Influence of age on the relation between body position and noninvasively acquired intracranial pulse waves

The capacitive measurement of the head's dielectric properties has been recently proposed as a noninvasive method for deriving surrogates of craniospinal compliance (CC), a parameter used in the evaluation of space-occupying neurological disorders. With the higher prevalence of such disorders in the older compared to the younger population, data on the head's dielectric properties of older healthy individuals would be of particularly high value before assessing pathologic changes. However, so far only measurements on young volunteers (< 30 years) were reported. In the present study, we have investigated the capacitively obtained electric signal known as W in older healthy individuals. Thirteen healthy subjects aged > 60 years were included in the study. W was acquired in the resting state (supine horizontal position), and during head-up and head-down tilting. AMP, the peak-to-valley amplitude of W related to cardiac action, was extracted from W. AMP was higher in this older cohort compared to the previously investigated younger one (0°: 5965 ± 1677 arbitrary units (au)). During head-up tilting, AMP decreased (+ 60°: 4446 ± 1620 au, P < 0.001), whereas it increased during head-down tilting (- 30°: 7600 ± 2123 au, P < 0.001), as also observed in the younger cohort. Our observation that AMP, a metric potentially reflective of CC, is higher in the older compared to the younger cohort aligns with the expected decrease of CC with age. Furthermore, the robustness of AMP is reinforced by the consistent relative changes observed during tilt testing in both cohorts.

Prevalence of pain and its association with symptoms of post-traumatic stress disorder, depression, anxiety and distress in 846 cancer patients: A cross sectional study

Objective

Pain depicts a severe physical symptom but its relationship to mental health problems is not well studied in cancer patients. The aim of this study was to investigate the prevalence of pain and its correlation with symptoms of post‐traumatic stress disorder (PTSD), depression, anxiety and psychological distress in a large sample of cancer patients.

Methods

From 2010 to 2019, cancer patients who received outpatient treatment at the Medical University of Vienna were assessed with the Post‐Traumatic Symptom Scale (PTSS‐10) and the Hospital Anxiety and Depression Scales. A visual analogue scale was used to assess pain perception. For statistical analysis, linear regression models were applied to log‐transformed data.

Results

Of the 846 cancer patients included in the study, 63.5% experienced pain (mild 43.5%, moderate 13.6%, severe 6.4%). About a third (31.2%) of the total sample presented with significant PTSD symptoms. Significant symptoms of depression, anxiety and distress were present in 13.9%, 15.1% and 25.3%, respectively. Women more often reported symptoms of PTSD, anxiety and distress. Pain scores were significantly related to symptoms of PTSD, depression and psychological distress (all with p < .001), but not to anxiety.

Conclusions

Results show a high prevalence of experienced pain and indicate a clear association of elevated pain levels with psychiatric symptoms in oncological patients in a large Austrian sample. In order to decrease experienced pain and to enable better treatment of mental health problems in cancer patients, diagnostic procedures and interventions based on a biopsychosocial model need to be intensified.

Abstract PD1-12: Omics profiling of CDK4/6 inhibitors reveals functionally important secondary targets of abemaciclib

The recent introduction of small molecule inhibitors of cyclin-dependent kinases (CDK) 4/6 to the clinic has improved the treatment of hormone receptor positive breast cancer, and shown promise in other malignancies. The three clinically used CDK4/6 inhibitors, palbociclib, ribociclib, and abemaciclib, are reported to be broadly similar although recent data suggest that abemaciclib has distinct single-agent activity in patients and a unique adverse effects profile. Key questions are: How do these drugs differ at the molecular level? Should such differences inform their use in the clinic? Can these three agents be used interchangeably or should patient stratification differ between them? We use molecular and functional profiling by mRNA sequencing, mass spectrometry-based proteomics, and GR-based dose-response assays to obtain complementary views of the mechanisms of action of CDK4/6 inhibitors. We show that abemaciclib, but not ribociclib or palbociclib, is a potent inhibitor of kinases other than CDK4/6, including CDK1/Cyclin B, which appears to cause arrest in the G2 phase of the cell cycle, and CDK2/Cyclin E/A, which is implicated in resistance to palbociclib. We show that inhibition of these additional targets is accessible in a xenograft model. Whereas ribociclib and palbociclib induce cytostasis, and cells adapt to these drugs within 2-3 days of exposure, abemaciclib induces cell death and durably blocks cell proliferation. Abemaciclib is active even in retinoblastoma protein (pRb)-deficient cells in which CDK4/6 inhibition by palbociclib or ribociclib is completely ineffective. The degree of polypharmacology of small molecule drugs is increasingly viewed as an important consideration in their design, with implications for efficacy, toxicity, and acquired resistance. In the case of CDK4/6 inhibitors, we propose that abemaciclib polypharmacology elicits unique molecular responses. More generally, we propose that multi-omic approaches are required to fully elucidate the spectrum of targets relevant to drug action in tumor cells. We expect such understanding to assist in stratifying patient populations and ordering sequential therapies when resistance arises.

Citation Format: Mills CE, Hafner M, Subramanian K, Chen C, Chung M, Boswell SA, Everley RA, Walmsley CS, Juric D, Sorger PK. Omics profiling of CDK4/6 inhibitors reveals functionally important secondary targets of abemaciclib [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-12.

Abstract GS3-05: Prospective optimization of estrogen receptor degradation yields ER ligands with variable capacities for ER transcriptional suppression

ER+ breast cancers can depend on ER signaling throughout disease progression, including after acquired resistance to existing endocrine agents, providing a rationale for further optimization and development of ER-targeting agents. Fulvestrant is unique amongst currently approved ER ligand therapeutics due to classification as a full ER antagonist, which is thought to be achieved through degradation of ER protein. However, the full clinical potential of fulvestrant is believed to be limited by poor bioavailability, spurring attempts to generate ligands capable of driving ER degradation but with improved drug-like properties.

Here, we evaluate three ER ligand clinical candidates that recently emerged from prospective optimization of ER degradation – GDC-0810, AZD9496 and GDC-0927 - and show that they display distinct mechanistic features. GDC-0810 and AZD9496 are more limited in their ER degradation capacity relative to GDC-0927 and fulvestrant, display evidence of weak transcriptional activation of ER in breast cancer cells (i.e. partial agonist activity), and do not achieve the same degree of in vitro anti-proliferative activity as GDC-0927 and fulvestrant. In the HCI-013 (ER.Y537S) and HCI-011 (ER.WT) ER+ patient-derived xenograft models, GDC-0927 drives greater transcriptional suppression of ER, and greater anti-tumor activity relative to GDC-0810.

We found that despite their full antagonist phenotype, GDC-0927 and fulvestrant promote association of ER with DNA, including at canonical ERE motifs, prior to ER degradation. Interestingly however, integration of ER ChIP-Seq and ATAC-Seq data revealed that ER complexed with fulvestrant or GDC-0927 fails to increase chromatin accessibility at DNA binding sites, in contrast to partial agonists which result in increased chromatin accessibility at ER binding sites. Thus, although ER contacts DNA when engaged with fulvestrant and GDC-0927, it is functionally inert. To further explore mechanistic features that might account for the differential activity of full antagonists and partial agonists that occurs prior to ER degradation, we used cell-based florescence recovery after photobleaching (FRAP) to measure the kinetics of ER diffusion within the nucleus. We demonstrate that while ER is generally highly mobile, including after engagement with GDC-0810 and AZD9496, GDC-0927 and fulvestrant immobilize intra-nuclear ER. A site saturating mutagenesis screen revealed a series of novel ER mutations that prevent ER immobilization by fulvestrant and GDC-0927. This class of “always mobile” ER variants promotes an antagonist-to-agonist transcriptional switch for fulvestrant and GDC-0927, and simultaneously prevents ER degradation by these molecules, implying that ER immobilization is a key functional determinant of robust transcriptional suppression.

