Breast carcinoma cells promote the differentiation of CD34+ progenitors towards 2 different subpopulations of dendritic cells with CD1a(high)CD86(-)Langerin- and CD1a(+)CD86(+)Langerin+ phenotypes

Langerin-expressing dendritic cells in pulmonary immune-related diseases

Dendritic cells (DCs) are “frontline” immune cells dedicated to antigen presentation. They serve as an important bridge connecting innate and adaptive immunity, and express various receptors for antigen capture. DCs are divided into various subclasses according to their differential expression of cell surface receptors and different subclasses of DCs exhibit specific immunological characteristics. Exploring the common features of each sub-category has became the focus of many studies. There are certain amounts of DCs expressing langerin in airways and peripheral lungs while the precise mechanism by which langerin⁺ DCs drive pulmonary disease is unclear. Langerin-expressing DCs can be further subdivided into numerous subtypes based on the co-expressed receptors, but here, we identify commonalities across these subtypes that point to the major role of langerin. Better understanding is required to clarify key disease pathways and determine potential new therapeutic approaches.

Presence of Dendritic Cell Subsets in Sentinel Nodes of Breast Cancer Patients Is Related to Nodal Burden

BACKGROUND: Sentinel lymph nodes (SLNs) are both the first site where breast cancer (BC) metastases form and where anti-tumoral immunity develops. Despite being the most potent antigen-presenting cells, dendritic cells (DCs) located in a nodal tissue can both promote or suppress immune response against cancer in SLNs. METHODS: In SLNs excisions obtained from 123 invasive BC patients, we performed immunohistochemistry (IHC) for CD1a, CD1c, DC-LAMP, and DC-SIGN to identify different DCs populations. Then we investigated the numbers of DCs subsets in tumor-free, micrometastatic, and macrometastatic SLNs with the use of a light microscope. RESULTS: We observed that CD1c+ and DC-SIGN+ DCs were more numerous in SLNs with a larger tumor size. More abundant intratumoral DC-LAMP+ population was related to a higher number of metastatic lymph nodes. Conversely, more abundant CD1a+ DCs were associated with a decreasing nodal burden in SLNs and a lower number of involved lymph nodes. Moreover, densities of the investigated DC populations differed with respect to tumor grade, HER2 overexpression, hormone receptor status, and histologic type of BC. CONCLUSIONS: According to their subtype, DCs are associated with either lower or higher nodal burden in SLNs from invasive BC patients. These relationships appear to be dependent not only on the maturation state of DCs but also on the histological and biological characteristics of the tumor.

Myeloid Immune Cells CARrying a New Weapon Against Cancer

Chimeric antigen receptor (CAR) engineering for T cells and natural killer cells (NK) are now under clinical evaluation for the treatment of hematologic cancers. Although encouraging clinical results have been reported for hematologic diseases, pre-clinical studies in solid tumors have failed to prove the same effectiveness. Thus, there is a growing interest of the scientific community to find other immune cell candidate to express CAR for the treatment of solid tumors and other diseases. Mononuclear phagocytes may be the most adapted group of cells with potential to overcome the dense barrier imposed by solid tumors. In addition, intrinsic features of these cells, such as migration, phagocytic capability, release of soluble factors and adaptive immunity activation, could be further explored along with gene therapy approaches. Here, we discuss the elements that constitute the tumor microenvironment, the features and advantages of these cell subtypes and the latest studies using CAR-myeloid immune cells in solid tumor models.

Immune-Related Molecular Profiling of Thymoma With Myasthenia Gravis

Background: Approximately 50% of thymoma patients also show myasthenia gravis (MG), which is an autoimmune disease; however, the pathogenesis of MG-associated thymoma remains elusive. Our aim was to investigate immune-related lncRNA profiles of a set of candidate genes for better understanding of the molecular mechanism underlying the pathogenesis of thymoma with or without MG. Methods: Molecular profiles of thymoma with or without MG were downloaded from The Cancer Genome Atlas, and Pearson's correlation analysis was performed to identify immune-related lncRNAs. T test was used to examine the differential expression and differential methylation between thymoma patients with or without MG. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to predict the function of target genes of immune-related lncRNAs. Results: Analyses of the 87 thymoma samples with complete MG information revealed that 205 mRNAs and 56 lncRNAs showed up-regulated expression in thymoma with MG patients, while 458 mRNAs and 84 lncRNAs showed down-regulated expression. The methylation level of three immune-related lncRNAs (AP000787.1, AC004943.1, WT1-AS, FOXG1-AS1) was significantly decreased in thymoma tissues, and the methylation level of these immune-related lncRNAs (WT1-AS: Cor = 0.368, p < 0.001; FOXG1-AS1: Cor = 0.288, p < 0.01; AC004943.1: Cor = -0.236, p < 0.05) correlated with their expression. GO and KEGG pathway analysis revealed that targets of the immune-related lncRNA FOXG1-AS1 were enriched in small GTPase binding and herpes simplex virus 1 infection. Transcription coregulator activity and cell cycle were the most enriched pathways for targets of lncRNA AC004943.1. LncRNA WT1-AS targets were most enriched in actin binding and axon guidance. Conclusion: Our results revealed the immune-related molecular profiling of thymoma with MG and without MG and identified key pathways involved in the underlying molecular mechanism of thymoma-related MG. These findings provide insights for further research of potential markers for thymoma-related MG.

Multifaceted roles of CCL20 (C-C motif chemokine ligand 20): mechanisms and communication networks in breast cancer progression

Emerging studies have demonstrated notable roles of CCL20 in breast cancer progression. Based on these findings, CCL20 has become a potential therapeutic target for cancer immunotherapy. Accordingly, studies utilizing monoclonal antibodies to target CCL20 are currently being experimented. However, the existence of cytokine network in the tumor microenvironment collectively regulates tumor progression. Hence, a deeper understanding of the role of CCL20 and the underlying signaling pathways regulating the functions of CCL20 may provide a novel strategy for therapeutic interventions. This review provides the current knowledge on how CCL20 interacts with breast cancer cells to influence tumor progression via immunosuppression, angiogenesis, epithelial to mesenchymal transition, migration/invasion and chemoresistance. As a possible candidate biomarker, we also reviewed signal pathways and other factors in the tumor microenvironment regulating the tumor-promoting functions of CCL20.These new insights may be useful to design new potent and selective CCL20 inhibitors against breast cancer in the future.

