Sellar collision tumor involving pituitary gonadotroph adenoma and chondroma: a potential clinical diagnosis

We report on a 74-year-old male patient who presented with progressive neuroophthalmologic symptoms soon after the administration of a long-acting gonadotropin-releasing hormone agonist for treatment of a prostate cancer. Imaging revealed a destructively growing and extensively calcified sellar mass inconsistent with a pituitary adenoma. A transseptal transsphenoidal tumor mass reduction yielded a histological diagnosis of a collision tumor comprised of a gonadotroph adenoma intermingled with osteochondroma. We discuss a potential causal relationship between the administration of the long-acting gonadotropin-releasing hormone agonist and the sudden appearance of the previously unsuspected sellar lesion. Although the association of these two tumors is very likely coincidental, the possibility of causal relationship is addressed.

Combined modality treatment improves tumor control and overall survival in patients with early stage Hodgkin's lymphoma: a systematic review

Combined modality treatment (CMT) of chemotherapy followed by localized radiotherapy is standard treatment for patients with early stage Hodgkin's lymphoma. However, the role of radiotherapy has been questioned recently and some clinical study groups advocate chemotherapy only for this indication. We thus performed a systematic review with meta-analysis of randomized controlled trials comparing chemotherapy alone with CMT in patients with early stage Hodgkin's lymphoma with respect to response rate, tumor control and overall survival (OS). We searched Medline, EMBASE and the Cochrane Library as well as conference proceedings from January 1980 to February 2009 for randomized controlled trials comparing chemotherapy alone versus the same chemotherapy regimen plus radiotherapy. Progression free survival and similar outcomes were analyzed together as tumor control. Effect measures used were hazard ratios for OS and tumor control as well as relative risks for complete response (CR). Meta-analyses were performed using RevMan5. Five randomized controlled trials involving 1,245 patients were included. The hazard ratio (HR) was 0.41 (95% confidence interval (CI) 0.25 to 0.66) for tumor control and 0.40 (95% CI 0.27 to 0.59) for OS for patients receiving CMT compared to chemotherapy alone. CR rates were similar between treatment groups. In sensitivity analyses another 6 trials were included that did not fulfill the inclusion criteria of our protocol but were considered relevant to the topic. These trials underlined the results of the main analysis. In conclusion, adding radiotherapy to chemotherapy improves tumor control and OS in patients with early stage Hodgkin's lymphoma.

TRAIL signaling is mediated by DR4 in pancreatic tumor cells despite the expression of functional DR5

Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) and agonistic anti-DR4/TRAIL-R1 and anti-DR5/TRAIL-R2 antibodies are currently under clinical investigation for treatment of different malignancies. TRAIL activates DR4 and DR5 and thereby triggers apoptotic and non-apoptotic signaling pathways, but possible different roles of DR4 or DR5 in these responses has poorly been addressed so far. In the present work, we analyzed cell viability, DISC formation as well as IL-8 and NF-kappaB activation side by side in responses to TRAIL and agonistic antibodies against DR4 (mapatumumab) and against DR5 (lexatumumab) in pancreatic ductal adenocarcinoma cells. We found that all three reagents are able to activate cell death and pro-inflammatory signaling. Death-inducing signaling complex (DISC) analysis revealed that mapatumumab and lexatumumab induce formation of homocomplexes of either DR4 or DR5, whereas TRAIL additionally stimulated the formation of heterocomplexes of both receptors. Notably, blocking of receptors using DR4- and DR5-specific Fab fragments indicated that TRAIL exerted its function predominantly via DR4. Interestingly, inhibition of PKC by Goe6983 enabled DR5 to trigger apoptotic signaling in response to TRAIL and also strongly enhanced lexatumumab-mediated cell death. Our results suggest the existence of mechanisms that silence DR5 for TRAIL- but not for agonistic-antibody treatment.

