Preclinical Characterization of AZD9574, a Blood-Brain Barrier Penetrant Inhibitor of PARP1

PURPOSE

We evaluated the properties and activity of AZD9574, a blood-brain barrier (BBB) penetrant selective inhibitor of PARP1, and assessed its efficacy and safety alone and in combination with temozolomide (TMZ) in preclinical models.

EXPERIMENTAL DESIGN

AZD9574 was interrogated in vitro for selectivity, PARylation inhibition, PARP-DNA trapping, the ability to cross the BBB, and the potential to inhibit cancer cell proliferation. In vivo efficacy was determined using subcutaneous as well as intracranial mouse xenograft models. Mouse, rat, and monkey were used to assess AZD9574 BBB penetration and rat models were used to evaluate potential hematotoxicity for AZD9574 monotherapy and the TMZ combination.

RESULTS

AZD9574 demonstrated PARP1-selectivity in fluorescence anisotropy, PARylation, and PARP-DNA trapping assays and in vivo experiments demonstrated BBB penetration. AZD9574 showed potent single agent efficacy in preclinical models with homologous recombination repair deficiency in vitro and in vivo. In an O6-methylguanine-DNA methyltransferase (MGMT)-methylated orthotopic glioma model, AZD9574 in combination with TMZ was superior in extending the survival of tumor-bearing mice compared with TMZ alone.

CONCLUSIONS

The combination of three key features-PARP1 selectivity, PARP1 trapping profile, and high central nervous system penetration in a single molecule-supports the development of AZD9574 as the best-in-class PARP inhibitor for the treatment of primary and secondary brain tumors. As documented by in vitro and in vivo studies, AZD9574 shows robust anticancer efficacy as a single agent as well as in combination with TMZ. AZD9574 is currently in a phase I trial (NCT05417594). See related commentary by Lynce and Lin, p. 1217.

Direct activation of KCC2 arrests benzodiazepine refractory status epilepticus and limits the subsequent neuronal injury in mice

Hyperpolarizing GABA_AR currents, the unitary events that underlie synaptic inhibition, are dependent upon efficient Cl^- extrusion, a process that is facilitated by the neuronal specific K⁺/Cl^- co-transporter KCC2. Its activity is also a determinant of the anticonvulsant efficacy of the canonical GABA_AR-positive allosteric: benzodiazepines (BDZs). Compromised KCC2 activity is implicated in the pathophysiology of status epilepticus (SE), a medical emergency that rapidly becomes refractory to BDZ (BDZ-RSE). Here, we have identified small molecules that directly bind to and activate KCC2, which leads to reduced neuronal Cl^- accumulation and excitability. KCC2 activation does not induce any overt effects on behavior but prevents the development of and terminates ongoing BDZ-RSE. In addition, KCC2 activation reduces neuronal cell death following BDZ-RSE. Collectively, these findings demonstrate that KCC2 activation is a promising strategy to terminate BDZ-resistant seizures and limit the associated neuronal injury.

DDDR-01. AZD9574 IS A NOVEL, BRAIN PENETRANT PARP-1 SELECTIVE INHIBITOR WITH ACTIVITY IN AN INTRACRANIAL XENOGRAFT MODEL OF TRIPLE NEGATIVE BREAST CARCINOMA WITH HOMOLOGOUS RECOMBINATION REPAIR DEFICIENCY

The Poly (ADP-ribose) polymerase (PARP) family has numerous essential functions in cellular processes such as transcription, chromatin remodelling, DNA damage response and repair as well as apoptosis. PARP inhibition blocks base excision repair and results in conversion of SSBs to DNA double-strand break (DSBs), the most deleterious form of DNA damage. DSBs can be repaired by homologous recombination repair (HRR) or non-homologous end joining (NHEJ). The physiological importance of HRR is underscored by the observation of genomic instability in HRR-deficient (HRD+) cells and, importantly, the association of cancer predisposition and developmental defects with mutations in HRR genes. PARP1 and PARP2 are required for SSB repair, while PARP1 is also involved in the repair of DNA double-strand breaks (DSBs) and replication fork damage. AZD9574 is a novel brain penetrant PARP1 inhibitor that acts by selectively inhibiting and trapping PARP1 at the sites of SSBs. While AZD9574 inhibited PARP1 enzymatic activity in all tested cell lines irrespective of the HRR status (IC50 range between 0.3 – 2 nM), colony formation assay in isogenic cell lines pairs confirmed higher potency and selectivity towards HRD+ models. In vivo, AZD9574 demonstrated dose-dependent efficacy in a BRCA1 mutant MDA-MB-436 subcutaneous xenograft model. Anti-tumour effects of AZD9574 were manifested by significant growth regressions that were durable after treatment withdrawal. An intracranial xenograft model of breast cancer brain metastases was developed to assess the efficacy of AZD9574 in the context of blood-brain barrier penetrance. Treatment of animals with established intracranial lesions showed sustained tumour growth suppression resulting in a significantly extended survival of tumour-bearing mice. Collectively, we believe that our data support the development of AZD9574 as a potential therapy for patients with HRD+ breast cancer whose disease has spread to the brain.This abstract was previously presented at AACR 2022 (Hamerlik et al, AACR 2022, Abs #3880)

Preclinical Characterization of AZD5305, A Next-Generation, Highly Selective PARP1 Inhibitor and Trapper

PURPOSE

We hypothesized that inhibition and trapping of PARP1 alone would be sufficient to achieve antitumor activity. In particular, we aimed to achieve selectivity over PARP2, which has been shown to play a role in the survival of hematopoietic/stem progenitor cells in animal models. We developed AZD5305 with the aim of achieving improved clinical efficacy and wider therapeutic window. This next-generation PARP inhibitor (PARPi) could provide a paradigm shift in clinical outcomes achieved by first-generation PARPi, particularly in combination.

