CXCL10 reduces melanoma proliferation and invasiveness in vitro and in vivo

Reshaping tumor microenvironment by regulating local cytokines expression with a portable smart blue-light controlled device

Cytokines have attracted sustained attention due to their multi-functional cellular response in immunotherapy. However, their application was limited to their short half-time, narrow therapeutic window, and undesired side effects. To address this issue, we developed a portable smart blue-light controlled (PSLC) device based on optogenetic technology. By combining this PSLC device with blue-light controlled gene modules, we successfully achieved the targeted regulation of cytokine expression within the tumor microenvironment. To alter the tumor microenvironment of solid tumors, pro-inflammatory cytokines were selected as blue-light controlled molecules. The results show that blue-light effectively regulates the expression of pro-inflammatory cytokines both in vitro and in vivo. This strategy leads to enhanced and activated tumor-infiltrating immune cells, which facilitated to overcome the immunosuppressive microenvironment, resulting in significant tumor shrinkage in tumor-bearing mice. Hence, our study offers a unique strategy for cytokine therapy and a convenient device for animal studies in optogenetic immunotherapy.

Chemokines and Cytokines in Immunotherapy of Melanoma and Other Tumors: From Biomarkers to Therapeutic Targets

Chemokines and cytokines represent an emerging field of immunotherapy research. They are responsible for the crosstalk and chemoattraction of immune cells and tumor cells. For instance, CXCL9/10/11 chemoattract effector CD8+ T cells to the tumor microenvironment, making an argument for their promising role as biomarkers for a favorable outcome. The cytokine Interleukin-15 (IL-15) can promote the chemokine expression of CXCR3 ligands but also XCL1, contributing to an important DC-T cell interaction. Recruited cytotoxic T cells can be clonally expanded by IL-2. Delivering or inducing these chemokines and cytokines can result in tumor shrinkage and might synergize with immune checkpoint inhibition. In addition, blocking specific chemokine and cytokine receptors such as CCR2, CCR4 or Il-6R can reduce the recruitment of tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs) or regulatory T cells (Tregs). Efforts to target these chemokines and cytokines have the potential to personalize cancer immunotherapy further and address patients that are not yet responsive because of immune cell exclusion. Targeting cytokines such as IL-6 and IL-15 is currently being evaluated in clinical trials in combination with immune checkpoint-blocking antibodies for the treatment of metastatic melanoma. The improved overall survival of melanoma patients might outweigh potential risks such as autoimmunity. However, off-target toxicity needs to be elucidated.

T-cell subsets and cytokines are indicative of neoadjuvant chemoimmunotherapy responses in NSCLC

PURPOSE

Neoadjuvant PD-1 blockade combined with chemotherapy is a promising treatment for resectable non-small cell lung cancer (NSCLC), yet the immunological mechanisms contributing to tumor regression and biomarkers corresponding to different pathological responses remain unclear.

METHODS

Using dynamic and paired blood samples from NSCLC patients receiving neoadjuvant chemoimmunotherapy, we analyzed the frequencies of CD8 + T-cell and Treg subsets and their dynamic changes during neoadjuvant treatment through flow cytometry. Cytokine profiles and function-related gene expression of CD8 + T cells and Tregs were analyzed through flow cytometry and mRNA-seq. Infiltrating T-cell subsets in resected tissues from patients with different pathological responses were analyzed through multiplex immunofluorescence.

RESULTS

Forty-two NSCLC patients receiving neoadjuvant chemoimmunotherapy were enrolled and then underwent surgical resection and pathological evaluation. Nineteen patients had pCR (45%), 7 patients had MPR (17%), and 16 patients had non-MPR (38%). In patients with pCR, the frequencies of CD137 + CD8 + T cells (P = 0.0475), PD-1 + Ki-67 + CD8 + T cells (P = 0.0261) and Tregs (P = 0.0317) were significantly different from those of non-pCR patients before treatment. pCR patients usually had low frequencies of CD137 + CD8 + T cells, PD-1 + Ki-67 + CD8 + T cells and Tregs, and their AUCs were higher than that of tissue PD-L1 expression. Neoadjuvant chemoimmunotherapy markedly improved CD8 + T-cell proliferation and activation, especially in pCR patients, as the frequencies of CD137 + CD8 + (P = 0.0136) and Ki-67 + CD8 + (P = 0.0391) T cells were significantly increased. The blood levels of cytokines such as IL-2 (P = 0.0391) and CXCL10 (P = 0.0195) were also significantly increased in the pCR group, which is consistent with the high density of activated cytotoxic T cells at the tumor site (P < 0.0001).

CONCLUSION

Neoadjuvant chemoimmunotherapy drives CD8 + T cells toward a proliferative and active profile. The frequencies of CD137 + CD8 + T cells, PD-1 + Ki-67 + CD8 + T cells and Tregs at baseline might predict the response to neoadjuvant chemoimmunotherapy in NSCLC patients. The increase in IL-2 and CXCL10 might reflect the chemotaxis and enrichment of cytotoxic T cells at the tumor site and a better response to neoadjuvant chemoimmunotherapy.

