Patrizia Moser

Interleukin-6 stimulation of growth of prostate cancer in vitro and in vivo through activation of the androgen receptor

It is hypothesized that ligand-independent activation of the androgen receptor is one of the mechanisms implicated in tumour progression. However, supportive evidence is limited to the effect of HER-2/neu that stimulates prostate cancer progression through activation of the androgen receptor. In the present study, we have asked whether the proinflammatory cytokine interleukin-6 (IL-6), which is known to stimulate androgen receptor activity and expression of its downstream target genes, may also induce growth of androgen-sensitive cells. We have found that IL-6 differentially regulates proliferation of LAPC-4 and MDA PCa 2b cells. In MDA PCa 2b cells, growth stimulation by IL-6 was reversed by administration of either the non-steroidal anti-androgen bicalutamide or the inhibitor of the mitogen-activated protein kinase pathway PD98059. Neither cell line was found to express endogenous IL-6. Interestingly, the treatment of those prostate cancer cells did not increase phosphorylation of STAT3. The effect of IL-6 on stimulation of androgen receptor activity in MDA PCa 2b cells was lower than that of androgen, comparable with findings reported by other researchers. However, growth of MDA PCa 2b xenografts in castrated animals treated with IL-6 was similar to that in non-castrated animals. In addition, bicalutamide showed an inhibitory effect on IL-6-regulated growth in vivo. Taken together, data in the present study demonstrate that IL-6 may cause growth of androgen receptor-positive tumours in vitro and in vivo through activation of the androgen receptor.

Macroscopic postmortem findings in 235 surgical intensive care patients with sepsis.

BACKGROUND: Although detailed analyses of the postmortem findings of various critically ill patient groups have been published, no such study has been performed in patients with sepsis. In this retrospective cohort study, we reviewed macroscopic postmortem examinations of surgical intensive care unit (ICU) patients who died from sepsis or septic shock. METHODS: Between 1997 and 2006, the ICU database and autopsy register were reviewed for patients who were admitted to the ICU because of sepsis/septic shock, or who developed sepsis/septic shock at a later stage during their ICU stay and subsequently died from of sepsis/septic shock. Clinical data and postmortem findings were documented in all patients. RESULTS: Postmortem results of 235 patients (84.8%) were available for statistical analysis. The main causes of death as reported in the patient history were refractory multiple organ dysfunction syndrome (51.5%) and uncontrollable cardiovascular failure (35.3%). Pathologies were detected in the lungs (89.8%), kidneys/urinary tract (60%), gastrointestinal tract (54%), cardiovascular system (53.6%), liver (47.7%), spleen (33.2%), central nervous system (18.7%), and pancreas (8.5%). In 180 patients (76.6%), the autopsy revealed a continuous septic focus. The most common continuous foci were pneumonia (41.3%), tracheobronchitis (28.9%), peritonitis (23.4%), uterine/ovarial necrosis (9.8% of female patients), intraabdominal abscesses (9.1%), and pyelonephritis (6%). A continuous septic focus was observed in 63 of the 71 patients (88.7%) who were admitted to the ICU because of sepsis/septic shock and treated for longer than 7 days. CONCLUSIONS: Relevant postmortem findings explaining death in surgical ICU patients who died because of sepsis/septic shock were a continuous septic focus in approximately 80% and cardiac pathologies in 50%. The most frequently affected organs were the lungs, abdomen, and urogenital tract. More diagnostic, therapeutic and scientific efforts should be launched to identify and control the infectious focus in patients with sepsis and septic shock.

