HTS driven by fluorescence lifetime detection of FRET identifies activators and inhibitors of cardiac myosin

Small molecules that bind to allosteric sites on target proteins to alter protein function are highly sought in drug discovery. High-throughput screening (HTS) assays are needed to facilitate the direct discovery of allosterically active compounds. We have developed technology for high-throughput time-resolved fluorescence lifetime detection of fluorescence resonance energy transfer (FRET), which enables the detection of allosteric modulators by monitoring changes in protein structure. We tested this approach at the industrial scale by adapting an allosteric FRET sensor of cardiac myosin to high-throughput screening (HTS), based on technology provided by Photonic Pharma and the University of Minnesota, and then used the sensor to screen 1.6 million compounds in the HTS facility at Bristol Myers Squibb. The results identified allosteric activators and inhibitors of cardiac myosin that do not compete with ATP binding, demonstrating high potential for FLT-based drug discovery.

Heart failure across the range of preserved ejection fraction in United States clinical practice

Introduction

Recent clinical trials of heart failure with preserved ejection fraction (HFpEF) have observed varying patient profiles by ejection fraction (EF), with attenuation of treatment benefits as EF increases. In routine clinical practice, the degree to which patients hospitalized for HF with EF≥60% may differ from those with lower EF is unknown.

Purpose

To compare patient characteristics, treatment patterns, and clinical outcomes across the range of EF among patients hospitalized for HFpEF.

Methods

Using the Humedica electronic medical records database between Jan 2010 and Dec 2020, patients hospitalized for a primary diagnosis of HF with EF>40% and who were haemodynamically stable at admission, without concurrent acute coronary syndrome or end-stage renal disease, and treated with intravenous (IV) diuretic agents within 48 h of admission were identified. Patient characteristics, treatment patterns, and clinical outcomes were compared by EF ranges of 41–49%, 50–59%, and ≥60%.

Results

Of 47,026 patients hospitalized with HFpEF, 6,335 (13%) had EF 41–49%, 18,603 (40%) had EF 50–59%, and 22,088 (47%) had EF≥60%. Across all 3 groups, patients were similar with respect to age (median 77 years for each group), race (83–84% White, 12–13% Black), systolic blood pressure (137–138 mmHg at admission), and eGFR (63–64 mL/min/1.73 m2 at admission). With progressively higher EF group, the proportion of women increased (45% vs 54% vs 65%) and median NT-proBNP decreased (4,221 vs 2,945 vs 2,234 pg/mL). Patients with EF ≥60% had the lowest rates of coronary artery disease and atrial fibrillation, and the highest rates of chronic pulmonary disease (Figure 1, Panel A). Discharge medications were generally similar, with exception of less beta-blocker use and more calcium channel blocker use among those with EF ≥60% (Figure 1, Panel B). Discharge use of angiotensin receptor-neprilysin inhibitor and sodium glucose cotransporter-2 inhibitor therapies were each <1% in all groups. Hospital length of stay (median 4 days for each group) and in-hospital mortality (1.1–1.3%) were similar across groups, but rates of in-hospital acute respiratory failure were higher among patients with EF ≥60% (27% vs 230-25% for lower EF groups). Rates of 30-day and 12-month post-discharge clinical events were high irrespective of EF, without meaningful differences between groups (Figure 2).

Conclusion

In a contemporary real-world population of US patients hospitalized for HF with EF >40%, nearly half had an EF≥60%. While clinical profiles and discharge medications varied, post-discharge outcomes were similarly poor irrespective of EF. There remain important opportunities to improve the care and outcomes for patients with HF across the range of preserved ejection fraction.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): MyoKardia, Inc., a wholly owned subsidiary of Bristol Myers Squibb