Leveraging STING, Batf3 Dendritic Cells, CXCR3 Ligands, and Other Components Related to Innate Immunity to Induce A "Hot" Tumor Microenvironment That Is Responsive to Immunotherapy

In a T-cell-inflamed phenotype, tumor eradication works best and is potentiated by immunotherapy such as checkpoint blockade. However, a majority of patients die despite receiving immunotherapy. One reason is insufficient T cell priming and infiltration in the tumor. Nature provides us with innate immune mechanisms in T-cell-inflamed tumors that we can adopt for more personalized immunotherapy strategies. Tumor sensing through innate signaling pathways and efficient antigen-presenting possess a significant role in bridging innate and adaptive immunity and generating a T-cell-inflamed tumor. One approach to strengthen these innate immune mechanisms is to deliver innate immune factors such as STING or activated DCs into the tumor microenvironment, in particular in patients resistant to checkpoint blockade. The low number of DCs in the tumor bed could potentially be increased with the growth factor FMS-like tyrosine kinase 3 ligand (Flt3L). CD103+ DCs are integral for three phases of anti-tumor immunity: priming, recruiting, and re-invigoration of effector T cells. Re-activation of dysfunctional T cells is achieved via co-stimulatory molecules such as the 4-1BB ligand. The presence of myeloid-cell-derived CXCL9 and CXCL10 in the tumor microenvironment can predict response to immunotherapy. We outline recent preclinical and clinical approaches to deliver these crucial components bridging innate and adaptive immunity into the tumor microenvironment.

Determination of WWOX Function in Modulating Cellular Pathways Activated by AP-2α and AP-2γ Transcription Factors in Bladder Cancer

Following the invention of high-throughput sequencing, cancer research focused on investigating disease-related alterations, often inadvertently omitting tumor heterogeneity. This research was intended to limit the impact of heterogeneity on conclusions related to WWOX/AP-2α/AP-2γ in bladder cancer which differently influenced carcinogenesis. The study examined the signaling pathways regulated by WWOX-dependent AP-2 targets in cell lines as biological replicates using high-throughput sequencing. RT-112, HT-1376 and CAL-29 cell lines were subjected to two stable lentiviral transductions. Following CAGE-seq and differential expression analysis, the most important genes were identified and functionally annotated. Western blot was performed to validate the selected observations. The role of genes in biological processes was assessed and networks were visualized. Ultimately, principal component analysis was performed. The studied genes were found to be implicated in MAPK, Wnt, Ras, PI3K-Akt or Rap1 signaling. Data from pathways were collected, explaining the differences/similarities between phenotypes. FGFR3, STAT6, EFNA1, GSK3B, PIK3CB and SOS1 were successfully validated at the protein level. Afterwards, a definitive network was built using 173 genes. Principal component analysis revealed that the various expression of these genes explains the phenotypes. In conclusion, the current study certified that the signaling pathways regulated by WWOX and AP-2α have more in common than that regulated by AP-2γ. This is because WWOX acts as an EMT inhibitor, AP-2γ as an EMT enhancer while AP-2α as a MET inducer. Therefore, the relevance of AP-2γ in targeted therapy is now more evident. Some of the differently regulated genes can find application in bladder cancer treatment.

Cxcl10 chemokine induces migration of ING4-deficient breast cancer cells via a novel crosstalk mechanism between the Cxcr3 and Egfr receptors

The chemokine Cxcl10 has been associated with poor prognosis in breast cancer, but the mechanism is not well understood. Our previous study have shown that CXCL10 was repressed by the ING4 tumor suppressor, suggesting a potential inverse functional relationship. We thus investigated a role for Cxcl10 in the context of ING4 deficiencies in breast cancer. We first analyzed public gene expression datasets and found that patients with CXCL10-high/ING4-low expressing tumors had significantly reduced disease-free survival in breast cancer. In vitro, Cxcl10 induced migration of ING4-deleted breast cancer cells, but not of ING4-intact cells. Using inhibitors, we found that Cxcl10-induced migration of ING4-deleted cells required Cxcr3, Egfr, and the Gβγ subunits downstream of Cxcr3, but not Gαi. Immunofluorescent imaging showed that Cxcl10 induced early transient colocalization between Cxcr3 and Egfr in both ING4-intact and ING4-deleted cells, which recurred only in ING4-deleted cells. A peptide agent that binds to the internal juxtamembrane domain of Egfr inhibited Cxcr3/Egfr colocalization and cell migration. Taken together, these results presented a novel mechanism of Cxcl10 that elicits migration of ING4-deleted cells, in part by inducing a physical or proximal association between Cxcr3 and Egfr and signaling downstream via Gβγ. These results further indicated that ING4 plays a critical role in the regulation of Cxcl10 signaling that enables breast cancer progression.

Identification of Genes Potentially Associated with Melanoma Tumorigenesis Through Co-Expression Network Analysis

Background

Melanoma is one of the most malignant and aggressive skin tumors, and its incidence is increasing worldwide. However, few studies have investigated the process of tumorigenesis from normal skin to melanoma.

Methods

Several bioinformatics analyses, including GEO databases, Oncomine database, TCGA database, STRING, MCODE and cytoHubba plug-ins, GEPIA, TIMER and TRRUST and DGIdb, were performed to disclose the hub genes and immunology implicated in primary melanoma tumorigenesis. Finally, immunohistochemistry (IHC) and quantitative real-time PCR (qPCR) were used to validate the results of bioinformatics analysis in vitro.

