Treating BCG-Induced Cystitis with Combined Chondroitin and Hyaluronic Acid Instillations in Bladder Cancer

In non-muscle invasive bladder cancer, Bacillus Calmette-Guérin (BCG) responders benefit from strong Th1-type inflammatory and T cell responses mediating tumor rejection. However, the corresponding lack of anti-inflammatory Th2-type immunity impairs tissue repair in the bladder wall and facilitates the development of cystitis, causing urinary pain, urgency, incontinence, and frequency. Mechanistically, the leakage of the glycosaminoglycan (GAG) layer enables an influx of potassium ions, bacteria, and urine solutes towards the underlying bladder tissue, promoting chronic inflammation. Treatments directed towards re-establishing this mucopolysaccharide-based protective barrier are urgently needed. We discuss the pathomechanisms, as well as the therapeutic rationale of how chondroitin and hyaluronic acid instillations can reduce or prevent BCG-induced irritative bladder symptoms. Moreover, we present a case series of five patients with refractory BCG-induced cystitis successfully treated with combined chondroitin and hyaluronic acid instillations.

Crosstalk between purinergic receptor P2Y11 and chemokine receptor CXCR7 is regulated by CXCR4 in human macrophages

P2Y11 is a G protein-coupled ATP receptor that activates IL-1 receptor (IL-1R) in a cyclic AMP dependent manner. In human macrophages, P2Y11/IL-1R crosstalk with CCL20 as a prime target is controlled by phosphodiesterase 4 (PDE4), which mediates breakdown of cyclic AMP. Here, we used gene expression analysis to identify activation of CXCR4 and CXCR7 as a hallmark of P2Y11 signaling. We found that PDE4 inhibition with rolipram boosts P2Y11/IL-1R-induced upregulation of CXCR7 expression and CCL20 production in an epidermal growth factor receptor dependent manner. Using an astrocytoma cell line, naturally expressing CXCR7 but lacking CXCR4, P2Y11/IL-1R activation effectively induced and CXCR7 agonist TC14012 enhanced CCL20 production even in the absence of PDE4 inhibition. Moreover, CXCR7 depletion by RNA interference suppressed CCL20 production. In macrophages, the simultaneous activation of P2Y11 and CXCR7 by their respective agonists was sufficient to induce CCL20 production with no need of PDE4 inhibition, as CXCR7 activation increased its own and eliminated CXCR4 expression. Finally, analysis of multiple CCL chemokines in the macrophage secretome revealed that CXCR4 inactivation and CXCR7 activation selectively enhanced P2Y11/IL-1R-mediated secretion of CCL20. Altogether, our data establish CXCR7 as an integral component of the P2Y11/IL-1R-initiated signaling cascade and CXCR4-associated PDE4 as a regulatory checkpoint.

P2Y11/IL-1 receptor crosstalk controls macrophage inflammation: a novel target for anti-inflammatory strategies?

Although first cloning of the human ATP receptor P2Y11 was successful 25 years ago, the exact downstream signaling pathways of P2Y11 receptor, which can couple to Gq and Gs proteins, have remained unclear. Especially the lack of rodent models as well as the limited availability of antibodies and pharmacological tools have hampered examination of P2Y11 expression and function. Many meaningful observations related to P2Y11 have been made in primary immune cells, indicating that P2Y11 receptors are important regulators of inflammation and cell migration, also by controlling mitochondrial activity. Our recent studies have shown that P2Y11 is upregulated during macrophage development and activates signaling through IL-1 receptor, which is well known for its ability to direct inflammatory and migratory processes. This review summarizes the results of the first transcriptomic and secretomic analyses of both, ectopic and native P2Y11 receptors, and discusses how P2Y11 crosstalk with the IL-1 receptor may govern anti-inflammatory and pro-angiogenic processes in human M2 macrophages.

Intravesical BCG in bladder cancer induces innate immune responses against SARS-CoV-2

BCG is the most efficient adjuvant therapy for high-risk, non-muscle-invasive bladder cancer (NMIBC). Both innate and adaptive immune responses have been implicated in BCG-mediated effects. BCG vaccination can boost innate immune responses via trained immunity (TI), resulting in an increased resistance to respiratory viral infections. Here we evaluated for the first time whether intravesical application of BCG triggers increased immunity against SARS-CoV-2 in patients with high-risk NMIBC. Serum and peripheral blood mononuclear cells (PBMCs) from heparinized whole blood samples of 11 unvaccinated SARS-CoV-2-naïve high-risk NMIBC patients were collected at baseline and during BCG treatment in a pre-COVID-19 era. To examine B-cell or T cell-dependent adaptive immunity against SARS-CoV-2, sera were tested for the presence of SARS-CoV-2 neutralizing antibodies. Using a SARS-CoV-2 peptide pool, virus-specific T cells were quantified via IFNγ ELISpot assays. To analyze innate immune responses, mRNA and protein expression levels of pro- and anti-inflammatory cytokines were measured after a 24-hour stimulation of PBMCs with either BCG or SARS-CoV-2 wildtype. ATAC- sequencing was performed to identify a potential epigenetic reprogramming in immune cells. We neither identified SARS-CoV-2 neutralizing antibodies nor SARS-CoV-2- reactive T cells, indicating that intravesical BCG did not induce adaptive immunity against SARS-CoV-2. However, a significant increase in mRNA as well as protein expression of IL-1β, IL-6 and TNFα, which are key cytokines of trained immunity, could be observed after at least four intravesical BCG instillations. Genomic regions in the proximity of TI genes (TLR2, IGF1R, AKT1, MTOR, MAPK14, HSP90AA1) were more accessible during BCG compared to baseline. Although intravesical BCG did not induce adaptive immune responses, repetitive intravesical instillations of BCG induced circulating innate immune cells that produce TI cytokines also in response to SARS-CoV-2.

A chemokine network of T cell exhaustion and metabolic reprogramming in renal cell carcinoma

Renal cell carcinoma (RCC) is frequently infiltrated by immune cells, a process which is governed by chemokines. CD8+ T cells in the RCC tumor microenvironment (TME) may be exhausted which most likely influence therapy response and survival. The aim of this study was to evaluate chemokine-driven T cell recruitment, T cell exhaustion in the RCC TME, as well as metabolic processes leading to their functional anergy in RCC. Eight publicly available bulk RCC transcriptome collectives (n=1819) and a single cell RNAseq dataset (n=12) were analyzed. Immunodeconvolution, semi-supervised clustering, gene set variation analysis and Monte Carlo-based modeling of metabolic reaction activity were employed. Among 28 chemokine genes available, CXCL9/10/11/CXCR3, CXCL13/CXCR5 and XCL1/XCR1 mRNA expression were significantly increased in RCC compared to normal kidney tissue and also strongly associated with tumor-infiltrating effector memory and central memory CD8+ T cells in all investigated collectives. M1 TAMs, T cells, NK cells as well as tumor cells were identified as the major sources of these chemokines, whereas T cells, B cells and dendritic cells were found to predominantly express the cognate receptors. The cluster of RCCs characterized by high chemokine expression and high CD8+ T cell infiltration displayed a strong activation of IFN/JAK/STAT signaling with elevated expression of multiple T cell exhaustion-associated transcripts. Chemokinehigh RCCs were characterized by metabolic reprogramming, in particular by downregulated OXPHOS and increased IDO1-mediated tryptophan degradation. None of the investigated chemokine genes was significantly associated with survival or response to immunotherapy. We propose a chemokine network that mediates CD8+ T cell recruitment and identify T cell exhaustion, altered energy metabolism and high IDO1 activity as key mechanisms of their suppression. Concomitant targeting of exhaustion pathways and metabolism may pose an effective approach to RCC therapy.

