Expression of haematogenous and lymphogenous chemokine receptors and their ligands on uveal melanoma in association with liver metastasis

Understanding the cell survival mechanism of anoikis-resistant cancer cells during different steps of metastasis

Anchorage-independent survival of cancer cells is associated with metastasis as it enables cells to travel to secondary target sites. Tissue integrity is generally maintained by detachment-induced cell death called 'anoikis', but cancer cells undergoing the multistep metastatic process show resistance to anoikis. Anoikis resistance enables these cells to survive through the extracellular matrix (ECM) deprived phase, which starts when cancer cells detach and move into the circulation till cells reach to the secondary target site. Comprehensive analysis of the molecular and functional biology of anoikis resistance in cancer cells will provide crucial details about cancer metastasis, enabling us to identify novel therapeutic targets against cancer cell dissemination and ultimately secondary tumor formation. This review broadly summarizes recent advances in the understanding of cellular and molecular events leading to anoikis and anoikis resistance. It further elaborates more about the signaling cross-talk in anoikis resistance and its regulation during metastasis.

Evaluation of HSP-27, BAP1, BRAF V600E, CCR7, and PD-L1 expression in uveal melanoma on enucleated eyes and metastatic liver tumors

BACKGROUND

The presence of metastatic disease is one of the most important factors limiting survival in patients with uveal melanoma. Studies on proteins associated with metastatic mechanisms are sparse in the literature.

METHODS

Enucleation samples from 15 patients with metastatic uveal melanoma (Group 1), liver metastasectomy samples from 8 patients with metastatic uveal melanoma (Group 2), and enucleation samples from 20 patients with non-metastatic uveal melanoma as controls (Group 3) were included in the study. Antibodies against heat shock protein 27 (HSP-27), BRCA1-associated protein-1 (BAP1), C-C chemokine receptor 7 (CCR7), B-Raf proto-oncogene serine/threonine-protein kinase V600E (BRAF V600E), and programmed death-ligand 1 (PD-L1) were used to detect immunoreactivity in each sample by immunohistochemical methods. Correlations between these expressed proteins and selected histopathological and clinical features, and metastatic process were investigated.

RESULTS

The frequencies of HSP-27 (median score: Group 1: 8, Group 2: 12, Group 3: 4) and BRAF V600E expressions (number of samples: Group 1: 4 (26.7%), Group 2: 1 (12.5%), Group 3: 0 (0%)), and BAP1 expression loss (number of samples : Group 1: 12 (80%), Group 2: 8 (100%), Group 3: 9 (45%)) were higher in samples from patients with metastatic uveal melanoma (Group 1 + 2) than in those from patients with non-metastatic disease (Group 3) (P = 0.001, P = 0.034, and P = 0.007, respectively). CCR7 expression (median score: Group 1: 0, Group 2: 2, Group 3: 3) was similar among these three groups (P = 0.136). No samples exhibited PD-L1 expression (P = 1.000). One-unit increases in the HSP-27 expression level and BAP1 expression loss were significantly related to 1.375- and 7.855-fold increases in the risk of metastasis, respectively (P = 0.007 and P = 0.017).

CONCLUSION

HSP-27 and BAP1 are considered to be associated with metastasis, indicating these proteins as potential treatment targets in metastatic uveal melanoma.

C-C Chemokine Receptor 7 in Cancer

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

Non-invasive detection and complementary diagnosis of liver metastases via chemokine receptor 4 imaging

Noninvasive detection of early-stage liver metastases from different primary cancers is a pressing unmet medical need. The lack of both molecular biomarkers and the sensitive imaging methodology makes the detection challenging. In this study, we observed the elevated expression of chemokine receptor 4 (CXCR4) in uveal melanoma (UM) patient liver tissues, and high CXCR4 expression in liver metastases of UM murine models, regardless of the expression levels in the primary tumors. Based on these findings, we identified CXCR4 as an imaging biomarker and exploited a CXCR4-targeted MRI contrast agent ProCA32.CXCR4 for molecular MRI imaging. ProCA32.CXCR4 has strong CXCR4 binding affinity, high metal selectivity, and r1 and r2 relaxivities, which enables the sensitive detection of liver micrometastases. The MRI imaging capacity for detecting liver metastases was demonstrated in three UM models and one ovarian cancer model. The imaging results were validated by histological and immunohistochemical analysis. ProCA32.CXCR4 has strong potential clinical application for non-invasive diagnosis of liver metastases.