Results

A total of 295 overlapping DEGs (ODEGs) (157 upregulated and 138 downregulated) and 9 hub genes were identified between primary melanoma and normal skin tissues. Functional analysis of these 9 hub genes indicated that the genes were primarily enriched in cell chemotaxis, the chemokine-mediated signaling pathway, the extracellular region, the extracellular space, chemokine activity and CXCR3 chemokine receptor binding. KEGG pathway enrichment showed that these genes were primarily involved in the chemokine signaling pathway, cytokine–cytokine receptor interaction, the toll-like receptor signaling pathway, the cytosolic DNA-sensing pathway and the TNF signaling pathway. Upregulated CCL5, CCL4, CXCL9 and CXCL10 demonstrated good overall survival (OS), and most of them have a higher expression in stage 0 and 1 of melanoma. Moreover, immune infiltration analysis showed that the above hub genes showed a strong positive correlation between their expression and infiltration of the six immune cell subsets. Transcription factor regulation network suggested that RELA and NFKB1 are the transcription factors of CCL4, CCL5, CXCL10 and CXCL2, while IRF7, IRF3 and IRF1 are the transcription factors of CCL5 and CXCL10. Drug–gene interaction analysis identified 46 drug–gene interactions. In vitro data demonstrated that the level of CCL4, CCL5, CXCL9 and CXCL10 is higher in melanoma than that in normal skin tissues, either at tissue or cell lines level.

Conclusion

In summary, we identified 4 key chemokine members related to tumorigenesis and progression in primary melanoma, and these results may help to elucidate melanoma tumorigenesis and facilitate its treatment.

Chemokine Pathways in Cutaneous Melanoma: Their Modulation by Cancer and Exploitation by the Clinician

The incidence of cutaneous malignant melanoma is rising globally and is projected to continue to rise. Advances in immunotherapy over the last decade have demonstrated that manipulation of the immune cell compartment of tumours is a valuable weapon in the arsenal against cancer; however, limitations to treatment still exist. Cutaneous melanoma lesions feature a dense cell infiltrate, coordinated by chemokines, which control the positioning of all immune cells. Melanomas are able to use chemokine pathways to preferentially recruit cells, which aid their growth, survival, invasion and metastasis, and which enhance their ability to evade anticancer immune responses. Aside from this, chemokine signalling can directly influence angiogenesis, invasion, lymph node, and distal metastases, including epithelial to mesenchymal transition-like processes and transendothelial migration. Understanding the interplay of chemokines, cancer cells, and immune cells may uncover future avenues for melanoma therapy, namely: identifying biomarkers for patient stratification, augmenting the effect of current and emerging therapies, and designing specific treatments to target chemokine pathways, with the aim to reduce melanoma pathogenicity, metastatic potential, and enhance immune cell-mediated cancer killing. The chemokine network may provide selective and specific targets that, if included in current therapeutic regimens, harbour potential to improve outcomes for patients.

Immune cell and tumor cell-derived CXCL10 is indicative of immunotherapy response in metastatic melanoma

A T cell-inflamed tumor microenvironment is characterized by the accumulation and local activation of CD8⁺ T cells and Bat3-lineage dendritic cells, which together are associated with clinical response to anti-programmed cell death protein 1 (anti-PD-1)-based immunotherapy. Preclinical models have demonstrated a crucial role for the chemokine CXCL10 in the recruitment of effector CD8⁺ T cells into the tumor site, and a chemokine gene signature is also seen in T cell-inflamed tumors from patients. However, the cellular source of CXCL10 in human solid tumors is not known. To identify the cellular source of CXCL10 we analyzed 22 pretreatment biopsy samples of melanoma metastases from patients who subsequently underwent checkpoint blockade immunotherapy. We stained for CD45⁺ and Sox10⁺ cells with multiparameter immunofluorescence staining, and RNA in situ hybridization technology was used in concert to identify CXCL10 transcripts. The results were correlated with the expression levels of CXCL10 transcripts from bulk RNA sequencing and the best overall response to immune checkpoint inhibition (anti-PD-1 alone or with anti-CTLA-4) in the same patients. We identified CD45⁺ cells as the major cellular source for CXCL10 in human melanoma metastases, with additional CXCL10 production seen by Sox10⁺ cells. Up to 90% of CD45⁺ cells and up to 69% of Sox10⁺ cells produced CXCL10 transcripts. The CXCL10 staining result was consistent with the level of CXCL10 expression determined by bulk RNA sequencing. The percentages of CD45⁺ CXCL10⁺ cells and Sox10⁺ CXCL10⁺ cells independently predicted response (p<0.001). The average number of transcripts per cell correlated with the CD45⁺ cell infiltrate (R=0.37). Immune cells and melanoma cells produce CXCL10 in human melanoma metastases. Intratumoral CXCL10 is a positive prognostic factor for response to immunotherapy, and the RNAscope technique is achievable using paraffin tissue. Strategies that support effector T cell recruitment via induction of CXCL10 should be considered as a mechanism-based intervention to expand immunotherapy efficacy.

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.