The P2Y11 receptor of human M2 macrophages activates canonical and IL-1 receptor signaling to translate the extracellular danger signal ATP into anti-inflammatory and pro-angiogenic responses

The cytoprotective ATP receptor P2Y₁₁ is upregulated during M2 macrophage differentiation and contributes to the anti-inflammatory properties of this macrophage subset. Here, we studied P2Y₁₁-induced reprogramming of human M2 macrophages at the level of mRNA and protein expression. Upregulation of IL-1 receptor (IL-1R) and its known downstream effectors VEGF, CCL20 and SOCS3 as well as downregulation of the ATP-degrading ecto-ATPase CD39 emerged as hallmarks of P2Y₁₁ activation. The anti-inflammatory signature of the P2Y₁₁ transcriptome was further characterized by the downregulation of P2RX7, toll-like receptors and inflammasome components. P2Y₁₁-induced IL-1R upregulation formed the basis for reinforced IL-1 responsiveness of activated M2 macrophages, as IL-1α and IL-1ß each enhanced P2Y₁₁-induced secretion of VEGF and CCL20 as well as the previously reported shedding of soluble tumor necrosis factor receptor 2 (sTNFR2). Raising intracellular cyclic AMP (cAMP) in M2 macrophages through phosphodiesterase 4 inhibition enhanced P2Y₁₁-driven responses. The cAMP-binding effector, exchange protein activated by cAMP 1 (Epac1), which is known to induce SOCS3, differentially regulated the P2Y₁₁/IL-1R response because pharmacological Epac1 inhibition enhanced sTNFR2 and CCL20 release, but had no effect on VEGF secretion. In addition to cAMP, calcium and protein kinase C participated in P2Y₁₁ signaling. Our study reveals how P2Y₁₁ harnesses canonical and IL-1R signaling to promote an anti-inflammatory and pro-angiogenic switch of human M2 macrophages, which may be controlled in part by an Epac1-SOCS3 axis.

Targeting strategies in the treatment of fumarate hydratase deficient renal cell carcinoma

Fumarate hydratase (FH) - deficient renal cell carcinoma (FHdRCC) is a rare aggressive subtype of RCC caused by a germline or sporadic loss-of-function mutation in the FH gene. Here, we summarize how FH deficiency results in the accumulation of fumarate, which in turn leads to activation of hypoxia-inducible factor (HIF) through inhibition of prolyl hydroxylases. HIF promotes tumorigenesis by orchestrating a metabolic switch to glycolysis even under normoxia, a phenomenon well-known as the Warburg effect. HIF activates the transcription of many genes, including vascular endothelial growth factor (VEGF). Crosstalk between HIF and epidermal growth factor receptor (EGFR) has also been described as a tumor-promoting mechanism. In this review we discuss therapeutic options for FHdRCC with a focus on anti-angiogenesis and EGFR-blockade. We also address potential targets that arise within the metabolic escape routes taken by FH-deficient cells for cell growth and survival.

Targeting c-Met to Improve Immune Checkpoint Inhibition in Metastatic Renal Cell Carcinoma

c-Met inhibition has direct antitumor effects on proliferation, angiogenesis, and metastasis, and indirect antitumor effects via prevention of the induction of immunosuppressive mechanisms (PD-L1, TGFβ, IDO1). c-Met inhibition is key to overcome resistance to immune checkpoint inhibition and to maximize the efficacy of immunotherapy.

Control of Macrophage Inflammation by P2Y Purinergic Receptors

Macrophages comprise a phenotypically and functionally diverse group of hematopoietic cells. Versatile macrophage subsets engage to ensure maintenance of tissue integrity. To perform tissue stress surveillance, macrophages express many different stress-sensing receptors, including purinergic P2X and P2Y receptors that respond to extracellular nucleotides and their sugar derivatives. Activation of G protein-coupled P2Y receptors can be both pro- and anti-inflammatory. Current examples include the observation that P2Y14 receptor promotes STAT1-mediated inflammation in pro-inflammatory M1 macrophages as well as the demonstration that P2Y11 receptor suppresses the secretion of tumor necrosis factor (TNF)-α and concomitantly promotes the release of soluble TNF receptors from anti-inflammatory M2 macrophages. Here, we review macrophage regulation by P2Y purinergic receptors, both in physiological and disease-associated inflammation. Therapeutic targeting of anti-inflammatory P2Y receptor signaling is desirable to attenuate excessive inflammation in infectious diseases such as COVID-19. Conversely, anti-inflammatory P2Y receptor signaling must be suppressed during cancer therapy to preserve its efficacy.

Sex-specific hormone changes during immunotherapy and its influence on survival in metastatic renal cell carcinoma

Renal cell carcinoma (RCC) is a highly vascularized and immunogenic tumor, being an ideal candidate for checkpoint blockade-based immunotherapy. Accordingly, checkpoint inhibitors have demonstrated clinical efficacy in patients with metastatic RCC (mRCC). Sex-specific differences in cancer immunotherapy may be explained by the interaction of sex hormone signaling, genetic and environmental factors, affecting the innate and adaptive immune response in men and women in different ways. The aim of this prospective study was to monitor for the first time changes in sex hormones including luteinizing hormone (LH), follicle-stimulating hormone (FSH), LH/FSH ratio and 17-ß-estradiol (E2) in 22 mRCC patients (12 male and 10 female) receiving nivolumab therapy. In contrast to female patients, male patients showed a significant increase in E2 (p = 0.006) and LH/FSH ratio (p = 0.013) from the beginning of nivolumab therapy to week 12 of follow-up. Moreover, survival analysis revealed a significant negative association between LH/FSH ratio and progression-free survival (PFS) (p = 0.022) as well as between therapy response (p = 0.009) in males compared to females at interim evaluation (week 6/8). Our findings may therefore be the first reference to sex hormone changes during immunotherapy.

The human G protein-coupled ATP receptor P2Y11 is a target for anti-inflammatory strategies

Background and Purpose

The ATP receptor P2Y₁₁, which couples to G_q and G_s proteins, senses cell stress and promotes cytoprotective responses. P2Y₁₁ receptors are upregulated during differentiation of M2 macrophages. However, it is unclear whether and how P2Y₁₁ receptors contribute to the anti‐inflammatory properties of M2 macrophages.

Experimental Approach

Transcriptome and secretome profiling of ectopic P2Y₁₁ receptors was used to analyse their signalling and function. Findings were validated in human monocyte‐derived M2 macrophages. The suramin analogue NF340 and P2Y₁₁ receptor‐knockout cells confirmed that agonist‐mediated responses were specific to P2Y₁₁ receptor stimulation.

