Structure-Based Design and Evaluation of Reversible KRAS G13D Inhibitors

Oncogenic KRAS mutations were identified decades ago, yet the selective inhibition of specific KRAS mutant proteins represents an ongoing challenge. Recent progress has been made in targeting certain P-loop mutant proteins, in particular KRAS G12C, for which the covalent inhibition of the GDP state via the Switch II pocket is now a clinically validated strategy. Inhibition of other KRAS mutant proteins such as KRAS G13D, on the other hand, still requires clinical validation. The remoteness of the D13 residue relative to the Switch II pocket in combination with the solvent exposure and conformational flexibility of the D13 side chain, as well as the difficulties of targeting carboxylate residues covalently, renders this specific protein particularly challenging to target selectively. In this report, we describe the design and evaluation of potent and KRAS G13D-selective reversible inhibitors. Subnanomolar binding to the GDP state Switch II pocket and biochemical selectivity over WT KRAS are achieved by leveraging a salt bridge with D13.

POS1063 RHEUMATOLOGIST AND PATIENT PERSPECTIVES ON IMPLEMENTING CARDIOVASCULAR RISK PREVENTION IN THE MANAGEMENT OF PSORIASIS: A QUALITATIVE STUDY

Background:

Psoriatic arthritis (PsA) is an immune-mediated musculoskeletal disease associated with excess risk for cardiovascular disease (CVD). New US-based guidelines recognize psoriasis as a CVD risk enhancer; however, patients with PsA often do not have CVD risk factors identified nor managed.

Objectives:

This study examines strategies to improve CVD prevention care from the perspective of rheumatologists and patients with PsA.

Methods:

Semi-structured qualitative interviews were conducted using an interview guide based on the Consolidated Framework for Implementation Research to examine the perspectives of rheumatologists (N = 8) and patients with psoriatic arthritis managed by rheumatologists (N = 8) on barriers/facilitators to CVD prevention. Interviews were transcribed and coded using an integrated approach designed to enhance reliability and validity facilitated by NVivo software.

Results:

Most rheumatologists confirmed that they were not regularly engaging in CVD prevention care with psoriatic arthritis patients. Providers reported sometimes counseling and screening for CVD risk, but they were not regularly prescribing statins and not as willing to do so. Reasons included a lack of familiarity or comfort with guidelines, concern about working outside of their scope of practice, confusing boundaries between other clinicians, and time constraints. Most patients confirmed that it was uncommon for their rheumatologists to engage them in CVD prevention care but expressed desire for their rheumatologists inform them of the risk, and were open to CVD prevention care from them.

Conclusion:

We identified several potentially modifiable barriers to CVD screening and management. These findings will inform the design of a clinical trial comparing the effectiveness of rheumatologist implementation of CVD guideline-based counseling, screening and prescribing statins when appropriate in patients with PsA.

Figure 1.

Barriers to CVD screening and management among patients with PsA in a rheumatology practice setting and potential strategies to address those barriers. Abbreviations: CV = cardiovascular; SOC = standard of care.

Disclosure of Interests:

Alexis Ogdie Consultant of: Abbvie, Amgen, BMS, Celgene, Corrona, Gilead, Janssen, Lilly, Novartis, Pfizer, UCB, Grant/research support from: Pfizer to Penn, Novartis to Penn, Amgen to Forward/NDB, Alix Gustafson: None declared, Adina Lieberman: None declared, Jennifer Mason: None declared, April Armstrong: None declared, Nehal Mehta Consultant of: Amgen, Eli Lilly, and Leo Pharma receiving grants/other payments, Grant/research support from: AbbVie, Celgene, Janssen Pharmaceuticals, Inc, and Novartis receiving grants and/or research funding and as a principal investigator for the National Institute of Health receiving grants and/or research funding., Employee of: NNM is a full-time US government employee, Rinad Beidas Consultant of: Camden Coalition of Healthcare Providers in the past 3 years. She currently is a consultant for United Behavioral Health. She serves on the Optum Behavioral Health Clinical and Scientific Advisory Council. Dr. Beidas receives royalties from Oxford University Press., Joel Gelfand Shareholder of: Dr Gelfand is a co-patent holder of resiquimod for treatment of cutaneous T-cell lymphoma, and he is a deputy editor for the Journal of Investigative Dermatology, receiving honoraria from the Society for Investigative Dermatology., Paid instructor for: CME work related to psoriasis that was supported indirectly by Eli Lilly and Company and Ortho Dermatologics, Consultant of: Bristol-Myers Squibb, Boehringer Ingelheim, GlaxoSmithKline, Janssen Biologics, Novartis Corp, UCB (Data Safety and Monitoring Board), Sanofi, and Pfizer Inc, Grant/research support from: research grants (to the Trustees of the University of Pennsylvania) from AbbVie, Janssen, Novartis Corp, Celgene, OrthoDermatologics, and Pfizer Inc.