CXCR3 Ligands in Cancer and Autoimmunity, Chemoattraction of Effector T Cells, and Beyond

CXCR3 is a chemokine receptor with three ligands; CXCL9, CXCL10, and CXCL11. CXCL11 binds CXCR3 with a higher affinity than the other ligands leading to receptor internalization. Long ago we reported that one of these chemokines, CXCL10, not only attracts CXCR3+ CD4+ and CD8+ effector T cells to sites of inflammation, but also direct their polarization into highly potent effector T cells. Later we showed that CXCL11 directs the linage development of T-regulatory-1 cells (Tr1). We also observed that CXCL11 and CXCL10 induce different signaling cascades via CXCR3. Collectively this suggests that CXCR3 ligands differentially regulate the biological function of T cells via biased signaling. It is generally accepted that tumor cells evolved to express several chemokine receptors and secrete their ligands. Vast majority of these chemokines support tumor growth by different mechanisms that are discussed. We suggest that CXCL10 and possibly CXCL9 differ from other chemokines by their ability to restrain tumor growth and enhance anti-tumor immunity. Along with this an accumulating number of studies showed in various human cancers a clear association between poor prognosis and low expression of CXCL10 at tumor sites, and vice versa. Finally, we discuss the possibility that CXCL9 and CXCL10 may differ in their biological function via biased signaling and its possible relevance to cancer immunotherapy. The current mini review focuses on exploring the role of CXCR3 ligands in directing the biological properties of CD4+ and CD8+ T cells in the context of cancer and autoimmunity. We believe that the combined role of these chemokines in attracting T cells and also directing their biological properties makes them key drivers of immune function.

CXCL-10: a new candidate for melanoma therapy?

BACKGROUND

Melanoma is a malignancy that stems from melanocytes and is defined as the most dangerous skin malignancy in terms of metastasis and mortality rates. CXC motif chemokine 10 (CXCL10), also known as interferon gamma-induced protein-10 (IP-10), is a small cytokine-like protein secreted by a wide variety of cell types. CXCL10 is a ligand of the CXC chemokine receptor-3 (CXCR3) and is predominantly expressed by T helper cells (Th cells), cytotoxic T lymphocytes (CTLs), dendritic cells, macrophages, natural killer cells (NKs), as well as some epithelial and cancer cells. Similar to other chemokines, CXCL10 plays a role in immunomodulation, inflammation, hematopoiesis, chemotaxis and leukocyte trafficking.

CONCLUSIONS

Recent studies indicate that the CXCL10/CXCR3 axis may act as a double-edged sword in terms of pro- and anti-cancer activities in a variety of tissues and cells, especially in melanoma cells and their microenvironments. Most of these activities arise from the CXCR3 splice variants CXCR3-A, CXCR3-B and CXCR3-Alt. In this review, we discuss the pro- and anti-cancer properties of CXCL10 in various types of tissues and cells, particularly melanoma cells, including its potential as a therapeutic target.

Comprehensive analysis of prognostic immune-related genes in the tumor microenvironment of cutaneous melanoma

Cutaneous malignant melanoma (hereafter called melanoma) is one of the most aggressive cancers with increasing incidence and mortality rates worldwide. In this study, we performed a systematic investigation of the tumor microenvironmental and genetic factors associated with melanoma to identify prognostic biomarkers for melanoma. We calculated the immune and stromal scores of melanoma patients from the Cancer Genome Atlas (TCGA) using the ESTIMATE algorithm and found that they were closely associated with patients' prognosis. Then the differentially expressed genes were obtained based on the immune and stromal scores, and prognostic immune-related genes further identified. Functional analysis and the protein-protein interaction network further revealed that these genes enriched in many immune-related biological processes. In addition, the abundance of six infiltrating immune cells was analyzed using prognostic immune-related genes by TIMER algorithm. The unsupervised clustering analysis using immune-cell proportions revealed eight clusters with distinct survival patterns, suggesting that dendritic cells were most abundant in the microenvironment and CD8⁺ T cells and neutrophils were significantly related to patients' prognosis. Finally, we validated these genes in three independent cohorts from the Gene Expression Omnibus database. In conclusion, this study comprehensively analyzed the tumor microenvironment and identified prognostic immune-related biomarkers for melanoma.

Differential Gene Expression in Primary Cultured Sensory and Motor Nerve Fibroblasts

Fibroblasts (Fbs) effectively promote Schwann cells (SCs) migration, proliferation, and neurite regeneration. Whether Fbs express different motor and sensory phenotypes that regulate the cell behavior and peripheral nerve function has not been elucidated. The present study utilized the whole rat genome microarray analysis and identified a total of 121 differentially expressed genes between the primary cultured motor and sensory Fbs. The genes with high expression in sensory Fbs were related to proliferation, migration, chemotaxis, motility activation, protein maturation, defense response, immune system, taxis, and regionalization, while those with high expression in motor Fbs were related to neuron differentiation, segmentation, and pattern specification. Thus, the significant difference in the expression of some key genes was found to be associated with cell migration and proliferation, which was further validated by quantitative real-time PCR (qPCR). The cell proliferation or migration analysis revealed a higher rate of cell migration and proliferation of sensory Fbs than motor Fbs. Moreover, the downregulated expression of chemokine (C-X-C motif) ligand 10 (CXCL10) and chemokine (C-X-C motif) ligand 3 (CXCL3) suppressed the proliferation rate of sensory Fbs, while it enhanced that of the motor Fbs. However, the migration rate of both Fbs was suppressed by the downregulated expression of CXCL10 or CXCL3. Furthermore, a higher proportion of motor or sensory SCs migrated toward their respective (motor or sensory) Fbs; however, few motor or sensory SCs co-cultured with the other type of Fbs (sensory or motor, respectively), migrated toward the Fbs. The current findings indicated that Fbs expressed the distinct motor and sensory phenotypes involved in different patterns of gene expression, biological processes, and effects on SCs. Thus, this study would provide insights into the biological differences between motor and sensory Fbs, including the role in peripheral nerve regeneration.