CXCL9 secreted by tumor-associated dendritic cells up-regulates PD-L1 expression in bladder cancer cells by activating the CXCR3 signaling

Background

Tumor-associated dendritic cells (TADCs) can interact with tumor cells to suppress anti-tumor T cell immunity. However, there is no information on whether and how TADCs can modulate programmed death-ligand 1 (PD-L1) expression by cancer cells.

Methods

Human peripheral blood monocytes were induced for DCs and immature DCs were cultured alone, or co-cultured with bladder cancer T24 or control SV-HUC-1 cells, followed by stimulating with LPS for DC activation. The activation status of DCs was characterized by flow cytometry and allogenic T cell proliferation. The levels of chemokines in the supernatants of co-cultured DCs were measured by CBA-based flow cytometry. The impacts of CXCL9 on PD-L1, STAT3 and Akt expression and STAT3 and Akt phosphorylation in T24 cells were determined by flow cytometry and Western blot.

Results

Compared with the control DCs, TADCs exhibited immature phenotype and had significantly lower capacity to stimulate allogenic T cell proliferation, particularly in the presence of recombinant CXCL9. TADCs produced significantly higher levels of CXCL9, which enhanced PD-L1 expression in T24 cells. Pre-treatment with AMG487 abrogated the CXCL9-increased PD-L1 expression in T24 cells. Treatment with CXCL9 significantly enhanced STAT3 and Akt activation in T24 cells.

Conclusions

TADCs produced high levels of CXCL9 that increased PD-L1 expression in bladder cancer T24 cells by activating the CXCR3-related signaling. Our findings may shed new lights in understanding the regulatory roles of TADCs in inhibiting antitumor T cell responses and promoting tumor growth.

Functional Role of Dendritic Cell Subsets in Cancer Progression and Clinical Implications

Dendritic cells (DCs) constitute a complex network of cell subsets with common functions but also with many divergent aspects. All dendritic cell subsets share the ability to prime T cell response and to undergo a complex trafficking program related to their stage of maturation and function. For these reasons, dendritic cells are implicated in a large variety of both protective and detrimental immune responses, including a crucial role in promoting anti-tumor responses. Although cDC1s are the most potent subset in tumor antigen cross-presentation, they are not sufficient to induce full-strength anti-tumor cytotoxic T cell response and need close interaction and cooperativity with the other dendritic cell subsets, namely cDC2s and pDCs. This review will take into consideration different aspects of DC biology, including the functional role of dendritic cell subsets in both fostering and suppressing tumor growth, the mechanisms underlying their recruitment into the tumor microenvironment, as well as the prognostic value and the potentiality of dendritic cell therapeutic targeting. Understanding the specificity of dendritic cell subsets will allow to gain insights on role of these cells in pathological conditions and to design new selective promising therapeutic approaches.

CC chemokines are differentially expressed in Breast Cancer and are associated with disparity in overall survival

Despite recent advances, breast cancer (BrCa) still affects many women and the impact is disproportional in African Americans (AA) compared to European Americans (EA). Addressing socioeconomic and behavioral status has not been enough to reduce disparity, suggesting contribution of biological differences in BrCa disparity. Our laboratory was first to show involvement of CC chemokines in BrCa. In this study, using ONCOMINE, TCGA, bc-GenExMiner and KMplotter, we examined the association of CC chemokines in BrCa outcomes and disparity. We show over-expression of CCL5, -7, -11, -17, -20, -22 and -25 in BrCa tissues. High mRNA levels of CCL7, -8, -17, -20 and -25 predicted a decrease in overall survival (OS). CCL7 and CCL8 were associated with decreased relapse-free survival. Expression of CCL17 and CCL25 was associated with decreased OS in AA. In EA, CCL8 was associated with decreased OS. Expression of CCL5, -7, -8, -17, -20 and -25 was highest in TNBC. Expression of CCL11 and CCL22 was associated with HER2. CCL7, -8, -17, -20 and -25 were elevated in AAs. In conclusion, our analysis suggests significant association of CC-chemokines in BrCa progression, OS and disparate disease outcome in AA compared to EA patients.

The role of chemoattractant receptors in shaping the tumor microenvironment

Chemoattractant receptors are a family of seven transmembrane G protein coupled receptors (GPCRs) initially found to mediate the chemotaxis and activation of immune cells. During the past decades, the functions of these GPCRs have been discovered to not only regulate leukocyte trafficking and promote immune responses, but also play important roles in homeostasis, development, angiogenesis, and tumor progression. Accumulating evidence indicates that chemoattractant GPCRs and their ligands promote the progression of malignant tumors based on their capacity to orchestrate the infiltration of the tumor microenvironment by immune cells, endothelial cells, fibroblasts, and mesenchymal cells. This facilitates the interaction of tumor cells with host cells, tumor cells with tumor cells, and host cells with host cells to provide a basis for the expansion of established tumors and development of distant metastasis. In addition, many malignant tumors of the nonhematopoietic origin express multiple chemoattractant GPCRs that increase the invasiveness and metastasis of tumor cells. Therefore, GPCRs and their ligands constitute targets for the development of novel antitumor therapeutics.

Fluorescent-tilmanocept for tumor margin analysis in the mouse model

BACKGROUND

Dendritic cells (DC) are localized in close proximity to cancer cells in many well-known tumors, and thus maybe a useful target for tumor margin assessment.

MATERIALS AND METHODS

[(99m)Tc]- cyanine 7 (Cy7)-tilmanocept was synthesized and in vitro binding assays to bone marrow-derived DC were performed. Fifteen mice, implanted with either 4T1 mouse mammary or K1735 mouse melanoma tumors, were administered 1.0 nmol of [(99m)Tc]-Cy7-tilmanocept via tail vein injection. After fluorescence imaging 1 or 2 h after injection, the tumor, muscle, and blood were assayed for radioactivity to calculate percent-injected dose. Digital images of the tumors after immunohistochemical staining for DC were analyzed to determine DC density.