Evaluation of an Outpatient Pharmacist Consult Service at a Large Academic Medical Center

Objective:

To evaluate a novel outpatient pharmacist consult service in a large academic medical center.

Setting:

Four outpatient pharmacies that are part of a large academic medical center

Methods:

An outpatient pharmacist consult order was created and embedded in the electronic medical record (EMR). Medical center providers utilized this consult order when identifying patients in need of specific services provided by outpatient pharmacists. Descriptive data about each individual consult was collected including number completed, type of service, and duration. Rate of accepted pharmacy recommendations and patient cost savings were also evaluated. A survey was administered at the completion of the study period to assess provider and pharmacist satisfaction with the service. Patient demographic information was collected for those who had a documented completed consult.

Results:

A total of 193 consults were completed: 137 immunizations, 37 care affordability, 15 education, 3 polypharmacy and 1 OTC recommendation. 89% of completed consults took pharmacists 20 minutes or less to complete. Of completed care affordability consults (n=31), 55% of patients saved between $100 - $500 per medication fill. Of providers who completed a survey and utilized the service (n=12), 83.3% were extremely satisfied and 16.7% were satisfied with it. The provider acceptance rate of pharmacist’s recommendations was 74%.

Conclusion:

Implementation of an outpatient pharmacist consult service provided an alternative method for the utilization of pharmacist provided MTM services in outpatient pharmacies at a large academic medical center. The service was well received by both providers and pharmacists.

Implementation of the CYP Index for the Design of Selective Tryptophan-2,3-dioxygenase Inhibitors

A class of imidazoisoindole (III) heme-binding indoleamine-2,3-dioxygenase (IDO1) inhibitors were optimized via structure-based drug design into a series of tryptophan-2,3-dioxygenase (TDO)-selective inhibitors. Kynurenine pathway modulation was demonstrated in vivo, which enabled evaluation of TDO as a potential cancer immunotherapy target. As means of mitigating the risk of drug-drug interactions arising from cytochrome P450 inhibition, a novel property-based drug design parameter, herein referred to as the CYP Index, was implemented for the design of inhibitors with appreciable selectivity for TDO over CYP3A4. We anticipate the CYP Index will be a valuable design parameter for optimizing CYP inhibition of any small molecule inhibitor containing a Lewis basic motif capable of binding heme.

Pharmacological Induction of RAS-GTP Confers RAF Inhibitor Sensitivity in KRAS Mutant Tumors

Targeting KRAS mutant tumors through inhibition of individual downstream pathways has had limited clinical success. Here we report that RAF inhibitors exhibit little efficacy in KRAS mutant tumors. In combination drug screens, MEK and PI3K inhibitors synergized with pan-RAF inhibitors through an RAS-GTP-dependent mechanism. Broad cell line profiling with RAF/MEK inhibitor combinations revealed synergistic efficacy in KRAS mutant and wild-type tumors, with KRAS^G13D mutants exhibiting greater synergy versus KRAS^G12 mutant tumors. Mechanistic studies demonstrate that MEK inhibition induced RAS-GTP levels, RAF dimerization and RAF kinase activity resulting in MEK phosphorylation in synergistic tumor lines regardless of KRAS status. Taken together, our studies uncover a strategy to rewire KRAS mutant tumors to confer sensitivity to RAF kinase inhibition.

Abstract 874: Pharmacologically induced RAS-GTP levels and CRAF-BRAF hetero-dimerization drive sensitization to Type II pan-RAF inhibitors in KRAS mutant cancer