We thus propose that ER degradation is not a driver of full ER antagonism, but rather a downstream consequence of ER immobilization, occurring after a suppressive phenotype has been established at chromatin. We additionally argue that evaluating the transcriptional output of candidate ER therapeutics, both pre-clinically and clinically, will be critical for the identification of ER ligands with best-in-class potential.

Citation Format: Metcalfe C, Zhou W, Guan J, Daemen A, Hafner M, Blake RA, Ingalla E, Young A, Oeh J, De Bruyn T, Ubhayakar S, Chen I, Giltnane JM, Li J, Wang X, Sampath D, Hager JH, Friedman LS. Prospective optimization of estrogen receptor degradation yields ER ligands with variable capacities for ER transcriptional suppression [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS3-05.

Abstract P2-07-03: Systematic characterization of kinase inhibitors reveals heterogeneity in responses by class and cell line

Several publications have addressed concerns surrounding drug response screens by pointing out sources of variability and by presenting recommendations for better experimental methods and more robust analytical approaches. In the presented profiling effort, we integrated the latest advances in drug response measurement and focused on data diversity and quality rather than on breadth. We selected 32 breast cancer cell lines with a strong bias towards triple negative lines as well as 4 cell lines established from relevant patient-derived xenografts. We evaluated a panel of clinically relevant kinase inhibitors using a microscopy-based dose response assay to measure drug potency, and to quantify drug efficacy in terms of growth inhibition (GR metrics) and cell death. The use of the GR metrics to quantify drug sensitivity enabled us to identify and study differences between cytostatic and cytotoxic responses. This systematic dose response dataset is complemented by measurements of baseline transcript expression levels by mRNAseq, quantification of absolute abundance of ˜12,000 proteins, and relative phosphoprotein levels by shotgun mass spectrometry across all cell lines. Additionally, the baseline activity of transcription factors and kinases were inferred from the mRNA (using VIPER) and phosphoprotein (using kinase enrichment analysis) data, respectively. The complementarity of these multi-omics data has allowed us to address questions about the landscape of breast cancer cell lines such as: Where do the patient-derived lines lay relative to the conventional cell lines? How consistent are the landscapes defined by each dataset? How does integration across datasets provide mechanistic insight into signaling pathways that are active in each cancer subtypes? The measured and inferred baseline data were used to build predictors of the observed drug responses with the goal of identifying the biological processes responsible for the differences in sensitivity across drugs and cell lines. Overall the dataset that has been collected is a valuable resource for understanding drug response in triple negative breast cancer, and the molecular mechanisms that influence it.

Citation Format: Mills CE, Subramanian K, Hafner M, Chung M, Boswell SA, Everley RA, Juric D, Sorger PK. Systematic characterization of kinase inhibitors reveals heterogeneity in responses by class and cell line [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-07-03.

Improving Fluid Management in Critical Care - Towards the ICU of the Future

BACKGROUND

The calculation of daily fluid balances is essential in perioperative and postoperative fluid management in order to prevent severe hypervolemia or hypovolemia in critically ill patients. In this context, modern health information technology has the potential to reduce the workload for health care professionals by not only automating data collection but also providing appropriate decision support.

OBJECTIVES

Within this work, current problems and barriers regarding fluid balancing in cardiac intensive care patients are outlined and improvement activities are specified.

METHODS

Literature research and qualitative interviews with health care professionals were conducted to assess the state-of-the-art technological setting within an intensive care unit.

RESULTS

An example case shows that interconnecting not only devices but also wards can facilitate daily clinical tasks.

CONCLUSION

Smart devices and decision support systems can improve fluid management. Several technologies, which today are sometimes still considered to be futuristic, are in fact not that far away or already available. However, they need proper implementation with respect to intensivists', nurses' and patients' needs.

Abstract P6-07-33: Metrics of drug sensitivity based on growth rate inhibition correct for the confounding effects of variable division rates

Drug sensitivity and resistance are conventionally quantified by IC50 or Emax values, but these metrics suffer from a fundamental flaw when applied to growing cells: they are highly sensitive to the number of divisions that take place over the course of a response assay. Division rate varies with cell line, experimental conditions, and genetic alterations. The dependency of IC50 and Emax on division rate creates artefactual correlations between genotype and drug sensitivity while obscuring important biological insights and interfering with biomarker discovery. In this work, we derive alternative drug response metrics that are insensitive to number of divisions occurring during the assay. These are based on estimating growth rate inhibition (GR) in the presence of a drug using endpoint or time-course assays. The latter provides a direct measure of phenomena such as adaptive drug resistance.

Using a simple model of drug response, we first show how GR50 and GRmax are superior to IC50 and Emax for assessing the effects of drugs in dividing cells. By expressing an oncogene in a transformed cell line, we illustrate how conventional metrics can lead to artefactual connections between mutations and drug sensitivity. We further validate the superiority of GR50 over IC50 values by reanalyzing a recently published large dataset of drug sensitivity and showing cases where difference in division rates is the only reason why IC50 values correlate with tissue type or genetic alterations. Using GR50 values prevents these artificial correlations and restores known connections between drug resistance and genomic markers. Finally, we show how GRmax values, which reflect efficacy, quantify differences in the phenotypic response and thus can be used to identify new biomarkers of sensitivity.

Adopting GR metrics requires only modest changes in experimental protocols. GR values and metrics can be evaluated using scripts are available on github (www.github.com/sorgerlab/gr50_tools) or using an interactive website: www.grcalculator.org. We expect GR metrics to improve the use of drugs to identify response biomarkers, study mechanisms of cell signaling and growth, and identify drugs effective on specific patient-derived tumor cells.Drug sensitivity and resistance are conventionally quantified by IC50 or Emax values, but these metrics suffer from a fundamental flaw when applied to growing cells: they are highly sensitive to the number of divisions that take place over the course of a response assay. Division rate varies with cell line, experimental conditions, and genetic alterations. The dependency of IC50 and Emax on division rate creates artefactual correlations between genotype and drug sensitivity while obscuring important biological insights and interfering with biomarker discovery. In this work, we derive alternative drug response metrics that are insensitive to number of divisions occurring during the assay. These are based on estimating growth rate inhibition (GR) in the presence of a drug using endpoint or time-course assays. The latter provides a direct measure of phenomena such as adaptive drug resistance.

Using a simple model of drug response, we first show how GR50 and GRmax are superior to IC50 and Emax for assessing the effects of drugs in dividing cells. By expressing an oncogene in a transformed cell line, we illustrate how conventional metrics can lead to artefactual connections between mutations and drug sensitivity. We further validate the superiority of GR50 over IC50 values by reanalyzing a recently published large dataset of drug sensitivity and showing cases where difference in division rates is the only reason why IC50 values correlate with tissue type or genetic alterations. Using GR50 values prevents these artificial correlations and restores known connections between drug resistance and genomic markers. Finally, we show how GRmax values, which reflect efficacy, quantify differences in the phenotypic response and thus can be used to identify new biomarkers of sensitivity.

