Tumor-Associated Macrophages in the Cutaneous SCC Microenvironment Are Heterogeneously Activated

Macrophages in T cell/histiocyte rich large B cell lymphoma strongly express metal-binding proteins and show a bi-activated phenotype

Abundant macrophage infiltration in tumors often correlates with a poor prognosis. T cell/histiocyte rich large B cell lymphoma (THRLBCL) is a distinct aggressive B cell lymphoma entity showing a high macrophage content. To further elucidate the role of tumor-associated macrophages in THRLBCL, we performed gene expression profiling of microdissected histiocyte subsets of THRLBCL, nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), Piringer lymphadenitis, sarcoidosis, nonspecific lymphadenitis and monocytes from peripheral blood. In a supervised principal component analysis, histiocytes from THRLBCL were most closely related to epithelioid cells from NLPHL, with both types of cells expressing genes related to proinflammatory and regulatory macrophage activity. Moreover, histiocytes from THRLBCL strongly expressed metal-binding proteins like MT2A, by which histiocytes of THRLBCL can be distinguished from the other histiocyte subsets investigated. Interestingly, the validation at the protein level showed a strong expression of TXN, CXCL9, MT2A and SOD2 not only in macrophages of THRLBCL but also in the tumor cells of NLPHL and classical Hodgkin lymphoma (cHL). Overall, the present findings indicate that macrophages in the microenvironment of THRLBCL have acquired a distinct gene expression pattern that is characterized by a mixed M1/M2 phenotype and a strong expression of several metal binding proteins. The microenvironments in NLPHL and THRLBCL appear to have a similar influence on the macrophage phenotype. The high expression of metal binding proteins in histiocytes of THRLBCL may be diagnostically useful, but a potential pathophysiological role remains to be identified.

Increased Tc22 and Treg/CD8 ratio contribute to aggressive growth of transplant associated squamous cell carcinoma

Immune suppressed organ transplant recipients suffer increased morbidity and mortality from primary cutaneous SCC. We studied tumor microenvironment in transplant-associated SCC (TSCC), immune-competent SCC and normal skin by IHC, IF and RT-PCR on surgical discard. We determined T cell polarization in TSCC and SCC by intracellular cytokine staining of T cell crawl outs from human skin explants. We studied the effects of IL-22, an inducer of keratinocyte proliferation, on SCC proliferation in vitro. SCC and TSCC are both associated with significantly higher numbers of CD3(+) and CD8(+) T cells compared to normal skin. TSCC showed a higher proportion of Foxp3(+) T regs to CD8(+) T cells compared to SCC and a lower percentage of IFN-γ producing CD4(+) T cells. TSCC, however, had a higher percentage of IL-22 producing CD8(+) T cells compared to SCC. TSCC showed more diffuse Ki67 and IL-22 receptor (IL-22R) expression by IHC. IL-22 induced SCC proliferation in vitro despite serum starvation. Diminished cytotoxic T cell function in TSCC due to decreased CD8/T-reg ratio may permit tumor progression. Increased IL-22 and IL-22R expression could accelerate tumor growth in transplant patients. IL-22 may be an attractive candidate for targeted therapy of SCC without endangering allograft survival.

Tumor microenvironment profoundly modifies functional status of macrophages: peritoneal and tumor-associated macrophages are two very different subpopulations

Macrophages are key players in the inflammatory response. In this study, we tested the hypothesis that although all macrophage subpopulations in tumor hosts are affected by the disease, it is the close proximity to the tumor that induces major alterations in these cells. We compared tumor-associated macrophages (TAMs) with peritoneal macrophages from mice bearing D1-DMBA-3 mammary tumors (T-PEMs). Our results show that TAMs downregulate IL-12p70 but upregulate IL-12p40, IL-23, IL-6 and IL-10. Some NFκB and C/EBP transcription factors family members are decreased in TAMs; however NFκBp50 homodimers, STAT1/pSTAT1 and STAT3/pSTAT3 are overexpressed. Furthermore, while TAMs block T-cell proliferation and are more prone to apoptosis compared to T-PEMs, both types of macrophages have an impaired phagocytic capacity. Moreover, TAMs constitutively express iNOS and produce nitric oxide but do not express arginase and are Gr-1(high) and CD11b(low). Collectively, our analysis of two spatially distinct macrophage subpopulations in tumor-bearing mice revealed that the tumor modulates them differently into two molecularly and functionally dissimilar macrophage subpopulations.

