Development of a NanoBRET assay to validate inhibitors of Sirt2-mediated lysine deacetylation and defatty-acylation that block prostate cancer cell migration.

Sirtuin2 (Sirt2) with its NAD+-dependent deacetylase and defatty-acylase activities plays a central role in the regulation of specific cellular functions. Dysregulation of Sirt2 activity has been associated with the pathogenesis of many diseases, thus making Sirt2 a promising target for pharmaceutical intervention. Herein, we present new high affinity Sirt2 selective Sirtuin-Rearranging Ligands (SirReals) that inhibit both Sirt2-dependent deacetylation and defatty-acylation in vitro and in cells. We show that simultaneous inhibition of both Sirt2 activities results in strongly reduced levels of the oncoprotein c-Myc and an inhibition of cancer cell migration. Furthermore, we describe the development of a NanoBRET-based assay for Sirt2, thereby providing a method to study cellular target engagement for Sirt2 in a straightforward and accurately quantifiable manner. Applying this assay, we could confirm cellular Sirt2 binding of our new Sirt2 inhibitors and correlate their anticancer effects with their cellular target engagement.

[Ataxias and hereditary spastic paraplegias]. / Ataxien und hereditäre spastische Spinalparalysen.

Hereditary ataxias and spastic paraplegias are genetic disorders with age-dependent nearly complete penetrance. The mostly monogenetic etiology allows one to establish the diagnosis, study pathogenesis and to develop new causative therapeutic approaches for these diseases. Both the causative genes as well as the clinical presentation overlap considerably between hereditary ataxias and spastic paraplegias. This strongly argues towards a united classification for these two groups of diseases. Next generation sequencing technologies have greatly expanded the number of genes known to be causative for hereditary ataxias and spastic paraplegias and allow simultaneous time- and cost-effective diagnostic testing of > 200 genes. However, repeat expansions and large genomic deletions must be considered separately. Here, we suggest a pragmatic algorithm for genetic testing in hereditary ataxias and spastic paraplegias that we have developed in our specialized outpatient clinics. Detailed phenotyping remains crucial to interpret the multitude of genetic variants discovered by high throughput sequencing techniques. Despite recent technical advances, a substantial proportion of ataxia and spastic paraplegia families are still without a molecular diagnosis. Beside new and so far undetected ataxia and spasticity genes, unusual mutation types including noncoding variants and polygenic inheritance patterns may contribute. Because of these clinical, genetic, and technological challenges, patients with hereditary ataxias and spastic paraplegias should be referred to specialized centers offering research and clinical studies. This will also help to recruit representative patient cohorts for upcoming interventional trials.

PLA2G6 mutations associated with a continuous clinical spectrum from neuroaxonal dystrophy to hereditary spastic paraplegia.

PLA2G6-associated neurodegeneration (PLAN) and hereditary spastic paraplegia (HSP) are 2 groups of heterogeneous neurodegenerative diseases. In this study, we report PLA2G6 gene mutations in 3 families from Turkey, Morocco, and Romania. Two affected Turkish siblings presenting HSP adds the disease to PLAN phenotypes. They were homozygous for the PLA2G6 missense c.2239C>T, p.Arg747Trp variant and the ages of onset were 9 and 21. Parkinsonism, dystonia or cognitive decline were not the clinical elements in these patients contrary to the cases that has been previously reported with the same variant, however, iron accumulation was evident in their cranial magnetic resonance imaging. The Moroccan patient was homozygous for a novel missense c.1786C>T, p.Leu596Phe variant and the Romanian patient had 2 novel mutations; c.1898C>T, p.Ala633Val and c.1765_1768del, p.Ser589ThrfsTer76. Both of these patients conformed better to childhood onset PLAN with the age of onset at 4 and 7 years, respectively. Interestingly, all identified mutations were affecting the highly conserved patatin-like phospholipase domain of the PLA2G6 protein.

