Super resolution-based methodology for self-supervised segmentation of microscopy images

Data-driven Artificial Intelligence (AI)/Machine learning (ML) image analysis approaches have gained a lot of momentum in analyzing microscopy images in bioengineering, biotechnology, and medicine. The success of these approaches crucially relies on the availability of high-quality microscopy images, which is often a challenge due to the diverse experimental conditions and modes under which these images are obtained. In this study, we propose the use of recent ML-based image super-resolution (SR) techniques for improving the image quality of microscopy images, incorporating them into multiple ML-based image analysis tasks, and describing a comprehensive study, investigating the impact of SR techniques on the segmentation of microscopy images. The impacts of four Generative Adversarial Network (GAN)- and transformer-based SR techniques on microscopy image quality are measured using three well-established quality metrics. These SR techniques are incorporated into multiple deep network pipelines using supervised, contrastive, and non-contrastive self-supervised methods to semantically segment microscopy images from multiple datasets. Our results show that the image quality of microscopy images has a direct influence on the ML model performance and that both supervised and self-supervised network pipelines using SR images perform better by 2%-6% in comparison to baselines, not using SR. Based on our experiments, we also establish that the image quality improvement threshold range [20-64] for the complemented Perception-based Image Quality Evaluator(PIQE) metric can be used as a pre-condition by domain experts to incorporate SR techniques to significantly improve segmentation performance. A plug-and-play software platform developed to integrate SR techniques with various deep networks using supervised and self-supervised learning methods is also presented.

Convergence research and training in computational bioengineering: a case study on AI/ML driven biofilm-material interaction discovery

Initially, research disciplines operated independently, but the emergence of trans-disciplinary sciences led to convergence research, impacting graduate programs and research laboratories, especially in bioengineering and material engineering as presented here. Current graduate curriculum fails to efficiently prepare students for multidisciplinary and convergence research, thus creating a gap between the students and research laboratory expectations. We present a convergence training framework for graduate students, incorporating problem-based learning under the guidance of senior scientists and collaboration with postdoctoral researchers. This case study serves as a template for transdisciplinary convergent training projects - bridging the expertise gap and fostering successful convergence learning experiences in computational biointerface (material-biology interface). The 18-month Advanced Data Science Workshop, initiated in 2019, involves project-based learning, online training modules, and data collection. A pilot solution utilized Jupyter notebook on Google collaborator and culminated in a face-to-face workshop where project presentations and finalization occurred. The program started with 9 experts in the four diverse fields creating 14 curated projects in data science (Artificial Intelligence/Machine Learning), material science, biofilm engineering, and biointerface. These were integrated into convergence research through webinars by the experts. The experts chose 8 of the 14 projects to be part of an all-day in-person workshop, where over 20 learners formed eight teams that tackled complex problems at the interface of digital image processing, gene expression analysis, and material prediction. Each team was comprised of students and postdoctoral researchers or research scientists from diverse domains including computer science, materials science, and biofilm research. Some projects were selected for presentation at the international IEEE Bioinformatics conference in 2022, with three resulting Machine Learning (ML) models submitted as a journal paper. Students engaged in problem discussions, collaborated with experts from different disciplines, and received guidance in decomposing learning objectives. Based on learner feedback, this successful experience allows for consolidation and integration of convergence research via problem-based learning into the curriculum. Three bioengineering participants, who received training in data science and engineering, have received bioinformatics jobs in biotechnology industries.

Development of a porous layer-by-layer microsphere with branched aliphatic hydrocarbon porogens

Porous polymer microspheres are employed in biotherapeutics, tissue engineering, and regenerative medicine. Porosity dictates cargo carriage and release that are aligned with the polymer physicochemical properties. These include material tuning, biodegradation, and cargo encapsulation. How uniformity of pore size affects therapeutic delivery remains an area of active investigation. Herein, we characterize six branched aliphatic hydrocarbon-based porogen(s) produced to create pores in single and multilayered microspheres. The porogens are composed of biocompatible polycaprolactone, poly(lactic-co-glycolic acid), and polylactic acid polymers within porous multilayered microspheres. These serve as controlled effective drug and vaccine delivery platforms.

An AI-based approach for detecting cells and microbial byproducts in low volume scanning electron microscope images of biofilms

Microbially induced corrosion (MIC) of metal surfaces caused by biofilms has wide-ranging consequences. Analysis of biofilm images to understand the distribution of morphological components in images such as microbial cells, MIC byproducts, and metal surfaces non-occluded by cells can provide insights into assessing the performance of coatings and developing new strategies for corrosion prevention. We present an automated approach based on self-supervised deep learning methods to analyze Scanning Electron Microscope (SEM) images and detect cells and MIC byproducts. The proposed approach develops models that can successfully detect cells, MIC byproducts, and non-occluded surface areas in SEM images with a high degree of accuracy using a low volume of data while requiring minimal expert manual effort for annotating images. We develop deep learning network pipelines involving both contrastive (Barlow Twins) and non-contrastive (MoCoV2) self-learning methods and generate models to classify image patches containing three labels—cells, MIC byproducts, and non-occluded surface areas. Our experimental results based on a dataset containing seven grayscale SEM images show that both Barlow Twin and MoCoV2 models outperform the state-of-the-art supervised learning models achieving prediction accuracy increases of approximately 8 and 6%, respectively. The self-supervised pipelines achieved this superior performance by requiring experts to annotate only ~10% of the input data. We also conducted a qualitative assessment of the proposed approach using experts and validated the classification outputs generated by the self-supervised models. This is perhaps the first attempt toward the application of self-supervised learning to classify biofilm image components and our results show that self-supervised learning methods are highly effective for this task while minimizing the expert annotation effort.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

A new design of multimedia big data retrieval enabled by deep feature learning and Adaptive Semantic Similarity Function