Models help set ecosystem service baselines for restoration assessment

Coastal suburban watersheds are under heavy pressure from human activity. This pressure has yielded an extensive effort to protect, mitigate, and restore watershed ecosystem services. Assessment of restoration investments would be greatly improved by a standard approach for estimating change in ecosystem service production combined with a well-defined baseline for assessment of restoration effects. Here we take a model-based approach to both objectives by applying two established ecosystem service models in a representative coastal watershed. This watershed has undergone extensive suburbanization resulting in a loss of ecosystem services, which has resulted in heavy restoration investments. We used models to estimate loss of the ecosystem services; clean air, clean water, stable climate, and water storage resulting from suburbanization. We then applied these model-based estimates as a baseline for assessment of restoration focusing on the appropriate restoration scale and considering downstream watershed impacts. The results suggest that losses of ecosystem services, such as flood water storage, from suburbanization have been extensive since 2001, but a comparison of restoration value suggests that restoration has been effective in recouping ecosystem services in some but not all local regions suggesting there are trade-offs to be made in these efforts. These benefits were most evident for the services of clean water and water storage. Models can inform decisions by clarifying what has been lost and estimating what can be regained through restoration action. The former sets a baseline for the latter and allows for a functional equivalency approach to assessment.

Is lumican responsible for the low angiogenetic potential of the adult mammalian heart?

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): AIRC

Introduction

Adult mammals fail to regenerate the myocardium after ischemic injury (1). Different strategies to achieve myocardial regeneration have been considered including reactivation of progenitor cell populations, cell replacement therapies, cell reprograming and molecules able to stimulate cardiomyocyte proliferation (2). None of these approaches has been so far successful. The supply of nutrients and oxygen to the myocardium after the occlusion of a coronary artery depends on pre-existing and newly formed collateral vessels (3). The relevance of revascularization in the context of cardiac regeneration is suggested by the evidence that angiogenesis precedes cardiomyocyte proliferation in a model of neonatal heart injury (4). Our laboratory has recently demonstrated that the heart has a low angiogenetic potential (5). To what extent this is responsible for the poor regenerative capacity of the heart remains to be determined. Thus, understanding the mechanisms blocking angiogenesis in the adult heart could lead to the development of efficient strategies to promote cardiac revascularization and regeneration.

Purpose

Our purpose is to understand the mechanisms responsible for the low angiogenic potential of the adult mammalian heart. In particular, we designed a proteomic approach to detect differences in the composition of the perivascular extracellular matrix between the neonatal (angiogenic) with and the adult (not angiogenic) heart.

Methods and Results

We adopted an in vivo biotinylation strategy to label vascular extracellular proteins in vivo, followed by protein identification by mass spectrometry. A reactive derivative of biotin was systemically injected in both neonatal and adult mice (n=4) to label vascular and peri-vascular extracellular proteins. Biotinylated proteins were purified from total hearts by streptavidin-conjugated beads, eluted, and digested with trypsin. The resulting peptides were analyzed by LC-MS/MS. Among the differentially expressed proteins, we identified lumican and its receptor, integrin beta-1. This ligand-receptor pair is known to impair tube formation by endothelial cells and to interfere with both expression and activity of matrix metalloproteinases (MMPs) in vitro (6). Western blot and gene expression analysis confirmed up-regulation of lumican in the adult compared to neonatal heart, as well as a different glycosylation pattern. Lumican knock-out both ex vivo and in vivo resulted in increased vessel density. On the other hand, overexpression of lumican impaired the proliferative capacity of cardiac endothelial cells. Finally, MMP-14 activity was inhibited by adult, but not neonatal cardiac extract.

Conclusions

In vivo proteomic analysis identified lumican as a major contributor of the low angiogenic potential of the adult mammalian heart. These results point to lumican silencing as a promising strategy to achieve cardiac revascularization.

A Wireless Wearable Doppler Ultrasound Detects Changing Stroke Volume: Proof-of-Principle Comparison with Trans-Esophageal Echocardiography during Coronary Bypass Surgery

BACKGROUND

A novel, wireless, ultrasound biosensor that adheres to the neck and measures real-time Doppler of the carotid artery may be a useful functional hemodynamic monitor. A unique experimental set-up during elective coronary artery bypass surgery is described as a means to compare the wearable Doppler to trans-esophageal echocardiography (TEE).

METHODS

A total of two representative patients were studied at baseline and during Trendelenburg position. Carotid Doppler spectra from the wearable ultrasound and TEE were synchronously captured. Areas under the receiver operator curve (AUROC) were performed to assess the accuracy of changing common carotid artery velocity time integral (ccVTI∆) at detecting a clinically significant change in stroke volume (SV∆).

