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

Exploring the modulation of TLR4 and its associated ncRNAs in cancer immunopathogenesis, with an emphasis on the therapeutic implications and mechanisms underlying drug resistance

This study provides an in-depth analysis of the pathogenic relevance, therapeutic implications, and mechanisms of treatment resistance associated with TLR4 and its ncRNAs in cancer immunopathogenesis. TLR4, a pivotal component of the innate immune response, has been implicated in promoting inflammation, tumorigenesis, and immune evasion across various malignancies, including gastric, ovarian, and hepatocellular carcinoma. The interactions between TLR4 and specific ncRNAs, such as lncRNAs and miRNAs, play a crucial role in modulating TLR4 signaling pathways, influencing immune cell dynamics, and contributing to chemoresistance. These ncRNAs facilitate tumor-promoting processes, including macrophage polarization, dendritic cell suppression, and T-cell regulation, effectively establishing an immunosuppressive tumor microenvironment that further enhances therapeutic resistance. A comprehensive understanding of the complex interplay between TLR4 and ncRNAs unveils potential avenues for identifying predictive biomarkers and discovering novel therapeutic targets in cancer. Future research initiatives should prioritize the development of personalized therapeutic strategies that specifically target TLR4 signaling and its ncRNA regulators to counteract drug resistance and improve clinical outcomes. This review extensively evaluates the role of TLR4 in cancer biology, emphasizing its critical importance in developing innovative cancer management strategies.

ALDHHigh Breast Cancer Stem Cells Exhibit a Mesenchymal-Senescent Hybrid Phenotype, with Elevated Metabolic and Migratory Activities

Cancer stem cells (CSCs) account for 0.01 to 2% of the total tumor mass; however, they play a key role in tumor progression, metastasis and resistance to current cancer therapies. The generation and maintenance of CSCs are usually linked to the epithelial-mesenchymal transition (EMT), a dynamic process involved in reprogramming cancer cells towards a more aggressive and motile phenotype with increased stemness potential. Cells that undergo an EMT process have shown to be more resistant to conventional chemo/radiotherapies. In this context, aldehyde dehydrogenase (ALDH) enzymes, known for their role in the cellular detoxification of aldehydes and enhancement of cell survival, are often upregulated in cancer cells, promoting their resistance to conventional cancer treatments. Indeed, high ALDH levels have become a hallmark biomarker of CSCs and are often used to isolate this sub-population from the more abundant cancer cell populations. Herein, we isolated human breast cancer epithelial cells with higher ALDH abundance (ALDHHigh) and compared them to those with low ALDH abundance (ALDHLow). ALDHHigh sub-populations exhibited more characteristic EMT biomarkers by adopting a more mesenchymal phenotype with increased stemness and enhanced migratory potential. Furthermore, ALDHHigh sub-populations displayed elevated senescent markers. Moreover, these cells also demonstrated higher levels of mitochondria DNA/mass, as well as greater mitochondrial and glycolytic metabolic function. Conversely, ALDHLow sub-populations showed a higher efficiency of mammosphere/colony formation and an increased proliferative capacity. Therefore, we demonstrated that these ALDH sub-populations have distinct characteristics, underscoring their role in EMT, the formation of tumors and the mechanisms of metastasis.

Detoxified pneumolysin derivative ΔA146Ply inhibits triple- negative breast cancer metastasis mainly via mannose receptor-mediated autophagy inhibition

The detoxified pneumolysin derivative ΔA146Ply has been proven to have a direct anti-triple negative breast cancer effect by our group, but its work model remains unclear. In this study, we focused on its ability to inhibit triple-negative breast cancer metastasis. We found that ΔA146Ply suppressed the migration and invasion of triple-negative breast cancer cells by activating mannose receptor and toll-like receptor 4. Their activation triggers the activation of the mammalian target of rapamycin signalling, sequentially leading to autophagy, transforming growth factor-β1, and epithelial-mesenchymal transition inhibition. Furthermore, the combination of doxorubicin and ΔA146Ply significantly inhibited triple-negative breast cancer progression and prolonged survival in tumour-bearing mice. Taken together, our study provides an alternative microbiome-based mannose receptor-targeted therapy for triple-negative breast cancer and a novel theoretical and experimental basis for the downstream signalling pathway of the mannose receptor.

