CXCR3 as a molecular target in breast cancer metastasis: inhibition of tumor cell migration and promotion of host anti-tumor immunity

Comprehensive transcriptomic analysis of prostate cancer lung metastases

Metastatic prostate cancer (mPCa) is a widespread disease with high mortality. Unraveling molecular mechanisms of disease progression is of utmost importance. The microenvironment in visceral organs and the skeletal system is of particular interest as a harbinger of metastatic spread. Therefore, we performed a comprehensive transcriptomic analysis of prostate cancer lung metastases with a special focus on differentially expressed genes attributable to the microenvironment. Digital gene expression analysis using the NanoString nCounter analysis system was performed on formalin-fixed, paraffin-embedded (FFPE) tissue from prostate cancer (PCa) lung metastases (n = 24). Data were compared to gene expression data from primary PCa and PCa bone metastases. Bioinformatic analysis was performed using several publicly available tools. In comparison to prostate cancer bone metastases, 209 genes were significantly upregulated, and 100 genes were significantly downregulated in prostate cancer lung metastases. Among the up-regulated genes, the top 10 genes with the most significant P-value were HLA-DPB1, PTPRC, ITGB7, C3, CCL21, CCL5, ITGAM, SERPINA1, MFAP4, ARAP2 and among the down-regulated genes, the top 10 genes with the most significant P-value were FOXC2, TWIST1, CDK14, CHAD, IBSP, EPN3, VIT, HAPLN1, SLC44A4, TBX1. In PCa lung metastases genes associated with immunogenic responses were upregulated while genes associated with epithelial-mesenchymal transition were down-regulated. We also showed that CXCR3/CXCL10 axis plays a significant role in prostate cancer lung metastases in comparison to bone metastases. In this study, we comprehensively explored transcriptomic alterations in PCa lung metastases in comparison to primary PCa and PCa bone metastases. In PCa lung metastases genes associated with immunogenic responses are upregulated while genes associated with epithelial-mesenchymal transition are down-regulated. This points to a more immunogenic phenotype of PCa lung metastases thus potentially making patients more susceptible to immunotherapeutic approaches.

Systemic immunological profile of children with B-cell acute lymphoblastic leukemia: performance of cell populations and soluble mediators as serum biomarkers

Background

Children with B-cell acute lymphoblastic leukemia (B-ALL) have an immune imbalance that is marked by remodeling of the hematopoietic compartment, with effects on peripheral blood (PB). Although the bone marrow (BM) is the main maintenance site of malignancy, the frequency with which immune cells and molecules can be monitored is limited, thus the identification of biomarkers in PB becomes an alternative for monitoring the evolution of the disease.

Methods

Here, we characterize the systemic immunological profile in children undergoing treatment for B-ALL, and evaluate the performance of cell populations, chemokines and cytokines as potential biomarkers during clinical follow-up. For this purpose, PB samples from 20 patients with B-ALL were collected on diagnosis (D0) and during induction therapy (days 8, 15 and 35). In addition, samples from 28 children were used as a control group (CG). The cellular profile (NK and NKT-cells, Treg, CD3+ T, CD4+ T and CD8+ T cells) and soluble immunological mediators (CXCL8, CCL2, CXCL9, CCL5, CXCL10, IL-6, TNF, IFN-γ, IL-17A, IL- 4, IL-10 and IL-2) were evaluated via flow cytometry immunophenotyping and cytometric bead array assay.

Results

On D0, B-ALL patients showed reduction in the frequency of cell populations, except for CD4+ T and CD8+ T cells, which together with CCL2, CXCL9, CXCL10, IL-6 and IL-10 were elevated in relation to the patients of the CG. On D8 and D15, the patients presented a transition in the immunological profile. While, on D35, they already presented an opposite profile to D0, with an increase in NKT, CD3+ T, CD4+ T and Treg cells, along with CCL5, and a decrease in the levels of CXCL9, CXCL10 and IL-10, thus demonstrating that B-ALL patients present a complex and dynamic immune network during induction therapy. Furthermore, we identified that many immunological mediators could be used to classify the therapeutic response based on currently used parameters.

Conclusion

Finally, it is noted that the systemic immunological profile after remission induction still differs significantly when compared to the GC and that multiple immunological mediators performed well as serum biomarkers.

Evaluating differences in optical properties of indolent and aggressive murine breast tumors using quantitative diffuse reflectance spectroscopy

We used diffuse reflectance spectroscopy to quantify tissue absorption and scattering-based parameters in similarly sized tumors derived from a panel of four isogenic murine breast cancer cell lines (4T1, 4T07, 168FARN, 67NR) that are each capable of accomplishing different steps of the invasion-metastasis cascade. We found lower tissue scattering, increased hemoglobin concentration, and lower vascular oxygenation in indolent 67NR tumors incapable of metastasis compared with aggressive 4T1 tumors capable of metastasis. Supervised learning statistical approaches were able to accurately differentiate between tumor groups and classify tumors according to their ability to accomplish each step of the invasion-metastasis cascade. We investigated whether the inhibition of metastasis-promoting genes in the highly metastatic 4T1 tumors resulted in measurable optical changes that made these tumors similar to the indolent 67NR tumors. These results demonstrate the potential of diffuse reflectance spectroscopy to noninvasively evaluate tumor biology and discriminate between indolent and aggressive tumors.

A Network Landscape of HPVOPC Reveals Methylation Alterations as Significant Drivers of Gene Expression via an Immune-Mediated GPCR Signal

HPV-associated oropharynx carcinoma (HPVOPC) tumors have a relatively low mutational burden. Elucidating the relative contributions of other tumor alterations, such as DNA methylation alterations, alternative splicing events (ASE), and copy number variation (CNV), could provide a deeper understanding of carcinogenesis drivers in this disease. We applied network propagation analysis to multiple classes of tumor alterations in a discovery cohort of 46 primary HPVOPC tumors and 25 cancer-unaffected controls and validated our findings with TCGA data. We identified significant overlap between differential gene expression networks and all alteration classes, and this association was highest for methylation and lowest for CNV. Significant overlap was seen for gene clusters of G protein-coupled receptor (GPCR) pathways. HPV16-human protein interaction analysis identified an enriched cluster defined by an immune-mediated GPCR signal, including CXCR3 cytokines CXCL9, CXCL10, and CXCL11. CXCR3 was found to be expressed in primary HPVOPC, and scRNA-seq analysis demonstrated CXCR3 ligands to be highly expressed in M2 macrophages. In vivo models demonstrated decreased tumor growth with antagonism of the CXCR3 receptor in immunodeficient but not immunocompetent mice, suggesting that the CXCR3 axis can drive tumor proliferation in an autocrine fashion, but the effect is tempered by an intact immune system. In conclusion, methylation, ASE, and SNV alterations are highly associated with network gene expression changes in HPVOPC, suggesting that ASE and methylation alterations have an important role in driving the oncogenic phenotype. Network analysis identifies GPCR networks, specifically the CXCR3 chemokine axis, as modulators of tumor-immune interactions that may have proliferative effects on primary tumors as well as a role for immunosurveillance; however, CXCR3 inhibition should be used with caution, as these agents may both inhibit and stimulate tumor growth considering the competing effects of this cytokine axis. Further investigation is needed to explore opportunities for targeted therapy in this setting.

Single-cell data analysis of malignant epithelial cell heterogeneity in lung adenocarcinoma for patient classification and prognosis prediction

Lung cancer is one of the leading causes of cancer-related death. Most advanced lung adenocarcinoma (LUAD) patients have poor survival because of drug resistance and relapse. Neglecting intratumoral heterogeneity might be one of the reasons for treatment insensitivity, while single-cell RNA sequencing (scRNA-seq) technologies can provide transcriptome information at the single-cell level. Herein, we combined scRNA-seq and bulk RNA-seq data of LUAD and identified a novel cluster of malignant epithelial cells - KRT81+ malignant epithelial cells - associated with worse prognoses. Further analysis revealed that the hypoxia and EMT pathways of these cells were activated to predispose them to differentiate into metastatic lung adenocarcinoma cells. Finally, we also studied the role of these tumor cells in the immune microenvironment and their role in the classification and prognosis prediction of lung adenocarcinoma patients.