Novel Prognostic Immunohistochemical Markers in Uveal Melanoma-Literature Review

Simple Summary

The following study provides an overview of the English-language literature on the search for new prognostic factors for uveal melanoma. Uveal melanoma is the most common primary intraocular tumor in adults, and although it is a relatively rare disease, it poses a significant health problem. About half of the patients develop distant metastases, and unfortunately there are currently no effective treatments for the disease at such an advanced stage. The search for new prognostic factors is important to understand the biology of the disease and to be able to monitor patients more effectively. At the same time, it creates an opportunity to find new therapeutic targets. We focused our attention on immunohistochemical research because it is a widely used method, relatively cheap, technically simple, and gives reproducible results. The analysis of this study will enable other researchers to verify their research plans and may also be a source of inspiration for creating new ones.

Abstract

Uveal melanoma is the most common primary intraocular neoplasm in adults. As there are currently no effective methods of treating the disease in the metastatic stage, there is a need to search for new prognostic factors that would enable a reliable assessment of the patient’s condition and constitute a possible therapeutic target. In this review, we have prepared the results of English-language studies on new prognostic factors determined with immunohistochemical methods. We found 64 articles in which the expression of various proteins was associated in a statistically significant manner with the histopathological and clinical prognostic factors identified by AJCC. The results of our work clearly show that the biology of uveal melanoma is extraordinarily complex. Numerous studies have shed new light on the complexity of the processes involved in the development of this cancer. Moreover, a careful analysis of the expression of individual proteins may allow the identification of homogeneous groups of patients requiring different treatment regimens.

CCL27 Signaling in the Tumor Microenvironment

Chemokines are a group of small proteins which play an important role in leukocyte migration and invasion. They are also involved in the cellular proliferation and migration of tumor cells.Chemokine CCL27 (cutaneous T cell-attracting chemokine, CTACK) is mainly expressed by keratinocytes of the normal epidermis. It is well known that this chemokine plays an important role in several inflammatory diseases of the skin, such as atopic dermatitis, contact dermatitis, and psoriasis. Moreover, several studies have shown an association between CCL27 expression and a variety of neoplasms including skin cancer.In this chapter, we address the role of chemokine CCL27 in the tumor microenvironment in the most relevant cancers of the skin and other anatomical locations. We also make a brief comment on future perspectives and the potential relation of CCL27 with different immunotherapeutic modalities.

Conjunctival Melanoma: Update on Genetics, Epigenetics and Targeted Molecular and Immune-Based Therapies

Purpose

To present the molecular mechanisms involved in the pathogenesis of conjunctival melanoma (CM) and review the existing literature on targeted molecular inhibitors as well as immune checkpoint inhibitors for the management of locally advanced and metastatic disease.

Methods

A comprehensive review of the literature was performed using the keywords "conjunctival melanoma", "immune checkpoint inhibitors", "BRAF inhibitors", "MEK inhibitors", "CTLA4 inhibitors", "PD1 inhibitors", "c-KIT mutations", "BRAF mutations", "NRAS mutations", "dabrafenib", "trametinib", "vemurafenib", "ipilimumab", "pembrolizumab", and "nivolumab". A total of 250 articles were reviewed and 120 were included in this report.