Nowadays, multimedia big data have grown exponentially in diverse applications like social networks, transportation, health, and e-commerce, etc. Accessing preferred data in large-scale datasets needs efficient and sophisticated retrieval approaches. Multimedia big data consists of the most significant features with different types of data. Even though the multimedia supports various data formats with corresponding storage frameworks, similar semantic information is expressed by the multimedia. The overlap of semantic features is most efficient for theory and research related to semantic memory. Correspondingly, in recent years, deep multimodal hashing gets more attention owing to the efficient performance of huge-scale multimedia retrieval applications. On the other hand, the deep multimodal hashing has limited efforts for exploring the complex multilevel semantic structure. The main intention of this proposal is to develop enhanced deep multimedia big data retrieval with the Adaptive Semantic Similarity Function (A-SSF). The proposed model of this research covers several phases "(a) Data collection, (b) deep feature extraction, (c) semantic feature selection and (d) adaptive similarity function for retrieval. The two main processes of multimedia big data retrieval are training and testing. Once after collecting the dataset involved with video, text, images, and audio, the training phase starts. Here, the deep semantic feature extraction is performed by the Convolutional Neural Network (CNN), which is again subjected to the semantic feature selection process by the new hybrid algorithm termed Spider Monkey-Deer Hunting Optimization Algorithm (SM-DHOA). The final optimal semantic features are stored in the feature library. During testing, selected semantic features are added to the map-reduce framework in the Hadoop environment for handling the big data, thus ensuring the proper big data distribution. Here, the main contribution termed A-SSF is introduced to compute the correlation between the multimedia semantics of the testing data and training data, thus retrieving the data with minimum similarity. Extensive experiments on benchmark multimodal datasets demonstrate that the proposed method can outperform the state-of-the-art performance for all types of data.

The effect of the transition to Electronic Patient Records on adherence to venous thromboembolism prophylaxis guidelines in general surgical patients

INTRODUCTION AND OBJECTIVES

Surgical patients are at risk of hospital-acquired venous thromboembolisms (VTEs), and preventative measures such as thromboembolism deterrent stockings (TEDs) and low molecular weight heparin (LMWH) are proven to be beneficial. The National Quality Requirement in the NHS Standard Contract 2017/19 in England mandates that 95% of inpatients undergo VTE risk assessments. As hospitals transition to Electronic Patient Records (EPR), it is important to observe the impact on vital safety indicators such as VTE risk. The aim of this study is to observe the effect of implementing EPR in a tertiary centre on adherence to national guidelines, including VTE assessment rates and prophylaxis administration in surgical patients.

MATERIALS AND METHODS

Using consecutive sampling, all acute surgical admissions at the hospital from 26/02/2018 to 18/03/2018 (n=154) pre-EPR and 31/10/2018 to 25/11/2018 (n=151) post-EPR were observed for VTE risk assessment, 24-h re-assessment, prophylaxis prescriptions, administration, and patient compliance. Data was compared using a two-tailed Z-test.

RESULTS

Pre-EPR, 96% of patients had completed VTE assessments, which increased after EPR implementation to 97% (p=0.39). LWMH prescription rates decreased from 82% to 77% following EPR (p=0.14). Moreover, TED prescriptions decreased from 84% to 64% post-EPR (p<0.01). Administration rates of prophylaxis generally improved post-EPR. The 24-h re-assessment rate decreased from 62% to 54% of patients (p=0.08).

CONCLUSION

The study demonstrated that EPR is non-inferior to paper records. Transitioning to an EPR system did not interfere with the completion of VTE risk assessments, hence did not negatively impact the ability to achieve national targets.

Correction of perceived visual distortions using a software application and correlation to age-related macular degeneration

Purpose:

To investigate the use of software-generated corrections in neutralizing perceived distortions in age-related macular degeneration.

Methods:

A tablet-based application was utilized to elicit distortions. Five subjects (seven eyes: neovascular age-related macular degeneration and three eyes: non-neovascular age-related macular degeneration) traced the reference lines, and their distortion traces were recorded. To counter distortion, a software-generated trace was re-traced by subjects to produce a corrected trace. Final traces were superimposed on optical coherence tomography images and following distances calculated: (a) dDT: distance between distortion trace and reference line; (b) dGT: distance between software-generated trace and corrected trace; (c) dCT: distance between corrected trace and reference line. Mean percent improvement in distortion was reported. Mean effectiveness of correction was also reported by utilizing t test to compare dDT and dCT. The number of distortion traces with underlying lesions on optical coherence tomography was also analyzed.

Results:

Mean age of the subjects was 76.6 (±9.5) years. Each patient traced six reference lines and each was considered a separate case. Out of 30 cases, 17 (56.6%) elicited distortion. Mean percent improvement in distortion was 71.3 ± 23% (p < 0.05). Twelve cases (70.6%) had an underlying lesion (eight cases: disrupted photoreceptor layer and four cases: normal photoreceptor layer). Mean percent improvement in cases with normal photoreceptor layer (90.8 ± 5.45%) was higher than with abnormal photoreceptor layer (58.5 ± 7.17%) (p < 0.05). Five cases with distortion had no associated underlying lesion. Mean percent improvement in these subjects was significantly higher than those with photoreceptor layer disruption.

Conclusion:

Software-generated corrections can potentially correct for perceived distortions in patients with age-related macular degeneration, especially in cases with preserved photoreceptor layer.

Psychiatric morbidity and HIV in female drug dependants in Malaysia

Female drug dependants (n = 171) and controls (n = 1137) were studied to search for psychiatric morbidity in them. The psychiatric morbidity was found to be 36.3% and 6.9%, respectively. The most common psychiatric disorder found was dysthymic disorder followed by adjustment disorder, anxiety disorder and borderline personality disorder. The diagnosis was significantly dependent on the type of drug used (P < 0.001) and HIV seropositivtty status of the patients (P = 0.04). The findings highlight the relationship of the psychiatric morbidity to the HIV status and female drug users.