Targeting CXCL9/10/11-CXCR3 axis: an important component of tumor-promoting and antitumor immunity

Chemokines are chemotactic-competent molecules composed of a family of small cytokines, playing a key role in regulating tumor progression. The roles of chemokines in antitumor immune responses are of great interest. CXCL9, CXCL10, and CXCL11 are important members of chemokines. It has been widely investigated that these three chemokines can bind to their common receptor CXCR3 and regulate the differentiation, migration, and tumor infiltration of immune cells, directly or indirectly affecting tumor growth and metastasis. Here, we summarize the mechanism of how the CXCL9/10/11-CXCR3 axis affects the tumor microenvironment, and list the latest researches to find out how this axis predicts the prognosis of different cancers. In addition, immunotherapy improves the survival of tumor patients, but some patients show drug resistance. Studies have found that the regulation of CXCL9/10/11-CXCR3 on the tumor microenvironment is involved in the process of changing immunotherapy resistance. Here we also describe new approaches to restoring sensitivity to immune checkpoint inhibitors through the CXCL9/10/11-CXCR3 axis.

Metastasis prevention: How to catch metastatic seeds

Despite considerable advances in the evolution of anticancer therapies, metastasis still remains the main cause of cancer mortality. Therefore, current strategies for cancer cure should be redirected towards prevention of metastasis. Targeting metastatic pathways represents a promising therapeutic opportunity aimed at obstructing tumor cell dissemination and metastatic colonization. In this review, we focus on preclinical studies and clinical trials over the last five years that showed high efficacy in suppressing metastasis through targeting lymph node dissemination, tumor cell extravasation, reactive oxygen species, pre-metastatic niche, exosome machinery, and dormancy.

Role of interferon-gamma (IFN-γ) and IFN-γ receptor 1/2 (IFNγR1/2) in regulation of immunity, infection, and cancer development: IFN-γ-dependent or independent pathway

IFN-γ, a soluble cytokine being produced by T lymphocytes, macrophages, mucosal epithelial cells, or natural killer cells, is able to bind to the IFN-γ receptor (IFNγR) and in turn activate the Janus kinase (JAK)-signal transducer and transcription protein (STAT) pathway and induce expression of IFN-γ-stimulated genes. IFN-γ is critical for innate and adaptive immunity and aberrant IFN-γ expression and functions have been associated with different human diseases. However, the IFN-γ/IFNγR signaling could be a double-edged sword in cancer development because the tissue microenvironments could determine its anti- or pro-tumorigenic activities. The IFNγR protein consists of two IFNγR1 and IFNγR2 chains, subunits of which play different roles under certain conditions. This review assessed IFNγR polymorphisms, expression and functions in development and progression of various human diseases in an IFN-γ-dependent or independent manner. This review also discussed tumor microenvironment, microbial infection, and vital molecules in the IFN-γ upstream signaling that might regulate IFNγR expression, drug resistance, and druggable strategy, to provide evidence for further application of IFNγR.

Raman spectroscopy reveals phenotype switches in breast cancer metastasis

The accurate analytical characterization of metastatic phenotype at primary tumor diagnosis and its evolution with time are critical for controlling metastatic progression of cancer. Here, we report a label-free optical strategy using Raman spectroscopy and machine learning to identify distinct metastatic phenotypes observed in tumors formed by isogenic murine breast cancer cell lines of progressively increasing metastatic propensities. Methods: We employed the 4T1 isogenic panel of murine breast cancer cells to grow tumors of varying metastatic potential and acquired label-free spectra using a fiber probe-based portable Raman spectroscopy system. We used MCR-ALS and random forests classifiers to identify putative spectral markers and predict metastatic phenotype of tumors based on their optical spectra. We also used tumors derived from 4T1 cells silenced for the expression of TWIST, FOXC2 and CXCR3 genes to assess their metastatic phenotype based on their Raman spectra. Results: The MCR-ALS spectral decomposition showed consistent differences in the contribution of components that resembled collagen and lipids between the non-metastatic 67NR tumors and the metastatic tumors formed by FARN, 4T07, and 4T1 cells. Our Raman spectra-based random forest analysis provided evidence that machine learning models built on spectral data can allow the accurate identification of metastatic phenotype of independent test tumors. By silencing genes critical for metastasis in highly metastatic cell lines, we showed that the random forest classifiers provided predictions consistent with the observed phenotypic switch of the resultant tumors towards lower metastatic potential. Furthermore, the spectral assessment of lipid and collagen content of these tumors was consistent with the observed phenotypic switch. Conclusion: Overall, our findings indicate that Raman spectroscopy may offer a novel strategy to evaluate metastatic risk during primary tumor biopsies in clinical patients.

Identification of cell types in multiplexed in situ images by combining protein expression and spatial information using CELESTA

Advances in multiplexed in situ imaging are revealing important insights in spatial biology. However, cell type identification remains a major challenge in imaging analysis, with most existing methods involving substantial manual assessment and subjective decisions for thousands of cells. We developed an unsupervised machine learning algorithm, CELESTA, which identifies the cell type of each cell, individually, using the cell's marker expression profile and, when needed, its spatial information. We demonstrate the performance of CELESTA on multiplexed immunofluorescence images of colorectal cancer and head and neck squamous cell carcinoma (HNSCC). Using the cell types identified by CELESTA, we identify tissue architecture associated with lymph node metastasis in HNSCC, and validate our findings in an independent cohort. By coupling our spatial analysis with single-cell RNA-sequencing data on proximal sections of the same specimens, we identify cell-cell crosstalk associated with lymph node metastasis, demonstrating the power of CELESTA to facilitate identification of clinically relevant interactions.

Combination of IDO1high and CCL19low expression in the tumor tissue reduces survival in HPV positive cervical cancer

The over expression of Indoleamine 2, 3-Dioxygenase (IDO1), an immune checkpoint inhibitor, is well known in cervical cancer. However, its association with chemokine signals promoting cellular infiltration in the cervical tumor microenvironment, is unknown. In the current study, we evaluated the expression and enzymatic activity of IDO1. We also profiled the expression of chemokine ligand-receptors- CCR4-CCL22, CXCR3-CXCL10, CXCR4-CXCL12, and CCR7-CCL19 using immunohistochemistry (IHC), and studied their association with IDO1, statistically. After getting an informed consent, punch biopsy samples were obtained from 105 patients diagnosed with cervical cancer. HPV typing by Sanger sequencing, realtime PCR for quantifying IDO1 mRNA expression, HPLC for determining the K/T ratio and IHC for all the above chemokine receptor-ligand pairs along with IDO1 were performed. We found a significant increase in the expression of IDO1 and K/T levels in early and locally advanced stages when compared to Stage IV disease. Among the chemokine ligand -receptor pairs profiled, we found that high CCL19 marker expression was a good prognostic indicator of patients' disease-free (p = 0.013) and overall survival (p = 0.043). Although we could not identify IDO1 as an independent prognostic factor, we found that high levels of IDO1 expression may further reduce survival outcomes in patients with low CCL19 expression. This could be vital for designing immuno therapeutic interventions targeting IDO1.

Contribution of CXCR3-mediated signaling in the metastatic cascade of solid malignancies

Metastasis is a significant cause of the mortality resulting from solid malignancies. The process of metastasis is complex and is regulated by numerous cancer cell-intrinsic and -extrinsic factors. CXCR3 is a chemokine receptor that is frequently expressed by cancer cells, endothelial cells and immune cells. CXCR3A signaling in cancer cells tends to promote the invasive and migratory phenotype of cancer cells. Indirectly, CXCR3 modulates the anti-tumor immune response resulting in variable effects that can permit or inhibit metastatic progression. Finally, the activity of CXCR3B in endothelial cells is generally angiostatic, which limits the access of cancer cells to key conduits to secondary sites. However, the interaction of these activities within a tumor and the presence of opposing CXCR3 splice variants clouds the picture of the role of CXCR3 in metastasis. Consequently, thorough analysis of the contributions of CXCR3 to cancer metastasis is necessary. This review is an in-depth examination of the involvement of CXCR3 in the metastatic process of solid malignancies.

