Ets-1 enhances tumor migration through regulation of CCR7 expression

Mechanoresponsive ETS1 causes endothelial dysfunction and arterialization in varicose veins via NOTCH4/DLL4 signaling

Varicose veins are the most common venous disorder in humans and are characterized by hemodynamic instability due to valvular insufficiency and orthostatic lifestyle factors. It is unclear how changes in biomechanical signals cause aberrant remodeling of the vein wall. Our previous studies suggest that Notch signaling is implicated in varicose vein arterialization. In the arterial system, mechanoresponsive ETS1 is a transcriptional activator of the endothelial Notch, but its involvement in sensing disrupted venous flow and varicose vein formation has not been investigated. Here, we use human varicose veins and cultured human venous endothelial cells to show that disturbed venous shear stress activates ETS1-NOTCH4/DLL4 signaling. Notch components were highly expressed in the neointima, whereas ETS1 was upregulated in all histological layers of varicose veins. In vitro microfluidic flow-based studies demonstrate that even minute changes in venous flow patterns enhance ETS1-NOTCH4/DLL4 signaling. Uniform venous shear stress, albeit an inherently low-flow system, does not induce ETS1 and Notch proteins. ETS1 activation under altered flow was mediated primarily by MEK1/2 and, to a lesser extent, by MEK5 but was independent of p38 MAP kinase. Endothelial cell-specific ETS1 knockdown prevented disturbed flow-induced NOTCH4/DLL4 expression. TK216, an inhibitor of ETS-family, prevented the acquisition of arterial molecular identity and loss of endothelial integrity in cells exposed to the ensuing altered shear stress. We conclude that ETS1 senses blood flow disturbances and may promote venous remodeling by inducing endothelial dysfunction. Targeting ETS1 rather than downstream Notch proteins could be an effective and safe strategy to develop varicose vein therapies.

CCL19: a novel prognostic chemokine modulates the tumor immune microenvironment and outcomes of cancers

BACKGROUND

CCL19 is a chemokine involved in cancer research due to its important role in the tumor microenvironment (TME) and clinical relevance in cancers. This study aimed to analyze transcription expression, genomic alteration, association with tumor immune microenvironment of CCL19 expression and its prediction value for prognosis and responses to immunotherapy for patients with cancers.

METHODS

RNA sequencing data and corresponding clinicopathological information of a total of large-scale cancer patients were obtained from The Cancer Genome Atlas and Gene Expression Omnibus databases. Multiplex immunofluorescence (mIF) was implemented to identify differential infiltration of Treg, CD8+ T cells, and tumor-associated macrophages, while CCL19 immunohistochemistry was conducted on 182 breast cancer samples from a real-world cohort.

RESULTS

Based on large-scale multi-center survival analysis of cancer patients, we found the prognosis of patients with high CCL19 expression was prominently better than those with low CCL19 expression. For patients from multiple independent cohorts, suppressed CCL19 expression exerts significant progressive phenotype and apoptosis activity of cancers, especially in breast and ovarian cancer. Interestingly, anti-tumor immune cells, specifically the CD8+ T cells and macrophages, were clustered from TME by elevated CCL19 expression. Additionally, higher CCL19 levels reflected heightened immune activity and substantial heterogeneity.

CONCLUSIONS

In conclusion, our findings support the notion that elevated CCL19 expression is linked to favorable outcomes and enhanced anti-tumor immunity, characterized by increased CD8+ T cells within the TME. This suggests the potential of CCL19 as a prognostic marker, predictive biomarker for immunotherapy, therapeutic target of cancers.

Loss of ATRX promotes aggressive features of osteosarcoma with increased NF-κB signaling and integrin binding

Osteosarcoma (OS) is a lethal disease with few known targeted therapies. Here, we show that decreased ATRX expression is associated with more aggressive tumor cell phenotypes, including increased growth, migration, invasion, and metastasis. These phenotypic changes correspond with activation of NF-κB signaling, extracellular matrix remodeling, increased integrin αvβ3 expression, and ETS family transcription factor binding. Here, we characterize these changes in vitro, in vivo, and in a data set of human OS patients. This increased aggression substantially sensitizes ATRX-deficient OS cells to integrin signaling inhibition. Thus, ATRX plays an important tumor-suppression role in OS, and loss of function of this gene may underlie new therapeutic vulnerabilities. The relationship between ATRX expression and integrin binding, NF-κB activation, and ETS family transcription factor binding has not been described in previous studies and may impact the pathophysiology of other diseases with ATRX loss, including other cancers and the ATR-X α thalassemia intellectual disability syndrome.

