An assessment of Canadian systems for triaging referred out genetic testing

The field of genetics is evolving rapidly, significantly expanding the number of clinically useful genetic tests. The cost of genetic testing has created an increasing burden on public health care budgets. In Canada, funding bodies have responded by developing independent systems. Key individuals in each province and territory participated in a semi-structured interview regarding the process in their jurisdiction to approve funding for referred out genetic testing and their decision-making criteria. Two themes were identified: the importance of clinical utility in decision-making and the utilization of genetic specialists as gate keepers. Allocation of a specific budget appears to be associated with some fiscal responsibility. Collaboration between provincial and territorial bodies may lead to a more unified approach across Canada.

Addressing perceptual insensitivity to facial affect in violent offenders: first evidence for the efficacy of a novel implicit training approach

BACKGROUND

Although impaired recognition of affective facial expressions has been conclusively linked to antisocial behavior, little is known about the modifiability of this deficit. This study investigated whether and under which circumstances the proposed perceptual insensitivity can be addressed with a brief implicit training approach.

METHOD

Facial affect recognition was assessed with an animated morph task, in which the participants (44 male incarcerated violent offenders and 43 matched controls) identified the onset of emotional expressions in animated morph clips that gradually changed from neutral to one of the six basic emotions. Half of the offenders were then implicitly trained to direct attention to salient face regions (attention training, AT) using a modified dot-probe task. The other half underwent the same protocol but the intensity level of the presented expressions was additionally manipulated over the course of training sessions (sensitivity to emotional expressions training, SEE training). Subsequently, participants were reassessed with the animated morph task.

RESULTS

Facial affect recognition was significantly impaired in violent offenders as compared with controls. Further, our results indicate that only the SEE training group exhibited a pronounced improvement in emotion recognition.

CONCLUSIONS

We demonstrated for the first time that perceptual insensitivity to facial affect can be addressed by an implicit training that directs attention to salient regions of a face and gradually decreases the intensity of the emotional expression. Future studies should focus on the potential of this intervention to effectively increase empathy and inhibit violent behavior in antisocial individuals.

3D high-content screening for the identification of compounds that target cells in dormant tumor spheroid regions

Cancer cells in poorly vascularized tumor regions need to adapt to an unfavorable metabolic microenvironment. As distance from supplying blood vessels increases, oxygen and nutrient concentrations decrease and cancer cells react by stopping cell cycle progression and becoming dormant. As cytostatic drugs mainly target proliferating cells, cancer cell dormancy is considered as a major resistance mechanism to this class of anti-cancer drugs. Therefore, substances that target cancer cells in poorly vascularized tumor regions have the potential to enhance cytostatic-based chemotherapy of solid tumors. With three-dimensional growth conditions, multicellular tumor spheroids (MCTS) reproduce several parameters of the tumor microenvironment, including oxygen and nutrient gradients as well as the development of dormant tumor regions. We here report the setup of a 3D cell culture compatible high-content screening system and the identification of nine substances from two commercially available drug libraries that specifically target cells in inner MCTS core regions, while cells in outer MCTS regions or in 2D cell culture remain unaffected. We elucidated the mode of action of the identified compounds as inhibitors of the respiratory chain and show that induction of cell death in inner MCTS core regions critically depends on extracellular glucose concentrations. Finally, combinational treatment with cytostatics showed increased induction of cell death in MCTS. The data presented here shows for the first time a high-content based screening setup on 3D tumor spheroids for the identification of substances that specifically induce cell death in inner tumor spheroid core regions. This validates the approach to use 3D cell culture screening systems to identify substances that would not be detectable by 2D based screening in otherwise similar culture conditions.