The Effect of Freezing Time on Muscle Fiber Mechanical Properties

The purpose of this study was to investigate the effect of freezing time on the functional behavior of mouse muscle fibers. Passive mechanical tests were performed on single soleus muscle fibers from fresh (0 month) and preserved (stored at -20°C for 3, 6, 9 and 12 months) 3 month old mice. The Young's modulus and the dynamic and the static stresses were measured. A viscoelastic Hill model of 3rd order was used to fit the experimental relaxation test data. The statistical analysis corresponding to the elastic modulus of single muscle fibers did not differ when comparing fresh and stored samples for 3 and 6 months at -20 °C. From 9 months, fibers were less resistant and the mechanical properties were damaged. The primary goal of this study was to complete the gold standard process of muscle fiber preservation for subsequent mechanical property studies. We have demonstrated that muscle fibers can be stored at -20°C for up to 6 months without altering their mechanical properties.

Solar insolation in springtime influences age of onset of bipolar I disorder

OBJECTIVE

To confirm prior findings that the larger the maximum monthly increase in solar insolation in springtime, the younger the age of onset of bipolar disorder.

METHOD

Data were collected from 5536 patients at 50 sites in 32 countries on six continents. Onset occurred at 456 locations in 57 countries. Variables included solar insolation, birth-cohort, family history, polarity of first episode and country physician density.

RESULTS

There was a significant, inverse association between the maximum monthly increase in solar insolation at the onset location, and the age of onset. This effect was reduced in those without a family history of mood disorders and with a first episode of mania rather than depression. The maximum monthly increase occurred in springtime. The youngest birth-cohort had the youngest age of onset. All prior relationships were confirmed using both the entire sample, and only the youngest birth-cohort (all estimated coefficients P < 0.001).

CONCLUSION

A large increase in springtime solar insolation may impact the onset of bipolar disorder, especially with a family history of mood disorders. Recent societal changes that affect light exposure (LED lighting, mobile devices backlit with LEDs) may influence adaptability to a springtime circadian challenge.

Help-seeking for sleep problems among psychiatric outpatients

Introduction

Though sleep disturbances are common among psychiatric patients, some patients may trivialize their problem and not discuss it with their doctors. This study thus aimed to assess patient profile that is associated with help seeking for sleep problems among psychiatric patients.

Methods

Outpatients from a tertiary psychiatric hospital were recruited for this study (n = 400). The pittsburgh sleep quality index was administered to identify cases of probable insomnia, and daytime impairment due to sleep disturbances was recorded. Participants were asked if they have ever consulted a doctor or any health professionals for their sleep problems. Sociodemographic information was recorded and clinical profile was obtained from the patient's medical records. Multivariate logistic regression was used to examine correlates of help-seeking behaviour among patients with probable insomnia.

Results

275 cases of probable insomnia were identified. Among this group of patients, 38.9% had never sought help for their sleep problems. Participants who were single were less likely to seek help as compared to those who were widowed/separated/divorced (OR= 0.319, P = 0.023). Having a comorbid psychiatric condition was independently associated with increased odds of help seeking (OR= 1.952, P = 0.027). Participants who perceived greater daytime impairment due to sleep problems were more likely to seek help (OR= 1.465, P = 0.007).

Conclusions

The majority of psychiatry patients with sleep problems sought professional help, though there remained a substantial group that did not do so. There is a need to educate and create awareness of potential sleep problems among psychiatric patients, and to inform them of the availability of treatment.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Abstract P1-08-03: Identification and characterization of a novel endoxifen substrate, PKCβ1, and its interaction with the estrogen receptor

Background: The primary mechanism by which tamoxifen (Tam) and its metabolites exert their biologic effects is through estrogen receptor (ER) binding and inhibition of ER signaling. We and others demonstrated that endoxifen (Endx) has greater antitumor activity in vitro and in vivo compared to Tam and the first-in-human Endx phase I study demonstrated its antitumor activity in patients with prior progression on Tam (Goetz SABC 2015). PKCs are a family of serine/threonine-specific protein kinases that regulate signaling pathways involved in cell proliferation and tumorigenic transformation. Our prior protein docking studies suggested endoxifen may be a substrate for PKCs. Here we report the effects of Tam and Endx on PKCβ1 binding, kinase activity, as well as interactions between PKCβ1 and ERα.

Methods: Surface Plasmon Resonance (SPR, Biacore T200, GE Healthcare) was used to evaluate binding of Tam, N-desmethyl Tam (NDMT), 4-HT, and Endx to PKCβ1 and PKCβ2. The effects of Tam and Endx on PKCβ1 kinase activity were determined. Proliferation and colony formation in MCF7 parental and PKCβ1 overexpressing cells were evaluated. siRNA silencing was used to knockdown PKCβ1 expression in the following cells: MCF7 aromatase expressing cells that were either sensitive (MCF7/AC1) or resistant to letrozole (MCF7/AC1 L-resistant); T47D; and MDA-MB-361. Coimmunoprecipitation assay and DUOlink in situ proximity ligation were used to investigate the interaction between PKCβ1 and ERα.

Results: Endx more potently inhibited PKCβ1 kinase activity compared to Tam ( IC50 350 nM vs 47.8 μM ) with KDs for PKCβ1 binding as follows: Endx (100 nM ), Tam ( 2 μM ), 4-HT ( 2 μM ) and NDMT (&gt; 7 μM ). None of the SERMs exhibited PKCβ2 binding. In the MCF7/AC1 and MCF7/AC1 L-resistant cells, PKCβ1 knockdown resulted in ERα degradation and potently inhibited cell proliferation. These results were confirmed in T47D and MDA-MB-361 cells. Notably, PKCβ1 knockdown in MCF7/AC1 cells resulted in significantly greater E2 induced proliferation comparing siRNA knockdown vs. control. To further explore these effects, we evaluated the effects of PKCβ1 overexpression in MCF7 cells and demonstrated that PKCβ1 overexpression reduced cell proliferation and colony formation compared to parental MCF-7 cells without affecting ERα protein stability. Coimmunoprecipitation assays in transient transfected MCF-7 cells with exogenous PKCβ1 as well as PKCβ1 expressing MDA-MB-231 cells transiently or stably transfected with ERα demonstrated PKCβ1 and ERα interaction, with confirmation by Duolink assay that this interaction occurs in the cytoplasm.