Multi-Drug Resistance and Breast Cancer Progression via Toll-Like Receptors (TLRs) Signaling

Toll-like receptors (TLRs) are essential receptors involved in inflammation and innate immunity. Various types of cancer cells, as well as innate immune cells, express TLRs. There is mounting proof that TLRs are critical to the development and spread of cancer as well as metabolism. In breast cancer, up-regulated levels of TLRs have been linked to the aggressiveness of the diseases, worse treatment outcomes, and the emergence of therapeutic resistance. Patients with advanced non-resectable, recurring, and metastatic breast cancer currently have few available treatment choices. An intriguing new strategy is an innate immunity-mediated anticancer immunotherapy, either used alone or in conjunction with existing treatments. In fact, several TLR agonists and antagonists have been used in clinical studies for anti-cancer immunotherapy. Consequently, TLRs serve as critical targets for controlling the course of breast cancer and treatment resistance in addition to being implicated in immune responses against pathogen infection and cancer immunology. In this review, we deliver an overview of the most current findings on TLR involvement in the development of breast cancer and treatment resistance.

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.

Multiple Factors Determine the Oncolytic or Carcinogenic Effects of TLRs Activation in Cancer

Toll‐like receptors (TLRs) belong to a germline‐encoded protein family. These are pattern recognition receptors. They sense pathogen‐associated molecular patterns (PAMPs). When this occurs, activation of the NF‐ĸB pathway follows. This triggers the innate immune response of the host. The consequent inflammatory cytokine response usually contributes to the elimination of the pathogen. Activation of TLRs also induces an adaptive immune response by a cross‐prime mechanism. This mechanism is employed in cancer immunotherapy. Using TLR ligands as adjuvants induces upregulation of costimulatory signals which in turn activates a cytotoxic leukocyte response against cancer cells. However, TLRs are also overexpressed in human cancer cells resulting in increased cell proliferation, migration, invasion, and angiogenesis. An intracellular adaptor, myeloid differentiation factor 88 (MyD88) probably mediates this process. MyD88 is intimately involved with all TLRs except TLR3. One consequence of the interaction between a TLR and MyD88 is activation of NF‐ĸB. In this context of a variety of proinflammtory cytokines being produced, chronic inflammation may result. Inflammation is an important protective mechanism. However, chronic inflammation is also involved in carcinogenesis. Activation of NF‐ĸB inhibits apoptosis and under certain circumstances, tumor cell survival. In this review, the potential therapeutic value of TLRs in immunotherapy and its role in oncogenesis are explored. The emerging use of artificial intelligence is mentioned.

AUTOSURV: INTERPRETABLE DEEP LEARNING FRAMEWORK FOR CANCER SURVIVAL ANALYSIS INCORPORATING CLINICAL AND MULTI-OMICS DATA

Accurate prognosis for cancer patients can provide critical information for optimizing treatment plans and improving life quality. Combining omics data and demographic/clinical information can offer a more comprehensive view of cancer prognosis than using omics or clinical data alone and can reveal the underlying disease mechanisms at the molecular level. In this study, we developed a novel deep learning framework to extract information from high-dimensional gene expression and miRNA expression data and conduct prognosis prediction for breast cancer and ovarian cancer patients. Our model achieved significantly better prognosis prediction than the conventional Cox Proportional Hazard model and other competitive deep learning approaches in various settings. Moreover, an interpretation approach was applied to tackle the "black-box" nature of deep neural networks and we identified features (i.e., genes, miRNA, demographic/clinical variables) that made important contributions to distinguishing predicted high- and low-risk patients. The identified associations were partially supported by previous studies.

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).

Associations Between Serum Soluble Toll-like Receptors 4 and 9 and Breast Cancer in Egyptian Patients

BACKGROUND

Toll-like receptors (TLRs) play an important role in regulation of immune cells and are vital in tumorigenesis due to its crucial role in inflammatory microenvironment regulation, as they promote the synthesis and release of inflammatory cytokines and chemokines. Toll-like receptors 4 and TLRs 9 were found to be highly expressed in breast cancer. The aim of this study is to investigate the soluble toll-like receptors 4 and 9 (sTLR4 and sTLR9) as potential biomarkers for diagnosis and prognosis of breast cancer and their association with the clinicopathological parameters of breast cancer.

PATIENTS AND METHOD

In this retrospective case-control study, 186 female subjects were recruited and divided into three groups, Group I: 62 healthy control, Group II: 62 subjects diagnosed with non-metastatic breast cancer, and Group III: 62 subjects diagnosed with metastatic breast cancer. Enzyme-linked immunosorbent assay (ELISA) technique was used to quantify the levels of sTLR4 and sTLR9 in serum.