EXPERIMENTAL DESIGN

AZD5305 was tested in vitro for PARylation inhibition, PARP-DNA trapping, and antiproliferative abilities. In vivo efficacy was determined in mouse xenograft and PDX models. The potential for hematologic toxicity was evaluated in rat models, as monotherapy and combination.

RESULTS

AZD5305 is a highly potent and selective inhibitor of PARP1 with 500-fold selectivity for PARP1 over PARP2. AZD5305 inhibits growth in cells with deficiencies in DNA repair, with minimal/no effects in other cells. Unlike first-generation PARPi, AZD5305 has minimal effects on hematologic parameters in a rat pre-clinical model at predicted clinically efficacious exposures. Animal models treated with AZD5305 at doses ≥0.1 mg/kg once daily achieved greater depth of tumor regression compared to olaparib 100 mg/kg once daily, and longer duration of response.

CONCLUSIONS

AZD5305 potently and selectively inhibits PARP1 resulting in excellent antiproliferative activity and unprecedented selectivity for DNA repair deficient versus proficient cells. These data confirm the hypothesis that targeting only PARP1 can retain the therapeutic benefit of nonselective PARPi, while reducing potential for hematotoxicity. AZD5305 is currently in phase I trials (NCT04644068).

Abstract 6302: Structure-based and property-based drug design of AZD9574, a CNS penetrant PARP1 selective inhibitor and trapper

PARP inhibitors exploit defects in DNA repair pathways to selectively target cancerous cells via PARP1 catalytic inhibition and PARP1 trapping onto the DNA. All known clinical PARP1 inhibitors bind at the same site at the catalytic center of the enzyme. However, despite this resemblance they show immensely different outcomes in terms of response rate in the clinic due to their varying degree of PARP trapping ability. Moreover, the first-generation PARP inhibitors were not optimized for selectivity across the PARP family potentially driving undesirable side effects, including intestinal toxicity from tankyrase inhibition or hematological toxicity from PARP2 inhibition. There has been strong rationale for the use of PARP inhibitors in neuro-oncology. However, the first-generation PARP inhibitors have limited CNS distribution as these drugs were not designed for brain penetration. Recently AstraZeneca has reported the discovery of AZD5305, a next generation PARP1 selective inhibitor and PARP1-DNA trapper which was not designed with a CNS penetrant profile. Given the unmet need of a brain penetrant PARP1 inhibitor, we set out to identify a highly potent and selective PARP1 inhibitor and trapper with CNS profile. In our next generation PARP1 inhibitor, we sought to retain the profile of AZD5305 and lower the efflux for CNS penetration. Despite the challenge of narrow SAR, we successfully used the structure- and property-based design approach to identify a brain penetrant PARP1 inhibitor and PARP1-DNA trapper. We used multiple medicinal chemistry maneuvers such as masking the hydrogen bond donors and core modifications to lower the efflux in order to achieve brain penetration. Further optimization of the nicotinamide mimetic core for potency and metabolic stability led us to the discovery of AZD9574.AZD9574 shows improved selectivity for PARP1 over PARP2 vs AZD5305 and retains its excellent selectivity over other PARP family members. It has low efflux in Caco2, MDCK-MDR1, and MDCK-MDR1-BCRP permeability assays and it also showed CNS penetration in rat and cynomolgus monkey. AZD9574 has excellent secondary pharmacology and acceptable physicochemical properties and good PK in preclinical species.In vitro, AZD9574 selectively inhibits the growth of BRCAm cell lines. Importantly, AZD9574 showed efficacy in an intracranial BRCA1m MDA-MB-436 xenograft model at doses of 3, 10 and 30 mg/kg QD, significantly extending the survival of tumor-bearing mice compared to vehicle control arm.In summary, AZD9574 is a next generation selective PARP1 inhibitor and trapper with CNS penetration. This profile makes it an ideal candidate for treating CNS malignancies or brain metastases that have a dependence on PARP inhibition either as single agent or in combination with other therapies.

Citation Format: Avipsa Ghosh, Sudhir M. Hande, Amber Balazs, Derek Barratt, Sabina Cosulich, Barry Davies, Sébastien Degorce, Kevin Embrey, Sonja Gill, Anders Gunnarsson, Giuditta Illuzzi, Peter Johnström, Jordan Lane, Carrie Larner, Rachel Lawrence, Elisabetta Leo, Andrew Madin, Elizabeth Martin, Lisa McWilliams, Lenka O’Connor, Mark O’Connor, Jonathan Orme, Fiona Pachl, Martin Packer, Andy Pike, Philip Rawlins, Marianne Schimpl, Magnus Schou, Anna Staniszewska, Wenzhan Yang, James Yates, Andrew Zhang, XiaoLa Zheng, Stephen Fawell, Petra Hamerlik, Jeffrey Johannes. Structure-based and property-based drug design of AZD9574, a CNS penetrant PARP1 selective inhibitor and trapper [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6302.

Exercise Interventions for Women with Ovarian Cancer: A Realist Review

Background: Despite evidence indicating the benefits of exercise interventions for women with ovarian cancer both during and following treatment, uptake is poor. There is limited research exploring the implementation of such interventions for this cohort of women. The purpose of this review was to identify implementation theories in relation to exercise interventions for women with stages I–IV ovarian cancer, both during and following treatment; to explain positive and negative contextual factors, which may help or hinder implementation; and to develop a theory on how exercise interventions for women with ovarian cancer may be implemented. Methods: This realist review sourced literature from five electronic databases: CINAHL plus, Medline, Embase, PsycINFO and Google Scholar. Methodological rigour was assessed using the relevant critical appraisal skills programme tools. Results: Nine papers were included. Two intervention stages were identified: first, optimising uptake by providing education to patients on the benefits of exercise, approaching patients when symptoms are adequately managed and offering a personalised exercise programme; second, adherence and retention are influenced by the provision of an “autoregulated” exercise programme with additional supportive infrastructure, individualised goal setting and symptom management support where required. Conclusion: Women with ovarian cancer are reluctant to engage in exercise interventions, despite the supporting evidence in terms of positive clinical outcomes. This realist review elucidates underlying mechanisms and important contextual factors that will support and guide the implementation of exercise interventions for this cohort of women.