RESULTS

Synchronously measuring and comparing Doppler spectra from the wearable ultrasound and TEE is feasible during Trendelenburg positioning. In two representative cardiac surgical patients, the ccVTI∆ accurately detected a clinically significant SV∆ with AUROCs of 0.89, 0.91, and 0.95 when single-beat, 3-consecutive beat and 10-consecutive beat averages were assessed, respectively.

CONCLUSION

In this proof-of-principle research communication, a wearable Doppler ultrasound system is successfully compared to TEE. Preliminary data suggests that the diagnostic accuracy of carotid Doppler ultrasonography at detecting clinically significant SV∆ is enhanced by averaging more cardiac cycles.

The Doppler shock index measured by a wearable ultrasound patch accurately detects moderate-to-severe central hypovolemia during lower body negative pressure

OBJECTIVE

Moderate-to-severe hemorrhage is a life-threatening condition, which is challenging to detect in a timely fashion using traditional vital signs because of the human body's robust physiologic compensatory mechanisms. Measuring and trending blood flow could improve diagnosis of clinically significant exsanguination. A lightweight, wireless, wearable Doppler ultrasound patch that captures and trends blood flow velocity could enhance hemorrhage detection.

METHODS

In 11 healthy volunteers undergoing simulated hemorrhage and resuscitation during graded lower body negative pressure (LBNP) and release, we studied the relationship between stroke volume (SV) and common carotid artery velocity time integral (VTI) and corrected flow time (FTc). We assessed the diagnostic accuracy of 2 variations of a novel metric, the Doppler shock index (ie, the DSIVTI and DSIFTc), at capturing moderate-to-severe central hypovolemia defined as a 30% reduction in SV. The DSIVTI and DSIFTc are calculated as the heart rate divided by either the VTI or FTc, respectively.

RESULTS

A total of 17,822 cardiac cycles were analyzed across 22 LBNP protocols. The average SV reduction to the lowest tolerated LBNP stage was 40%; there was no clinically significant fall in the mean arterial pressure. Correlations between changing SV and the common carotid artery VTI and FTc were strong (R 2 of 0.87, respectively) and concordant. The DSIVTI and DSIFTc accurately detected moderate-to-severe central hypovolemia with values for the area under the receiver operator curves of 0.96 and 0.97, respectively.

CONCLUSION

In a human model of hemorrhage and resuscitation, measures from a wearable Doppler ultrasound patch correlated strongly with SV and identified moderate-to-severe central hypovolemia with excellent diagnostic accuracy.

Seroprevalence of SARS-CoV-2 infection in healthcare workers in a large teaching hospital in the North West of England: a period prevalence survey

OBJECTIVES

Since its emergence in late 2019, SARS-CoV-2 has caused a global pandemic that has significantly challenged healthcare systems. Healthcare workers have previously been shown to have experienced higher rates of infection than the general population. We aimed to assess the extent of infection in staff working in our healthcare setting.

DESIGN

A retrospective analysis of antibody results, compared with staff demographic data, and exposure to patients with COVID-19 infection.

SETTING

A large teaching hospital in the North West of England.

PARTICIPANTS

4474 staff in diverse clinical and non-patient facing roles who volunteered for SARS-CoV-2 antibody testing by the Roche Elecsys assay between 29 May and 4 July 2020.

RESULTS

Seroprevalence was 17.4%. Higher rates were seen in Asian/Asian British (OR 1.61, 95% CI 1.27 to 2.04) and Black/Black British (OR 2.08, 95% CI 1.25 to 3.45) staff. Staff working in any clinical location were more likely to be seropositive (OR 2.68, 95% 2.27 to 3.15). Staff were at an increased risk of seropositivity as the 'per 100 COVID-19 bed-days change' increased in the clinical area in which they worked (OR 1.12, 95% 1.10 to 1.14). Staff working in critical care were no more likely to have detectable antibodies than staff working in non-clinical areas. Symptoms compatible with COVID-19 were reported in 41.8% and antibodies were detected in 30.7% of these individuals. In staff who reported no symptoms, antibodies were detected in 7.7%. In all staff who had detectable antibodies, 25.2% reported no symptoms.

