Stability Increase of Phenolic Acid Decarboxylase by a Combination of Protein and Solvent Engineering Unlocks Applications at Elevated Temperatures

Enzymatic decarboxylation of biobased hydroxycinnamic acids gives access to phenolic styrenes for adhesive production. Phenolic acid decarboxylases are proficient enzymes that have been applied in aqueous systems, organic solvents, biphasic systems, and deep eutectic solvents, which makes stability a key feature. Stabilization of the enzyme would increase the total turnover number and thus reduce the energy consumption and waste accumulation associated with biocatalyst production. In this study, we used ancestral sequence reconstruction to generate thermostable decarboxylases. Investigation of a set of 16 ancestors resulted in the identification of a variant with an unfolding temperature of 78.1 °C and a half-life time of 45 h at 60 °C. Crystal structures were determined for three selected ancestors. Structural attributes were calculated to fit different regression models for predicting the thermal stability of variants that have not yet been experimentally explored. The models rely on hydrophobic clusters, salt bridges, hydrogen bonds, and surface properties and can identify more stable proteins out of a pool of candidates. Further stabilization was achieved by the application of mixtures of natural deep eutectic solvents and buffers. Our approach is a straightforward option for enhancing the industrial application of the decarboxylation process.

Mechanistic Insights into the Ene-Reductase-Catalyzed Promiscuous Reduction of Oximes to Amines

The biocatalytic reduction of the oxime moiety to the corresponding amine group has only recently been found to be a promiscuous activity of ene-reductases transforming α-oximo β-keto esters. However, the reaction pathway of this two-step reduction remained elusive. By studying the crystal structures of enzyme oxime complexes, analyzing molecular dynamics simulations, and investigating biocatalytic cascades and possible intermediates, we obtained evidence that the reaction proceeds via an imine intermediate and not via the hydroxylamine intermediate. The imine is reduced further by the ene-reductase to the amine product. Remarkably, a non-canonical tyrosine residue was found to contribute to the catalytic activity of the ene-reductase OPR3, protonating the hydroxyl group of the oxime in the first reduction step.

Structure of the Reductase Domain of a Fungal Carboxylic Acid Reductase and Its Substrate Scope in Thioester and Aldehyde Reduction

The synthesis of aldehydes from carboxylic acids has long been a challenge in chemistry. In contrast to the harsh chemically driven reduction, enzymes such as carboxylic acid reductases (CARs) are considered appealing biocatalysts for aldehyde production. Although structures of single- and didomains of microbial CARs have been reported, to date no full-length protein structure has been elucidated. In this study, we aimed to obtain structural and functional information regarding the reductase (R) domain of a CAR from the fungus Neurospora crassa (Nc). The NcCAR R-domain revealed activity for N-acetylcysteamine thioester (S-(2-acetamidoethyl) benzothioate), which mimics the phosphopantetheinylacyl-intermediate and can be anticipated as the minimal substrate for thioester reduction by CARs. The determined crystal structure of the NcCAR R-domain reveals a tunnel that putatively harbors the phosphopantetheinylacyl-intermediate, which is in good agreement with docking experiments performed with the minimal substrate. In vitro studies were performed with this highly purified R-domain and NADPH, demonstrating carbonyl reduction activity. The R-domain was able to accept not only a simple aromatic ketone but also benzaldehyde and octanal, which are typically considered to be the final product of carboxylic acid reduction by CAR. Also, the full-length NcCAR reduced aldehydes to primary alcohols. In conclusion, aldehyde overreduction can no longer be attributed exclusively to the host background.

Conversation analysis, psychopathology and subjective experience in patients with schizophrenia

Introduction

Patients with schizophrenia show severe difficulties in interpersonal communication, including impairments in conversation skills, like the turn-taking. To our knowledge, very few studies to date have taken into account conversation analysis in order to investigate turn-taking in schizophrenia patients.

Objectives

To investigate the conversational patterns in schizophrenia patients; to assess possible associations between dialogic features, abnormal subjective experiences and symptom dimensions.

Methods

Thirty-six patients with Schizophrenia underwent an interview, subsequently analyzed with an innovative semi-automatic analysis. Positive and Negative Syndrome Scale (PANSS) was adopted for the investigation of psychopathology and Examination of Anomalous Self Experience (EASE) for Self-Disorders.

Results

Dialogic exchanges are graphically represented in Figure 1. An inverse correlation was found between participant speaking time and PANSS negative symptoms score (r = -0.44, p value < 0.05; Figure 2), whereas no associations were found between conversational variables and PANSS positive or disorganization dimensions. Finally, a positive correlation was found between the EASE item “spazialization of thought” and average pause duration (r = 0.42, p value < 0.05).