Wrinkle in the plan: miR-34a-5p impacts chemokine signaling by modulating CXCL10/CXCL11/CXCR3-axis in CD4+, CD8+ T cells, and M1 macrophages

BACKGROUND

In 2016 the first-in-human phase I study of a miRNA-based cancer therapy with a liposomal mimic of microRNA-34a-5p (miR-34a-5p) was closed due to five immune related serious adverse events (SAEs) resulting in four patient deaths. For future applications of miRNA mimics in cancer therapy it is mandatory to unravel the miRNA effects both on the tumor tissue and on immune cells. Here, we set out to analyze the impact of miR-34a-5p over-expression on the CXCL10/CXCL11/CXCR3 axis, which is central for the development of an effective cancer control.

METHODS

We performed a whole genome expression analysis of miR-34a-5p transfected M1 macrophages followed by an over-representation and a protein-protein network analysis. In-silico miRNA target prediction and dual luciferase assays were used for target identification and verification. Target genes involved in chemokine signaling were functionally analyzed in M1 macrophages, CD4⁺ and CD8⁺ T cells.

RESULTS

A whole genome expression analysis of M1 macrophages with induced miR-34a-5p over-expression revealed an interaction network of downregulated target mRNAs including CXCL10 and CXCL11. In-silico target prediction in combination with dual luciferase assays identified direct binding of miR-34a-5p to the 3'UTRs of CXCL10 and CXCL11. Decreased CXCL10 and CXCL11 secretion was shown on the endogenous protein level and in the supernatant of miR-34a-5p transfected and activated M1 macrophages. To complete the analysis of the CXCL10/CXCL11/CXCR3 axis, we activated miR-34a-5p transfected CD4⁺ and CD8⁺ T cells by PMA/Ionomycin and found reduced levels of endogenous CXCR3 and CXCR3 on the cell surface.

CONCLUSIONS

MiR-34a-5p mimic administered by intravenous administration will likely not only be up-taken by the tumor cells but also by the immune cells. Our results indicate that miR-34a-5p over-expression leads in M1 macrophages to a reduced secretion of CXCL10 and CXCL11 chemokines and in CD4⁺ and CD8⁺ T cells to a reduced expression of CXCR3. As a result, less immune cells will be attracted to the tumor site. Furthermore, high levels of miR-34a-5p in naive CD4⁺ T cells can in turn hinder Th1 cell polarization through the downregulation of CXCR3 leading to a less pronounced activation of cytotoxic T lymphocytes, natural killer, and natural killer T cells and possibly contributing to lymphocytopenia.

Chemokine Receptor Antagonists: Role in Oncology

PURPOSE OF REVIEW

To evaluate the clinical potential of chemokine receptor antagonists for the treatment of patients with cancer.

RECENT FINDINGS

Chemokine receptors and their ligands can have a significant impact on the infiltration of cells into the tumor microenvironment. The receptors are increasingly being investigated as targets for the treatment of cancers. Recent studies are demonstrating the promise of chemokine receptor antagonists in this setting. There are many chemokine receptors, and each can have different functions depending on the cellular context. Targeting chemokine receptors is a promising strategy in both pre-clinical research and clinical trials. Inhibiting chemokine receptors that either recruit suppressive cells or improve cancer mobility and viability while sparing those necessary for proper immune trafficking may prove to dramatically improve treatment responses. Further research in this area is warranted and has the potential to dramatically improve patient outcomes.

Imbalance of Chemokines and Cytokines in the Bone Marrow Microenvironment of Children with B-Cell Acute Lymphoblastic Leukemia

In the hematopoietic microenvironment, leukemic cells secrete factors that imbalanced chemokine and cytokine production. However, the network of soluble immunological molecules in the bone marrow microenvironment of acute lymphoblastic leukemia (ALL) remains underexplored. Herein, we evaluated the levels of the immunological molecules (CXCL8, CCL2, CXCL9, CCL5, CXCL10, IL-6, TNF, IFN-γ, IL-17A, IL-4, IL-10, and IL-2) in the bone marrow plasma of 47 recently diagnosed B-cell acute lymphoblastic leukemia (B-ALL) patients during induction therapy using cytometric beads arrays. The results demonstrated that B-ALL patients showed high levels of CXCL9, CXCL10, IL-6, and IL-10 at the time of diagnosis, while at the end of induction therapy, a decrease in the levels of these immunological molecules and an increase in CCL5, IFN-γ, and IL-17A levels were observed. These findings indicate that B-ALL patients have an imbalance in chemokines and cytokines in the bone marrow microenvironment that contributes to suppressing the immune response. This immune imbalance may be associated with the presence of leukemic cells since, at the end of the induction therapy, with the elimination and reduction to residual cells, the proinflammatory profile is reestablished, characterized by an increase in the cytokines of the Th1 and Th17 profiles.

MLKL in cancer: more than a necroptosis regulator

Mixed lineage kinase domain-like protein (MLKL) emerged as executioner of necroptosis, a RIPK3-dependent form of regulated necrosis. Cell death evasion is one of the hallmarks of cancer. Besides apoptosis, some cancers suppress necroptosis-associated mechanisms by for example epigenetic silencing of RIPK3 expression. Conversely, necroptosis-elicited inflammation by cancer cells can fuel tumor growth. Recently, necroptosis-independent functions of MLKL were unraveled in receptor internalization, ligand-receptor degradation, endosomal trafficking, extracellular vesicle formation, autophagy, nuclear functions, axon repair, neutrophil extracellular trap (NET) formation, and inflammasome regulation. Little is known about the precise role of MLKL in cancer and whether some of these functions are involved in cancer development and metastasis. Here, we discuss current knowledge and controversies on MLKL, its structure, necroptosis-independent functions, expression, mutations, and its potential role as a pro- or anti-cancerous factor. Analysis of MLKL expression patterns reveals that MLKL is upregulated by type I/II interferon, conditions of inflammation, and tissue injury. Overall, MLKL may affect cancer development and metastasis through necroptosis-dependent and -independent functions.

Claudin-Low Breast Cancer Inflammatory Signatures Support Polarization of M1-Like Macrophages with Protumoral Activity

We previously reported that triple-negative breast cancer (BRCA) cells overexpress the cytokines GM-CSF, G-CSF, MCP-1, and RANTES, and when monocytes were 3-D co-cultured with them, M1-like macrophages were generated with the ability to induce aggressive features in luminal BRCA cell lines. These include upregulation of mesenchymal and stemness markers and invasion. In this study, we stimulated peripheral blood monocytes with the four cytokines and confirmed their capacity to generate protumoral M1-like macrophages. Using the METABRIC BRCA database, we observed that GM-CSF, MCP-1, and RANTES are associated with triple-negative BRCA and reduced overall survival, particularly in patients under 55 years of age. We propose an extended M1-like macrophage proinflammatory signature connected with these three cytokines. We found that the extended M1-like macrophage signature coexists with monocyte/macrophage, Th1 immune response, and immunosuppressive signatures, and all are enriched in claudin-low BRCA samples, and correlate with reduced patient overall survival. Furthermore, we observed that all these signatures are also present in mesenchymal carcinomas of the colon (COAD) and bladder (BLCA). The claudin-low tumor subtype has an adverse clinical outcome and remains poorly understood. This study places M1 macrophages as potential protumoral drivers in already established cancers, and as potential contributors to claudin-low aggressiveness and poor prognosis.

Systemic tumour suppression via the preferential accumulation of erythrocyte-anchored chemokine-encapsulating nanoparticles in lung metastases

Eliciting immune responses against primary tumours is hampered by their immunosuppressive microenvironment and by the greater inaccessibility of deeper intratumoural cells. However, metastatic tumour cells are exposed to highly perfused and immunoactive organs, such as the lungs. Here, by taking advantage of the preferential colocalization of intravenously administered erythrocytes with metastases in the lungs, we show that treatment with chemokine-encapsulating nanoparticles that are non-covalently anchored onto the surface of injected erythrocytes results in local and systemic tumour suppression in mouse models of lung metastasis. Such erythrocyte-anchored systemic immunotherapy led to the infiltration of effector immune cells into the lungs, in situ immunization without the need for exogenous antigens, inhibition of the progression of lung metastasis, and significantly extended animal survival and systemic immunity that suppressed the growth of distant tumours after rechallenge. Erythrocyte-mediated systemic immunotherapy may represent a general and potent strategy for cancer vaccination.