Although effective in BRAF V600 mutant melanoma, Type 1.5 RAF inhibitors such as vemurafinib and dabrafenib have not proven to be successful in KRAS mutant cancers, neither as single agent nor in combination with MEK inhibitors. Through large-scale cellular compound combination screening we found that Type II RAF inhibitors such as AZ-628 do show synergistic activity with MEK inhibitors in multiple KRAS mutant indications, including NSCLC, colorectal cancer and ovarian cancer. The combination of Type II RAF inhibitors and MEK inhibitors demonstrates robust and durable abrogation of MAPK signaling both on canonical markers of MAPK activity such as pERK and pRSC as well as transcriptional output. We also observe synergistic in vivo tumor growth inhibition in two independent models of KRAS mutant cancer by this combination treatment. We found that treatment with MEK inhibitors alone drives the increase of active RAS-GTP levels and induces CRAF:BRAF hetero-dimerization. These induced dimers are active and able to phosphorylate MEK in vitro. This increased dimerization renders cells sensitive to Type 2 RAF inhibitors. We find that this effect is not limited to KRAS mutant cells, as a subset of KRAS wild-type cells show increased RAS-GTP levels upon MEK inhibitor treatment. These cells also show synergistic sensitivity to Type 2 RAF inhibition. Additionally, we observed significantly higher synergy and higher RAS-GTP levels in KRAS G13D mutant cells, which have intrinsically high GDP exchange and low intrinsic GTP hydrolysis. Finally, we show that GDC-0941 and GDC-0032, two broad PI3K inhibitors, also induce RAS-GTP levels in cells independent of PIK3CA or KRAS mutation status. We subsequently observed a synergistic sensitivity to Type 2 RAF inhibitors in these PI3K inhibitor-treated cells. Overall, we demonstrate that pharmacologic inhibition of MEK or PI3K increases RAS-GTP levels and drives increased CRAF:BRAF hetero-dimerization. This in turn sensitizes cells to Type 2 RAF inhibition, leading to a synergistic drug effect. Combination of these inhibitors may be a viable therapeutic approach in KRAS mutant cancer, and may be especially effective in KRAS G13D-carrying tumors.

Citation Format: Christiaan N. Klijn, Ivana Yen, Frances Shanahan, Mark Merchant, Christine Orr, Thomas Hunsaker, Matthew Durk, Hank La, Xiaoling Zhang, Scott Martin, Eva Lin, John Chan, Yihong Yu, Dhara Amin, Amy Gustafson, Scott Foster, Joachim Rudolph, Shiva Malek. Pharmacologically induced RAS-GTP levels and CRAF-BRAF hetero-dimerization drive sensitization to Type II pan-RAF inhibitors in KRAS mutant cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 874.

Development of a mass spectrometry-based tryptophan 2, 3-dioxygenase assay using liver cytosol from multiple species

A novel and rapid method to determine the potency of inhibitors for tryptophan 2, 3-dioxygenase (TDO2) activities in human and preclinical species was successfully developed and validated utilizing LC-MS/MS. Previously reported TDO2 activity assays are resource intensive, requiring cloning and overexpression of TDO2. Here, we demonstrated that liver cytosol contained sufficient active TDO2 for evaluating the potency of TDO2 inhibitors across multiple species. TDO2 expression in human cytosol was estimated by LC-MS/MS to be 41 pmoL/mg cytosolic protein, with similar levels in dogs and monkeys, whereas mice and rats had 9.6 and 5.0-fold greater expression, respectively. Reaction conditions for TDO2-mediated conversion of l-tryptophan to kynurenine were optimized. Marked differences in kinetic parameters and inhibition potency were observed in TDO2 across species, with different Km values in dog (0.055 mM), monkey (0.070 mM), human (0.19 mM), mouse (0.32 mM) and rat (0.36 mM). Subsequently, IC50 values were determined for a series of TDO2 inhibitors in liver cytosol of five species, and good agreement with the literature values was observed for human enzyme. Taken together, these data indicate that TDO2 inhibition can be rapidly determined in readily available hepatic cytosol to assess potential species differences in potency.

Aminoisoxazoles as Potent Inhibitors of Tryptophan 2,3-Dioxygenase 2 (TDO2)

Tryptophan 2,3-dioxygenase 2 (TDO2) catalyzes the conversion of tryptophan to the immunosuppressive metabolite kynurenine. TDO2 overexpression has been observed in a number of cancers; therefore, TDO inhibition may be a useful therapeutic intervention for cancers. We identified an aminoisoxazole series as potent TDO2 inhibitors from a high-throughput screen (HTS). An extensive medicinal chemistry effort revealed that both the amino group and the isoxazole moiety are important for TDO2 inhibitory activity. Computational modeling yielded a binding hypothesis and provided insight into the observed structure-activity relationships. The optimized compound 21 is a potent TDO2 inhibitor with modest selectivity over indolamine 2,3-dioxygenase 1 (IDO1) and with improved human whole blood stability.