Conclusions: Our findings demonstrated that endoxifen binds and inhibits PKCβ1 at relevant concentrations achieved in the endoxifen clinical trial studies. PKCβ1 interacts with cytoplasmic ERα and PKCβ1 knockdown inhibits cell proliferation and enhances ERα turnover. However, in PKCβ1 overexpressing cells, PKCβ1 may exhibit tumor suppressive effects. These data suggest a complex interaction between PKCβ1 and ERα and that endoxifen's effects on PKCβ1 may alter drug response of endocrine therapy. Further studies are ongoing to characterize the role of PKCβ1 and its role in ER biology and response to endoxifen.

Citation Format: Guo C, Kuffel MJ, Kudgus RA, Huang Z, Bode AM, Cheng J, Suman VJ, Reid JM, Bruinsma ES, Subramaniam M, Ames MM, Hawse JR, Goetz MP. Identification and characterization of a novel endoxifen substrate, PKCβ1, and its interaction with the estrogen receptor [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-08-03.

Factors Influencing Attitudes Towards Seeking Professional Psychological Help: Findings From A Multi-Ethnic Asian Population-Based Study

Introduction

Various socio-demographic variables have been shown to influence attitudes towards seeking professional psychological help (ATSPPH), while negative ATSPPH can act as a barrier to mental healthcare, resulting in under-utilization of psychological services.

Aims and objectives

To explore the factor structure of the ATSPPH scale and determine whether any significant socio-demographic differences exist in relation to ATSPPH among a nationally representative sample.

Methods

Data was extracted from a population-based, cross-sectional survey conducted between March 2014 and March 2015 among Singapore Residents aged 18-65 years (n = 3006). Respondents completed the 10-item ATSPPH scale and also provided socio-demographic information. Exploratory factor analysis (EFA) was performed to establish the factor structure of the ATSPPH scale. Multivariable linear regression analyses were conducted to examine socio-demographic factors associated with ATSPPH.

Results

EFA revealed that the ATSPPH scale formed three distinct dimensions comprising “Openness to seeking professional help”, “Value in seeking professional help” and “Preference to cope on your own”. Higher “Openness to seeking professional help” scores were significantly associated with 18-34-year-olds and unmarried respondents, whilst Malay ethnicity and lower education were significantly associated with lower openness scores. Malays, Indians and lower education were significantly associated with lower “Value in seeking professional help” scores, whereas higher “Preference to cope on your own” scores were significantly associated with lower education.

Conclusion

Population subgroups including those with lower educational levels and different ethnic groups have more negative ATSPPH. Tailored, culturally appropriate educational interventions which reduce negative ATSPPH are needed, which effectively target these populations.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Abstract P5-04-01: ERβ elicits tumor suppressive effects in triple negative breast cancer through the induction of cystatins and suppression of TGFβ signaling

Background: Triple negative breast cancer (TNBC) accounts for approximately 20% of all breast cancer diagnoses. Clinical management of TNBC is limited to surgery, chemotherapy and radiation due to lack of estrogen receptor alpha and HER2 expression. Recently, we have shown that approximately 40% of TNBCs express estrogen receptor beta (ERβ) and have begun to explore the possibility that this receptor could be utilized as a novel therapeutic target for this disease.

Methods: To examine the biological functions of ERβ in TNBC, novel ERβ expressing TN cell lines (MDA-MB-231 and Hs578T) were developed. In vitro experiments were employed to determine alterations in the global gene expression profiles, biological pathways, proliferation rates, and cell cycle progression following estrogen or ERβ-specific agonist treatment. Cell line xenografts were also established in athymic ovariectomized nude mice to examine tumoral responses to ERβ targeting agents and to investigate gene and protein expression patterns as well as potential serum biomarkers indicative of therapeutic response. Additionally, using the resources of the Mayo Clinic Breast Cancer Genome Guided Therapy Study (BEAUTY), we have identified, and begun to analyze, ERβ+ and ERβ- patient derived xenografts (PDX) established from women with TNBC.

Results: Our studies have revealed that both estrogen and multiple ERβ-specific agonists elicit significant anti-proliferative effects in ERβ+ TNBC cells primarily through a G1/S phase cell cycle arrest. These anti-proliferative effects appear to be mediated by cystatins, a family of small secreted cysteine protease inhibitors which are highly induced following estrogen and ERβ-specific agonist treatment. Conditioned media isolated from estrogen or ERβ-specific agonist treated cells decreased the proliferation rates of multiple non-ERβ expressing cell lines; effects that were completely reversed when cystatins were depleted from the media. In addition, we have shown that activation of ERβ, and the subsequent induction of cystatin gene expression, leads to suppression of canonical TGFβ signaling through multiple mechanisms including suppression of TGFβR2 expression, induction of Smad7 expression and blockade of TGFβ ligand-mediated activation of this pathway both in vitro and in vivo. Finally, ERβ+ TNBC PDXs exhibit significantly decreased tumor growth rates in estrogen-treated mice compared to ERβ- TN breast tumors.