CYP2U1 mutations in two Iranian patients with activity induced dystonia, motor regression and spastic paraplegia.

Hereditary spastic paraplegia (HSP) is a heterogeneous condition characterized by progressive spasticity and weakness in the lower limbs. It is divided into two major groups, complicated and uncomplicated, based on the presence of additional features such as intellectual disability, ataxia, seizures, peripheral neuropathy and visual problems. SPG56 is an autosomal recessive form of HSP with complicated and uncomplicated manifestations, complicated being more common. CYP2U1 gene mutations have been identified as responsible for SPG56. Intellectual disability, dystonia, subclinical sensory motor neuropathy, pigmentary degenerative maculopathy, thin corpus callosum and periventricular white-matter hyperintensities were additional features noted in previous cases of SPG56. Here we identified two novel mutations in CYP2U1 in two unrelated patients by whole exome sequencing. Both patients had complicated HSP with activity-induced dystonia, suggesting dystonia as an additional finding in SPG56. Two out of 14 previously reported patients had dystonia, and the addition of our patients suggests dystonia in a quarter of SPG56 patients. Developmental regression has not been reported in SPG56 patients so far but both of our patients developed motor regression in infancy.

[Interdisciplinary and individualized therapy of prostate cancer : International prostate cancer symposium Bonn 2013 - challenges and targets]. / Interdisziplinäre und individualisierte Therapie des Prostatakarzinoms : Internationales Prostatakrebssymposium Bonn 2013 - Herausforderungen und Ziele.

Multimodal treatment of prostate cancer is based on specific staging via imaging, clinical parameters, tumor markers and histopathological grading. Risk-adapted therapy encompasses wait and see, active surveillance, surgical intervention, radiotherapy and hormone therapy. Some patients also need a combination of these treatment options. Even though clinical parameters guide the treatment plan, patient wishes and preferences are incorporated. Against this background leading basic research scientists, urologists, radiotherapists, epidemiologists and members of other associated disciplines discussed state of the art treatment concepts, innovative trial designs and translational research projects at the international meeting "Challenges and Chances in Prostate Cancer Research" organized by the German Cancer Aid (Deutsche Krebshilfe).

LSD1 controls metastasis of androgen-independent prostate cancer cells through PXN and LPAR6.

Lysine-specific demethylase 1 (LSD1) was shown to control gene expression and cell proliferation of androgen-dependent prostate cancer (PCa) cells, whereas the role of LSD1 in androgen-independent metastatic prostate cancer remains elusive. Here, we show that depletion of LSD1 leads to increased migration and invasion of androgen-independent PCa cells. Transcriptome and cistrome analyses reveal that LSD1 regulates expression of lysophosphatidic acid receptor 6 (LPAR6) and cytoskeletal genes including the focal adhesion adaptor protein paxillin (PXN). Enhanced LPAR6 signalling upon LSD1 depletion promotes migration with concomitant phosphorylation of PXN. In mice LPAR6 overexpression enhances, whereas knockdown of LPAR6 abolishes metastasis of androgen-independent PCa cells. Taken together, we uncover a novel mechanism of how LSD1 controls metastasis and identify LPAR6 as a promising therapeutic target to treat metastatic prostate cancer.

Leukodystrophies underlying cryptic spastic paraparesis: frequency and phenotype in 76 patients.

