Systemic neutralization of IL-17A significantly reduces breast cancer associated metastasis in arthritic mice by reducing CXCL12/SDF-1 expression in the metastatic niches

IL-17A-induced cancer-associated fibroblasts releases CXCL12 to promote lung adenocarcinoma progression via Wnt/β-Catenin signaling pathway

BACKGROUND

Cancer-associated fibroblasts (CAFs) and their secretion, C-X-C motif chemokine ligand 12 (CXCL12), play an important role in the development of lung adenocarcinoma (LUAD). Interleukin 17A (IL-17A) is also crucial in regulating tumor progression. Herein, we explored the specific relationships between these two factors and their mechanisms in the progression of LUAD.

METHODS

Immunohistochemistry was utilized to assess the differential expression levels of IL-17A and CXCL12 in tumor versus normal tissues of LUAD patients, followed by gene correlation analysis. Cell counting kit-8 (CCK8), wound-healing and transwell assays were performed to investigate the effect of IL-17A on the function of LUAD cells. qPCR, immunofluorescence, immunohistochemistry and western blot analyses were conducted to elucidate the potential mechanism by which IL-17A facilitates the development of LUAD via CXCL12. Male BALB-C nude mice were used to explore the role of IL-17A in subcutaneous LUAD mouse models.

RESULTS

Elevated expression levels of IL-17A and CXCL12 were observed in LUAD tissues, exhibiting a positive correlation. Further studies revealed that IL-17A could stimulate CAFs to enhance the release of CXCL12, thereby facilitating the growth, proliferation, and metastasis of LUAD. The binding of CXCL12 to its specific receptor influences the activation of the Wnt/β-Catenin pathway, which in turn affects the progression of LUAD. In vivo experiments have demonstrated that IL-17A enhances the growth of LUAD tumors by facilitating the secretion of CXCL12. Conversely, inhibiting CXCL12 has been demonstrated to impede tumor growth.

CONCLUSIONS

We discovered that IL-17A promotes the release of CAFs-derived CXCL12, which in turn facilitates the development of LUAD via the Wnt/β-Catenin signaling pathway.

Combining TIGIT Blockade with MDSC Inhibition Hinders Breast Cancer Bone Metastasis by Activating Antitumor Immunity

Bone is the most common site of breast cancer metastasis. Bone metastasis is incurable and is associated with severe morbidity. Utilizing an immunocompetent mouse model of spontaneous breast cancer bone metastasis, we profiled the immune transcriptome of bone metastatic lesions and peripheral bone marrow at distinct metastatic stages, revealing dynamic changes during the metastatic process. We show that cross-talk between granulocytes and T cells is central to shaping an immunosuppressive microenvironment. Specifically, we identified the PD-1 and TIGIT signaling axes and the proinflammatory cytokine IL1β as central players in the interactions between granulocytes and T cells. Targeting these pathways in vivo resulted in attenuated bone metastasis and improved survival, by reactivating antitumor immunity. Analysis of patient samples revealed that TIGIT and IL1β are prominent in human bone metastasis. Our findings suggest that cotargeting immunosuppressive granulocytes and dysfunctional T cells may be a promising novel therapeutic strategy to inhibit bone metastasis. Significance: Temporal transcriptome profiling of the immune microenvironment in breast cancer bone metastasis revealed key communication pathways between dysfunctional T cells and myeloid derived suppressor cells. Cotargeting of TIGIT and IL1β inhibited bone metastasis and improved survival. Validation in patient data implicated these targets as a novel promising approach to treat human bone metastasis.

Gut colonization with an obesity-associated enteropathogenic microbe modulates the premetastatic niches to promote breast cancer lung and liver metastasis

Introduction

Obesity, an independent risk factor for breast cancer growth and metastatic progression, is also closely intertwined with gut dysbiosis; and both obese state and dysbiosis promote each other. Enteric abundance of Bacteroides fragilis is strongly linked with obesity, and we recently discovered the presence of B. fragilis in malignant breast cancer. Given that enterotoxigenic B. fragilis or ETBF, which secretes B. fragilis toxin (BFT), has been identified as a procarcinogenic microbe in breast cancer, it is necessary to examine its impact on distant metastasis and underlying systemic and localized alterations promoting metastatic progression of breast cancer.

Methods

We used syngeneic mammary intraductal (MIND) model harboring gut colonization with ETBF to query distant metastasis of breast cancer cells. Alterations in the immune network and cytokines/chemokines in the tumor microenvironment and distant metastatic sites were examined using flow cytometry, immunohistochemistry, and multiplex arrays.

Results

ETBF infection initiates a systemic inflammation aiding in the establishment of the premetastatic niche formation in vital organs via increased proinflammatory and protumorigenic cytokines like IL17A, IL17E, IL27p28, IL17A/F, IL6, and IL10 in addition to creating a prometastatic immunosuppressive environment in the liver and lungs rich in myeloid cells, macrophages, and T regulatory cells. It induces remodeling of the tumor microenvironment via immune cell and stroma infiltration, increased vasculogenesis, and an EMT-like response, thereby encouraging early metastatic dissemination ready to colonize the conducive environment in liver and lungs of the breast tumor-bearing mice.

Discussion

In this study, we show that enteric ETBF infection concomitantly induces systemic inflammation, reshapes the tumor immune microenvironment, and creates conducive metastatic niches to potentiate early dissemination and seeding of metastases to liver and lung tissues in agreement with the "seed and soil hypothesis." Our results also support the ETBF-induced "parallel model" of metastasis that advocates for an early dissemination of tumor cells that form metastatic lesions independent of the primary tumor load.

Interleukin 17 in early invasive breast cancer

Introduction

Interleukin 17 (IL-17) has a key role in inflammatory responses. Increased serum concentrations of IL-17 have been reported in patients with different types of cancer. Some studies suggest antitumor activity of IL-17 while others speak in favor of its association with poorer prognosis. The lack of data on IL-17 behavior in vivo hinders the efforts to clarify the exact role of IL-17 in breast cancer patients and precludes the usage of IL-17 as potential therapeutic target.

Methods

The study included 118 patients with early invasive breast cancer. The serum concentration of IL-17A was measured before surgery and during adjuvant treatment and compared with healthy controls. The correlation of serum IL-17A concentration and different clinical and pathological parameters, including IL-17A expression in the corresponding tumor tissue samples, was analyzed.

Results

Significantly higher serum concentrations of IL-17A were found in women with early breast cancer before surgery, but also during adjuvant treatment in comparison to healthy controls. No significant correlation to tumor tissue IL-17A expression was observed. There was a significant postoperative decrease of serum IL-17A concentrations even in patients with relatively lower preoperative values. A significant negative correlation was found between serum IL-17A concentrations and the tumor estrogen receptor expression.