Discovery of 5-{4-[(7-Ethyl-6-oxo-5,6-dihydro-1,5-naphthyridin-3-yl)methyl]piperazin-1-yl}-N-methylpyridine-2-carboxamide (AZD5305): A PARP1-DNA Trapper with High Selectivity for PARP1 over PARP2 and Other PARPs

Poly-ADP-ribose-polymerase (PARP) inhibitors have achieved regulatory approval in oncology for homologous recombination repair deficient tumors including BRCA mutation. However, some have failed in combination with first-line chemotherapies, usually due to overlapping hematological toxicities. Currently approved PARP inhibitors lack selectivity for PARP1 over PARP2 and some other 16 PARP family members, and we hypothesized that this could contribute to toxicity. Recent literature has demonstrated that PARP1 inhibition and PARP1-DNA trapping are key for driving efficacy in a BRCA mutant background. Herein, we describe the structure- and property-based design of 25 (AZD5305), a potent and selective PARP1 inhibitor and PARP1-DNA trapper with excellent in vivo efficacy in a BRCA mutant HBCx-17 PDX model. Compound 25 is highly selective for PARP1 over other PARP family members, with good secondary pharmacology and physicochemical properties and excellent pharmacokinetics in preclinical species, with reduced effects on human bone marrow progenitor cells in vitro.

Abstract 296: Structure-based and property-based drug design of AZD5305, a highly selective PARP1 inhibitor and trapper

Since the approval of olaparib in 2014 for BRCA mutated (BRCAm) ovarian cancer, many PARP inhibitors have been developed and have seen widespread success. However, as a class, these drugs are not without adverse events which have limited their ability to be combined with chemotherapy. Most first generation PARP inhibitors were developed and optimized before the concept of PARP1-DNA trapping was discovered as the mechanism by which PARP inhibitors exert their synthetic lethal effects on BRCAm cells. Moreover, the first generation PARP inhibitors were not optimized for selectivity across the PARP family potentially driving undesirable side effects, including intestinal toxicity from tankyrase inhibition or hematological toxicity from PARP2 inhibition. With this in mind, we set out to discover a best-in-class, second generation PARP inhibitor that was highly selective for PARP1 over the other 16 members of the PARP family, as well as a highly potent PARP1-DNA trapper.

PARP1 and PARP2 have a highly similar amino acid sequence, and most of the residues around the nicotinamide binding site are identical. However, there are some key residue differences in the helical domain which serves a regulator of the nicotinamide binding pocket. The publication of NMS-P118 in 2015 by Nerviano Medical Sciences showed that a highly selective PARP1 inhibitor could be found. This work inspired us to screen an extensive list of previously reported PARP inhibitors for selectivity against PARP2 and we found that FR257516 met the selectivity criteria as previously reported, but lacked the ability to trap PARP1 to DNA and hence lacked any activity in a cell colony formation assay in DLD-1 BRCA2-/- cells. Using parallel chemistry to generate diverse analogs, X-ray crystallography to enable structure-based design, and exploration of multiple nicotinamide mimetic cores, we were able to generate lead compound AZ4554, which was a PARP1 selective PARP1-DNA trapper with potent activity in BRCAm cells. Using concepts of property-based drug design, we were able to optimize lead compound AZ4554 into candidate drug AZD5305, making key improvements in secondary pharmacology, including reducing hERG activity, and intrinsic clearance in human microsomes through the introduction of polar atoms to lower logD without compromising permeability or oral bioavailability.

AZD5305 is a highly selective binder of PARP1 over PARP2 and other PARP enzymes by fluorescence polarization, surface plasmon resonance, and single molecule spectroscopy. It is highly potent against DLD-1 BRCA2-/- cells, while sparing isogenic BRCA WT cells. The secondary pharmacology of AZD5305 is remarkably clean, with hERG activity >40 µM. AZD5305 has a very favorable pre-clinical PK profile, low predicted human dose, and has shown efficacy in an MDA-MB-436 mouse xenograft model.

Citation Format: Sudhir Hande, Amber Balazs, Sébastien L. Degorce, Kevin Embrey, Avipsa Ghosh, Sonja J. Gill, Anders Gunnarsson, Giuditta Illuzzi, Jordan Lane, Carrie Larner, Elisabetta Leo, Andrew Madin, Lisa McWilliams, Mark J. O'Connor, Jonathan Orme, Fiona Pachl, Martin Packer, Andy Pike, Philip Rawlins, Marianne Schimpl, Anna D. Staniszewska, Andrew Zhang, Xiaolan Zheng, Jeffrey W. Johannes. Structure-based and property-based drug design of AZD5305, a highly selective PARP1 inhibitor and trapper [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 296.