Conclusions

The finding of a relationship between negative symptoms and conversational patterns suggest that conversational features in schizophrenia are expression of the “core” negative dimension of the disorder. The association with the phenomenon of thought spatialization seems to suggest that the disturbances of the stream of consciousness impact on natural dialogic interactions. Ultimately, conversation analysis seems a promising tool to study dialogic exchanges of patients with schizophrenia.

Disclosure

No significant relationships.

The catalytic machinery of the FAD-dependent AtBBE-like protein 15 for alcohol oxidation: Y193 and Y479 form a catalytic base, Q438 and R292 an alkoxide binding site

Monolignol oxidoreductases are members of the berberine bridge enzyme-like (BBE-like) protein family (pfam 08031) that oxidize monolignols to the corresponding aldehydes. They are FAD-dependent enzymes that exhibit the para-cresolmethylhydroxylase-topology, also known as vanillyl oxidase-topology. Recently, we have reported the structural and biochemical characterization of two monolignol oxidoreductases from Arabidopsis thaliana, AtBBE13 and AtBBE15. Now, we have conducted a comprehensive site directed mutagenesis study for AtBBE15, to expand our understanding of the catalytic mechanism of this enzyme class. Based on the kinetic properties of active site variants and molecular dynamics simulations, we propose a refined, structure-guided reaction mechanism for the family of monolignol oxidoreductases. Here, we propose that this reaction is facilitated stepwise by the deprotonation of the allylic alcohol and a subsequent hydride transfer from the Cα-atom of the alkoxide to the flavin. We describe an excessive hydrogen bond network that enables the catalytic mechanism of the enzyme. Within this network Tyr479 and Tyr193 act concertedly as active catalytic bases to facilitate the proton abstraction. Lys436 is indirectly involved in the deprotonation as this residue determines the position of Tyr193 via a cation-π interaction. The enzyme forms a hydrophilic cavity to accommodate the alkoxide intermediate and to stabilize the transition state from the alkoxide to the aldehyde. By means of molecular dynamics simulations, we have identified two different and distinct binding modes for the substrate in the alcohol and alkoxide state. The alcohol interacts with Tyr193 and Tyr479 while Arg292, Gln438 and Tyr193 form an alkoxide binding site to accommodate this intermediate. The pH-dependency of the activity of the active site variants revealed that the integrity of the alkoxide binding site is also crucial for the fine tuning of the pK_a of Tyr193 and Tyr479. Sequence alignments showed that key residues for the mechanism are highly conserved, indicating that our proposed mechanism is not only relevant for AtBBE15 but for the majority of BBE-like proteins.

Biocatalytic Enantioselective Oxidation of Sec-Allylic Alcohols with Flavin-Dependent Oxidases

The oxidation of allylic alcohols is challenging to perform in a chemo- as well as stereo-selective fashion at the expense of molecular oxygen using conventional chemical protocols. Here, we report the identification of a library of flavin-dependent oxidases including variants of the berberine bridge enzyme (BBE) analogue from Arabidopsis thaliana (AtBBE15) and the 5-(hydroxymethyl)furfural oxidase (HMFO) and its variants (V465T, V465S, V465T/W466H and V367R/W466F) for the enantioselective oxidation of sec-allylic alcohols. While primary and benzylic alcohols as well as certain sugars are well known to be transformed by flavin-dependent oxidases, sec-allylic alcohols have not been studied yet except in a single report. The model substrates investigated were oxidized enantioselectively in a kinetic resolution with an E-value of up to >200. For instance HMFO V465S/T oxidized the (S)-enantiomer of (E)-oct-3-en-2-ol (1 a) and (E)-4-phenylbut-3-en-2-ol with E>200 giving the remaining (R)-alcohol with ee>99% at 50% conversion. The enantioselectivity could be decreased if required by medium engineering by the addition of cosolvents (e. g. dimethyl sulfoxide).

Mobile laboratories: An innovative and efficient solution for radiological characterization of sites under or after decommissioning

During the operation and the decommissioning of a nuclear site the operator must assure the protection of the workers and the environment. It must furthermore identify and classify the various wastes, while optimizing the associated costs. At all stages of the decommissioning radiological measurements are performed to determine the initial situation, to monitor the demolition and clean-up, and to verify the final situation. Radiochemical analysis is crucial for the radiological evaluation process to optimize the clean-up operations and to the respect limits defined with the authorities. Even though these types of analysis are omnipresent in activities such as the exploitation, the monitoring, and the cleaning up of nuclear plants, some nuclear sites do not have their own radiochemical analysis laboratory. Mobile facilities can overcome this lack when nuclear facilities are dismantled, when contaminated sites are cleaned-up, or in a post-accident situation. The current operations for the characterization of radiological soils of CEA nuclear facilities, lead to a large increase of radiochemical analysis. To manage this high throughput of samples in a timely manner, the CEA has developed a new mobile laboratory for the clean-up of its soils, called SMaRT (Shelter for Monitoring and nucleAR chemisTry). This laboratory is dedicated to the preparation and the radiochemical analysis (alpha, beta, and gamma) of potentially contaminated samples. In this framework, CEA and Eichrom laboratories has signed a partnership agreement to extend the analytical capacities and bring on site optimized and validated methods for different problematic. Gamma-emitting radionuclides can usually be measured in situ as little or no sample preparation is required. Alpha and beta-emitting radionuclides are a different matter. Analytical chemistry laboratory facilities are required. Mobile and transportable laboratories equipped with the necessary tools can provide all that is needed. The main advantage of a mobile laboratory is its portability; the shelter can be placed in the vicinity of nuclear facilities under decommissioning, or of contaminated sites with infrastructures unsuitable for the reception and treatment of radioactive samples. Radiological analysis can then be performed without the disadvantages of radioactive material transport. This paper describes how this solution allows a fast response and control of costs, with a high analytical capacity.