In-Depth Characterization of Stromal Cells within the Tumor Microenvironment Yields Novel Therapeutic Targets

Simple Summary

This up-to-date and in-depth review describes fibroblast-derived cells and their role within the tumor microenvironment for tumor progression. Moreover, targets for future antitumor therapies are summarized and potential aspects for future translational research are outlined. Furthermore, this review discusses the challenges and possible obstacles related to certain treatment targets.

Abstract

Cells within the tumor stroma are essential for tumor progression. In particular, cancer-associated fibroblasts (CAF) and CAF precursor cells (resident fibroblasts and mesenchymal stromal cells) are responsible for the formation of the extracellular matrix in tumor tissue. Consequently, CAFs directly and indirectly mediate inflammation, metastasis, immunomodulation, angiogenesis, and the development of tumor chemoresistance, which is orchestrated by complex intercellular cytokine-mediated crosstalk. CAFs represent a strategic target in antitumor therapy but their heterogeneity hinders effective treatment regimes. In-depth understanding of CAF subpopulations and knowledge of specific functions in tumor progression will ultimately result in more specific and effective cancer treatments. This review provides a detailed description of CAFs and CAF precursor cells and summarizes possible treatment strategies as well as molecular targets of these cells in antitumor therapies.

Tumor inhibition or tumor promotion? The duplicity of CXCR3 in cancer

Tumor tissue includes cancer cells and normal stromal cells such as vascular endothelial cells, connective tissue cells (cancer associated fibroblast, mesenchymal stem cell), and immune cells (tumor-infiltrating lymphocytes or TIL, dendritic cells, eosinophils, basophils, mast cells, tumor-associated macrophages or TAM, myeloid-derived suppressor cells or MDSC). Anti-tumor activity is mainly mediated by infiltration of NK cells, Th1 and CD8⁺ T cells, and correlates with expression of NK cell and T cell attracting chemokines. Nevertheless, cancer cells hijack tissue homeostasis through secretion of cytokines and chemokines that mediate not only the induction of an inflamed status that supports cancer cell survival and growth, but also the recruitment and/or activation of immune suppressive cells. CXCL9, CXCL10, and CXCL11 are known for their tumor-inhibiting properties, but their overexpression in several hematologic and solid tumors correlates with disease severity, suggesting a role in tumor promotion. The dichotomous nature of CXCR3 ligands activity mainly depends on several molecular mechanisms induced by cancer cells themselves able to divert immune responses and to alter the whole local environment. A deep understanding of the nature of such phenomenon may provide a rationale to build up a CXCR3/ligand axis targeting strategy. In this review, we will discuss the role of CXCR3 in cancer progression and in regulation of anti-tumor immune response and immunotherapy.

Expression and role of MIG/CXCR3 axis in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a unique subtype of B-cell non-Hodgkin lymphoma with a generally aggressive and heterogeneous clinical course. Chemokines are one of the complex components in the tumor microenvironment (TME), and they play a vital role in tumor progression and metastasis. There is no information about the monokine induced by gamma interferon (MIG)/CXC chemokine receptor 3 (CXCR3) axis in patients with MCL. In the present study, we discovered that CXCR3 was highly expressed in MCL tissues and some cell lines including Maver, Z138, and Jeko-1, and significantly associated with clinical factors reflecting high tumor burden in MCL patients. Moreover, elevated serum MIG at diagnosis showed a close relationship with advanced disease and poor prognosis in MCL patients. Additionally, the role of CXCR3 in promoting the proliferation and inhibiting the apoptosis of primary MCL cells and Jeko-1 cells was validated by in vitro experiments. Further research indicated that the MIG/CXCR3 axis mediated MCL cell migration to the TME through the PI3K/AKT signaling pathway. Therefore, the MIG/CXCR3 axis might be a potential target with fewer off-target side effects than other targets in MCL.

Integrated analysis of tumor mutation burden and immune infiltrates in endometrial cancer

To explore the prognostic value of tumor mutation burden (TMB) and its correlation with immune infiltrates in endometrial cancer. Transcriptome and somatic mutation profiles of Uterine Corpus Endometrial Carcinoma (UCEC) were downloaded from TCGA database. Somatic mutations were analyzed by "maftools" and visualized in waterfall plot. We calculated TMB of each patients and divided all patients into the high-TMB group and the low-TMB group by the median threshold. Survival analysis and Wilcoxon test were used to investigate the prognostic value of TMB and its association with clinical variables. Differentially expressed genes (DEGs) were identified in 2 TMN groups and functional analysis was performed to find out significant biological pathways. A TMB-related signature was conducted by multivariate analysis, receiver operating characteristic (ROC) curve was performed to predict accuracy of the model, meanwhile, a validation cohort from Fudan University Shanghai Cancer Center (FUSCC) was obtained to verify the signature. Then we estimated association between TMB and immune infiltrates by CIBERSORT algorithm and figured out prognostic immune cells of UCEC in TIMER database. Total 575 samples including 25 normal tissues and 552 tumor samples were enrolled from TCGA database. PTEN mutations accounted for the most and single nucleotide polymorphism and C>T transitions were most frequent forms of somatic mutations in UCEC. The low-TMB group possessed worse survival than the high-TMB group (P = 0.004). DEGs in 2 TMB groups were mostly enriched in adaptive immune response and immunoglobulin/immune receptor component. A TMB-related signature consisting of GFAP, EDN3, CXCR3, PLXNA4, SST presented good predictability with area under the curve (AUC) = 0.686. In FUSCC validation cohort, the high-risk group possessed worse survival outcome than the low-risk group (P = 0.015). Immune infiltrates was correlated to survival in UCEC and low TMB were associated with less immune infiltrates, which suggested poor immune response. TMB was not only related to overall survival but also immune infiltrates in UCEC. The TMB-related signature (GFAP, EDN3, CXCR3, PLXNA4, SST) had good predictability for overall survival in endometrial cancer. Our study might have some merits in elucidating potential mechanism of TMB and immune infiltrates in UCEC and providing guidance of immunotherapy for endometrial cancer.

Role of Chemokines in the Biology of Cholangiocarcinoma

Cholangiocarcinoma (CCA), a heterogeneous tumor with poor prognosis, can arise at any level in the biliary tree. It may derive from epithelial cells in the biliary tracts and peribiliary glands and possibly from progenitor cells or even hepatocytes. Several risk factors are responsible for CCA onset, however an inflammatory milieu nearby the biliary tree represents the most common condition favoring CCA development. Chemokines play a key role in driving the immunological response upon liver injury and may sustain tumor initiation and development. Chemokine receptor-dependent pathways influence the interplay among various cellular components, resulting in remodeling of the hepatic microenvironment towards a pro-inflammatory, pro-fibrogenic, pro-angiogenic and pre-neoplastic setting. Moreover, once tumor develops, chemokine signaling may influence its progression. Here we review the role of chemokines in the regulation of CCA development and progression, and the modulation of angiogenesis, metastasis and immune control. The potential role of chemokines and their receptors as possible biomarkers and/or therapeutic targets for hepatobiliary cancer is also discussed.

Chemokines in bone-metastatic breast cancer: Therapeutic opportunities

Due to non-response to chemotherapy, incomplete surgical resection, and resistance to checkpoint inhibitors, breast cancer with bone metastasis is notoriously difficult to cure. Therefore, the development of novel, efficient strategies to tackle bone metastasis of breast cancer is urgently needed. Chemokines, which induce directed migration of immune cells and act as guide molecules between diverse cells and tissues, are small proteins indispensable in immunity. These complex chemokine networks play pro-tumor roles or anti-tumor roles when produced by breast cancer cells in the tumor microenvironment. Additionally, chemokines have diverse roles when secreted by various immune cells in the tumor microenvironment of breast cancer, which can be roughly divided into immunosuppressive effects and immunostimulatory effects. Recently, targeting chemokine networks has been shown to have potential for use in treatment of metastatic malignancies, including bone-metastatic breast cancer. In this review, we focus on the role of chemokines networks in the biology of breast cancer and metastasis to the bone. We also discuss the therapeutic opportunities and future prospects of targeting chemokine networks, in combination with other current standard therapies, for the treatment of bone-metastatic breast cancer.