Conclusion

The results suggest that the immune response in early breast cancer is mediated by IL-17A, particularly in triple-negative breast cancer. IL-17A-mediated inflammatory response subsides postoperatively, but IL-17A concentrations remain elevated compared to the values in healthy controls, even after the removal of the tumor.

The role of Th-17 cells and IL-17 in the metastatic spread of breast cancer: As a means of prognosis and therapeutic target

Metastatic breast cancer is one of the most common and well-known causes of death for women worldwide. The inflammatory tumor cell and other cancer hallmarks dictate the metastatic form and dissemination of breast cancer. Taking these into account, from various components of the tumor microenvironment, a pro-inflammatory infiltrative cell known as Th-17 plays an immense role in breast cancer proliferation, invasiveness, and metastasis. It has been demonstrated that IL-17, a pleiotropic pro-inflammatory cytokine generated by Th-17, is upregulated in a metastatic form of breast cancer. Recent research updates stated that chronic inflammation and mediators like cytokines and chemokines are causative hallmarks in many human cancers, including breast cancer. Therefore, IL-17 and its multiple downward signaling molecules are the centers of research attention to develop potent treatment options for cancer. They provide information on the role of IL-17-activated MAPK, which results in tumor cell proliferation and metastasis via NF-kB-mediated expression of MMP signaling. Overall, this review article emphasizes IL-17A and its intermediate signaling molecules, such as ERK1/2, NF-kB, MMPs, and VEGF, as potential molecular targets for the prevention and treatment of breast cancer.

Anterior Gradient 2 is a Significant Prognostic Biomarker in Bone Metastasis of Breast Cancer

Background: The study aimed to detect DEGs associated with BRCA bone metastasis, filter prognosis biomarkers, and explore possible pathways.

Methods: GSE175692 dataset was used to detect DEGs between BRCA bone metastatic cases and non-bone metastatic cases, followed by the construction of a PPI network among DEGs. The main module among the PPI network was then determined and pathway analysis on genes within the module was performed. Through performing Cox regression, Kaplan-Meier, nomogram, and ROC curve analyses using GSE175692 and GSE124647 datasets at the same time, the most significant prognostic biomarker was gradually filtered. Finally, important pathways associated with prognostic biomarkers were explored by GSEA analysis.

Results: The 74 DEGs were detected between bone metastasis and non-bone metastasis groups. A total of 15 nodes were included in the main module among the whole PPI network and they mainly correlated with the IL-17 signaling pathway. We then performed Cox analysis on 15 genes using two datasets and only enrolled the genes with p < 0.05 in Cox analysis into the further analyses. Kaplan-Meier analyses using two datasets showed that the common biomarker AGR2 expression was related to the survival time of BRCA metastatic cases. Further, the nomogram determined the greatest contribution of AGR2 on the survival probability and the ROC curve revealed its optimal prognostic performance. More importantly, high expression of AGR2 prolonged the survival time of BRCA bone metastatic patients. These results all suggested the importance of AGR2 in metastatic BRCA. Finally, we performed the GSEA analysis and found that AGR2 was negatively related to IL-17 and NF-kβ signaling pathways.

Conclusion: AGR2 was finally determined as the most important prognostic biomarker in BRCA bone metastasis, and it may play a vital role in cancer progression by regulating IL-17 and NF-kB signaling pathways.

RUNX2 recruits the NuRD(MTA1)/CRL4B complex to promote breast cancer progression and bone metastasis

Runt-related transcription factor 2 (RUNX2) is an osteogenesis-related transcription factor that has emerged as a prominent transcription repressing factor in carcinogenesis. However, the role of RUNX2 in breast cancer metastasis remains poorly understood. Here, we show that RUNX2 recruits the metastasis-associated 1 (MTA1)/NuRD and the Cullin 4B (CUL4B)-Ring E3 ligase (CRL4B) complex to form a transcriptional-repressive complex, which catalyzes the histone deacetylation and ubiquitylation. Genome-wide analysis of the RUNX2/NuRD(MTA1)/CRL4B complex targets identified a cohort of genes including peroxisome proliferator-activated receptor alpha (PPARα) and superoxide dismutase 2 (SOD2), which are critically involved in cell growth, epithelial-to-mesenchymal transition (EMT) and invasion. We demonstrate that the RUNX2/NuRD(MTA1)/CRL4B complex promotes the proliferation, invasion, tumorigenesis, bone metastasis, cancer stemness of breast cancer in vitro and in vivo. Strikingly, RUNX2 expression is upregulated in multiple human carcinomas, including breast cancer. Our study suggests that RUNX2 is a promising potential target for the future treatment strategies of breast cancer.

Identification of DTL as Related Biomarker and Immune Infiltration Characteristics of Nasopharyngeal Carcinoma via Comprehensive Strategies

Purpose

Although considerable progress has been made in basic and clinical research on nasopharyngeal carcinoma (NPC), the biomarkers of the progression of NPC have not been fully studied and described. This study was designed to identify potential novel biomarkers for NPC using integrated analyses and explore the immune cell infiltration in this pathological process.

Methods

Five GEO data sets were downloaded from gene expression omnibus database (GEO) and analysed to identify differentially expressed genes (DEGs), followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The four algorithms were adopted for screening of novel and key biomarkers for NPC, including random forest (RF) machine learning algorithm, least absolute shrinkage and selection operator (LASSO) logistic regression, support vector machine-recursive feature elimination (SVM-RFE), and weighted gene co-expression network analysis (WGCNA). Lastly, CIBERSORT was used to assess the infiltration of immune cells in NPC, and the correlation between diagnostic markers and infiltrating immune cells was analyzed.

Results

Herein, we identified 46 DEGs, and enrichment analysis results showed that DEGs and several kinds of signaling pathways might be closely associated with the occurrence and progression of NPC. DTL was recognized as NPC-related biomarker. DTL, also known as retinoic acid-regulated nuclear matrix-associated protein (RAMP), or DNA replication factor 2 (CDT2), is reported to be correlated with the cell proliferation, cell cycle arrest and cell invasion in hepatocellular carcinoma, breast cancer and gastric cancer. Immune infiltration analysis demonstrated that macrophages M0, macrophages M1 and T cells CD4 memory activated were linked to pathogenesis of NPC.

Conclusion

In summary, we adopted a comprehensive strategy to screen DTL as biomarkers related to NPC and explore the critical role of immune cell infiltration in NPC.