CONCLUSIONS

Staff working in clinical areas where patients with COVID-19 were nursed were more likely to have detectable antibodies. The relationship between seropositivity in healthcare workers and the increase in 'per 100 COVID-19 bed-days' of the area in which they worked, although statistically significant, was weak, suggesting other contributing factors to the risk profile. Of staff with detectable antibodies and therefore evidence of prior infection, a quarter self-reported that they had experienced no compatible symptoms. This has implications for potential unrecorded transmission in both staff and patients.

Micro-premature infants in New Jersey show improved mortality and morbidity from 2000-2018

BACKGROUND

Micro-premature newborns, gestational age (GA) ≤ 25 weeks, have high rates of mortality and morbidity. Literature has shown improving outcomes for extremely low gestational age newborns (ELGANs) GA ≤ 29 weeks, but few studies have addressed outcomes of ELGANs ≤ 25 weeks.

OBJECTIVE

To evaluate the trends in outcomes for ELGANs born in New Jersey, from 2000 to 2018 and to compare two subgroups: GA 23 to 25 weeks (E1) and GA 26 to 29 weeks (E2).

METHODS

Thirteen NICUs in NJ submitted de-identified data. Outcomes for mortality and morbidity were calculated.

RESULTS

Data from 12,707 infants represents the majority of ELGANs born in NJ from 2000 to 2018. There were 3,957 in the E1 group and 8,750 in the E2 group. Mortality decreased significantly in both groups; E1, 43.2% to 30.2% and E2, 7.6% to 4.5% over the 19 years. The decline in E1 was significantly greater than in E2. Most morbidities also showed significant improvement over time in both groups. Survival without morbidity increased from 14.5% to 30.7% in E1s and 47.2% to 69.9% in E2s. Similar findings held for 501-750 and 751-1000g birth weight strata.

CONCLUSIONS

Significant declines in both mortality and morbidity have occurred in ELGANs over the last two decades. These rates of improvements for the more immature ELGANs of GA 230 to 256 weeks were greater than for the more mature group in several outcomes. While the rates of morbidity and mortality remain high, these results validate current efforts to support the micro-premature newborn.

Taurine Analysis in Milk and Infant Formulae by Liquid Chromatography: Collaborative Study

A collaborative study was conducted on a liquid chromatographic (LC) method for determination of taurine in infant formula and milk powders. Twenty laboratories participated in the analysis of 8 blind duplicates over the range of approximately 3–60 mg/100 g sample. The method involved protein removal, conversion to the dansyl-derivative, and isocratic LC separation with UV and/or fluorescence detection. Following outlier treatment, overall mean RSDR has been estimated at 7.00% for sup. plemented products with a HORRAT value of 1.1. The poorer precision at endogenous levels establishes a lower limit of determination of about 5 mg/100 g. An overall mean RSDr:RSDR value of 0.7 for all products demonstrated acceptable performance.

Sinister right-handedness provides Canadian-born Major League Baseball players with an offensive advantage: A further test of the hockey influence on batting hypothesis

Recent research has shown Major League Baseball (MLB) players that bat left-handed and throw right-handed, otherwise known as sinister right-handers, are more likely to have a career batting average (BA) of .299 or higher compared to players with other combinations of batting and throwing handedness. Moreover, possibly owing to early exposure to hockey, Canadian-born MLB players have an increased propensity to be sinister right-handers, however, it has yet to be determined whether this provides a relative offensive performance advantage compared to players born in other countries. Using the largest archival dataset of MLB statistics available, the present study examined the independent influence of batting (i.e., left, right, switch) and throwing (i.e., left, right) handedness combinations and country/region of origin (i.e., Canada, USA, Latin America, Asia, Other) on several indices of offensive performance including BA, slugging percentage (SLG), on-base plus slugging (OPS), on-base plus slugging plus (OPS+), home runs (HR), runs batted in (RBI), strikeouts (SO) and wins above replacement (WAR). Mediation models were also computed to examine whether birthplace influences offensive performance through handedness. Examination of all recorded MLB batters revealed that batting left, regardless of throwing handedness, confers an offensive performance advantage. Since the inception of the MLB, the relative proportion of Canadian-born sinister right-handers is at least two times greater than players from other regions, although being Canadian-born does not provide a direct offensive advantage. Rather, results showed evidence of a significant indirect effect in that being Canadian-born increases the odds of being a sinister right-hander and in turn leads to greater performance across each offensive performance statistic. Collectively, findings provide further support for the hockey influence on batting hypothesis and suggest this effect extends to offensive performance.