RESULTS

In vitro binding demonstrated subnanomolar affinity of [(99m)Tc]-Cy7-tilmanocept to DC (KA = 0.31 ± 0.11 nM). After administration of [(99m)Tc]-Cy7-tilmanocept, fluorescence imaging showed a 5.5-fold increase in tumor signal as compared with preinjection images and a 3.3-fold difference in fluorescence activity when comparing the tumor with the surgical bed after tumor excision. Immunohistochemical staining analysis demonstrated that DC density positively correlated with tumor percent of injected dose per gram (r = 0.672, P = 0.03), and higher DC density was observed at the periphery versus center of the tumor (186 ± 54 K versus 64 ± 16 K arbitrary units, P = 0.001).

CONCLUSIONS

[(99m)Tc]-Cy7-tilmanocept exhibits in vitro and in vivo tumor-specific binding to DC and maybe useful as a tumor margin targeting agent.

Alterations of costimulatory molecules and instructive cytokines expressed by dendritic cells in the microenvironment of an endogenous mouse lymphoma

Costimulatory surface molecules and instructive cytokines expressed by dendritic cells (DCs) determine the outcome of an immune response. In malignant disease, DCs are often functionally compromised. In most tumors studied so far, the deficient induction of effective T cell responses has been associated with a blockade of DC maturation, but little has been known on DCs infiltrating malignant B cell lymphoma. Here, we investigated for the first time the phenotypic and functional status of DCs in B cell lymphoma, and we analyzed the network of DCs, tumor cells, natural killer (NK) cells and cytokines present in the tumor micromilieu. Therefor, we used an endogenous myc-transgenic mouse lymphoma model, because transplanted tumor cells foster an IFN-γ-driven Th1 antitumor response rather than an immunosuppressive environment, which is observed in autochthonous neoplasias. Lymphoma-infiltrating DCs showed a mature phenotype and a Th2-inducing cytokine pattern. This situation is in contrast to most human malignancies and mouse models described. Cellular contacts between DCs and tumor cells, which involved CD62L on the lymphoma, caused upregulation of costimulatory molecules, whereas IL-10 primarily derived from lymphoma cells induced an IL-12/IL-10 shift in DCs. Thus, alteration of costimulatory molecules and instructive cytokines was mediated by distinct mechanisms. Normal NK cells were able to additionally modulate DC maturation but this effect was absent in the lymphoma environment where IFN-γ production by NK cells was severely impaired. These data are relevant for establishing novel immunotherapeutic approaches against B cell lymphoma.

Tumor secretion of CCL22 activates intratumoral Treg infiltration and is independent prognostic predictor of breast cancer

It has been reported that dense intratumoral infiltration of Foxp3 ⁺Tregs (Tregs) was an independent factor for poor prognosis of breast cancer (BC) patients. However, the cytokines activating the Treg infiltration are not known. This study was undertaken to evaluate the role of CCL22 and TGF-β1 in this cascade and their prognostic significance for BC patients. 417 cases of invasive breast cancer were selected from the prior study cohort and the expressions of CCL22 and TGF-β1 were assessed by immunohistochemistry. It was identified that tumor secretion of CCL22 was positively correlated with the intratumoral Treg infiltration (P<0.0001), but its association with lymphoid aggregates surrounding the tumor was not proven to be significant (P=0.056). Moreover, CCL22 expression was found to be associated with the tumor histological features known to be related with unfavorable prognosis of patients, including high histological grade (P<0.0001), negative ER (P<0.0001), negative PR (P=0.001), and HER2 amplification (P=0.028). Similar to intratumoral Treg infiltrates, CCL22 tumor secretion correlated with the prognosis of the molecular subtypes of breast carcinoma (P<0.0001). Univariate analysis revealed CCL22 to be an independent prognostic factor for overall survival (OS, P<0.0001) and progression-free survival (PFS, P<0.0001) of BC patients that were confirmed by multivariate analysis (P=0.011 and P=0.010 respectively). In contrast, although TGF-β1 expression was positively correlated with both Tregs infiltrates into the tumor bed and lymphoid aggregates surrounding the tumor (P=0.023; P=0.046, respectively), its expression was not significantly associated with the molecular subtypes of breast carcinoma and the prognosis of the patients. Our study indicates that both CCL22 and TGF-β1 are candidate chemoattractants for intratumoral Foxp3 ⁺Tregs infiltration; however, unlike the later, CCL22 is an independent prognostic predictor of BC patients, and it therefore may have the potential to serve as a target for immunotherapeutic strategy of BC.

Human dendritic cells subsets as targets and vectors for therapy

The skin immune system includes a complex network of dendritic cells (DCs). In addition to generating cellular and humoral immunity against pathogens, skin DCs are involved in tolerogenic mechanisms that maintain immune homeostasis and in pathogenic chronic inflammation in which immune responses are unrestrained. Harnessing DC function by directly targeting DC-derived molecules or by selectively modulating DC subsets is a novel strategy for ameliorating inflammatory diseases. In this short review, we discuss recent advances in understanding the functional specialization of skin DCs and the potential implication for future DC-based therapeutic strategies.

Breast cancer-derived transforming growth factor-β and tumor necrosis factor-α compromise interferon-α production by tumor-associated plasmacytoid dendritic cells

We previously reported that plasmacytoid dendritic cells (pDCs) infiltrating breast tumors are impaired for their interferon-α (IFN-α) production, resulting in local regulatory T cells amplification. We designed our study to decipher molecular mechanisms of such functional defect of tumor-associated pDC (TApDC) in breast cancer. We demonstrate that besides IFN-α, the production by Toll-like receptor (TLR)-activated healthy pDC of IFN-β and TNF-α but not IP-10/CXCL10 nor MIP1-α/CCL3 is impaired by the breast tumor environment. Importantly, we identified TGF-β and TNF-α as major soluble factors involved in TApDC functional alteration. Indeed, recombinant TGF-β1 and TNF-α synergistically blocked IFN-α production of TLR-activated pDC, and neutralization of TGF-β and TNF-α in tumor-derived supernatants restored pDCs' IFN-α production. The involvment of tumor-derived TGF-β was further confirmed in situ by the detection of phosphorylated Smad2 in the nuclei of TApDC in breast tumor tissues. Mechanisms of type I IFN inhibition did not involve TLR downregulation but the inhibition of IRF-7 expression and nuclear translocation in pDC after their exposure to tumor-derived supernatants or recombinant TGF-β1 and TNF-α. Our findings indicate that targeting TApDC to restore their IFN-α production might be an achievable strategy to induce antitumor immunity in breast cancer by combining TLR7/9-based immunotherapy with TGF-β and TNF-α antagonists.