Loss of dual leucine zipper kinase signaling is protective in animal models of neurodegenerative disease

Hallmarks of chronic neurodegenerative disease include progressive synaptic loss and neuronal cell death, yet the cellular pathways that underlie these processes remain largely undefined. We provide evidence that dual leucine zipper kinase (DLK) is an essential regulator of the progressive neurodegeneration that occurs in amyotrophic lateral sclerosis and Alzheimer's disease. We demonstrate that DLK/c-Jun N-terminal kinase signaling was increased in mouse models and human patients with these disorders and that genetic deletion of DLK protected against axon degeneration, neuronal loss, and functional decline in vivo. Furthermore, pharmacological inhibition of DLK activity was sufficient to attenuate the neuronal stress response and to provide functional benefit even in the presence of ongoing disease. These findings demonstrate that pathological activation of DLK is a conserved mechanism that regulates neurodegeneration and suggest that DLK inhibition may be a potential approach to treat multiple neurodegenerative diseases.

Selective Inhibitors of Dual Leucine Zipper Kinase (DLK, MAP3K12) with Activity in a Model of Alzheimer's Disease

Significant data exists to suggest that dual leucine zipper kinase (DLK, MAP3K12) is a conserved regulator of neuronal degeneration following neuronal injury and in chronic neurodegenerative disease. Consequently, there is considerable interest in the identification of DLK inhibitors with a profile compatible with development for these indications. Herein, we use structure-based drug design combined with a focus on CNS drug-like properties to generate compounds with superior kinase selectivity and metabolic stability as compared to previously disclosed DLK inhibitors. These compounds, exemplified by inhibitor 14, retain excellent CNS penetration and are well tolerated following multiple days of dosing at concentrations that exceed those required for DLK inhibition in the brain.

Abstract 4967: RAF kinase inhibition synergizes with MEK inhibitors in KRAS mutant tumors

While activating mutations in the KRAS oncogene frequently drive tumorigenesis in human cancers (40% CRC, 20% NSCLC) through constitutive activation of the MAPK pathway, there are currently no targeted treatments available for KRAS mutant cancers. Inhibitors of the individual nodes of the MAPK pathway have been developed, but these molecules have been largely ineffective against KRAS mutant tumors in the clinic. Multiple studies have shown rational combinations of MAPK inhibitors may have anti-tumor activity in KRAS mutant models. In order to understand the versatility of combining RAF inhibitors in this context, we conducted a library screen consisting of 430 small molecule tool compounds in combination with RAF inhibitor AZ-628. Here we show: RAF inhibitors combine especially well with other MAPK pathway inhibitors in KRAS mutant tumor cells. In particular, Type II RAF inhibitors are synergistic with the MEK inhibitor Cobimetinib in vitro and exhibit tumor regressing efficacy in xenograft mouse model studies in vivo. Mechanistically, we have found the MEK inhibitor disables ERK induced negative feedback on the MAPK pathway resulting in activation of CRAF in a KRAS dependent manner. The combination of RAF with MEK inhibition blunts KRAS-dependent activation of CRAF kinase activity and robustly inhibits MAPK signaling, thereby driving efficacy in KRAS mutant tumors. Broad cell line profiling with the combination of RAF and MEK inhibitors demonstrates that a majority of KRAS mutant lung and colorectal tumor lines exhibit synergy with the combination. Therefore, combining a Type II pan-RAF inhibitor with a MEK inhibitor has the potential to improve the therapeutic outcome in KRAS mutant cancers.

Citation Format: Ivana Yen, Christiaan Klijn, Frances Shanahan, Mark Merchant, Christine Orr, Thomas Hunsaker, Matthew Durk, Hank La, Xiaolin Zhang, Scott Martin, Eva Lin, John Chan, Yihong Yu, Amy Gustafson, Joachim Rudolph, Shiva Malek. RAF kinase inhibition synergizes with MEK inhibitors in KRAS mutant tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4967. doi:10.1158/1538-7445.AM2017-4967

From a novel HTS hit to potent, selective, and orally bioavailable KDM5 inhibitors

A high-throughput screening (HTS) of the Genentech/Roche library identified a novel, uncharged scaffold as a KDM5A inhibitor. Lacking insight into the binding mode, initial attempts to improve inhibitor potency failed to improve potency, and synthesis of analogs was further hampered by the presence of a C-C bond between the pyrrolidine and pyridine. Replacing this with a C-N bond significantly simplified synthesis, yielding pyrazole analog 35, of which we obtained a co-crystal structure with KDM5A. Using structure-based design approach, we identified 50 with improved biochemical, cell potency and reduced MW and lower lipophilicity (LogD) compared with the original hit. Furthermore, 50 showed lower clearance than 9 in mice. In combination with its remarkably low plasma protein binding (PPB) in mice (40%), oral dosing of 50 at 5mg/kg resulted in unbound C_max ∼2-fold of its cell potency (PC9 H3K4Me3 0.96μM), meeting our criteria for an in vivo tool compound from a new scaffold.