RESULTS

Both non-metastatic and metastatic groups showed significant higher levels of both serum sTLR4 and sTLR9 expression compared to healthy controls. Only sTLR9 was significantly increased among metastatic patients compared to non-metastatic group. Serum levels of sTLR9 and sTLR4 were still significantly associated with breast cancer in a multiple logistic regression model (P = <.001). ROC curves showed that both sTLR4 and sTLR9 can be a significant parameter to discriminate between normal females and breast cancer patients.

CONCLUSION

Soluble toll-like receptors 4 and sTLR9 are over-expressed in patients with metastatic and non-metastatic BC than in benign cases. The expression levels of sTLR4 and TLR9 have clinical interest as indicators of tumor aggressiveness suggested to be prognostic biomarkers. Toll-like receptors may represent therapeutic targets in breast cancer.

Molecular Characterization of CF33 Canine Cell Line and Evaluation of Its Ability to Respond against Infective Stressors in Sight of Anticancer Approaches

Simple Summary

Canine mammary cancer is very common and has many similarities with human breast cancer. Risk factors, physiological and pathological behaviors, and the clinical course in dogs are very similar to humans. Several molecular similarities have also been reported, such as overexpression of EGF, proliferation markers, metalloproteinase and cyclooxygenase, TP53 mutations, and CXCR4/SDF1 axis activation. These common characteristics make these breast tumors resistant to conventional therapies. It is therefore necessary to study therapeutic alternatives. Cell lines could be helpful to test in vitro immunomodulant anti-cancer therapies, allowing a reduction of laboratory animals’ involvement in the preliminary tests and achieving results in a shorter time. Although the canine mammary carcinoma cell line CF33 has been widely used in many studies on dog mammary cancer, characterization of its gene expression profile and of the influence of infective stressors of this cell line is poor. Our study shows the interaction of CF33 and Salmonella Typhimurium (ST) as an infective stressor, indicating that these cells may represent an in vitro model for assessing novel therapeutic approaches using bacteria.

Abstract

Spontaneous mammary tumors are the most frequent neoplasms in bitches and show similarities with human breast cancer in risk factors, clinical course, and histopathology. The poor prognosis of some cancer subtypes, both in human and dog, demands more effective therapeutic approaches. A possible strategy is the new anticancer therapy based on immune response modulation through bacteria or their derivatives on canine mammary carcinoma cell lines. The aim of the present study was to analyze the CF33 cell line in terms of basal expression of immune innate genes, CXCR4 expression, and interaction with infectious stressors. Our results highlight that CF33 maintains gene expression parameters typical of mammary cancer, and provides the basal gene expression of CF33, which is characterized by overexpression of CXCR4, CD44, RAD51, LY96, and a non-continuous expression of TP53 and PTEN. No mutations appeared in the CXCR4 gene until the 58th passage; this may represent important information for studying the CXCR4 pathway as a therapeutic target. Moreover, the CF33 cell line was shown to be able to interact with Salmonella Typhimurium (ST) (an infective stressor), indicating that these cells could be used as an in vitro model for developing innovative therapeutic approaches involving bacteria.

Molecular and Cellular Mechanisms of Propolis and Its Polyphenolic Compounds against Cancer

In recent years, interest in natural products such as alternative sources of pharmaceuticals for numerous chronic diseases, including tumors, has been renewed. Propolis, a natural product collected by honeybees, and polyphenolic/flavonoid propolis-related components modulate all steps of the cancer progression process. Anticancer activity of propolis and its compounds relies on various mechanisms: cell-cycle arrest and attenuation of cancer cells proliferation, reduction in the number of cancer stem cells, induction of apoptosis, modulation of oncogene signaling pathways, inhibition of matrix metalloproteinases, prevention of metastasis, anti-angiogenesis, anti-inflammatory effects accompanied by the modulation of the tumor microenvironment (by modifying macrophage activation and polarization), epigenetic regulation, antiviral and bactericidal activities, modulation of gut microbiota, and attenuation of chemotherapy-induced deleterious side effects. Ingredients from propolis also "sensitize" cancer cells to chemotherapeutic agents, likely by blocking the activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In this review, we summarize the current knowledge related to the the effects of flavonoids and other polyphenolic compounds from propolis on tumor growth and metastasizing ability, and discuss possible molecular and cellular mechanisms involved in the modulation of inflammatory pathways and cellular processes that affect survival, proliferation, invasion, angiogenesis, and metastasis of the tumor.