Abstract 4953: Stromal endosialin modulates the proinflammatory tumor microenvironment and is crucial for the growth of orthotopic pancreatic tumors

Endosialin (CD248), a transmembrane protein expressed in stromal fibroblasts and activated pericytes during embryonic development, is expressed in human carcinomas. Although its function is unknown, due to its highly specific expression pattern endosialin represents a promising anti-tumor target. To unravel the role of endosialin during tumor progression and metastasis, we employed systematic loss-of-function approaches in stromal fibroblasts in vitro as well as in subcutaneous and orthotopic tumors in vivo. These experiments revealed an important role of endosialin in regulating fibroblast proliferation and in orchestrating an inflammatory response by modulating the secretion of inflammatory cytokines (IL6) in stromal fibroblasts. The proinflammatory environment created by activated fibroblasts is thought to support tumor growth and metastasis in vivo. Experiments in endosialin-deficient mice confirmed an important role of endosialin in tumor progression in highly stroma-recruiting orthotopic pancreatic tumor models. Finally, lung metastases were dramatically decreased in endosialin-deficient mice supporting a role of a proinflammatory tumor stroma in tumor dissemination. Taken together, our experiments identify endosialin as an important modulator of stromal responses that are crucial for tumor progression and metastasis. Endosialin may therefore represent a novel target for development of anticancer therapies for solid tumors.

Citation Format: Sven Christian, Vijaysahankar Sivanandam, Michael Strerath, Heiner Apeler, Holger Hess-Stumpp, Hellmut G. Augustin. Stromal endosialin modulates the proinflammatory tumor microenvironment and is crucial for the growth of orthotopic pancreatic tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4953. doi:10.1158/1538-7445.AM2013-4953

A centralized approach to out-of-province genetic testing leads to cost savings: the Alberta experience

The Genetic Resource Center (GRC) is a centralized process for requesting genetic testing that is not available within the province (Alberta, Canada). In order to assess potential cost savings associated with this process, all applications received by the GRC in 2010 were reviewed, and cost savings were recorded for statistical analysis. Seven areas of cost savings were identified: (i) negotiated pricing, (ii) laboratory selection, (iii) testing setup in-province, (iv) duplicate testing, (v) inappropriate testing, (vi) sequential testing and (vii) testing offered within the province.The total test cost of the 615 applications submitted in 2010 without the GRC process would have been $766,783 (Canadian dollars). A total cost savings of $112,201 was achieved through the GRC, which represents 15% of the total cost of requested testing ($112,201/$766,783). This is the first study to examine areas of cost savings for genetic testing sent out-of-province. The greatest cost savings resulted from the areas of laboratory selection and negotiated pricing. A centralized process to manage out-of-province genetic test requests results in consistency in testing and significant cost savings.

Quantum dot-conjugated anti-GRP78 scFv inhibits cancer growth in mice

Semiconductor quantum dots (Qdots) have recently been shown to offer significant advantages over conventional fluorescent probes to image and study biological processes. The stability and low toxicity of QDs are well suited for biological applications. Despite this, the potential of Qdots remains limited owing to the inefficiency of existing delivery methods. By conjugating Qdots with small antibody fragments targeting membrane-bound proteins, such as GRP78, we demonstrate here that the Quantum dot- Anti-GRP78 scFv (Qdot-GRP78) retains its immunospecificity and its distribution can be monitored by visualization of multi-color fluorescence imaging both in vitro and in vivo. Moreover we demonstrate here for the first time that Qdot-GRP78 scFv bioconjugates can be efficiently internalized by cancer cells, thus upregulate phophosphate-AKT-ser473 and possess biological anti-tumour activity as shown by inhibition of breast cancer growth in a xenograft model. This suggests that nanocarrier-conjugated scFvs can be used as a therapeutic antibody for cancer treatment.