Results

Mutations of mediators in the MAP kinase pathway, such as RAS, BRAF, MEK and ERK, and mutations of the PI3K/AKT/mTOR pathway play a major role in the pathogenesis of conjunctival melanoma. In addition, alterations of c-KIT, NF1, TERT, chemokine receptors as well as chromosomal copy number alterations and micro RNAs are thought to have a causative association with CM development. Targeted molecular inhibitors, such as BRAF and MEK inhibitors, are currently being implemented in the therapy of BRAF-mutated CM. Furthermore, immune checkpoint PD-1 and CTLA4 inhibitors with favorable clinical outcomes in the treatment of cutaneous melanoma have increased recurrence-free survival and reduced metastatic spread in CM cases.

Conclusion

The complex molecular mechanisms that contribute to the development of CM can be targeted both by molecular inhibitors of oncogenic pathways as well as immune checkpoint inhibitors in order to halt progression of the disease and increase survival.

Uveal melanoma pathobiology: Metastasis to the liver

Uveal melanoma (UM) is a type of intraocular tumor with a propensity to disseminate to the liver. Despite the identification of the early driver mutations during the development of the pathology, the process of UM metastasis is still not fully comprehended. A better understanding of the genetic, molecular, and environmental factors participating to its spread and metastatic outgrowth could provide additional approaches for UM treatment. In this review, we will discuss the advances made towards the understanding of the pathogenesis of metastatic UM, summarize the current and prospective treatments, and introduce some of the ongoing research in this field.

Molecular imaging of extracellular matrix proteins with targeted probes using magnetic resonance imaging

The extracellular matrix (ECM) consists of proteins and carbohydrates that supports different biological structures and processes such as tissue development, elasticity, and preservation of organ structure. Diseases involving inflammation, fibrosis, tumor invasion, and injury are all attributed to the transition of the ECM from homeostasis to remodeling, which can significantly change the biochemical and biomechanical features of ECM components. While contrast agents have played an indispensable role in facilitating clinical diagnosis of diseases using magnetic resonance imaging (MRI), there is a strong need to develop novel biomarker-targeted imaging probes for in vivo visualization of biological processes and pathological alterations at a cellular and molecular level, for both early diagnosis and monitoring drug treatment. Herein, we will first review the pathological accumulation and characterization of ECM proteins recognized as important molecular features of diseases. Developments in MRI probes targeting ECM proteins such as collagen, fibronectin, and elastin via conjugation of existing contrast agents to targeting moieties and their applications to various diseases, are also reviewed. We have also reviewed our progress in the development of collagen-targeted protein MRI contrast agent with significant improvement in relaxivity and metal binding specificity, and their applications in early detection of fibrosis and metastatic cancer. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Biology-Inspired Nanomaterials > Peptide-Based Structures Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.

Chemokine receptor 4 targeted protein MRI contrast agent for early detection of liver metastases

Liver metastases often progress from primary cancers including uveal melanoma (UM), breast, and colon cancer. Molecular biomarker imaging is a new non-invasive approach for detecting early stage tumors. Here, we report the elevated expression of chemokine receptor 4 (CXCR4) in liver metastases in UM patients and metastatic UM mouse models, and development of a CXCR4-targeted MRI contrast agent, ProCA32.CXCR4, for sensitive MRI detection of UM liver metastases. ProCA32.CXCR4 exhibits high relaxivities (r ₁ = 30.9 mM^-1 s^-1, r ₂ = 43.2 mM^-1 s^-1, 1.5 T; r ₁ = 23.5 mM^-1 s^-1, r ₂ = 98.6 mM^-1 s^-1, 7.0 T), strong CXCR4 binding (K _d = 1.10 ± 0.18 μM), CXCR4 molecular imaging capability in metastatic and intrahepatic xenotransplantation UM mouse models. ProCA32.CXCR4 enables detecting UM liver metastases as small as 0.1 mm³. Further development of the CXCR4-targeted imaging agent should have strong translation potential for early detection, surveillance, and treatment stratification of liver metastases patients.

Chemokine Receptor Expression Pattern Correlates to Progression of Conjunctival Melanocytic Lesions

Purpose

Chemokines play a role in the progression and metastatic spread of both cutaneous and uveal melanomas. The aim of this study was to examine the prognostic value of expression of chemokine receptors CCR7, CXCR4, and CCR10 in conjunctival melanocytic lesions.