P87 Spinal fractures incurred by a fall from standing height

Objectives

Falls from standing are an important cause of vertebral fractures, particularly in the elderly. They are associated with significant morbidity and long-term mortality. The aim of this study was to determine the treatment and outcomes, in a single centre, of managing spinal fractures due to falls from standing height.

Design

Retrospective case note review of patients with a fracture sustained due to a fall from standing (2011–2016 inclusive).

Subjects

229 patients with average age 76.6±14.5 years; 134 (58.5%) female.

Methods

Patients were identified from the Trauma Audit and Research Network database. Case notes were reviewed for demographics, treatment details and outcome at 6 months post-admission.

Results

1408 patients were admitted with spinal fractures of which 229 (16.3%) sustained a fall from standing height. Two hundred and eighty-three fractures were identified in the 229 patients, which were distributed in the cervical (n=140), thoracic (n=65) and lumbar (n=78) spine. The average ISS score was 9.7±5.4. Twenty-three (10.0%) patients had either incomplete or complete spinal cord injury. Fifty-six (24.5%) patients underwent surgical intervention. Forty-three patients (18.7%) died within 6 months and increasing age and Charlson co-morbidity score were associated with higher mortality.

Conclusions

Falls from standing comprise a large portion of the spinal service emergency workload. They are associated with a high 6 month mortality similar to other fragility fractures experienced by the elderly.

Better Respiratory Education and Treatment Help Empower (BREATHE) study: Methodology and baseline characteristics of a randomized controlled trial testing a transitional care program to improve patient-centered care delivery among chronic obstructive pulmonary disease patients

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of hospitalizations. Interventional studies focusing on the hospital-to-home transition for COPD patients are few. In the BREATHE (Better Respiratory Education and Treatment Help Empower) study, we developed and tested a patient and family-centered transitional care program that helps prepare hospitalized COPD patients and their family caregivers to manage COPD at home.

METHODS

In the study's initial phase, we co-developed the BREATHE transitional care program with COPD patients, family-caregivers, and stakeholders. The program offers tailored services to address individual patients' needs and priorities at the hospital and for 3months post discharge. We tested the program in a single-blinded RCT with 240 COPD patients who were randomized to receive the program or 'usual care'. Program participants were offered the opportunity to invite a family caregiver, if available, to enroll with them into the study. The primary outcomes were the combined number of COPD-related hospitalizations and Emergency Department (ED) visits per participant at 6months post discharge, and the change in health-related quality of life over the 6months study period. Other measures include 'all cause' hospitalizations and ED visits; patient activation; self-efficacy; and, self-care behaviors.

DISCUSSION

Unlike 1month transitional care programs that focus on patients' post-acute care needs, the BREATHE program helps hospitalized COPD patients manage the post discharge period as well as prepare them for long term self-management of COPD. If proven effective, this program may offer a timely solution for hospitals in their attempts to reduce COPD rehospitalizations.

Selecting target populations for ROPS retrofit programs in Pennsylvania and Vermont