CXCL5 as Regulator of Neutrophil Function in Cutaneous Melanoma

Chemokines mold the tumor microenvironment by recruiting distinct immune cell populations, thereby strongly influencing disease progression. Previously, we showed that CXCL5 expression is upregulated in advanced stages of primary melanomas, which correlates with the presence of neutrophils in the tumor. The analysis of neutrophil populations in various tissues revealed a distinct phenotype of tumor-associated neutrophils. Tumor-associated neutrophils expressed PD-L1, CXCR4, CCR5, Adam17, and Nos2 and were immunosuppressive in a T-cell proliferation assay. To investigate the impact of CXCL5 and neutrophils in vivo, we established a syngeneic mouse tumor transplantation model using CXCL5-overexpressing and control melanoma cell lines. Growth behavior or vascularization of primary tumors was not affected by CXCL5 expression and neutrophils alone. However, in combination with Poly(I:C), tumor-associated neutrophils were able to attenuate induced antitumoral T-cell responses. CXCL5-overexpressing tumors had reduced lung metastasis compared with control tumors. Neutrophil depletion reversed this effect. In vitro, unstimulated lung-derived neutrophils had higher levels of reactive oxygen species compared with tumor-associated neutrophils, and CXCL5 stimulation further increased reactive oxygen species levels. In summary, in melanoma, neutrophils play a context-dependent role that is influenced by local or systemic factors, and interfere with therapies activating the acquired immune system. Actively switching neutrophils into antitumorigenic mode might be a new therapeutic strategy.

PDGFR-alpha inhibits melanoma growth via CXCL10/IP-10: a multi-omics approach

Melanoma is the most aggressive skin-cancer, showing high mortality at advanced stages. Platelet Derived Growth Factor Receptor-alpha (PDGFR-alpha) potently inhibits melanoma- and endothelium-proliferation and its expression is significantly reduced in melanoma-biopsies, suggesting that melanoma progression eliminates cells expressing PDGFR-alpha. In the present study transient overexpression of PDGFR-alpha in endothelial (HUVEC) and melanoma (SKMel-28, A375, Preyer) human-cells shows strong anti-proliferative effects, with profound transcriptome and miRNome deregulation. PDGFR-alpha overexpression strongly affects expression of 82 genes in HUVEC (41 up-, 41 down-regulated), and 52 genes in SKMel-28 (43 up-, 9 down-regulated). CXCL10/IP-10 transcript showed up to 20 fold-increase, with similar changes detectable at the protein level. miRNA expression profiling in cells overexpressing PDGFR-alpha identified 14 miRNAs up- and 40 down-regulated, with miR-503 being the most down-regulated (6.4 fold-reduction). miR-503, miR-630 and miR-424 deregulation was confirmed by qRT-PCR. Interestingly, the most upregulated transcript (i.e., CXCL10/IP-10) was a validated miR-503 target and CXCL10/IP-10 neutralization significantly reverted the anti-proliferative action of PDGFR-alpha, and PDGFR-alpha inhibition by Dasatinb totally reverted the CXCL10/IP10 induction, further supporting a functional interplay of these factors. Finally, integration of transcriptomics and miRNomics data highlighted several pathways affected by PDGFR-alpha.

This study demonstrates for the first time that PDGFR-alpha strongly inhibits endothelial and melanoma cells proliferation in a CXCL10/IP-10 dependent way, via miR-503 down-regulation.

CXCL5 Facilitates Melanoma Cell-Neutrophil Interaction and Lymph Node Metastasis

Chemokines influence tumor metastasis by targeting tumor, stromal, and hematopoietic cells. Characterizing the chemokine mRNA expression profile of human primary melanoma samples, we found CXCL5 significantly up-regulated in stage T4 primary melanomas when compared to thin melanomas (T1 stage). To characterize the role of CXCL5 in melanoma progression, we established a metastasizing murine xenograft model using CXCL5-overexpressing human melanoma cells. CXCL5 had no effect on melanoma proliferation in vitro and on primary tumor growth in vivo, but CXCL5-overexpressing tumors recruited high amounts of neutrophils and exhibited significantly increased lymphangiogenesis in our severe combined immune-deficient mouse model. Recruited neutrophils were found in close proximity to or within lymphatic vessels, often in direct contact with melanoma cells. Clinically, CXCL5-overexpressing melanomas had significantly increased lymph node metastases. We were able to translate these findings to human patient samples and found a positive correlation between CXCL5 expression, numbers of neutrophils in stage T4 primary melanoma, and the occurrence of subsequent locoregional metastasis.