Methods

In total, 44 conjunctival nevi, 21 cases of primary acquired melanosis (PAM) with atypia and 35 conjunctival melanomas, were included. After immunohistochemical staining for CCR7, CXCR4, and CCR10 the immunoreactive score (IRS) was determined. The findings were correlated for association with melanoma and development of metastasis. For mechanistic evaluation, we used a mouse melanoma metastasis model using two human conjunctival melanoma cell lines, CM2005.1 and CRMM1.

Results

All tested chemokines showed a significantly higher expression in conjunctival melanoma than conjunctival nevi. There was a statistically significant difference between the IRS in nevi and PAM with atypia for nuclear IRS in CCR10 (P = 0.03) and both nuclear and cytoplasmic IRS in CXCR4 (P < 0.01 and P = 0.03, respectively); this was also true evaluating the groups PAM with atypia and melanoma all together (P < 0.01). Furthermore, a trend for lower IRS was seen in cases of melanoma without metastasis, with a suggestive pattern of a higher IRS in cases that did develop metastases, supported for CXCR4 using the mouse melanoma metastasis model.

Conclusions

Expression of specific chemokines changes during the progression and metastatic spread of conjunctival melanocytic lesions. Differential chemokine profiles may hold prognostic value for patients with conjunctival melanomas and might be considered as a therapeutic target.

Uveal Versus Cutaneous Melanoma; Same Origin, Very Distinct Tumor Types

Here, we critically evaluated the knowledge on cutaneous melanoma (CM) and uveal melanoma (UM). Both cancer types derive from melanocytes that share the same embryonic origin and display the same cellular function. Despite their common origin, both CM and UM display extreme differences in their genetic alterations and biological behavior. We discuss the differences in genetic alterations, metastatic routes, tumor biology, and tumor-host interactions in the context of their clinical responses to targeted- and immunotherapy.

High expression of CCR5 in melanoma enhances epithelial-mesenchymal transition and metastasis via TGFβ1

Chemokine receptors are highly expressed in various cancers and play crucial roles in tumor progression. However, their expression patterns and functions in melanoma are unclear. The present study aimed to identify the chemokine receptors that play critical roles in melanoma progression and unravel the underlying molecular mechanisms. We found that CCR5 was more abundant in melanoma cells than normal cells and was positively associated with tumor malignancy in clinical patients. Animal experiments suggested that CCR5 deficiency in B16/F10 or A375 cells suppressed primary tumor growth and lung metastasis, whereas CCR5 overexpression in B16/F0 cells enhanced primary tumor growth and lung metastasis. CCR5 played a critical role in proliferation and migration of melanoma cells in vitro. Importantly, CCR5 was required for maintenance of the mesenchymal phenotype of metastatic melanoma cells. Mechanistically, CCR5 positively regulated expression of TGFβ1, which in turn induced epithelial-mesenchymal transition and migration via PI3K/AKT/GSK3β signaling. Collectively, our results establish a critical role of CCR5 expressed by melanoma cells in cancer progression and reveal the novel mechanisms controlling this process, which suggests the prognostic value of CCR5 in melanoma patients and provides novel insights into CCR5-targeted strategies for melanoma treatment. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

New Era in the Management of Melanoma Brain Metastases

The remarkable advances in the systemic therapy of metastatic melanoma have now extended the 1-year overall survival rate from 25% to nearing 85%. Systemic treatment in the form of BRAF-targeted therapy and immunotherapy is slowly but surely proving its efficacy in the treatment of metatstatic brain metastases (MBM). Single-agent BRAF inhibitors provide an intracranial response rate of 25% to 40%, whereas the combination of BRAFi/MEKi leads to responses in up to 58%. However, the durability of responses induced by BRAFi/MEKi seems to be even shorter than in extracranial disease. On the other hand, single-agent ipilimumab provides comparable clinical benefit in MBMs as it does in extracranial metastases. Single-agent PD-1 anitbodies induce response rates of approximately 20%, and those responses appear durable. Similarly the combination of CTLA-4+ PD-1 antibodies induces durable responses at an impressive rate of 55% and is safe to administer. Although the local treatment approaches with radiation and surgery remain important and are critically needed in the management of MBM, systemic therapy offers a new dimension that can augment the impact of those therapies and come at a potentially lower cost of neurocognitive impairment. Considerations for combining those modalities are direly needed, in addition to considering novel systemic combinations that target mechanisms specific to MBM. In this report, we will discuss the underlying biology of melanoma brain metastases, the clinical outcomes from recent clinical trials of targeted and immunotherapy, and their impact on clinical practice in the context of existing local therapeutic modalities.