CXCR3 antagonist AMG487 inhibits glucocorticoid-induced tumor necrosis factor-receptor-related protein and inflammatory mediators in CD45 expressing cells in collagen-induced arthritis mouse model

Rheumatoid arthritis (RA) is an autoimmune disease classified by uncontrolled joint inflammation leading to the destruction of both cartilage and joints. Despite progress made in RA treatment in the past decade, new drugs with high efficacy and fewer long-term adverse effects are still needed; thus, safe anti-inflammatory therapies for RA are urgently needed. Previous results demonstrated that the CXCR3 antagonist is an extremely attractive therapeutic target for the treatment of several autoimmune diseases, suggesting that it might have an inhibitory effect on RA. In this study, we investigated the effect of AMG487, a selective CXCR3 antagonist, on collagen-induced arthritis (CIA) in mice and evaluated its potential therapeutic mechanism.Following induction of CIA, mice were treated with AMG487 (5 mg/kg, intraperitoneally), to investigate their protective effects against CIA. CD4, CD25, CCR6, IL-9, NF-κB, IL-6, IL-17A, IL-21, STAT6 and Foxp3 expressing GITR⁺ and CD45⁺ cells were measured in the spleen using flow cytometry to assess anti-inflammatory effects of AMG487. The mRNA and protein expression of GITR, CCR6, IL-9, and IL-21 were measured using quantitative real-time PCR and western blot analysis in knee tissue. AMG487 significantly alleviated joint inflammation by decreasing GITR⁺CD25⁺, GITR⁺CD45⁺, GITR⁺IL-9⁺, GITR⁺NF-κB⁺ CD45⁺CD4⁺, CD45⁺CCR6⁺, CD45⁺IL-6⁺ cells, CD45⁺IL-17A⁺, and CD45⁺IL-21⁺, and increasing GITR⁺Foxp3⁺ and GITR⁺STAT6⁺ cells. There was a significant decrease in mRNA and protein expression of GITR, CD4, CCR6, IL-6, IL-9, and IL-21 in knee tissue of CIA mice. This study demonstrates that AMG487 has a potential therapeutic effect on RA and could explore novel anti-inflammatory therapies for its treatment.

The Expression of Selected Factors Related to T Lymphocyte Activity in Canine Mammary Tumors

Crosstalk between neoplastic and immune cells in the tumor microenvironment (TME) influences the progression of disease in human and canine cancer patients. Given that canine mammary tumors are a useful model to study breast cancer biology, we aimed to evaluate the expression of genes associated with T lymphocyte activity in benign, malignant, and metastatic canine mammary tumors. Interestingly, metastatic tumors exhibit increased expression of CXCR3, CCR2, IL-4, IL-12p40, and IL-17. In particular, we focused on IL-17, a key interleukin associated with the Th17 lymphocyte phenotype. Th17 cells have been shown to play a contradictory role in tumor immunity. Although IL-17 showed a high expression in the metastatic tumors, the expression of RORγt, a crucial transcription factor for Th17 differentiation was barely detected. We further investigated IL-17 expression using immunohistochemistry, through which we confirmed the increased expression of this interleukin in malignant and metastatic mammary tumors. Finally, we compared the plasma levels of IL-17 in healthy and malignant mammary tumor-bearing dogs using ELISA but found no differences between the groups. Our data indicate that the IL-17 in metastatic tumors may be produced by other cell types, but not by Th17 lymphocytes. Overall, our results broaden the available knowledge on the interactions in canine mammary tumors and provide insight into the development of new therapeutic strategies, with potential benefits for human immune oncology.

DNA methylation landscape of triple-negative ductal carcinoma in situ (DCIS) progressing to the invasive stage in canine breast cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer unresponsive to traditional receptor-targeted treatments, leading to a disproportionate number of deaths. Invasive breast cancer is believed to evolve from non-invasive ductal carcinoma in situ (DCIS). Detection of triple-negative DCIS (TN-DCIS) is challenging, therefore strategies to study molecular events governing progression of pre-invasive TN-DCIS to invasive TNBC are needed. Here, we study a canine TN-DCIS progression and investigate the DNA methylation landscape of normal breast tissue, atypical ductal hyperplasia (ADH), DCIS and invasive breast cancer. We report hypo- and hypermethylation of genes within functional categories related to cancer such as transcriptional regulation, apoptosis, signal transduction, and cell migration. DNA methylation changes associated with cancer-related genes become more pronounced at invasive breast cancer stage. Importantly, we identify invasive-only and DCIS-specific DNA methylation alterations that could potentially determine which lesions progress to invasive cancer and which could remain as pre-invasive DCIS. Changes in DNA methylation during TN-DCIS progression in this canine model correspond with gene expression patterns in human breast tissues. This study provides evidence for utilizing methylation status of gene candidates to define late-stage (DCIS and invasive), invasive stage only or DCIS stage only of TN-DCIS progression.

Detecting heterogeneity in and between breast cancer cell lines

Background

Cellular heterogeneity in tumor cells is a well-established phenomenon. Genetic and phenotypic cell-to-cell variability have been observed in numerous studies both within the same type of cancer cells and across different types of cancers. Another known fact for metastatic tumor cells is that they tend to be softer than their normal or non-metastatic counterparts. However, the heterogeneity of mechanical properties in tumor cells are not widely studied.

Results

Here we analyzed single-cell optical stretcher data with machine learning algorithms on three different breast tumor cell lines and show that similar heterogeneity can also be seen in mechanical properties of cells both within and between breast tumor cell lines. We identified two clusters within MDA-MB-231 cells, with cells in one cluster being softer than in the other. In addition, we show that MDA-MB-231 cells and MDA-MB-436 cells which are both epithelial breast cancer cell lines with a mesenchymal-like phenotype derived from metastatic cancers are mechanically more different from each other than from non-malignant epithelial MCF-10A cells.

Conclusion

Since stiffness of tumor cells can be an indicator of metastatic potential, this result suggests that metastatic abilities could vary within the same monoclonal tumor cell line.

CXC Chemokine Receptors in the Tumor Microenvironment and an Update of Antagonist Development

Chemokine receptors, a diverse group within the seven-transmembrane G protein-coupled receptor superfamily, are frequently overexpressed in malignant tumors. Ligand binding activates multiple downstream signal transduction cascades that drive tumor growth and metastasis, resulting in poor clinical outcome. These receptors are thus considered promising targets for anti-tumor therapy. This article reviews recent studies on the expression and function of CXC chemokine receptors in various tumor microenvironments and recent developments in cancer therapy using CXC chemokine receptor antagonists.

Effects of Tobacco Smoking on the Tumor Immune Microenvironment in Head and Neck Squamous Cell Carcinoma

PURPOSE

Patients with head and neck squamous cell carcinoma (HNSCC) who actively smoke during treatment have worse survival compared with never-smokers and former-smokers. We hypothesize the poor prognosis in tobacco smokers with HNSCC is, at least in part, due to ongoing suppression of immune response. We characterized the tumor immune microenvironment (TIM) of HNSCC in a retrospective cohort of 177 current, former, and never smokers.

EXPERIMENTAL DESIGN

Tumor specimens were subjected to analysis of CD3, CD8, FOXP3, PD-1, PD-L1, and pancytokeratin by multiplex immunofluorescence, whole-exome sequencing, and RNA sequencing. Immune markers were measured in tumor core, tumor margin, and stroma.

RESULTS

Our data indicate that current smokers have significantly lower numbers of CD8⁺ cytotoxic T cells and PD-L1⁺ cells in the TIM compared with never- and former-smokers. While tumor mutation burden and mutant allele tumor heterogeneity score do not associate with smoking status, gene-set enrichment analyses reveal significant suppression of IFNα and IFNγ response pathways in current smokers. Gene expression of canonical IFN response chemokines, CXCL9, CXCL10, and CXCL11, are lower in current smokers than in former smokers, suggesting a mechanism for the decreased immune cell migration to tumor sites.

