Publications by authors named "Arndt Brachat"

10 Publications

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Early changes in gene expression and inflammatory proteins in systemic juvenile idiopathic arthritis patients on canakinumab therapy.

Arthritis Res Ther 2017 01 23;19(1):13. Epub 2017 Jan 23.

Istituto Giannina Gaslini, Pediatria II-PRINTO, Genoa, Italy.

Background: Canakinumab is a human anti-interleukin-1β (IL-1β) monoclonal antibody neutralizing IL-1β-mediated pathways. We sought to characterize the molecular response to canakinumab and evaluate potential markers of response using samples from two pivotal trials in systemic juvenile idiopathic arthritis (SJIA).

Methods: Gene expression was measured in patients with febrile SJIA and in matched healthy controls by Affymetrix DNA microarrays. Transcriptional response was assessed by gene expression changes from baseline to day 3 using adapted JIA American College of Rheumatology (aACR) response criteria (50 aACR JIA). Changes in pro-inflammatory cytokines IL-6 and IL-18 were assessed up to day 197.

Results: Microarray analysis identified 984 probe sets differentially expressed (≥2-fold difference; P < 0.05) in patients versus controls. Over 50% of patients with ≥50 aACR JIA were recognizable by baseline expression values. Analysis of gene expression profiles from patients achieving ≥50 aACR JIA response at day 15 identified 102 probe sets differentially expressed upon treatment (≥2-fold difference; P < 0.05) on day 3 versus baseline, including IL-1β, IL-1 receptors (IL1-R1 and IL1-R2), IL-1 receptor accessory protein (IL1-RAP), and IL-6. The strongest clinical response was observed in patients with higher baseline expression of dysregulated genes and a strong transcriptional response on day 3. IL-6 declined by day 3 (≥8-fold decline; P < 0.0001) and remained suppressed. IL-18 declined on day 57 (≥1.5-fold decline, P ≤ 0.002).

Conclusions: Treatment with canakinumab in SJIA patients resulted in downregulation of innate immune response genes and reductions in IL-6 and clinical symptoms. Additional research is needed to investigate potential differences in the disease mechanisms in patients with heterogeneous gene transcription profiles.

Trial Registration: Clinicaltrials.gov: NCT00886769 (trial 1). Registered on 22 April 2009; NCT00889863 (trial 2). Registered on 21 April 2009.
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http://dx.doi.org/10.1186/s13075-016-1212-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5260050PMC
January 2017

Gene-expression analysis of adult-onset Still's disease and systemic juvenile idiopathic arthritis is consistent with a continuum of a single disease entity.

Pediatr Rheumatol Online J 2015 Nov 20;13:50. Epub 2015 Nov 20.

Novartis Pharma AG, CH-4002, Basel, Switzerland.

Background: Adult-onset Still's disease (AOSD), a rare autoinflammatory disorder, resembles systemic juvenile idiopathic arthritis (SJIA). The superimposable systemic clinical features of AOSD and SJIA suggest both clinical phenotypes represent the same disease continuum with different ages of onset. To further characterize the similarity between AOSD and SJIA at the molecular level, 2 previously identified response gene sets in SJIA were used to investigate how genes that respond to interleukin (IL)-1β inhibition with canakinumab in SJIA patients behave in AOSD patients with active disease prior to IL-1β targeting therapy, relative to healthy subjects.

Findings: All genes downregulated in SJIA patients following canakinumab treatment were upregulated in most patients with active AOSD prior to canakinumab treatment, relative to healthy subjects. A few patients with milder AOSD had expectedly gene-expression patterns that resembled those in healthy subjects. Comparison of the gene-expression patterns with neutrophil counts showed a correlation between elevated neutrophil numbers and upregulation of canakinumab-responsive genes. Correspondingly, most genes upregulated following canakinumab treatment in patients with SJIA patients were downregulated in the majority of AOSD patients.

Conclusions: These results further support the concept of a Still's disease continuum that includes both a pediatric/juvenile onset (SJIA) and adult onset (AOSD) form.
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http://dx.doi.org/10.1186/s12969-015-0047-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4654831PMC
November 2015

Anti-interleukin-17A monoclonal antibody secukinumab in treatment of ankylosing spondylitis: a randomised, double-blind, placebo-controlled trial.

Lancet 2013 Nov 13;382(9906):1705-13. Epub 2013 Sep 13.

Department of Clinical Immunology and Rheumatology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.