Abstract 1272: In vitro cellular profiling of AZD5305, novel PARP1-selective inhibitor and trapper

PARP inhibitors (PARPi) have demonstrated clinical efficacy in cancers with defects in the homologous recombination repair (HRR) pathway. Recent advances in the understanding of the PARPi mechanism of action via stabilization of the PARP-DNA complex (trapping) and of the biological roles of the different PARP family members led to the development of AZD5305, a next generation, potent and selective PARP1 inhibitor and trapper. In this work, we disclose for the first time the profiling of AZD5305 in cellular models and how its activity differentiates from other PARPi. AZD5305 was able to potently inhibits overall PARylation in A549 cell line with IC50 of 3 nM, and to target PARP1 ~500 times more potently than PARP2 in A549 PARP1-KO, confirming its selectivity in cells. With our novel, sensitive and high-throughput immunofluorescence-based assay, we tested the ability of PARPi to trap PARP1 or PARP2 onto the chromatin of damaged or undamaged cells; olaparib, talazoparib and veliparib will be presented as comparative examples of non-selective PARPi. Unlike all the current clinical PARPi, AZD5305 was able to selectively induce PARP1 trapping upon treatments with concentrations as low as nanomolar (nM), whereas PARP2-trapping was not observed at any of the tested conditions. These optimal profiles of AZD5305 translated into greatly improved targeted anticancer effects in vitro compared to all other PARPi. In BRCA mutant (BRCAm) cells, treatments with AZD5305 led to antiproliferative IC50 in the single-digit nM, whilst there was no- or minimal effect in the isogenic paired BRCA wild type (BRCAwt) cells after treatments with double-digit µM concentrations. We further explored the effects of AZD5305 in genetic backgrounds “beyond BRCAm” and confirmed its superior antiproliferative and selective activity, particularly in cells isogenic for relevant genes in the HRR pathway, like PALB2 and RAD51. Screening of AZD5305 and other PARPi in larger cell lines panels revealed a differential clustering of AZD5305-treated cells between the sensitive versus the insensitive ones; this indicates that AZD5305 is also a unique instrumental tool to explore and refine selective PARP1-related activities in cancer cells, and the effects of targeting them, in different genetic backgrounds. With this goal, we are currently performing CRISPR/Cas9 screens to identify genes that, upon downregulation, cause sensitization to AZD5305. Preliminary results of these screens will be presented here. In summary, the optimal PARP1 inhibition and trapping profile of AZD5305 in cells demonstrated that AZD5305 is a next generation PARPi, with great potentials to become the best in class and deliver a markedly improved therapeutic index in the clinic.

Citation Format: Giuditta Illuzzi, Lisa McWilliams, Kunzah Jamal, Alessandro Galbiati, Sabrina Bentouati, Daniel Griffiths, Elisabetta Leo. In vitro cellular profiling of AZD5305, novel PARP1-selective inhibitor and trapper [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1272.

A Novel High-Throughput FLIPR Tetra-Based Method for Capturing Highly Confluent Kinetic Data for Structure-Kinetic Relationship Guided Early Drug Discovery

Target engagement by small molecules is necessary for producing a physiological outcome. In the past, a lot of emphasis was placed on understanding the thermodynamics of such interactions to guide structure-activity relationships. It is becoming clearer, however, that understanding the kinetics of the interaction between a small-molecule inhibitor and the biological target [structure-kinetic relationship (SKR)] is critical for selection of the optimum candidate drug molecule for clinical trial. However, the acquisition of kinetic data in a high-throughput manner using traditional methods can be labor intensive, limiting the number of molecules that can be tested. As a result, in-depth kinetic studies are often carried out on only a small number of compounds, and usually at a later stage in the drug discovery process. Fundamentally, kinetic data should be used to drive key decisions much earlier in the drug discovery process, but the throughput limitations of traditional methods preclude this. A major limitation that hampers acquisition of high-throughput kinetic data is the technical challenge in collecting substantially confluent data points for accurate parameter estimation from time course analysis. Here, we describe the use of the fluorescent imaging plate reader (FLIPR), a charge-coupled device (CCD) camera technology, as a potential high-throughput tool for generating biochemical kinetic data with smaller time intervals. Subsequent to the design and optimization of the assay, we demonstrate the collection of highly confluent time-course data for various kinase protein targets with reasonable throughput to enable SKR-guided medicinal chemistry. We select kinase target 1 as a special case study with covalent inhibition, and demonstrate methods for rapid and detailed analysis of the resultant kinetic data for parameter estimation. In conclusion, this approach has the potential to enable rapid kinetic studies to be carried out on hundreds of compounds per week and drive project decisions with kinetic data at an early stage in drug discovery.

An Overview of Treating People with Comorbid Dementia: Implications for Cancer Care

With increasing prevalence of both cancer and dementia in the UK, due to an ageing population, oncology healthcare professionals will experience higher numbers of people with both conditions. As dementia is highly heterogeneous and symptoms vary from individual to individual, it presents specific challenges for healthcare professionals, people with dementia and caregivers alike. This overview will describe current theories that explain the association between cancer and dementia, report prevalence rates and highlight the evidence on the impact of having a diagnosis of dementia on outcomes along the cancer pathway from cancer symptom detection to cancer treatment outcomes. It suggests that although prevalence rates of cancer and dementia are typically lower than other comorbidities, people with cancer and dementia have poorer cancer-related outcomes. This includes later stage cancer diagnoses, fewer cancer treatment options and an increased risk of death compared with people who have cancer alone or other comorbid conditions. Considerations for cancer treatment decision making and management are proposed to improve patient experience for this group.

A systematic review of the prevalence of comorbid cancer and dementia and its implications for cancer-related care

OBJECTIVES

A comorbid diagnosis of cancer and dementia (cancer-dementia) may have unique implications for patient cancer-related experience. The objectives were to estimate prevalence of cancer-dementia and related experiences of people with dementia, their carers and cancer clinicians including cancer screening, diagnosis, treatment and palliative care.

METHOD

Databases were searched (CINAHL, Psychinfo, Medline, Embase, BNI) using key terms such as dementia, cancer and experience. Inclusion criteria were as follows: (a) English language, (b) published any time until early 2016, (c) diagnosis of cancer-dementia and (d) original articles that assessed prevalence and/or cancer-related experiences including screening, cancer treatment and survival. Due to variations in study design and outcomes, study data were synthesised narratively.