Interaction of Opioids with TLR4-Mechanisms and Ramifications

Simple Summary

Recent evidence indicates that opioids can be active at a receptor that is abundantly expressed on innate immune cells as well as cancer cells: the receptor is termed toll-like receptor 4 (TLR4). TLR4 is increasingly recognised as playing key roles in tumour biology and anticancer defences. However, the issue of whether TLR4 mediates some of the effects of opioids on tumour growth and metastasis is entirely unknown. We review existing evidence, mechanisms, and functional consequences of the action of opioids at TLR4. This opens new avenues of research on the role of opioids in cancer.

Abstract

The innate immune receptor toll-like receptor 4 (TLR4) is known as a sensor for the gram-negative bacterial cell wall component lipopolysaccharide (LPS). TLR4 activation leads to a strong pro-inflammatory response in macrophages; however, it is also recognised to play a key role in cancer. Recent studies of the opioid receptor (OR)-independent actions of opioids have identified that TLR4 can respond to opioids. Opioids are reported to weakly activate TLR4, but to significantly inhibit LPS-induced TLR4 activation. The action of opioids at TLR4 is suggested to be non-stereoselective, this is because OR-inactive (+)-isomers of opioids have been shown to activate or to inhibit TLR4 signalling, although there is some controversy in the literature. While some opioids can bind to the lipopolysaccharide (LPS)-binding cleft of the Myeloid Differentiation factor 2 (MD-2) co-receptor, pharmacological characterisation of the inhibition of opioids on LPS activation of TLR4 indicates a noncompetitive mechanism. In addition to a direct interaction at the receptor, opioids affect NF-κB activation downstream of both TLR4 and opioid receptors and modulate TLR4 expression, leading to a range of in vivo outcomes. Here, we review the literature reporting the activity of opioids at TLR4, its proposed mechanism(s), and the complex functional consequences of this interaction.

Suppression of MD2 inhibits breast cancer in vitro and in vivo

PURPOSE

To explore the effects of the intervening measure targeting myeloid differentiation 2 (MD2) on breast cancer progression in vitro and in vivo.

METHODS

The expression of MD2 in normal breast cells (Hs 578Bst) and three kinds of breast carcinoma cell lines (MCF-7, MDA-MB-231 s and 4T1) were detected by western blot. MTT assay was used to detect the proliferation of 4T1 cells treated by L6H21, cell migration and invasion was measured by wound healing assay and trans-well matrigel invasion assay, respectively. In addition, to further study the role of MD2 in tumor progression, we assessed the effects of inhibition of MD2 on the progression of xenograft tumors in vivo.

RESULTS

The expression of MD2 is much higher in MDA-MB-231 s and 4T1cells than that in normal breast cells (Hs 578Bst) or MCF-7 cells (p < 0.05). In vitro, suppression of MD2 by L6H21 has a significant inhibition of proliferation, migration and invasion in 4T1 cells in dose-dependent manner. In vivo, L6H21 pretreatment significantly improved survival of 4T1-bearing mice (p < 0.05). Additionally, we also observed that none of the mice died from the toxic effect of 10 mg kg-1 L6H21 in 60 days.

CONCLUSION

Overall, this work indicates that suppression of MD2 shows progression inhibition in vitro and significantly prolong survival in vivo. These findings provide the potential experimental evidence for using MD2 as a therapeutic target of breast carcinoma.

Atractylenolide-I Suppresses Tumorigenesis of Breast Cancer by Inhibiting Toll-Like Receptor 4-Mediated Nuclear Factor-κB Signaling Pathway