Design and evaluation of 1,7-naphthyridones as novel KDM5 inhibitors

Features from a high throughput screening (HTS) hit and a previously reported scaffold were combined to generate 1,7-naphthyridones as novel KDM5 enzyme inhibitors with nanomolar potencies. These molecules exhibited high selectivity over the related KDM4C and KDM2B isoforms. An X-ray co-crystal structure of a representative molecule bound to KDM5A showed that these inhibitors are competitive with the co-substrate (2-oxoglutarate or 2-OG).

Discovery of GluN2A-Selective NMDA Receptor Positive Allosteric Modulators (PAMs): Tuning Deactivation Kinetics via Structure-Based Design

The N-methyl-D-aspartate receptor (NMDAR) is a Na(+) and Ca(2+) permeable ionotropic glutamate receptor that is activated by the coagonists glycine and glutamate. NMDARs are critical to synaptic signaling and plasticity, and their dysfunction has been implicated in a number of neurological disorders, including schizophrenia, depression, and Alzheimer's disease. Herein we describe the discovery of potent GluN2A-selective NMDAR positive allosteric modulators (PAMs) starting from a high-throughput screening hit. Using structure-based design, we sought to increase potency at the GluN2A subtype, while improving selectivity against related α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). The structure-activity relationship of channel deactivation kinetics was studied using a combination of electrophysiology and protein crystallography. Effective incorporation of these strategies resulted in the discovery of GNE-0723 (46), a highly potent and brain penetrant GluN2A-selective NMDAR PAM suitable for in vivo characterization.

Scaffold-Hopping and Structure-Based Discovery of Potent, Selective, And Brain Penetrant N-(1H-Pyrazol-3-yl)pyridin-2-amine Inhibitors of Dual Leucine Zipper Kinase (DLK, MAP3K12)

Recent data suggest that inhibition of dual leucine zipper kinase (DLK, MAP3K12) has therapeutic potential for treatment of a number of indications ranging from acute neuronal injury to chronic neurodegenerative disease. Thus, high demand exists for selective small molecule DLK inhibitors with favorable drug-like properties and good CNS penetration. Herein we describe a shape-based scaffold hopping approach to convert pyrimidine 1 to a pyrazole core with improved physicochemical properties. We also present the first crystal structures of DLK. By utilizing a combination of property and structure-based design, we identified inhibitor 11, a potent, selective, and brain-penetrant inhibitor of DLK with activity in an in vivo nerve injury model.

Lipid metabolism in patients with chronic renal failure in the predialytic phase

CRF is accompanied by characteristic alterations of lipoprotein metabolism with a retarded catabolism of triglyceride-rich lipoproteins as a prominent feature. Further investigation of the lipoprotein profile of CRF could provide information on the fundamental pathophysiological processes responsible for these disturbances and their possible clinical significance.

Molecular mechanisms of Alzheimer disease protection by the A673T allele of amyloid precursor protein

Pathogenic mutations in the amyloid precursor protein (APP) gene have been described as causing early onset familial Alzheimer disease (AD). We recently identified a rare APP variant encoding an alanine-to-threonine substitution at residue 673 (A673T) that confers protection against development of AD (Jonsson, T., Atwal, J. K., Steinberg, S., Snaedal, J., Jonsson, P. V., Bjornsson, S., Stefansson, H., Sulem, P., Gudbjartsson, D., Maloney, J., Hoyte, K., Gustafson, A., Liu, Y., Lu, Y., Bhangale, T., Graham, R. R., Huttenlocher, J., Bjornsdottir, G., Andreassen, O. A., Jönsson, E. G., Palotie, A., Behrens, T. W., Magnusson, O. T., Kong, A., Thorsteinsdottir, U., Watts, R. J., and Stefansson, K. (2012) Nature 488, 96-99). The Ala-673 residue lies within the β-secretase recognition sequence and is part of the amyloid-β (Aβ) peptide cleavage product (position 2 of Aβ). We previously demonstrated that the A673T substitution makes APP a less favorable substrate for cleavage by BACE1. In follow-up studies, we confirm that A673T APP shows reduced cleavage by BACE1 in transfected mouse primary neurons and in isogenic human induced pluripotent stem cell-derived neurons. Using a biochemical approach, we show that the A673T substitution modulates the catalytic turnover rate (V(max)) of APP by the BACE1 enzyme, without affecting the affinity (K(m)) of the APP substrate for BACE1. We also show a reduced level of Aβ(1-42) aggregation with A2T Aβ peptides, an observation not conserved in Aβ(1-40) peptides. When combined in a ratio of 1:9 Aβ(1-42)/Aβ(1-40) to mimic physiologically relevant mixtures, A2T retains a trend toward slowed aggregation kinetics. Microglial uptake of the mutant Aβ(1-42) peptides correlated with their aggregation level. Cytotoxicity of the mutant Aβ peptides was not dramatically altered. Taken together, our findings demonstrate that A673T, a protective allele of APP, reproducibly reduces amyloidogenic processing of APP and also mildly decreases Aβ aggregation. These effects could together have an additive or even synergistic impact on the risk of developing AD.