Potential use of bisphosphonates in invasive extramammary Paget's disease: an immunohistochemical Investigation

Invasive extramammary Paget's disease (EMPD) is relatively rare and is reported to be highly metastatic to lymph nodes or even other organs, including bone. Histologically, EMPD shows significant numbers of lymphocytes around the tumor mass, suggesting the possible development of novel immunomodulatory therapy for EMPD by targeting these infiltrating lymphocytes. Previously, bisphosphonates (BPs) were administered for the treatment of malignancy, especially osteolytic bone disease. Recent reports also suggested that BPs might have a direct antitumor effect through several pathways beyond their beneficial effect on bone metastasis. Among them, the abrogation of immunosuppressive cells, myeloid derived suppressor cells (MDSC), by BPs might be one of the optimal methods to induce an antitumor immune response both locally and at sites remote from the tumor. In this study, we employed immunohistochemical staining for immunosuppressive macrophages and cytotoxic T cells in the lesional skin of patients with noninvasive EMPD and those with invasive EMPD.

Understanding dendritic cells and their role in cutaneous carcinoma and cancer immunotherapy

Dendritic cells (DC) represent a diverse group of professional antigen-presenting cells that serve to link the innate and adaptive immune systems. Their capacity to initiate a robust and antigen-specific immune response has made them the ideal candidates for cancer immunotherapies. To date, the clinical impact of DC immunotherapy has been limited, which may, in part, be explained by the complex nature of DC biology. Multiple distinct subsets of DCs have been identified in the skin, where they can be broadly subcategorized into epidermal Langerhans cells (LC), myeloid-derived dermal dendritic cells (mDC) and plasmacytoid dendritic cells (pDC). Each subset is functionally unique and may activate alternate branches of the immune system. This may be relevant for the treatment of squamous cell carcinoma, where we have shown that the tumor microenvironment may preferentially suppress the activity of mDCs, while LCs remain potent stimulators of immunity. Here, we provide an in depth analysis of DC biology, with a particular focus on skin DCs and their role in cutaneous carcinoma. We further explore the current approaches to DC immunotherapy and provide evidence for the targeting of LCs as a promising new strategy in the treatment of skin cancer.

CCL18 as an independent favorable prognostic biomarker in patients with colorectal cancer

BACKGROUND

CCL18 has been shown to have an important role in the progression of gastric and breast cancers. However, the prognostic value of CCL18 in colorectal cancer (CRC) remains unknown.

MATERIALS AND METHODS

We used immunohistochemistry to examine the expression of CCL18 in CRC patients. We applied both univariate and multivariate analysis to evaluate the prognostic value of CCL18 on CRC patients' survival. We used double staining to investigate the relationship between CCL18 and macrophages.

RESULTS

A total 371 CRC patient samples were enrolled in immunohistochemical analysis. According to our criteria, 118 samples (31.8%) showed a high CCL18 expression level. Clinicopathologic analysis revealed an association between the expression level of CCL18 and the preoperative carcino embryonic antigen level (P = 0.001), and the preoperative carbohydrate antigen 19-9 level (P = 0.003). Survival analysis and multivariate analysis revealed that CCL18 was an independent favorable prognostic factor in patients with CRC (P = 0.033). Double staining implied that CCL18 was expressed by macrophages.

CONCLUSIONS

A high CCL18 level might be an independent biomarker for predicting better survival of patients with CRC.

Association of the numbers of CD163(+) cells in lesional skin and serum levels of soluble CD163 with disease progression of cutaneous T cell lymphoma

BACKGROUND

Classically activated macrophages produce IL-12, IL-23, and TNF-α, whereas alternatively activated macrophages (M2 cells) produce IL-10 and express several receptors such as mannose receptor and CD163. Tumor-associated macrophages exhibit M2 phenotype, whose presence has been associated with poor prognosis in various tumors.

OBJECTIVES

To investigate distribution of CD163(+) cells in lesional skin and serum levels of soluble CD163 (sCD163) in patients with cutaneous T cell lymphoma (CTCL), atopic dermatitis (AD), or psoriasis.