CLA-supplemented diet accelerates experimental colorectal cancer by inducing TGF-β-producing macrophages and T cells

Conjugated linoleic acid (CLA) has been shown to activate the nuclear receptor PPAR-γ and modulate metabolic and immune functions. Despite the worldwide use of CLA dietary supplementation, strong scientific evidence for its proposed beneficial actions are missing. We found that CLA-supplemented diet reduced mucosal damage and inflammatory infiltrate in the dextran sodium sulfate (DSS)-induced colitis model. Conditional deletion of PPAR-γ in macrophages from mice supplemented with CLA diet resulted in loss of this protective effect of CLA, suggesting a PPAR-γ-dependent mechanism mediated by macrophages. However, CLA supplementation significantly worsened colorectal tumor formation induced by azoxymethane and DSS by inducing macrophage and T-cell-producing TGF-β via PPAR-γ activation. Accordingly, either macrophage-specific deletion of PPAR-γ or in vivo neutralization of latency-associated peptide (LAP, a membrane-bound TGF-β)-expressing cells abrogated the protumorigenic effect of CLA. Thus, the anti-inflammatory properties of CLA are associated with prevention of colitis but also with development of colorectal cancer.

Oxidative cyclization of N-methyl-dopa by a fungal flavoenzyme of the amine oxidase family

Flavin-dependent enzymes catalyze many oxidations, including formation of ring structures in natural products. The gene cluster for biosynthesis of fumisoquins, secondary metabolites structurally related to isoquinolines, in the filamentous fungus Aspergillus fumigatus harbors a gene that encodes a flavoprotein of the amine oxidase family, termed fsqB (fumisoquin biosynthesis gene B). This enzyme catalyzes an oxidative ring closure reaction that leads to the formation of isoquinoline products. This reaction is reminiscent of the oxidative cyclization reported for berberine bridge enzyme and tetrahydrocannabinol synthase. Despite these similarities, amine oxidases and berberine bridge enzyme–like enzymes possess distinct structural properties, prompting us to investigate the structure–function relationships of FsqB. Here, we report the recombinant production and purification of FsqB, elucidation of its crystal structure, and kinetic analysis employing five putative substrates. The crystal structure at 2.6 Å resolution revealed that FsqB is a member of the amine oxidase family with a covalently bound FAD cofactor. N-methyl-dopa was the best substrate for FsqB and was completely converted to the cyclic isoquinoline product. The absence of the meta-hydroxyl group, as e.g. in l-N-methyl-tyrosine, resulted in a 25-fold lower rate of reduction and the formation of the demethylated product l-tyrosine, instead of a cyclic product. Surprisingly, FsqB did not accept the d-stereoisomer of N-methyltyrosine, in contrast to N-methyl-dopa, for which both stereoisomers were oxidized with similar rates. On the basis of the crystal structure and docking calculations, we postulate a substrate-dependent population of distinct binding modes that rationalizes stereospecific oxidation in the FsqB active site.

The single berberine bridge enzyme homolog of Physcomitrella patens is a cellobiose oxidase

The berberine bridge enzyme from the California poppy Eschscholzia californica (EcBBE) catalyzes the oxidative cyclization of (S)‐reticuline to (S)‐scoulerine, that is, the formation of the berberine bridge in the biosynthesis of benzylisoquinoline alkaloids. Interestingly, a large number of BBE‐like genes have been identified in plants that lack alkaloid biosynthesis. This finding raised the question of the primordial role of BBE in the plant kingdom, which prompted us to investigate the closest relative of EcBBE in Physcomitrella patens (PpBBE1), the most basal plant harboring a BBE‐like gene. Here, we report the biochemical, structural, and in vivo characterization of PpBBE1. Our studies revealed that PpBBE1 is structurally and biochemically very similar to EcBBE. In contrast to EcBBE, we found that PpBBE1 catalyzes the oxidation of the disaccharide cellobiose to the corresponding lactone, that is, PpBBE1 is a cellobiose oxidase. The enzymatic reaction mechanism was characterized by a structure‐guided mutagenesis approach that enabled us to assign a catalytic role to amino acid residues in the active site of PpBBE1. In vivo experiments revealed the highest level of PpBBE1 expression in chloronema, the earliest stage of the plant's life cycle, where carbon metabolism is strongly upregulated. It was also shown that the enzyme is secreted to the extracellular space, where it may be involved in later steps of cellulose degradation, thereby allowing the moss to make use of cellulose for energy production. Overall, our results suggest that the primordial role of BBE‐like enzymes in plants revolved around primary metabolic reactions in carbohydrate utilization.