BACKGROUND AND PURPOSE: In chronic progressive spasticity of the legs many rare causes have to be considered, including leukodystrophies due to neurometabolic disorders. To determine the frequency of leukodystrophies and the phenotypic spectrum patients with cryptic spasticity of the legs were screened for underlying neurometabolic abnormalities. METHODS: Seventy-six index patients presenting with adult-onset lower limb spasticity of unknown cause consistent with autosomal recessive inheritance were included in this study. Screening included serum levels of very long chain fatty acids for X-linked adrenoleukodystrophy/adrenomyeloneuropathy and lysosomal enzyme activities in leukocytes for metachromatic leukodystrophy, GM1-gangliosidosis, Tay-Sachs, Sandhoff and Krabbe disease. If clinical evidence was indicative of other types of leukodystrophies, additional genetic testing was conducted. Clinical characterization included neurological and psychiatric features and magnetic resonance imaging. RESULTS: Basic screening detected one index patient with metachromatic leukodystrophy, two patients with Krabbe disease and four patients with adrenoleukodystrophy/adrenomyeloneuropathy. Additional genetic testing revealed one patient with vanishing white matter disease. These patients accounted for an overall share of 11% of leukodystrophies. One patient with Krabbe disease and three patients with adrenoleukodystrophy/adrenomyeloneuropathy presented with pure spasticity of the lower limbs, whilst one patient each with Krabbe disease, metachromatic leukodystrophy and adrenoleukodystrophy/adrenomyeloneuropathy showed additional complicating symptoms. CONCLUSIONS: Adult patients presenting with cryptic spasticity of the legs should be screened for underlying X-linked adrenoleukodystrophy/adrenomyeloneuropathy and lysosomal disorders, irrespective of the presence of additional complicating symptoms. Leukodystrophies may manifest as late as the sixth decade and hyperintensity of cerebral white matter on magnetic resonance FLAIR images is not obligatory.

Lysine-specific demethylase 1 restricts hematopoietic progenitor proliferation and is essential for terminal differentiation.

Lysine (K)-specific demethylase 1A (LSD1/KDM1A) has been identified as a potential therapeutic target in solid cancers and more recently in acute myeloid leukemia. However, the potential side effects of a LSD1-inhibitory therapy remain elusive. Here, we show, with a newly established conditional in vivo knockdown model, that LSD1 represents a central regulator of hematopoietic stem and progenitor cells. LSD1 knockdown (LSD1-kd) expanded progenitor numbers by enhancing their proliferative behavior. LSD1-kd led to an extensive expansion of granulomonocytic, erythroid and megakaryocytic progenitors. In contrast, terminal granulopoiesis, erythropoiesis and platelet production were severely inhibited. The only exception was monopoiesis, which was promoted by LSD1 deficiency. Importantly, we showed that peripheral blood granulocytopenia, monocytosis, anemia and thrombocytopenia were reversible after LSD1-kd termination. Extramedullary splenic hematopoiesis contributed to the phenotypic reversion, and progenitor populations remained expanded. LSD1-kd was associated with the upregulation of key hematopoietic genes, including Gfi1b, Hoxa9 and Meis1, which are known regulators of the HSC/progenitor compartment. We also demonstrated that LSD1-kd abrogated Gfi1b-negative autoregulation by crossing LSD1-kd with Gfi1b:GFP mice. Taken together, our findings distinguish LSD1 as a critical regulator of hematopoiesis and point to severe, but reversible, side effects of a LSD1-targeted therapy.

Factor XIII Val34Leu polymorphism is associated with increased factor XIII activation and decreased transcutaneous oxygen readings in patients with diabetic foot ulcers.

AIM: To investigate the relationship between the factor XIII Val34Leu polymorphism, plasma factor XIII activation and transcutaneous oxygen readings in patients with diabetic foot ulcers. Methods Ninety-two consecutive patients with Type diabetes and active foot ulcers were investigated. Plasma factor XIII activation was assessed by ELISA. Genetic polymorphism was detected using the ABI PRISM® SNaPshotTM Multiplex Kit. Results are expressed as median (minimum-maximum). Differences between groups were calculated by Mann-Whitney U-test or χ(2) -test where appropriate. A P-value < .05 was considered significant. RESULTS: e Val34Leu polymorphism was found in 50 subjects (54%) with 42 being heterozygous (Val/Leu) and eight being homozygous (Leu/Leu). The rate of plasma factor XIII activation was increased in patients with Val/Leu or Leu/Leu [Val/Leu or Leu/Leu 152 (55-283) % vs. Val/Val 103 (33-282) %; P < 0.0001]. Transcutaneous oxygen readings were lower in the Val/Leu or Leu/Leu group [Val/Leu or Leu/Leu 16 (0-58) mmHg vs. Val/Val 35 (1-65) mmHg; P = 0.008]. Similarly, plasma factor XIII activation negatively correlated with transcutaneous oxygen readings (r(2) = -0.314; P = 0.014). CONCLUSIONS: Val34Leu polymorphism is associated with increased plasma factor XIII activation and seems to be linked with impaired cutaneous microcirculation in patients with diabetic foot ulcers.