Abstract 539: Endosialin (TEM1) is a tumor stroma marker and receptor for the metastasis-related Mac-2 binding protein

Endosialin is a heavily sialylated C-type lectin. It is a single transmembrane molecule that was identified by two independent studies as an angiogenic endothelial specific marker. However, recent high resolution confocal expression studies by our and other laboratories have revealed that Endosialin is not expressed by endothelial cells but instead by angiogenic blood vessel associated pericytes. Detailed tissue array-based expression profiling validated Endosialin as an oncofetal gene product of the mesenchymal lineage that is hardly detectable in normal tissues but abundantly expressed by tumor vessel-associated pericytes and tumor stromal fibroblasts (myofibroblasts). As such, Endosialin was not just identified as a marker of activated pericytes but based on its exclusive tumor-associated expression also as a novel therapeutic tumor stroma target. Cytokine induction experiments identified Endosialin as a major downstream target of TGFß stimulation. Cellular siRNA-based loss-of-function experiments unravelled a role of Endosialin in the regulation of mesenchymal cell adhesion, migration and proliferation. These findings prompted experiments aimed at identifying the extracellular ligand of Endosialin. Using Endosialin-Fc as an affinity probe, the metastasis associated molecule Mac-2BP/90K was identified as high affinity extracellular Endosialin ligand. As Endosialin, Mac-2BP/90K displays an exclusive tumor progression associated expression pattern. However, in contrast to the stromal expression of Endosialin, Mac-2BP/90K is strictly expressed by the tumor cell compartment. The mutually exclusive expression pattern suggests a repulsive interaction between Endosialin and Mac-2BP/90K which was confirmed in cellular experiments. Ongoing experiments are aimed at mechanistically studying the role of the Endosialin - Mac-2BP/90K interaction in controlling the crosstalk between the tumor cell and the stromal cell compartments during tumor progression and metastasis.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 539.

Cell surface nucleolin antagonist causes endothelial cell apoptosis and normalization of tumor vasculature

Nucleolin is specifically transported to the surface of proliferating endothelial cells in vitro and in vivo. In contrast to its well defined functions in the nucleus and cytoplasm, the function of cell surface nucleolin is poorly defined. We have previously identified the nucleolin-binding antibody NCL3 that specifically binds to cell surface nucleolin on angiogenic blood vessels in vivo and is internalized into the cell. Here, we show that NCL3 inhibits endothelial tube formation in vitro as well as angiogenesis in the matrigel plaque assay and subcutaneous tumor models in vivo. Intriguingly, the specific targeting of proliferating endothelial cells by NCL3 in subcutaneous tumor models leads to the normalization of the tumor vasculature and as a result to an increase in tumor oxygenation. Treatment of endothelial cells with anti-nucleolin antibody NCL3 leads to a decrease of mRNA levels of the anti-apoptotic molecule Bcl-2 and as a consequence induces endothelial cell apoptosis as evidenced by PARP cleavage. These data reveal a novel mode of action for anti-angiogenic therapy and identify cell surface nucleolin as a novel target for combinatorial chemotherapy.

Angiopoietin-2 levels are associated with disease progression in metastatic malignant melanoma

PURPOSE

The blood vessel-destabilizing Tie2 ligand angiopoietin-2 (Ang-2) acts in concert with the vascular endothelial growth factor/vascular endothelial growth factor receptor system to control vessel assembly during tumor progression. We hypothesized that circulating soluble Ang-2 (sAng-2) may be involved in melanoma progression.

EXPERIMENTAL DESIGN

Serum samples (n=98) from melanoma patients (American Joint Committee on Cancer stages I-IV), biopsies of corresponding patients, and human melanoma cell lines were analyzed for expression of Ang-2 and S100beta. Multiple sera of a subcohort of 33 patients were tested during progression from stage III to IV. Small interfering RNA-based loss-of-function experiments were done to assess effects of Ang-2 on melanoma cells.

RESULTS

Circulating levels of sAng-2 correlate with tumor progression in melanoma patients (P<0.0001) and patient survival (P=0.007). Analysis of serum samples during the transition from stage III to IV identified an increase of sAng-2 up to 400%. Comparative analyses revealed a 56% superiority of sAng-2 as predictive marker over the established marker S100beta. Immunohistochemistry and reverse transcription-PCR confirmed the prominent expression of Ang-2 by tumor-associated endothelial cells but identified Ang-2 also as a secreted product of melanoma cells themselves. Corresponding cellular experiments revealed that human melanoma-isolated tumor cells were Tie2 positive and that Ang-2 acted as an autocrine regulator of melanoma cell migration and invasion.