Adopting GR metrics requires only modest changes in experimental protocols. GR values and metrics can be evaluated using scripts are available on github (www.github.com/sorgerlab/gr50_tools) or using an interactive website: www.grcalculator.org. We expect GR metrics to improve the use of drugs to identify response biomarkers, study mechanisms of cell signaling and growth, and identify drugs effective on specific patient-derived tumor cells.

Citation Format: Hafner M, Niepel M, Sorger PK. Metrics of drug sensitivity based on growth rate inhibition correct for the confounding effects of variable division rates [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-07-33.

New Processes for Freeze-Drying in Dual-Chamber Systems

Dual-chamber systems can offer self-administration and home care use for lyophilized biologics. Only a few products have been launched in dual-chamber systems so far-presumably due to dual-chamber systems' complex and costly drug product manufacturing process. Within this paper, two improved processes (both based on tray filling technology) for freeze-drying pharmaceuticals in dual-chamber systems are described. Challenges with regards to heat transfer were tackled by (1) performing the freeze-drying step in a needle-down orientation in combination with an aluminum block, or (2) freeze-drying the drug product "externally" in a metal cartridge with subsequent filling of the lyophilized cake into the dual-chamber system. Metal-mediated heat transfer was shown to be efficient in both cases and batch (unit-to-unit) homogeneity with regards to sublimation rate was increased. It was difficult to influence ice crystal size using different methods when in use with an aluminum block due to its heat capacity. Using such a metal carrier implies a large heat capacity leading to relatively small ice crystals. Compared to the established process, drying times were reduced by half using the new processes. The drying time was, however, longer for syringes compared to vials due to the syringe design (long and slim). The differences in drying times were less pronounced for aggressive drying cycles. The proposed processes may help to considerably decrease investment costs into dual-chamber system fill-finish equipment.

LAY ABSTRACT

Dual-chamber syringes offer self-administration and home care use for freeze-dried pharmaceuticals. Only a few products have been launched in dual-chamber syringes so far-presumably due to their complex and costly drug product manufacturing process. In this paper two improved processes for freeze-drying pharmaceuticals in dual-chamber syringes are described. The major challenge of freeze-drying is to transfer heat through a vacuum. The proposed processes cope with this challenge by (1) freeze-drying the drug product in the syringe in an orientation in which the product is closest to the heat source, or (2) freeze-drying the drug product outside the syringe in a metal tube. The latter requires filling the freeze-dried product subsequently into the dual-chamber syringe. Both processes were very efficient and promised to achieve similar freeze-drying conditions for all dual-chamber syringes within one production run. The proposed processes may help to considerably decrease investment costs into dual-chamber syringe fill-finish equipment.

Longitudinal evaluation of serum pancreatic enzymes and ultrasonographic findings in diabetic cats without clinically relevant pancreatitis at diagnosis

Background

Cats with diabetes mellitus can have subclinical pancreatitis but prospective studies to confirm this are lacking. Metabolic control of diabetic cats with pancreatitis is difficult.

Hypothesis

Subclinical pancreatitis occurs in diabetic cats at the time diabetes is diagnosed or might develop during the follow‐up period, hampering diabetic remission.

Animals

Thirty cats with newly diagnosed diabetes without clinical signs of pancreatitis on admission.

Methods

Prospective study. On admission and 2 and 6 months later, serum Spec fPL and DGGR‐lipase were measured and the pancreas underwent ultrasonographic examination. Pancreatitis was suspected if serum markers were increased or ≥2 ultrasonographic abnormalities were detected. Cats were treated with insulin glargine and diabetic remission was defined as euglycemia ≥4 weeks after discontinuation of insulin. Nonparametric statistical tests were used for analysis.

Results

Subclinical pancreatitis at the time of diagnosis was suspected in 33, 50, and 31% of cats based on Spec fPL, DGGR‐lipase and ultrasonography, respectively; and in 60% when diagnostic criteria were combined. During the follow‐up period, suspected pancreatitis developed in additional 17–30% cats. Only 1 cat had transient clinical signs compatible with pancreatitis. Seventeen of the 30 cats (57%) achieved remission. Frequency of abnormal Spec fPL and DGGR‐lipase and abnormal ultrasonographic findings did not differ in cats achieving remission and those who did not. Cats achieving remission had significantly lower Spec fPL at 2 months (P < .001).

Conclusions and Clinical Importance

Based on laboratory and ultrasonographic measurements, many cats with diabetes might have pancreatitis, although without clinical signs. Cats with high Spec fPL might have a reduced chance of diabetic remission; however, this topic needs further studies in large cohorts of diabetic cats.

Intensive intravenous infusion of insulin in diabetic cats

Background

Remission occurs in 10–50% of cats with diabetes mellitus (DM). It is assumed that intensive treatment improves β‐cell function and increases remission rates.

Hypothesis

Initial intravenous infusion of insulin that achieves tight glycemic control decreases subsequent insulin requirements and increases remission rate in diabetic cats.

Animals

Thirty cats with newly diagnosed DM.

Methods

Prospective study. Cats were randomly assigned to one of 2 groups. Cats in group 1 (n = 15) received intravenous infusion of insulin with the goal of maintaining blood glucose concentrations at 90–180 mg/dL, for 6 days. Cats in group 2 (n = 15) received subcutaneous injections of insulin glargine (cats ≤4 kg: 0.5–1.0 IU, q12h; >4 kg 1.5–2.0 IU, q12h), for 6 days. Thereafter, all cats were treated with subcutaneous injections of insulin glargine and followed up for 6 months. Cats were considered in remission when euglycemia occurred for ≥4 weeks without the administration of insulin. Nonparametric tests were used for statistical analysis.

Results

In groups 1 and 2, remission was achieved in 10/15 and in 7/14 cats (P = .46), and good metabolic control was achieved in 3/5 and in 1/7 cats (P = .22), respectively. Overall, good metabolic control or remission occurred in 13/15 cats of group 1 and in 8/14 cats of group 2. In group 1, the median insulin dosage given during the 6‐month follow‐up was significantly lower than in group 2 (group 1: 0.32 IU/kg/day, group 2: 0.51 IU/kg/day; P = .013).

Conclusions and Clinical Importance

Initial intravenous infusion of insulin for tight glycemic control in cats with DM decreases insulin requirements during the subsequent 6 months.