RESULTS

Forty-seven studies were included in the review with a mix of quantitative (n = 44) and qualitative (n = 3) methodologies. Thirty-four studies reported varied cancer-dementia prevalence rates (range 0.2%-45.6%); the others reported reduced likelihood of receiving: cancer screening, cancer staging information, cancer treatment with curative intent and pain management, compared to those with cancer only. The findings indicate poorer cancer-related clinical outcomes including late diagnosis and higher mortality rates in those with cancer-dementia despite greater health service use.

CONCLUSIONS

There is a dearth of good-quality evidence investigating the cancer-dementia prevalence and its implications for successful cancer treatment. Findings suggest that dementia is associated with poorer cancer outcomes although the reasons for this are not yet clear. Further research is needed to better understand the impact of cancer-dementia and enable patients, carers and clinicians to make informed cancer-related decisions.

Abstract 548: Separation of Lipoprotein Particles Utilizing Asymmetric Flow Field-flow Fractionation and Quantitation of Apolipoprotein L1 in Human Plasma with IMER-UPLC-MS/MS

Apolipoprotein L1 (ApoL1) is an intriguing protein and was shown to be involved in numerous diseases states such as chronic kidney disease (CKD), cardiovascular diseases(CVD), Human Immunodeficiency Virus associated Nephropathy (HIVAN), systemic lupus erythematosus (SLE) (associated collapsing glomerulopathy), and type 2 diabetes(especially for people of African descent). People of African ancestry were shown to have either one or two alleles which contribute to their susceptibility of diseases related to CKD. ApoL1 is characterized as a HDL binding protein. In this work we studied ApoL1 binding to HDL by using a gentle size fractionation technique, asymmetric flow field-flow fractionation (AF4), and liquid chromatography (LC) with quantitative tandem mass spectrometry (MS/MS) detection. We injected 50 uL of whole plasma onto the AF4 system, where smaller HDL particles eluted first followed by the larger HDL, and then by LDL, IDL and VLDL particles. The lipoproteins were separated into 40 fractions and quantitatively analyzed using on-line trypsin digestion coupled with LC-MS/MS analysis. We analyzed plasma samples both with and without purification by UC. When HDL particles were separated by UC, apoL1 was found in the higher density HDL fractions, as was also found by previous studies. When HDL separated using AF4 with or without UC, apoL1 eluted in the larger HDL size region (12-13 nm). With UC vs. without UC, the apoL1 peptide signal intensities were reduced by more than 50%, indicating significant loss of apoL1 from the surface of HDL particles during UC. Our data on apoL1 provides further evidence for the fact that size and density are not directly interconvertible physical characteristics of lipoproteins. Furthermore, our data shows that apoL1 is also an example of exchangeable apolipoproteins whose binding can be significantly diminished due to the effect of intense shear forces during UC separation. This work also demonstrates the advantages of utilizing AF4-IMER-UPLC-MS/MS methodology to separate lipoprotein particles and study of their apolipoprotein composition.

Techniques to Enable 1536-Well Phenotypic Screening

Adaptation of phenotypic cell assays to 1536-well format brings major challenges in liquid handling for high-content assays requiring washing steps and coating of plates. In addition, problematic edge effects and reduced assay quality are frequently encountered. In this chapter, we describe the novel application of a centrifugal plate washer to facilitate miniaturization of 1536-well cell assays and a combination of techniques to reduce edge effects, all of which improved throughput and data quality. Cell assays currently limited in throughput because of cost and complex protocols may be enabled by the techniques presented in this chapter.

Abstract 192: Intra-Individual Temporal Variation of Lipid and Apolipoprotein Levels in Patients With Type II Diabetes Mellitus and Normolipidemic Individuals

Hypertriglyceridemia is frequently observed with diabetes mellitus (DM) and is associated with increased cardiovascular disease (CVD) risk. In conditions of insulin deficiency or resistance, increased levels of free fatty acids are seen by the liver, which trigger increased lipogenesis and secretion of triglyceride (TG) rich lipoprotein (TRL) particles. However, a high number of specific ApoC-III on TRL particles suppress their return to the liver leading to a continuous circulation of highly atherogenic TRL remnants. To better understand the effect of intra-individual temporal variations on the differentiation of lipid and apolipoprotein profiles in DM vs. normal individuals, a small time course study over a 4 week period was performed on 3 normolipidemic, and 3 type II DM patients. Our laboratory has developed a method to separate lipoproteins based on hydrodynamic size coupled with mass spectrometry based analysis. Whole serum and lipoprotein size fractions were analyzed for 8 apolipoproteins (ApoA-I, ApoA-II, ApoA-IV, B-100, ApoC-I, ApoC-II, ApoC-III and E) and non-polar lipids (FC, CE, TG) while monitoring other proteins (ApoD, ApoM, CETP, LCAT, PLTP, PON1 and SAA4). In whole serum over the course of 4 weeks, ApoA-IV levels of DM vs. normal subjects differed the most, 3.2 (0.7) vs. 1.8 (0.4) μM, respectively, more significantly than intra-group or intra-individual variations. On the contrary, significantly lower whole serum levels were found for FC, CE, ApoM and PON1 (Prob<0.01). HDL-ApoC-III/LDL-ApoC-III was also lower in DM vs. normal subjects, 3.0 (1.9) vs. 7.2 (4.1). By metrics of molar ratio measured in 20-35 nm LDL fractions, the most significant difference was found between DM vs. normal subjects in ApoC-III/ApoB-100 (1.8 (0.6) vs. 0.9 (0.3)), C-II/ApoB-100 (0.8 (0.4) vs. 0.4 (0.2)) and ApoE/ApoC-III (0.11 (0.09) vs. 0.24 (0.15)). These LDL composition differences indicate lower lipase activity and inhibition of LDL uptake. However, no significant differences were observed in these molar ratios as function of LDL particle size. In conclusion, due to less significant temporal deviations, apolipoprotein molar ratios are a more useful and informative measure of CVD risk in DM subjects than LDL size distribution characteristics.