Disease severity affects quality of life of hereditary spastic paraplegia patients.

BACKGROUND AND PURPOSE: Hereditary spastic paraplegia (HSP) causes progressive gait disturbance because of degeneration of the corticospinal tract. To assess its impact on Health-Related Quality of Life (HRQoL), we analyzed the correlation of HRQoL with disease severity and clinical symptoms in HSP. METHODS: HRQoL was assessed by the Short-Form 36 (SF-36) Mental and Physical Component summary scores (MCS and PCS) in 143 German patients with HSP. Disease severity was assessed by the Spastic Paraplegia Rating Scale (SPRS) and landmarks of walking ability. Patients with 'pure' or 'complicated' HSP were compared. RESULTS: Higher SPRS scores indicating higher disease severity correlated significantly with lower PCS (r = -0.63; P < 0.0005) and MCS (r = -0.38; P < 0.0005) scores. MCS and PCS were reduced in patients with 'complicated' forms compared to 'pure' HSP and with decreasing walking ability. CONCLUSION: HRQoL is substantially impaired in patients with HSP and decreases with disease severity and the presence of 'complicating' symptoms. Patients are most affected by the physical restraints of their disease, but mental health is impaired as well. HRQoL is a valid parameter in HSP that should be considered in upcoming therapeutical trials.

Paroxysmal choreoathetosis/spasticity (DYT9) is caused by a GLUT1 defect.

OBJECTIVE: Mutations in SLC2A1, encoding the glucose transporter type 1 (GLUT1), cause a broad spectrum of neurologic disorders including classic GLUT1 deficiency syndrome, paroxysmal exercise-induced dyskinesia (PED, DYT18), and absence epilepsy. A large German/Dutch pedigree has formerly been described as paroxysmal choreoathetosis/spasticity (DYT9) and linked close to but not including the SLC2A1 locus on chromosome 1p. We tested whether 1) progressive spastic paraparesis, in addition to PED, as described in DYT9, and 2) autosomal dominant forms of hereditary spastic paraparesis (HSP) without PED are caused by SLC2A1 defects. METHODS: The German/Dutch family and an Australian monozygotic twin pair were clinically (re-)investigated, and 139 index cases with dominant or sporadic HSP in which relevant dominant genes were partially excluded were identified from databanks. SLC2A1 was sequenced in all cases in this observational study and the functional effects of identified sequence variations were tested in glucose uptake and protein expression assays. RESULTS: We identified causative mutations in SLC2A1 in both families, which were absent in 400 control chromosomes, cosegregated with the affection status, and decreased glucose uptake in functional assays. In the 139 index patients with HSP without paroxysmal dyskinesias, we only identified one sequence variation, which, however, neither decreased glucose uptake nor altered protein expression. CONCLUSIONS: This study shows that DYT9 and DYT18 are allelic disorders and enlarges the spectrum of GLUT1 phenotypes, now also including slowly progressive spastic paraparesis combined with PED. SLC2A1 mutations were excluded as a cause of HSP without PED in our cohort.

Amplicon-based high-throughput pooled sequencing identifies mutations in CYP7B1 and SPG7 in sporadic spastic paraplegia patients.

