Discovery of GNE-149 as a Full Antagonist and Efficient Degrader of Estrogen Receptor alpha for ER+ Breast Cancer

Estrogen receptor alpha (ERα) is a well-validated drug target for ER-positive (ER+) breast cancer. Fulvestrant is FDA-approved to treat ER+ breast cancer and works through two mechanisms-as a full antagonist and selective estrogen receptor degrader (SERD)-but lacks oral bioavailability. Thus, we envisioned a "best-in-class" molecule with the same dual mechanisms as fulvestrant, but with significant oral exposure. Through lead optimization, we discovered a tool molecule 12 (GNE-149) with improved degradation and antiproliferative activity in both MCF7 and T47D cells. To illustrate the binding mode and key interactions of this scaffold with ERα, we obtained a cocrystal structure of 6 that showed ionic interaction of azetidine with Asp351 residue. Importantly, 12 showed favorable metabolic stability and good oral exposure. 12 exhibited antagonist effect in the uterus and demonstrated robust dose-dependent efficacy in xenograft models.

Implementing receiver-driven handoffs to the emergency department to reduce miscommunication

BACKGROUND

Miscommunications during care transfers are a leading cause of medical errors. Recent consensus-based recommendations to standardise information transfer from outpatient clinics to the emergency department (ED) have not been formally evaluated. We sought to determine whether a receiver-driven structured handoff intervention is associated with 1) increased inclusion of standardised elements; 2) reduced miscommunications and 3) increased perceived quality, safety and efficiency.

METHODS

We conducted a prospective intervention study in a paediatric ED and affiliated clinics in 2016-2018. We developed a bundled handoff intervention included a standard template, receiver training, awareness campaign and iterative feedback. We assessed a random sample of audio-recorded handoffs and associated medical records to measure rates of inclusion of standardised elements and rate of miscommunications. We surveyed key stakeholders pre-intervention and post-intervention to assess perceptions of quality, safety and efficiency of the handoff process.

RESULTS

Across 162 handoffs, implementation of a receiver-driven intervention was associated with significantly increased inclusion of important elements, including illness severity (46% vs 77%), tasks completed (64% vs 83%), expectations (61% vs 76%), pending tests (0% vs 64%), contingency plans (0% vs 54%), detailed callback request (7% vs 81%) and synthesis (2% vs 73%). Miscommunications decreased from 48% to 26%, a relative reduction of 23% (95% CI -39% to -7%). Perceptions of quality (35% vs 59%), safety (43% vs 73%) and efficiency (17% vs 72%) improved significantly post-intervention.

CONCLUSIONS

Implementation of a receiver-driven intervention to standardise clinic-to-ED handoffs was associated with improved communication quality. These findings suggest that expanded implementation of similar programmes may significantly improve the care of patients transferred to the paediatric ED.

Abstract B23: Crucial deubiquitinases in cancer cell survival

Deubiquitinases (DUBs) are enzymes that proteolytically cleave ubiquitin from substrates. Substrates include oncogenes, tumor suppressors and polyubiquitinated proteins marked for degradation by the proteasome. Ubiquitin specific peptidase-7 (USP7) deubiquitinates MDM2 (an oncogene). MDM2 is a ligase that ubiquitinates p53 (a tumor suppressor protein), targeting it for proteosomal degradation. As such, USP7 is a promising cancer target because its inhibition stabilizes p53 and thereby promotes apoptosis and cell cycle arrest, processes that are often deregulated in tumors (Nicholson and Suresh Kumar, 2011). We found that USP7 was selectively druggable following a fragment-based lead discovery effort to obtain USP7 antagonists. Cellular and xenograft studies confirm that inhibiting USP7 activity stabilized p53 levels and p53-downstream target, p21. Additionally, normal primary and p53-null cells were less sensitive than the corresponding p53-WT cancer cells to USP7 inhibition.

To investigate whether other DUBs are involved in cancer cell survival, we carried out a drop-out CRISPR screen using a pooled DUB library in HCT116 and A549 cells. Out of the approximately 100 DUBs targeted, nine, including USP7, were found to affect cell viability. These hits were validated using siRNA-mediated knockdown in cancer cell lines (A549, HCT116, MCF7). Three DUBs that robustly decreased cell proliferation were further tested in normal cells (Human Mammary Epithelial Cells and Human Bronchial Epithelial Cells). DUB protein expression levels and activity were also determined. In general, DUB expression levels, activity and knockdown efficiency were higher in cancer cells compared to normal cells. Collectively, our studies support the hypothesis that USP7 inhibition may be an efficacious strategy to promote cancer cell death. Furthermore, there are other DUBs that should be considered as novel cancer targets.