Conclusions: Our in vitro and in vivo data show that estrogen and ERβ-specific agonists elicit anti-cancer effects in ERβ+ TNBC. These effects appear to be mediated, in part, by cystatins through their inhibitory effects on canonical TGFB signaling, a pathway known to drive TNBC progression. Importantly, these data lay the foundation for studies aimed at examining the ability to therapeutically target ERβ in TNBC patients.

Citation Format: Reese J, Bruinsma E, Subramaniam M, Suman V, Pitel K, Kalari K, Yu J, Wang L, Goetz M, Ingle J, Hawse J. ERβ elicits tumor suppressive effects in triple negative breast cancer through the induction of cystatins and suppression of TGFβ signaling. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-04-01.

Association of Grip Strength, Upper Arm Circumference, and Waist Circumference with Dementia in Older Adults of the WiSE Study: A Cross-Sectional Analysis

OBJECTIVE

We examined the associations of handgrip strength, upper arm circumference, and waist circumference with dementia among Singapore older adults.

DESIGN

Cross-sectional epidemiological study.

SETTING

Residential homes, day care centres, nursing homes and institutions.

PARTICIPANTS

2,565 men and women aged 60 years and above who participated in the Well-being of the Singapore Elderly (WiSE) study in 2013.

MEASUREMENTS

Socio-demographic correlates, dietary habits, health behaviours, grip strength, upper arm circumference, and waist circumference were collected. Grip strength was measured using a hand dynamometer with the dominant hand. Upper arm circumference was measured using a measuring tape around the thickest part of the upper arm while waist circumference measured in centimetres was measured at the narrowest part of the body between the chest and hips for women, and measured at the level of the umbilicus for men. Dementia was diagnosed using the 10/66 dementia diagnostic criteria.

RESULTS

Mean grip strength was 13.07 kg (SE=0.60) for people with dementia and 21.98 kg (SE=0.26) for people without dementia. After adjusting for all factors, grip strength remained significantly associated with dementia (p <0.0001). Upper arm circumference was associated with dementia (p <0.0001) but this association was only significant in the univariate analysis. Waist circumference was not significantly associated with dementia.

CONCLUSIONS

Lower grip strength was independently associated with dementia in the older adult population in Singapore. Further research needs to be done to ascertain whether this association exists for specific types of dementia and look into the relationship of other anthropometric measurements with dementia in Singapore.

Analyzing OCT images of age-related macular degeneration patients to identify spatial health correlations

An approach to automatically group age-related macular degeneration (AMD) patients having similar retinal health profiles by clustering Optical Coherence Tomography (OCT) images is described. Spatial health patterns within and across profiles are discovered by identifying segments of images that have similar levels of health in a given retina region. Segmentations of various sizes are considered and the segmentation where the segment similarity most closely matches the discovered health profiles is used to identify health patterns. Our experiments with OCT images of 10 AMD patients show that - i) health profiles generated by clustering closely correspond to those identified by a physician expert, ii) a rich set of spatial patterns can be discovered within and across profiles using regular image segmentation, and iii) new images can be successfully classified into existing profiles so that physicians can provide effective profile-based treatments.

Latent structure of psychosis in the general population: results from the Singapore mental health study

BACKGROUND

Few studies have examined the latent construct of psychotic symptoms or distinguished between the latent construct and its manifest indicators. The current study aimed to investigate the latent structure of psychotic symptoms using factor mixture modeling (FMM) and to use the best-fitting model to examine its sociodemographic and clinical correlates.

METHOD

The Singapore Mental Health Study (SMHS) was based on an adult representative sample of the Singapore population. Psychotic symptoms were assessed by using the Psychosis Screen section of the Composite International Diagnostic Interview version 3.0 (CIDI 3.0). FMM analyses were applied to determine the latent construct of psychotic symptoms. Sociodemographic and clinical correlates of the latent structure of psychosis symptoms were examined using multiple linear and logistic regression analyses.

RESULTS

The overall weighted lifetime prevalence of any psychotic experience was 3.8% in the SMHS after excluding subthreshold experiences. The FMM analysis clearly supported the dimensional model of the latent structure of psychotic symptoms. On deriving the total score for 'psychosis symptoms' in accordance with the one latent trait model, and correlating it with sociodemographic factors, we found that female gender, vocational education, current and past smokers were positively associated with the 'psychosis' total score.

CONCLUSIONS

There is a need for an increased understanding of, and research into, this intermediate state of 'psychosis symptoms' that do not meet diagnostic criteria for psychosis. It is also important to learn more about the group of individuals in the community who may have preserved functioning to elucidate the protective factors that prevent transition to psychosis.

Abstract P6-04-03: ERb and breast cancer: A potential predictive and prognostic biomarker and novel therapeutic drug target

Background: Estrogen receptor beta (ERβ), unlike ERα, classically functions as a tumor suppressor in vitro. However, ERβ's biological functions in vivo and predictive/prognostic value in breast cancer are controversial.

Methods: Expression of ERβ protein was determined using a well characterized and validated ERβ specific monoclonal antibody that only recognizes the full-length form of this receptor (PPG5/10) in the following 3 cohorts: 1) a cohort with all breast cancer subtypes (n = 182), 2) a prospective NCCTG adjuvant tamoxifen trial for postmenopausal women with ERα positive breast cancer with long-term follow-up (n = 198) and 3) a cohort of 80 triple negative breast cancers (TNBCs). To elucidate the biological functions of ERβ in breast cancer, novel ERβ expressing MCF7 and MDA-MB-231 cell lines were developed and characterized using multiple techniques and were examined for responsiveness to various ERβ targeted therapies.