Chemokine receptor patterns in lymphocytes mirror metastatic spreading in melanoma

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

CXCL10/CXCR3 overexpression as a biomarker of poor prognosis in patients with stage II colorectal cancer

The CXCL10/CXCR3 axis of inflammatory mediators is one of the most important groups of chemokine axes, which has been proven to be a lymphocyte-associated metastasis mediator in several tumors. The term inflammatory adhesions refers to tumors found to be attached to the surrouding tissues during surgery, although no cancer cell infiltration is later identified on pathological examination. The aim of the present study was to investigate the clinical characteristics of stage II colorectal cancer (CRC) and determine the correlation between the CXCL10/CXCR3 axis, inflammatory adhesions and prognosis. Clinicohistopathological data were collected from 401 CRC patients who had undergone R0 resection. Statistical analysis was performed with SPSS 17.0 software. Immunohistochemistry (IHC) was applied to measure the expression of CXCL10 and CXCR3 in 71 recurrent CRC patients, 72 non-recurrent CRC patients and 10 samples from normal peritumoral tissues, all retrieved from the Tianjin Medical University Cancer Institute and Hospital, Tianjin, China. Inflammatory adhesions, tumor location and size and the number of high-risk factors for reccurrence were more significantly associated with overall survival (OS) rather than disease-free survival in all the patients as determined by the log-rank and Cox's regression hazard analysis. Further analysis demonstrated that only the presence of inflammatory adhesions (P=0.025) was associated with the OS of recurrent patients. Patients with recurrence exhibited higher CXCR3 (P<0.001) and CXCL10 (P<0.001) expression compared with non-recurrent patients, as determined by IHC. The correlation between clinicopathological variables, CXCL10/CXCR3 expression and survival was also analyzed: Inflammatory adhesions and general tumor type (ulcerated vs. elevated) exhibited a significant correlation with CXCR3; however, the expression of CXCL10 was not significantly correlated with tumor location, histological type, size, gender, or preoperative carcinoembryonic antigen and hemoglobin levels. Furthermore, patients exhibiting a high expression of CXCR3 presented with a higher risk of relapse; among those, patients with inflammatory adhesions always exhibited worse survival. However, no such association was identified for CXCL10 expression. In conclusion, CXCR3 expression may be used as a prognostic marker and may contribute to the prediction of clinical outcome in stage II CRC patients.

Oncogenic CXCL10 signalling drives metastasis development and poor clinical outcome

Background:

The CXCL10/CXCR3 signalling mediates paracrine interactions between tumour and stromal cells that govern leukocyte trafficking and angiogenesis. Emerging data implicate noncanonical CXCL10/CXCR3 signalling in tumourigenesis and metastasis. However, little is known regarding the role for autocrine CXCL10/CXCR3 signalling in regulating the metastatic potential of individual tumour clones.

Methods:

We performed transcriptomic and cytokine profiling to characterise the functions of CXCL10 and CXCR3 in tumour cells with different metastatic abilities. We modulated the expression of the CXCL10/CXCR3 pathway using shRNA-mediated silencing in both in vitro and in vivo models of B16F1 melanoma. In addition, we examined the expression of CXCL10 and CXCR3 and their associations with clinical outcomes in clinical data sets derived from over 670 patients with melanoma and colon and renal cell carcinomas.

Results:

We identified a critical role for autocrine CXCL10/CXCR3 signalling in promoting tumour cell growth, motility and metastasis. Analysis of publicly available clinical data sets demonstrated that coexpression of CXCL10 and CXCR3 predicted an increased metastatic potential and was associated with early metastatic disease progression and poor overall survival.

Conclusion:

These findings support the potential for CXCL10/CXCR3 coexpression as a predictor of metastatic recurrence and point towards a role for targeting of this oncogenic axis in the treatment of metastatic disease.

Antitumor efficacy of CC motif chemokine ligand 19 in colorectal cancer

OBJECTIVES

To investigate the function of CC motif chemokine ligand 19 (CCL19) in colorectal cancer (CRC).

METHODS

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry were performed separately to detect the expression of CCL19 in colorectal carcinoma tissues. The expression of CCL19 and its receptor (CCR7) in CRC cell lines were screened by Western blot. SW620, SW1116 and LoVo cell lines were screened and processed with recombinant human CCL19 (rhCCL19) or si-CCL19 RNA. Cell proliferation assay and transwell assay were performed to evaluate the proliferation, migration and invasion of CRC cells, respectively. And the role of proangiogenesis was checked by endothelial tube formation assay.

RESULTS

qRT-PCR, Western blot and immunohistochemistry revealed that both CCL19 mRNA and protein were obviously expressed in a lower degree in CRC tissues than normal tissues (P < 0.01). The CCL19 expression correlated with tumor size (P = 0.03) and invasion depth (P = 0.04) in a negative manner and CCL19-positive patients had longer lifespans (P < 0.05). SW620 and SW1116 cells were screened as CCL19/CCR7 high-expression cells, while LoVo was selected as CCL19/CCR7 low-expression cell among seven CRC cell lines by Western blot. The proliferation, migration, invasion and proangiogenesis of SW620 and SW1116 cells were distinctly suppressed after they were stimulated by rhCCL19 (P < 0.05), and the data presented dose-dependency. Oppositely, these abilities were significantly enhanced after CCL19 gene was silenced (P < 0.05). However, the effects of rhCCL19 and si-CCL19 RNA on LoVo were not significant (P > 0.05).