Background: Ankylosing spondylitis is a chronic immune-mediated inflammatory disease characterised by spinal inflammation, progressive spinal rigidity, and peripheral arthritis. Interleukin 17 (IL-17) is thought to be a key inflammatory cytokine in the development of ankylosing spondylitis, the prototypical form of spondyloarthritis. We assessed the efficacy and safety of the anti-IL-17A monoclonal antibody secukinumab in treating patients with active ankylosing spondylitis.

Methods: We did a randomised double-blind proof-of-concept study at eight centres in Europe (four in Germany, two in the Netherlands, and two in the UK). Patients aged 18-65 years were randomly assigned (in a 4:1 ratio) to either intravenous secukinumab (2×10 mg/kg) or placebo, given 3 weeks apart. Randomisation was done with a computer-generated block randomisation list without a stratification process. The primary efficacy endpoint was the percentage of patients with a 20% response according to the Assessment of SpondyloArthritis international Society criteria for improvement (ASAS20) at week 6 (Bayesian analysis). Safety was assessed up to week 28. This study is registered with ClinicalTrials.gov, number NCT00809159.

Findings: 37 patients with moderate-to-severe ankylosing spondylitis were screened, and 30 were randomly assigned to receive either intravenous secukinumab (n=24) or placebo (n=6). The final efficacy analysis included 23 patients receiving secukinumab and six patients receiving placebo, and the safety analysis included all 30 patients. At week 6, ASAS20 response estimates were 59% on secukinumab versus 24% on placebo (99·8% probability that secukinumab is superior to placebo). One serious adverse event (subcutaneous abscess caused by Staphylococcus aureus) occurred in the secukinumab-treated group.

Interpretation: Secukinumab rapidly reduced clinical or biological signs of active ankylosing spondylitis and was well tolerated. It is the first targeted therapy that we know of that is an alternative to tumour necrosis factor inhibition to reach its primary endpoint in a phase 2 trial.

Funding: Novartis.
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http://dx.doi.org/10.1016/S0140-6736(13)61134-4DOI Listing
November 2013

A microarray analysis of full depth knee cartilage of ovariectomized rats.

BMC Res Notes 2011 Mar 15;4:63. Epub 2011 Mar 15.

Cartilage biology and biomarkers, Nordic Bioscience, Herlev, Denmark.

Background: This short communication focuses the on articular cartilage and the subchondral bone, both of which play important roles in the development of osteoarthritis (OA). There are indications that estrogen-deficiency, as the post-menopausal state, accelerate the development of OA.

Findings: We investigated, which extracellular matrix (ECM) protein, proteases and different pro-inflammatory factors was up- or down-regulated in the knee joint tissue in response to estrogen-deficiency in rats induced by ovariectomy. These data support previous findings that several metalloproteinases (MMPs) and cysteine proteases are co-regulated with numerous collagens and proteoglycans that are important for cartilage integrity. Furthermore quite a few pro-inflammatory cytokines were regulated by estrogen deprivation.

Conclusion: We found multiple genes where regulated in the joint by estrogen-deficiency, many of which correspond well with our current knowledge of the pathogenesis of OA. It supports that estrogen-deficiency (e.g. OVX) may accelerate joint deterioration. However, there are also data that draw attention the need for better understanding of the synergy between proteases and tissue turnover.
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http://dx.doi.org/10.1186/1756-0500-4-63DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068969PMC
March 2011

Modulation of drug resistance by artificial transcription factors.

Mol Cancer Ther 2008 Mar 4;7(3):688-97. Epub 2008 Mar 4.

Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.

The efficiency of chemotherapeutic treatments in cancer patients is often impaired by the acquisition of drug resistance. Cancer cells develop drug resistance through dysregulation of one or more genes or cellular pathways. To isolate efficient regulators of drug resistance in tumor cells, we have adopted a genome-wide scanning approach based on the screening of large libraries of artificial transcription factors (ATFs) made of three and six randomly assembled zinc finger domains. Zinc finger libraries were linked to a VP64 activation domain and delivered into a paclitaxel-sensitive tumor cell line. Following drug treatment, several ATFs were isolated that promoted drug resistance. One of these ATFs, 3ZF-1-VP, promoted paclitaxel resistance in cell lines having mutated or inactivated p53, such as MDA-MB-435 and Kaposi's sarcoma cell lines. 3ZF-1-VP also induced strong resistance to etoposide, vincristine, and cisplatinum. Linkage of a repression domain to the selected ATF resulted in enhanced sensitivity to multiple drugs, particularly vincristine, cisplatinum, and 5-fluorouracil. Small interfering RNA-mediated inhibition of p53 revealed that 3ZF-1-VP activated both p53-dependent and p53-independent mechanisms to promote survival, whereas other ATF required intact p53. Real-time expression analysis and DNA microarrays showed that several ATFs up-regulated targets of p53, such as the cyclin-dependent kinase inhibitor p21(WAF1/CIP1), and genes participating in the p14(ARF)-MDM2-p53 tumor suppressor pathway, such as hDMP1. Thus, ATF can be used to map genes and pathways involved in drug resistance phenotypes and have potential as novel therapeutic agents to inhibit drug resistance.
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http://dx.doi.org/10.1158/1535-7163.MCT-07-0381DOI Listing
March 2008