Tamibarotene inhibit the accumulation of fibrocyte and alleviate renal fibrosis by IL-17A

Renal fibrosis is a common pathological process in the progression of chronic kidney disease. Accumulating evidence suggests that interleukin-17A (IL‐17A) and fibrocytes play crucial roles in the pathogenesis of fibrosis. However, the role of IL-17A in the regulation of renal fibrocytes in renal fibrosis has rarely been reported. Here, we report that the plasma IL-17A level is increased in immunoglobulin A nephropathy (IgAN) patients and is correlated with clinical parameters. Using a mouse model of unilateral ureteral obstruction (UUO), we found that both IL-17A expression and fibrocyte infiltration were increased in the kidneys of UUO mice. Besides, IL-17A enhanced fibrosis and fibrocyte-associated chemokine and activator expression in vitro. Furthermore, inhibition of IL-17A using Am80 (Tamibarotene) decreased fibrocytes and fibrocyte-associated chemokine and activator expression and significantly attenuated renal fibrosis in the UUO mice. Our findings suggest that Am80, which inhibits the accumulation of fibrocytes and alleviates renal fibrosis mediated by IL-17A, maybe a novel therapeutic drug for renal fibrosis.

The potential role and status of IL-17 family cytokines in breast cancer

Breast cancer (BC) is currently the most common malignant tumor of women in the world. At present, the development of BC is accelerating and showing a younger trend, which may be due to the known and/or unknown risk factors (RFs) for BC are increasing. It has been reported that inflammatory factors promote the occurrence and development of BC. No doubt chronic inflammation could trigger a series of molecular events, which will lead to the malignant transformation of differentiated cells, inhibition of anti-tumor immunity, and finally, lead to the occurrence and metastasis of tumors. With the deepening of research, it has been found that pro-inflammatory cytokine-interleukin-17 (IL-17) is closely related to BC. It not only plays an important role in promoting tumor proliferation, invasion and metastasis, but also has a significant correlation with poor prognosis. Recently, it was reported that IL-17 is closely related to programmed death ligand 1 (PD-L1) in BC. Therefore, starting with the role of IL-17 family cytokines in BC, this paper briefly discusses the potential role and status of IL-17 and seeks to contribute to the development of targeted drugs for BC-related treatments and to the identification of prediction factors for the early detection and prognosis prediction of BC for laying a solid theoretical foundation.

The Role of Inflammation in Breast and Prostate Cancer Metastasis to Bone

Tumor metastasis to bone is a common event in multiple forms of malignancy. Inflammation holds essential functions in homeostasis as a defense mechanism against infections and is a strategy to repair injured tissue and to adapt to stress conditions. However, exaggerated and/or persistent (chronic) inflammation may eventually become maladaptive and evoke diseases such as autoimmunity, diabetes, inflammatory tissue damage, fibrosis, and cancer. In fact, inflammation is now considered a hallmark of malignancy with prognostic relevance. Emerging studies have revealed a central involvement of inflammation in several steps of the metastatic cascade of bone-homing tumor cells through supporting their survival, migration, invasion, and growth. The mechanisms by which inflammation favors these steps involve activation of epithelial-to-mesenchymal transition (EMT), chemokine-mediated homing of tumor cells, local activation of osteoclastogenesis, and a positive feedback amplification of the protumorigenic inflammation loop between tumor and resident cells. In this review, we summarize established and evolving concepts of inflammation-driven tumorigenesis, with a special focus on bone metastasis.

The Role of Tumor Microenvironment in Cancer Metastasis: Molecular Mechanisms and Therapeutic Opportunities

Simple Summary

Metastasis, the process by which cancer cells escape primary tumor site and colonize distant organs, is responsible for most cancer-related deaths. The tumor microenvironment (TME), comprises different cell types, including immune cells and cancer-associated fibroblasts, as well as structural elements, such as collagen and hyaluronan that constitute the extracellular matrix (ECM). Intratumoral interactions between the cellular and structural components of the TME regulate the aggressiveness, and dissemination of malignant cells and promote immune evasion. At the secondary site, the TME also facilitates escape from dormancy to enhance metastatic tumor outgrowth. Moreover, the ECM applies mechanical forces on tumors that contribute to hypoxia and cancer cell invasiveness whereas also hinders drug delivery and efficacy in both primary and metastatic sites. In this review, we summarize the latest developments regarding the role of the TME in cancer progression and discuss ongoing efforts to remodel the TME to stop metastasis in its tracks.

Abstract

The tumor microenvironment (TME) regulates essential tumor survival and promotion functions. Interactions between the cellular and structural components of the TME allow cancer cells to become invasive and disseminate from the primary site to distant locations, through a complex and multistep metastatic cascade. Tumor-associated M2-type macrophages have growth-promoting and immunosuppressive functions; mesenchymal cells mass produce exosomes that increase the migratory ability of cancer cells; cancer associated fibroblasts (CAFs) reorganize the surrounding matrix creating migration-guiding tracks for cancer cells. In addition, the tumor extracellular matrix (ECM) exerts determinant roles in disease progression and cancer cell migration and regulates therapeutic responses. The hypoxic conditions generated at the primary tumor force cancer cells to genetically and/or epigenetically adapt in order to survive and metastasize. In the circulation, cancer cells encounter platelets, immune cells, and cytokines in the blood microenvironment that facilitate their survival and transit. This review discusses the roles of different cellular and structural tumor components in regulating the metastatic process, targeting approaches using small molecule inhibitors, nanoparticles, manipulated exosomes, and miRNAs to inhibit tumor invasion as well as current and future strategies to remodel the TME and enhance treatment efficacy to block the detrimental process of metastasis.

Interleukins as Mediators of the Tumor Cell-Bone Cell Crosstalk during the Initiation of Breast Cancer Bone Metastasis

Patients with advanced breast cancer are at high risk of developing bone metastasis. Despite treatment advances for primary breast cancer, metastatic bone disease remains incurable with a low relative survival. Hence, new therapeutic approaches are required to improve survival and treatment outcome for these patients. Bone is among the most frequent sites of metastasis in breast cancer. Once in the bone, disseminated tumor cells can acquire a dormant state and remain quiescent until they resume growth, resulting in overt metastasis. At this stage the disease is characterized by excessive, osteoclast-mediated osteolysis. Cells of the bone microenvironment including osteoclasts, osteoblasts and endothelial cells contribute to the initiation and progression of breast cancer bone metastasis. Direct cell-to-cell contact as well as soluble factors regulate the crosstalk between disseminated breast cancer cells and bone cells. In this complex signaling network interleukins (ILs) have been identified as key regulators since both, cancer cells and bone cells secrete ILs and express corresponding receptors. ILs regulate differentiation and function of bone cells, with several ILs being reported to act pro-osteoclastogenic. Consistently, the expression level of ILs (e.g., in serum) has been associated with poor prognosis in breast cancer. In this review we discuss the role of the most extensively investigated ILs during the establishment of breast cancer bone metastasis and highlight their potential as therapeutic targets in preventing metastatic outgrowth in bone.