The lectin-like domain of tumor necrosis factor improves lung function after rat lung transplantation--potential role for a reduction in reactive oxygen species generation

To test the hypothesis that the lectin-like domain of tumor necrosis factor, mimicked by the TIP peptide, can improve lung function after unilateral orthotopic lung isotransplantation. Because of a lack of a specific treatment for ischemia reperfusion-mediated lung injury, accompanied by a disrupted barrier integrity and a dysfunctional alveolar liquid clearance, alternative therapies restoring these parameters after lung transplantation are required.

Atlas-Based Segmentation of Brain Tumor Images Using a Markov Random Field-Based Tumor Growth Model and Non-Rigid Registration

We propose a new and clinically oriented approach to perform atlas-based segmentation of brain tumor images. A mesh-free method is used to model tumor-induced soft tissue deformations in a healthy brain atlas image with subsequent registration of the modified atlas to a pathologic patient image. The atlas is seeded with a tumor position prior and tumor growth simulating the tumor mass effect is performed with the aim of improving the registration accuracy in case of patients with space-occupying lesions. We perform tests on 2D axial slices of five different patient data sets and show that the approach gives good results for the segmentation of white matter, grey matter, cerebrospinal fluid and the tumor.

Biomechanical model of tumor growth: application to the European ContraCancrum project

This abstract presents the biomechanical model that is used in the European ContraCancrum project, aiming at simulating tumor evolution in the brain and lung. The construction of the finite element model as well as a simulation of tumor growth are shown. The construction of the mesh is fully automatic and is therefore compatible with a clinical application. This biomechanical model will be later combined to a cellular level simulator also developed in the project.

Absence of somatostatin SST(2) receptor internalization in vivo after intravenous SOM230 application in the AR42J animal tumor model

Among clinically relevant somatostatin functions, agonist-induced somatostatin receptor subtype 2 (sst(2)) internalization is a potent mechanism for tumor targeting with sst(2) affine radioligands such as octreotide. Since, as opposed to octreotide, the second generation multi-somatostatin analog SOM230 (pasireotide) exhibits strong functional selectivity, it appeared of interest to evaluate its ability to affect sst(2) internalization in vivo. Rats bearing AR42J tumors endogenously expressing somatostatin sst(2) receptors were injected intravenously with SOM230 or with the [Tyr(3), Thr(8)]-octreotide (TATE) analog; they were euthanized at various time points; tumors and pancreas were analyzed by immunohistochemistry for the cellular localization of somatostatin sst(2) receptors. SOM230-induced sst(2) internalization was also evaluated in vitro by immunofluorescence microscopy in AR42J cells. At difference to the efficient in vivo sst(2) internalization triggered by intravenous [Tyr(3), Thr(8)]-octreotide, intravenous SOM230 did not elicit sst(2) internalization: immunohistochemically stained sst(2) in AR42J tumor cells and pancreatic cells were detectable at the cell surface at 2.5min, 10min, 1h, 6h, or 24h after SOM230 injection while sst(2) were found intracellularly after [Tyr(3), Thr(8)]-octreotide injection. The inability of stimulating sst(2) internalization by SOM230 was confirmed in vitro in AR42J cells by immunofluorescence microscopy. Furthermore, SOM230 was unable to antagonize agonist-induced sst(2) internalization, neither in vivo, nor in vitro. Therefore, SOM230 does not induce sst(2) internalization in vivo or in vitro in AR42J cells and pancreas, at difference to octreotide derivatives with comparable sst(2) binding affinities. These characteristics may point towards different tumor targeting but also to different desensitization properties of clinically applied SOM230.

Role of somatostatins in gastroenteropancreatic neuroendocrine tumor development and therapy