Agriculture has the highest injury and fatality rates when compared with other U.S. industries, and tractor overturns remain the leading cause of agricultural fatalities. Rollover protection structures (ROPS) are the only proven devices to protect a tractor operator in the event of an overturn. These devices are 99% effective when used with a seatbelt. Nearly 49% of tractors in the U.S. are not equipped with a ROPS. Interventions such as social marketing, community awareness campaigns, and financial incentives have been directed at encouraging farmers to install ROPS on their unprotected tractors. The purpose of this study was to conduct similar comparisons of ROPS protection and readiness to retrofit in different segments of the Vermont and Pennsylvania farm communities. A telephone survey was used to collect data on ROPS prevalence, farm demographic characteristics, and farmer's stage of change relative to installing ROPS on farm tractors. Our data provide new and unique information on the prevalence of ROPS-equipped tractors relative to commodity, farm size, and a variety of other demographic variables. Extrapolating from these data, the commodities studied account for roughly 162,072 tractors across the two states. Of these, 85,927 (53%) do not have ROPS. Of these unprotected tractors, 77,203 are in Pennsylvania and 8,724 are in Vermont. Our other two research questions dealt with the farmer's stage of change and possible ways to segment this population. The stage of change portion of our work demonstrates that most Pennsylvania and Vermont farmers are not contemplating ROPS retrofitting in the near future. Since no major differences were found in the stage of change, the number of unprotected tractors was examined for each of the commodity groups. In Pennsylvania, 29% of all unprotected tractors were found on cash crop farms. This trend was even more apparent on smaller farms than large farms. This led to the selection of smaller cash crop farms as the target audience for social marketing messages. In contrast, researchers in Vermont found a bimodal distribution of unprotected tractors. Of all the commodity groups surveyed in Vermont, vegetable and cash crop farmers were least likely to have even one protected tractor to use on the farm. Probably the most encouraging finding from this study is that over 85% of Pennsylvania farms and over 87% of Vermont farms surveyed had at least one tractor available that had ROPS protection. Of those farms, 25.5% of the Pennsylvania farms and 46% of the Vermont farms have ROPS on all of their tractors. Both of these findings were greater than the findings from a 2006 survey of New York State farms, which found that 75% of surveyed New York farms have ROPS on at least one tractor and 18% have ROPS on all tractors. Even with these encouraging data, the goal of 100% of tractors with ROPS is far from being met. There are still an estimated 90,000 unprotected tractors on Pennsylvania and Vermont farms, and these farm owners are currently unmotivated to install ROPS. However as demonstrated in New York State, it may be possible to use social marketing that combines persuasive messages and cost-sharing to persuade these farmers that ROPS are indeed important and accessible.

Hypertension management in patients with renal cell cancer treated with anti-angiogenic agents

Inhibitors of the vascular endothelial growth factor (vegf-is) signalling pathway have fundamentally changed the treatment of metastatic renal cell carcinoma (mrcc). Hypertension is one of the most common side effects of vegf-is and has been reported with almost every vegf-i used for treatment to date. The exact mechanism of vegf-i-induced hypertension appears complex and multifactorial, and it remains to be fully explained. No randomized clinical trials are available to guide the management of hypertension during vegf-i treatment in mrcc patients. The guiding principles suggested here summarize the consensus of opinions on the diagnosis and management of vegf-i-induced hypertension during treatment of mrcc obtained from an expert working group composed of 4 Canadian medical oncologists and 5 Canadian hypertension specialists. The Canadian Hypertension Education Program guidelines, available literature, and expert opinion were used to develop the guiding principles.

The anorectic effect of CNTF does not require action in leptin-responsive neurons

Leptin resistance is a feature of obesity that poses a significant therapeutic challenge. Any treatment that is effective to reduce body weight in obese patients must overcome or circumvent leptin resistance, which promotes the maintenance of excess body fat in obese individuals. Ciliary neurotrophic factor (CNTF) is unique in its ability to reduce food intake and body weight in obese, leptin-resistant humans and rodents. Although attempts to use CNTF as an obesity therapy failed due to the development of neutralizing antibodies to the drug, efforts to understand mechanisms for CNTF's anorectic effects provide an opportunity to develop new drugs for leptin-resistant individuals. CNTF and leptin share several structural, anatomic, and signaling properties, but it is not understood whether or how the two cytokines might interact to affect energy balance. Here, we conditionally deleted the CNTF receptor (CNTFR) subunit, CNTFRα, in cells expressing leptin receptors. We found that CNTFR signaling in leptin-responsive neurons is not required for endogenous maintenance of energy balance and is not required for the anorectic response to exogenous administration of a CNTF agonist. These results indicate that despite anatomical overlap for CNTF and leptin action, CNTF appears to act within a distinct neuronal population to elicit its potent anorectic effect.