METHODS

The numbers of CD163(+) and CD68(+) cells in lesional skin of CTCL, AD, or psoriasis, and in normal skin were examined by immunohistochemistry. Serum soluble CD163 (sCD163) levels were quantified by enzyme-linked immunosorbent assay.

RESULTS

The numbers of CD163(+) cells in lesional skin of CTCL, AD, or psoriasis were significantly larger than in normal skin. In CTCL, the numbers of CD163(+) or CD68(+) cells increased as more tumor cells infiltrated and they decreased after treatment with topical steroid and ultraviolet light. Moreover, CTCL patients with an increased number of CD163(+) cells showed worse prognosis. Serum sCD163 levels in patients with CTCL, AD, or psoriasis were significantly higher than those in normal controls. In CTCL patients, serum sCD163 levels significantly correlated with serum soluble interleukin-2 receptor and CCL17 levels. In AD patients, serum sCD163 levels correlated with serum IgE levels.

CONCLUSION

The numbers of CD163(+) cells in lesional skin and serum sCD163 levels were associated with disease progression of CTCL. Further study focusing on CD163(+) cells in CTCL lesional skin would be an interesting research field.

Claudin-1, claudin-2 and claudin-11 genes differentially associate with distinct types of anti-inflammatory macrophages in vitro and with parasite- and tumour-elicited macrophages in vivo

Macrophages altered by various Th2-associated and anti-inflammatory mediators--including IL-4 and IL-13 [inducing alternatively activated macrophages (AAMs)], IL-10 and TGF-β--were generically termed M2. However, markers that discriminate between AAMs and other M2 remain scarce. We previously described E-cadherin as a marker for AAMs, permitting these macrophages to fuse upon IL-4 stimulation. To identify novel potential contributors to macrophage fusion, we assessed the effect of IL-4 on other adherens and tight junction-associated components. We observed an induction of claudin-1 (Cldn1), Cldn2 and Cldn11 genes by IL-4 in different mouse macrophage populations. Extending our findings to other stimuli revealed Cldn1 as a mainly TGF-β-induced gene and showed that Cldn11 is predominantly associated with IL-4-induced AAMs. Cldn2 is upregulated by diverse stimuli and is not associated with a specific macrophage activation state in vitro. Interestingly, different claudin genes preferentially associate with M2 from distinct diseases. While Cldn11 is predominantly expressed in AAMs from helminth-infected mice, Cldn1 is the major macrophage claudin during chronic trypanosomiasis and Cldn2 dominates in tumour-associated macrophages. Overall, we identified Cldn1, Cldn2 and Cldn11 as genes that discriminate between diverse types of M2.

Integrating macrophages into organotypic co-cultures: a 3D in vitro model to study tumor-associated macrophages

Tumor progression is controlled by signals from cellular and extra-cellular microenvironment including stromal cells and the extracellular matrix. Consequently, three-dimensional in vitro tumor models are essential to study the interaction of tumor cells with their microenvironment appropriately in a biologically relevant manner. We have previously used organotypic co-cultures to analyze the malignant growth of human squamous cell carcinoma (SCC) cell lines on a stromal equivalent in vitro. In this model, SCC cell lines are grown on a collagen-I gel containing fibroblasts. Since macrophages play a critical role in the progression of many tumor types, we now have expanded this model by integrating macrophages into the collagen gel of these organotypic tumor co-cultures. This model was established as a murine and a human system of skin SCCs. The effect of macrophages on tumor progression depends on their polarization. We demonstrate that macrophage polarization in organotypic co-cultures can be modulated towards and M1 or an M2 phenotype by adding recombinant IFN-γ and LPS or IL-4 respectively to the growth medium. IL-4 stimulation of macrophage-containing cultures resulted in enhanced tumor cell invasion evidenced by degradation of the basement membrane, enhanced collagenolytic activity and increased MMP-2 and MMP-9. Interestingly, extended co-culture with tumor cells for three weeks resulted in spontaneous M2 polarization of macrophages without IL-4 treatment. Thus, we demonstrate that macrophages can be successfully integrated into organotypic co-cultures of murine or human skin SCCs and that this model can be exploited to analyze macrophage activation towards a tumor supporting phenotype.