Different design of enzyme-triggered CO-releasing molecules (ET-CORMs) reveals quantitative differences in biological activities in terms of toxicity and inflammation

Acyloxydiene–Fe(CO)₃ complexes can act as enzyme-triggered CO-releasing molecules (ET-CORMs). Their biological activity strongly depends on the mother compound from which they are derived, i.e. cyclohexenone or cyclohexanedione, and on the position of the ester functionality they harbour. The present study addresses if the latter characteristic affects CO release, if cytotoxicity of ET-CORMs is mediated through iron release or inhibition of cell respiration and to what extent cyclohexenone and cyclohexanedione derived ET-CORMs differ in their ability to counteract TNF-α mediated inflammation. Irrespective of the formulation (DMSO or cyclodextrin), toxicity in HUVEC was significantly higher for ET-CORMs bearing the ester functionality at the outer (rac-4), as compared to the inner (rac-1) position of the cyclohexenone moiety. This was paralleled by an increased CO release from the former ET-CORM. Toxicity was not mediated via iron as EC₅₀ values for rac-4 were significantly lower than for FeCl₂ or FeCl₃ and were not influenced by iron chelation. ATP depletion preceded toxicity suggesting impaired cell respiration as putative cause for cell death. In long-term HUVEC cultures inhibition of VCAM-1 expression by rac-1 waned in time, while for the cyclohexanedione derived rac-8 inhibition seems to increase. NFκB was inhibited by both rac-1 and rac-8 independent of IκBα degradation. Both ET-CORMs activated Nrf-2 and consequently induced the expression of HO-1.

This study further provides a rational framework for designing acyloxydiene–Fe(CO)₃ complexes as ET-CORMs with differential CO release and biological activities. We also provide a better understanding of how these complexes affect cell-biology in mechanistic terms.

Abstract P6-05-01: Basal and induced receptor profiles cluster cell lines into subtypes and predict drug response in a panel of breast cancer lines

Molecular subtype is a critical determinant of therapeutic approaches in breast cancer. The subtype is based on the expression of three receptors: The Her2/ErbB2 receptor tyrosine kinase (RTK), whose over-expression defines the HER2amp subtype, and the estrogen or progesterone nuclear hormone receptors, whose over-expression defines the HR+ subtype. Triple negative breast cancers (TNBCs) express low levels of all three receptors. HER2amp status serves as a biomarker for therapy with anti-Her2/ErbB2 antibodies such as trastuzumab or pertuzumab and HR+ status is a biomarker for therapy with hormone receptor antagonists such as tamoxifen. TNBCs are usually treated with cytotoxic chemotherapy. However, breast cancer subtypes are heterogeneous, clinical and mRNA subtypes are not identical, and even the best available biomarker, HER2amp status, correctly predicts response to trastuzumab in only a subset of patients.

Projects such as the Cancer Cell Line Encyclopedia aim to identify drug response determinants by relating dose-response profiles for multiple compounds to genomic features across cancer cell collections. Recent studies have suggested that measures of target activity such as phosphorylation are more correlated with drug response than mutation status or gene expression, and steady-state protein data is becoming available for tumors and cell lines. However, few studies have tried to relate the biochemistry of signal transduction to drug response on a large scale, mainly because the measurements are demanding and the utility of the approach is unproven.

In this work, we ask whether measurement of the basal and perturbed states of immediate-to-early signaling proteins in serum-starved cells, a robust measurement that can be collected with relatively little biological variability, is predictive of tumor subtype as well as of drug response. We measured the abundance and basal phosphorylation state of nuclear and cell surface receptors and of downstream signaling kinases in the standardized NCI-ICBP43 cell line collection. Because perturbation reveals features of signal transduction that are not apparent by steady state profiling, and because biological ligands present in the microenvironment can alter drug sensitivity, we also collected response profiles by exposing cells to a diverse set of growth factors and cytokines and measuring the activities of downstream signaling kinases before and after ligand addition. We present how the resulting set of ∼3×105 receptor and cell response measurements segregated with clinical subtype and how these proteomic measurements predict the sensitivity of cells to a range of targeted anti-cancer drugs.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-05-01.

Enzyme-triggered CO-releasing molecules (ET-CORMs): evaluation of biological activity in relation to their structure

Acyloxydiene-Fe(CO)3 complexes act as enzyme-triggered CO-releasing molecules (ET-CORMs) and can deliver CO intracellularly via esterase-mediated hydrolysis. The protective properties of structurally different ET-CORMs on hypothermic preservation damage and their ability to inhibit VCAM-1 expression were tested on cultured human umbilical vein endothelial cells (HUVEC) and renal proximal tubular epithelial cells (PTEC) using a structure-activity approach. Cytotoxicity of ET-CORMs, protection against hypothermic preservation damage, and inhibition of VCAM-1 expression were assessed. Cytotoxicity of 2-cyclohexenone and 1,3-cyclohexanedione-derived ET-CORMs was more pronounced in HUVEC compared to PTEC and was dependent on the position and type of the ester (acyloxy) substituent(s) (acetate>pivalate>palmitate). Protection against hypothermic preservation injury was only observed for 2-cyclohexenone-derived ET-CORMs and was not mediated by the ET-CORM decomposition product 2-cyclohexenone itself. Structural requirements for protection by these ET-CORMs were different for HUVEC and PTEC. Protection was affected by the nature of the ester functionality in both cell lines. VCAM-1 expression was inhibited by both 2-cyclohexenone- and 1,3-cyclohexanedione-derived ET-CORMs. 2-Cyclohexenone, but not 1,3-cyclohexanedione, also inhibited VCAM-1 expression. We demonstrate that structural alterations of ET-CORMs significantly affect their biological activity. Our data also indicate that different ET-CORMs behave differently in various cell types (epithelial vs endothelial). These findings warrant further studies not only to elucidate the structure-activity relation of ET-CORMs in mechanistic terms but also to assess if structural optimization will yield ET-CORMs with restricted cell specificity.

Probing timescales during back side ablation of Molybdenum thin films with optical and electrical measurement techniques

In this study we present a new measurement technique to investigate the timescales of back side ablation of conductive films, using Molybdenum as an application example from photovoltaics. With ultrashort laser pulses at fluences below 0.6 J/cm(2), we ablate the Mo film in the shape of a fully intact Mo 'disc' from a transparent substrate. By monitoring the time-dependent current flow across a specifically developed test structure, we determine the time required for the lift-off of the disc. This value decreases with increasing laser fluence down to a minimum of 21 ± 2 ns. Furthermore, we record trajectories of the discs using a shadowgraphic setup. Ablated discs escape with a maximum velocity of 150 ± 5 m/s whereas droplets of Mo forming at the center of the disc can reach velocities up to 710 ± 11 m/s.

A high-affinity ErbB4Fc fusion protein is a potent antagonist of heregulin-mediated receptor activation

Ligand-mediated activation of ErbB3 and ErbB4 is implicated in the pathogenesis of several human malignancies including cancer of the ovary and melanoma. We have used the broad ErbB ligand specificity of ErbB4 to assemble and express an ErbB4 fusion protein comprising the first 497 amino acids of the mature ErbB4 ectodomain fused to the human IgG Fc constant region. The purified fusion protein, designated sErbB4.497.Fc, binds the ErbB receptor ligands betacellulin and heregulin-β1 (HRG-β1) with high affinity (K(D) = 130 pM), an increase in affinity of 10- to 20-fold, respectively, compared with sErbB4.615.Fc. sErbB4.497.Fc inhibited ligand-stimulated phosphorylation of epidermal growth factor receptor and ErbB2, and blocked HRG-β1 activation of the IKB/MAP/JNK/AKT signalling pathways. sErbB4.497.Fc inhibited HRG-β1-stimulated proliferation in MCF7 cells. In a mouse tumour xenograft model, sErbB4.497.Fc as a monotherapy modestly inhibited the growth of MDA-MB-231 breast cancer cells. sErbB4.497.Fc may be useful in an adjuvant setting in combination with conventional therapeutic agents.