Database

Structural data are available in the PDB under the accession numbers 6EO4 and 6EO5.

Abstract P4-22-09: A phase 2 open label study of everolimus in combination with endocrine therapy in resistant hormone receptor-positive HER2-negative advanced breast cancer

Background: Therapies targeting estrogen receptor (ER) signaling are standard for patients (pts) with hormone receptor positive (HR+) (ER and/or progesterone receptor [PR] positive) metastatic breast cancer (MBC). Dysregulation of the mammalian target of rapamycin (mTOR) pathway has been associated with endocrine therapy (ET) resistance. BOLERO-2 demonstrated that the addition of the mTOR inhibitor, everolimus (EVE), to exemestane doubled the PFS in HR+ HER2- MBC pts who previously progressed on nonsteroidal aromatase inhibitor therapy.The premise of this phase 2 trial in HR+ MBC is that the addition of EVE to the last ET on which the disease progressed may restore sensitivity to ET and extend the benefit of the anti-estrogen therapy.

Methods: Pts ≥18 yrs with HR+, HER2- unresectable, locally recurrent, or MBC refractory to ET in either the adjuvant or advanced/metastatic setting. 0-1 chemotherapy (chemo) regimens for MBC were permitted. Post-/ pre-/peri-menopausal women were eligible with ovarian function suppression permitted. Additional eligibility requirements include: no prior mTOR inhibitor therapy, measurable or evaluable disease, ECOG ≤2, adequate bone marrow and organ function. EVE (10 mg PO daily) was administered on a 4-wk cycle in combination with the same dose and schedule of the last ET to which their disease became resistant. Disease assessments were performed every 2 cycles and treatment continued until disease progression or unacceptable toxicity. Blood samples and archival tumor were collected respectively for the VeriStrat Assay and for the Foundation One molecular profiling platform.

Results: 48 pts were enrolled; data from 26 pts is presented. Median age 63.5 yrs (range, 36-81) with 46% ≥ 65 yrs. 14 (54%) pts had received chemo in the adjuvant setting, 9 pts (35%) received chemo for MBC, and 4 pts (15%) received chemo in both settings. All pts had at least 1 prior hormonal therapy; 9 pts received ≥ 3 hormonal agents. EVE was combined with tamoxifen (27%), AIs (61%), and fulvestrant (12%). Median time on treatment was 18.6 wks (range 1-48.9 weeks). 5 pts (19%) remain on treatment and 21 (81%) have discontinued therapy due to: disease progression - 17, toxicity -2, and other causes - 2. 23 pts were evaluable for response. 1 pt on fulvestrant plus EVE had a PR and 18 pts (78%) had SD as best response, with SD &gt; 6 mos in 7 pts, for a clinical benefit rate (CR+PR+ SD ≥ 6 months) of 35%. With a median follow up of 11 mos (range 2-16 mos), the median PFS was 6.6 months (range 3.6-9.4); the median OS has not been reached. Treatment-related adverse events consisted mostly of stomatitis, rash and fatigue with few G3 events: stomatitis 3 pts, rash 2 pts, and 1 each of fatigue, edema, and neutropenia. G1 pneumonitis was present in 2 pts. There were no G4 events or treatment related deaths.

Conclusions: In HR+ HER2- advanced/MBC patients who progressed on prior ET, the addition of EVE to the ET to which their disease became resistant, resulted in 1 PR and 7 pts with SD &gt; 6 mos. The results of the full study population will be presented. Modulation of the mTOR/AKT/PI3K pathway with EVE may extend the benefit of ET, even after tumor progression on ET alone.

Citation Format: Yardley DA, Blakely L, Hemphill B, Joseph M, Liggett W, Daniel B, Castrellon A, Shastry M, Finney L, DeBusk L, Hainsworth JD, Burris III HA. A phase 2 open label study of everolimus in combination with endocrine therapy in resistant hormone receptor-positive HER2-negative advanced breast cancer [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 P4-22-09.

Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory

Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170  TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.

