published during the last 13 mo and clinical trials launched in the same period to investigate the antineoplastic activity of TLR agonists.