Digital PCR-Based T-cell Quantification-Assisted Deconvolution of the Microenvironment Reveals that Activated Macrophages Drive Tumor Inflammation in Uveal Melanoma

Uveal melanoma progression can be predicted by gene expression profiles enabling a clear subdivision between tumors with a good (class I) and a poor (class II) prognosis. Poor prognosis uveal melanoma can be subdivided by expression of immune-related genes; however, it is unclear whether this subclassification is justified; therefore, T cells in uveal melanoma specimens were quantified using a digital PCR approach. Absolute T-cell quantification revealed that T-cell influx is present in all uveal melanomas associated with a poor prognosis. However, this infiltrate is only accompanied by differential immune-related gene expression profiles in uveal melanoma with the highest T-cell infiltrate. Molecular deconvolution of the immune profile revealed that a large proportion of the T-cell-related gene expression signature does not originate from lymphocytes but is derived from other immune cells, especially macrophages. Expression of the lymphocyte-homing chemokine CXCL10 by activated macrophages correlated with T-cell infiltration and thereby explains the correlation of T-cell numbers and macrophages. This was validated by in situ analysis of CXCL10 in uveal melanoma tissue with high T-cell counts. Surprisingly, CXCL10 or any of the other genes in the activated macrophage-cluster was correlated with reduced survival due to uveal melanoma metastasis. This effect was independent of the T-cell infiltrate, which reveals a role for activated macrophages in metastasis formation independent of their role in tumor inflammation. IMPLICATIONS: The current report uses an innovative digital PCR method to study the immune environment and demonstrates that absolute T-cell quantification and expression profiles can dissect disparate immune components.

Privileged portal metastasis of hepatocellular carcinoma in light of the coevolution of a visceral portal system and liver in the chordate lineage: a search for therapeutic targets

Hepatocellular carcinoma (HCC) disseminates systemically, but metastases occur in distant organs only in minority of patients, whereas HCC routinely metastasizes to liver and its vessels. HCC cells disseminate via hepatic veins, but portal veins are affected by metastasis more frequently than are hepatic veins, and correlates with poor prognosis. In this review, I suggest that privileged HCC portal metastasis occurs because of high levels of pancreatic family hormones and growth factors (PHGFs) in the portal blood. The analysis suggests that the appearance of the portal system carrying PHGFs in the evolution of invertebrate chordate (Amphioxus) led to the evolution of the liver in vertebrate; given that the portal pattern of HCC metastasis and selection of more-aggressive clones are PHGF dependent, PHGFs and their ligands constitute therapeutic targets.

The role of lymphangiogenesis and angiogenesis in tumor metastasis

BACKGROUND

Metastasis is the main cause of mortality in cancer patients. Two major routes of cancer cell spread are currently being recognized: dissemination via blood vessels (hematogenous spread) and dissemination via the lymphatic system (lymphogenous spread). Here, our current knowledge on the role of both blood and lymphatic vessels in cancer cell metastasis is summarized. In addition, I will discuss why cancer cells select one or both of the two routes to disseminate and I will provide a short description of the passive and active models of intravasation. Finally, lymphatic vessel density (LVD), blood vessel density (BVD), interstitial fluid pressure (IFP) and tumor hypoxia, as well as regional lymph node metastasis and the recently discovered primo vascular system (PVS) will be highlighted as important factors influencing tumor cell motility and spread and, ultimately, clinical outcome.