Development of a human antibody that exhibits antagonistic activity toward CC chemokine receptor 7

Background

CC chemokine receptor 7 (CCR7) is a member of G-protein-coupled receptor family and mediates chemotactic migration of immune cells and different cancer cells induced via chemokine (C-C motif) ligand 19 (CCL19) or chemokine (C-C motif) ligand 21 (CCL21). Hence, the identification of blockade antibodies against CCR7 could lead to the development of therapeutics targeting metastatic cancer.

Methods

CCR7 was purified and stabilized in its active conformation, and antibodies specific to purified CCR7 were screened from the synthetic M13 phage library displaying humanized scFvs. The in vitro characterization of selected scFvs identified two scFvs that exhibited CCL19-competitive binding to CCR7. IgG4’s harboring selected scFv sequences were characterized for binding activity in CCR7+ cells, inhibitory activity toward CCR7-dependent cAMP attenuation, and the CCL19 or CCL21-dependent migration of CCR7+ cells.

Results

Antibodies specifically binding to purified CCR7 and CCR7+ cells were isolated and characterized. Two antibodies, IgG4(6RG11) and IgG4(72C7), showed ligand-dependent competitive binding to CCR7 with KD values of 40 nM and 50 nM, respectively. Particularly, IgG4(6RG11) showed antagonistic activity against CCR7, whereas both antibodies significantly blocked the ligand-induced migration and invasion activity of CCR7+ cancer cells.

Conclusions

Two antibody clones were successfully identified from a synthetic scFv-displaying phage library using purified recombinant CCR7 as an antigen. Antibodies specifically bound to the surface of CCR7+ cells and blocked CCR7+ cell migration. Particularly, 6RG11 showed antagonist activity against CCR7-dependent cAMP attenuation.

Statement of Significance

Antibodies targeting CCR7 were identified and could serve as therapeutic reagents against cancer metastasis.

New Insights of CCR7 Signaling in Dendritic Cell Migration and Inflammatory Diseases

CCR7, collaborated with its ligands CCL19 and CCL21, controls extensive migratory events in the immune system. CCR7-bearing dendritic cells can swarm into T-cell zones in lymph nodes, initiating the antigen presentation and T-cell response. Abnormal expression of CCR7 in dendritic cells will cause a series of inflammatory diseases due to the chaotic dendritic cell trafficking. In this review, we take an in-depth look at the structural–functional domains of CCR7 and CCR7-bearing dendritic cell trajectory to lymph nodes. Then, we summarize the regulatory network of CCR7, including transcriptional regulation, translational and posttranslational regulation, internalization, desensitization, and recycling. Furthermore, the potential strategies of targeting the CCR7 network to regulate dendritic cell migration and to deal with inflammatory diseases are integrated, which not only emphasizes the possibility of CCR7 to be a potential target of immunotherapy but also has an implication on the homing of dendritic cells to benefit inflammatory diseases.

C-C Chemokine Receptor 7 in Cancer

C-C chemokine receptor 7 (CCR7) was one of the first two chemokine receptors that were found to be upregulated in breast cancers. Chemokine receptors promote chemotaxis of cells and tissue organization. Since under homeostatic conditions, CCR7 promotes migration of immune cells to lymph nodes, questions immediately arose regarding the ability of CCR7 to direct migration of cancer cells to lymph nodes. The literature since 2000 was examined to determine to what extent the expression of CCR7 in malignant tumors promoted migration to the lymph nodes. The data indicated that in different cancers, CCR7 plays distinct roles in directing cells to lymph nodes, the skin or to the central nervous system. In certain tumors, it may even serve a protective role. Future studies should focus on defining mechanisms that differentially regulate the unfavorable or beneficial role that CCR7 plays in cancer pathophysiology, to be able to improve outcomes in patients who harbor CCR7-positive cancers.