PHTS, a novel putative tumor suppressor, is involved in the transformation reversion of HeLaHF cells independently of the p53 pathway.

Exp Cell Res 2006 Apr 17;312(6):865-76. Epub 2006 Jan 17.

Immusol, Inc. 10790 Roselle Street, San Diego, CA 92121, USA.

HeLaHF is a non-transformed revertant of HeLa cells, likely resulting from the activation of a putative tumor suppressor(s). p53 protein was stabilized in this revertant and reactivated for certain transactivation functions. Although p53 stabilization has not conclusively been linked to the reversion, it is clear that the genes in p53 pathway are involved. The present study confirms the direct role of p53 in HeLaHF reversion by demonstrating that RNAi-mediated p53 silencing partially restores anchorage-independent growth potential of the revertant through the suppression of anoikis. In addition, we identified a novel gene, named PHTS, with putative tumor suppressor properties, and showed that this gene is also involved in HeLaHF reversion independently of the p53 pathway. Expression profiling revealed that PHTS is one of the genes that is up-regulated in HeLaHF but not in HeLa. It encodes a putative protein with CD59-like domains. RNAi-mediated PHTS silencing resulted in the partial restoration of transformation (anchorage-independent growth) in HeLaHF cells, similar to that of p53 gene silencing, implying its tumor suppressor effect. However, the observed increased transformation potential by PHTS silencing appears to be due to an increased anchorage-independent proliferation rate rather than suppression of anoikis, unlike the effect of p53 silencing. p53 silencing did not affect PHTS gene expression, and vice versa, suggesting PHTS may function in a new and p53-independent tumor suppressor pathway. Furthermore, over-expression of PHTS in different cancer cell lines, in addition to HeLa, reduces cell growth likely via induced apoptosis, confirming the broad PHTS tumor suppressor properties.
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http://dx.doi.org/10.1016/j.yexcr.2005.12.006DOI Listing
April 2006

Genetic reprogramming of tumor cells by zinc finger transcription factors.

Proc Natl Acad Sci U S A 2005 Aug 4;102(33):11716-21. Epub 2005 Aug 4.

Department of Molecular Biology and The Skaggs Institute for Chemical Biology, La Jolla, CA 92037, USA.

Cancer arises by the accumulation of genetic alterations in DNA leading to aberrant gene transcription. Expression-profiling studies have correlated genomewide expression signatures with malignancy. However, functional analysis elucidating the contribution and synergy of genes in specific cancer cell phenotypes remains a formidable obstacle. Herein, we describe an alternative genetic approach for identification of genes involved in tumor progression by using a library of zinc finger artificial transcription factors (ATFs) and functional screening of tumor cells as a source of genetic plasticity and clonal selection. We isolated a six-zinc finger transcriptional activator (TF 20-VP, TF 20 containing the VP64 activator domain) that acts to reprogram a drug-sensitive, poorly invasive, and nonmetastatic cell line into a cell line with a drug-resistant, highly invasive, and metastatic phenotype. Differential expression profiles of cells expressing TF 20-VP followed by functional studies, both in vitro and in animal models, revealed that invasion and metastasis requires co-regulation of multiple target genes. Significantly, the E48 antigen, associated with poor metastasis-free survival in head and neck cancer, was identified as one specific target of TF 20-VP. We have shown phenotypic modulation of tumor cell behavior by E48 expression, including enhanced cell migration in vitro and tumor cell dissemination in vivo. This study demonstrates the use of ATFs to identify the group of genes that cooperate during tumor progression. By co-regulating multiple targets, ATFs can be used as master genetic switches to reprogram and modulate complex neoplastic phenotypes.
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http://dx.doi.org/10.1073/pnas.0501162102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1187960PMC
August 2005

Nuclear hormone receptor NR4A2 is involved in cell transformation and apoptosis.