Case Studies of Minimizing Nonspecific Inhibitors in HTS Campaigns That Use Assay-Ready Plates

Identifying chemical lead matter by high-throughput screening (HTS) has been a common practice in early stage drug discovery. Evolution of small-molecule library composition to include more drug-like molecules with desirable physical chemical properties combined with improving assay technologies has vastly enhanced the capability of HTS. However, HTS campaigns can still be plagued by false positives arising from nonspecific inhibitors. The generation of assay-ready plates has permitted an incremental advancement to the speed and efficiency of HTS but has the potential to enhance the occurrence of nonspecific inhibitors. A subtle change in the order of reagent addition to the assay-ready plates can greatly alleviate false-positive inhibition. Our case studies with six different kinase and protease targets reveal that this type of inhibition affects targets regardless of enzyme class and is unpredictable based on protein construct or inhibitor chemical scaffold. These case studies support a model where a diversity set of compounds should be tested first for hit rates as a function of order of addition, carrier protein, and relevant mechanistic studies prior to launch of the HTS campaign.

A Phenotype-Based Model for Rational Selection of Novel Targeted Therapies in Treating Aggressive Breast Cancer

BackgroundGlobal transcriptional profiling has facilitated breast cancer research, and has led to analyses of breast cancer phenotypes and clinical outcomes. While gene expression signatures can identify patients with aggressive tumors who require chemotherapy, data that guide drug selection are relatively sparse, generally obtained in clinical trials that treat patients with standard therapies and often limited by small study size. We propose a method that incorporates genomic and in vitro and in vivo preclinical testing of patient tumors to identify optimal and novel therapeutic regimens for individual breast tumors.Methods and FindingsNine independent microarray datasets comprised of 1,723 breast cancer cases were used in a meta-analysis to examine patterns of drug sensitivity predictions. Drug sensitivity signatures were developed based on the Broad Institute Connectivity Map, and applied using binary regression to individual tumor gene expression data. These analyses provide probabilities for each individual tumor's sensitivity to specific drugs, and allows us to identify patterns of drug sensitivity for unique breast cancer phenotypes. We found consistent patterns of drug sensitivity that were specific to individual tumor subtypes. Notably, we discovered that over 80% of basal-like breast cancers were predicted to respond to inhibitors of the phosphatidylinositol 3-kinase pathway and that normal-like tumors were most likely to respond to a heat shock protein 90 inhibitor. Among the more aggressive breast cancer phenotypes, there was a high predicted response to valproic acid (VPA), a histone deacetylase inhibitor. Using a subset of targeted therapeutics that are currently in clinical trials with solid tumors and for which we have drug response signatures, we performed in vitro drug testing on a panel of 18 breast cancer cell lines and found significant correlation between predicted and actual drug sensitivity. Additionally, predicted sensitivity to VPA for specific patient breast tumors was confirmed in vitro and in vivo, using 3-D primary cell culture and orthotopic xenografts generated from the same human tumors for which the predictions were made. These studies highlight VPA as an effective therapy for aggressive breast cancer tumors, and underscore the suitability of our genomic approach to identify optimal targeted therapeutic strategies for women with breast cancer.ConclusionsWe provide a drug sensitivity prediction model using primary tumor gene expression profiles and offer preclinical examples of drug response based on this model. This approach can be used to personalize drug therapy for patients with breast cancer. This will hopefully improve clinical responses for patients while sparing them toxicity from agents that will have no effect on their tumors.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2007.