Hereditary spastic paraplegia (HSP) is a neurodegenerative disorder defined clinically by progressive lower limb spasticity and weakness. HSP is a genetically highly heterogeneous condition with at least 46 gene loci identified so far, involving X-linked, autosomal recessive (AR) and autosomal dominant inheritance. For correct diagnosis, molecular testing is essential because clinical parameters by themselves are not reliable to differentiate HSP forms. The purpose of this study was to establish amplicon-based high-throughput genotyping for AR-HSP. A sample of 187 index cases with apparently sporadic or recessive spastic paraplegia were analyzed by applying an array-based amplification strategy. Amplicon libraries of the CYP7B1-(SPG5) and SPG7-gene were generated followed by a pooled next-generation sequencing (NGS) approach. We identified three SPG5 and seven SPG7 patients. All had one homozygous or two heterozygous mutations. In total, 20 distinct mutations (CYP7B1,n = 4and SPG7,n = 16) including two novel CYP7B1 mutations (p.G51R and p.E211KfsX3) and eight novel SPG7 mutations (p.Leu8delinsLeuLeu, p.W29X, p.R139X, p.R247X, p.G344D, p.Leu346_Leu347ins11, p.R398X and p.R398Q) were detected by this comprehensive genetic testing. Our study illustrates how amplicon-based NGS can be used as an efficient tool to study genotypes and mutations in large patient cohorts and complex phenotypes.

A novel clinical syndrome revealing a deficiency of the muscarinic M3 receptor.

OBJECTIVES: No clinical disorders have been caused by dysfunction of any of the 5 subtypes (M1-M5) of muscarinic receptors. We present a patient with a novel clinical syndrome that we suggest results from a deficiency of the muscarinic M3 receptor. METHODS: We conducted a comprehensive workup of autonomic function. The patient's disorder was compared to the phenotypic features of male M3 knockout mice. M3 protein quantity was assessed by Western blot and radioligand binding in peripheral blood lymphocytes. Tests for autoantibodies and genetic abnormalities were performed. RESULTS: The disease pattern was characterized by disturbances in micturition, pupil constriction, body weight, and sudomotor function, with normal accommodation, gastrointestinal motility, salivation, and lacrimation, similar to features of male M3 knockout mice. M3 protein quantity was reduced. Genetic tests were unrevealing, but unspecific antinuclear antibodies were present. CONCLUSIONS: The presented clinical syndrome suggests a deficiency of the muscarinic M3 receptor. These results and future evaluation of patients with autonomic deficits may provide insights into the site and functional role of the muscarinic M3 receptor in humans.

Frequency and phenotype of SPG11 and SPG15 in complicated hereditary spastic paraplegia.

BACKGROUND: Hereditary spastic paraplegias (HSP) are clinically and genetically highly heterogeneous. Recently, two novel genes, SPG11 (spatacsin) and SPG15 (spastizin), associated with autosomal recessive HSP, were identified. Clinically, both are characterised by complicated HSP and a rather similar phenotype consisting of early onset spastic paraplegia, cognitive deficits, thin corpus callosum (TCC), peripheral neuropathy and mild cerebellar ataxia. OBJECTIVE: To compare the frequency of SPG11 and SPG15 in patients with early onset complicated HSP and to further characterise the phenotype of SPG11 and SPG15. RESULTS: A sample of 36 index patients with early onset complicated HSP and a family history compatible with autosomal recessive inheritance was collected and screened for mutations in SPG11 and SPG15. Overall frequency of SPG11 was 14% (5/36) but was considerably higher in patients with TCC (42%). One patient with mental retardation and thinning of the corpus callosum was compound heterozygous for two novel SPG15 mutations. Additionally, several new polymorphisms and sequence variants of unknown significance have been identified in the SPG15 gene. CONCLUSIONS: TCC seems to be the best phenotypic predictor for SPG11 as well as SPG15. No clinical features could discriminate between SPG11 and SPG15. Therefore, priority of genetic testing should be driven by mutation frequency that appears to be substantially higher in SPG11 than in SPG15.