Key Results

Temporal transcriptome profiling of P2Y₁₁ receptor stimulation showed a strong and tightly controlled response of IL‐1 receptors, including activation of the IL‐1 receptor target genes, IL6 and IL8. Secretome profiling confirmed the presence of IL‐6 and IL‐8 proteins and additionally identified soluble tumour necrosis factor receptor 1 and 2 (sTNFR1 and sTNFR2) as targets of P2Y₁₁ receptor activation. Raised levels of intracellular cAMP in M2 macrophages, after inhibition of phosphodiesterases (PDE), especially PDE4, strongly increased P2Y₁₁ receptor‐induced release of sTNFR2 through ectodomain shedding mediated by TNF‐α converting enzyme (TACE/ADAM17). Both IL‐1α and IL‐1ß synergistically enhanced P2Y₁₁ receptor‐ induced IL‐6 and IL‐8 secretion and release of sTNFR2. During lipopolysaccharide‐induced activation of TLR4, which shares the downstream signalling pathway with IL‐1 receptors, P2Y₁₁ receptors specifically prevented secretion of TNF‐α.

Conclusions and Implications

Targeting P2Y₁₁ receptors activates IL‐1 receptor signalling to promote sTNFR2 release and suppress TLR4 signalling to prevent TNF‐α secretion, thus facilitating resolution of inflammation.

Lynch Syndrome: Its Impact on Urothelial Carcinoma

Lynch syndrome, known as hereditary nonpolyposis colorectal cancer (HNPCC), is an autosomal-dominant familial cancer syndrome with an increased risk for urothelial cancer (UC). Mismatch repair (MMR) deficiency, due to pathogenic variants in MLH1, MSH2, MSH6, and PMS2, and microsatellite instability, are known for development of Lynch syndrome (LS) associated carcinogenesis. UC is the third most common cancer type in LS-associated tumors. The diversity of germline variants in the affected MMR genes and their following subsequent function loss might be responsible for the variation in cancer risk, suggesting an increased risk of developing UC in MSH2 mutation carriers. In this review, we will focus on LS-associated UC of the upper urinary tract (UUT) and bladder, their germline profiles, and outcomes compared to sporadic UC, the impact of genetic testing, as well as urological follow-up strategies in LS. In addition, we present a case of metastatic LS-associated UC of the UUT and bladder, achieving complete response during checkpoint inhibition since more than 2 years.

Functional Phenotypes of Human Vγ9Vδ2 T Cells in Lymphoid Stress Surveillance

Butyrophilin and butyrophilin-like proteins select γδ T cells and direct the migration of γδ T cell subsets to distinct anatomical sites. γδ T cells expressing Vδ2 paired with Vγ9 (Vγ9Vδ2 T cells) are the predominant γδ T cell type in human peripheral blood. Vγ9Vδ2 T cells, which cannot be studied easily in vivo because they do not exist in rodents, are often referred to as innate-like T cells. The genetically recombined γδ T cell receptor (TCR) that responds to isoprenoid-derived pyrophosphates (phosphoantigens) produced by infected and malignant cells in a butyrophilin-dependent manner qualifies them as therapeutically relevant components of the adaptive immune system. On the other hand, cell-surface proteins such as the C-type lectin CD161 mark a functional phenotype of Vγ9Vδ2 T cells that mediates TCR-independent innate-like responses. Moreover, CD56 (neural cell adhesion molecule, NCAM) and the G protein-coupled receptor GPR56 define Vγ9Vδ2 T cells with increased cytolytic potential and, like CD161, may also be expressed by dendritic cells, principally facilitating the generation of an innate-like immunological synapse. In this review, we summarise current knowledge of Vγ9Vδ2 T cell functional phenotypes that are critical to lymphoid stress surveillance.

The Human G Protein-Coupled ATP Receptor P2Y11 Is Associated With IL-10 Driven Macrophage Differentiation

The G protein-coupled P2Y₁₁ receptor is known to sense extracellular ATP during inflammatory and immune responses. The dinucleotide NAD⁺ has also been proposed to be a P2Y₁₁ receptor ligand but its role is less clear. Here, we have examined for the first time human P2Y₁₁ receptor protein levels and show that the receptor was upregulated during polarization of M2 macrophages. IL-10 reinforced P2Y₁₁ receptor expression during differentiation of M2c macrophages expressing CD163, CD16, and CD274 (PD-L1). Nutlin-3a mediated p53 stabilization further increased P2Y₁₁ receptor, CD16, and PD-L1 expression. AMP-activated kinase (AMPK), which mediates anti-inflammatory effects of IL-10, and nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of the NAD⁺ salvage pathway, which is under the control of AMPK, were also required for P2Y₁₁ receptor expression. The P2Y₁₁ receptor agonist ATPγS and NAD⁺ could independently stimulate the production of IL-8 in M2 macrophages, however, only the ATPγS-induced response was mediated by P2Y₁₁ receptor. Both in a recombinant system and in macrophages, P2Y₁₁ receptor-driven IL-8 production predominantly depended on IkB kinase (IKK), and extracellular signal–regulated kinase (ERK). In conclusion, our data indicate that an AMPK-NAMPT-NAD⁺ signaling axis promotes P2Y₁₁ receptor expression during M2 polarization of human macrophages in response to IL-10. PD-L1 expressing M2c macrophages that secrete the cancer-promoting chemokine IL-8 in response to P2Y₁₁ receptor stimulation may represent an important target in checkpoint blockade immunotherapy.

Small Drops Get Fat: Unexpected Fatty Acid in Cytoplasmic Lipid Droplets

In a model of transcellular lipid biosynthesis, Guijas et al. (2016), in this issue of Cell Chemical Biology, demonstrate that lipid droplet-containing "foamy" monocytes unexpectedly accumulate 16:1n9-palmitoleic acid, which has anti-inflammatory function in vitro and in vivo. This uncommon positional isomer of 16:1n7-palmitoleic acid represents a candidate biomarker for early cardiovascular disease detection.

Rare, but Severe: Vasculitis and Checkpoint Inhibitors

In the last years, immunotherapy has become a mainstay of cancer treatment. Owing to its increasing application in clinical practice, novel and rare, but severe, immune-related adverse events such as vasculitis are now being described more frequently. Vasculitis occurs as part of a primary immune disorder but might be induced additionally by substances such as checkpoint inhibitors, which boost the immune system, and thus can also appear as an immune-related adverse event. Several lines of evidence indicate that checkpoint proteins such as programmed death-1 (PD-1) play a major role in the pathophysiology of vasculitis. Such immune checkpoints serve to prevent autoimmunity and to maintain tolerance. We present a case of pronounced vasculitis in a patient with metastatic urothelial carcinoma who received pembrolizumab, and discuss potential pathomechanisms regarding how checkpoint inhibitors can mediate immune-related vascular toxicity. PATIENT SUMMARY: In this report, we looked at potential interactions between checkpoint inhibitors and immune-associated vascular adverse events. Immunotherapy-induced changes of the immune status can favor the occurrence of vascular disease, being fatal in most cases. We conclude that the risk of progressive vascular damage and identification of patients with pre-existing vascular disease should always be borne in mind when treating patients with immunotherapy.

Mevalonate Metabolism in Cancer Stemness and Trained Immunity

Mevalonate metabolism provides cancer and immune cells with diverse products to ensure cell functionality. Similar metabolic reprogramming that raises mevalonate metabolism to higher levels appears to drive both, epithelial mesenchymal transition (EMT) of cancer cells, a reverse differentiation program that generates cancer cells with stem cell properties, and immune cell training for increased responsiveness to secondary stimulation. In this review, we address how mevalonate metabolism supports cancer development and stemness on the one hand, and on the other promotes immune responsiveness. In view of this dual nature of mevalonate metabolism, strategies to manipulate this metabolic pathway as part of anti-cancer therapies require careful analysis of risks versus benefits.