CONCLUSIONS

The experiments establish sAng-2 as a biomarker of melanoma progression and metastasis correlating with tumor load and overall survival. The identification of an autocrine angiopoietin/Tie loop controlling melanoma migration and invasion warrants further functional experiments and validate the angiopoietin/Tie system as a promising therapeutic target for human melanomas.

Tumor stroma marker endosialin (Tem1) is a binding partner of metastasis-related protein Mac-2 BP/90K

Tumor development involves complex bidirectional interactions between tumor cells and host stromal cells. Endosialin (Tem1) has been identified as a highly O-glycosylated transmembrane glycoprotein, which is specifically expressed by tumor vessel-associated pericytes and stromal fibroblasts of a wide range of human tumors. Recent experiments in endosialin-deficient mice have unraveled a critical role of endosialin in site-specific tumor progression and metastasis. To molecularly understand the mechanisms of endosialin function, we aimed to identify extracellular endosialin ligands and identified Mac-2 BP/90K as a specific interaction partner. Detailed biochemical analyses identified a C-terminal fragment of Mac-2 BP/90K, which was shown to contain binding sites for galectin-3, and collagens as the structures responsible for endosialin binding. Subsequent expression analysis of Mac-2 BP/90K in vivo revealed weak or no expression in most normal tissues and strong up-regulation in tumor cells of human neoplastic tissues. Intriguingly, the expression patterns of Mac-2 BP/90K and endosialin were mutually exclusive in all human tissues. Correspondingly, loss-of-function adhesion experiments of Mac-2 BP/90K-expressing tumor cells on endosialin-expressing fibroblasts revealed a repulsive outcome of the Mac-2 BP/90K interaction. Taken together, the experiments identify a novel repulsive interaction between endosialin on stromal fibroblasts and Mac-2 BP/90K on tumor cells.

Endosialin (Tem1) is a marker of tumor-associated myofibroblasts and tumor vessel-associated mural cells

Endosialin (Tem1) has been identified by two independent experimental approaches as an antigen of tumor-associated endothelial cells, and it has been claimed to be the most abundantly expressed tumor endothelial antigen, making it a prime candidate for vascular targeting purposes. Recent experiments have challenged the endothelial expression of endosialin and suggested an expression by activated fibroblasts and pericytes. Thus, clarification of the controversial cellular expression of endosialin is critically important for an understanding of its role during tumor progression and its validation as a potential therapeutic target. We have therefore performed extensive expression profiling analyses of endosialin. The experiments unambiguously demonstrate that endosialin is expressed by tumor-associated myofibroblasts and mural cells and not by endothelial cells. Endosialin expression is barely detectable in normal human tissues with moderate expression only detectable in the stroma of the colon and the prostate. Corresponding cellular experiments confirmed endosialin expression by mesenchymal cells and indicated that it may in fact be a marker of mesenchymal stem cells. Silencing endosialin expression in fibroblasts strongly inhibited migration and proliferation. Collectively, the experiments validate endosialin as a marker of tumor-associated myofibroblasts and tumor vessel-associated mural cells. The data warrant further functional analysis of endosialin during tumor progression and its exploitation as marker of tumor vessel-associated mural cells, expression of which may reflect the non-normalized phenotype of the tumor vasculature.