Autosomal dominant spastic paraplegia with peripheral neuropathy maps to chr12q23-24.

OBJECTIVE: Hereditary spastic paraplegias (HSP) are genetically exceedingly heterogeneous. To date, 37 genetic loci for HSP have been described (SPG1-41), among them 16 loci for autosomal dominant disease. Notwithstanding, further genetic heterogeneity is to be expected in HSP, as various HSP families do not link to any of the known HSP loci. In this study, we aimed to map the disease locus in a German family segregating autosomal dominant complicated HSP. METHODS: A genome-wide linkage analysis was performed using the GeneChip Mapping 10Kv2.0 Xba Array containing 10,204 SNP markers. Suggestive loci were further analyzed by mapping of microsatellite markers. RESULTS: One locus on chromosome 12q23-24, termed SPG36, was confirmed by high density microsatellite fine mapping with a significant LOD score of 3.2. SPG36 is flanked by markers D12S318 and D12S79. Linkage to SPG36 was excluded in >20 additional autosomal dominant HSP families. Candidate genes were selected and sequenced. No disease-causing mutations were identified in the coding regions of ATXN2, HSPB8, IFT81, Myo1H, UBE3B, and VPS29. SPG36 is complicated by a sensory and motor neuropathy; it is therefore the eighth autosomal dominant subtype of complicated HSP. CONCLUSION: We report mapping of a new locus for autosomal dominant hereditary spastic paraplegia (HSP) (SPG36) on chromosome 12q23-24 in a German family with autosomal dominant HSP complicated by peripheral neuropathy.

SPG10 is a rare cause of spastic paraplegia in European families.

BACKGROUND: SPG10 is an autosomal dominant form of hereditary spastic paraplegia (HSP), which is caused by mutations in the neural kinesin heavy chain KIF5A gene, the neuronal motor of fast anterograde axonal transport. Only four mutations have been identified to date. OBJECTIVE: To determine the frequency of SPG10 in European families with HSP and to specify the SPG10 phenotype. PATIENTS AND METHODS: 80 index patients from families with autosomal dominant HSP were investigated for SPG10 mutations by direct sequencing of the KIF5A motor domain. Additionally, the whole gene was sequenced in 20 of these families. RESULTS: Three novel KIF5A mutations were detected in German families, including one missense mutation (c.759G>T, p.K253N), one in frame deletion (c.768_770delCAA, p.N256del) and one splice site mutation (c.217G>A). Onset of gait disturbance varied from infancy to 30 years of age. All patients presented clinically with pure HSP, but a subclinical sensory-motor neuropathy was detected by neurophysiology studies. CONCLUSIONS: SPG10 accounts for approximately 3% of European autosomal dominant HSP families. All mutations affect the motor domain of kinesin and thus most likely impair axonal transport. Clinically, SPG10 is characterised by spastic paraplegia with mostly subclinical peripheral neuropathy.

High frequency of partial SPAST deletions in autosomal dominant hereditary spastic paraplegia.

BACKGROUND: Hereditary spastic paraplegia (HSP) is a genetically heterogeneous neurodegenerative disease. The most frequent cause of autosomal dominant HSP is mutation of SPAST (SPG4 locus), but additional pedigrees remain mutation negative by conventional screening despite linkage to SPG4. OBJECTIVE: To determine the frequency of genomic copy number aberrations of SPAST in autosomal dominant HSP. METHODS: We developed and validated a multiplex ligation-dependent probe amplification assay targeting SPAST and SPG3A, another gene frequently involved in autosomal dominant HSP. In a multicenter study we subsequently investigated 65 index patients with autosomal dominant HSP, all of whom had previously been screened negative for SPAST mutations. Independent secondary samples, additional family members, and cDNA were analyzed to confirm positive findings. RESULTS: Aberrant MLPA profiles were identified in 12 cases (18%). They exclusively affect SPAST, represent deletions, segregate with the disease, and are largely pedigree specific. Internal SPAST deletions entail expression of correspondingly shortened transcripts, which vary in stability. Age at onset in SPAST deletion carriers does not differ from that associated with other SPAST mutations. CONCLUSIONS: Partial SPAST deletions, but not SPAST amplifications and SPG3A copy number aberrations, represent an underestimated cause of autosomal dominant hereditary spastic paraplegia. Partial SPAST deletions are likely to act via haploinsufficiency.