Construction and validation of a 6-gene nomogram discriminating lung metastasis risk of breast cancer patients

Breast cancer is the most common malignant disease in women. Metastasis is the foremost cause of death. Breast tumor cells have a proclivity to metastasize to specific organs. The lung is one of the most common sites of breast cancer metastasis. Therefore, we aimed to build a useful and convenient prediction tool based on several genes that may affect lung metastasis-free survival (LMFS). We preliminarily identified 319 genes associated with lung metastasis in the training set GSE5327 (n = 58). Enrichment analysis of GO functions and KEGG pathways was conducted based on these genes. The best genes for modeling were selected using a robust likelihood-based survival modeling approach: GOLGB1, TMEM158, CXCL8, MCM5, HIF1AN, and TSPAN31. A prognostic nomogram for predicting lung metastasis in breast cancer was developed based on these six genes. The effectiveness of the nomogram was evaluated in the training set GSE5327 and the validation set GSE2603. Both the internal validation and the external validation manifested the effectiveness of our 6-gene prognostic nomogram in predicting the lung metastasis risk of breast cancer patients. On the other hand, in the validation set GSE2603, we found that neither the six genes in the nomogram nor the risk predicted by the nomogram were associated with bone metastasis of breast cancer, preliminarily suggesting that these genes and nomogram were specifically associated with lung metastasis of breast cancer. What's more, five genes in the nomogram were significantly differentially expressed between breast cancer and normal breast tissues in the TIMER database. In conclusion, we constructed a new and convenient prediction model based on 6 genes that showed practical value in predicting the lung metastasis risk for clinical breast cancer patients. In addition, some of these genes could be treated as potential metastasis biomarkers for antimetastatic therapy in breast cancer. The evolution of this nomogram will provide a good reference for the prediction of tumor metastasis to other specific organs.

Deep learning of the role of interleukin IL-17 and its action in promoting cancer

In breast cancer patients, metastasis remains a major cause of death. The metastasis formation process is given by an interaction between the cancer cells and the microenvironment that surrounds them. In this article, we develop a mathematical model that analyzes the role of interleukin IL-17 and its action in promoting cancer and in facilitating tissue metastasis in breast cancer, using a dynamic analysis based on a stochastic process that accounts for the local and global action of this molecule. The model uses the Ornstein–Uhlembeck and Markov process in continuous time. It focuses on the oncological expansion and the interaction between the interleukin IL-17 and cell populations This analysis tends to clarify the processes underlying the metastasis expansion mechanism both for a better understanding of the pathological event and for a possible better control of therapeutic strategies.

IL-17 is a proinflammatory interleukin that acts when there is tissue damage or when there is a pathological situation caused by an external pathogen or by a pathological condition such as cancer.

This research is focused on the role of interleukin IL-17 which, especially in the case of breast cancer, turns out to be a dominant “communication pin” since it interconnects with the activity of different cell populations affected by the oncological phenomenon. Stochastic modeling strategies, specially the Ornstein-Uhlenbeck process, with the aid of numerical algorithms are elaborated in this review.

The role of IL-17 is discussed in this manuscript at all the stages of cancer. It is discussed that IL-17 also acts as “metastasis promoter” as a result of its proinflammatory nature. The stochastic nature of IL-17 is discussed based on the evidence provided by recent literature.

The resulting dynamical analysis can help to select the most appropriate therapeutic strategy.

Cancer cells, in the case of breast cancer, have high level of IL-17 receptors (IL-17R); therefore the interleukin itself has direct effects on these cells. Immunotherapy research, focused on this cytokine and interlinked with the stochastic modeling, seems to be a promising avenue.

Molecular mechanisms and clinical management of cancer bone metastasis

As one of the most common metastatic sites of malignancies, bone has a unique microenvironment that allows metastatic tumor cells to grow and flourish. The fenestrated capillaries in the bone, bone matrix, and bone cells, including osteoblasts and osteoclasts, together maintain the homeostasis of the bone microenvironment. In contrast, tumor-derived factors act on bone components, leading to subsequent bone resorption or excessive bone formation. The various pathways involved also provide multiple targets for therapeutic strategies against bone metastases. In this review, we summarize the current understanding of the mechanism of bone metastases. Based on the general process of bone metastases, we specifically highlight the complex crosstalk between tumor cells and the bone microenvironment and the current management of cancer bone metastases.

The Interleukin-17 Family of Cytokines in Breast Cancer

Breast cancer (BC) is the most common cancer in women worldwide and remains a major cause of mortality with an expected 137,000 death this year in Europe. Standard management of metastatic BC comprises hormonotherapy, chemotherapy, and targeted therapies. Cyclin dependent kinase (CDK) and mammalian target of rapamycin (mTOR) inhibitors have recently proved their efficiency in hormonal receptor expressing BC. Checkpoint proteins inhibition is being evaluated in phase 3 studies. Since inflammation is constantly present in cancers, research teams have focused their attention on the interleukin-17 (IL-17) family of proinflammatory cytokines. Preclinical experiments have reported both pro and antitumor effects depending on the conditions. In the present article, we review the accumulating evidences about the roles of IL-17 in BC and discuss whether this family of cytokines could be a new target in anticancer treatments.

Breast Cancer Metastasis: Are Cytokines Important Players During Its Development and Progression?

In breast cancer, an uncontrolled cell proliferation leads to tumor formation and development of a multifactorial disease. Metastasis is a complex process that involves tumor spread to distant parts of the body from its original site. Metastatic dissemination represents the main physiopathology of cancer. Inter- and intracellular communication in all systems in vertebrates is mediated by cytokines, which are highly inducible, secretory proteins, produced not only by immune system cells, but also by endocrine and nervous system cells. It has become clear in recent years that cytokines, as well as their receptors are produced in the organisms under physiological and pathological conditions; recently, they have been closely related to breast cancer metastasis. The exact initiation process of breast cancer metastasis is unknown, although several hypotheses have emerged. In this study, we thoroughly reviewed the role of several cytokines in breast cancer metastasis. Data reviewed suggest that cytokines and growth factors are key players in the breast cancer metastasis induction. This knowledge must be considered with the aim to development of new therapeutic approaches to counter breast cancer metastasis.