Mevalonate Metabolism in Immuno-Oncology

Immuno-oncology not only refers to the multifaceted relationship between our immune system and a developing cancer but also includes therapeutic approaches that harness the body’s immune system to fight cancer. The recognition that metabolic reprogramming governs immunity was a key finding with important implications for immuno-oncology. In this review, we want to explore how activation and differentiation-induced metabolic reprogramming affects the mevalonate pathway for cholesterol biosynthesis in immune and cancer cells. Glycolysis-fueled mevalonate metabolism is a critical pathway in immune effector cells, which may, however, be shared by cancer stem cells, complicating the development of therapeutic strategies. Additional engagement of fatty acidy oxidation, as it occurs in regulatory immune cells as well as in certain tumor types, may influence mevalonate pathway activity. Transcellular mevalonate metabolism may play an as yet unanticipated role in the crosstalk between the various cell types and may add another level of complexity. In humans, a subset of γδ T cells is specifically adapted to perform surveillance of mevalonate pathway dysregulation. While the mevalonate pathway remains an important target in immuno-oncology, in terms of personalized medicine, it may be the type or stage of a malignant disease that determines whether mevalonate metabolism requires training or attenuation.

Mevalonate metabolism governs cancer immune surveillance

The metabolic reprogramming that drives immunity engages the mevalonate pathway for cholesterol biosynthesis and protein prenylation. The importance of tight regulation of this metabolic route is reflected by the fact that too low activity impairs cellular function and survival, whereas hyperactivity can lead to malignant transformation. Here, we first address how mevalonate metabolism drives immunity and then highlight ways of the immune system to respond to both, limited and uncontrolled flux through the mevalonate pathway. Immune responses elicited by mevalonate pathway dysregulation may be harnessed to increase the clinical efficacy of current cancer therapy regimens.

Intratumoral Th2 predisposition combines with an increased Th1 functional phenotype in clinical response to intravesical BCG in bladder cancer

Th1-type immunity is considered to be required for efficient response to BCG in bladder cancer, although Th2 predisposition of BCG responders has recently been reported. The aim was to evaluate the relationship of Th1 and Th2 components in 23 patients undergoing BCG treatment. Peripheral blood, serum and urine samples were prospectively collected at baseline, during and after BCG. Th1 (neopterin, tryptophan, kynurenine, kynurenine-to-tryptophan ratio (KTR), IL-12, IFN-γ, soluble TNF-R75 and IL-2Rα) and Th2 (IL-4, IL-10) biomarkers as well as CD4 expression in T helper (Th), effector and regulatory T cells were determined. Local immune cell subsets were measured on formalin-fixed, paraffin-embedded cancer tissue by immunohistochemistry to examine expression of transcription factors that control Th1 (T-bet) and Th2-type (GATA3) immunity. We confirmed a Th2 predisposition with a mean GATA3/T-bet ratio of 5.51. BCG responders showed significantly higher levels of urinary (p = 0.003) and serum neopterin (p = 0.012), kynurenine (p = 0.015), KTR (p = 0.005), IFN-γ (p = 0.005) and IL-12 (p = 0.003) during therapy, whereas levels of IL-10 decreased significantly (p < 0.001) compared to non-responders. GATA3/T-bet ratio correlated positively with serum neopterin (p = 0.008), IFN-γ (p = 0.013) and KTR (p = 0.018) after the first BCG instillation. We observed a significant increase in CD4 expression in the Th cell population (p < 0.05), with only a modest tendency toward higher frequency in responders compared to non-responders (p = 0.303). The combined assessment of GATA3/T-bet ratio, neopterin and KTR may be a useful biomarker in predicting BCG response. Th2-promoting factors such as GATA3 may trigger Th1-type immune responses and thus contribute to the BCG success.

Ecto-ATPase CD39 Inactivates Isoprenoid-Derived Vγ9Vδ2 T Cell Phosphoantigens

In humans, Vγ9Vδ2 T cells respond to self and pathogen-associated, diphosphate-containing isoprenoids, also known as phosphoantigens (pAgs). However, activation and homeostasis of Vγ9Vδ2 T cells remain incompletely understood. Here, we show that pAgs induced expression of the ecto-ATPase CD39, which, however, not only hydrolyzed ATP but also abrogated the γδ T cell receptor (TCR) agonistic activity of self and microbial pAgs (C5 to C15). Only mevalonate-derived geranylgeranyl diphosphate (GGPP, C20) resisted CD39-mediated hydrolysis and acted as a regulator of CD39 expression and activity. GGPP enhanced macrophage differentiation in response to the tissue stress cytokine interleukin-15. In addition, GGPP-imprinted macrophage-like cells displayed increased capacity to produce IL-1β as well as the chemokine CCL2 and preferentially activated CD161-expressing CD4(+) T cells in an innate-like manner. Our studies reveal a previously unrecognized immunoregulatory function of CD39 and highlight a particular role of GGPP among pAgs.

T lymphocyte regulation by mevalonate metabolism

Whereas resting T cells, which have low metabolic requirements, use oxidative phosphorylation (OXPHOS) to maximize their generation of ATP, activated T cells, similar to tumor cells, shift metabolic activity to aerobic glycolysis, which also fuels mevalonate metabolism. Both sterol and nonsterol derivatives of mevalonate affect T cell function. The intracellular availability of sterols, which is dynamically regulated by different classes of transcription factors, represents a metabolic checkpoint that modulates T cell responses. The electron carrier ubiquinone, which is modified with an isoprenoid membrane anchor, plays a pivotal role in OXPHOS, which supports the proliferation of T cells. Isoprenylation also mediates the plasma membrane attachment of the Ras, Rho, and Rab guanosine triphosphatases, which are involved in T cell immunological synapse formation, migration, proliferation, and cytotoxic effector responses. Finally, multiple phosphorylated mevalonate derivatives can act as danger signals for innate-like γδ T cells, thus contributing to the immune surveillance of stress, pathogens, and tumors. We highlight the importance of the mevalonate pathway in the metabolic reprogramming of effector and regulatory T cells.

Stress-related and homeostatic cytokines regulate Vγ9Vδ2 T-cell surveillance of mevalonate metabolism

The potentially oncogenic mevalonate pathway provides building blocks for protein prenylation and induces cell proliferation and as such is an important therapeutic target. Among mevalonate metabolites, only isopentenyl pyrophosphate (IPP) has been considered to be an immunologically relevant antigen for primate-specific, innate-like Vγ9Vδ2 T cells with antitumor potential. We show here that Vγ9Vδ2 T cells pretreated with the stress-related, inflammasome-dependent cytokine interleukin 18 (IL-18) were potently activated not only by IPP but also by all downstream isoprenoid pyrophosphates that exhibit combined features of antigens and cell-extrinsic metabolic cues. Vγ9Vδ2 T cells induced this way effectively proliferated even under severe lymphopenic conditions and the antioxidant N-acetylcysteine significantly improved reconstitution of γδ T cells predominantly with a central memory phenotype. The homeostatic cytokine IL-15 induced the differentiation of effector cells in an antigen-independent fashion, which rapidly produced abundant interferon γ (IFNγ) upon antigen re-encounter. IL-15 induced effector γδ T cells displayed increased levels of the cytotoxic lymphocyte-associated proteins CD56, CD96, CD161 and perforin. In response to stimulation with isoprenoid pyrophosphates, these effector cells upregulated surface expression of CD107a and exhibited strong cytotoxicity against tumor cells in vitro. Our data clarify understanding of innate immunosurveillance mechanisms and will facilitate the controlled generation of robust Vγ9Vδ2 T cell subsets for effective cancer immunotherapy.