Results: About one-third of all breast tumors, regardless of sub-type, were shown to express nuclear ERβ and this expression was independent of ERα or HER2. In the NCCTG 89-30-52 cohort, breast cancer recurrence rates were significantly associated with ERβ protein expression with 10 year recurrence rates of 25%, 15% and 4% for zero, low or high levels of ERβ expression respectively. Interestingly, in TNBCs, nuclear ERβ was expressed at intermediate or high levels in 24% of tumors. In the triple negative MDA-MB-231 cell line, expression of ERβ led to inhibition of proliferation and induction of apoptosis in response to estrogen and multiple ERβ specific agonists. Conversely, these same treatments induced proliferation of ERβ-expressing MCF7 cells which endogenously express ERα. However, ERβ expression sensitized MCF7 cells to the anti-proliferative effects of anti-estrogens. Microarray analysis and RT-PCR profiling of MDA-MB-231-ERβ cells revealed that estrogen and ERβ agonists highly induced the expression of multiple cystatins, a family of small secreted cysteine protease inhibitors which function as tumor suppressors, and potently inhibited canonical TGFβ signaling. Conditioned media isolated from estrogen or ERβ agonist treated MDA-MB-231-ERβ cells suppressed the proliferation rates and inhibited TGFβ signaling in other TNBC cell lines, effects that were completely reversed following the depletion of cystatins from the conditioned media.

Conclusions: These data demonstrate that ERβ is expressed in a substantial proportion of breast cancers and may have value as a predictive and/or prognostic biomarker. Therapeutic targeting of ERβ may have clinical benefit in multiple breast cancer sub-types; however, the specific drug of choice may vary based on ERα status. Specifically, we have demonstrated that ERβ expression in ERα+ MCF7 cells sensitizes them to the effectiveness of anti-estrogens, an observation that was confirmed in women enrolled in a prospective adjuvant tamoxifen trial. In TNBCs, where targeted therapies are lacking, our data suggest that targeting ERβ with either estrogen or ERβ specific agonists will elicit anti-tumor effects through the induction of cystatins and inhibition of TGFβ signaling resulting in tumor regression and improved patient outcomes.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-04-03.

Abstract P5-05-01: Endoxifen, a novel breast cancer therapy, elicits unique beneficial effects on bone relative to that of other selective estrogen receptor modulators

Background: Commonly used endocrine therapies for breast cancer, such as aromatase inhibitors in postmenopausal women and tamoxifen in premenopausal women, have deleterious effects on bone mineral density. Therefore, the identification of novel cancer therapies which either maintain or improve bone mass are of clinical need. We and others have previously demonstrated that endoxifen is the most active tamoxifen metabolite responsible for eliciting the anti-cancer effects of this drug and that endoxifen concentrations are an important factor with regard to tamoxifen efficacy. These studies have led to the development of endoxifen as a novel anti-breast cancer drug for which phase I clinical trials are now underway. At present, there are no data regarding endoxifen's effects on bone.

Methods: The effects of endoxifen on osteoblast gene expression profiles were compared to that of estrogen, tamoxifen, raloxifene and lasofoxifene by microarray and RT-PCR analyses in both estrogen receptor alpha (ERα) and ERβ expressing cell lines. The in vivo effects of an anti-cancer dose of endoxifen (50mg/kg/day) on the skeleton were first analyzed in 3-month-old ovariectomized C57BL/6 mice using Dual-energy X-ray absorptiometry, peripheral Quantitative Computed Tomography, micro-Computed Tomography and histomorphometry. In a second set of studies, a pre-clinical rat model was used to determine the effects of endoxifen (10mg/kg/day) on the skeleton in both a pre- and post-menopausal setting.

Results: Endoxifen treatment of ERα and ERβ expressing mouse osteoblast cells led to dramatically different gene expression profiles when compared to that of estrogen and other anti-estrogens. In ovariectomized mice, daily administration of endoxifen led to significant increases in bone mineral density and content throughout the skeleton relative to vehicle control treated animals. The numbers and activity of both osteoblasts and osteoclasts were also found to be significantly higher in endoxifen treated mice. In the pre-clinical model system, endoxifen treatment of 4 month-old ovariectomized Sprague-Dawley rats significantly protected against bone loss following estrogen depletion primarily due to suppression of osteoclast mediated bone resorption. Importantly, in sham operated rats (thus retaining ovarian function), endoxifen treatment enhanced bone volume and trabecular thickness and did not suppress osteoclast activity.

Conclusions: These data are the first to examine the effects of the novel breast cancer therapy, endoxifen, on bone and reveal that the molecular mechanisms of action of this compound are substantially different than that of other SERMs. Endoxifen was shown to protect against bone loss following estrogen depletion in both mice and rats and interestingly, enhanced bone mass in ovary intact rats, an observation that is in stark contrast to the known effects of tamoxifen which induces bone loss in the “pre-menopausal” setting. These studies suggest that endoxifen may have superior bone-beneficial effects compared to tamoxifen, and if efficacy is confirmed in later phase trials, endoxifen may represent a better drug of choice for a sub-set of breast cancer patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-05-01.

Symptomatic and functional remission in patients with first-episode psychosis

OBJECTIVE

For patients suffering from psychotic disorders and their caregivers, 'recovery' remains important. Our study aims to examine the rates of both symptomatic and functional remission in first-episode psychosis (FEP) patients at 2 years and identify sociodemographic and clinical factors associated with recovery.

METHOD

In this naturalistic study, all consecutive FEP patients presenting to an early psychosis intervention programme were recruited. Symptomatic remission was defined by the Schizophrenia Working Group's criteria; functional remission was defined as a Global Assessment of Functioning (GAF) disability score of ≥61 with engagement in age-appropriate vocation. Simple and multiple logistic regressions using stepwise method were used.

RESULTS

Out of 1175 patients, 636 (54.1%) met criteria for symptomatic remission, 686 (58.4%) for functional remission, while 345 (29.4%) met for both. Multiple logistic regression revealed female gender (OR 1.47; 95%CI, 1.12-1.93), those married (OR 1.49; 95%CI, 1.02-2.18), younger age (OR 0.98; 95%CI, 0.95-0.99), tertiary education (OR 1.56; 95%CI, 1.02-2.38), shorter DUP (OR 0.99; 95%CI, 0.98-0.99), lower baseline PANSS negative scores (OR 0.97; 95%CI, 0.95-0.99), and early response at month 3 (OR 1.78; 95%CI, 1.31-2.42), as significant predictors of recovery at year 2.