BET proteins in abnormal metabolism, inflammation, and the breast cancer microenvironment

Obesity and its associated pathology Type 2 diabetes are two chronic metabolic and inflammatory diseases that promote breast cancer progression, metastasis, and poor outcomes. Emerging critical opinion considers unresolved inflammation and abnormal metabolism separately from obesity; settings where they do not co-occur can inform disease mechanism. In breast cancer, the tumor microenvironment is often infiltrated with T effector and T regulatory cells programmed by metabolic signaling. The pathways by which tumor cells evade immune surveillance, immune therapies, and take advantage of antitumor immunity are poorly understood, but likely depend on metabolic inflammation in the microenvironment. Immune functions are abnormal in metabolic disease, and lessons learned from preclinical studies in lean and metabolically normal environments may not translate to patients with obesity and metabolic disease. This problem is made more urgent by the rising incidence of breast cancer among women who are not obese but who have metabolic disease and associated inflammation, a phenotype common in Asia. The somatic BET proteins, comprising BRD2, BRD3, and BRD4, are new critical regulators of metabolism, coactivate transcription of genes that encode proinflammatory cytokines in immune cell subsets infiltrating the microenvironment, and could be important targets in breast cancer immunotherapy. These transcriptional coregulators are well known to regulate tumor cell progression, but only recently identified as critical for metabolism, metastasis, and expression of immune checkpoint molecules. We consider interrelationships among metabolism, inflammation, and breast cancer aggressiveness relevant to the emerging threat of breast cancer among women with metabolic disease, but without obesity.

IL17A Regulates Tumor Latency and Metastasis in Lung Adeno and Squamous SQ.2b and AD.1 Cancer

Somatic mutations can promote malignant transformation of airway epithelial cells and induce inflammatory responses directed against resultant tumors. Tumor-infiltrating T lymphocytes (TIL) in early-stage non-small cell lung cancer (NSCLC) secrete distinct proinflammatory cytokines, but the contribution of these TILs to tumor development and metastasis remains unknown. We show here that TILs in early-stage NSCLC are biased toward IL17A expression (Th17) when compared with adjacent tumor-free tissue, whereas Th17 cells are decreased in tumor infiltrating locoregional lymph nodes in advanced NSCLC. Mice in which Pten and Smad4 (Pts4d/d ) are deleted from airway epithelial cells develop spontaneous tumors, that share genetic signatures with squamous- (SQ.2b), and adeno- (AD.1) subtypes of human NSCLC. Pts4d/d mice globally lacking in IL17a (Pts4d/dIl17a-/- ) showed decreased tumor latency and increased metastasis. Th17 cells were required for recruitment of CD103+ dendritic cells, and adoptive transfer of IL17a-sufficient CD4+ T cells reversed early tumor development and metastasis in Pts4d/dIl17a-/- mice. Together, these findings support a key role for Th17 cells in TILs associated with the Pts4d/d model of NSCLC and suggest therapeutic and biomarker strategies for human SQ2b and AD1 lung cancer. Cancer Immunol Res; 6(6); 645-57. ©2018 AACR.

Inhibition of SERPINE2/protease nexin-1 by a monoclonal antibody attenuates airway remodeling in a murine model of asthma

SERPINE2, also known as protease nexin-1 (PN-1), is a serine protease inhibitor produced by many cell types and has pleiotropic biological functions. It has been reported that SERPINE2/PN-1 is involved in tissue remodeling of fibrotic diseases including idiopathic pulmonary fibrosis and cardiac fibrosis. However, the potential role of SERPINE2/PN-1 in asthmatic airway remodeling has remained barely investigated so far. In this study, BALB/c male mice were sensitized and challenged by ovalbumin to generate murine models of airway remodeling. Anti-SERPINE2 monoclonal antibody was intraperitoneally injected into these mice during the ovalbumin challenge while IgG antibody was used as a vehicle control. The results revealed that the expression of SERPINE2/PN-1 was significantly upregulated in the lung extracts of ovalbumin-challenged mice, and this upregulation was inhibited by dexamethasone. Sustained ovalbumin stimulation increased the thickness of airway wall and α-SMA positive areas in lung, which was attenuated by the treatment with SERPINE2 antibody. In addition, SERPINE2 antibody partially blocked the phosphorylation of ERK, and reduced the upregulation of MMP-9 and TIMP-1 expressions in asthmatic mice. These findings suggest that SERPINE2/PN-1 may play a role in the pathologic development of airway remodeling. Monoclonal antibody against SERPINE2 may have the potential as an effective pharmacotherapy for asthmatic airway remodeling.

Expression of CXCR4 on T-cell subsets and Plasma IL-17 Concentrations in Patients with Aplastic Anaemia

Acquired aplastic anaemia (AA) is caused by T-cells migrating to and attacking bone marrow (BM) in response to chemokines (e.g., CXCR4). We investigated CXCR4 expressions on circulating T-cell subsets, plasma IL-17A concentrations, and their correlations with AA manifestations. We enrolled 71 patients with acquired AA (36 severe AA cases [SAA] and 35 non-severe AA cases [NSAA]) and 42 healthy volunteers. We used flow cytometry and ELISA to measure circulating CD4⁺ and CD8⁺ T-cells, their CXCR4 expressions, and plasma IL-17A concentrations. Compared to the healthy controls, SAA patients had fewer peripheral CD4⁺ T-cells, more CD8⁺ T-cells, and a significantly decreased CD4⁺/CD8⁺ ratio which was positively correlated with AA manifestations. Patients with SAA or NSAA had higher proportions of CD4⁺CXCR4⁺ and CD8⁺CXCR4⁺ T-cells, which were negatively correlated with haemoglobin concentrations and absolute neutrophil counts. Patients with SAA or NSAA had higher plasma IL-17A concentrations, which were negatively correlated with AA manifestations and the CD4⁺/CD8⁺ ratio. IL-17A concentrations showed a very week correlation with CD4⁺CXCR4⁺ T-cells frequencies, and no correlation with CD8⁺CXCR4⁺ T-cells frequencies. Aberrant CXCR4 expression may allow circulating T-cells, especially CD8⁺ T-cells, to infiltrate BM during AA progression. Elevated IL-17A concentrations may contribute to AA progression outside of the CXCR4-SDF-1α axis.