The Spastic Paraplegia Rating Scale (SPRS): a reliable and valid measure of disease severity.

OBJECTIVE: To develop and evaluate a clinical Spastic Paraplegia Rating Scale (SPRS) to measure disease severity and progression. METHODS: A 13-item scale was designed to rate functional impairment occurring in pure forms of spastic paraplegia (SP). Additional symptoms constituting a complicated form of SP are recorded in an inventory. Two independent patient cohorts were evaluated in a two-step validation procedure. RESULTS: Application of SPRS requires less than 15 minutes and does not require any special equipment, so it is suitable for an outpatient setting. Interrater agreement of SPRS was high (intraclass correlation coefficient = 0.99). Reliability was further supported by high internal consistency (Cronbach alpha = 0.91). SPRS values were almost normally distributed without apparent floor or ceiling effect. Construct validity was shown by high correlation of SPRS to Barthel Index and the International Cooperative Ataxia Rating Scale (convergent validity) and low correlation to Mini-Mental Status Examination (discriminant validity). CONCLUSION: The Spastic Paraplegia Rating Scale is a reliable and valid measure of disease severity.

Second primary tumor in anti-Ma1/2-positive paraneoplastic limbic encephalitis.

Memory loss can be a symptom of paraneoplastic limbic encephalitis (PLE) a neuropsychiatric disorder associated mostly with small-cell lung cancer and anti-Hu antibodies or with testicular tumors and anti-Ma2 antibodies. We present the case of a patient with temporal coincidence of beginning cognitive decline and diagnosis of a carcinoma of the prostate in whom we diagnosed anti-Ma1/Ma2-positive PLE. The tumor had been completely resected but memory impairment further deteriorated. As the effective treatment of the cancer is considered as the most efficient treatment of a paraneoplastic neurological syndrome (PNS) a second neoplasia was suspected in the patient. By the aid of whole body positron emission tomography with 18-fluorine fluoro-2-deoxy-glucose (FDG-PET) an adenocarcinoma of the cecum could be detected. Two months after surgery anti-Ma antibodies were negative. We conclude that a second neoplasia should be considered, if effective cancer treatment does not lead to improvement or stabilisation of a PNS. Tumor search should be exhaustive and include PET when conventional imaging fails to show a malignancy.

X-ray structure of the orphan nuclear receptor RORbeta ligand-binding domain in the active conformation.

The retinoic acid-related orphan receptor beta (RORbeta) exhibits a highly restricted neuronal-specific expression pattern in brain, retina and pineal gland. So far, neither a natural RORbeta target gene nor a functional ligand have been identified, and the physiological role of the receptor is not well understood. We present the crystal structure of the ligand-binding domain (LBD) of RORbeta containing a bound stearate ligand and complexed with a coactivator peptide. In the crystal, the monomeric LBD adopts the canonical agonist-bound form. The fatty acid ligand-coactivator peptide combined action stabilizes the transcriptionally active conformation. The large ligand-binding pocket is strictly hydrophobic on the AF-2 side and more polar on the beta-sheet side where the carboxylate group of the ligand binds. Site-directed mutagenesis experiments validate the significance of the present structure. Homology modeling of the other isotypes will help to design isotype-selective agonists and antagonists that can be used to characterize the physiological functions of RORs. In addition, our crystallization strategy can be extended to other orphan nuclear receptors, providing a powerful tool to delineate their functions.