Cancer Res 2004 Nov;64(22):8208-12

Immusol, Inc., San Diego, California 92121, USA.

HeLaHF cells are transformation revertants of cervical cancer HeLa cells and have lost anchorage-independent growth potential and tumorigenicity. Activation of tumor suppressor(s) was implicated previously in this transformation reversion. In this study, expression profiling analysis was carried out to identify potential oncogenes that are down-regulated in HeLaHF cells. We found that all three members of the NR4A1/Nur77/NGFIB orphan nuclear hormone receptor subfamily (NR4A1, NR4A2, and NR4A3) were down-regulated in the HeLaHF revertant. Small interfering RNA-mediated down-regulation of NR4A2 in HeLa cells, either transiently or stably, resulted in reduced anchorage-independent growth that was largely attributable to increased anoikis. Furthermore, down-regulation of NR4A2 as well as NR4A1 promoted intrinsic apoptosis. These phenotypes were also observed in several other experimental cancer cells, suggesting the observed apoptosis suppression is a more general property of NR4A2 and NR4A1. These phenotypes also suggest that the Nur77/NGFIB subfamily of orphan receptors exhibit certain oncogenic functionalities with regards to cell proliferation and apoptosis and could therefore be evaluated as potential cancer therapeutic targets.
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http://dx.doi.org/10.1158/0008-5472.CAN-04-2134DOI Listing
November 2004

A microarray-based, integrated approach to identify novel regulators of cancer drug response and apoptosis.

Oncogene 2002 Nov;21(54):8361-71

Oncology Research, Novartis Pharma AG, CH-4002 Basel, Switzerland.

DNA microarrays are powerful tools for the analysis of gene expression on a genomic scale. The importance of individual regulatory events for the process under study can however not be deduced unequivocally without additional experiments. We devised a strategy to identify central regulators of cancer drug responses by combining the results of microarray experiments with efficient methods for phenotypic testing of candidate genes. We exposed murine FL5.12 pro-B cells to cisplatin, camptothecin, methotrexate or paclitaxel, respectively and analysed the patterns of gene expression with cDNA microarrays. Drug-specific regulatory events as well as intersections between different apoptotic pathways, including previously studied responses to staurosporine and interleukin-3 (IL-3) deprivation, were identified. Genes shared by at least three pathways were chosen for further analysis. Ectopic expression of three such genes, TEAP, GP49B, and Lipin1 was found to have an anti-proliferative effect on pro-B cells. Interestingly, we identified hemoglobin alpha as a strong pro-apoptotic regulator. While hemoglobin-expressing cells were growing normally in the presence of IL-3, they displayed accelerated apoptosis with similar kinetics as Bax overexpressing cells upon IL-3 removal. The pro-apoptotic effect of hemoglobin was suppressed by Bcl-2 and was characterized by enhanced stimulation of caspase activity.
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http://dx.doi.org/10.1038/sj.onc.1206016DOI Listing
November 2002

Reorientation of mispositioned spindles in short astral microtubule mutant spc72Delta is dependent on spindle pole body outer plaque and Kar3 motor protein.

Mol Biol Cell 2002 Apr;13(4):1366-80

Lehrstuhl für Angewandte Mikrobiologie, Biozentrum, Universität Basel, CH-4056 Basel, Switzerland.

Nuclear migration and positioning in Saccharomyces cerevisiae depend on long astral microtubules emanating from the spindle pole bodies (SPBs). Herein, we show by in vivo fluorescence microscopy that cells lacking Spc72, the SPB receptor of the cytoplasmic gamma-tubulin complex, can only generate very short (<1 microm) and unstable astral microtubules. Consequently, nuclear migration to the bud neck and orientation of the anaphase spindle along the mother-bud axis are absent in these cells. However, SPC72 deletion is not lethal because elongated but misaligned spindles can frequently reorient in mother cells, permitting delayed but otherwise correct nuclear segregation. High-resolution time-lapse sequences revealed that this spindle reorientation was most likely accomplished by cortex interactions of the very short astral microtubules. In addition, a set of double mutants suggested that reorientation was dependent on the SPB outer plaque and the astral microtubule motor function of Kar3 but not Kip2/Kip3/Dhc1, or the cortex components Kar9/Num1. Our observations suggest that Spc72 is required for astral microtubule formation at the SPB half-bridge and for stabilization of astral microtubules at the SPB outer plaque. In addition, our data exclude involvement of Spc72 in spindle formation and elongation functions.
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http://dx.doi.org/10.1091/mbc.01-07-0338DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC102275PMC
April 2002