Oxime derivatives related to AP18: Agonists and antagonists of the TRPA1 receptor

AP18 1 was recently disclosed as an antagonist of the TRPA1 receptor by the research group of Patapoutian. However, no detailed structure-activity relationships around 1 have been disclosed. Thus, a small number of oximes related to AP18 were examined in order to characterize the determinants of TRPA1 activity. Congeners of AP18 were found to possess both agonist and antagonist activity, suggesting that AP18 may behave as a covalent antagonist of the TRPA1 ion-channel.

Third-body abrasive wear challenge of 32 mm conventional and 44 mm highly crosslinked polyethylene liners in a hip simulator model

Hip simulator studies have shown that wear in the polyethylene liners used for total hip replacements increased with the larger-diameter femoral balls and could also be exacerbated by third-body abrasion. However, they also indicated that the more highly cross-linked polyethylene (HXPE) bearings were more wear resistant than conventional polyethylene (CXPE) bearings. Unfortunately the HXPE bearings appeared to be particularly sensitive to adverse wear conditions. One simulator study in particular indicated that poly(methyl methacrylate) (PMMA) debris increased wear sixfold by means of two-body abrasive interactions rather than the supposed third-body abrasion or roughening effects of the Co-Cr surfaces. There has been no confirmation of such novel theories. Therefore the goal of this study was to investigate the sensitivity of large-diameter HXPE bearings to the third-body PMMA wear challenge in a hip simulator model. An orbital hip simulator was used in standard test mode with a physiological load profile. The 32 mm control liners were machined from moulded GUR1050 and gamma irradiated to 35 kGy under nitrogen (CXPE). The 44 mm liners were also from moulded blanks, gamma irradiated to 75 kGy, machined to shape, given a proprietary heat treatment, and sterilized by gas plasma (HXPE). As in the published simulator model, the study was conducted in three phases. In phase 1, all cups were run in standard ('clean') lubricant for 1.5 x 10(6) cycles duration. In phase 2, three CXPE cups and six HXPE cups were run for 2 x 10(6) cycles with a slurry of PMMA particles added to the lubricant. In phase 3, the implants were again run in 'clean' lubricant for 2 x 10(6) cycles duration. In addition, three HXPE cups were run as wear controls for 5.5 x 10(6) cycles duration in clean lubricant. In phase-1, the HXPE liners demonstrated twelvefold reduced wear compared with the CXPE controls. The 32 mm and 44 mm Co-Cr balls were judged of comparable roughnesses. However, the surface finish of HXPE liners was superior to that of CXPE liners. In phase-2 abrasion, wear rates increased sixfold and eighty-fold for CXPE and HXPE bearings respectively. These data confirmed that HXPE bearings were particularly sensitive to 'severe' test modes. The Co-Cr balls revealed numerous surface patches representing transferred PMMA with average transient roughness increased to 25 nm and 212 nm for the 32 mm and 44 mm balls respectively. These PMMA patches produced an aggressive two-body abrasion wear of the polyethylene. After cleaning, the ball roughness returned to near normal. Therefore the Co-Cr roughness was not an issue in this severe test mode. In phase 3, the wear decreased to near the index values of phase 1, while liner roughness dropped by more than 90 per cent. The control CXPE liners now demonstrated twice the wear of the HXPE, as would be predicted comparing the diameter and cross-linking algorithms. No previous study has correlated polyethylene roughness profiles to wear performance. In phase 2, PMMA abrasion created significant damage to the polyethylene surfaces. The average roughness Sa of CXPE liners increased to 3.6 microm, a twenty-four-fold increase with some scratches up to 40 microm deep. The HXPE roughness also increased but only to 1.5 microm, a ninefold increase. The scratch indices Sz and Sp for HXPE surfaces were also 50 per cent less severe than on CXPE surfaces. However, within 2 x 10(6) cycles duration of phase 3, all liners had recovered to virtually their original surface finish in phase 1. In all test phases, the surface finish of the HXPE liners remained superior to control liners. These experimental data confirmed many of the results from the previous simulator study with the PMMA abrasion models. Thus the 44 mm liners appeared an excellent clinical alternative to the smaller ball designs used in total hip replacements.

Myocardial scintigraphy as a supplementary diagnostic tool in heart disease

Myocardial scintigraphy with cesium-131 and thallium-201 was performed in 191 patients. Previous myocardial infarctions localized to the anterior and lateral wall of the left ventricle were correctly diagnosed with both radionuclides. Inferior and posterior infarctions were only detected when thallium was used. In patients with non-informative ECG changes like bundle branch block, non-specific ST-T changes or with atypical symptoms, myocardial imaging made an essential contribution to the establishment of a correct diagnosis. The potential value of myocardial imaging in patients with valvular heart disease and in cardiomyopathy is described.