Abstract 194: Lipid and Apolipoprotein Size Profile Differences Between Low and High Body Mass Index Individuals in Response to Fat Challenge

Clearance of elevated triglycerides (TG) level in response to fat challenge is a clinically significant indicator of CVD risk. HDL can play a key role in facilitating TG metabolism explaining the reverse correlation of HDL levels with CVD risk. In this study 6 individuals, low BMI (21-25) and 3 high BMI (30-49) were challenged with a meal containing ~90 g of total fat. Blood samples were drawn in fasting state before meal and 3 times after meal in 2, 4 and 6 hours. Serum was analyzed by a quantitative, multiplexed analytical workflow which included analysis of whole serum and the separation of lipoproteins by asymmetric flow field-flow fractionation where fractions were collected with 1 nm increments of 7-15 nm (HDL), 20-30 nm (LDL) and >30 nm lipoprotein classes. Dynamic light scattering was used to determine hydrodynamic size in each size fraction. Whole serum and individual fractions were analyzed to determine concentrations of apolipoproteins (apo A-I, A-II, A-IV, B, C-I, C-II, C-III and E), and non-polar lipids (FC, CE and TG), using two parallel liquid chromatography tandem mass spectrometry methods developed in our laboratory. In whole serum, the total TG levels for low and high BMI donors, relative to pre-meal levels (57-137 mg/dL and 111-183 md/dL), peaked at between the 2 and 4 hours post meal (103-214 mg/dL and 210-309 mg/dL). LCAT were lower (20%) and CETP levels were higher (30%), in low vs high BMI groups, but did not show change in repose to the fat challenge. In both low and high BMI groups, the most significant change between pre-meal and post-meal after 2 hours occurred in HDL-ApoC-I, HDL-ApoC-II, and HDL-ApoC-III levels mainly in the HDL size range of 9-12 nm (medium HDL) and at 13-16 nm (large HDL), with concurrent TG increase observed in LDL and remnant fractions (Prob-

Abstract 568: Lipidomic Comparison of Hyperglycemic and Normal Subjects Using Absolute Quantitation of >700 Lipid Species

The presence of diabetes mellitus in patients significantly increases the risk of cardiovascular disease, among many negative health outcomes. Several research groups have reported lipid species anomalies in subjects showing insulin resistance, including higher concentrations of sphingomyelin species relative to normal controls. Advances in lipidomic methodologies has allowed for the profiling of numerous lipid species in a single extraction and analytical run. We used the SCIEX Lipidyzer platform to determine the absolute concentration of 770 distinct lipid species from 52 subjects categorized into hyperglycemic (n=30) and normal subjects (n=22). Lipid species were determined from the following classes: cholesterol esters (CE), ceramides (CER), diacylglycerols (DAG), dihydroceramide (DCER), free fatty acids (FFA), hexosylceramides (HCER), lactosylceramides (LCER), lysophosphatidylcholines (LPC), lysophosphatidylethanolamines (LPE), phosphatidylcholines (PC), phosphatidylethanolamines (LPE), sphingomyelins (SM), and triacylglycerols (TAG).

After normalizing by the sum of total apolipoprotein A and apolipoprotein B (to account for the possibility of reduced particle number due to medicinal intervention), lipids both by class and species were compared using one way analysis of variance. On a class level, relative to normal subjects, hyperglycemic patients showed increased levels of CER and FFA. Individual lipid species of these classes that were higher in hyperglycemic patients include CER(18:0), CER(20:0), CER(24:1), FFA(16:0), FFA(16:1), FFA(18:0), FFA(18:1), FFA(18:2), FFA(18:3), and FFA(20:3) Differences were also found in SM concentrations between hyperglycemic and normal patients resulting in a higher the SM/PC ratio, indicating changes in the lipid fluidity of the shell in lipoprotein particles of hyperglycemic patients. On a species level, SM(16:0), SM(18:1), and SM(24.1), were elevated in hyperglycemic subjects relative to normal subjects. This finding of elevated unsaturated SM species in hyperglycemic patients is at odds with other studies where it was found that the saturated SM moieties were elevated in insulin resistant subjects.

Enabling 1536-Well High-Throughput Cell-Based Screening through the Application of Novel Centrifugal Plate Washing

Cell-based assays have long been important within hit discovery paradigms; however, improving the disease relevance of the assay system can positively affect the translation of small-molecule drug discovery, especially if adopted in the initial hit identification assay. Consequently, there is an increasing need for disease-relevant assay systems capable of running at large scale, including the use of induced pluripotent stem cells and donor-derived primary cells. Major hurdles to adopting these assays for high-throughput screening are the cost, availability of cells, and complex protocols. Miniaturization of such assays to 1536-well format is an approach that can reduce costs and increase throughput. Adaptation of these complex cell assays to 1536-well format brings major challenges in liquid handling for high-content assays requiring washing steps and coating of plates. In addition, problematic edge effects and reduced assay quality are frequently encountered. In this study, we describe the novel application of a centrifugal plate washer to facilitate miniaturization of a range of 1536-well cell assays and techniques to reduce edge effects, all of which improved throughput and data quality. Cell assays currently limited in throughput because of cost and complex protocols may be enabled by the techniques presented in this study.