The sleeping ugly: Tumour microenvironment's act to make or break the spell of dormancy

Metastasis is the main cause of death for most cancer patients. It appears clear from clinical observations that the majority of cancers, particularly carcinoma do not follow a linear model of metastatic progression, where cancer cells shed from the primary tumour, disseminate to a distant organ and immediately outgrow to form clinical metastasis. Certainly, while cancer spreading is an early event, metastasis occurs much later during tumour progression and frequently arises several years after primary tumour resection. The time spent by disseminated cancer cells (DTCs) in a distant organ before their outgrowth is termed metastatic latency. We will examine here the current knowledge of the mechanisms allowing metastatic latency and discuss the crucial role of the DTCs' tissue microenvironment in this process.

Receptor activator of nuclear factor kappa B (RANK) expression in primary breast cancer correlates with recurrence-free survival and development of bone metastases in I-SPY1 (CALGB 150007/150012; ACRIN 6657)

PURPOSE

The receptor activator of nuclear factor kappa B (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) axis may contribute to the development of bone metastases (BM). We studied gene expression in this pathway in primary breast cancer (BC) to determine correlations with clinical characteristics and outcomes in the neoadjuvant I-SPY1 study.

METHODS

We evaluated RANK/RANKL/OPG expression using expression microarrays in I-SPY1 (n = 149). Associations with clinical features were determined using t test and ANOVA. Associations between biomarker high versus low groups (dichotomized at an optimal cutpoint) and recurrence-free survival (RFS) were evaluated using the log-rank test and in a multivariate Cox proportional hazard model. A pooled external neoadjuvant cohort with gene expression data (GSE25066) (Hatzis et al. in JAMA 305(18):1873-1881, 30) (n = 425) was used for validation. Associations with site-specific relapse were evaluated using the t-test and multivariate logistic regression adjusting for hormone receptor (HR) status.

RESULTS

RANK was significantly higher in HR negative versus HR positive (p = 0.027), in basal versus non-basal disease (p = 0.004), and in those achieving pathologic complete response (p = 0.038); the associations with HR negative and basal BC were also significant in GSE25066. In both datasets, higher RANK associated with significantly worse RFS (I-SPY1: p = 0.045, GSE25066: p = 0.044). However, this association did not remain significant after adjusting for HR status. In I-SPY1 patients with recurrence, higher RANK correlated with BM versus non-BM (p = 0.045), even after adjusting for HR status (p = 0.035).

CONCLUSIONS

RANK is increased in HR negative and basal BC, and correlates with worse RFS and risk of BM. The RANK pathway is a potential therapeutic target in BC.

PLA2G7 associates with hormone receptor negativity in clinical breast cancer samples and regulates epithelial-mesenchymal transition in cultured breast cancer cells

Breast cancer is the leading cause of cancer‐related deaths in women due to distinct cancer subtypes associated with early recurrence and aggressive metastatic progression. High lipoprotein‐associated phospholipase A2 (PLA2G7) expression has previously been associated with aggressive disease and metastasis in prostate cancer. Here, we explore the expression pattern and functional role of PLA2G7 in breast cancer. First, a bioinformatic analysis of genome‐wide gene expression data from 970 breast samples was carried out to evaluate the expression pattern of PLA2G7 mRNA in breast cancer. Second, the expression profile of PLA2G7 was studied in 1042 breast cancer samples including 89 matched lymph node metastasis samples using immunohistochemistry. Third, the effect of PLA2G7 silencing on genome‐wide gene expression profile was studied and validated in cultured breast cancer cells expressing PLA2G7 at high level. Last, the expression pattern of PLA2G7 mRNA was investigated in 24 nonmalignant tissue samples and 65 primary and 7 metastatic tumour samples derived from various organs using qRT‐PCR. The results from clinical breast cancer samples indicated that PLA2G7 is overexpressed in a subset of breast cancer samples compared to its expression in benign breast tissue samples and that high PLA2G7 expression associated with hormone receptor negativity as well as with poor prognosis in a subset of breast cancer samples. In vitro functional studies highlighted the putative role of PLA2G7 in the regulation of epithelial‐mesenchymal transition (EMT)‐related signalling pathways, vimentin and E‐cadherin protein expression as well as cell migration in cultured breast cancer cells. Furthermore, supporting the findings in breast and prostate cancer, high PLA2G7 mRNA expression was associated with metastatic cancer in four additional organs of origin. In conclusion, our results indicate that PLA2G7 is highly expressed in a subset of metastatic and aggressive breast cancers and in metastatic samples of various tissues of origin and promotes EMT and migration in cultured breast cancer cells.

BET bromodomain proteins and epigenetic regulation of inflammation: implications for type 2 diabetes and breast cancer

Chronic inflammation drives pathologies associated with type 2 diabetes (T2D) and breast cancer. Obesity-driven inflammation may explain increased risk and mortality of breast cancer with T2D reported in the epidemiology literature. Therapeutic approaches to target inflammation in both T2D and cancer have so far fallen short of the expected improvements in disease pathogenesis or outcomes. The targeting of epigenetic regulators of cytokine transcription and cytokine signaling offers one promising, untapped approach to treating diseases driven by inflammation. Recent work has deeply implicated the Bromodomain and Extra-Terminal domain (BET) proteins, which are acetylated histone "readers", in epigenetic regulation of inflammation. This review focuses on inflammation associated with T2D and breast cancer, and the possibility of targeting BET proteins as an approach to regulating inflammation in the clinic. Understanding inflammation in the context of BET protein regulation may provide a basis for designing promising therapeutics for T2D and breast cancer.

Effect of stromal cell-derived factor-1 on myocardial apoptosis and cardiac function recovery in rats with acute myocardial infarction

The aim of the study was to investigate the effect of stromal cell-derived factor-1 (SDF-1) on myocardial apoptosis and cardiac function recovery in rats with acute myocardial infarction (AMI) and the mechanism of the Toll-like receptor (TLR)-4/nuclear factor-κB (NF-κB) signaling pathway. A total of 64 healthy male F344 rats were randomly divided into the sham operation, model, SDF-1 intervention and SDF-1 antibody groups, with 16 rats in each group. The method of Olivette was used to establish the AMI model by ligation of the left anterior descending artery. Day 1 after establishing the animal model, the rats in the SDF-1 intervention group were injected with 10 µl recombinant SDF-1 (400 ng/ml) in five regions including the myocardial infarction area and the four surrounding areas. The rats in the model group were injected with 10 µl normal saline including the myocardial infarction area and the four surrounding areas, and those in the SDF-1 antibody group were injected with 1 ml SDF-1 antibody (2 µg/ml). Four rats were sacrificed after 1, 3, 7 and 14 days after the intervention, and the analysis was carried out. TUNEL in situ labeled apoptotic cells were used for cell counting, and immunohistochemical staining was performed to measure vascular density. The animal echocardiographic measurement was for the left ventricular end-diastolic diameter (LVEDd), left ventricular end-systolic diameter (LVESd), left ventricular fractional shortening (FS) and ejection fraction (EF) values. The results showed that the number of apoptotic cells in the SDF-1 treatment group was significantly lower than those in the other groups at each time-point. The vessel densities in the 3–14 days were significantly greater than those in other groups. At each time-point, the LVEDd and LVESd values were smaller compared with the model group, but greater than the sham operation group and decreased over time. FS and EF values were higher than those in the model group at each time-point, but less than those of the sham operation group and increased over time. The expression levels of TLR-4 and NF-κB at each time-point were significantly higher than those of the remaining groups (p<0.05). In conclusion, SDF-1 is capable of decreasing the apoptosis of cardiac muscle cells in AMI, promoting angiogenesis and improving cardiac function, which may be associated with the activation of the TLR-4/NF-κB signaling pathway.