UBQLN4 is activated by C/EBPβ and exerts oncogenic effects on colorectal cancer via the Wnt/β-catenin signaling pathway

Ubiquilin 4 (UBQLN4) is an important member of the ubiquitin-like protein family. An increasing number of studies have shown that UBQLN4 is an important regulator of tumorigenesis. Nevertheless, the biological function and detailed mechanisms of UBQLN4 in colorectal cancer (CRC) development and progression remain unclear. Here, we identified UBQLN4 upregulation in CRC tissues and it is positively associated with CRC size, TNM stage, and lymphatic metastasis. Patients with high UBQLN4 expression had a poor prognosis. Functionally, overexpression of UBQLN4 significantly promoted CRC cell proliferation, migration, and invasion, while UBQLN4 silencing elicited the opposite effect. This result was consistent with the conclusion that UBQLN4 expression correlated positively with the CRC size and lymphatic metastasis. In vivo, UBQLN4 silencing also inhibited tumor growth. Mechanistically, using gene set enrichment analysis (GSEA) and western blot experiments, we identified that UBQLN4 activated the Wnt/β-catenin signaling pathway to upregulate β-catenin and c-Myc expression, thereby promoting CRC proliferation, migration and invasion. A rescue experiment further verified this conclusion. Dual luciferase reporter, real-time quantitative PCR (RT-qPCR), western blot and chromatin immunoprecipitation (ChIP) assays indicated that the transcription factor CCAAT/enhancer-binding protein beta (C/EBPβ) directly bound to the UBQLN4 core promoter region and activated its transcription, upregulating β-catenin and c-Myc expression to promote CRC progression. Thus, our findings suggest that UBQLN4 is a key oncogene in CRC and may be a promising target for the diagnosis and treatment of patients with CRC.

The Roles of CCR7 for the Homing of Memory CD8+ T Cells into Their Survival Niches

Memory CD8+ T cells in the immune system are responsible for the removal of external Ags for a long period of time to protect against re-infection. Naïve to memory CD8+ T cell differentiation and memory CD8+ T cell maintenance require many different factors including local environmental factors. Thus, it has been suggested that the migration of memory CD8+ T cells into specific microenvironments alters their longevity and functions. In this review, we have summarized the subsets of memory CD8+ T cells based on their migratory capacities and described the niche hypothesis for their survival. In addition, the basic roles of CCR7 in conjunction with the migration of memory CD8+ T cells and recent understandings of their survival niches have been introduced. Finally, the applications of altering CCR7 signaling have been discussed.

The Role of CCL21/CCR7 Chemokine Axis in Breast Cancer Progression

Breast cancer is a leading cause of cancer-related deaths worldwide, predominantly caused by metastasis. It is generally accepted that the pattern of breast cancer metastasis is largely determined by the interaction between the chemokine receptors on cancer cells and the chemokines expressed at the sites of metastatic disease. Chemokine receptors belong to the G-protein-coupled receptors (GPCRs) family that appear to be implicated in inflammatory diseases, tumor growth and metastasis. One of its members, C-C Chemokine receptor 7 (CCR7), binds chemokines CCL19 and CCL21, which are important for tissue homeostasis, immune surveillance and tumorigenesis. These receptors have been shown to induce the pathobiology of breast cancer due to their ability to induce cellular proliferation and migration upon the binding of the cognate chemokine receptors. The underlying signaling pathways and exact cellular interactions within this biological system are not fully understood and need further insights. Thus, in this review, we summarize the essential roles of CCR7 and its receptors in breast cancer progression. Furthermore, we discuss the mechanisms of regulation that may lead to novel opportunities for therapeutic intervention. Despite the enormous advances in our knowledge of the nature of the chemokines in breast cancer metastasis, research about the involvement of CCR7 in cancer progression is still limited. Therefore, further studies are essential to illustrate the distinct roles of CCR7 in cancer progression and validate its potential as a preventive bio-factor for human breast cancer metastasis by targeting chemokine receptor genes.

Tumor microenvironment components: Allies of cancer progression

Cancer is a disease that affects millions of individuals worldwide and has a great impact on public health. Therefore, the study of tumor biology and an understanding of how the components of the tumor microenvironment behave and interact is extremely important for cancer research. Factors expressed by the components of the tumor microenvironment and induce angiogenesis have important roles in the onset and progression of the tumor. These components are represented by the extracellular matrix, fibroblasts, adipocytes, immune cells, and macrophages, besides endothelial cells, which modulate tumor cells and the tumor microenvironment to favor survival and the progression of cancer. The characteristics and function of the main stromal components and their mechanisms of interaction with the tumor cells that contribute to progression, tumor invasion, and tumor spread will be addressed in this review. Furthermore, reviewing these components is expected to indicate their importance as possible prognostic markers and therapeutic targets.