Fatty acid-related modulations of membrane fluidity in cells: detection and implications

Metabolic homeostasis of fatty acids is complex and well-regulated in all organisms. The biosynthesis of saturated fatty acids (SFA) in mammals provides substrates for β-oxidation and ATP production. Monounsaturated fatty acids (MUFA) are products of desaturases that introduce a methylene group in cis geometry in SFA. Polyunsaturated fatty acids (n-6 and n-3 PUFA) are products of elongation and desaturation of the essential linoleic acid and α-linolenic acid, respectively. The liver processes dietary fatty acids and exports them in lipoproteins for distribution and storage in peripheral tissues. The three types of fatty acids are integrated in membrane phospholipids and determine their biophysical properties and functions. This study was aimed at investigating effects of fatty acids on membrane biophysical properties under varying nutritional and pathological conditions, by integrating lipidomic analysis of membrane phospholipids with functional two-photon microscopy (fTPM) of cellular membranes. This approach was applied to two case studies: first, pancreatic beta-cells, to investigate hormetic and detrimental effects of lipids. Second, red blood cells extracted from a genetic mouse model defective in lipoproteins, to understand the role of lipids in hepatic diseases and metabolic syndrome and their effect on circulating cells.

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst)  MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

Solid-phase synthesis of Rhodamine-110 fluorogenic substrates and their application in forensic analysis

A novel synthesis demonstrates the rapid and efficient preparation of fluorogenic substrates containing Rhodamine-110 fluorophores for the detection of biological evidence.

Search for patterns by combining cosmic-ray energy and arrival directions at the Pierre Auger Observatory

Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with [Formula: see text] eV by analyzing cosmic rays with energies above [Formula: see text] eV arriving within an angular separation of approximately 15[Formula: see text]. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources.

Oxidation of Monolignols by Members of the Berberine Bridge Enzyme Family Suggests a Role in Plant Cell Wall Metabolism

Plant genomes contain a large number of genes encoding for berberine bridge enzyme (BBE)-like enzymes. Despite the widespread occurrence and abundance of this protein family in the plant kingdom, the biochemical function remains largely unexplored. In this study, we have expressed two members of the BBE-like enzyme family from Arabidopsis thaliana in the host organism Komagataella pastoris. The two proteins, termed AtBBE-like 13 and AtBBE-like 15, were purified, and their catalytic properties were determined. In addition, AtBBE-like 15 was crystallized and structurally characterized by x-ray crystallography. Here, we show that the enzymes catalyze the oxidation of aromatic allylic alcohols, such as coumaryl, sinapyl, and coniferyl alcohol, to the corresponding aldehydes and that AtBBE-like 15 adopts the same fold as vanillyl alcohol oxidase as reported previously for berberine bridge enzyme and other FAD-dependent oxidoreductases. Further analysis of the substrate range identified coniferin, the glycosylated storage form of coniferyl alcohol, as a substrate of the enzymes, whereas other glycosylated monolignols were rather poor substrates. A detailed analysis of the motifs present in the active sites of the BBE-like enzymes in A. thaliana suggested that 14 out of 28 members of the family might catalyze similar reactions. Based on these findings, we propose a novel role of BBE-like enzymes in monolignol metabolism that was previously not recognized for this enzyme family.

Investigations on diffusion limitations of biocatalyzed reactions in amphiphilic polymer conetworks in organic solvents

The use of enzymes as biocatalysts in organic media is an important issue in modern white biotechnology. However, their low activity and stability in those media often limits their full-scale application. Amphiphilic polymer conetworks (APCNs) have been shown to greatly activate entrapped enzymes in organic solvents. Since these nanostructured materials are not porous, the bioactivity of the conetworks is strongly limited by diffusion of substrate and product. The present manuscript describes two different APCNs as nanostructured microparticles, which showed greatly increased activities of entrapped enzymes compared to those of the already activating membranes and larger particles. We demonstrated this on the example of APCN particles based on PHEA-l-PDMS loaded with α-Chymotrypsin, which resulted in an up to 28,000-fold higher activity of the enzyme compared to the enzyme powder. Furthermore, lipase from Rhizomucor miehei entrapped in particles based on PHEA-l-PEtOx was tested in n-heptane, chloroform, and substrate. Specific activities in smaller particles were 10- to 100-fold higher in comparison to the native enzyme. The carrier activity of PHEA-l-PEtOx microparticles was tenfold higher with some 25-50-fold lower enzyme content compared to a commercial product.

Abstract P5-20-10: Panitumumab, Gemcitabine and Carboplatin in Triple-Negative Metastatic Breast Cancer: Preliminary Results of a Phase II Trial of the Sarah Cannon Research Institute

Background: Triple-negative breast cancer (TNBC) is a poor prognosis subtype with treatment limited to chemotherapy. Over expression of epidermal growth factor receptor (EGFR) occurs in up to 70% of TNBC providing a potential targetable receptor for treatment. Panitumumab is an approved fully human, IgG2 monoclonal anti-EGFR antibody that inhibits intracellular growth signals dependent on receptor activation. The gemcitabine/platinum combination has demonstrated activity in metastatic as well as TNBC at various schedules and doses. We therefore investigated the efficacy and safety of panitumumab in combination with gemcitabine and carboplatin in patients (pts) with TNBC.