Citation Format: Lorna Kategaya, Trinna Cuellar, Ben Haley, Jinfeng Liu, Andy Tran, Yi Cao, David Stokoe, Mark McCleland, Beth Blackwood, Sharon Yee, Joy Drobnick, Jake Drummond, James Ernst, Michael Kwok, Cuong Ly, Richard Pastor, Paola Di Lello, Chudi Ndubaku, Robert Blake, Vickie Tsui, Jeremy Murray, Till Maurer, Ingrid Wertz. Crucial deubiquitinases in cancer cell survival. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Targeting the Vulnerabilities of Cancer; May 16-19, 2016; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(1_Suppl):Abstract nr B23.

Precisely parameterized experimental and computational models of tissue organization

Patterns of cellular organization in diverse tissues frequently display a complex geometry and topology tightly related to the tissue function. Progressive disorganization of tissue morphology can lead to pathologic remodeling, necessitating the development of experimental and theoretical methods of analysis of the tolerance of normal tissue function to structural alterations. A systematic way to investigate the relationship of diverse cell organization to tissue function is to engineer two-dimensional cell monolayers replicating key aspects of the in vivo tissue architecture. However, it is still not clear how this can be accomplished on a tissue level scale in a parameterized fashion, allowing for a mathematically precise definition of the model tissue organization and properties down to a cellular scale with a parameter dependent gradual change in model tissue organization. Here, we describe and use a method of designing precisely parameterized, geometrically complex patterns that are then used to control cell alignment and communication of model tissues. We demonstrate direct application of this method to guiding the growth of cardiac cell cultures and developing mathematical models of cell function that correspond to the underlying experimental patterns. Several anisotropic patterned cultures spanning a broad range of multicellular organization, mimicking the cardiac tissue organization of different regions of the heart, were found to be similar to each other and to isotropic cell monolayers in terms of local cell-cell interactions, reflected in similar confluency, morphology and connexin-43 expression. However, in agreement with the model predictions, different anisotropic patterns of cell organization, paralleling in vivo alterations of cardiac tissue morphology, resulted in variable and novel functional responses with important implications for the initiation and maintenance of cardiac arrhythmias. We conclude that variations of tissue geometry and topology can dramatically affect cardiac tissue function even if the constituent cells are themselves similar, and that the proposed method can provide a general strategy to experimentally and computationally investigate when such variation can lead to impaired tissue function.

Verification of cardiac mechanics software: benchmark problems and solutions for testing active and passive material behaviour

Models of cardiac mechanics are increasingly used to investigate cardiac physiology. These models are characterized by a high level of complexity, including the particular anisotropic material properties of biological tissue and the actively contracting material. A large number of independent simulation codes have been developed, but a consistent way of verifying the accuracy and replicability of simulations is lacking. To aid in the verification of current and future cardiac mechanics solvers, this study provides three benchmark problems for cardiac mechanics. These benchmark problems test the ability to accurately simulate pressure-type forces that depend on the deformed objects geometry, anisotropic and spatially varying material properties similar to those seen in the left ventricle and active contractile forces. The benchmark was solved by 11 different groups to generate consensus solutions, with typical differences in higher-resolution solutions at approximately 0.5%, and consistent results between linear, quadratic and cubic finite elements as well as different approaches to simulating incompressible materials. Online tools and solutions are made available to allow these tests to be effectively used in verification of future cardiac mechanics software.

Sustained perceptual invisibility of solid shapes following contour adaptation to partial outlines

Contour adaptation (CA) is a recently described paradigm that renders otherwise salient visual stimuli temporarily perceptually invisible. Here we investigate whether this illusion can be exploited to study visual awareness. We found that CA can induce seconds of sustained invisibility following similarly long periods of uninterrupted adaptation. Furthermore, even fragmented adaptors are capable of producing CA, with the strength of CA increasing monotonically as the adaptors encompass a greater fraction of the stimulus outline. However, different types of adaptor patterns, such as distinctive shapes or illusory contours, produce equivalent levels of CA suggesting that the main determinants of CA are low-level stimulus characteristics, with minimal modulation by higher-order visual processes. Taken together, our results indicate that CA has desirable properties for studying visual awareness, including the production of prolonged periods of perceptual dissociation from stimulation as well as parametric dependencies of that dissociation on a host of stimulus parameters.