Review: Fluorescent protein-based tumor models

Numerous animal models have been developed to provide a deeper insight to tumor progression in the search for new therapeutic leverage. The closer the tumor model represents the real tumor disease, the better. The ideal model provides monitoring, tumor cell detection and quantification, and the physiological events involved in tumor progression and tumor dissemination, simultaneously. Sensitive techniques have been developed which involve fluorescent protein-based methods, developed in order to quantify the tumor cells in a whole organ, and in parallel, to visualize the cells. These genetically encoded fluorescent proteins may also be used to develop biological sensors to monitor the physiological reaction of tumor cells within whole organs in living animals. Here, we aim to review past and present work and to show the perspectives of animal models involving fluorescent protein-transfected tumor cells.

[Diabetes remission in cats: a review]

Remission from diabetes is seen in 25 - 50 % of cats during the first months of therapy. The likelihood of remission is higher in old cats and cats with normal cholesterol than in young cats and cats with increased cholesterol. The results of an ongoing study indicate that initial intravenous insulin therapy has positive effects on remission rates and quality of metabolic control.

Deterministic characterization of phase noise in biomolecular oscillators

On top of the many external perturbations, cellular oscillators also face intrinsic perturbations due the randomness of chemical kinetics. Biomolecular oscillators, distinct in their parameter sets or distinct in their architecture, show different resilience with respect to such intrinsic perturbations. Assessing this resilience can be done by ensemble stochastic simulations. These are computationally costly and do not permit further insights into the mechanistic cause of the observed resilience. For reaction systems operating at a steady state, the linear noise approximation (LNA) can be used to determine the effect of molecular noise. Here we show that methods based on LNA fail for oscillatory systems and we propose an alternative ansatz. It yields an asymptotic expression for the phase diffusion coefficient of stochastic oscillators. Moreover, it allows us to single out the noise contribution of every reaction in an oscillatory system. We test the approach on the one-loop model of the Drosophila circadian clock. Our results are consistent with those obtained through stochastic simulations with a gain in computational efficiency of about three orders of magnitude.

Subacute endotoxemia induces adipose inflammation and changes in lipid and lipoprotein metabolism in cats

Acute inflammation in humans is associated with transient insulin resistance (IR) and dyslipidemia. Chronic low-grade inflammation is a pathogenic component of IR and adipose tissue dysfunction in obesity-induced type 2 diabetes. Because feline diabetes closely resembles human type 2 diabetes, we studied whether lipopolysaccharide (LPS)-induced subacute inflammation, in the absence of obesity, is the potential primary cause of IR and metabolic disorders. Cats received increasing iv doses (10-1000 ng/kg(-1) · h(-1)) of LPS (n = 5) or saline (n = 5) for 10 d. Body temperature, proinflammatory and metabolic markers, and insulin sensitivity were measured daily. Tissue mRNA and protein expression were quantified on d 10. LPS infusion increased circulating and tissue markers of inflammation. Based on the homeostasis model assessment, endotoxemia induced transient IR and β-cell dysfunction. At the whole-body level, IR reverted after the 10-d treatment; however, tissue-specific indications of IR were observed, such as down-regulation of adipose glucose transporter 4, hepatic peroxisome proliferative activated receptor-γ1 and -2, and muscle insulin receptor substrate-1. In adipose tissue, increased hormone-sensitive lipase activity led to reduced adipocyte size, concomitant with increased plasma and hepatic triglyceride content and decreased total and high-density lipoprotein cholesterol levels. Prolonged LPS-induced inflammation caused acute IR, followed by long-lasting tissue-specific dysfunctions of lipid-, glucose-, and insulin metabolism-related targets; this ultimately resulted in dyslipidemia but not whole-body IR. Endotoxemia in cats may provide a promising model to study the cross talk between metabolic and inflammatory responses in the development of adipose tissue dysfunction and IR.

Predictors of clinical remission in cats with diabetes mellitus

BACKGROUND

Clinical remission is frequent in cats with well-controlled diabetes mellitus, but few studies explored predictors of this phenomenon.

HYPOTHESIS

Data retrieved from medical records at admission might be valuable to identify likelihood of remission and its duration in diabetic cats.

ANIMALS

Ninety cats with newly diagnosed diabetes, followed-up until death or remission.

METHODS

Retrospective cohort study. Data were collected from records at admission, including history, signalment, physical examination, haematology, and biochemical profile, and the occurrence and duration of remission, defined as normoglycemia without insulin for ≥4 weeks. Predictors of remission were studied with univariate and multivariate logistic regression. Factors associated with remission duration were analyzed with Kaplan-Meier and Cox proportional hazard models.

RESULTS

Forty-five (50%) cats achieved remission, after a median time of 48 days (range: 8-216). By study end, median remission duration was 114 days (range: 30-3,370) in cats that died and 151 days (range: 28-1,180) in alive cats. Remission was more likely with higher age (OR: 1.23, 95% CI: 1.04-1.46; P=.01) and less likely with increased serum cholesterol (OR: 0.36, 95% CI: 0.11-0.87; P=.04). Remission was longer with higher body weight (HR: 0.65, 95% CI: 0.42-0.99; P=.04) and shorter with higher blood glucose (HR: 1.01, 95% CI: 1.00-1.02; P=.02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Age, body weight, cholesterol, and glucose levels are suggested for prediction of remission or its duration in diabetic cats. Older cats developing diabetes may have a better outcome, possibly suggesting a slower disease progression.

Visualization of the Ca-transport system of the mitotic apparatus of sea urchin eggs with a monoclonal antibody

Monoclonal antibodies have been obtained to components of Ca(2+)-sequestering vesicles from the endoplasmic reticulum of HeLa cells by isolating hybridomas that were generated by the in vitro immunization of lymphocytes followed by fusion with plasmocytoma cells. One of these monoclonal antibodies specifically labels punctate structures which appear in the mitotic apparatus of sea urchin eggs at the beginning of prophase and disappear upon the completion of cytokinesis. The antibody inhibits the Ca(2+) uptake of the membrane system in vitro. It reacts with one 46-kDa protein out of the complex protein mixture from the membrane fraction. We take all this as evidence that in fact a specific Ca(2+)-transport system is part of the mitotic apparatus, that such a system is very conserved, and that it is most probably derived from the endoplasmic reticulum.

Functional knockdown of VCAM-1 at the posttranslational level with ER retained antibodies

Vascular cell adhesion molecule 1 (VCAM-1) is involved in the recruitment of leukocytes to inflammatory sites. In this study we present the first functional knockdown of VCAM-1 using an ER retained antibody construct. We generated a knockdown construct encoding the VCAM-1 specific single chain variable fragment scFv6C7.1 fused to the C-terminal ER retention sequence KDEL. HEK-293:VCAM-YFP cells stably expressing a VCAM-YFP fusion protein were transiently transfected with the knockdown construct and showed down-regulation of surface VCAM-1. Knockdown efficiency of the system is time-dependent due to used transient transfection of the intrabody construct. Furthermore, intrabody mediated knockdown of HEK-293:VCAM-YFP cells also impaired cell-cell interaction with Jurkat cells that are endogenously expressing VLA-4, the physiological partner of VCAM-1. Posttranslational knockdown with ER retained antibodies seems to be a promising technique, as shown here for VCAM-1.