Methods: Eligibility criteria included: females with metastatic TNBC, 0–1 prior chemotherapy regimen for metastatic disease, ECOG PS 0–1, no brain metastases, no previous EGFR inhibitors and adequate organ function. All pts received gemcitabine 1500 mg/m2 IV, carboplatin AUC = 2.5 IV, and panitumumab 6 mg/kg IV every 2 weeks. A prophylactic skin regimen consisting of moisturizer, sunscreen and topical steroid was to be used 24 hours prior to study treatment and continued until panitumumab was discontinued. Pts were restaged after 3 treatment cycles and continued treatment until unacceptable toxicity or disease progression. If treatment benefit was demonstrated, and pts were experiencing toxicity or intolerance to gemcitabine, carboplatin or both, pts were allowed to discontinue either one or both agents and continue study treatment with panitumumab as a single agent or in combination. The primary endpoint of this study is progression free survival (PFS) with accrual of 70 pts necessary to detect an improvement in median PFS from 3.6 to 5.4 months (80% power, 10% level of significance).

Results: Between May 2010 and May 2012, 61 patients were enrolled with an accrual goal of 70 pts. This analysis is based on 47 pts. Pt characteristics include: median age 56, prior hormonal therapy 4%, no prior chemotherapy for metastatic disease in 87% (28% de novo stage IV), 1 prior chemotherapy for metastatic disease in 13%. Sites of metastatic disease included local regional/lymph nodes 70%, lung 57%, liver 32%, bone 26%, and others 23%. Best response to treatment was as follows: CR − 1 (2%), PR − 14 (30%), SD − 20 (43%), PD − 11 (23%), UE − 1 (2%). As 1st line TNBC therapy, the ORR was 34%. The most common grade 3/4 heme toxicities were neutropenia − 12 (25%), leucopenia − 7 (15%), anemia − 3 (6%) and thrombocytopenia − 2 (4%). Grade 3/4 non-hematologic toxicities were rash − 4 (9% with 1 grade 4), fatigue − 3 (6%) and DVT − 3 (6%). Grade 1 and 2 rash was present in 19 and 9 pts respectively. Archival tumor tissue was collected for correlative biomarker analysis to include PI3KCA, p53, PTEN, EGFR, and K-ras status.

Conclusions: The addition of panitumumab to gemcitabine and carboplatin in metastatic TNBC was active with an ORR of 32%. No new safety signals were identified and treatment was generally well tolerated with easily manageable toxicity. Full study results and correlative biomarker assessments will be reported.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-20-10.

Correlation of SPARC, ER, PR, and HER2 tumor with progression-free survival from a phase II neoadjuvant trial of gemcitabine, epirubicin, and nab-paclitaxel

618

Background: Neoadjuvant combinations of gemcitabine (G), anthracyclines and taxanes have demonstrated substantial activity with pCR rates of 20–25%. Secreted protein acidic rich in cysteine (SPARC) is an albumin binding protein that mediates intratumoral accumulation of nab-paclitaxel (nab-P) via a SPARC-albumin binding activity and is a poor prognostic factor for survival. This study was designed to evaluate the feasibility and safety of a biweekly schedule of neoadjuvant nab paclitaxel (nab-P) with G and epirubicin (E) with SPARC tumor assessments performed in consenting patients (pts). Methods: Eligibility: Clinical T1c-T4d and/or N0–3, M0 breast cancer (T1N0M0 excluded), normal LVEF. ER/PR/HER-2 obtained for all pts. Treatment: neoadjuvant G 2,000 mg/m2, E 50 mg/m2, and nab-P 175 mg/m2 q14 days x 6 cycles followed by surgery. Post operative therapy: G 2,000 mg/m2 and nab-P 220 mg/m2 q14 days x 4 cycles. Myeloid growth factors were mandated with all cycles. Two different antibody reagents were used to probe for SPARC expression of tumoral SPARC and stromal SPARC; level 3 immunohistochemical (IHC) SPARC staining was considered positive. Results: 123 pts enrolled. Pathologic responses are available for 112 pts with 11 unevaluable. 82 pts consented to SPARC tumor testing. Median age 51 (29–72). Median tumor size 4.5 cm. 42% ER-/PR -. 55% clinical T3/T4 and 66% node positive. Pathologic complete responses (pCR) were noted in 22 pts (18%) with PRs in 84 pts (68%), and 6 SD (5%). SPARC IHC staining was available in 77 tumor samples; SPARC positivity was noted in 89% of evaluated tumors achieving pCR. Triple negative, ER negative or PR negative tumors were associated with worse PFS. SPARC + tumors showed a trend to improved PFS that was strongly associated with tumoral SPARC but not stromal SPARC. Conclusions: Dose dense neoadjuvant G, E, and nab-P is active and well tolerated with a favorable pCR rate of 20%. ER neg, PR neg, and triple negative tumors were associated with worse PFS. Despite literature reports of SPARC positivity associated with poor prognosis, SPARC+ tumors in this study showed a high concordance with tumor response and a trend to improved PFS with tumoral SPARC.