The sialomucin CD34 is a marker of lymphatic endothelial cells in human tumors

The mechanisms of lymphangiogenesis have been increasingly understood in recent years. Yet, the contribution of lymphangiogenesis versus lymphatic cooption in human tumors and the functionality of tumor lymphatics are still controversial. Furthermore, despite the identification of lymphatic endothelial cell (LEC) markers such as Prox1, podoplanin, LYVE-1, and VEGFR-3, no activation marker for tumor-associated LECs has been identified. Applying double-staining techniques with established LEC markers, we have screened endothelial cell differentiation antigens for their expression in LECs. These experiments identified the sialomucin CD34 as being exclusively expressed by LECs in human tumors but not in corresponding normal tissues. CD34 is expressed by LYVE-1(+)/podoplanin(+)/Prox1(+) tumor-associated LECs in colon, breast, lung, and skin tumors. More than 60% of analyzed tumors contained detectable intratumoral lymphatics. Of these, more than 80% showed complete co-localization of CD34 with LEC markers. In contrast, LECs in all analyzed normal organs did not express CD34. Corresponding analyses of experimental tumors revealed that mouse tumor-associated LECs do not express CD34. Taken together, these experiments identify CD34 as the first differentially expressed LEC antigen that is selectively expressed by tumor-associated LECs. The data warrant further exploration of CD34 in tumor-associated LECs as a prognostic tumor marker.

Nucleolin expressed at the cell surface is a marker of endothelial cells in angiogenic blood vessels

A tumor-homing peptide, F3, selectively binds to endothelial cells in tumor blood vessels and to tumor cells. Here, we show that the cell surface molecule recognized by F3 is nucleolin. Nucleolin specifically bound to an F3 peptide affinity matrix from extracts of cultured breast carcinoma cells. Antibodies and cell surface biotin labeling revealed nucleolin at the surface of actively growing cells, and these cells bound and internalized fluorescein-conjugated F3 peptide, transporting it into the nucleus. In contrast, nucleolin was exclusively nuclear in serum-starved cells, and F3 did not bind to these cells. The binding and subsequent internalization of F3 were blocked by an antinucleolin antibody. Like the F3 peptide, intravenously injected antinucleolin antibodies selectively accumulated in tumor vessels and in angiogenic vessels of implanted "matrigel" plugs. These results show that cell surface nucleolin is a specific marker of angiogenic endothelial cells within the vasculature. It may be a useful target molecule for diagnostic tests and drug delivery applications.

[The influence of daily psychosocial stressors and associated emotions on the dynamic course of urine cortisol and urine neopterin in systemic lupus erythematosus: Experience taken from two "integrative single-case studies"]

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by flare-ups, the cause of which is unknown. According to new stress concepts, two "integrative single-case studies" have been conducted in order to gather evidence about whether daily stressful incidents and associated emotions interfere with the dynamics of urine cortisol and urine neopterin in SLE. Patients under study collected their urine at home, for a period of at least 50 days, on a daily basis, divided into day and night urine. Additionally, patients filled out questionnaires twice a day to determine their emotional state, life style and disease activity. Each week, patients were examined clinically and interviewed to identify the past week's stressors using the Incidents and Hassles Inventory (IHI, Brown and Harris). Statistical analysis of the serial data was performed using time-series analysis according to Box and Jenkins. In both "integrative single-case studies" we were able to demonstrate that stressful incidents predicted an increase in urine neopterin 36 hours (Case 1) to 60 hours (Case 2) later (p < 0.05). Additionally, in Case 1 the neopterin levels were highly associated with stress resulting from the weekly examinations and interviews. Furthermore, in Case 2 it turned out that depending on their predictability stressful incidents were preceded by a decrease in urine cortisol 12 hours earlier or were followed by a decrease in urine cortisol 36 hours later. And finally, emotional irritation was highly correlated with the course of urine-neopterin. In Case 2 irritation led to an increase in urine neopterin 84 hours later. There were no clinical signs of SLE during both prospective studies. In conclusion, our results validate the idea of "integrative single-case studies" as a new "bio-psycho-social" approach in psychoneuroimmunology. Further studies with SLE patients as well as with healthy probands will be necessary in order to both strengthen and generalize these results.