CONCLUSION

Our results indicate that strategies to reduce DUP and achieve early response could improve remission rates in FEP patients.

P3-16-09: Endoxifen, a Newly Developed Breast Cancer Drug, Has Anabolic Actions on the Mouse Skeleton

Background

Commonly used endocrine therapies for breast cancer, such as aromatase inhibitors in postmenopausal women and tamoxifen in premenopausal women, have deleterious effects on bone mineral density. Therefore, the identification of novel cancer therapies which either maintain or improve bone mass are of clinical need. We have recently demonstrated that endoxifen is the most active tamoxifen metabolite with regard to inhibiting the growth of ERα+ breast cancer cells and these studies have led to the development of endoxifen as a novel anti-breast cancer drug for which first-in-human studies are now underway. At present, there are no data regarding endoxifen's effects on bone.

Methods: The effects of endoxifen on osteoblast (OB) and osteoclast (OC) maturation and gene expression were monitored by cell differentiation assays and real-time PCR. Dual-energy X-ray absorptiometry (DXA), peripheral Quantitative Computed Tomography (pQCT) and micro-Computed Tomography (μCT) were used to determine changes in bone density, mass and architecture following 45 days of oral endoxifen administration (50mg/kg/day) to 3-month-old ovariectomized (OVX) C57BL/6 mice relative to vehicle control treated animals. Alterations in the numbers and activity of OBs and OCs were determined by histomorphometry and serum levels of P1NP and CTX-1 respectively.

Results: Endoxifen treatment of mouse derived bone marrow stromal cells and human OBs led to significant increases in the expression of critical bone marker genes such as Runx2, osterix, osteocalcin, osteoprotegerin and alkaline phosphatase in a dose dependent manner. Daily administration of endoxifen to OVX mice led to significant increases in total body bone mineral density (BMD) (6%) and content (BMC) (9%), which was accompanied by a 50% decrease in fat tissue mass as determined by DXA. pQCT analysis of the tibial metaphysis revealed dramatic increases in BMD (35%) and BMC (20%), as well as trabecular density (52%), cortical content (62%), cortical area (60%) and cortical thickness (78%). μCT analysis of the femoral metaphysis revealed increases in bone volume/total volume (200%), trabecular number (38%) and trabecular thickness (18%), as well as decreased trabecular spacing (29%). Interestingly, there was nearly a 50% increase in the numbers of OCs derived from endoxifen treated mice which was associated with elevated expression of OC marker genes such as NFATcl, RANK, c-fms and cathepsin-K compared to control treated animals. Approximately 4 times as many OBs and OCs were observed on the bone surfaces of endoxifen treated mice which correlated with nearly 2-fold increases in serum levels of the bone formation (P1NP) and resorption (CTX-1) markers.

Conclusions: These data are the first to demonstrate that endoxifen has anabolic effects on the mouse skeleton which are similar to that of estrogen. Additionally, these data reveal that endoxifen's mechanism of action in bone is different than that reported for tamoxifen and other selective estrogen receptor modulators in mice as it increases, rather than decreases, bone formation and remodeling. Therefore, the use of endoxifen for the treatment of endocrine responsive breast cancer may avoid the detrimental skeletal effects of many conventional endocrine therapies.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-16-09.

P4-02-03: Biological Functions of Estrogen Receptor-beta and Its Variants in Breast Cancer

Background

The role of estrogen receptor alpha (ERα) in breast cancer has been studied extensively; yet, much less is known about full-length ERβ (ERβ1) and even less about its 4 variant forms (ERβ2-5). We have recently implicated a role for ERβ1 in sensitizing ERα expressing breast cancer cells to anti-estrogens. However, the ability of ERβ2-5 to modulate ERα and ERβ1 activity, and their association with cancer development, progression, and response to estradiol (E2) and anti-estrogens are not well understood. Here, we provide evidence that the presence of ERβ variants may be of diagnostic and clinical relevance for breast cancer patients and describe the development and characterization of a novel, highly specific monoclonal antibody (MC10) that is able to detect their expression in tumor biopsies.

Methods: Transient transfection and luciferase assays were used to determine the transcriptional activity of ERβ2-5 in response to E2 and anti-estrogens alone or in combination with ERα and ERβ1. A novel monoclonal antibody targeting all ERβ variants (MC10) was developed and characterized. The sub-cellular localization of ERβ2-5 was determined via confocal microscopy. Finally, the MC10 antibody was used to assess ERβ positivity in breast tumors and was compared to that of another monoclonal antibody which only detects ERβ1.

Results: Unlike ERβ1, ERβ2-5 do not activate an estrogen response element (ERE) in response to E2 and instead, slightly repress the activity of this reporter construct. Expression of ERβ2-5 does not significantly alter the transcriptional activity of ERβ1 following E2 treatment. However, ERβ2, 3 and 5, but not ERβ4, significantly enhance the E2-induced transcriptional activity of ERα. Interestingly, expression of ERβ3, 4 and 5, but not ERβ2, enhance the ability of anti-estrogens to block ERα mediated transcriptional activity. Confocal microscopy revealed that ERβ1 and 2 are almost exclusively localized to the cell nucleus. However, ERβ3-5 exhibit significant cytoplasmic and peri-nuclear localization. Immunohistochemistry of breast cancer biopsies using the MC10 antibody revealed multiple staining patterns including tumors which exhibit primarily nuclear staining and others primarily cytoplasmic, both in the presence and absence of ERα. These results are in contrast to the almost exclusive nuclear staining obtained on the same tumors with an ERβ1-specific antibody.