[Table: see text]

Characterization of triple-negative breast cancer utilizing microarray-based gene-expression profiling

e22014

Background: Triple-negative breast cancer (TNBC) is characterized by lack of expression of estrogen receptor (ER), progesterone receptor (PR) and HER-2. This makes it one of the most challenging subgroups for clinical decision-making. Methods: We analyzed gene-expression profiles of 200 node-negative breast cancer patients utilizing the Affymetrix HG-U133A array. After performing an unsupervised hierarchical cluster analysis using 2579 genes selected for variable expression within our dataset, we constructed metagenes for five dominant cluster (basal-like, luminal, proliferation, T-cell, B-cell). The interrelation of the median expression of these metagenes between TNBC and those cancer specimens expressing at least one of those receptors was analysed with the Wilcoxon-Mann-Whitney test. An intrinsic gene list was used to define basal-like breast cancer (BLBC). Sensitivity and specificity of TNBC to correctly classify BLBC was calculated. Metastasis-free survival (MFS) at 5 years was calculated according to Kaplan Meier. Results: Of the 200 node-negative breast cancer patients, 33 (16.5%) were triple-negative and 20 (10%) basal-like. Sensitivity of TNBC to correctly predict BLBC was 100%, specificity was 93.1%. TNBC showed an overexpression of the basal-like metagene (P=7.905e-13), an inverse relation with the luminal metagene (p=1.151e-12) and had higher proliferation and higher expression of T-cell (P=6.316e-5) and B-cell (P=3.551e-6) metagene. A higher expression of the B-cell metagene was associated with longer MFS in both TNBC (P=0.048) and BLBC (P=0.041). Conclusions: Characterization of TNBC reveals marked differences in gene-expression. Overexpression of mRNA transcripts related to the humoral immune system might serve as a protective factor in this particular subgroup.

No significant financial relationships to disclose.

Preliminary progression free survival and SPARC tumor correlatives from a phase II neoadjuvant trial of gemcitabine, epirubicin, and nab paclitaxel

Abstract #5116

Background: Neoadjuvant combinations of gemcitabine (G), anthracyclines and taxanes have demonstrated significant activity with pCR rates of 20-25% albeit with significant myelosuppression. Secreted protein acidic rich in cysteine (SPARC) is an albumin binding protein that mediates intratumoral accumulation of nab-paclitaxel (nab-P) via a SPARC-albumin specific binding activity. This study was designed to evaluate a biweekly schedule of neoadjuvant nab paclitaxel (nab-P) with gemcitabine and epirubicin (E). SPARC tumor assessments were performed in consenting patients (pts) with subsequent pathologic and survival correlatives.&#x2028; Methods: Eligibility: Clinical T1c-T4d and/or N0-3, M0 breast cancer (T1N0M0 excluded), ECOG PS 0-2, normal LVEF. ER/PR/HER2 obtained for all pts. Treatment: 6 cycles neoadjuvant G 2000 mg/m2, E 50 mg/m2, and nab-P 175 mg/m2 q14 days followed by surgery. Post operative therapy: 4 cycles G 2000 mg/m2 and nab-P 220 mg/m2 q14 days. Myeloid growth factors were mandated with all cycles. 2 antibody reagents were used to probe for SPARC expressions. For this study, level 3 immunohistochemical (IHC) SPARC staining was considered positive. Results: 123 pts have enrolled with pathologic responses available for 106. 82 pts consented to SPARC testing. Median age 51 (29-72). Median tumor size 4.5 cm. Histology: 81% ductal, 10% lobular, 9% other. 42% ER and PR negative. 55% clinical T3/T4 and 66% lymph node positive at presentation. G3/4 toxicity present in &gt;5% of pts: neutropenia 16% (febrile neutropenia 1 pt), thrombocytopenia 9% with arthralgias 11%, fatigue 10%, and infection 7%. 20 pts did not complete study treatment for the following reasons: disease progression 7, toxicity 3, pt/MD request 5, and other 5. pCR was noted in 23 pts (22%) with PRs in 76 pts (71%), and 6 SD. SPARC IHC staining was available for 76 tumors. SPARC level 3 IHC staining was noted in 65 tumors (86%); 65% were associated with a PR or pCR. Median PFS was 23 months and overall survival at 24 months is 77%. Pts who relapsed ≤16 months from diagnosis were more likely to be triple negative (p = 0.04), or ER negative (p = 0.001), or PR negative (p = 0.0006). Conclusions: Neoadjuvant dose dense GEA is active and better tolerated than other gemcitabine/anthracycline/taxane combinations. The pCR rate of 22% compares favorably with other comparable neoadjuvant regimens albeit with minimal toxicity. Pts with early relapse defined as ≤16 months from diagnosis were more likely to demonstrate a triple negative phenotype or demonstrate estrogen or progesterone receptor negativity. SPARC tumor correlatives with progression free and overall survival are on ongoing and will be presented.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5116.