Genetically determined inflammatory-response related cytokine and chemokine transcript profiles between mammary carcinoma resistant and susceptible rat strains

Multiple human breast and rat mammary carcinoma susceptibility (Mcs) alleles have been identified. Wistar Kyoto (WKY) rats are resistant to developing mammary carcinomas, while Wistar Furth (WF) females are susceptible. Gene transcripts at Mcs5a1, Mcs5a2, and Mcs5c are differentially expressed between resistant WKY and susceptible WF alleles in immune-system tissues. We hypothesized that immune-related gene transcript profiles are genetically determined in mammary carcinoma resistant and susceptible mammary glands. Low-density QPCR arrays were used to compare inflammation related genes between mammary carcinoma resistant WKY and susceptible WF females. Mammary gland gene transcript levels predicted to be different based on arrays were tested in independent samples. In total, 20 females per strain were exposed to 7,12-dimethylbenz(a)anthracene (DMBA) to induce mammary carcinogenesis. Twelve age-matched controls per strain without DMBA were included to determine main effects of DMBA-exposure. Significant (ANOVA P ≤ 0.01) effects of strain on mammary gland transcript level were observed for Cx3cl1, Il11ra, Il4, C3, Ccl20, Ccl11, Itgb2, Cxcl12, and Cxcr7. Significant effects of DMBA-exposure were observed for Cx3cl1, Il11ra, Cxcr4, Il4ra, and Il4. Strain and DMBA-exposure interaction effects were significant for Cx3cl1. Transcript levels of Cxcr7 relative to Cxcr4 were modified differently by DMBA in mammary carcinoma resistant and susceptible strains. In conclusion, several genetically-determined differences in cytokine, chemokine, and receptor gene transcript levels were identified between mammary carcinoma susceptible and resistant mammary glands, which may be indicative of cell populations and activities that suppress mammary carcinogenesis in resistant genotypes.

The differential production of cytokines by human Langerhans cells and dermal CD14(+) DCs controls CTL priming

We recently reported that human epidermal Langerhans cells (LCs) are more efficient than dermal CD14(+) DCs at priming naive CD8(+) T cells into potent CTLs. We hypothesized that distinctive dendritic cell (DC) cytokine expression profiles (ie, IL-15 produced by LCs and IL-10 expressed by dermal CD14(+) DCs) might explain the observed functional difference. Blocking IL-15 during CD8(+) T-cell priming reduced T-cell proliferation by ∼ 50%. These IL-15-deprived CD8(+) T cells did not acquire the phenotype of effector memory cells. They secreted less IL-2 and IFN-γ and expressed only low amounts of CD107a, granzymes and perforin, and reduced levels of the antiapoptotic protein Bcl-2. Confocal microscopy analysis showed that IL-15 is localized at the immunologic synapse of LCs and naive CD8(+) T cells. Conversely, blocking IL-10 during cocultures of dermal CD14(+) DCs and naive CD8(+) T cells enhanced the generation of effector CTLs, whereas addition of IL-10 to cultures of LCs and naive CD8(+) T cells inhibited their induction. TGF-β1 that is transcribed by dermal CD14(+) DCs further enhanced the inhibitory effect of IL-10. Thus, the respective production of IL-15 and IL-10 explains the contrasting effects of LCs and dermal CD14(+) DCs on CD8(+) T-cell priming.

Early detection of tumor cells by innate immune cells leads to T(reg) recruitment through CCL22 production by tumor cells

In breast carcinomas, patient survival seems to be negatively affected by the recruitment of regulatory T cells (T(reg)) within lymphoid aggregates by CCL22. However, the mechanisms underpinning this process, which may be of broader significance in solid tumors, have yet to be described. In this study, we determined how CCL22 production is controlled in tumor cells. In human breast carcinoma cell lines, CCL22 was secreted at low basal levels that were strongly increased in response to inflammatory signals [TNF-α, IFN-γ, and interleukin (IL)-1β], contrasting with CCL17. Primary breast tumors and CD45(+) infiltrating immune cells appeared to cooperate in driving CCL22 secretion, as shown clearly in cocultures of breast tumor cell lines and peripheral blood mononuclear cells (PBMC) or their supernatants. We determined that monocyte-derived IL-1β and TNF-α are key players as monocyte depletion or neutralization of these cytokines attenuated secretion of CCL22. However, when purified monocytes were used, exogenous human IFN-γ was also required to generate this response suggesting a role for IFN-γ-producing cells within PBMCs. In this setting, we found that human IFN-γ could be replaced by the addition of (i) IL-2 or K562-activated natural killer (NK) cells or (ii) resting NK cells in the presence of anti-MHC class I antibody. Taken together, our results show a dialogue between NK and tumor cells leading to IFN-γ secretion, which in turn associates with monocyte-derived IL-1β and TNF-α to drive production of CCL22 by tumor cells and subsequent recruitment of T(reg). As one validation of this conclusion in primary breast tumors, we showed that NK cells and macrophages tend to colocalize within tumors. In summary, our findings suggest that at early times during tumorigenesis, the detection of tumor cells by innate effectors (monocytes and NK cells) imposes a selection for CCL22 secretion that recruits T(reg) to evade this early antitumor immune response.

Prognostic value of the expression of C-Chemokine Receptor 6 and 7 and their ligands in non-metastatic breast cancer

Background

Chemokines and chemokine receptors are major actors of leukocytes trafficking and some have been shown to play an important role in cancer metastasis. Chemokines CCL19, CCL20 and CCL21 and their receptors CCR6 and CCR7, were assessed as potential biomarkers of metastatic dissemination in primary breast cancer.

Methods

Biomarker expression levels were evaluated using immunohistochemistry on paraffin-embedded tissue sections of breast cancer (n = 207).