Regulation of mevalonate metabolism in cancer and immune cells

The mevalonate pathway is a highly conserved metabolic cascade and provides isoprenoid building blocks for the biosynthesis of vital cellular products such as cholesterol or prenyl pyrophosphates that serve as substrates for the posttranslational prenylation of numerous proteins. The pathway, which is frequently hyperactive in cancer cells, is considered an important target in cancer therapy, since prenylated members of the Ras superfamily are crucially involved in the control of proliferation, survival, invasion and metastasis of tumour cells. Upstream accumulation and downstream depletion of mevalonate pathway intermediates as induced for instance by aminobisphosphonates translate into different effects in cancer and immune cells. Thus, mevalonate pathway regulation can affect tumour biology either directly or exhibit indirect antitumour effects through stimulating cancer immune surveillance. The present review summarizes major effects of pharmacologic mevalonate pathway regulation in cancer and immune cells that may collaboratively contribute to the efficacy of cancer therapy.

Quality of life during dendritic cell vaccination against metastatic renal cell carcinoma

Patients with metastatic renal cell carcinoma (RCC) undergoing cytokine or targeted therapies may show a remarkable decline in quality of life (QoL). We wanted to evaluate QoL in patients with metastatic RCC undergoing therapeutic vaccination with dendritic cells (DCs). In a cross-sectional analysis, QoL was therefore assessed in RCC patients participating in three consecutive clinical trials of DC vaccination. Before the first and after the third vaccination with DCs, patients completed a QoL questionnaire (EORTC QLQ-C30, version 3). Data were transformed into scale scores and analysed using SPSS 12.0 software. Mean values of the resulting scores obtained before and after DC vaccination were compared using students t test and Wilcoxon rank-sum test. P < 0.05 was considered statistically significant. The questionnaire was completed by 55 of 71 patients (compliance rate, 77.5%) who had a median age of 58.7 years (from 30 to 75 years). No significant reductions in functioning scales including physical, emotional and social criteria as well as symptom scores, which assess typical symptoms of tumour therapies, were observed indicating that QoL remained high during DC vaccination. Significant correlations were found between overall survival and functional as well as symptom scores. Our data indicate that DC vaccination, which is a personalised treatment modality, maintains QoL and thus represents an attractive nontoxic treatment option for patients with metastatic RCC. It will be important to identify the most effective conditions of DC vaccination including combinations with other therapeutics to maximise clinical efficacy while still preserving QoL.

Novel aspects of mevalonate pathway inhibitors as antitumor agents

The mevalonate pathway for cholesterol biosynthesis and protein prenylation has been implicated in various aspects of tumor development and progression. Certain classes of drugs, such as statins and bisphosphonates, inhibit mevalonate metabolism and therefore have also been tested as antitumor agents. This concept is strongly supported by the recent finding that mutant p53, which is present in more than half of all human cancers, can significantly upregulate mevalonate metabolism and protein prenylation in carcinoma cells. The first evidence that mevalonate pathway inhibitors may have the potential to reverse the malignant phenotype has already been obtained. Moreover, recently discovered immunomodulatory properties of statins and bisphosphonates may also contribute to their known anticancer effects. Drug-induced inhibition of protein prenylation may induce sequential cellular stress responses, including the unfolded protein response and autophagy, that eventually translate into inflammasome-dependent and caspase-1-mediated activation of innate immunity. This review focuses on these novel capabilities of mevalonate pathway inhibitors to beneficially affect tumor biology and contribute to tumor immune surveillance.

C-reactive protein is a strong predictor for anaemia in renal cell carcinoma: role of IL-6 in overall survival

OBJECTIVE

• To elucidate the association of progression of advanced renal cell carcinoma with anaemia and investigate factors influencing tumor-associated anaemia.

PATIENTS AND METHODS

• We analyzed different clinical variables to study associations with anaemia in 86 metastatic renal cell carcinoma patients. • 45 (52%) of patients had already developed anaemia prior to therapy.

RESULTS

• Anaemic patients had an increase in the serum markers C-reactive protein (CRP), IL-6 and erythropoietin (EPO). In addition we observed substantial correlation between IL-6 and CRP serum levels (R = 0.639, P < 0.0001). • Univariate logistic regression analysis revealed that patients with IL-6 >10 pg/mL had a considerable increase in risk for anaemia (odds ratio 3.86, P= 0.003). • In addition, patients with CRP >0.7 mg/dL had a very strong increase in risk for anaemia (OR = 14.08, P < 0.0001). • Stepwise multivariate logistic regression analysis confirmed CRP >0.7 mg/mL as the only independent predictor for anaemia. Cox-regression modeling selected serum IL-6 as the strongest independent prognostic indicator (hazard ratio 3.58, P < 0.0001).

CONCLUSION

• Anaemia depends on serum IL-6, which is a strong inductor of CRP and regulator of the iron-transport. Serum IL-6 may be considered as a target to treat cancer-related anaemia.

Serum IgG against Candida predict survival in patients with metastatic renal cell carcinoma

BACKGROUND AND AIM

In contrast to hematologic malignancies, little is known about the role of fungi in the development and progression of solid tumors. This prompted us to analyze and correlate serum levels of different fungal IgG with survival of patients with metastatic renal cell carcinoma.

PATIENTS AND METHODS

Serum IgG to Candida sp., Saccharomyces cerevisiae and Aspergillus fumigatus were measured in a cross-sectional study in 64 patients with advanced disease. Univariate and multivariate analyses were chosen to study serum IgG as prognostic indicators.

RESULTS

Median follow-up was 29.0 months (range 0.3-122). Median overall survival of patients, which tested negative for Candida IgG, was significantly increased (median not reached, >29 months) compared with Candida IgG positive patients (17.8 months, P = 0.002). Median survival of Saccharomyces IgG negative patients was 33.1 months as opposed to 19.4 months in Saccharomyces IgG positive patients, although this difference was not significant (P = 0.281). No difference in overall survival was found between Aspergillus IgG positive patients (28.0 months) and Aspergillus IgG negative patients (29.1 months) (P = 0.181). Cox backward-stepwise regression confirmed Candida IgG as the strongest predictor of survival in metastatic renal cell carcinoma patients (risk ratio 3.27, P = 0.001, [95% CI 1.86-5.73]).

CONCLUSION

Our findings suggest that IgG antibodies directed against yeast fungi and particularly against Candida but not against mold fungi have prognostic relevance.

Serum antibodies against Saccharomyces cerevisiae: a new prognostic indicator in metastatic renal-cell carcinoma

PURPOSE

A recent study reported that a diet rich in bread and refined cereals might have an unfavorable role in the development of renal cell carcinoma (RCC). To test whether an underlying intolerance of bread ingredients is responsible for the unfavorable influence of bread on RCC, we examined patient sera for the presence of food-specific IgG.