Erythropoietin Contrastingly Affects Bacterial Infection and Experimental Colitis by Inhibiting Nuclear Factor-κB-Inducible Immune Pathways

Summary Erythropoietin (EPO) is the principal cytokine regulating erythropoiesis through its receptor, EPOR. Interestingly, EPORs are also found on immune cells with incompletely understood functions. Here, we show that EPO inhibits the induction of proinflammatory genes including tumor necrosis factor (TNF)-α and inducible nitric oxide (NO) synthase in activated macrophages, which is mechanistically attributable to blockage of nuclear factor (NF)-κB p65 activation by EPO. Accordingly, in systemic Salmonella infection, treatment of mice with EPO results in reduced survival and impaired pathogen clearance because of diminished formation of anti-microbial effector molecules such as TNF-α and NO. However, neutralization of endogenous EPO or genetic ablation of Epor promotes Salmonella elimination. In contrast, in chemically induced colitis, EPO-EPOR interaction decreases the production of NF-κB-inducible immune mediators, thus limiting tissue damage and ameliorating disease severity. These immune-modulatory effects of EPO may be of therapeutic relevance in infectious and inflammatory diseases.

Nitric oxide–mediated regulation of ferroportin-1 controls macrophage iron homeostasis and immune function in Salmonella infection

NOS2-derived nitric oxide drives ferroportin-1–mediated iron export in Salmonella-infected macrophages, thus limiting bacterial growth.

TROP2: a novel prognostic marker in squamous cell carcinoma of the oral cavity

Squamous cell carcinoma is by far the most common type of cancer of the oral cavity, representing more than 90% of all oral cancers. Despite refinement of surgical techniques and adjuvant therapies, the prognosis for patients with oral squamous cell carcinoma remains poor. Identification of prognostic factors related to tumor biology might improve this assessment. Recently, the human trophoblast cell-surface antigen TROP2 was found to be highly expressed in colorectal cancer, correlating with aggressiveness and poor prognosis. Thus, the aim of this study was to investigate TROP2 expression and its prognostic impact in oral squamous cell carcinoma patients. TROP2 expression was examined by immunohistochemistry in a series of 90 patients on a tissue microarray of paraffin-embedded specimens. Survival was calculated using Kaplan–Meier estimates. Parameters found to be of prognostic significance in univariate analysis were verified in a multivariate Cox regression model. TROP2 overexpression was observed in 52 (58%) of the tumor samples. Kaplan–Meier curves showed that TROP2 overexpression was significantly associated with decreased overall survival (P<0.01). Overall survival gradually worsened with increasing TROP2 scores. By univariate analyses, no correlation with conventional clinicopathological features was found. Multivariate Cox regression analysis revealed TROP2 overexpression to be an independent factor predictive of poor disease outcome (P<0.01). These results demonstrate that TROP2 overexpression is an independent prognostic marker in patients with oral squamous cell carcinoma. TROP2 overexpression was detectable in 58% of the tumor samples, indicating it to be a potential novel therapeutic target in squamous cell carcinoma of the oral cavity.

Effects of weight loss induced by bariatric surgery on hepatic adipocytokine expression

BACKGROUND/AIMS Adipocytokines play a key role in the pathophysiology of non-alcoholic fatty liver diseases (NAFLD). Whereas adiponectin has mainly anti-inflammatory functions, leptin, resistin and pre-B cell enhancing factor (PBEF)/Nampt/visfatin are considered as mainly pro-inflammatory mediators regulating metabolic and immune processes. METHODS We prospectively examined the effect of weight loss on systemic levels and/or hepatic expression of adiponectin/adiponectin receptors, leptin/leptin receptors, resistin and PBEF/Nampt/visfatin. Severely obese patients underwent laparoscopic adjustable gastric banding (LABG) and serum samples (n=30) were collected before, and after 6 and 12 months. Paired liver biopsies (before and 6 months after LABG) were obtained from 18 patients. RESULTS Bariatric surgery improved insulin resistance, abnormal liver function tests and liver histology. Pronounced weight loss after 6 and 12 months was accompanied by a significant increase in serum adiponectin levels whereas both leptin and PBEF/Nampt/visfatin levels decreased. Resistin serum levels increased after 6 months but fell below baseline values after 12 months. Liver mRNA expression of adiponectin increased slightly after 6 months whereas leptin mRNA expression did not change. Interestingly, weight loss resulted in a significant decrease of hepatic mRNA expression of resistin, PBEF/Nampt/visfatin and both leptin receptor isoforms while expression of type 1 and 2 adiponectin receptor was not affected. Liver immunohistochemistry performed on index and follow-up liver biopsies revealed an increase in adiponectin staining, showed no effect on resistin/leptin positivity, and demonstrated a decrease in PBEF/Nampt/visfatin immunoreactivity. CONCLUSIONS Weight loss after LABG surgery drives the adipocytokine milieu towards a more anti-inflammatory direction both systemically and in the liver.