CONCLUSIONS

These results suggest active tobacco use in HNSCC has an immunosuppressive effect through inhibition of tumor infiltration of cytotoxic T cells, likely as a result of suppression of IFN response pathways. Our study highlights the importance of understanding the interaction between smoking and TIM in light of emerging immune modulators for cancer management.

CXCL12-CXCL4 heterodimerization prevents CXCL12-driven breast cancer cell migration

Despite improvements in cancer early detection and treatment, metastatic breast cancer remains deadly. Current therapeutic approaches have very limited efficacy in patients with triple negative breast cancer. Among the many mechanisms associated that contribute to cancer progression, signaling through the CXCL12-CXCR4 is an essential step in cancer cell migration. We previously demonstrated the formation of CXCL12-CXCL4 heterodimers (Carlson et al., 2013). Here, we investigated whether CXCL12-CXCL4 heterodimers alter tumor cell migration. CXCL12 alone dose-dependently promoted the MDA-MB 231 cell migration (p < .05), which could be prevented by blocking the CXCR4 receptor. The addition of CXCL4 inhibited the CXCL12-induced cell migration (p < .05). Using NMR spectroscopy, we identified the CXCL4-CXCL12 binding interface. Moreover, we generated a CXCL4-derived peptide homolog of the binding interface that mimicked the activity of native CXCL4 protein. These results confirm the formation of CXCL12-CXCL4 heterodimers and their inhibitory effects on the migration of breast tumors cells. These findings suggest that specific peptides mimicking heterodimerization of CXCL12 might prevent breast cancer cell migration.

CXCR4 and CXCR3 are two distinct prognostic biomarkers in breast cancer: Database mining for CXCR family members

CXC chemokine receptors (CXCRs) and chemokines are involved in tissue development and homeostasis, including in cancer development and progression. To date, seven CXCRs have been identified. However, the expression of CXCRs and their influence on the occurrence and development of breast cancer (BC) requires further investigation. In the present study, mRNA expression levels of the seven CXCRs were compared between normal tissues and several cancer types using the Oncomine database. Highly expressed CXCRs were selected and the expression levels of these CXCRs were examined in different subtypes of BC using the Gene Expression-Based Outcome for Breast Cancer database. Finally, the prognostic value of these CXCRs was examined using Kaplan-Meier plotter. It was found that, compared with normal controls, transcripts of CXCR4 and CXCR3 were significantly overexpressed in BC samples compared with other CXCRs. Survival analysis showed that high expression of CXCR4 promoted the recurrence of BC but had no impact on overall survival (OS), while a high level of CXCR3 transcript expression was significantly associated with increased survival in patients with BC. With regards to different subtypes of BC, the present study revealed that high CXCR4 transcript expression was significantly associated with both longer relapse-free survival and OS only in basal-like BC. Furthermore, CXCR4 promoted chemosensitivity in patients with basal-like BC and induced resistance against endocrine therapy for patients with luminal A BC. Thus, CXCR4 and CXCR3 are two distinct prognostic biomarkers and further studies are required.

The Chemokine Receptor CXCR3 Isoform B Drives Breast Cancer Stem Cells

We are seeking to identify molecular targets that are relevant to breast cancer cells with stem-like properties. There is growing evidence that cancer stem cells (CSCs) are supported by inflammatory mediators expressed in the tumor microenvironment. The chemokine receptor CXCR3 binds the interferon-γ-inducible, ELR-negative CXC chemokines CXCL9, CXCL10, and CXCL11 and malignant cells have co-opted this receptor to promote tumor cell migration and invasion. There are 2 major isoforms of CXCR3: CXCR3A and CXCR3B. The latter is generated from alternative splicing and results in a protein with a longer N-terminal domain. CXCR3 isoform A is generally considered to play a major role in tumor metastasis. When the entire tumor cell population is examined, CXCR3 isoform B is usually detected at much lower levels than CXCR3A and for this, and other reasons, was not considered to drive tumor progression. We have shown that CXCR3B is significantly upregulated in the subpopulation of breast CSCs in comparison with the bulk tumor cell population in 3 independent breast cancer cell lines (MDA-MB-231, SUM159, and T47D). Modulation of CXCR3B levels by knock in strategies increases CSC populations identified by aldehyde dehydrogenase activity or CD44⁺CD24⁻ phenotype as well as tumorsphere-forming capacity. The reverse is seen when CXCR3B is gene-silenced. CXCL11 and CXCL10 directly induce CSC. We also report that novel CXCR3 allosteric modulators BD064 and BD103 prevent the induction of CSCs. BD103 inhibited experimental metastasis. This protective effect is associated with the reversal of CXCR3 ligand-mediated activation of STAT3, ERK1/2, CREB, and NOTCH1 pathways. We propose that CXCR3B, expressed on CSC, should be explored further as a novel therapeutic target.

Identification of Alternatively-Activated Pathways between Primary Breast Cancer and Liver Metastatic Cancer Using Microarray Data

Alternatively-activated pathways have been observed in biological experiments in cancer studies, but the concept had not been fully explored in computational cancer system biology. Therefore, an alternatively-activated pathway identification method was proposed and applied to primary breast cancer and breast cancer liver metastasis research using microarray data. Interestingly, the results show that cytokine-cytokine receptor interaction and calcium signaling were significantly enriched under both conditions. TGF beta signaling was found to be the hub in network topology analysis. In total, three types of alternatively-activated pathways were recognized. In the cytokine-cytokine receptor interaction pathway, four active alteration patterns in gene pairs were noticed. Thirteen cytokine-cytokine receptor pairs with inverse activity changes of both genes were verified by the literature. The second type was that some sub-pathways were active under only one condition. For the third type, nodes were significantly active in both conditions, but with different active genes. In the calcium signaling and TGF beta signaling pathways, node E2F5 and E2F4 were significantly active in primary breast cancer and metastasis, respectively. Overall, our study demonstrated the first time using microarray data to identify alternatively-activated pathways in breast cancer liver metastasis. The results showed that the proposed method was valid and effective, which could be helpful for future research for understanding the mechanism of breast cancer metastasis.

The Distinct Roles of CXCR3 Variants and Their Ligands in the Tumor Microenvironment

First thought to orchestrate exclusively leukocyte trafficking, chemokines are now acknowledged for their multiple roles in the regulation of cell proliferation, differentiation, and survival. Dysregulation of their normal functions contributes to various pathologies, including inflammatory diseases and cancer. The two chemokine receptor 3 variants CXCR3-A and CXCR3-B, together with their cognate chemokines (CXCL11, CXCL10, CXCL9, CXCL4, and CXCL4L1), are involved in the control but also in the development of many tumors. CXCR3-A drives the infiltration of leukocytes to the tumor bed to modulate tumor progression (paracrine axis). Conversely, tumor-driven changes in the expression of the CXCR3 variants and their ligands promote cancer progression (autocrine axis). This review summarizes the anti- and pro-tumoral activities of the CXCR3 variants and their associated chemokines with a focus on the understanding of their distinct biological roles in the tumor microenvironment.

Lymph-circulating tumor cells show distinct properties to blood-circulating tumor cells and are efficient metastatic precursors

The leading cause of breast cancer-associated death is metastasis. In 80% of solid tumors, metastasis via the lymphatic system precedes metastasis via the vascular system. However, the molecular properties of tumor cells as they exit the primary tumor into the afferent lymphatics en route to the sentinel lymph nodes (SLNs) are not yet known. Here, we developed an innovative technique that enables the collection of lymph and lymph-circulating tumor cells (LCTCs) en route to the SLN in an immunocompetent animal model of breast cancer metastasis. We found that the gene and protein expression profiles of LCTCs and blood-circulating tumor cells (BCTCs) as they exit the primary tumor are similar, but distinct from those of primary tumors and lymph node metastases (LNMs). LCTCs, but not BCTCs, exist in clusters, display a hybrid epithelial/mesenchymal phenotype and cancer stem cell-like properties, and are efficient metastatic precursors. These results demonstrate that tumor cells that metastasize through the lymphatic system are different from those spread by blood circulation. Understanding the relative contribution of these cells to overall peripheral blood-circulating tumor cells is important for cancer therapy. Whether these two types of cell occur in cancer patients remains to be determined.