EXPERIMENTAL DESIGN

A commercial test was used to detect food-specific IgG directed against a panel of 113 food antigens in sera of 54 patients with metastatic RCC. Kaplan-Meier estimates were used for univariate survival analysis, and differences in survival curves were assessed with the log-rank test. Multivariate survival analysis was done using a Cox regression model.

RESULTS

We found that RCC patients with elevated serum levels of IgG antibodies against S. cerevisiae, commonly known as baker's yeast and yet another bread component, have an unfavorable clinical course. Median survival of patients with high levels of S. cerevisiae IgG was only 17.8 months, whereas median survival of patients with low S. cerevisiae IgG was 43.8 months (P = 0.0022; log-rank). Multivariate survival analysis identified high levels of S. cerevisiae IgG as a strong and independent prognostic risk factor (risk ratio 4.6, P = 0.001; 95% CI 1.61-13.08).

CONCLUSIONS

Our findings indicate that serum levels of IgG against S. cerevisiae may predict survival in patients with metastatic RCC. The data suggest not cereals but baker's yeast being the critical component of bread that may cause immune deviation and impaired immunosurveillance in predisposed RCC patients.

Antigen-independent immune responses after dendritic cell vaccination

The ability of cultured, antigen-loaded dendritic cells (DCs) to induce antigen-specific T cell immunity in vivo has previously been demonstrated and confirmed. Immune monitoring naturally focuses on immunity against vaccine antigens and may thus ignore other effects of DC vaccination. Here we therefore focused on antigen-independent responses induced by DC vaccination of renal cell carcinoma patients. In addition to the anticipated response against the vaccine antigen KLH, vaccination with CD83(+) monocyte-derived DCs resulted in a strong increase in the ex vivo proliferative and cytokine responses of PBMCs stimulated with LPS or BCG. In addition, LPS strongly enhanced the KLH-induced proliferative and cytokine response of PBMCs. Moreover, proliferative and cytokine responses of PBMCs stimulated with the homeostatic cytokines IL-7 and IL-15 were also clearly enhanced after DC vaccination. In contrast to LPS induced proliferation, which is well known to depend on monocytes, IL-7 induced proliferation was substantially enhanced after monocyte depletion indicating that monocytes limit IL-7 induced lymphocyte expansion. Our data indicate that DC vaccination leads to an increase in the ex vivo responsiveness of patient PBMCs consistent with a DC vaccination induced enhancement of T cell memory. Our findings also suggest that incorporation of bacterial components and homeostatic cytokines into immunotherapy protocols may be useful in order to enhance the efficacy of DC vaccination and that monocytes may limit DC vaccination induced immunity.

Bee venom secretory phospholipase A2 and phosphatidylinositol-homologues cooperatively disrupt membrane integrity, abrogate signal transduction and inhibit proliferation of renal cancer cells

Bee venom secretory phospholipase A2 (bv-sPLA2) and phosphatidylinositol-(3,4)-bisphosphate (PtdIns(3,4)P2) act synergistically to induce cell death in tumour cells of various origins with concomitant stimulation of the immune system. Here, we investigated the mechanisms involved in such actions and examined structural requirements of PtdIns-homologues to inhibit tumour cells in combination with bv-sPLA2. Renal cancer cells were treated with bv-sPLA2 alone or in combination with PtdIns-homologues. Inhibitory effects on [(3)H] thymidine incorporation and intracellular signal transduction pathways were tested. Reaction products generated by bv-sPLA2 interaction with PtdIns(3,4)P2 were identified by mass spectrometry. Among the tested PtdIns-homologues those with a phosphate esterified to position 3 of the inositol head group, were most efficient in cooperating with bv-sPLA2 to block tumour cell proliferation. Growth inhibition induced by the combined action of bv-sPLA2 with either PtdIns(3,4)bisphosphate or PtdIns(3,4,5)trisphosphate were synergistic and accompanied by potent cell lysis. In contrast, PtdIns, which lacked the phosphate group at position 3, failed to promote synergistic growth inhibition. The combined administration of PtdIns(3,4)P2 and bv-sPLA2 abrogated signal transduction mediated by extracellular signal regulated kinase 1 and 2 and prevented transduction of survival signals mediated by protein kinase B. Surface expression of the epidermal growth factor (EGF)-receptor was reduced after PtdIns(3,4)P2-bv-sPLA2 administration and associated with a blockade of EGF-induced signalling. In addition, mass spectroscopy revealed that bv-sPLA2 cleaves PtdIns(3,4)P2 to generate lyso-PtdIns(3,4)P2. In conclusion, we suggest that the cytotoxic activity mediated by PtdIns(3,4)P2 and bv-sPLA2 is due to cell death that results from disruption of membrane integrity, abrogation of signal transduction and the generation of cytotoxic lyso-PtdIns(3,4)P2.

Interleukin-4 Promoter Polymorphisms: A Genetic Prognostic Factor for Survival in Metastatic Renal Cell Carcinoma

Purpose

Renal cell carcinoma (RCC) is considered a cytokine-responsive tumor. The clinical course of a patient may thus be influenced by the patient's capacity to produce distinct cytokines. Therefore, cytokine gene polymorphisms in RCC patients were analyzed to determine haplotype combinations with prognostic significance.

Patients and Methods

A selection of 21 single nucleotide polymorphisms within the promoter regions of 13 cytokine genes were analyzed in a cross-sectional single-center study of 80 metastatic RCC patients. Univariate and multivariate analyses and the Cox forward-stepwise regression model were chosen to assess genetic risk factors.

Results

Multivariate Cox regression analysis confirmed by a bootstrap technique identified the heterozygous IL4 genotype −589T−33T/−589C−33C as an independent prognostic risk factor (risk ratio, 3.1; P < .01; 95% CI, 1.4 to 6.9; adjusted for age, sex, and nuclear grading) in metastatic RCC patients. IL4 haplotype −589T−33T and −589C−33C were found with a frequency of 0.069 and 0.925, respectively, which represents a two-fold decrease of IL4 haplotype −589T−33T (P < .01) and an increase of IL4 haplotype −589C−33C frequency (P < .05) in metastatic RCC compared with other white reference study populations. The median overall survival was decreased 3.5-fold (P < .05) in heterozygote patients carrying IL4 haplotype −589T−33T and −589C−33C (3.78 months) compared with patients homozygote for IL4 haplotype −589C−33C (13.44 months). In addition, a linkage disequilibrium between the IL4 gene and the KIF3A gene was detected.

Conclusion

Our findings indicate that IL4 promoter variants influence prognosis in patients with metastatic RCC and suggest that genetically determined interleukin-4 (IL-4) production affects the clinical course of the disease possibly through regulation of immune surveillance.