Stability and epimerisation behaviour of ergot alkaloids in various solvents

In this paper the stability and degree of epimerisation of six major ergot alkaloids at three different temperature levels (-20 °C, +4 °C and +20 °C) over periods of 18 hours and six weeks is reported for the first time. The behaviour of ergometrine, ergocornine, ergocristine, α-ergocryptine, ergosine and ergotamine was thoroughly studied in seven solvents which are employed for the preparation of calibrants and extraction mixtures, respectively. Moreover, the stability of the ergot alkaloids was tested in different cereal extracts (rye, wheat, barley, oats) for 1, 2 and 6 days. Of the toxins tested, the ergopeptide-type toxins ergosine, ergotamine, ergocornine, α-ergocryptine and ergocristine showed similar behaviour patterns. The simple lysergic acid derivative ergometrine was more stable and showed hardly any epimerisation to ergometrinine, with the sum of both epimers remaining constant in all seven solvents. The ergopeptides tested show variable epimerisation tendencies, and were also less stable during six weeks at 20 °C. Ergosine showed the highest degree of epimerisation (43% after 6 weeks at 20 °C). In general, the order of epimerisation promotion was methanol/dichloromethane > acetonitrile/buffer > extraction mix > stabilising solution > acetonitrile >> chloroform. Long-term storage at room temperature can only be carried out in chloroform, which showed no epimerisation for all toxins even at 20 °C and also kept the sum of R and S forms constant, which indicates no formation of aci-epimers or other degradation products. Long-term storage of ergot alkaloids in acetonitrile, the most convenient solvent with respect to HPLC analysis, should be carried out at temperatures of -20 °C or below. The constant epimer ratio of all ergot alkaloids in the extraction mixture acetonitrile/ammonium carbonate buffer (200 mg/l; 92:8, v/v) during an HPLC run (18 hours) demonstrates the stability of the toxins in this extraction mixture.

Respiratory Deleted in Malignant Brain Tumours 1 (DMBT1) levels increase during lung maturation and infection

Deleted in Malignant Brain Tumours 1 (DMBT1) is a secreted scavenger receptor cysteine-rich protein that binds and aggregates various bacteria and viruses in vitro. Studies in adults have shown that DMBT1 is expressed mainly by mucosal epithelia and glands, in particular within the respiratory tract, and plays a role in innate immune defence. We hypothesized that respiratory DMBT1 levels may be influenced by various developmental and clinical factors such as maturity, age and bacterial infection. DMBT1 levels were studied in 205 tracheal aspirate samples of 82 ventilated preterm and full-term infants by enzyme-linked immunosorbent assay. Possible effects of various clinical parameters were tested by multiple regression analysis. DMBT1 levels increased significantly with lung maturity (P < 0.0001 for both gestational and postnatal age) and in small-for-gestational-age infants (P = 0.0179). An increase of respiratory DMBT1 levels was detected in neonatal infections (P < 0.0001). These results were supported by Western blotting. Immunohistochemical analyses of archived newborn lung sections (n = 17) demonstrated high concentrations of DMBT1 in lungs of neonates with bacterial infections. Our data show that preterm infants are able to up-regulate DMBT1 in infection as an unspecific immune reaction.

Expression of the p210BCR-ABL oncoprotein drives centrosomal hypertrophy and clonal evolution in human U937 cells

Centrosomes play fundamental roles in mitotic spindle organization, chromosome segregation and maintenance of genetic stability. Recently, we have shown that centrosome aberrations occur early in chronic myeloid leukemia (CML) and are induced by imatinib in normal fibroblasts in vitro. To investigate the influence of BCR-ABL on centrosomes, we performed long-term in vitro experiments employing the conditionally p210BCR-ABL-expressing (tetracycline-inducible promoter) human monocytic cell line U937p210BCR-ABL/c6 as a model of CML chronic phase. Centrosome hypertrophy was detectable after 4 weeks of transgene expression onset, increasing up to a rate of 25.7% aberrant cells within 13 weeks of propagation. This concurred with clonal expansion of aneuploid cells displaying a hyperdiploid phenotype with 57 chromosomes. Partial reversibility of centrosome aberrations (26-8%) was achieved under prolonged propagation (14 weeks) after abortion of induction and bcr-abl silencing using small interfering RNA. Therapeutic doses of imatinib did not revert the aberrant phenotype, but counteracted the observed reverting effect of bcr-abl gene expression switch off. Suggesting a mechanistic model that features distinct abl-related tyrosine kinase activity levels as essential determinants of centrosomal integrity, this is the first report mechanistically linking p210BCR-ABL oncoprotein activity to centrosomal hypertrophy.

Peritoneal cancer treatment with CYP2B1 transfected, microencapsulated cells and ifosfamide

The prognosis of peritoneal spread from gastrointestinal cancer and subsequent malignant ascites is poor, and current medical treatments available are mostly ineffective. Targeted chemotherapy with intraperitoneal prodrug activation may be a beneficial new approach. L293 cells were genetically modified to express the cytochrome P450 enzyme 2B1 under the control of a cytomegalovirus immediate early promoter. This CYP2B1 enzyme converts ifosfamide to its active cytotoxic compounds. The cells are encapsulated in a cellulose sulfate formulation (Capcell). Adult Balb/c mice were inoculated intraperitoneally with 1 x 10(6) colon 26 cancer cells, previously transfected with GFP to emit a stable green fluorescence, by injection into the left lower abdominal quadrant. Two or five day's later animals were randomly subjected to either i.p. treatment with ifosfamide alone or ifosfamide combined with microencapsulated CYP2B1-expressing cells. Peritoneal tumor volume and tumor viability were assessed 10 days after tumor inoculation by means of fluorescence microscopy, spectroscopy and histology. Early i.p. treatment with ifosfamide and CYP2B1 cells resulted in a complete response. Treatment starting on day 5 and single-drug treatment with ifosfamide resulted in a partial response. These results suggest that targeted i.p. chemotherapy using a combination of a prodrug and its converting enzyme may be a successful treatment strategy for peritoneal spread from colorectal cancer.

Targeted tumor therapy with the TGF-beta2 antisense compound AP 12009 for the treatment of advanced solid tumors

14012

Background: TGF-β overexpression in advanced tumors is correlated with tumor-induced immunosuppression, proliferation and angiogenesis. Furthermore, it is a key factor for induction of epithelial to mesenchymal transition (EMT), thus promoting invasion and metastasis. Targeted tumor therapy by an antisense oligonucleotide has already been proven to be successful in tumor therapy: AP 12009, a TGF-β2-mRNA-specific antisense oligodeoxynucleotide, has shown strong clinical indication of efficacy including complete and lasting remissions in malignant glioma. Methods: Spurred by the highly encouraging clinical data in malignant glioma and strong anti-tumor activity in a wide variety of preclinical assays, clinical studies in further indications were initiated. A multi-center dose-escalation phase I/II trial with AP 12009 in patients suffering from advanced solid tumors was started in 2005. Primary endpoint is to assess the maximum tolerated dose (MTD) as well as the dose-limiting toxicity (DLT). AP 12009 is administered i.v. in 14-day cycles. Results: Preclinically, in human pancreatic cancer and melanoma cell cultures AP 12009 significantly reduced the TGF-β2 secretion of cancer cells, inhibited tumor cell proliferation, and blocked migration of cancer cells. Additionally, AP 12009 reversed TGF-β2 mediated immunosuppression induced by pancreatic carcinoma cells. In the ongoing clinical phase I/II dose-escalation study, two cohorts of tumor patients have already been treated intravenously with AP 12009 as of Dec 2005. Further dose escalations are ongoing. So far, no DLT, no possibly related SAEs and only seven possibly related AEs were observed. MTD is not yet reached. The majority of patients received more than the minimum number of two cycles, one of them received ten full cycles. First signs of efficacy could also be observed. Conclusions: In conclusion, the preclinical results with pancreatic cancer and malignant melanoma cell cultures as well as the successful clinical application of AP 12009 in the lead indication malignant glioma form a rational basis for the use of the antisense compound AP 12009 as targeted therapy of advanced, TGF-β2 overexpressing tumors.