The primordial follicle reserve is not renewed after chemical or γ-irradiation mediated depletion

Reports indicate that germ-line stem cells present in adult mice can rapidly generate new oocytes and contribute to the primordial follicle reserve following conditions of ovotoxic stress. We further investigated the hypothesis that adult mice have the capacity to generate new oocytes by monitoring primordial follicle numbers throughout postnatal life and following depletion of the primordial follicle reserve by exposure to doxorubicin (DXR), trichostatin A (TSA), or whole-body γ-irradiation. We show that primordial follicle number remains stable in adult C57BL/6 mice between the ages of 25 and 100 days. However, within 2 days of treatment with DXR or TSA, primordial follicle numbers had declined to 65 and 51% respectively (P<0.05-0.01 when compared to untreated controls), with no restoration of follicle numbers evident after 7 days for either treatment. Furthermore, ovaries from mice subjected to sterilizing doses of γ-irradiation (0.45 or 4.5 Gy) revealed complete ablation of all primordial follicles 5 days after treatment, with no indication of follicular renewal. We conclude that neo-folliculogenesis does not occur following chemical or γ-irradiation mediated depletion of the primordial follicle reserve.

Abstract LB-331: Protein expression signatures of epidermal growth factor receptor inhibition

We have applied standardized shotgun and multiple reaction monitoring (MRM) proteomic platforms to detect protein expression changes associated with epidermal growth factor receptor (EGFR) stimulation and inhibition in A431 carcinoma cells. These experiments compared proliferating, stimulated (30 nmol EGF, 4h) with cells co-treated with EGF and either cetuximab (10 μg/ml) or gefitinib (500 nmol). The analyses are done by shotgun proteomics with liquid chromatography-tandem mass spectrometry (LC-MS/MS), using isoelectric focusing of peptide mixtures, followed by reverse phase LC-MS/MS on a Thermo LTQ instrument. Protein inventories (≥2 peptides per protein at 5% peptide FDR) for each set were approximately 3800 proteins at &lt; 3% protein FDR. Differential protein expression was estimated by comparison of spectral count data with a generalized linear modeling (GLM) approach. EGF stimulation induced expression changes in 148 proteins. Effects of the inhibitors on this “stimulation signature” were then determined by GLM comparisons of spectral count data for cetuximab- and gefitinib-treated cell proteomes. These analyses identified 13 proteins whose EGF-induced expression was reversed by both drugs, 15 proteins reversed by cetuximab and 57 proteins reversed by gefitinib. Targeted MRM analysis verified differential expression of the 13 proteins reversed by both drugs, which comprise an “EGF inhibition signature”. These include the transcription factors c-Jun and JunD and the cell cycle inhibitor Cip1, which were upregulated by EGF and the protein CCDC50, which was decreased by EGF. MRM analyses also identified EGF-induced protein expression changes that were selectively reversed by either cetuximab or gefitinib. Serum deprivation, rather than EGF stimulation may account for a subset of the 106 protein changes that were not reversed by inhibitors in EGF treated cells. Our analyses also identified 87 and 149 proteins that were not affected by EGF, yet were significantly altered by cetuximab and gefitinib, respectively. Activation of the EGFR axis is typically measured via the phosphorylation status of EGFR tyrosine kinase substrates and downstream targets, but these measurements are difficult to achieve in tissues due to the low abundance of phosphorylated protein forms and the challenge of preserving phosphorylation status during sample preparation. Protein expression changes directed by EGFR activation may provide more robust measures of EGFR activation and inhibition. Ongoing studies will test the hypothesis that an EGF inhibition signature provides an early index of therapeutic responses to EGFR-targeted cancer therapies. (Supported by NIH Grant U54CA126479)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-331. doi:10.1158/1538-7445.AM2011-LB-331

The cell polarity regulator hScrib controls ERK activation through a KIM site-dependent interaction

The cell polarity regulator, human Scribble (hScrib), is a potential tumour suppressor whose loss is a frequent event in late-stage cancer development. Little is yet known about the mode of action of hScrib, although recent reports suggest its role in the regulation of cell signalling. In this study we show that hScrib is a direct regulator of extracellular signal-regulated kinase (ERK). In human keratinocytes, loss of hScrib results in elevated phospho-ERK levels and concomitant increased nuclear translocation of phospho-ERK. We also show that hScrib interacts with ERK through two well-conserved kinase interaction motif (KIM) docking sites, both of which are also required for ERK-induced phosphorylation of hScrib on two distinct residues. Although wild-type hScrib can downregulate activation of ERK and oncogenic Ras co-transforming activity, an hScrib mutant that lacks the carboxy terminal KIM docking site has no such effects. These results provide a clear mechanistic explanation of how hScrib can regulate ERK signalling and begin to explain how loss of hScrib during cancer development can contribute to disease progression.