Tumor-associated macrophages in pediatric classical Hodgkin lymphoma: association with Epstein-Barr virus, lymphocyte subsets, and prognostic impact

PURPOSE

Tumor-infiltrating macrophages are associated with adverse outcome in adult classical Hodgkin lymphoma (cHL). We have previously shown age-related changes in the lymphocyte composition of pediatric cHL. We therefore hypothesized that the number, function, and prognostic impact of macrophages in pediatric cHL would be different from adult cases.

EXPERIMENTAL DESIGN

We analyzed the number of macrophages and dendritic cells (DC) in the tumor microenvironment of pediatric cHL by immunohistochemistry. Results were analyzed in context of age, histologic characteristics, Epstein-Barr virus (EBV) status, clinical follow-up, and our previous study of T-cell populations in these cases.

RESULTS

One hundred cHL cases were studied, including 69% nodular sclerosis and 23% mixed cellularity cases. A total of 44.8% of cases were EBV-positive. Patients ≤10 years displayed more CD14(+) cells (P = 0.025). In comparison with nodular sclerosis, mixed cellularity was characterized by higher numbers of CD14(+), (P = 0.003) and CD163(+) cells (P = 0.027). EBV(+) cases exhibited higher numbers of CD14(+) (P < 0.0005), CD68(+) (P = 0.005), and CD163(+) cells (P = 0.02). CD68-positive cells did not display an effect on outcome. Worse overall survival was observed in cases with CD163/CD8 ratio ≥2 (P = 0.007). High numbers of CD163(+) cells were associated with worse progression-free survival (PFS; P = 0.015). Furthermore, high numbers of CD163(+) and granzyme B(+) cells were associated with worse PFS in EBV-negative (P = 0.005) but not in EBV-positive cases.

CONCLUSION

Our results suggest that macrophage composition in pediatric cHL is distinct from adults. Functional status of macrophages and their value as prognostic indicators in pediatric cHL may depend on EBV status.

Macrophage-tumor crosstalk: role of TAMR tyrosine kinase receptors and of their ligands

Ample clinical and preclinical evidence indicates that macrophages interact with tumor cells as well as with virtually all populations of host cells present in the tumor microenvironment. This crosstalk can strongly promote malignancy, but also has in principle the potential to inhibit tumor growth. Thus, it is of the utmost importance to improve our understanding of the mechanisms driving the pro- and antimalignant behavior of tumor-associated macrophages (TAMs) in order to develop better anticancer therapies. In this review, we discuss the biological consequences of reciprocal interactions between TAMs, cancer cells, endothelial cells, fibroblasts and other leukocyte subfractions within tumors. It was recently elucidated that tumors specifically educate macrophages to secrete growth arrest-specific gene 6 (Gas6), the common ligand of the Tyro3, Axl, Mer receptor (TAMR) family. In turn, Gas6 fosters tumor growth by promoting cancer cell proliferation. Therefore, the Gas6-TAMR axis might represent a novel target for disrupting tumor-macrophage crosstalk. We summarize here what is known about TAMR and their ligands in (human) cancer biology. In order to shed more light on the role of macrophages in human cancer, we additionally provide an overview of what is currently known about the prognostic impact of TAMs in human cancer.

Inducing healing-like human primary macrophage phenotypes by 3D hydrogel coated nanofibres

Immune cells are present in the blood and in resident tissues, and the nature of their reaction towards biomaterials is decisive for materials success or failure. Macrophages may for example be classically activated to trigger inflammation (M1), or alternatively activated which supports healing and vascularisation (M2). Here, we have generated 3D nanofibrous meshes in different porosities and precisely controlled surface chemistries comprising PLGA, hydrogel-coated protein repellant and protein repellant endowed with the bioactive peptide sequences GRGDS or GLF. We also prepared 2D substrates with corresponding surface chemistry for a systematic evaluation of primary human macrophage adhesion, migration, transcriptome expression, cytokine release and surface marker expression. Our data show that material morphology is a powerful means in biomaterial design to influence immune cell response. Flat substrates lead to an increased number of M2 classified CD163(+) macrophages. However, these M2 cells released large amounts of pro-inflammatory cytokines. In contrast, 3D nanofibres with corresponding surface chemistry yielded M1 classified 27E10(+) macrophages with a significantly increased release of pro-angiogenic chemokines and angiogenesis related molecules and a strong decrease of pro-inflammatory cytokines. We thus suggest that, for macrophages in contact with biomaterials, cytokine release is taken as main criterion instead of surface-markers for macrophage classifications.