Correlation of contrast-enhanced MR images with the histopathology of minimally invasive thermal and cryoablation cancer treatments in normal dog prostates

Magnetic Resonance Imaging (MRI) is a promising tool for visualizing the delivery of minimally invasive cancer treatments such as high intensity ultrasound (HUS) and cryoablation. We use an acute dog prostate model to correlate lesion histopathology with contrast-enhanced (CE) T1 weighted MR images, to aid the radiologists in real time interpretation of in vivo lesion boundaries and pre-existing lesions. Following thermal or cryo treatments, prostate glands are removed, sliced, stained with the vital dye triphenyl tetrazolium chloride, photographed, fixed and processed in oversized blocks for routine microscopy. Slides are scanned by Trestle Corporation at .32 microns/pixel resolution, the various lesions traced using annotation software, and digital images compared to CE MR images. Histologically, HUS results in discrete lesions characterized by a "heat-fixed" zone, in which glands subjected to the highest temperatures are minimally altered, surrounded by a rim or "transition zone" composed of severely fragmented, necrotic glands, interstitial edema and vascular congestion. The "heat-fixed" zone is non-enhancing on CE MRI while the "transition zone" appears as a bright, enhancing rim. Likewise, the CE MR images for cryo lesions appear similar to thermally induced lesions, yet the histopathology is significantly different. Glands subjected to prolonged freezing appear totally disrupted, coagulated and hemorrhagic, while less intensely frozen glands along the lesion edge are partially fragmented and contain apoptotic cells. In conclusion, thermal and cryo-induced lesions, as well as certain pre-existing lesions (cystic hyperplasia - non-enhancing, chronic prostatitis - enhancing) have particular MRI profiles, useful for treatment and diagnostic purposes.

Operationalizing the concept of resilience in child neglect: case study research

BACKGROUND

There is a considerable amount of interest in resilience as a concept for child care and protection practice. This paper describes an exploratory project that drew on a set of case studies to explore the extent to which the concept of resilience can be operationalized for use with neglected children in the context of statutory social work.

METHOD

The study was carried out within a local authority in Scotland and focused on the value of the concept as an aid to assessment and planning. The study built on a published workbook that provides a structure for the assessment of potential areas of resilience and gives detailed suggestions for intervention in six domains of a child's life. Eight neglected children aged between five and 11 were recruited. Six training days on the concept were held. Questionnaires were used to gather information about the theoretical frameworks already being used. At the end of the study, semi-structured interviews were carried out with the social workers about the value of the concept. Assessment reports completed before and after the training were analysed.

RESULTS

Findings indicated that participants were familiar with the concept of resilience and that the training helped enhance their understanding of the concept. Training assisted with the provision of a more structured approach to assessment and planning. Respondents reported that the approach enhanced their knowledge of the child and they were able to identify areas for development in the six domains.

CONCLUSION

The study indicated that the concept of resilience can be operationalized for use with neglected children. Further, the case studies raised the issue of the extent to which the need for a secure base underpins other domains. The domain of positive values was also highlighted as an important area for further exploration.

Mapping of the prostate in endorectal coil-based MRI/MRSI and CT: A deformable registration and validation study

The endorectal coil is being increasingly used in magnetic resonance imaging (MRI) and MR spectroscopic imaging (MRSI) to obtain anatomic and metabolic images of the prostate with high signal-to-noise ratio (SNR). In practice, however, the use of endorectal probe inevitably distorts the prostate and other soft tissue organs, making the analysis and the use of the acquired image data in treatment planning difficult. The purpose of this work is to develop a deformable image registration algorithm to map the MRI/MRSI information obtained using an endorectal probe onto CT images and to verify the accuracy of the registration by phantom and patient studies. A mapping procedure involved using a thin plate spline (TPS) transformation was implemented to establish voxel-to-voxel correspondence between a reference image and a floating image with deformation. An elastic phantom with a number of implanted fiducial markers was designed for the validation of the quality of the registration. Radiographic images of the phantom were obtained before and after a series of intentionally introduced distortions. After mapping the distorted phantom to the original one, the displacements of the implanted markers were measured with respect to their ideal positions and the mean error was calculated. In patient studies, CT images of three prostate patients were acquired, followed by 3 Tesla (3 T) MR images with a rigid endorectal coil. Registration quality was estimated by the centroid position displacement and image coincidence index (CI). Phantom and patient studies show that TPS-based registration has achieved significantly higher accuracy than the previously reported method based on a rigid-body transformation and scaling. The technique should be useful to map the MR spectroscopic dataset acquired with ER probe onto the treatment planning CT dataset to guide radiotherapy planning.