[Table: see text]

Centrosome aberrations in chronic myeloid leukemia correlate with stage of disease and chromosomal instability

Centrosome abnormalities are hallmarks of various cancers and have been implicated in chromosome missegregation, chromosomal instability, and aneuploidy. Since genetic instability is a common feature in chronic myeloid leukemia (CML), we sought to investigate whether centrosome aberrations occur and correlate with disease stage and cytogenetic findings in CML. We examined 34 CML samples including CD 34+Ph+cells of 18 newly diagnosed patients (chronic phase (CP)) and 16 blast crisis (BC) specimens by using a centrosome-specific antibody to pericentrin. All CP and BC samples displayed centrosome alterations as compared with corresponding CD 34+control cells. Centrosome abnormalities were detected in 29.1+/-5.9% of CP blasts and in 54.3+/-4.8% of BC blasts, but in only 2.4+/-1.1% of controls (P<0.0001). Additional karyotypic alterations to the t(9;22) translocation were found in only 1/18 CML-CP patients. In contrast, 11/16 (73%) CML-BC patients displayed additional karyotype alterations in 48.7% of analyzed cells, correlating with an abnormal centrosome status (P=0.0005). Our results indicate that centrosome defects are a common and early detectable feature in CML that may contribute to acquisition of chromosomal aberrations and aneuploidy. They may be considered as the driving force of disease progression and could serve as future prognostic markers.

Activation of phospholipase C-?1 in human keratinocytes by hyperosmolar shock without enzyme phosphorylation

Human keratinocytes are exposed to strong physical changes, and have the potentiality to react to external stimuli by switching on adaptation mechanisms. In hyperosmotically shocked keratinocytes a rapid and strong increase in calcium has been observed. We showed that this increase could not be prevented by growing the cells in medium devoid of calcium and in the presence of EGTA, indicating that the intracellular calcium increase was due to delivery from internal stores. Further, we observed an increased synthesis of dyacylglycerol and inositol trisphosphates after shock, suggesting that phospholipase C mediates both events. Our experiments demonstrated that osmotic shock in human keratinocytes leads to activation of phospholipase C-gamma1, as measured using an in vitro assay system. This activation is independent of protein tyrosine phosphorylation and corresponded to a relocation of the enzyme to perinuclear membranes as shown by immunofluorescence.

A 14-mer Hsp70 peptide stimulates natural killer (NK) cell activity

Compared with normal cells, tumor cell lines exhibit an unusual plasma membrane localization of heat shock protein 70 (Hsp70). This tumor-selective Hsp70 membrane expression has been found to correlate with an increased sensitivity to lysis mediated by human natural killer (NK) cells that transiently adhere to plastic following cytokine stimulation. A human Hsp70-specific monoclonal antibody (mAb) detects membrane-bound Hsp70 on viable tumor cells and blocks the immune response of NK cells against Hsp70-expressing tumor cells. By peptide scanning (pep-scan) analysis, the epitope of this mAb was mapped as the C-terminal-localized 8-mer NLLGRFEL (NLL, amino acids [aa] 454-461). Most interestingly, similar to full-length Hsp70 protein, the N-terminal-extended 14-mer peptide TKDNNLLGRFELSG (TKD, aa 450-463) was able to stimulate the cytolytic and proliferative activity of NK cells at concentrations equivalent to full-length Hsp70 protein. Blocking studies revealed that an excess of the 14-mer peptide TKDNNLLGRFELSG inhibits the cytolytic activity of NK cells similar to that of Hsp70 protein. In comparison, other TKD-related peptides, including the 8-mer antibody epitope NLLGRFEL (aa 454-461), the 12-mer TKDNNLLGRFEL (aa 450-461), the 13-mer C-terminal-extended peptide NLLGRFELSGIPP (aa 454-466), the 14-mer TKD-equivalent sequences of Hsp70hom TKDNNLLGRFELTG (aa 450-463), Hsc70 TKDNNLLGKFELTG (aa 450-463), and DnaK AADNKSLGQFNLDG (aa 447-460) failed to activate NK activity.

Decreased glomerular expression of agrin in diabetic nephropathy and podocytes, cultured in high glucose medium

AIM

A decrease in glomerular heparan sulfate (HS) proteoglycan (PG), without apparent decrease in HSPG core protein expression, has been reported to occur in diabetic nephropathy (DN). In most studies however, agrin, the major HSPG core protein in the glomerular basement membrane, has not been studied. This prompted us to study the glomerular expression of agrin in parallel to the expression of HS-glycosaminoglycans (GAG) in biopsies of patients with DN. Furthermore, the influence of glucose on agrin production in cultured podocytes and the expression of agrin in fetal kidneys was investigated.

METHODS

Cryostat sections of renal biopsies from patients with DN (n = 8) and healthy controls (HC, n = 8), were stained for agrin and HS-GAG. Sections of fetal kidneys were double stained for agrin and CD35 or CD31. Stainings were performed by indirect immunofluorescence (IIF). The production of agrin by cultured human podocytes was tested by ELISA and IIF.

RESULTS

The expression of agrin, detected by AS46, was significantly reduced in biopsies from patients with DN compared to HC (p < 0.01). Similar findings were observed when monoclonal antibody JM72 was used (p < 0.05). In addition, a significant reduction in the glomerular expression of HS-GAG was detected with JM403 in these patients (p < 0.01). Agrin is expressed in cultured podocytes, the expression hereof was reduced when the cells were cultured in the presence of 25 mM D-glucose (p < 0.01). In biopsies of human fetal kidneys, glomerular expression of agrin coincided with the expression of CD31. In early stages of glomerular differentiation there was a strong staining for agrin and CD31 while CD35 was only slightly positive.

CONCLUSIONS

Our data argue against a selective dysregulation in HSPG sulfation in DN, but suggest a pivotal role for hyperglycemia in the downregulation of agrin core protein production.