Dermal mast cells affect the development of sunlight-induced skin tumours

Ultraviolet (UV) radiation contained in sunlight is considered a major risk in the induction of skin cancer. While mast cells are best known for their role in allergic responses, they have also been shown to play a crucial role in suppressing the anti-tumour immune response following UV exposure. Evidence is now emerging that UV may also trigger mast cell release of cutaneous tissue remodelling and pro-angiogenic factors. In this review, we will focus on the cellular and molecular mechanisms by which UV recruits and then activates mast cells to initiate and promote skin cancer development.

Identification and manipulation of tumor associated macrophages in human cancers

Evading immune destruction and tumor promoting inflammation are important hallmarks in the development of cancer. Macrophages are present in most human tumors and are often associated with bad prognosis. Tumor associated macrophages come in many functional flavors ranging from what is known as classically activated macrophages (M1) associated with acute inflammation and T-cell immunity to immune suppressive macrophages (M2) associated with the promotion of tumor growth. The role of these functionally different myeloid cells is extensively studied in mice tumor models but dissimilarities in markers and receptors make the direct translation to human cancer difficult. This review focuses on recent reports discriminating the type of infiltrating macrophages in human tumors and the environmental cues present that steer their differentiation. Finally, immunotherapeutic approaches to interfere in this process are discussed.

Tumor cells and tumor-associated macrophages: secreted proteins as potential targets for therapy

Inflammatory pathways, meant to defend the organism against infection and injury, as a byproduct, can promote an environment which favors tumor growth and metastasis. Tumor-associated macrophages (TAMs), which constitute a significant part of the tumor-infiltrating immune cells, have been linked to the growth, angiogenesis, and metastasis of a variety of cancers, most likely through polarization of TAMs to the M2 (alternative) phenotype. The interaction between tumor cells and macrophages provides opportunities for therapy. This paper will discuss secreted proteins as targets for intervention.

Roles of the immune system in skin cancer

Over the past several decades, there has been increasing interest in understanding the roles of the immune system in the development and progression of cancer. The importance of the immune system in human skin cancer has been long recognized based primarily upon the increased incidence of skin cancers in organ transplant recipients and mechanisms of ultraviolet (UV) radiation-mediated immunomodulation. In this review, we integrate multiple lines of evidence highlighting the roles of the immune system in skin cancer. First, we discuss the concepts of cancer immunosurveillance and immunoediting as they might relate to human skin cancers. We then describe the clinical and molecular mechanisms of skin cancer development and progression in the contexts of therapeutic immunosuppression in organ transplant recipients, viral oncogenesis, and UV radiation-induced immunomodulation with a primary focus on basal cell carcinoma and squamous cell carcinoma. The clinical evidence supporting expanding roles for immunotherapy is also described. Finally, we discuss recent research examining the functions of particular immune cell subsets in skin cancer and how they might contribute to both antitumour and protumour effects. A better understanding of the biological mechanisms of cancer immunosurveillance holds the promise of enabling better therapies.

Skin cancer in transplant recipients, out of the woods. Scientific retreat of the ITSCC and SCOPE

The International Transplant Skin Cancer Collaborative (ITSCC) is an organization of more than 300 members dedicated to the study and care of skin changes that develop in solid-organ transplant recipients. This group of medical and surgical dermatologists, transplant surgeons and basic science researchers was formed to better understand the basic science of transplant dermatology, and to work collaboratively to address the clinical challenges in this patient population. Transplant patients have an ∼100-fold increased risk of developing cutaneous squamous cell carcinoma than the general population and are also at an increased risk of developing basal cell carcinoma, melanoma, Merkel cell carcinoma and Kaposi's sarcoma. In October 2010, ITSCC and its European counterpart Skin Care in Organ Transplant Patients Europe (SCOPE) held a joint biennial 4-day scientific retreat in the woods near Essex, Massachusetts. In this meeting report we provide an up-to-date distillation of the novel findings presented in the 21 oral abstracts, at the tumor board and within the working groups.