Molecular cloning and characterization of EndoGlyx-1, an EMILIN-like multisubunit glycoprotein of vascular endothelium

EndoGlyx-1, the antigen identified with the monoclonal antibody H572, is a pan-endothelial human cell surface glycoprotein complex composed of four different disulfide-bonded protein species with an apparent molecular mass of approximately 500 kDa. Here, we report the purification and peptide analysis of two EndoGlyx-1 subunits, p125 and p140, and the identification of a common, full-length cDNA with an open reading frame of 2847 base pairs. The EndoGlyx-1 cDNA encodes a protein of 949 amino acids with a predicted molecular mass of 105 kDa, found as an entry for an unnamed protein with unknown function in public data bases. A short sequence tag matching the cDNA of this gene was independently discovered by serial analysis of gene expression profiling as a pan-endothelial marker, PEM87. Bioinformatic evaluation classifies EndoGlyx-1 as an EMILIN-like protein composed of a signal sequence, an N-terminal EMI domain, and a C-terminal C1q-like domain, separated from each other by a central coiled-coil-rich region. Biochemical and carbohydrate analysis revealed that p125, p140, and the two additional EndoGlyx-1 subunits, p110 and p200, are exposed on the cell surface. The three smaller subunits show a similar pattern of N-linked and O-linked carbohydrates, as shown by enzyme digestion. Because the two globular domains of EndoGlyx-1 p125/p140 show structural features shared by EMILIN-1 and Multimerin, two oligomerizing glycoproteins implicated in cell-matrix adhesion and hemostasis, it will be of interest to explore similar functions for EndoGlyx-1 in human vascular endothelium.

Molecular cloning and characterization of endosialin, a C-type lectin-like cell surface receptor of tumor endothelium

Endosialin, the antigen identified with monoclonal antibody FB5, is a highly restricted 165-kDa cell surface glycoprotein expressed by tumor blood vessel endothelium in a broad range of human cancers but not detected in blood vessels or other cell types in many normal tissues. Functional analysis of endosialin has been hampered by a lack of information about its molecular structure. In this study, we describe the purification and partial amino acid sequencing of endosialin, leading to the cloning of a full-length cDNA with an open reading frame of 2274 base pairs. The endosialin cDNA encodes a type I membrane protein of 757 amino acids with a predicted molecular mass of 80.9 kDa. The sequence matches with an expressed sequence tag of unknown function in public data bases, named TEM1, which was independently linked to tumor endothelium by serial analysis of gene expression profiling. Bioinformatic evaluation classifies endosialin as a C-type lectin-like protein, composed of a signal leader peptide, five globular extracellular domains (including a C-type lectin domain, one domain with similarity to the Sushi/ccp/scr pattern, and three EGF repeats), followed by a mucin-like region, a transmembrane segment, and a short cytoplasmic tail. Carbohydrate analysis shows that the endosialin core protein carries abundantly sialylated, O-linked oligosaccharides and is sensitive to O-sialoglycoprotein endopeptidase, placing it in the group of sialomucin-like molecules. The N-terminal 360 amino acids of endosialin show homology to thrombomodulin, a receptor involved in regulating blood coagulation, and to complement receptor C1qRp. This structural kinship may indicate a function for endosialin as a tumor endothelial receptor for as yet unknown ligands, a notion now amenable to molecular investigation.

Characterization of antibody response to porcine reproductive and respiratory syndrome virus ORF5 product following infection and evaluation of its diagnostic use in pigs

The sensitivity and specificity of recombinant open reading frame 5 products used in the Western blotting assay for confirmation of porcine reproductive and respiratory syndrome virus (PRRSV) serologic status were evaluated. The recombinant antigen-based assays were specifically compared with a commercial enzyme-linked immunosorbent assay (ELISA) for PRRSV antibodies using 1) PRRSV antibody-negative reference sera (n = 30), 2) naturally infected pig sera (n = 40), 3) sequential sera obtained from 24 experimentally infected pigs, and 4) sera submitted to 3 state diagnostic laboratories (n = 200). The recombinant antigen assay yielded an average increased sensitivity of 10% over the commercial PRRSV ELISA. The negative controls (group 1 sera) showed no difference between the 2 assays. This comparison confirmed that the recombinant antigen-specific assay was more sensitive than the commercial ELISA and is well suited for routine confirmation of the presence of PRRSV antibodies.