Results

CCR6 was expressed by tumor cells in 35% of cases. CCR7 was expressed by spindle shaped stromal cells in 43% of cases but not by tumor cells in this series. CCL19 was the only chemokine found expressed in a significant number of breast cancers and was expressed by both tumor cells and dendritic cells (DC). CCR6, CCL19 and CCR7 expression correlated with histologic features of aggressive disease. CCR6 expression was associated with shorter relapse-free survival (RFS) in univariate and but not in multivariate analysis (p = 0.0316 and 0.055 respectively), and was not associated with shorter overall survival (OS). Expression of CCR7 was not significantly associated with shorter RFS or OS. The presence of CCL19-expressing DC was associated with shorter RFS in univariate and multivariate analysis (p = 0.042 and 0.020 respectively) but not with shorter OS.

Conclusion

These results suggest a contribution of CCR6 expression on tumor cells and CCL19-expressing DC in breast cancer dissemination. In our series, unlike what was previously published, CCR7 was exclusively expressed on stromal cells and was not associated with survival.

Epithelial cell secretions from the human female reproductive tract inhibit sexually transmitted pathogens and Candida albicans but not Lactobacillus

Female reproductive tract (FRT) epithelial cells protect against potential pathogens and sexually transmitted infections. The purpose of this study was to determine if epithelial cells from the upper FRT secrete antimicrobials that inhibit reproductive tract pathogens that threaten women's health. Apical secretions from primary cultures of Fallopian tube, uterine, cervical, and ectocervical epithelial cells were incubated with Neisseria gonorrhoeae, Candida albicans (yeast and hyphal forms), human immunodeficiency virus 1 (HIV-1), and Lactobacillus crispatus before being tested for their ability to grow and/or infect target cells. Epithelial cell secretions from the upper FRT inhibit N. gonorrhoeae and both forms of Candida, as well as reduce HIV-1 (R5) infection of target cells. In contrast, none had an inhibitory effect on L. crispatus. An analysis of cytokines and chemokines in uterine secretions revealed several molecules that could account for pathogen inhibition. These findings provide definitive evidence for the critical role of epithelial cells in protecting the FRT from infections, without comprising the beneficial presence of L. crispatus, which is part of the normal vaginal microflora of humans.

Chemokine-mediated distribution of dendritic cell subsets in renal cell carcinoma

Background

Renal cell carcinoma (RCC) represents one of the most immunoresponsive cancers. Antigen-specific vaccination with dendritic cells (DCs) in patients with metastatic RCC has been shown to induce cytotoxic T-cell responses associated with objective clinical responses. Thus, clinical trials utilizing DCs for immunotherapy of advanced RCCs appear to be promising; however, detailed analyses concerning the distribution and function of DC subsets in RCCs are lacking.

Methods

We characterized the distribution of the different immature and mature myeloid DC subsets in RCC tumour tissue and the corresponding normal kidney tissues. In further analyses, the expression of various chemokines and chemokine receptors controlling the migration of DC subsets was investigated.

Results

The highest numbers of immature CD1a+ DCs were found within RCC tumour tissue. In contrast, the accumulation of mature CD83+/DC-LAMP+ DCs were restricted to the invasive margin of the RCCs. The mature DCs formed clusters with proliferating T-cells. Furthermore, a close association was observed between MIP-3α-producing tumour cells and immature CCR6+ DC recruitment to the tumour bed. Conversely, MIP-3β and SLC expression was only detected at the tumour border, where CCR7-expressing T-cells and mature DCs formed clusters.

Conclusion

Increased numbers of immature DCs were observed within the tumour tissue of RCCs, whereas mature DCs were found in increased numbers at the tumour margin. Our results strongly implicate that the distribution of DC subsets is controlled by local lymphoid chemokine expression. Thus, increased expression of MIP-3α favours recruitment of immature DCs to the tumour bed, whereas de novo local expression of SLC and MIP-3β induces accumulation of mature DCs at the tumour margin forming clusters with proliferating T-cells reflecting a local anti-tumour immune response.

Differences in tumor regulatory T-cell localization and activation status impact patient outcome

The presence of regulatory T cells (Treg) has been described in a large panel of solid tumors. However, their impact on tumor progression differs according to the tumor type analyzed. We recently obtained evidence in breast carcinoma that Treg localized within lymphoid aggregates, but not in the tumor bed, have a negative impact on patients' survival. Moreover, we showed selective Treg recruitment through CCR4/CCL22 in the lymphoid aggregates upon contact with dendritic cells (DC), where they became strongly and selectively activated (ICOS(high)) and block conventional T-cell response. Here, we discuss the meaning and potential implication of these novel findings.

Lymphopenia as a prognostic factor for overall survival in advanced carcinomas, sarcomas, and lymphomas

Lymphopenia is frequent in advanced cancers and predicts the toxicity of chemotherapy. Its effect on relapse and survival is uncertain. Its prognostic value for survival was analyzed in three databases of previously reported prospective multicenter studies: (a) FEC chemotherapy in metastatic breast carcinoma; (b) CYVADIC in advanced soft tissue sarcoma (European Organization for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group 62791); and (c) prospective, consecutive phase III studies of aggressive diffuse large-cell non-Hodgkin's lymphomas conducted at Centre Léon Bérard between 1987 and 1993. Univariate and multivariate analyses of prognostic factors for survival were performed. The incidence of lymphopenia of <1,000/microL before treatment was constant among the series: 25%, 24%, and 27%, respectively. Lymphopenia was significantly more frequent (P < 0.05) in metastatic breast cancer patients with performance status (PS) of >1, non-Hodgkin's lymphoma patients with international prognostic index (IPI) of > 0, and advanced soft tissue sarcoma and metastatic breast cancer patients with bone metastases. Inunivariate analysis, lymphopenia of <1,000/microL significantly correlated to overall survival in patients with metastatic breast cancer (median, 10 versus 14 mo; P < 0.0001), advanced soft tissue sarcoma (median, 5 versus 10 months; P < 0.01), and non-Hodgkin lymphoma (median, 11 versus 94 months; P < 0.0001). In multivariate analysis (Cox model), lymphopenia was an independent prognostic factor for overall survival in metastatic breast cancer [RR (relative risk), 1.8; 95% CI (confidence interval), 1.3-2.4] along with liver metastases and PS; in advanced soft tissue sarcoma (RR, 1.46; 95% CI, 1.0-2.1) along with liver metastases, lung metastases, and PS; and in non-Hodgkin's lymphoma (RR, 1.48; 95% CI, 1.03-2.1) along with IPI. Our findings show that lymphopenia is an independent prognostic factor for overall and progression-free survival in several cancers.