Background: Toll-like receptor 4 (TLR4) is an essential sensor related to tumorigenesis, and overexpression of TLR4 in human tumors often correlates with poor prognosis. Atractylenolide-I (AT-I), a novel TLR4-antagonizing agent, is a major bioactive component from Rhizoma Atractylodes Macrocephalae. Emerging evidence suggests that AT-I exerts anti-tumor effects on various cancers such as colorectal cancer, bladder cancer and melanoma. Nevertheless, the effects of AT-I on mammary tumorigenesis remain unclear. Methods: In order to ascertain the correlation of TLR4/NF-κB pathway with breast cancer, the expression of TLR4 and NF-κB in normal breast tissues and cancer tissues with different TNM-stages was detected by human tissue microarray and immunohistochemistry technology. The effects of AT-I on tumorigenesis were investigated by cell viability, colony formation, apoptosis, migration and invasion assays in two breast cancer cells (MCF-7 and MDA-MB-231), and N-Nitroso-N-methylurea induced rat breast cancer models were developed to evaluate the anti-tumor effects of AT-I in vivo. The possible underlying mechanisms were further explored by western blot and ELISA assays after a series of LPS treatment and TLR4 knockdown experiments. Results: We found that TLR4 and NF-κB were significantly up-regulated in breast cancer tissues, and was correlated with advanced TNM-stages. AT-I could inhibit TLR4 mediated NF-κB signaling pathway and decrease NF-κB-regulated cytokines in breast cancer cells, thus inhibiting cell proliferation, migration and invasion, and inducing apoptosis of breast cancer cells. Furthermore, AT-I could inhibit N-Nitroso-N-methylurea-induced rat mammary tumor progression through TLR4/NF-κB pathway. Conclusion: Our findings demonstrated that TLR4 and NF-κB were over expressed in breast cancer, and AT-I could suppress tumorigenesis of breast cancer via inhibiting TLR4-mediated NF-κB signaling pathway.

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.

Personalized analysis of breast cancer using sample-specific networks

Breast cancer is a disease with high heterogeneity. Cancer is not usually caused by a single gene, but by multiple genes and their interactions with others and surroundings. Estimating breast cancer-specific gene–gene interaction networks is critical to elucidate the mechanisms of breast cancer from a biological network perspective. In this study, sample-specific gene–gene interaction networks of breast cancer samples were established by using a sample-specific network analysis method based on gene expression profiles. Then, gene–gene interaction networks and pathways related to breast cancer and its subtypes and stages were further identified. The similarity and difference among these subtype-related (and stage-related) networks and pathways were studied, which showed highly specific for subtype Basal-like and Stages IV and V. Finally, gene pairwise interactions associated with breast cancer prognosis were identified by a Cox proportional hazards regression model, and a risk prediction model based on the gene pairs was established, which also performed very well on an independent validation data set. This work will help us to better understand the mechanism underlying the occurrence of breast cancer from the sample-specific network perspective.

TLR4: An Important Molecule Participating in Either Anti-Human Papillomavirus Immune Responses or Development of Its Related Cancers

It has been reported that human papillomavirus (HPV) is a main cause of cervical cancer. Immune system plays key roles in the HPV infection clearance. Additionally, the roles played by immune responses in development of cancers have been documented previously. Toll-like receptors (TLRs) are the main surface or intravesicular receptors driving innate immunity, which either participate in the fight against infectious agents or participate in the progression of cancers. Thus, it has been hypothesized that the molecules may be part of the HPV/cancers puzzle. TLR4 is a unique member of TLRs family that uses both well-known TLRs related intracellular signaling pathways. Furthermore, the roles played by TLR4 against several viruses and also their related complications, such as tumors, have been demonstrated. Thus, it has been hypothesized that TLR4 may play a key role in HPV infection and its related complications. This review article collected the information regarding the mentioned plausible roles by TLR4.

B7-H3 is regulated by BRD4 and promotes TLR4 expression in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies worldwide. PDAC is resistant to chemotherapy and radiotherapy which leads to the poor prognosis of PDAC patients and a 5-year survival rate of less than 5%. Exploring the mechanism of the pancreatic cancer tumorigenesis is the key to finding a novel therapeutic strategy for cancer treatment. B7-H3 belongs to the B7 family of immunoregulatory proteins, and the overexpression of B7-H3 is found in various types of cancer. The regulation of B7-H3 expression in pancreatic cancer is still unclear. Here, we showed that B7-H3 acted as a negative prognostic biomarker in PDAC and promoted cell proliferation, invasion and metastasis in pancreatic cancer. Next, we applied the drug screening method to identify bromodomain and extra-terminal motif (BET) inhibitors that decreased the protein and mRNA levels of B7-H3 in pancreatic cancer cells. Moreover, we verified that BRD4 was responsible for regulating the expression of B7-H3 at the transcriptional level. Finally, our data indicated that the BRD4/B7-H3 axis modulated the expression of TLR4 in pancreatic cancer cells. Taken together, our results elucidated the regulation of B7-H3 expression in pancreatic cancer and uncovered the importance of BRD4/B7-H3/TLR4 pathway. The targeting of B7-H3 by the BET inhibitors may be a novel therapeutic strategy to overcome the immunotherapy and chemotherapy resistance in pancreatic cancer.