Cardaic arrhythmias in chloral hydrate poisoning

In three patients admitted to hospital after ingestion of an overdose of chloral hydrate, the ECG showed supreventricular and ventricular tachyarrhythmias. The possible mechanism for the arrhythmias may be an enhanced automaticity of supraventricular and ventricular pacemaker cells caused by metabolites of chloral hydrate. The ventricular arrhythmia responded to i.v. treatment with lignocaine in one patient, and to phenytoin in another in whom lignocaine failed to restore a normal sinus rhythm.

The use of thallium-201 myocardial scintigraphy for the diagnosis of previous infarction

The ability of thallium-201 scintigraphy to detect previous infarction (greater than 6 months ago) was studied in 43 patients with coronary artery disease, 39 with valvular heart disease, and 5 with cardiomyopathy or myocarditis. All patients had undergone selective coronary arteriography and left ventricular angiography. Thallium-201 scintigraphy at rest proved a very sensitive method for detecting previous infarction, also clinically silent. Scintigraphy was more sensitive than a recent ECG. However, scintigraphy can give falsely positive results.

Diagnosis and management of acute aortic dissection, clinical and radiological follow-up

A clinical series of acute aortic dissections is presented. Twenty cases were of type A and 10 of type B. Acute severe chest pain was common, in type A also blood pressure difference between the arms and aortic regurgitation. The diagnosis was established by echocardiography, computerized tomography and/or aortography. Antihypertensive therapy was instituted immediately after diagnosis and was in type A cases followed by acute surgery unless definite contraindications existed. Of 14 surgically treated type A patients 13 survived the operation. On follow-up 1.5-3.5 years later, 12 patients were still alive and doing well, but the false channel remained open in all cases where it had not been resected totally. Only one of six conservatively treated type A patients survived. Type B dissections were operated on only if conservative therapy failed. Four of five conservatively and two of five surgically treated type B patients survived.

Reduced high density lipoproteins as a risk factor after acute myocardial infarction

In a group of normocholesterolemic, non-diabetic middle-aged males surviving an acute myocardial infarction for 4 +/- 2 years (mean +/- SD), we have previously described a low apolipoprotein A-I and a deficient fibrinolytic activity as two major characteristics. In the present study we have followed morbidity and mortality risk factors for five years in these males. Mortality was 40% in a hypertensive group and 16% in a normotensive group. In the normotensive group mortality was related to reinfarction. Furthermore, patients with a poor prognosis in the normotensive group had lower high density lipoprotein (HDL) cholesterol and lower apolipoprotein A-I concentration in plasma than patients with a good prognosis. Unexpectedly, in the hypertensive group death was related to a low (p less than 0.05) cortisol concentration in urine. It is concluded that a low HDL level may be a bad prognostic sign in males who have sustained an acute myocardial infarction and show no evidence of other risk factors, such as diabetes, hypercholesterolemia or hypertension.

Plasma lipoproteins and fatty acid composition during a moderate eicosapentaenoic acid diet

The effect of a diet rich in marine fatty acids, especially eicosapentaenoic acid, on plasma lipids (total plasma cholesterol, HDL cholesterol, total triglycerides and apolipoproteins A and B) and fatty acid composition in plasma phosphatidylcholine (PC) was studied in 10 healthy men. They were maintained for 11 weeks on their normal diet which was partly replaced by 150-200 g of fatty fish per day. In the same individuals this diet had previously caused a delay in primary haemostasis and a decrease in platelet aggregability similar to that caused by acetylsalicylic acid, a known inhibitor of thromboxane A2 formation. Apart from its effect on haemostasis, the fish diet substantially reduced serum triglycerides (by 43%, p less than 0.01) but caused no changes in total plasma or HDL cholesterol or apolipoproteins A and B. After three weeks on the diet the proportion of plasma PC omega-3 polyunsaturated fatty acids increased (C20:5 and C22:6) and omega-6 fatty acids decreased (C18:2 and C20:3). The relative plasma PC content of arachidonic acid was unaffected throughout. These alterations in plasma PC fatty acid composition were principally in accordance with those seen in platelet membrane PC. There was a linear correlation between the content of omega-3 and of omega-6 fatty acids in plasma PC with that of platelet PC as well as in predominate individual fatty acids of the two series. Six weeks after the volunteers had resumed their usual diet, total triglycerides and the fatty acid composition of plasma PC had returned to the original state.