CONCLUSION

Our research findings indicate that CCL19 may play a suppressive role in colorectal tumorigenesis.

Human melanocytes form a PAX3-expressing melanocyte cluster on Matrigel by the cell migration process

BACKGROUND

The interactions between human epidermal melanocytes and their cellular microenvironment are important in the regulation of human melanocyte functions or in their malignant transformation into melanoma. Although the basement membrane extracellular matrix (BM-ECM) is one of major melanocyte microenvironments, the effects of BM-ECM on the human melanocyte functions are not fully explained at a molecular level.

OBJECTIVE

This study was aimed to characterize the molecular and cellular interactions between normal human melanocytes (NHMs) and BM-ECM.

METHODS

We investigated cell culture models of normal human melanocytes or melanoma cells on three-dimensional (3D) Matrigel to understand the roles of the basement membrane microenvironment in human melanocyte functions. Melanogenesis and melanobast biomarker expression in both primary human melanocytes and melanoma cells on 3D Matrigel were evaluated.

RESULTS

We found that NHMs migrated and formed reversible paired box 3 (PAX3) expressing cell clusters on three-dimensional (3D) Matrigel. The melanogenesis was significantly decreased in the PAX3 expressing cell cluster. The expression profile of PAX3, SOX10, and MITF in the melanocyte cluster on 3D Matrigel was similar to that of melanoblasts. Interestingly, PAX3 and SOX10 showed an inverse expression profile in NHMs, whereas the inverse expression pattern of PAX3 and SOX10 was disrupted in melanoma MNT1 and WM266-4 cells.

CONCLUSION

The human melanocyte culture on 3D Matrigel provides an alternative model system to study functions of human melanoblasts. In addition, this system will contribute to the elucidation of PAX3-related tumorigenic mechanisms to understand human melanoma.

Molecular characterization of human skin response to diphencyprone at peak and resolution phases: therapeutic insights

Diphencyprone (DPCP) is a hapten that induces delayed-type hypersensitivity (DTH) reactions. It is used as an immune modulating therapeutic, but its molecular effects in human skin are largely unknown. We studied cellular and molecular characteristics of a recall response to 0.04% DPCP at 3 day (peak) and 14 day (resolution) timepoints using immune markers, RT-PCR and gene array approaches. A peak response showed modulation of ~7,500 mRNA transcripts, with high expression of cytokines that define all major effector T-cell subsets. Concomitant increases in T-cell and CD11c+ dendritic cell (DC) infiltrates were measured. The resolution reaction was characterized by unexpectedly high levels of T-cells and mature (DC-LAMP+) DCs, but with marked decreases in expression of IL-2, IFNγ, and other T-cell derived cytokines. However, negative immune regulators such as IDO1 that were high in peak reactions, continued to have high expression in resolution reactions. In the resolution reaction, ~1,500 mRNA transcripts were significantly different from placebo-treated skin. These data suggest the response to DPCP evolves from an inflammatory/effector peak at day 3 to a more regulated immune response after 14 days. This model system could be useful for further dissection of mechanisms of immune activation or negative immune regulation in human skin.

Photodynamic agents with anti-metastatic activities

A new concept in multifunctional anticancer agents is demonstrated. Tetrakis-(diisopropyl-guanidino) zinc phthalocyanine (Zn-DIGP) exhibits excellent properties as a photodynamic therapy (PDT) agent, as well as potential anti-metastatic activities in vivo. Zn-DIGP exhibits good cellular uptake and low toxicity in the dark (EC50 > 80 μM) and is well tolerated upon its intravenous injection into mice at 8 mg/kg. Upon photoexcitation with red laser light (660 nm), Zn-DIGP exhibits a high quantum yield for singlet oxygen formation (Φ ≈ 0.51) that results in potent phototoxicity to cell cultures (EC50 ≈ 0.16 μM). Zn-DIGP is also capable of inhibiting the formation of tumor colonies in the lungs of C57BL/6 mice injected with B16F10 cells. Zn-DIGP therefore inhibits cancer growth by both light-dependent and light-independent pathways. The anti-metastatic activities of Zn-DIGP possibly result from its ability to interfere with the signaling between chemokine CXCL10 and the G protein-coupled receptor CXCR3. Zn-DIGP is a competitive inhibitor of CXCR3 activation (IC50 = 3.8 μM) and selectively inhibits downstream events such as CXCL10-activated cell migration. Consistent with the presence of feedback regulation between CXCR3 binding and CXCL10 expression, Zn-DIGP causes overexpression of CXCL10. Interestingly, Zn-DIGP binds to CXCR3 without activating the receptor yet is able to cause endocytosis and degradation of this GPCR. To the best of our knowledge, Zn-DIGP is the first PDT agent that can facilitate the photodynamic treatment of primary tumors while simultaneously inhibiting the formation of metastatic tumor colonies by a light-independent mode of action.