The incidence and prevalence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) have increased in the past 20 years. GEP-NETs are heterogeneous tumors, in terms of clinical and biological features, that originate from the pancreas or the intestinal tract. Some GEP-NETs grow very slowly, some grow rapidly and do not cause symptoms, and others cause hormone hypersecretion and associated symptoms. Most GEP-NETs overexpress receptors for somatostatins. Somatostatins inhibit the release of many hormones and other secretory proteins; their effects are mediated by G protein-coupled receptors that are expressed in a tissue-specific manner. Most GEP-NETs overexpress the somatostatin receptor SSTR2; somatostatin analogues are the best therapeutic option for functional neuroendocrine tumors because they reduce hormone-related symptoms and also have antitumor effects. Long-acting formulations of somatostatin analogues stabilize tumor growth over long periods. The development of radioactive analogues for imaging and peptide receptor radiotherapy has improved the management of GEP-NETs. Peptide receptor radiotherapy has significant antitumor effects, increasing overall survival times of patients with tumors that express a high density of SSTRs, particularly SSTR2 and SSTR5. The multi-receptor somatostatin analogue SOM230 (pasireotide) and chimeric molecules that bind SSTR2 and the dopamine receptor D2 are also being developed to treat patients with GEP-NETs. Combinations of radioactive labeled and unlabeled somatostatin analogues and therapeutics that inhibit other signaling pathways, such as mammalian target of rapamycin (mTOR) and vascular endothelial growth factor, might be the most effective therapeutics for GEP-NETs.

Tumor necrosis factor sensitizes primary murine hepatocytes to Fas/CD95-induced apoptosis in a Bim- and Bid-dependent manner

Fas/CD95 is a critical mediator of cell death in many chronic and acute liver diseases and induces apoptosis in primary hepatocytes in vitro. In contrast, the proinflammatory cytokine tumor necrosis factor α (TNFα) fails to provoke cell death in isolated hepatocytes but has been implicated in hepatocyte apoptosis during liver diseases associated with chronic inflammation. Here we report that TNFα sensitizes primary murine hepatocytes cultured on collagen to Fas ligand (FasL)-induced apoptosis. This synergism is time-dependent and is specifically mediated by TNFα. Fas itself is essential for the sensitization, but neither Fas up-regulation nor endogenous FasL is responsible for this effect. Although FasL is shown to induce Bid-independent apoptosis in hepatocytes cultured on collagen, the sensitizing effect of TNFα is clearly dependent on Bid. Moreover, both c-Jun N-terminal kinase activation and Bim, another B cell lymphoma 2 homology domain 3 (BH3)-only protein, are crucial mediators of TNFα-induced apoptosis sensitization. Bim and Bid activate the mitochondrial amplification loop and induce cytochrome c release, a hallmark of type II apoptosis. The mechanism of TNFα-induced sensitization is supported by a mathematical model that correctly reproduces the biological findings. Finally, our results are physiologically relevant because TNFα also induces sensitivity to agonistic anti-Fas-induced liver damage. CONCLUSION: Our data suggest that TNFα can cooperate with FasL to induce hepatocyte apoptosis by activating the BH3-only proteins Bim and Bid.

Intrapancreatic Accessory Spleen Misdiagnosed as a Nonsecreting Endocrine Tumor: Case Report and Review of the Literature

In a large series of nonselected autopsy investigations an accessory spleen was found in 10-30%. The second most common site is the pancreatic tail (17%). We report a case of intrapancreatic accessory spleen misdiagnosed as a nonsecreting neuroendocrine tumor of the pancreas. Nuclear scintigraphy may provide the definitive diagnosis of an intrapancreatic spleen and therefore prevent patients from unnecessary major surgery.

BTLA mediates inhibition of human tumor-specific CD8+ T cells that can be partially reversed by vaccination

The function of antigen-specific CD8+ T cells, which may protect against both infectious and malignant diseases, can be impaired by ligation of their inhibitory receptors, which include CTL-associated protein 4 (CTLA-4) and programmed cell death 1 (PD-1). Recently, B and T lymphocyte attenuator (BTLA) was identified as a novel inhibitory receptor with structural and functional similarities to CTLA-4 and PD-1. BTLA triggering leads to decreased antimicrobial and autoimmune T cell responses in mice, but its functions in humans are largely unknown. Here we have demonstrated that as human viral antigen-specific CD8+ T cells differentiated from naive to effector cells, their surface expression of BTLA was gradually downregulated. In marked contrast, human melanoma tumor antigen-specific effector CD8+ T cells persistently expressed high levels of BTLA in vivo and remained susceptible to functional inhibition by its ligand herpes virus entry mediator (HVEM). Such persistence of BTLA expression was also found in tumor antigen-specific CD8+ T cells from melanoma patients with spontaneous antitumor immune responses and after conventional peptide vaccination. Remarkably, addition of CpG oligodeoxynucleotides to the vaccine formulation led to progressive downregulation of BTLA in vivo and consequent resistance to BTLA-HVEM-mediated inhibition. Thus, BTLA activation inhibits the function of human CD8+ cancer-specific T cells, and appropriate immunotherapy may partially overcome this inhibition.