Tumor-infiltrating regulatory dendritic cells inhibit CD8+ T cell function via L-arginine metabolism

Dendritic cells (DC) have a critical effect on the outcome of adaptive immune responses against growing tumors. Whereas it is generally assumed that the presence of phenotypically mature DCs should promote protective antitumor immunity, evidence to the contrary does exist. We describe here a novel mechanism by which tumor-infiltrating dendritic cells (TIDC) actively contribute to the suppression of protective CD8(+) T-cell-based antitumor immunity. Using the BALB/NeuT model of spontaneously arising mammary carcinoma, we found that canonical MHC II(+)/CD11b(+)/CD11c(high) TIDCs act as regulatory DCs to suppress CD8(+) T-cell function, resulting in diminished T-cell-based antitumor immunity in vivo. Stimulation of naive T cells with regulatory TIDCs resulted in an altered cell fate program characterized by minimal T-cell expansion, impaired IFNgamma production, and anergy. Suppression by regulatory TIDCs overcame stimulatory signals provided by standard DCs, occurred in the absence of cognate interactions with T cells, and was mediated primarily by arginase metabolism of l-arginine. Immunosuppressive TIDCs were found in every murine tumor type examined and were phenotypically distinct from tumor-infiltrating CD11c(int-low)/CD11b(+)/Gr-1(+) myeloid-derived suppressor cells. Thus, within the tumor microenvironment, MHC II(+) TIDCs can function as potent suppressors of CD8(+) T-cell immunity.

Regulatory T cells recruited through CCL22/CCR4 are selectively activated in lymphoid infiltrates surrounding primary breast tumors and lead to an adverse clinical outcome

Immunohistochemical analysis of FOXP3 in primary breast tumors showed that a high number of tumor-infiltrating regulatory T cells (Ti-Treg) within lymphoid infiltrates surrounding the tumor was predictive of relapse and death, in contrast to those present within the tumor bed. Ex vivo analysis showed that these tumor-infiltrating FOXP3(+) T cells are typical Treg based on their CD4(+)CD25(high)CD127(low)FOXP3(+) phenotype, their anergic state on in vitro stimulation, and their suppressive functions. These Ti-Treg could be selectively recruited through CCR4 as illustrated by (a) selective blood Treg CCR4 expression and migration to CCR4 ligands, (b) CCR4 down-regulation on Ti-Treg, and (c) correlation between Ti-Treg in lymphoid infiltrates and intratumoral CCL22 expression. Importantly, in contrast to other T cells, Ti-Treg are selectively activated locally and proliferate in situ, showing T-cell receptor engagement and suggesting specific recognition of tumor-associated antigens (TAA). Immunohistochemical stainings for ICOS, Ki67, and DC-LAMP show that Ti-Treg were close to mature DC-LAMP(+) dendritic cells (DC) in lymphoid infiltrates but not in tumor bed and were activated and proliferating. Furthermore, proximity between Ti-Treg, CD3(+), and CD8(+) T cells was documented within lymphoid infiltrates. Altogether, these results show that Treg are selectively recruited within lymphoid infiltrates and activated by mature DC likely through TAA presentation, resulting in the prevention of effector T-cell activation, immune escape, and ultimately tumor progression. This study sheds new light on Treg physiology and validates CCR4/CCL22 and ICOS as therapeutic targets in breast tumors, which represent a major health problem.

Mucin-induced apoptosis of monocyte-derived dendritic cells during maturation

Many tumors arising from epithelial tissues produce mucins, which readily come into contact with infiltrating cells in cancer tissues. MUC2 mucins were purified from the conditioned medium of a colorectal cancer cell line, LS180 cells. It is known that in cancer patients, the number of dendritic cells (DCs) is reduced and their function is impaired. Mature DCs were generated from human peripheral blood monocytes through successive treatments with GM-CSF and IL-4, and then with proinflammatory mediators. When monocytes were cultured in the presence of MUC2 mucins in addition to GM-CSF and IL-4 at an early stage of development, mature DCs expressing CD83 decreased and apoptotic cells increased in a dose-dependent manner. During the development of DCs, sialic acid-binding Ig-like lectin (Siglec)-3 was constantly expressed. We prepared recombinant soluble Siglec-3 corresponding to the ectodomain of Siglec-3 and confirmed the binding of soluble Siglec-3 to the MUC2 mucins, probably through alpha2,6-sialic acid-containing O-glycans including a sialyl Tn antigen, which is known to bind to Siglec-3. Apoptosis was partially inhibited by anti-Siglec-3 mAb or recombinant soluble Siglec-3. These results suggest that apoptosis was partially induced through the ligation of the MUC2 mucins with Siglec-3.

Smooth muscle cells, dendritic cells and mast cells are sources of TNFalpha and nitric oxide in human carotid artery atherosclerosis

INTRODUCTION

In atherogenesis, dendritic cells, beside presenting antigens, may be sources of tumour necrosis factor (TNF)alpha and nitric oxide (NO), together with mast cells and smooth muscle cells.

MATERIAL AND METHODS

We have looked at the expression of TNFalpha and inducible NO synthase (iNOs) by these cells by affinity cytochemistry in autoptical specimens from normal carotid arteries and not ruptured, hemorrhagic or calcified atheromata.

RESULTS

Round to dendritic, major histocompatibility complex class II molecules (MHC-II+) cells and avidin-labeled mast cells were rare in normal arteries and significantly more numerous in atheromata. Many MHC-II+ cells expressed S-100 antigen; while a few were positive for phalloidin; appreciable fractions of these cells were immunoreactive for TNFalpha and iNOs, both in control specimens and atheromata. The fraction of mast cells labeled for iNOs was significantly lower in atheromata than in controls. Phalloidin positive cells were the most abundant cell type in the normal intima and atheromata; the fractions of these cells labeled for TNFalpha and iNOs were significantly higher in atheromata than in controls. Very few of these cells were also labeled for MHC-II. Computerized image analysis confirmed that the amounts of iNOs and TNFalpha were higher in atheromata than in controls. The increase in TNFalpha in atheromata was also confirmed by western blot.