CONCLUSIONS

Lymphangiogenesis and angiogenesis are important phenomena involved in the spread of cancer cells and they are associated with a poor prognosis. It is anticipated that new discoveries and advancing knowledge on these phenomena will allow an improvement in the treatment of cancer patients.

Therapeutic Efficacy of Cancer Stem Cell Vaccines in the Adjuvant Setting

Dendritic cell (DC)-based vaccine strategies aimed at targeting cancer stem-like cells (CSC) may be most efficacious if deployed in the adjuvant setting. In this study, we offer preclinical evidence that this is the case for a CSC-DC vaccine as tested in murine models of SCC7 squamous cell cancer and D5 melanoma. Vaccination of mice with an ALDH(high) SCC7 CSC-DC vaccine after surgical excision of established SCC7 tumors reduced local tumor relapse and prolonged host survival. This effect was augmented significantly by simultaneous administration of anti-PD-L1, an immune checkpoint inhibitor. In the minimal disease setting of D5 melanoma, treatment of mice with ALDH(high) CSC-DC vaccination inhibited primary tumor growth, reduced spontaneous lung metastases, and increased host survival. In this setting, CCR10 and its ligands were downregulated on ALDH(high) D5 CSCs and in lung tissues, respectively, after vaccination with ALDH(high) D5 CSC-DC. RNAi-mediated attenuation of CCR10 blocked tumor cell migration in vitro and metastasis in vivo T cells harvested from mice vaccinated with ALDH(high) D5 CSC-DC selectively killed ALDH(high) D5 CSCs, with additional evidence of humoral immunologic engagement and a reduction in ALDH(high) cells in residual tumors. Overall, our results offered a preclinical proof of concept for the use of ALDH(high) CSC-DC vaccines in the adjuvant setting to more effectively limit local tumor recurrence and spontaneous pulmonary metastasis, as compared with traditional DC vaccines, with increased host survival further accentuated by simultaneous PD-L1 blockade. Cancer Res; 76(16); 4661-72. ©2016 AACR.

Uveal Melanoma: Current Trends in Diagnosis and Management

Uveal melanoma, which is the most common primary intraocular malignancy in adults, arises from melanocytes within the iris, ciliary body and choroid. The diagnosis is based principally on clinical examination of the tumor with biomicroscopy and indirect ophthalmoscopy and confirmed by diagnostic techniques such as ultrasonography, fundus fluorescein angiography and optical coherence tomography. The clinical diagnosis of posterior uveal melanomas can be made when the classical appearance of a pigmented dome-shaped mass is detected on dilated fundus exam. Uveal melanomas classically show low to medium reflectivity on A-scan ultrasonography and on B-scan ultrasonography the tumor appears as a hyperechoic, acoustically hollow intraocular mass. Management of a suspicious pigmented lesion is determined by its risk factors of transforming into a choroidal melanoma, such as documentation of growth, thickness greater than 2 mm, presence of subretinal fluid, symptoms and orange pigment, margin within 3 mm of the optic disc, and absence of halo and drusen. Advances in the diagnosis and local and systemic treatment of uveal melanoma have caused a shift from enucleation to eye-conserving treatment modalities including transpupillary thermotherapy and radiotherapy over the past few decades. Prognosis can be most accurately predicted by genetic profiling of fine needle aspiration biopsy of the tumor before the treatment, and high-risk patients can now be identified for clinical trials that may lead to target-based therapies for metastatic disease and adjuvant therapy which aims to prevent metastatic disease.