Understanding Cytotoxicity and Cytostaticity in a High-Throughput Screening Collection

While mechanisms of cytotoxicity and cytostaticity have been studied extensively from the biological side, relatively little is currently understood regarding areas of chemical space leading to cytotoxicity and cytostasis in large compound collections. Predicting and rationalizing potential adverse mechanism-of-actions (MoAs) of small molecules is however crucial for screening library design, given the link of even low level cytotoxicity and adverse events observed in man. In this study, we analyzed results from a cell-based cytotoxicity screening cascade, comprising 296 970 nontoxic, 5784 cytotoxic and cytostatic, and 2327 cytostatic-only compounds evaluated on the THP-1 cell-line. We employed an in silico MoA analysis protocol, utilizing 9.5 million active and 602 million inactive bioactivity points to generate target predictions, annotate predicted targets with pathways, and calculate enrichment metrics to highlight targets and pathways. Predictions identify known mechanisms for the top ranking targets and pathways for both phenotypes after review and indicate that while processes involved in cytotoxicity versus cytostaticity seem to overlap, differences between both phenotypes seem to exist to some extent. Cytotoxic predictions highlight many kinases, including the potentially novel cytotoxicity-related target STK32C, while cytostatic predictions outline targets linked with response to DNA damage, metabolism, and cytoskeletal machinery. Fragment analysis was also employed to generate a library of toxicophores to improve general understanding of the chemical features driving toxicity. We highlight substructures with potential kinase-dependent and kinase-independent mechanisms of toxicity. We also trained a cytotoxic classification model on proprietary and public compound readouts, and prospectively validated these on 988 novel compounds comprising difficult and trivial testing instances, to establish the applicability domain of models. The proprietary model performed with precision and recall scores of 77.9% and 83.8%, respectively. The MoA results and top ranking substructures with accompanying MoA predictions are available as a platform to assess screening collections.

Drug-induced toxicity and patient reported outcomes in rheumatoid arthritis patients following intensive treated-to-target strategy: does ceasing therapy due to toxicity worsen outcomes in long term?

AIM

While the introduction of the treat-to-target (T2T) strategy has been an important advance in the management of rheumatoid arthritis (RA), the potential for increased toxicity due to use of concurrent drugs could adversely affect patient reported outcomes (PROs). The objective was to determine whether the cessation of therapy due to toxicity affects long-term improvement in PROs in patients treated according to T2T strategy.

METHODS

A total of 149 patients from an inception cohort of early RA were included. The occurrence and severity of toxicity were monitored at each visit over 3 years. PROs studied were function (measured using health assessment questionnaire); pain, fatigue and patient global assessment (PtGA) all assessed using a 100 mm visual analogue scale; helplessness and health-related quality of life (HRQoL). For each PRO, effect of drug withdrawal was measured by comparing mean change in PROs among patients with no/temporary vs. permanent withdrawal. In addition, effects of frequency of drug withdrawals, weeks to withdrawal and number of drugs withdrawn were analysed using linear regression.

RESULT

After 3 years, 56 (37.4%) patients ceased at least one drug permanently due to toxicity. Patients with no/temporary withdrawal (n = 93) achieved significantly greater improvement in function (mean change = -0.54 vs. -0.31, p = 0.033), pain (mean change = -39.82 vs. -5.02, p = 0.018), fatigue (mean change = -29.14 vs. -14.76, p = 0.015) and PtGA (mean change = -29.64 vs. -17.00, p = 0.018) compared with their counterparts. Higher frequency of withdrawals was associated with lesser improvements in function, pain, fatigue and PtGA, while the number of drugs withdrawn and the weeks to withdrawal had lesser effects. However, the cessation of the drugs due to their toxicity did not have a significant association with HRQoL and helplessness.

CONCLUSION

Improvements in function, pain, fatigue and PtGA at 3 years were diminished for patients who ceased drugs due to toxicity while broader measures of HRQoL were not affected.

High-Throughput Cell Toxicity Assays

Understanding compound-driven cell toxicity is vitally important for all drug discovery approaches. With high-throughput screening (HTS) being the key strategy to find hit and lead compounds for drug discovery projects in the pharmaceutical industry [1], an understanding of the cell toxicity profile of hit molecules from HTS activities is fundamentally important. Recently, there has been a resurgence of interest in phenotypic drug discovery and these cell-based assays are now being run in HTS labs on ever increasing numbers of compounds. As the use of cell assays increases the ability to measure toxicity of compounds on a large scale becomes increasingly important to ensure that false hits are not progressed and that compounds do not carry forward a toxic liability that may cause them to fail at later stages of a project. Here we describe methods employed in the AstraZeneca HTS laboratory to carry out very large scale cell toxicity screening.

Treatment-induced stable, moderate reduction in blood cell counts correlate to disease control in early rheumatoid arthritis

BACKGROUND

Treatment of rheumatoid arthritis (RA) has become more intensive, thereby raising concerns regarding toxicities, including leucopenia. The objective was to analyse cell counts obtained as routine surveillance for adverse effects to assess the effect of intensive treatment and treatment dosage and to examine correlations to disease activity scores.

METHODS

Patients with early RA were treated with combinations of disease-modifying anti-inflammatory drugs according to pre-defined rules, with dose adjustments contingent on residual disease activity and tolerance.

RESULTS

Mean leucocyte, neutrophil and platelet counts fell with levels that correlated to disease activity scores. The strongest correlation was between platelets and disease activity scores. There was a modest, inverse correlation between methotrexate dose and monocyte and lymphocyte counts. No serious toxicity associated with the therapy was seen.

CONCLUSION

Moderate reductions in cell counts are well tolerated in RA and appear to contribute to disease control.