Nrf2 Induces IL-17D to Mediate Tumor and Virus Surveillance

Cells undergoing xenobiotic or oxidative stress activate the transcription factor nuclear factor erythroid-derived 2-like 2 (Nrf2), which initiates an intrinsic "stress surveillance" pathway. We recently found that the cytokine IL-17D effects a form of extrinsic stress surveillance by inducing antitumor immunity, but how IL-17D is regulated remains unknown. Here, we show that Nrf2 induced IL-17D in cancer cell lines. Moreover, both Nrf2 and IL-17D were induced in primary tumors as well as during viral infection in vivo. Expression of IL-17D in tumors and virally infected cells is essential for optimal protection of the host as il17d(-/-) mice experienced a higher incidence of tumors and exacerbated viral infections compared to wild-type (WT) animals. Moreover, activating Nrf2 to induce IL-17D in established tumors led to natural killer cell-dependent tumor regression. These data demonstrate that Nrf2 can initiate both intrinsic and extrinsic stress surveillance pathways and highlight the use of Nrf2 agonists as immune therapies for cancer and infection.

Progression of fibrosis in patients with chronic viral hepatitis is associated with IL-17(+) neutrophils

BACKGROUND & AIMS

The pro-inflammatory cytokine IL-17 plays a crucial role in liver diseases associated with hepatic fibrosis and increased risk of cancer development. Nevertheless, the cellular source of this cytokine has never been characterized in patients with liver fibrosis.

METHODS

In this study, we investigated liver biopsies from 49 patients with chronic viral hepatitis at different stages of liver fibrosis. We monitored IL-17 production by intracellular flow cytometry, immunofluorescence and immunohistochemical in situ stainings, allowing a precise quantification, characterization and localization of IL-17(+) cells.

RESULTS

Density of IL-17(+) cells increased with the stage of liver fibrosis specifically in fibrotic septa and portal areas (correlation coefficient r = 0.7373; P < 0.0001). Data clearly show that the frequency of intrahepatic IL-17(+) lymphocytes (including T, NKT and NK cells) was independent on stage of liver fibrosis, and we observed no statistical differences in number of IL-17(+) macrophages during progression of fibrosis. On the other hand, the number of IL-17(+) neutrophils in fibrotic septa and portal areas strongly correlated with the stages of fibrosis (correlation coefficient r = 0.6986; P < 0.0001), contributing significantly to total IL-17 production in liver tissue.

CONCLUSIONS

Our data indicate that neutrophils represent an important source of IL-17 in the human liver, especially in late fibrosis stages. Inhibition of this specific harmful subset of neutrophils may offer therapeutic opportunities in fibrotic liver.

Chemokine receptor patterns in lymphocytes mirror metastatic spreading in melanoma

Melanoma prognosis is dictated by tumor-infiltrating lymphocytes, the migratory and functional behavior of which is guided by chemokine or cytokine gradients. Here, we retrospectively analyzed the expression patterns of 9 homing receptors (CCR/CXCR) in naive and memory CD4+ and CD8+ T lymphocytes in 57 patients with metastatic melanoma (MMel) with various sites of metastases to evaluate whether T cell CCR/CXCR expression correlates with intratumoral accumulation, metastatic progression, and/or overall survival (OS). Homing receptor expression on lymphocytes strongly correlated with MMel dissemination. Loss of CCR6 or CXCR3, but not cutaneous lymphocyte antigen (CLA), on circulating T cell subsets was associated with skin or lymph node metastases, loss of CXCR4, CXCR5, and CCR9 corresponded with lung involvement, and a rise in CCR10 or CD103 was associated with widespread dissemination. High frequencies of CD8+CCR9+ naive T cells correlated with prolonged OS, while neutralizing the CCR9/CCL25 axis in mice stimulated tumor progression. The expansion of CLA-expressing effector memory CD8+ T cells in response to a single administration of CTLA4 blockade predicted disease control at 3 months in 47 patients with MMel. Thus, specific CCR/CXCR expression patterns on circulating T lymphocytes may guide potential diagnostic and therapeutic approaches.

Serum-derived exosomes from mice with highly metastatic breast cancer transfer increased metastatic capacity to a poorly metastatic tumor

Altered interaction between CD200 and CD200R represents an example of “checkpoint blockade” disrupting an effective, tumor‐directed, host response in murine breast cancer cells. In CD200R1KO mice, long‐term cure of EMT6 breast cancer, including metastatic spread to lung and liver, was achieved in BALB/c mice. The reverse was observed with 4THM tumors, an aggressive, inflammatory breast cancer, with increased tumor metastasis in CD200R1KO. We explored possible explanations for this difference. We measured the frequency of circulating tumor cells (CTCs) in peripheral blood of tumor bearers, as well as lung/liver and draining lymph nodes. In some cases mice received infusions of exosomes from nontumor controls, or tumor bearers, with/without additional infusions of anticytokine antibodies. The measured frequency of circulating tumor cells (CTCs) in peripheral blood was equivalent in the two models in WT and CD200R1KO mice. Increased metastasis in EMT6 tumor bearers was seen in vivo following adoptive transfer of serum, or serum‐derived exosomes, from 4THM tumor bearers, an effect which was attenuated by anti‐IL‐6, and anti‐IL‐17, but not anti‐TNFα, antibody. Anti‐IL‐6 also attenuated enhanced migration of EMT6 cells in vitro induced by 4THM serum or exosomes, or recombinant IL‐6. Exosome cytokine proteomic profiles responses in 4THM and EMT6 tumor‐bearing mice were regulated by CD200:CD200R interactions, with attenuation of both IL‐6 and IL‐17 in 4THM CD200^tg mice, and enhanced levels in 4THM CD200R1KO mice. We suggest these cytokines act on the microenvironment at sites within the host, and/or directly on tumor cells themselves, to increase metastatic potential.