A comprehensive characterization of cell cultures and xenografts derived from a human verrucous penile carcinoma

This study aimed to establish and characterize primary cell cultures and xenografts derived from penile carcinoma (PeCa) in order to provide experimental models for cellular processes and efficacy of new treatments. A verrucous squamous cell carcinoma (VSCC) was macrodissected, dissociated, and cultivated in KSFM/DF12 medium. Cell cultures were evaluated at passage 5 (P5) using migration and invasion assays and were serially propagated, in vivo, in BALB/c nude mice until passage 3 (X1-X3). Immunophenotypic characterization of cultures and xenografts was performed. Genomic (CytoScan HD, Affymetrix) and transcriptomic profiles (HTA 2.0 platform, Affymetrix) for VSCC, cell cultures, and xenografts were assessed. P5 cells were able to migrate, invade the Matrigel, and produce tumors in immunodeficient mice, demonstrating their malignant potential. The xenografts unexpectedly presented a sarcomatoid-like carcinoma phenotype. Genomic analysis revealed a high similarity between the VSCC and tumor-derived xenograft, confirming its xenograft origin. Interestingly, a subpopulation of P5 cells presented stem cell-related markers (CD44(+)CD24(-) and ALDH1(high)) and sphere-forming capacity, suggesting their potential xenograft origin. Cell cultures and xenografts retained the genomic alterations present in the parental tumor. Compared to VSCC, differentially expressed transcripts detected in all experimental conditions were associated with cellular morphology, movement, and metabolism and organization pathways. Malignant cell cultures and xenografts derived from a verrucous penile carcinoma were established and fully characterized. Nevertheless, xenograft PeCa models must be used with caution, taking into consideration the selection of specific cell populations and anatomical sites for cell/tumor implantation.

Lymphangiogenic and Chemotactic Factors in Conjunctival Melanoma

PURPOSE

The aim of this study was to evaluate expression patterns of known lymphangiogenic growth factors and chemokines in conjunctival melanoma, and to describe patterns of lymphatic vessel growth in these tumors.

METHODS

This was a retrospective chart review comprising 5 participants (6 tumor specimens) and the main outcome measures were expression of growth factors, chemokines, and their receptors known to be important in tumor lymphangiogenesis as well as patterns of lymphatic vessel growth on immunohistochemical sections.

RESULTS

Tumor cells in all specimens expressed lymphangiogenic growth factors VEGFC, VEGFD, and their receptor VEGFR3. Chemotactic factors CXCL12 and CCL21 and their receptors, CXCR4 and CCL21, were also expressed in tumor cells and lymphatic endothelial cells. Staining was most intense for these proteins at the invasive tumor edge, suggesting increased lymphangiogenic activity at this location. In addition, lymphatic vessels clustered near the invasive edge of the tumors.

CONCLUSIONS

VEGFC, VEGFD, and VEGR3 are diffusely expressed by conjunctival melanoma cells, most intensely at the invasive tumor edge. CXCL12, CXCR4, CCL21, and CCR7 were also most intensely expressed at the invasive edge, where the highest density of lymphatic vessels was also observed. These expression patterns suggest that these mediators of tumor-associated lymphangiogenesis warrant further investigation as potential therapeutic targets in conjunctival melanoma.

Therapeutic Lymphoid Organogenesis in the Tumor Microenvironment

The inflammatory status of the tumor microenvironment (TME) has been heavily investigated in recent years. Chemokine- and cytokine-signaling pathways such as CCR7, CXCR5, lymphotoxin, and IL-36, which are involved in the generation of secondary lymphoid organs and effector immune responses, are now recognized as having value both as prognostic factors and as immunomodulatory therapeutics in the context of cancer. Furthermore, when produced in the TME, these mediators have been shown to promote the recruitment of immune cells, including T cells, B cells, dendritic cells (DCs), and other specialized immune cell subsets such as follicular DCs and T follicular helper cells, in association with the formation of "tertiary" lymphoid structures (TLSs) within or adjacent to sites of disease. Although TLSs are composed of a heterogeneous collection of immune cell types, whose composition differs based on cancer subtype, the qualitative presence of TLSs has been shown to represent a biomarker of good prognosis for cancer patients. A comprehensive understanding of the role each of these pathways plays within the TME may support the rational design of future immunotherapies to selectively promote/bolster TLS formation and function, leading to improved clinical outcomes across the vast range of solid cancer types.