Influence of ionic strength, electrolyte type, and NOM on As(V) adsorption onto TiO2

As(V) adsorption onto a commercially available TiO2 (Degussa P25) in NaCl or NaClO4 at various concentrations (0.001-0.1 M) was investigated. The effect of natural organic matter (NOM) on As(V) removal through the adsorption by TiO2 was also examined. In either electrolyte, As(V) adsorption onto TiO2 increased with the increase of ionic strength under alkaline conditions (pH 7.0-11.0). Under acidic conditions (pH 4.0-6.0), the adsorption of As(V) onto TiO2 was insensitive to ionic strength in NaClO4 electrolyte but decreased with increasing ionic strength in NaCl electrolyte. The presence of 2-15 mg/L NOM as C significantly decreased the fraction of As(V) adsorbed onto TiO2 at pH 6.0 regardless of the initial As(V) concentration (1-15 microM). The measurement of zeta potential of TiO2 with and without As(V) suggests that the presence of As(V) can shift the point of zero charge (pH(pzc)) of TiO2 to a lower pH value. The overall data presented in this study suggest that As(V) can form both inner-sphere and outer-sphere complexes on TiO2 surface, and NOM is an important factor controlling As(V) adsorption onto TiO2.

Relationship between elemental carbon, total carbon, and diesel particulate matter in several underground metal/non-metal mines

Elemental carbon (EC) is currently used as a surrogate for diesel particulate matter (DPM) in underground mines since it can be accurately measured at low concentrations and diesels are the only source of submicrometer EC in underground mines. A disadvantage of using EC as a surrogate for DPM is that the fraction of EC in DPM is a function of various engine parameters and fuel formulations, etc. In order to evaluate how EC predicts DPM in the underground mining atmosphere, measurements of total carbon (TC; representing over 80% of the DPM) and EC were taken away from potential interferences in four underground metal/non-metal mines during actual production. In a controlled atmosphere, DPM mass, TC, and EC measurements were also collected while several different types of vehicles simulated production with and without different types of control technologies. When diesel particulate filters (DPFs) were not used, both studies showed that EC could be used to predict DPM mass or TC. The variability of the data started to increase at TC concentrations below 230 microg/m3 and was high (> +/- 20%) at TC concentrations below 160 microg/m3, probably due to the problem with sampling organic carbon (OC) at these concentrations. It was also discovered that when certain DPFs were used, the relationship between DPM and EC changed at lower DPM concentrations.

Adaptation of the RAQoL for use in Australia

Quality of life is an important patient-reported outcome of rheumatoid arthritis (RA) in addition to structural and functional outcomes. The RAQoL (Rheumatoid Arthritis Quality of Life questionnaire) was developed in the UK and the Netherlands as a disease-specific tool. It was adapted for use in the Australian social context and the reliability and validity was tested. A lay panel assessed the UK version and adapted the wording for use within Australia. Reliability and validity were assessed by a postal survey of the RAQoL and comparator questionnaires to 100 patients with RA. The RAQoL was easily adapted into Australian-English. Test-retest reliability was high with a Spearman rank correlation coefficient of 0.93. RAQoL scores correlated well with patient-perceived disease activity and severity--indicating good validity. The Australian version of the RAQoL is a valid and reliable tool for the assessment of quality of life. It is practical, easy to administer and has good potential for use in clinical settings and trials in Australia.

Teacher discipline and child misbehavior in day care: untangling causality with correlational data

Day-care centers provide an ideal, underused setting for studying the developmental processes of child psychopathology. The influence of day-care teachers' lax and overreactive discipline on children's behavior problems was examined, as was the influence of children's behavior problems on teachers' discipline. Participants were 145 children and 16 day-care teachers from 8 classrooms in a day-care center for children from low-income families. Two techniques are presented for estimating causal relations based on correlational data gathered from day-care centers: 2-stage least squares and simultaneous structural equation modeling. Across techniques, teachers' laxness strongly influenced child misbehavior, and child misbehavior influenced both teachers' overreactivity and laxness. Teachers' overreactivity did not influence child misbehavior

Teacher discipline and child misbehavior in day care: untangling causality with correlational data

Day-care centers provide an ideal, underused setting for studying the developmental processes of child psychopathology. The influence of day-care teachers' lax and overreactive discipline on children's behavior problems was examined, as was the influence of children's behavior problems on teachers' discipline. Participants were 145 children and 16 day-care teachers from 8 classrooms in a day-care center for children from low-income families. Two techniques are presented for estimating causal relations based on correlational data gathered from day-care centers: 2-stage least squares and simultaneous structural equation modeling. Across techniques, teachers' laxness strongly influenced child misbehavior, and child misbehavior influenced both teachers' overreactivity and laxness. Teachers' overreactivity did not influence child misbehavior

Serotonergic agents that activate 5HT2A receptors prevent NMDA antagonist neurotoxicity

Phencyclidine, ketamine, and other agents that block NMDA glutamate receptors trigger a schizophrenia-like psychosis in humans and induce pathomorphological changes in cerebrocortical neurons in rat brain. Accumulating evidence suggests that a complex network disturbance involving multiple transmitter receptor systems is responsible for the neuronal injury, and it is proposed that a similar network disturbance is responsible for the psychotomimetic effects of NMDA antagonists, and might also be involved in the pathophysiology of schizophrenia. In the present study we present evidence that serotonergic agents possessing 5HT2A agonist activity prevent NMDA antagonist neurotoxicity in rat brain. It is proposed that 5HT2A agonists may also prevent the psychotomimetic effects of NMDA antagonists. Among the 5HT2A agonists examined and found to be neuroprotective are LSD and related hallucinogens. The apparent contradiction in proposing that these agents might have antipsychotic properties is resolved by evidence linking their hallucinogenic activity to agonist action at 5HT2C receptors, whereas antipsychotic activity would be attributable to agonist action at 5HT2A receptors.