Antimetastatic effect of CpG DNA mediated by type I IFN

The mechanisms involved in the antimetastatic effect of CpG-containing DNA were investigated in a mouse model of experimental metastasis. Tumor cell colony formation in lungs or livers of mice after i.v. inoculation with syngeneic fibrosarcoma or thymoma cells was determined. The i.v. injection of plasmid DNA or synthetic oligodeoxynucleotides (ODNs) containing unmethylated CpG motifs before tumor cell application strongly inhibited metastasis. Because synthetic CpG-ODN was not directly tumor cytotoxic, the target cells for this CpG-ODN effect were determined. The cytotoxic activity on standard natural killer (NK) targets as well as on fibrosarcoma cells of splenic NK cells and NKT cell-containing liver mononuclear cells derived from CpG-ODN-treated mice was strongly enhanced. Participation of NK/NKT cells in the CpG-induced antimetastatic effect was demonstrated by reduction of the antimetastatic effect in mice depleted of NK/NKT cells and beta2-microglobulin-deficient mice. Neutralization of interleukin 12, interleukin 18, or IFN-gamma did not interfere with the CpG-induced antimetastatic effect. However, in sera of CpG-ODN-treated mice, high levels of IFN-alpha were detected, and in IFN-alpha/beta receptor-deficient mice, the CpG-ODN-induced antimetastatic effect was strongly reduced. These data indicate that CpG-ODNs activate NK/NKT cells for antimetastatic activity indirectly via IFN-alpha/beta receptor activation. The exploitation of the stimulatory activity of CpG-ODN for the innate immune system might be a useful strategy for antimetastatic therapy.

Angiotensin II type 1 receptor regulation and differential trophic effects on rat cardiac myofibroblasts after acute myocardial infarction

Fibroblast growth in the scar and surviving tissue is a key element of the remodeling post myocardial infarction. The regulation of fibroblast growth after acute myocardial infarction remains to be determined. Recently, Angiotensin II has been demonstrated to be a mitogen for neonatal cardiac fibroblasts. In this study adult rat cardiac fibroblasts were isolated from different regions of the infarcted rat heart and Angiotensin II effects examined. Adult Wistar-rats were sham operated or left coronary artery ligated. After 4 days, hearts were removed and fibroblasts from sham operated, infarct- and non-infarct regions of the left ventricle isolated. Radioligand binding studies were performed and cell number, cell area, total protein, and AT(1) receptor mRNA after stimulation determined. Radioligand binding studies demonstrated that myofibroblasts expressed a single class of high affinity Angiotensin II AT(1) receptors. Myofibroblasts from the infarct area revealed a lower maximal binding capacity, compared to sham operated myocardium. Conversely, myofibroblasts from the non-infarct area had a higher expression of Angiotensin II AT(1) receptor mRNA compared to sham operated myofibroblasts. Angiotensin II (1 microM, 48 h) increased cell-number in sham operated and non-infarct, but not in infarct myofibroblasts. Angiotensin II elevated total protein in sham operated, non-infarct, and infarct myofibroblasts. In addition, Angiotensin II increased cell area in sham operated and infarct myofibroblasts. These data demonstrate that Angiotensin II acted as a mitogen in sham operated and non-infarct myofibroblasts and stimulated hypertrophy in infarct myofibroblasts. These regional different effects of Angiotensin II might participate in the remodeling post myocardial infarction.

Lectin-deficient TNF mutants display comparable anti-tumour but reduced pro-metastatic potential as compared to the wild-type molecule

In this study, we characterised the anti-tumour as well as the pro-metastatic activities of TNF mutants deficient in their lectin-like activity.1619 We report that, despite reduced systemic toxicity as compared to wild-type (wt) mTNF, a (T104A) and a (T104A-E106A-E109A) mTNF mutant (triple mTNF) retained most of their necrotic and tumouristatic activities, as measured in a CFS-1 fibrosarcoma and a B16BL6 melanoma tumour model, respectively. These mutants also conserved their anti-angiogenic activity, as measured in an in vitro endothelial morphogenesis assay.26 In contrast, the pro-metastatic activity of the T104A and the triple mTNF mutants in the CFS-1 fibrosarcoma and the 3LL-R Lewis lung carcinoma tumour model was significantly lower than that of the wt molecule. These results thus indicate that the lectin-like domain of TNF is not implicated in its necrotic, tumouristatic and anti-angiogenic activities, but that it can contribute to the pro-metastatic effect of the cytokine. In conclusion, in view of their reduced systemic toxicity and pro-metastatic capacity, but their retained anti-tumour activities, lectin-deficient TNF mutants might prove to be therapeutically interesting alternatives to wt TNF.

Characterization of a postreceptor signaling defect that impairs cfos expression in cultured fibroblasts of a patient with insulin resistance

Induction of cfos expression is a definite end point of signal transduction by receptor tyrosine kinases via MAPK cascades. We have examined signal transduction to transcription factor cFos in isolated fibroblasts of a patient with an inherited syndrome of insulin resistance. MAPK phosphorylation and activity were unaltered, but inducibility of cfos transcription was strongly impaired by insulin and reduced by PDGF. Induction of the cfos promoter via MAPK is mediated by activation of the ternary complex. Abundance of SRF or Elk-1 was unaltered, but Elk-1 phosphorylation following stimulation was reduced. Transient transfections with reporter genes under control of the Elk-1 binding ets/sre cis element or expression plasmids coding for the regulatory domain of Elk-1 fused to heterologous DNA binding domains revealed a defect of Elk-1 activation in the patient cells. These data identify a novel postreceptor defect of insulin and growth factors involving activation of transcription.

Erythema migrans and serodiagnosis by enzyme immunoassay and immunoblot with three borrelia species

There is wide divergence of opinion between physicians regarding the use of serological measures for the diagnosis and treatment of erythema migrans, the hallmark of Lyme borreliosis. We studied the outcome of an enzyme immunoassay and immunoblot (Western blot) used on the sera of patients who had suffered tick bite and erythema migrans, and had been subsequently treated with various antibiotics. Ninety-nine consecutive patients presenting with erythema migrans after tick bite were prospectively recruited at the outpatient department of two Vienna City hospitals and at the consultation office for Lyme borreliosis of the Institute of Hygiene. University Vienna. Blood samples were taken before antibiotic treatment and 3 and 6 months thereafter. Blood samples from 100 blood donors served as controls. Antibodies against Borrelia burgdorferi sensu lato were determined by enzyme immunoassay (IgG and IgM EIA) and by IgG immunoblot. The latter was performed with isolates of B. alzelii (H2) B. burgdorferi sensu stricto (Le) and B. garinii (W) from Austrian patients. The 4 interpretation criteria for immunoblot results were: A (3 bands out of 8), B (2 bands out of 9), C and D (1 band out of 6). In all patients, the erythema resolved within the treatment period. No complications secondary to the borrelia infection were registered. After treatment there was no significant change in titre, nor was there a difference in the immunoblot pattern between the first, second and third serum samples. Serum antibodies to B. burgdorferi were positive by EIA in 22.9% (IgG) and 2.5% (IgM). Immunoblot results offered by borrelia species and by the interpretation criteria, ranging between 8.3% (criterion A, strain Le) and 44.2% (criterion D, strain H2). By EIA, control samples were IgG and IgM positive in 5% and 1%, respectively. Positive immunoblot results with strain H2 were found in 9%, 13%, 18%, and 20% by the criteria A through D respectively. After antibiotic treatment of erythema migrans the immunological response appears to be abrogated. Thus, serological results are not supportive for the diagnosis of erythema migrans, not will they retrospectively prove successful antibiotic treatment of borrelia infection.