Cancer stem cell vaccine inhibits metastases of primary tumors and induces humoral immune responses against cancer stem cells

The inability to target cancer stem cells (CSC) may be a significant factor contributing to treatment failure. We have developed a strategy to target the CSC populations in melanoma and squamous cell carcinoma using CSC lysate-pulsed dendritic cells (DCs). The CSC-DC vaccine was administered in the adjuvant setting after localized radiation therapy of established tumors. Using mouse models we demonstrated that DCs pulsed with CSCs enriched by virtue of their expression of the CSC marker ALDH (termed CSC-DC) significantly inhibited tumor growth, reduced development of pulmonary metastases and prolonged survival. The effect was associated with downregulation of chemokine (C-C motif) receptors CCR7 and CCR10 in tumor cells and decreased expression of the chemokine (C-C motif) ligands CCL21, CCL27 and CCL28 in lung tissue. The CSC-DC vaccine significantly reduced ALDH^high CSC frequency in primary tumors. Direct targeting of CSCs was demonstrated by the specific binding of IgG produced by ALDH^high CSC-DC vaccine-primed B cells to ALDH^high CSCs, resulting in lysis of these target CSCs in the presence of complement. These data suggest that the CSC-DC vaccine approach may be useful in the adjuvant setting where local and systemic relapse are high after conventional treatment of cancers.

Role of Tertiary Lymphoid Structures (TLS) in Anti-Tumor Immunity: Potential Tumor-Induced Cytokines/Chemokines that Regulate TLS Formation in Epithelial-Derived Cancers

Following the successes of monoclonal antibody immunotherapies (trastuzumab (Herceptin^®) and rituximab (Rituxan^®)) and the first approved cancer vaccine, Provenge^® (sipuleucel-T), investigations into the immune system and how it can be modified by a tumor has become an exciting and promising new field of cancer research. Dozens of clinical trials for new antibodies, cancer and adjuvant vaccines, and autologous T and dendritic cell transfers are ongoing in hopes of identifying ways to re-awaken the immune system and force an anti-tumor response. To date, however, few consistent, reproducible, or clinically-relevant effects have been shown using vaccine or autologous cell transfers due in part to the fact that the immunosuppressive mechanisms of the tumor have not been overcome. Much of the research focus has been on re-activating or priming cytotoxic T cells to recognize tumor, in some cases completely disregarding the potential roles that B cells play in immune surveillance or how a solid tumor should be treated to maximize immunogenicity. Here, we will summarize what is currently known about the induction or evasion of humoral immunity via tumor-induced cytokine/chemokine expression and how formation of tertiary lymphoid structures (TLS) within the tumor microenvironment may be used to enhance immunotherapy response.

Clinicopathological characteristics of vascular endothelial growth factor expression in uveal melanoma: A meta-analysis

Angiogenesis is a potential prognostic factor that has been extensively investigated in patients with uveal melanoma (UM). Vascular endothelial growth factor (VEGF) expression is crucial in angiogenesis. However, there have been conflicting data regarding the clinicopathological data in UM. A meta-analysis was performed of all the germane literature to assess the clinicopathological characteristics of VEGF expression by combining separately estimated odds ratio (OR) values. Our combined results demonstrated that, according to the available studies, the expression of VEGF in UM was significantly higher compared to normal tissue [338 patients and 99 controls; OR=16.15, 95% confidence interval (CI): 8.65-30.12, P<0.00001]. When stratifying the studies by age (315 patients; OR=2.08, 95% CI: 1.19-3.62, P=0.01), cell type (423 patients; OR=0.54, 95% CI: 0.32-0.90, P=0.02), tumor size (222 patients; OR=0.30, 95% CI: 0.14-0.68, P=0.004) and scleral invasion (248 patients; OR=0.34, 95% CI: 0.15-0.78, P=0.01), significant clinicopathological information was provided. Our results indicated that VEGF expression in UM patients was significantly higher compared to that observed in controls. It was also significantly higher in patients who presented with scleral invasion and those who were aged <50 years. In addition, VEGF expression was higher in mixed-cell type and epithelioid-cell type UM and in patients with large-sized tumors.