Mechanistic inquiry into the role of tissue remodeling in fibrotic lesions in human atrial fibrillation

Atrial fibrillation (AF), the most common arrhythmia in humans, is initiated when triggered activity from the pulmonary veins propagates into atrial tissue and degrades into reentrant activity. Although experimental and clinical findings show a correlation between atrial fibrosis and AF, the causal relationship between the two remains elusive. This study used an array of 3D computational models with different representations of fibrosis based on a patient-specific atrial geometry with accurate fibrotic distribution to determine the mechanisms by which fibrosis underlies the degradation of a pulmonary vein ectopic beat into AF. Fibrotic lesions in models were represented with combinations of: gap junction remodeling; collagen deposition; and myofibroblast proliferation with electrotonic or paracrine effects on neighboring myocytes. The study found that the occurrence of gap junction remodeling and the subsequent conduction slowing in the fibrotic lesions was a necessary but not sufficient condition for AF development, whereas myofibroblast proliferation and the subsequent electrophysiological effect on neighboring myocytes within the fibrotic lesions was the sufficient condition necessary for reentry formation. Collagen did not alter the arrhythmogenic outcome resulting from the other fibrosis components. Reentrant circuits formed throughout the noncontiguous fibrotic lesions, without anchoring to a specific fibrotic lesion.

A cellular model for sporadic ALS using patient-derived induced pluripotent stem cells

Development of therapeutics for genetically complex neurodegenerative diseases such as sporadic amyotrophic lateral sclerosis (ALS) has largely been hampered by lack of relevant disease models. Reprogramming of sporadic ALS patients' fibroblasts into induced pluripotent stem cells (iPSC) and differentiation into affected neurons that show a disease phenotype could provide a cellular model for disease mechanism studies and drug discovery. Here we report the reprogramming to pluripotency of fibroblasts from a large cohort of healthy controls and ALS patients and their differentiation into motor neurons. We demonstrate that motor neurons derived from three sALS patients show de novo TDP-43 aggregation and that the aggregates recapitulate pathology in postmortem tissue from one of the same patients from which the iPSC were derived. We configured a high-content chemical screen using the TDP-43 aggregate endpoint both in lower motor neurons and upper motor neuron like cells and identified FDA-approved small molecule modulators including Digoxin demonstrating the feasibility of patient-derived iPSC-based disease modeling for drug screening.

A novel illusion of bars made from triangles

A repetitive pattern of a triangular luminance profile may be perceived as a triangular-wave grating or as a square-wave grating. This illusion may reflect the operation of cortical phase-selective mechanisms that are biased toward particular phase relations and favor abrupt luminance gradients.

Squatting after primary unilateral total knee arthroplasty: a pilot study examining differences between genders

OBJECTIVE

To compare the weight bearing of men and women during standing and squatting after knee replacement surgery for osteoarthritis.

DESIGN

Two-group, single-surgeon study with patients selected consecutively through a sample of convenience. Patients evaluated at first outpatient rehabilitation visit and at discharge from outpatient services.

SETTING

Outpatient orthopedic institute.

PARTICIPANTS

Seventeen women (average age, 71 years) and 16 men (69 years) who underwent primary unilateral knee replacement for osteoarthritis.

MAIN OUTCOME MEASUREMENTS

Percentage of body weight placed over the surgical limb during standing and during 30° and 60° squats.

RESULTS

The men placed a greater percentage of body weight over the surgical limb during the 30° and 60° squats, both at the initial visit and at discharge. Both women and men had similar improvements with all dependent measurements.

CONCLUSION

The magnitude of change for women and men was similar, yet percentage of body weight placed over the surgical limb in women was less than in men at the initial visit and did not match that in their male counterparts by discharge.

Closed-chain exercise after simultaneous bilateral knee replacement surgery: a case report

The purpose of this case report was to present a method for assessing entire lower extremity performance and describe a Medical Exercise Therapy (MET) training program early after simultaneous bilateral total knee replacement (TKR). We also documented perceived function, mobility, and weight-bearing ability during functional tasks. The patient was a 50-year-old male who underwent a simultaneous bilateral procedure and began physical therapy (PT) 16 days postsurgery. Lower extremity performance (weight, repetitions, and load*volume) was assessed weekly using a one-legged horizontal press. Perceived physical abilities, mobility, and body weight placed over each limb during a sit to stand and a squat at two different flexion angles were assessed. At discharge load*volume for the weakest limb was 87% of the strongest side. At discharge, sit-to-stand, and 30 and 60 degree squat asymmetry ranged from 4% to 6%. Perceived abilities and mobility improved from initial visit to discharge. The patient was able to tolerate the closed-chain assessment of lower extremity performance and MET training program early after surgery. The patient made improvements in all functional tests and more importantly maintained a fairly equal distribution of body weight over both limbs during functional activities.