Interleukin-17 Could Promote Breast Cancer Progression at Several Stages of the Disease

Metastatic disease accounts for more than 90% of deaths from breast cancer. Yet the factors that trigger metastasis, often years after primary tumor removal, are not understood well. Recently the proinflammatory cytokine interleukin- (IL-) 17 family has been associated with poor prognosis in breast cancer. Here we review current literature on the pathogenic mechanisms driven by IL-17 during breast cancer progression and connect these findings to metastasis. These include (1) direct effects of IL-17 on tumor cells promoting tumor cell survival and invasiveness, (2) regulation of tumor angiogenesis, and (3) interaction with myeloid derived suppressor cells (MDSCs) to inhibit antitumor immune response and collaborate at the distant metastatic site. Furthermore, IL-17 might also be a culprit in bone destruction caused by late stage bone metastasis. Interestingly, in addition to these potential prometastasis functions, there is also evidence for an opposite, antitumor role of IL-17 during cancer therapies. We hypothesize that these contradictory roles may be due to chronic, imbalanced versus acute transient nature of the immune reactions, as well as differences in the cells that interact with IL-17⁺ cells under different circumstances.

Role of stromal cell-derived factor 1α pathway in bone metastatic prostate cancer

Metastatic prostate cancer is one of the leading causes of cancer-related death in men. The primary site of metastasis from prostate cancers is the bone. During the last decade, multiple studies have pointed to the role of the stromal cell-derived factor 1 alpha (SDF1α)/CXCR4 axis in the metastatic spread of the disease, but the mechanisms that underlie this effect are still incompletely understood. In this review, we summarize the current understanding of the role of the SDF1α/CXCR4 pathway in bone metastatic prostate cancer. We also discuss the therapeutic potential of disrupting the interaction between prostate tumor cells and bone environment with focus on the SDF1α pathway.

IL-17A Contributes to the Pathogenesis of Endometriosis by Triggering Proinflammatory Cytokines and Angiogenic Growth Factors

Endometriosis is a chronic, inflammatory disease characterized by the growth of endometrial tissue in aberrant locations outside the uterus. Neoangiogenesis or establishment of new blood supply is one of the fundamental requirements of endometriotic lesion survival in the peritoneal cavity. IL-17A is emerging as a potent angiogenic and proinflammatory cytokine involved in the pathophysiology of several chronic inflammatory diseases such as rheumatoid arthritis and psoriasis. However, sparse information is available in the context of endometriosis. In this study, we demonstrate the potential importance of IL-17A in the pathogenesis and pathophysiology of endometriosis. The data show a differential expression of IL-17A in human ectopic endometriotic lesions and matched eutopic endometrium from women with endometriosis. Importantly, surgical removal of lesions resulted in significantly reduced plasma IL-17A concentrations. Immunohistochemistry revealed localization of IL-17A primarily in the stroma of matched ectopic and eutopic tissue samples. In vitro stimulation of endometrial epithelial carcinoma cells, Ishikawa cells, and HUVECs with IL-17A revealed significant increase in angiogenic (vascular endothelial growth factor and IL-8), proinflammatory (IL-6 and IL-1β), and chemotactic cytokines (G-CSF, CXCL12, CXCL1, and CX3CL1). Furthermore, IL-17A promoted tubulogenesis of HUVECs plated on Matrigel in a dose-dependent manner. Thus, we provide the first evidence, to our knowledge, that endometriotic lesions produce IL-17A and that the removal of the lesion via laparoscopic surgery leads to the significant reduction in the systemic levels of IL-17A. Taken together, our data show a likely important role of IL-17A in promoting angiogenesis and proinflammatory environment in the peritoneal cavity for the establishment and maintenance of endometriosis lesions.

Effect of IL-17A on the migration and invasion of NPC cells and related mechanisms

In carcinogenesis, inflammasomes may play contradictory roles through facilitating anti-tumor immunity or inducing oncogenic factors. Their function in cancer remains poorly characterized. In this study, we explored the effect of interleukin-17A (IL-17A) on the migration and invasion activity of nasopharyngeal carcinoma (NPC) cell lines and account for related mechanisms. Our results revealed that exogenous IL-17A promoted cell migration and invasion significantly in both NPC-039 and CNE-2Z cell lines. In addition, the expression of matrix metalloproteinase-2 (MMP-2)/-9 and Vimentin could be elevated by IL-17A stimulation; meanwhile the expression of E-cadherin was decreased. The results also show that IL-17A could activate the p38 signaling pathway in IL-17A-stimulated NPC-039 and CNE-2Z cell lines. Combining treatment with a p38 inhibitor (SB203580) resulted in decreased invasion capabilities of NPC-039 and CNE-2Z cell lines. SB203580 also inhibited the expression of MMP-2/-9 and increased the expression of E-cadherin in IL-17A-stimulated NPC-039 and CNE-2Z cell lines. IL-17A also could activate NF-κB in NPC-039 and CNE-2Z cell lines. In summary, our data show that IL-17A promote the cell migration and invasion of NPC cells. The effect of IL-17A on cell migration and invasion may be mediated via regulation of the expression of MMP-2/-9 and epithelial-mesenchymal transition (EMT) via p38-NF-κB signaling pathway. Thus, IL-17A or its related signaling pathways may be a promising target for preventing and inhibiting NPC metastasis.

The role of chemoattractant receptors in shaping the tumor microenvironment

Chemoattractant receptors are a family of seven transmembrane G protein coupled receptors (GPCRs) initially found to mediate the chemotaxis and activation of immune cells. During the past decades, the functions of these GPCRs have been discovered to not only regulate leukocyte trafficking and promote immune responses, but also play important roles in homeostasis, development, angiogenesis, and tumor progression. Accumulating evidence indicates that chemoattractant GPCRs and their ligands promote the progression of malignant tumors based on their capacity to orchestrate the infiltration of the tumor microenvironment by immune cells, endothelial cells, fibroblasts, and mesenchymal cells. This facilitates the interaction of tumor cells with host cells, tumor cells with tumor cells, and host cells with host cells to provide a basis for the expansion of established tumors and development of distant metastasis. In addition, many malignant tumors of the nonhematopoietic origin express multiple chemoattractant GPCRs that increase the invasiveness and metastasis of tumor cells. Therefore, GPCRs and their ligands constitute targets for the development of novel antitumor therapeutics.