One-Step (18)F-Labeling of Carbohydrate-Conjugated Octreotate-Derivatives Containing a Silicon-Fluoride-Acceptor (SiFA): In Vitro and in Vivo Evaluation as Tumor Imaging Agents for Positron Emission Tomography (PET)

The synthesis, radiolabeling, and initial evaluation of new silicon-fluoride acceptor (SiFA) derivatized octreotate derivatives is reported. So far, the main drawback of the SiFA technology for the synthesis of PET-radiotracers is the high lipophilicity of the resulting radiopharmaceutical. Consequently, we synthesized new SiFA-octreotate analogues derivatized with Fmoc-NH-PEG-COOH, Fmoc-Asn(Ac?AcNH-?-Glc)-OH, and SiFA-aldehyde (SIFA-A). The substances could be labeled in high yields (38 ± 4%) and specific activities between 29 and 56 GBq/?mol in short synthesis times of less than 30 min (e.o.b.). The in vitro evaluation of the synthesized conjugates displayed a sst2 receptor affinity (IC?? = 3.3 ± 0.3 nM) comparable to that of somatostatin-28. As a measure of lipophilicity of the conjugates, the log P(ow) was determined and found to be 0.96 for SiFA-Asn(AcNH-?-Glc)-PEG-Tyr³-octreotate and 1.23 for SiFA-Asn(AcNH-?-Glc)-Tyr³-octreotate, which is considerably lower than for SiFA-Tyr³-octreotate (log P(ow) = 1.59). The initial in vivo evaluation of [¹?F]SiFA-Asn(AcNH-?-Glc)-PEG-Tyr³-octreotate revealed a significant uptake of radiotracer in the tumor tissue of AR42J tumor-bearing nude mice of 7.7% ID/g tissue weight. These results show that the high lipophilicity of the SiFA moiety can be compensated by applying hydrophilic moieties. Using this approach, a tumor-affine SiFA-containing peptide could successfully be used for receptor imaging for the first time in this proof of concept study.

Synergistic induction of cell death in liver tumor cells by TRAIL and chemotherapeutic drugs via the BH3-only proteins Bim and Bid

Although death receptors and chemotherapeutic drugs activate distinct apoptosis signaling cascades, crosstalk between the extrinsic and intrinsic apoptosis pathway has been recognized as an important amplification mechanism. Best known in this regard is the amplification of the Fas (CD95) signal in hepatocytes via caspase 8-mediated cleavage of Bid and activation of the mitochondrial apoptosis pathway. Recent evidence, however, indicates that activation of other BH3-only proteins may also be critical for the crosstalk between death receptors and mitochondrial triggers. In this study, we show that TNF-related apoptosis-inducing ligand (TRAIL) and chemotherapeutic drugs synergistically induce apoptosis in various transformed and untransformed liver-derived cell lines, as well as in primary human hepatocytes. Both, preincubation with TRAIL as well as chemotherapeutic drugs could sensitize cells for apoptosis induction by the other respective trigger. TRAIL induced a strong and long lasting activation of Jun kinase, and activation of the BH3-only protein Bim. Consequently, synergistic induction of apoptosis by TRAIL and chemotherapeutic drugs was dependent on Jun kinase activity, and expression of Bim and Bid. These findings confirm a previously defined role of TRAIL and Bim in the regulation of hepatocyte apoptosis, and demonstrate that the TRAIL-Jun kinase-Bim axis is a major and important apoptosis amplification pathway in primary hepatocytes and liver tumor cells.