Antitumor action and immune activation through cooperation of bee venom secretory phospholipase A2 and phosphatidylinositol-(3,4)-bisphosphate

We evaluated tumor cell growth modulation by bee venom secretory phospholipase A2 (bv-sPLA2) and phosphatidylinositol-(3,4)-bisphosphate as well as potential cooperative effects. In addition, the immunomodulatory impact of tumor cell treatment was examined by monitoring changes in phenotype and function of monocyte-derived dendritic cells (moDCs) cocultured with pretreated tumor cells. Bv-sPLA2 or phosphatidylinositol-(3,4)-bisphosphate alone displayed moderate effects on the proliferation of A498 renal cell carcinoma cells, T-47D breast cancer cells, DU145 prostate cancer cells and BEAS-2B transformed lung cells. However, when bv-sPLA2 was coadministered with phosphatidylinositol-(3,4)-bisphosphate a potent inhibition of [3H] thymidine incorporation into all tested cell lines occurred. This inhibition was due to massive cell lysis that reduced the number of cells with proliferative capacity. Importantly, tumor cell lysates generated with bv-sPLA2 plus phosphatidylinositol-(3,4)-bisphosphate induced maturation of human moDCs demonstrated by enhanced expression of CD83 and improved stimulation in allogeneic mixed leukocyte reactions. Our data demonstrate that bv-sPLA2 and phosphatidylinositol-(3,4)-bisphosphate synergistically generate tumor lysates which enhance the maturation of immunostimulatory human monocyte-derived dendritic cells. Such tumor lysates which represent complex mixtures of tumor antigens and simultaneously display potent adjuvant properties meet all requirements of a tumor vaccine.

IL-4 inhibits the TNF-alpha induced proliferation of renal cell carcinoma (RCC) and cooperates with TNF-alpha to induce apoptotic and cytokine responses by RCC: implications for antitumor immune responses

OBJECTIVE

While previous reports clearly demonstrated antiproliferative effects of IL-4 on renal cell carcinoma (RCC) in vitro, the administration of IL-4 to patients with metastatic RCC in clinical trials could not recapitulate the promising preclinical results. In the present study we wanted to examine the context of IL-4 action and to establish conditions of enhanced IL-4 efficacy.

METHODS

Primary and permanent human RCC cells were cultured in either serum-supplemented or chemically defined, serum-free culture medium in the presence or absence of cytokines. Cell proliferation was assessed as [(3)H]-thymidine incorporation. Cell apoptosis was measured using the fluorescent DNA intercalator 7-aminoactinomycin D and flow cytometry. In addition, culture media conditioned by RCC were subjected to cytokine antibody array and cytokine multiplex analysis.

RESULTS

Our results indicate that the previously reported antiproliferative effects of IL-4 are serum-dependent. Under serum-free conditions, IL-4 failed to exhibit growth-inhibitory effects or was even growth-stimulatory. In a chemically defined, serum-free medium (AIM-V), however, IL-4 inhibited the TNF-alpha induced proliferation of RCC. IL-4 and TNF-alpha synergistically induced apoptosis of RCC as well as a complex cytokine response by RCC, which included the synergistic upregulation of RANTES and MCP-1.

CONCLUSIONS

IL-4 alone has little effect on the spontaneous proliferation of RCC but can prevent the enhancement of proliferation induced by growth promoters like FBS and TNF-alpha. The concomitant growth inhibitory, apoptosis-inducing, and cytokine-enhancing effects of IL-4 in combination with TNF-alpha on RCC support the view that Th2 cytokines may be required for productive immune responses against RCC.

Lipids in dendritic cell biology: messengers, effectors, and antigens

Dendritic cells (DC) are the most professional APC, which induce and coordinate immune responses. The principal task of DC is T cell activation, although DC also interact with and regulate other cell types. The present review serves to illustrate the increasing evidence that lipids play an important role in DC biology. In addition to being fuel stores and structural components of cellular membranes such as in other cell types, lipids act as second messengers and as effectors throughout all steps of DC differentiation and regulate important DC functions. The recent finding that DC synthesize lipid antigens in response to bacterial stimulation and induce antibacterial, CD1-restricted T cells through antigenic mimicry further emphasizes the important role of lipids and DC at the blurring boundaries of innate and adaptive immunity.

Skin graft fixation by slow clotting fibrin sealant applied as a thin layer

Human fibrin sealant (FS) has been proven effective for skin grafting after severe burn, however no systematic evaluation of application conditions has been performed so far. In order to find the optimal FS amount for fixation of skin grafts to deep defects, we created four full thickness wounds (8 cmx4 cm) on the dorsum of six male pigs. Wounds were covered with unmeshed split thickness skin grafts and fixed either with a thin layer (0.05 ml/cm2) or a thick layer (0.15 ml/cm2) of fibrin sealant (FS) without additional sutures. Sutures served as controls. FS was used as a slow clotting spray (4-5 IUthrombin/ml). Outcome measurements revealed that hematoma formation (day of surgery) was more extensive and occurred more frequently in the suture group as compared to FS 0.05 ml/cm2 (p<0.05). Areas of graft dislocation tended to be larger in the suture group versus the FS 0.05 ml/cm2. The FS 0.05 ml/cm2 graft take on day 5 appeared to be enhanced in comparison to the suture group. Excellent outcome was notable on the final observation day (day 21) in the FS 0.05 ml/cm2 group with a take of 99.7% (IQR 96.1-100%). Corresponding values in the FS 0.15 ml/cm2 group were 96.9% (IQR 92.2-99%) and 95.9% (IQR 93.2-98%) in the suture group. The results indicate, that the usage of a sprayed thin FS layer (0.05 ml/cm2) in a slow clotting rate (4-5 IUthrombin/ml) is an appropriate fixation method in split thickness skin transplantation.

Bilateral lavage with diluted surfactant improves lung function after unilateral lung contusion in pigs*

OBJECTIVE

This study evaluates the effects of bronchoalveolar lavage with diluted surfactant on unilateral lung contusion-induced lung dysfunction.

DESIGN

Randomized prospective animal study.

SETTING

An animal laboratory.

SUBJECTS

Twenty adult pigs, weighing 25-35 kg.

INTERVENTIONS

Animals were randomly assigned to controls and surfactant treatment. Bilateral lavage with surfactant treatment began 30 mins after unilateral lung contusion. Then 25 mg/kg of body weight diluted Curosurf (5 mg/mL) was applied in a volume of 5 mL/kg of body weight. Observation time was 8 hrs postinjury.

MEASUREMENTS AND MAIN RESULTS

The Pao2/Fio2 ratio fell from 500 to 250 and then recovered gradually in controls and surfactant-treated pigs. After another 4 hrs, the Pao2/Fio2 ratio deteriorated again in controls, but not in surfactant-treated animals. Total compliance fell by 50% after injury but was completely restored by surfactant treatment. Lung contusion increased the median number of neutrophils in bronchoalveolar lavage fluid from 2% to 30% of total cells and peaked >60% at 480 mins in the contused lungs of control pigs. Surfactant-treated pigs had 40% neutrophils at 480 mins without reaching significant difference to controls. The leukocyte neutral proteinase inhibitor increased to 500 ng/mL at 30 mins postinjury in the contused lungs and increased to 2000 ng/mL after surfactant treatment.

CONCLUSIONS

Bilateral bronchoalveolar lavage with diluted surfactant can effectively improve lung function after experimental unilateral lung contusion in pigs.

