Bisphosphonates are mainly used for the inhibition of osteoclast-mediated bone resorption but also have been shown to induce ␥␦ T-cell activation. Using IL-2-primed cultures of CD56 ؉ peripheral blood mononuclear cells, we show here that zoledronic acid (zoledronate) could induce IFN-␥ production not only in ␥␦ T lymphocytes but, surprisingly, also in natural killer (NK) cells in a manner that depended on antigen-presenting cells, which share properties of inflammatory monocytes and dendritic cells (DCs; here referred to as DC-like cells). In the presence of ␥␦ T lymphocytes, DC-like cells were rapidly eliminated, and NK cell IFN-␥ production was silenced. Conversely, in the absence of ␥␦ T lymphocytes, DClike cells were spared, allowing NK cell IFN-␥ production to proceed. ␥␦ T cellindependent NK cell activation in response to zoledronate was because of downstream depletion of endogenous prenyl pyrophosphates and subsequent caspase-1 activation in DC-like cells, which then provide mature IL-18 and IL-1␤ for the activation of IL-2-primed NK cells. Pharmacologic inhibition of caspase-1 almost abolished IFN-␥ production in NK cells and ␥␦ T lymphocytes, indicating that caspase-1-mediated cytokine maturation is the crucial mechanism underlying innate lymphocyte activation in response to zoledronate. (Blood. 2011; 118(10):2743-2751) IntroductionThe bisphosphonates zoledronate and pamidronate are approved by the Food and Drug Administration for the treatment of metastatic bone disease of hematopoietic tumors such as multiple myeloma 1,2 and nonhematopoietic tumors such as breast 3 and prostate cancer. 4 Inhibition of farnesyl pyrophosphate synthase, an enzyme of the mevalonate pathway for cholesterol biosynthesis and protein prenylation, 5 is one important mechanism for bisphosphonate effects on bone resorption. 1,4 Inhibition of farnesyl pyrophosphate synthase leads to farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) deprivation and the subsequent failure to perform farnesylation and geranylgeranylation of small guanosine triphosphatases (GTPases) of the RAS superfamily. Inhibition of RAS signaling because of the disruption of membrane anchoring of these GTPases eventually prevents osteoclast-mediated bone resorption. 6,7 In addition to their effects on bone metabolism, bisphosphonates may have immunomodulatory effects, particularly on the innate immune system. [8][9][10][11] Evidence for the stimulation of ␥␦ T lymphocytes by bisphosphonates was obtained when expansion of ␥␦ T lymphocytes was observed in patients who had acute-phase reactions after their first treatment with pamidronate. 12 Inhibition of FPP synthase by bisphosphonates leads to the accumulation of isopentenyl pyrophosphate that can be specifically recognized by ␥␦ T lymphocytes expressing the V␦2V␥9 T-cell receptors. 13 Hematopoietic tumor cell lines such as Daudi (Burkitt lymphoma) or RPMI 8226 (myeloma) are specifically recognized and lysed by these ␥␦ T lymphocytes in vitro. 14,15 Moreover, ␥␦ T lymphocytes have recently been...

Statins are inhibitors of cholesterol biosynthesis and protein prenylation that also have been studied in cancer therapy and chemoprevention. With regard to natural killer (NK) cells, only inhibitory effects of statins such as suppression of granule exocytosis have been reported so far. In this study, we show that statins can cooperate with IL-2 to potently induce the activation of CD56 dim NK cells in a synergistic, time-and dose-dependent fashion. Supplementation experiments revealed that the statin effect was specific to inhibition of their target hydroxymethylglutaryl coenzyme A reductase and that downstream depletion of geranylgeranyl pyrophosphate was responsible for cooperating with IL-2 in NK cell activation. Mechanistic studies revealed that CD56

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 Ca 2+ 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-1expression is induced by tumor necrosis factor-a, 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.Cancers of the kidney account for 2% to 3% of all malignancies and have a peak incidence in the fifth and sixth decades of life. Renal cell carcinoma (RCC) is the most common malignant renal tumor with an incidence of 4 to 5 in 100 people. At diagnosis, 20% to 30% of the patients have metastatic disease and even a higher percentage of patients develop metachronous metastases after nephrectomy. When in metastatic progression, systemic therapies of RCC are largely ineffective in impacting disease response or patient survival. Therefore, defining the factors involved in disease progression and metastasis constitutes a necessary approach in the development of effective therapies.Multiple factors are known to contribute to the development and progression of neoplasias in general. Among them, chemokines are increasingly being recognized as key players (for reviews, see refs. 1, 2). Chemokines constitute a family of small (8-10 kDa) secreted proteins that act in paracrine or autocrine fashion. Most chemokines are expressed in response to stimuli [e.g., tumor necrosis factor-a (TNF-a) or IFN-g], but constitutive expression might also occur in a tissue-specific manner. Chemokines exert their activity via interaction with a large family of seven-transmembrane-spanning G protein -coupled receptors (3). There are f20 chemokine receptors described thus far and many of the receptors exhibit widespread binding properties. Thus, several chemokines can signal through the same receptor.Originally, chemokines were discovered as chemoattractants and activators of ...

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.