The Role of CXCR3 in Neurological Diseases

BACKGROUND

Neurological diseases have become an obvious challenge due to insufficient therapeutic intervention. Therefore, novel drugs for various neurological disorders are in desperate need. Recently, compelling evidence has demonstrated that chemokine receptor CXCR3, which is a G protein-coupled receptor in the CXC chemokine receptor family, may play a pivotal role in the development of neurological diseases. The aim of this review is to provide evidence for the potential of CXCR3 as a therapeutic target for neurological diseases.

METHODS

English journal articles that focused on the invovlement of CXCR3 in neurological diseases were searched via PubMed up to May 2017. Moreover, reference lists from identified articles were included for overviews.

RESULTS

The expression level of CXCR3 in T cells was significantly elevated in several neurological diseases, including multiple sclerosis (MS), glioma, Alzheimer's disease (AD), chronic pain, human T-lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and bipolar disorder. CXCR3 antagonists showed therapeutic effects in these neurological diseases.

CONCLUSION

These studies provided hard evidence that CXCR3 plays a vital role in the pathogenesis of MS, glioma, AD, chronic pain, HAM/TSP and bipolar disorder. CXCR3 is a crucial molecule in neuroinflammatory and neurodegenerative diseases. It regulates the activation of infiltrating cells and resident immune cells. However, the exact functions of CXCR3 in neurological diseases are inconclusive. Thus, it is important to understand the topic of chemokines and the scope of their activity in neurological diseases.

Plasma IFN-γ-inducible chemokines CXCL9 and CXCL10 correlate with survival and chemotherapeutic efficacy in advanced pancreatic ductal adenocarcinoma

OBJECTIVES

Recent studies have suggested that the CXCL9, 10, 11/CXCR3 axis is significant in immune regulation and therapeutic efficacy in human cancers; however, its role in pancreatic ductal adenocarcinoma (PDAC) remains unknown. This study serves to evaluate the prognostic prediction value of plasma IFN-γ-inducible chemokines, CXCL9 and CXCL10, in advanced PDAC.

METHODS

Two hundred patients with advanced PDAC receiving palliative chemotherapy were retrospectively recruited. The association between Plasma CXCL9/CXCL10 levels and survival time was first analyzed in a test group of 110 patients and then confirmed in a validation group of 90 patients.

RESULTS

High levels of CXCL9 and CXCL10 were significantly correlated with longer overall survival (OS) in advanced PDAC patients (314 vs. 136 days for CXCL9, P < 0.0001, and 374 vs. 163 days for CXCL10, P < 0.0001, respectively) in the test group, which was consistent with the results derived from the validation group. In addition, high levels of CXCL9 and CXCL10 were associated with longer time to progression (TTP) in patients receiving chemotherapy (100 vs. 60 days for CXCL9, P = 0.0021, and 104 vs. 67 days for CXCL10, P = 0.0057, respectively). Multivariate analyses confirmed that CXCL9 and CXCL10 were independent prognostic predictors for OS (hazard ratio [HR]: 0.452, P < 0.001 for CXCL9; and HR: 0.586, P = 0.007 for CXCL10, respectively) and TTP (HR: 0.656, P = 0.015 for CXCL9; and HR: 0.687, P = 0.040 for CXCL10, respectively).

CONCLUSIONS

Plasma CXCL9 and CXCL10 can be used to predict survival of advanced PDAC patients receiving chemotherapy, allowing clinicians to potentially improve treatment outcomes by identifying candidates for aggressive therapy.

Immune-relevant aspects of murine models of head and neck cancer

Head and neck cancers (HNCs) cause significant mortality and morbidity. There have been few advances in therapeutic management of HNC in the past 4 to 5 decades, which support the need for studies focusing on HNC biology. In recent years, increased recognition of the relevance of the host response in cancer progression has led to novel therapeutic strategies and putative biomarkers of tumor aggressiveness. However, tumor-immune interactions are highly complex and vary with cancer type. Pre-clinical, in vivo models represent an important and necessary step in understanding biological processes involved in development, progression and treatment of HNC. Rodents (mice, rats, hamsters) are the most frequently used animal models in HNC research. The relevance and utility of information generated by studies in murine models is unquestionable, but it is also limited in application to tumor-immune interactions. In this review, we present information regarding the immune-specific characteristics of the murine models most commonly used in HNC research, including immunocompromised and immunocompetent animals. The particular characteristics of xenograft, chemically induced, syngeneic, transgenic, and humanized models are discussed in order to provide context and insight for researchers interested in the in vivo study of tumor-immune interactions in HNC.

Aberrant RNA Splicing in Cancer and Drug Resistance

More than 95% of the 20,000 to 25,000 transcribed human genes undergo alternative RNA splicing, which increases the diversity of the proteome. Isoforms derived from the same gene can have distinct and, in some cases, opposing functions. Accumulating evidence suggests that aberrant RNA splicing is a common and driving event in cancer development and progression. Moreover, aberrant splicing events conferring drug/therapy resistance in cancer is far more common than previously envisioned. In this review, aberrant splicing events in cancer-associated genes, namely BCL2L1, FAS, HRAS, CD44, Cyclin D1, CASP2, TMPRSS2-ERG, FGFR2, VEGF, AR and KLF6, will be discussed. Also highlighted are the functional consequences of aberrant splice variants (BCR-Abl35INS, BIM-γ, IK6, p61 BRAF V600E, CD19-∆2, AR-V7 and PIK3CD-S) in promoting resistance to cancer targeted therapy or immunotherapy. To overcome drug resistance, we discuss opportunities for developing novel strategies to specifically target the aberrant splice variants or splicing machinery that generates the splice variants. Therapeutic approaches include the development of splice variant-specific siRNAs, splice switching antisense oligonucleotides, and small molecule inhibitors targeting splicing factors, splicing factor kinases or the aberrant oncogenic protein isoforms.

The Role of CXC Chemokine Receptors 1-4 on Immune Cells in the Tumor Microenvironment

Chemokines govern leukocyte migration by attracting cells that express their cognate ligands. Many cancer types show altered chemokine secretion profiles, favoring the recruitment of pro-tumorigenic immune cells and preventing the accumulation of anti-tumorigenic effector cells. This can ultimately result in cancer immune evasion. The manipulation of chemokine and chemokine-receptor signaling can reshape the immunological phenotypes within the tumor microenvironment in order to increase the therapeutic efficacy of cancer immunotherapy. Here we discuss the three chemokine-chemokine receptor axes, CXCR1/2–CXCL1-3/5-8, CXCR3–CXCL9/10/11, and CXCR4-CXCL12 and their role on pro-tumorigenic immune cells and anti-tumorigenic effector cells in solid tumors. In particular, we summarize current strategies to target these axes and discuss their potential use in treatment approaches.

Platelet factor 4 is produced by subsets of myeloid cells in premetastatic lung and inhibits tumor metastasis

Bone marrow-derived myeloid cells can form a premetastatic niche and provide a tumor-promoting microenvironment. However, subsets of myeloid cells have also been reported to have anti-tumor properties. It is not clear whether there is a transition between anti- and pro- tumor function of these myeloid cells, and if so, what are the underlying molecular mechanisms. Here we report platelet factor 4 (PF4), or CXCL4, but not the other family members CXCL9, 10, and 11, was produced at higher levels in the normal lung and early stage premetastatic lungs but decreased in later stage lungs. PF4 was mostly produced by Ly6G+CD11b+ myeloid cell subset. Although the number of Ly6G+CD11b+ cells was increased in the premetastatic lungs, the expression level of PF4 in these cells was decreased during the metastatic progression. Deletion of PF4 (PF4 knockout or KO mice) led an increased metastasis suggesting an inhibitory function of PF4. There were two underlying mechanisms: decreased blood vessel integrity in the premetastatic lungs and increased production of hematopoietic stem/progenitor cells (HSCs) and myeloid derived suppressor cells (MDSCs) in tumor-bearing PF4 KO mice. In cancer patients, PF4 expression levels were negatively correlated with tumor stage and positively correlated with patient survival. Our studies suggest that PF4 is a critical anti-tumor factor in the premetastatic site. Our finding of PF4 function in the tumor host provides new insight to the mechanistic understanding of tumor metastasis.