The antiapoptotic effect of IL-6 autocrine loop in a cellular model of advanced prostate cancer is mediated by Mcl-1

Levels of the proinflammatory cytokine interleukin-6 (IL-6) are increased in therapy-resistant prostate cancer. IL-6 has been considered a positive growth factor in late-stage prostate cancer cells and a potential target for therapeutic interference. Effects of inhibition of IL-6 on cell survival were studied in LNCaP-IL6+ cells, a model system for advanced prostate cancer, which produce IL-6. We show that the autocrine IL-6 loop is responsible for resistance to apoptosis and increased cellular levels of myeloid cell leukemia-1 (Mcl-1) protein, an antiapoptotic member of the Bcl-2 family. Treatment of cells with a chimeric anti-IL-6 antibody (CNTO 328) led to the induction of apoptosis and downregulation of Mcl-1 protein levels. Specific knockdown of Mcl-1 gene expression by small interfering RNA also yielded an increase in apoptosis of LNCaP-IL-6+ cells. Vice versa, inactivation of IL-6 autocrine loop had no influence on apoptosis levels in the absence of Mcl-1, thus suggesting this molecule as a mediator of the survival action of IL-6. Mcl-1 protein regulation by the endogenous cytokine directly involved the extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase pathway. Our data support the concept of anti-IL-6 targeted therapy in therapy-resistant prostate cancer.

The anti-interleukin-6 antibody siltuximab down-regulates genes implicated in tumorigenesis in prostate cancer patients from a phase I study†‡§

Interleukin‐6 (IL‐6) is associated with prostate cancer morbidity. In several experimental models, IL‐6 has been reported to have anti‐apoptotic and pro‐angiogenic effects. Siltuximab (CNTO 328) is a monoclonal anti‐IL‐6 antibody which has been successfully applied in several models representing prostate cancer. This study was designed to assess preliminary safety of siltuximab in patients with early prostate cancer.

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-α, 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.

High-fat diet causes iron deficiency via hepcidin-independent reduction of duodenal iron absorption ☆ ☆☆

Obesity is often associated with disorders of iron homeostasis; however, the underlying mechanisms are not fully understood. Hepcidin is a key regulator of iron metabolism and may be responsible for obesity-driven iron deficiency. Herein, we used an animal model of diet-induced obesity to study high-fat-diet-induced changes in iron homeostasis. C57BL/6 mice were fed a standard (SD) or high-fat diet (HFD) for 8 weeks, and in addition, half of the mice received high dietary iron (Fe+) for the last 2 weeks. Surprisingly, HFD led to systemic iron deficiency which was traced back to reduced duodenal iron absorption. The mRNA and protein expressions of the duodenal iron transporters Dmt1 and Tfr1 were significantly higher in HFD- than in SD-fed mice, indicating enterocyte iron deficiency, whereas the mRNA levels of the duodenal iron oxidoreductases Dcytb and hephaestin were lower in HFD-fed mice. Neither hepatic and adipose tissue nor serum hepcidin concentrations differed significantly between SD- and HFD-fed mice, whereas dietary iron supplementation resulted in increased hepatic hepcidin mRNA expression and serum hepcidin levels in SD as compared to HFD mice. Our study suggests that HFD results in iron deficiency which is neither due to intake of energy-dense nutrient poor food nor due to increased sequestration in the reticulo-endothelial system but is the consequence of diminished intestinal iron uptake. We found that impaired iron absorption is independent of hepcidin but rather results from reduced metal uptake into the mucosa and discordant oxidoreductases expressions despite enterocyte iron deficiency.