There is growing evidence that chronic stress and other behavioral conditions are associated with cancer pathogenesis and progression, but the mechanisms involved in this association are poorly understood. We examined the effects of two mediators of stress, norepinephrine and epinephrine, on the activation of signal transducer and activator of transcription-3 (STAT3), a transcription factor that contributes to many promalignant pathways. Exposure of ovarian cancer cell lines to increasing concentrations of norepinephrine or epinephrine showed that both independently increased levels of phosphorylated STAT3 in a dose-dependent fashion. Immunolocalization and ELISA of nuclear extracts confirmed increased nuclear STAT3 in response to norepinephrine. Activation of STAT3 was inhibited by blockade of the B1-and B2-adrenergic receptors with propranolol, and by blocking protein kinase A with KT5720, but not with the A receptor blockers prazosin (A1) and/or yohimbine (A2). Catecholamine-mediated STAT3 activation was not inhibited by pretreatment with an anti-interleukin 6 (IL-6) antibody or with small interfering RNA (siRNA)-mediated decrease in IL-6 or gp130. Regarding the effects of STAT3 activation, exposure to norepinephrine resulted in an increase in invasion and matrix metalloproteinase (MMP-2 and MMP-9) production. These effects were completely blocked by STAT3-targeting siRNA. In mice, treatment with liposome-incorporated siRNA directed against STAT3 significantly reduced isoproterenolstimulated tumor growth. These studies show IL-6-independent activation of STAT3 by norepinephrine and epinephrine, proceeding through the B1/B2-adrenergic receptors and protein kinase A, resulting in increased matrix metalloproteinase production, invasion, and in vivo tumor growth, which can be ameliorated by the down-regulation of STAT3. [Cancer Res 2007;67(21):10389-96]

The response of human peripheral blood mononuclear cells (MNC) to Aspergillus fumigatus in vitro was evaluated. In studies of the proliferative response of MNC from 18 healthy donors to heat-killed A. fumigatus conidia, 15 displayed a significant response, with a stimulation index (SI) between 4 and 193. In contrast, all donors displayed a positive response to Candida albicans blastoconidia (SI ranged from 10 to 224). Despite the variability in reactivity to A. fumigatus conidia, the response of a particular individual was stable when retested over periods of 1-2 weeks. Supernatant from cocultures of A. fumigatus conidia with MNC contained increased levels of interferon-gamma, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha, and interleukin (IL)-2, compared with unstimulated cells, but not IL-10 or IL-4. In addition, A. fumigatus induced lymphocyte surface expression of adhesion/activation-associated molecules. These results suggest that lymphocytes may contribute to host defense against Aspergillus by generating a Th1-type response.

We studied the potential of multidimensional flow cytometry to evaluate the frequency and maturation/activation status of dendritic cells in minimally manipulated peripheral blood mononuclear cell preparations (i.e., only separated on Ficoll-Hypaque) of normal donors and cancer patients. A rare subset of HLA-DR+ leukocytes (less than 1% mononuclear cells) was detected in blood of normal donors that displayed all the features of dendritic cells: these cells had high forward-light-scatter characteristics and coexpressed CD4, CD86 and CD54 surface antigens, but lacked the lineage-associated surface markers of T cells, B cells, monocytes, granulocytes or NK i.e. they were CD3-, CD19-, CD20-, CD14-, CD11b-, CD16-, CD56-). These physical and phenotypic properties were virtually identical to those of immunomagnetically sorted leukocytes characterized as dendritic-cells on the basis of morphology, phenotype and high stimulatory activity in allogeneic mixed-lymphocyte cultures. Using this flow-cytometric approach we observed that the frequency of dendritic cell-like cells in peripheral blood mononuclear cell specimens of cancer patients receiving chemotherapy alone or those recovering from stem cell transplantation was significantly lower than that of normal individuals (mean +/- SE: 0.36 +/- 0.05%, 0.14 +/- 0.06%, and 0.75 +/- 0.04% respectively). Multidimensional flow-cytometric analysis of dendritic cells might represent an important new tool for assessing immunocompetence, and for monitoring the effects of therapeutic regimens on the immune system.

Summary:Lymphocytes play a major role in host defense against Aspergillus, but little is known about the contribution of dendritic cells (DC) to antifungal immunity in humans. We have observed that DC derived from normal volunteers phagocytose heat-killed A. fumigatus conidia. Following 24 h of exposure to the fungus, DC displayed an increase in the mean fluorescence intensity of HLA-DR, CD80, and CD86, and an increase in the percentage of CD54 + cells. These DC also displayed increased production of IL-12. DC derived from CD34 + progenitors or monocytes stimulated autologous lymphocytes to proliferate and produce high levels of interferon-␥, but not interleukin-10, in response to fungal antigen. DC generated from CD34 + progenitors collected prior to autologous or allogeneic stem cell transplantation also partially restored the in vitro antifungal proliferative response of lymphocytes obtained from patients 1 month after transplantation. These results suggest that DC are important to host-response to A. fumigatus, and that ex vivo-generated DC might be useful in restoring or enhancing the antifungal immunity after hematopoietic stem cell transplantation. Bone Marrow Transplantation (2001) 27, 647-652. Keywords: fungi; dendritic cell; immune reconstitution; Candida; AspergillusThe ubiquitous mould Aspergillus rarely causes disease in healthy individuals but poses a serious threat to hematopoietic stem cell transplant recipients. [1][2][3] It is the most common etiology of non-Candida fungal infections occurring in these patients, and the case-fatality rate for invasive aspergillosis exceeds 80%. Although prolonged neutropenia is a well-established risk factor for Aspergillus infections, the majority of infections in the allogeneic setting become clinically evident well after engraftment, 2 suggesting that cell-mediated immunity plays an important role in protec- tion against this pathogen. Indeed, animal studies demonstrated that a Th1 response was associated with resistance to induction of experimental Aspergillus infection, 4 and methods stimulating a Th1 response were successful in inducing anti-Aspergillus immunity. 5 We 6 and others 7 have reported that a substantial proportion of blood and marrow transplant recipients have a deficiency in the number of circulating dendritic cells (DC) in the early post-transplant period. To overcome the potential effects of DC deficiency on immune reconstitution post transplant, DC-based vaccines have been used to induce T cell-mediated immunity to tumor early after transplantation. 8 However, despite the importance of DC in immunity, there is virtually no information regarding the role of human DC in resistance to aspergillosis. We have therefore evaluated the phagocytic capacity of human DC for A. fumigatus conidia, the cytokine response of human DC after exposure to A. fumigatus conidia, and the immunostimulatory competence of A. fumigatus conidia-pulsed DC for autologous lymphocytes from blood stem cell transplant recipients. The results of our studies suggest that DC ...