CONCLUSIONS

Dendritic cells and mast cells can participate to the generation of TNFalpha and NO in the normal arterial wall and in atheromata, but myointimal cells are candidates as major sources of these molecules.

Inflammatory cell infiltration of tumors: Jekyll or Hyde

Inflammatory cell infiltration of tumors contributes either positively or negatively to tumor invasion, growth, metastasis, and patient outcomes, creating a Dr. Jekyll or Mr. Hyde conundrum when examining mechanisms of action. This is due to tumor heterogeneity and the diversity of the inflammatory cell phenotypes that infiltrate primary and metastatic lesions. Tumor infiltration by macrophages is generally associated with neoangiogenesis and negative outcomes, whereas dendritic cell (DC) infiltration is typically associated with a positive clinical outcome in association with their ability to present tumor antigens (Ags) and induce Ag-specific T cell responses. Myeloid-derived suppressor cells (MDSCs) also infiltrate tumors, inhibiting immune responses and facilitating tumor growth and metastasis. In contrast, T cell infiltration of tumors provides a positive prognostic surrogate, although subset analyses suggest that not all infiltrating T cells predict a positive outcome. In general, infiltration by CD8(+) T cells predicts a positive outcome, while CD4(+) cells predict a negative outcome. Therefore, the analysis of cellular phenotypes and potentially spatial distribution of infiltrating cells are critical for an accurate assessment of outcome. Similarly, cellular infiltration of metastatic foci is also a critical parameter for inducing therapeutic responses, as well as establishing tumor dormancy. Current strategies for cellular, gene, and molecular therapies are focused on the manipulation of infiltrating cellular populations. Within this review, we discuss the role of tumor infiltrating, myeloid-monocytic cells, and T lymphocytes, as well as their potential for tumor control, immunosuppression, and facilitation of metastasis.

The multifaceted roles of chemokines in malignancy

Tumor development and progression are multifactorial processes, regulated by a large variety of intrinsic and microenvironmental factors. A key role in cancer is played by members of the chemokine superfamily. Chemokines and their receptors are expressed by tumor cells and by host cells, in primary tumors and in specific metastatic loci. The effects of chemokines on tumorigenesis are diverse: While some members of the superfamily significantly support this process, others inhibit fundamental events required for tumor establishment and metastasis. The current review describes the multifaceted roles of chemokines in malignancy, addressing four major aspects of their activities: (1) inducing leukocyte infiltration to tumors and regulating immune functions, with emphasis on tumor-associated macrophages (and the chemokines CCL2, CCL5), T cells (and the chemokines CXCL9, CXCL10) and dendritic cells (and the chemokines CCL19, CCL20, CCL21); (2) directing the homing of tumor cells to specific metastatic sites (the CXCL12-CXCR4 axis); (3) regulating angiogenic processes (mainly the ELR(+)-CXC and non-ELR-CXC chemokines); (4) acting directly on the tumor cells to control their malignancy-related functions. Together, these different chemokine functions establish a net of interactions between the tumor cells and their microenvironment, and partly dictate the fate of the malignancy cascade.

Intratumoral cytokines/chemokines/growth factors and tumor infiltrating dendritic cells: friends or enemies?

The tumor microenvironment consists of a variable combination of tumor cells, stromal fibroblasts, endothelial cells and infiltrating leukocytes, such as macrophages, T lymphocytes, and dendritic cells. A variety of cytokines, chemokines and growth factors are produced in the local tumor environment by different cells accounting for a complex cell interaction and regulation of differentiation, activation, function and survival of multiple cell types. The interaction between cytokines, chemokines, growth factors and their receptors forms a comprehensive network at the tumor site, which is primary responsible for overall tumor progression and spreading or induction of antitumor immune responses and tumor rejection. Although the general thought is that dendritic cells are among the first cells migrating to the tumor site and recognizing tumor cells for the induction of specific antitumor immunity, the clinical relevance of dendritic cells at the site of the tumor remains a matter of debate regarding their role in the generation of successful antitumor immune responses in human cancers. While several lines of evidence suggest that intratumoral dendritic cells play an important role in antitumor immune responses, understanding the mechanisms of dendritic cell/tumor cell interaction and modulation of activity and function of different dendritic cell subtypes at the tumor site is incomplete. This review is limited to discussing the role of intratumoral cytokine network in the understanding immunobiology of tumor-associated dendritic cells, which seems to possess different regulatory functions at the tumor site.

Molecular basis of pregnancy-induced breast cancer protection

We have postulated that the lifetime protective effect of an early pregnancy against breast cancer is due to the complete differentiation of the mammary gland characterized by a specific genomic signature imprinted by the physiological process of pregnancy. In the present work, we show evidence that the breast tissue of postmenopausal parous women has had a shifting of stem cell 1 to stem cell 2 with a genomic signature different from similar structures derived from postmenopausal nulliparous women that have stem cell 1. Those genes that are significantly different are grouped in major categories on the basis of their putative functional significance. Among them are those gene transcripts related to immune surveillance, DNA repair, transcription, chromatin structure/activators/co-activators, growth factor and signal transduction pathway, transport and cell trafficking, cell proliferation, differentiation, cell adhesion, protein synthesis and cell metabolism. From these data, it was concluded that during pregnancy there are significant genomic changes that reflect profound alterations in the basic physiology of the mammary gland that explain the protective effect against carcinogenesis. The implication of this knowledge is that when the genomic signature of protection or refractoriness to carcinogenesis is acquired by the shifting of stem cell 1 to stem cell 2, the hormonal milieu induced by pregnancy or pregnancy-like conditions is no longer required. This is a novel concept that challenges the current knowledge that a chemopreventive agent needs to be given for a long period to suppress a metabolic pathway or abrogate the function of an organ.