IRF-8 controls melanoma progression by regulating the cross talk between cancer and immune cells within the tumor microenvironment

The transcription factor interferon regulatory factor-8 (IRF-8) is crucial for myeloid cell development and immune response and also acts as a tumor suppressor gene. Here, we analyzed the role of IRF-8 in the cross talk between melanoma cells and tumor-infiltrating leukocytes. B16-F10 melanoma cells transplanted into IRF-8-deficient (IRF-8(-/-)) mice grow more rapidly, leading to higher numbers of lung metastasis, with respect to control animals. These events correlated with reduced dendritic cell and T cell infiltration, accumulation of myeloid-derived suppressor cells and a chemokine/chemokine receptor expression profile within the tumor microenvironment supporting tumor growth, angiogenesis, and metastasis. Noticeably, primary tumors developing in IRF-8(-/-) mice displayed a clear-cut inhibition of IRF-8 expression in melanoma cells. Injection of the demethylating agent 5-aza-2'-deoxycytidine into melanoma-bearing IRF-8(-/-) animals induced intratumoral IRF-8 expression and resulted in the re-establishment of a chemokine/ chemokine receptor pattern favoring leukocyte infiltration and melanoma growth arrest. Importantly, intrinsic IRF-8 expression was progressively down-modulated during melanoma growth in mice and in human metastatic melanoma cells with respect to primary tumors. Lastly, IRF-8 expression in melanoma cells was directly modulated by soluble factors, among which interleukin-27 (IL-27), released by immune cells from tumor-bearing mice. Collectively, these results underscore a key role of IRF-8 in the cross talk between melanoma and immune cells, thus revealing its critical function within the tumor microenvironment in regulating melanoma progression and invasiveness.

The emerging role of CXC chemokines and their receptors in cancer

Chemokines and their receptors have a multifaceted role in tumor biology and are implicated in nearly all aspects of cancer growth, survival and dissemination. Modulation of the interaction between chemokines and their cell surface receptor is, therefore, a promising area for the development of new cancer medicines. In this review, we look at the compelling evidence that is emerging to support targeting CXC chemokines, also known as family α chemokines, as novel therapeutic strategies in the treatment of cancer.

The role of melanoma tumor-derived nitric oxide in the tumor inflammatory microenvironment: its impact on the chemokine expression profile, including suppression of CXCL10

Melanoma appears to be heterogeneous in terms of its molecular biology, etiology and epidemiology. We previously reported that the expression of inducible nitric-oxide synthase (iNOS) in melanoma tumor cells is strongly correlated with poor patient survival. Therefore, we hypothesized that nitric oxide (NO) produced by iNOS promotes the melanoma inflammatory tumor microenvironment associated with poor outcome. To understand the role of NO and iNOS in the melanoma inflammatory tumor microenvironment, polymerase chain reaction arrays of inflammatory and autoimmunity genes were performed on a series of stage III melanoma lymph node metastasis samples to compare the gene expression profiles of iNOS-expressing and nonexpressing tumor samples. The results indicate that expression of CXC chemokine ligand 10 (CXCL10) was inversely correlated with iNOS expression, and the high CXCL10-expressing cases had more favorable prognoses than the low CXCL10-expressing cases. Functional studies revealed that treating iNOS-negative/CXCL10-positive melanoma cell lines with a NO donor suppressed the expression of CXCL10. Furthermore, scavenging NO from iNOS-expressing cell lines significantly affected the chemokine expression profile. Culture supernatants from NO scavenger-treated melanoma cells promoted the migration of plasmacytoid dendritic cells, which was diminished when the cells were treated with a CXCL10-neutralizing antibody. CXCL10 has been reported to be an antitumorigenic chemokine. Our study suggests that the production of NO by iNOS inhibits the expression of CXCL10 in melanoma cells and leads to a protumorigenic tumor microenvironment. Inhibiting NO induces an antitumorigenic environment, and thus, iNOS should be considered to be an important therapeutic target in melanoma.

Chemotherapy induces intratumoral expression of chemokines in cutaneous melanoma, favoring T-cell infiltration and tumor control

T-cell infiltration is known to impact tumor growth and is associated with cancer patient survival. However, the molecular cues that favor T-cell infiltration remain largely undefined. Here, using a genetically engineered mouse model of melanoma, we show that CXCR3 ligands and CCL5 synergize to attract effector T cells into cutaneous metastases, and their expression inhibits tumor growth. Treatment of tumor-bearing mice with chemotherapy induced intratumoral expression of these chemokines and favored T-cell infiltration into cutaneous tumors. In patients with melanoma, these chemokines were also upregulated in chemotherapy-sensitive lesions following chemotherapy, and correlated with T-cell infiltration, tumor control, and patient survival. We found that dacarbazine, temozolomide, and cisplatin induced expression of T-cell-attracting chemokines in several human melanoma cell lines in vitro. These data identify the induction of intratumoral expression of chemokines as a novel cell-extrinsic mechanism of action of chemotherapy that results in the recruitment of immune cells with antitumor activity. Therefore, identifying chemotherapeutic drugs able to induce the expression of T-cell-attracting chemokines in cancer cells may represent a novel strategy to improve the efficacy of cancer immunotherapy.