Chemokines

EGFR/Ras-induced CCL20 production modulates the tumour microenvironment

Background

The activation of the EGFR/Ras-signalling pathway in tumour cells induces a distinct chemokine repertoire, which in turn modulates the tumour microenvironment.

Methods

The effects of EGFR/Ras on the expression and translation of CCL20 were analysed in a large set of epithelial cancer cell lines and tumour tissues by RT-qPCR and ELISA in vitro. CCL20 production was verified by immunohistochemistry in different tumour tissues and correlated with clinical data. The effects of CCL20 on endothelial cell migration and tumour-associated vascularisation were comprehensively analysed with chemotaxis assays in vitro and in CCR6-deficient mice in vivo.

Results

Tumours facilitate progression by the EGFR/Ras-induced production of CCL20. Expression of the chemokine CCL20 in tumours correlates with advanced tumour stage, increased lymph node metastasis and decreased survival in patients. Microvascular endothelial cells abundantly express the specific CCL20 receptor CCR6. CCR6 signalling in endothelial cells induces angiogenesis. CCR6-deficient mice show significantly decreased tumour growth and tumour-associated vascularisation. The observed phenotype is dependent on CCR6 deficiency in stromal cells but not within the immune system.

Conclusion

We propose that the chemokine axis CCL20–CCR6 represents a novel and promising target to interfere with the tumour microenvironment, and opens an innovative multimodal strategy for cancer therapy.

Andrographolide Inhibits Angiogenesis by Inhibiting the Mir-21-5p/TIMP3 Signaling Pathway

Angiogenesis provides nutrients and oxygen to promote tumor growth and affords a channel that facilitates tumor cell entry into the circulation. Andrographolide (Andro) possess anti-tumor activity; however, its direct effect on angiogenesis still needs to be clarified. In this study, our experiments revealed that Andro significantly inhibited vascular growth in chick embryo chorioallantoic membrane (CAM) and yolk sac membrane (YSM) models. Meanwhile, tumor angiogenesis was also suppressed by Andro. Additionally, we found that cell proliferation, migration and tube formation of vascular endothelial cells was inhibited by Andro treatment in vitro. The effect was primarily mediated through inhibition of miR-21-5p expression and further targeting of TIMP3. This work provides evidence that Andro directly inhibits angiogenesis and might be an effective anti-angiogenic therapeutic drug for cancer treatment.

Inherited variants in the chemokine CCL2 gene and prostate cancer aggressiveness in a Caucasian cohort

PURPOSE

Though C-C chemokine ligand 2 (CCL2) has been shown to play a pivotal role in prostate cancer tumorigenesis and invasion, the role of inherited variation in the CCL2 gene in prostate cancer progression and metastases remains unanswered. This study is aimed to determine the influence of CCL2 germline variants on prostate cancer aggressiveness.

EXPERIMENTAL DESIGN

We performed an association study between six single nucleotide polymorphisms (SNP) in the CCL2 gene and prostate cancer clinicopathologic variables in a large hospital-based Caucasian patient cohort (N = 4,073).

RESULTS

Genetic variation at CCL2 is associated with markers of disease aggressiveness. Three SNPs, each in strong linkage disequilibrium, are associated with a higher (>7) biopsy Gleason score: CCL2 -1811 A/G, -2835 A/C, and +3726 T/C (P = 0.01, 0.03, and 0.04, respectively). The CCL2 -1811 G allele is additionally associated with advanced pathologic stages in patients who underwent radical prostatectomy (P = 0.04). In haplotype analysis, we found that the frequency of a common haplotype, H5, was higher among patients with D'Amico good risk features (P(permutation) = 0.04).

CONCLUSIONS

These results support the influence of CCL2 variants on prostate cancer development and progression.

CX3CR1 is required for airway inflammation by promoting T helper cell survival and maintenance in inflamed lung

Allergic asthma is a T helper type 2 (T(H)2)-dominated disease of the lung. In people with asthma, a fraction of CD4(+) T cells express the CX3CL1 receptor, CX3CR1, and CX3CL1 expression is increased in airway smooth muscle, lung endothelium and epithelium upon allergen challenge. Here we found that untreated CX3CR1-deficient mice or wild-type (WT) mice treated with CX3CR1-blocking reagents show reduced lung disease upon allergen sensitization and challenge. Transfer of WT CD4(+) T cells into CX3CR1-deficient mice restored the cardinal features of asthma, and CX3CR1-blocking reagents prevented airway inflammation in CX3CR1-deficient recipients injected with WT T(H)2 cells. We found that CX3CR1 signaling promoted T(H)2 survival in the inflamed lungs, and injection of B cell leukemia/lymphoma-2 protein (BCl-2)-transduced CX3CR1-deficient T(H)2 cells into CX3CR1-deficient mice restored asthma. CX3CR1-induced survival was also observed for T(H)1 cells upon airway inflammation but not under homeostatic conditions or upon peripheral inflammation. Therefore, CX3CR1 and CX3CL1 may represent attractive therapeutic targets in asthma.

Inter-Relationship between Chemokines and Mast Cells

The inflammatory response is mediated by immunological and chemotactic factors, proteins of the complement system, histamine, serotonin, arachidonic acid products and cytokines. All these compounds, including cytokines/chemokines, are major contributors to the symptoms of inflammation. Cytokines/chemokines, commonly referred to as “biological response modifiers”, are relatively new compounds for possible use in stimulation of the immune response, and display a number of overlapping abilities to stimulate cells of various lineages and differentiation stages; nonetheless, most of these compounds are potent inflammatory mediators. Mast cell mediators are either contained within secretory granules or can be synthesized de novo and can be released upon activation by either a massive degranulation, or by a selective release of specific molecules. These cells accumulate in the stroma of a variety of inflamed and transformed tissues in response to locally produced chemotactic factors for immune-cells, such as RANTES and MCP-1. Here we describe some connections between mast cells and chemokines.