The genomic signature of breast cancer prevention

Early pregnancy imprints in the breast permanent genomic changes or a signature that reduces the susceptibility of this organ to cancer. The breast attains its maximum development during pregnancy and lactation. After menopause, the breast regresses in both nulliparous and parous women containing lobular structures designated Lob.1. The Lob 1 found in the breast of nulliparous women and of parous women with breast cancer never went through the process of differentiation, retaining a high concentration of epithelial cells that are targets for carcinogens and therefore susceptible to undergoing neoplastic transformation, these cell are called Stem cells 1, whereas Lob 1 structures found in the breast of early parous postmenopausal women free of mammary pathology, on the other hand, are composed of an epithelial cell population that is refractory to transformation called Stem cells 2. The degree of differentiation acquired through early pregnancy has changed the genomic signature that differentiates the Lob 1 from the early parous women from that of the nulliparous women by shifting the Stem cell 1 to a Stem cell 2, making this the postulated mechanism of protection conferred by early full-term pregnancy. The identification of a putative breast stem cell (Stem cell 1) has reached in the last decade a significant impulse and several markers also reported for other tissues have been found in the mammary epithelial cells of both rodents and humans. The data obtained thus far is supporting the concept that the lifetime protective effect of an early pregnancy against breast cancer is due to the complete differentiation of the mammary gland, which results in the replacement of the Stem cell 1 that is a component of the nulliparous breast epithelium with a new stem cell, called Stem cell 2, which is characterized by a specific genomic signature. The pattern of gene expression of the stem cell 2 could potentially be used as useful intermediate end points for evaluating the degree of mammary gland differentiation and for evaluating preventive agents such as human chorionic gonadotropin.

Dendritic cells recognize tumor-specific glycosylation of carcinoembryonic antigen on colorectal cancer cells through dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin

Dendritic cells play a pivotal role in the induction of antitumor immune responses. Immature dendritic cells are located intratumorally within colorectal cancer and intimately interact with tumor cells, whereas mature dendritic cells are present peripheral to the tumor. The majority of colorectal cancers overexpress carcinoembryonic antigen (CEA), and malignant transformation changes the glycosylation of CEA on colon epithelial cells, resulting in higher levels of Lewis(x) and de novo expression of Lewis(y) on tumor-associated CEA. Dendritic cells express the C-type lectin dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) that has high affinity for nonsialylated Lewis antigens, so we hypothesized that DC-SIGN is involved in recognition of colorectal cancer cells by dendritic cells. We show that immature dendritic cells within colorectal cancer express DC-SIGN and that immature dendritic cells but not mature dendritic cells interact with tumor cells. DC-SIGN mediates these interactions through binding of Lewis(x) and Lewis(y) carbohydrates on CEA of colorectal cancer cells. In contrast, DC-SIGN does not bind CEA expressed on normal colon epithelium that contains low levels of Lewis antigens. This indicates that dendritic cells may recognize colorectal cancer cells through binding of DC-SIGN to tumor-specific glycosylation on CEA. Similar to pathogens that target DC-SIGN to escape immunosurveillance, tumor cells may interact with DC-SIGN to suppress dendritic cell functions.

Fusion of dendritic cells with multiple myeloma cells results in maturation and enhanced antigen presentation

Dendritic cells (DCs) are potent antigen-presenting cells that are uniquely capable of inducing primary immune responses. Although tumour cells may directly inhibit DC maturation, exposure to tumour products may also result in their activation. Fusions of cancer cells and DCs are being explored as cancer vaccines. The effect of tumour cell fusion on DC maturation and their functional characteristics has not been defined. In the present study, immature and mature DC generated from human CD34+ and peripheral blood precursors were fused to multiple myeloma cells in the presence of polyethylene glycol. Fusion of both immature and mature DCs with tumour cells resulted in an activated phenotype. In this regard, fusion cells expressed interleukin-12, a cytokine essential for the induction of T-helper cell type 1 immunity. In contrast to immature DCs, fusion cells also strongly expressed CC-chemokine receptor R7, which is responsible for DC migration to draining lymph nodes. Fusions generated with both immature and mature DCs also potently stimulated T-cell expression of gamma-interferon and cytotoxic T lymphocyte killing of tumour targets. These findings demonstrate that tumour cell fusion induces DC maturation and the development of an activated phenotype necessary for their effectiveness as cancer vaccines.

Recombinant Tumor-Associated MUC1 Glycoprotein Impairs the Differentiation and Function of Dendritic Cells

Tumors exploit several strategies to evade immune recognition, including the production of a large number of immunosuppressive factors, which leads to reduced numbers and impaired functions of dendritic cells (DCs) in the vicinity of tumors. We have investigated whether a mucin released by tumor cells could be involved in causing these immunomodulating effects on DCs. We used a recombinant purified form of the MUC1 glycoprotein, an epithelial associated mucin that is overexpressed, aberrantly glycosylated, and shed during cancer transformation. The O-glycosylation profile of the recombinant MUC1 glycoprotein (ST-MUC1) resembled that expressed by epithelial tumors in vivo, consisting of large numbers of sialylated core 1 (sialyl-T, ST) oligosaccharides. When cultured in the presence of ST-MUC1, human monocyte-derived DCs displayed a modified phenotype with decreased expression of costimulatory molecules (CD86, CD40), Ag-presenting molecules (DR and CD1d), and differentiation markers (CD83). In contrast, markers associated with an immature phenotype, CD1a and CD206 (mannose receptor), were increased. This effect was already evident at day 4 of DC culture and was dose dependent. The modified phenotype of DCs corresponded to an altered balance in IL-12/IL-10 cytokine production, with DC expressing an IL-10(high)IL-12(low) phenotype after exposure to ST-MUC1. These DCs were defective in their ability to induce immune responses in both allogeneic and autologous settings, as detected in proliferation and ELISPOT assays. The altered DC differentiation and Ag presentation function induced by the soluble sialylated tumor-associated mucin may represent a mechanism by which epithelial tumors can escape immunosurveillance.

CD1a expression by Barrett's metaplasia of gastric type may help to predict its evolution towards cancer

As emerging in the recent literature, CD1a has been regarded as a molecule whose expression may reflect tumour evolution. The aim of the present work was to investigate the expression of CD1a in a series of Barrett's metaplasia (BM), gastric type (GTBM), with and without follow-up, in order to analyse whether its expression may help to diagnose this disease and to address the outcome. Indeed, GTBM may be confused sometimes with islets of ectopic gastric mucosa and its evolution towards dysplasia (Dy) or carcinoma (Ca) could not be foreseen. We showed a significant higher expression of CD1a in GTBM than in both Dy and Ca; nevertheless, the number of positive GTBM was significantly lower in the group of cases that at follow-up underwent Dy or Ca. Our data address that CD1a may be a novel biomarker for BM and that its expression may help to predict the prognosis of this pathology.