CXCR3 is a prognostic marker and a potential target for patients with solid tumors: a meta-analysis

OBJECTIVE

To deeply verify the clinical significance of CXCR3 in prediction of cancer patients' prognosis.

DATA SOURCES

We performed a meta-analysis including 12 studies searched from PubMed, Web of Science, Embase, and Cochrane databases. A total of 1,751 patients were used to analyze the association between CXCR3 and patients' prognosis, based on either overall survival or time to tumor progression.

STUDY SELECTION

Studies evaluating CXCR3 expression for predicting prognosis in human solid tumors were included.

RESULTS

It showed that patients with higher expression of CXCR3 had significantly shorter OS (pooled hazard ratio =2.315, 95% CI: 1.162-4.611, P=0.017). In addition, higher CXCR3 expression was associated with distant metastasis (yes vs no: pooled relative ratio [RR] =1.828, 95% CI: 1.140-2.931, P=0.012) in solid tumors and indicated advanced tumor stage (III/IV vs I/II, RR =2.656, 95% CI: 1.809-3.900, P<0.001) and lymph node metastasis (yes vs no: RR =2.28, 95% CI: 1.61-3.25, P<0.001) in colorectal cancer.

CONCLUSION

Our study highlights the role of CXCR3 as a potential prognostic marker and a promising therapeutic target in solid tumors.

A novel microfluidic model can mimic organ-specific metastasis of circulating tumor cells

A biomimetic microsystem might compensate costly and time-consuming animal metastatic models. Herein we developed a biomimetic microfluidic model to study cancer metastasis. Primary cells isolated from different organs were cultured on the microlfuidic model to represent individual organs. Breast and salivary gland cancer cells were driven to flow over primary cell culture chambers, mimicking dynamic adhesion of circulating tumor cells (CTCs) to endothelium in vivo. These flowing artificial CTCs showed different metastatic potentials to lung on the microfluidic model. The traditional nude mouse model of lung metastasis was performed to investigate the physiological similarity of the microfluidic model to animal models. It was found that the metastatic potential of different cancer cells assessed by the microfluidic model was in agreement with that assessed by the nude mouse model. Furthermore, it was demonstrated that the metastatic inhibitor AMD3100 inhibited lung metastasis effectively in both the microfluidic model and the nude mouse model. Then the microfluidic model was used to mimick liver and bone metastasis of CTCs and confirm the potential for research of multiple-organ metastasis. Thus, the metastasis of CTCs to different organs was reconstituted on the microfluidic model. It may expand the capabilities of traditional cell culture models, providing a low-cost, time-saving, and rapid alternative to animal models.

CXCL9, CXCL10, CXCL11/CXCR3 axis for immune activation - A target for novel cancer therapy

Chemokines are proteins which induce chemotaxis, promote differentiation of immune cells, and cause tissue extravasation. Given these properties, their role in anti-tumor immune response in the cancer environment is of great interest. Although immunotherapy has shown clinical benefit for some cancer patients, other patients do not respond. One of the mechanisms of resistance to checkpoint inhibitors may be chemokine signaling. The CXCL9, -10, -11/CXCR3 axis regulates immune cell migration, differentiation, and activation, leading to tumor suppression (paracrine axis). However, there are some reports that show involvements of this axis in tumor growth and metastasis (autocrine axis). Thus, a better understanding of CXCL9, -10, -11/CXCR3 axis is necessary to develop effective cancer control. In this article, we summarize recent evidence regarding CXCL9, CXCL10, CXCL11/CXCR3 axis in the immune system and discuss their potential role in cancer treatment.

Tensor decomposition-based unsupervised feature extraction applied to matrix products for multi-view data processing

In the current era of big data, the amount of data available is continuously increasing. Both the number and types of samples, or features, are on the rise. The mixing of distinct features often makes interpretation more difficult. However, separate analysis of individual types requires subsequent integration. A tensor is a useful framework to deal with distinct types of features in an integrated manner without mixing them. On the other hand, tensor data is not easy to obtain since it requires the measurements of huge numbers of combinations of distinct features; if there are m kinds of features, each of which has N dimensions, the number of measurements needed are as many as N^m, which is often too large to measure. In this paper, I propose a new method where a tensor is generated from individual features without combinatorial measurements, and the generated tensor was decomposed back to matrices, by which unsupervised feature extraction was performed. In order to demonstrate the usefulness of the proposed strategy, it was applied to synthetic data, as well as three omics datasets. It outperformed other matrix-based methodologies.

Combination of DESI2 and IP10 gene therapy significantly improves therapeutic efficacy against murine carcinoma

DESI2 (also known as PNAS-4) is a novel pro-apoptotic gene activated during the early response to DNA damage. We previously reported that overexpression of DESI2 induces S phase arrest and apoptosis by activating checkpoint kinases. The present study was designed to test whether combination of DESI2 and IP10 could improve the therapy efficacy in vitro and in vivo. The recombinant plasmid co-expressing DESI2 and IP10 was encapsulated with DOTAP/Cholesterol nanoparticle. Immunocompetent mice bearing CT26 colon carcinoma and LL2 lung cancer were treated with the complex. We found that, in vitro, the combination of DESI2 and IP10 more efficiently inhibited proliferation of CT26, LL2, SKOV3 and A549 cancer cells via apoptosis. In vivo, the combined gene therapy more significantly inhibited tumor growth and efficiently prolonged the survival of tumor bearing mice. Mechanistically, the augmented antitumor activity in vivo was associated with induction of apoptosis and inhibition of angiogenesis. The anti-angiogenesis was further mimicked by inhibiting proliferation of immortalized HUVEC cells in vitro. Meanwhile, the infiltration of lymphocytes also contributed to the enhanced antitumor effects. Depletion of CD8+ T lymphocytes significantly abrogated the antitumor activity, whereas depletion of CD4+ T cells or NK cells showed partial abrogation. Our data suggest that the combined gene therapy of DESI2 and IP10 can significantly enhance the antitumor activity as apoptosis inducer, angiogenesis inhibitor and immune response initiator. The present study may provide a novel and effective method for treating cancer.

Induction of cathepsin B by the CXCR3 chemokines CXCL9 and CXCL10 in human breast cancer cells

Cathepsin B (CTSB) is a lysosomal cysteine protease that has been linked to the progression of breast cancer, for example by activation of other proteases and tumor-promoting cytokines, thereby supporting tumor invasion and metastasis. Previously, it was shown that CTSB cleaves and inactivates C-X-C motif chemokine receptor 3 (CXCR3) chemokines. As CXCR3 ligands have been demonstrated to induce proteases in cancer cells, the present study hypothesized that they may also affect CTSB in breast cancer cells. The results demonstrated that the human breast cancer tumor cell lines MCF-7 and MDA-MB-231 express the CXCR3 splice variants A and B and CTSB. Upon binding to CXCR3, the two chemokine ligands C-X-C motif chemokine ligand (CXCL) 9 and CXCL10 trigger upregulation of CTSB in these breast cancer cells, whereas the CXCR3-B-specific ligand CXCL4 has no such effect, suggesting the involvement of CXCR3-A in the regulation of CTSB. In early-stage human breast cancer specimens (n=81), overexpression of CXCR3 is associated with statistically significant poorer overall survival, independent of lymph node status, tumor size and nuclear grading (hazard ratio=1.99; 95% confidence interval=1.00–3.97; P=0.050). In conclusion, the data from the current study propose a so far unknown mechanism by which breast cancer cells may exploit tumor-suppressive chemokines to enhance their invasiveness and reduce immune cell infiltration by the degradation of these chemokines. This mechanism may support the established unfavorable prognostic feature of CXCR3 expression in breast cancer.