Up-regulation of functional chemokine receptor CCR3 in human renal cell carcinoma

There is increasing evidence that chemokines and chemokine receptors are causally involved in tumorigenesis by facilitating tumor proliferation and metastasis. Little is known about the possible function of chemokine receptors in the development and progression of renal cell carcinoma (RCC). We, therefore, analyzed the expression of chemokine receptors in tumor specimens and adjacent healthy kidney tissues [normal kidney cell (NKC)] from 10 RCC patients. We also characterized the permanent RCC cell line A-498. CCR6, CXCR2, and CXCR3 were consistently expressed by both malignant cells and NKCs. A-498 displayed additional expression of CXCR4. Importantly, the expression of CCR3 was almost absent on NKCs but clearly enhanced in a substantial proportion of RCC specimens. The primary CCR3 ligand, eotaxin-1/CCL11, induced intracellular Ca2+ mobilization, receptor internalization, and proliferation in A-498 cells confirming signaling competence of RCC-associated CCR3. In addition, we screened tumor tissue sections of 219 patients and found that 28% (62 of 219) expressed the CCR3 receptor. The presence of CCR3 in tumor samples seemed to correlate with the grade of malignancy. Previous work has established that eotaxin-1 expression is induced by tumor necrosis factor-alpha, a cytokine known to be present in RCC tissue. Our data, therefore, supports a scenario in which eotaxin-1 as part of tumor-associated inflammation promotes progression and dissemination of CCR3-positive RCC.

Allogeneic dendritic cell vaccination against metastatic renal cell carcinoma with or without cyclophosphamide

In this phase I/II study, we evaluated the feasibility, safety and efficacy of allogeneic dendritic cells (DCs) with or without cyclophosphamide in the treatment of patients with metastatic renal cell carcinoma (RCC). Immunomagnetic beads were used to isolate CD14(+) monocytes from healthy donor leukapheresis products, and CD83(+) antigen-pulsed monocyte-derived DCs (moDCs) loaded with tumor lysate and keyhole limpet hemocyanin (KLH) were generated. Twelve patients were treated with allogeneic moDCs alone, while ten patients also received cyclophosphamide on days 4 and 3 prior to vaccination. Of the 22 patients enrolled, 20 received full treatment consisting of at least three vaccinations at monthly intervals. Two mixed responses with substantial tumor regression were observed. In 3 patients, disease stabilization occurred, in 13 patients disease progressed and 4 patients were lost to follow-up. Overall, immune responses against KLH and tumor lysate were weak or absent; however, the strongest increases in antigen-independent and KLH-specific responses were observed in the 2 patients with mixed responses. In addition, 1 of them showed a substantial increase in oncofetal antigen (OFA)-specific IFN-gamma production. Importantly, the 2 mixed responders and 1 patient with stable disease belonged to the cyclophosphamide group. Median overall survival in the cyclophosphamide group was 23.2 and 20.3 months in the group that received allogeneic moDCs alone. Allogeneic immunotherapy with moDCs is feasible and well tolerated. However, the immunogenicity of allogeneic moDCs is clearly less pronounced than that of autologous moDC immunotherapy. Cyclophosphamide may have the capacity to augment DC-induced antitumor immunity.

Monitoring of CD4+ and CD8+ T-cell responses after dendritic cell-based immunotherapy using CFSE dye dilution analysis

CFSE dye dilution analysis and [3H] thymidine incorporation were used side by side to assess proliferative responses of peripheral blood mononuclear cells (PBMCs) after vaccination of renal cell carcinoma patients (n=6) with antigen-loaded dendritic cells. Immune responses against the control antigen keyhole limpet hemocyanin (KLH) were induced in all patients. While [3H] thymidine incorporation revealed a 4 to 977-fold increase in KLH-induced proliferation (mean: 209-fold), CFSE-labeling experiments demonstrated that the KLH-responsive population of postvaccination PBMCs represented 7-53% (mean: 23%). Combining CFSE-labeling with T-cell subset analysis confirmed the presence of CD4+ KLH-reactive T cells but also revealed a substantial population of CD8+ KLH-reactive T cells in one patient as well as minor populations of CD8+ KLH-reactive T cells in three other patients. Our data indicate that CFSE dye dilution analysis is a valuable tool for immune monitoring after dendritic cell vaccination.

Dendritic-cell activation by secretory phospholipase A2

Dendritic cells (DCs), also referred to as the sentinels of the immune system, induce and coordinate important functions of immune surveillance. DCs acquire immunity-initiating capacity only after a process of maturation usually induced by ligands that bind to members of the tumor necrosis factor (TNF) or toll-like receptor families. Secretory phospholipase A2 (sPLA2), which hydrolyzes the sn-2 ester bond of glycerophospholipids, regulates a variety of cellular functions including migration of endothelial cells and neurite outgrowth. In the present study we investigated the role of sPLA2 in DC biology. We report that human monocyte-derived DC cultures lack sPLA2 activity but respond to exogenous sPLA2. sPLA2 alone and in cooperation with TNF-α and interleukin 1 β (IL-1β) induced fatty acid release from DC membranes, which was accompanied by upregulation of surface markers and by an increase in the migratory and immunostimulatory capacity of the DCs. Our findings indicate that secreted enzymes such as sPLA2 can contribute to DC maturation and emphasize the role of lipid mediators in the regulation of immune responses. This observation may also have implications for DC-based vaccine development.

Contemporary definitions of tumor specific antigens, immunogens and markers as related to the adaptive responses of the cancer-bearing host

This review describes clear parameters for designating the correct use of the term Tumor Rejection Antigen [TRA] to define the role of tumor cell constituents which activate adaptive anti-tumor immune reactions in the cancer-bearing host. This is important, especially in defining immunogens which activate the patient's cytotoxic T-cells that are important to immunotherapeutic applications in human cancer treatment. The focus of the review is to correctly delineate the immunogenic properties of 37 kDa oncofetal antigen [OFA], one of only a few true TRAs expressed on human and experimental rodent cancers. The purpose of this review is to provide a background for publication reviewers, journal and text editors, and scientists reporting on TRAs to avoid creating further confusion that has proliferated in the cancer literature to imply traits of so-called tumor-associated antigens that do not qualify as TRAs.

The cyclopentenone prostaglandin PGA2 costimulates the maturation of human dendritic cells

OBJECTIVE

Dendritic cells (DCs), also referred to as the sentinels of the immune system, induce and coordinate important functions of immune surveillance. Prostaglandin E2 (PGE2), a member of the eicosanoid family of arachidonic acid derivatives, is widely used to enhance the TNF-alpha-driven maturation of human monocyte-derived DCs (moDCs) both in basic research and in clinical settings. However, PGE2 is known to rapidly undergo nonenzymatic dehydration to produce PGA2, a member of the cyclopentenone PGs, which have been implicated in anti-inflammatory processes.

METHODS

In a side-by-side analysis we therefore compared the influence of PGE2 and PGA2 on the TNF-alpha-induced maturation of human moDCs. Phenotypic changes, migratory responses towards MIP-3beta, and T-cell responses induced by the differentially matured moDCs were assessed.

RESULTS

We found that PGA2 is nearly as potent as PGE2 in costimulating the TNF-alpha-induced phenotypic maturation of human moDCs. Both PGE2 and PGA2 further enhanced the migratory and T-cell-stimulatory capacity of TNF-alpha-treated moDCs. Maturation of moDCs with either PGE2 or PGA2 resulted in enhanced IFN-gamma, TNF-alpha, and IL-5 production and repressed IL-10 production in allogeneic mixed leukocyte cultures. PGE2 was always more potent than PGA2.

CONCLUSIONS

Our data suggest that some of the effects attributed to PGE2 may in fact be mediated by its degradation product PGA2. This work also demonstrates that cyclopentenone PGs may have pro-inflammatory properties and that both PGE2 and PGA2 can contribute to the development of Th1-type immune responses.