Conclusions: ERβ variants exhibit variable sub-cellular localization patterns and can influence the function of ERα, both in response to E2 and anti-estrogens. Therefore, the differential expression of ERβ variants and their cellular localization may influence breast cancer progression and/or therapeutic responses. The use of ERβ antibodies which do not detect all ERβ variants, or the use of a single ERβ antibody which does not discriminate between ERβ1 and its variants, is unlikely to reveal the complete biological significance of total ERβ expression in breast cancer and may in part explain the conflicting studies which have been reported for ERβ in the field.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-02-03.

Abstract P2-09-25: ERα Expression in Breast Cancer: A Conundrum of Antibody Specificity?

Background: The role of estrogen receptor alpha (ERα) in breast cancer has been studied extensively, and its protein expression is prognostic and a primary determinant of endocrine sensitivity; however, much less is known about the role of ERß. In vitro studies demonstrate a tumor suppressive function for ERß, and we have recently implicated a role for ERα in sensitizing ERα expressing breast cancer cells to the anti-estrogenic effects of endoxifen. However, the in vivo relevance of ERα remains unclear due to conflicting reports. Here, we provide evidence that some of this controversy may be explained by variability in antibody specificity. In addition, we describe the development and characterization of a novel, highly specific monoclonal antibody and provide data regarding ERα expression in human breast cancers.

Methods: Five commercially available ERα antibodies were screened for their sensitivity and specificity using western blotting, immunoprecipitation, immunofluorescence and immunohistochemistry in known ERα negative and positive cell lines as well as in normal human tissue samples. A novel monoclonal ERα antibody (C10) was developed and characterized in the same manner. Following identification of two specific antibodies, ERα expression was assessed in 66 breast tumors collected prior to adjuvant therapy. Samples were scored separately for nuclear and cytoplasmic staining.

Results: In depth analysis of commercially available ERα antibodies reveled that the majority were non-specific with substantial cross-reactivity to ERα . Only one commercial antibody (PPG5/10), which solely recognizes full-length ERß, and our newly developed monoclonal antibody, which recognizes full-length and all 4 ERα variants, were determined to be sensitive and specific for ERα expression. These same two antibodies resulted in strong staining for endogenous levels of ERα protein in normal prostate tissue by immunohistochemistry. We further assessed these two antibodies in a set of breast tumors. Preliminary analysis revealed significant differences for ERα positivity between these two antibodies. Based on nuclear staining, 92% of tumors were ERα positive using the PPG5/10 antibody while only 34% were positive with C10. Approximately 50% of all tumors exhibited cytoplasmic staining with both antibodies. Conclusions: Our studies demonstrate that the majority of commercially available ERα antibodies are either non-specific or insensitive for the detection of ERα via immunohistochemistry. The present data call into question the relevance of prior studies which tested the association between clinical outcome and ERα expression and demonstrate the need to further analyze the role of ERα in breast cancer using highly specific and validated antibodies. While both the PPG5/10 and C10 antibodies are highly specific for ERß, the significant discrepancy in nuclear staining between them in breast tumors may be due to changes in epitope availability as a result of post-translational processing. Our newly developed C10 antibody could provide additional discriminatory features which may be useful in predicting response to therapy and/or associations with other clinicopathological factors and such studies are currently underway.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-25.

TGFbeta inducible early gene-1 directly binds to, and represses, the OPG promoter in osteoblasts

TGFbeta inducible early gene-1 (TIEG) is a member of the Krüppel-like family of transcription factors (KLF10) that plays an important role in TGFbeta mediated Smad signaling. In order to better understand the role of TIEG in bone, we generated TIEG knockout (KO) mice. Calvarial osteoblasts (OBs) isolated from these mice exhibit a reduced ability to support osteoclastogenesis in vitro. Gene expression studies revealed decreased receptor activator of NF-kappaB ligand (RANKL) and increased osteoprotegerin (OPG) expression in TIEG KO OBs, suggesting a potential role for TIEG in regulating the expression of these genes. Since OPG and RANKL are two important regulators of osteoclast (OC) differentiation, we sought to determine if TIEG directly regulates their expression. Luciferase constructs, containing fragments of either the mouse OPG promoter (-1486 to +133 bp) or the RANKL promoter (-2000 to +1 bp) were each cloned into the pGL3 basic reporter vector and transiently transfected into TIEG KO calvarial OBs with and without a TIEG expression vector. No significant changes in the activity of the RANKL promoter were detected in the presence of TIEG. However, OPG promoter activity was inhibited in the presence of TIEG protein suggesting that TIEG directly represses the expression of OPG in OBs. In order to determine the region of this promoter through which TIEG acts, sequential 5'-deletion constructs were generated. Transient transfection of these constructs revealed that the TIEG regulatory element(s) reside within a 200 bp region of the OPG promoter. Transient ChIP analyses, using a TIEG-specific antibody, revealed that TIEG binds to this region of the OPG promoter. Since we have previously shown that TIEG regulates target gene expression through Sp-1 sites, we examined this region of the OPG promoter for potential TIEG binding elements and identified four potential Sp-1 binding sites. Site-directed mutagenesis was used to determine if TIEG utilizes these Sp-1 elements to regulate the activity of the OPG promoter. The data demonstrate that two Sp-1 sites are likely to be involved in TIEG's repression of the OPG promoter. Taken together, these results confirm that TIEG directly binds to and inhibits OPG promoter activity in OBs, partially explaining the inability of TIEG KO OBs to fully support osteoclast differentiation.

Endoxifen, but not 4-hydroxytamoxifen, degrades the estrogen receptor in breast cancer cells: a differential mechanism of action potentially explaining CYP2D6 effect

Abstract #19

Background: Tamoxifen (TAM) is a standard endocrine therapy for the treatment of women with estrogen receptor (ER) positive breast cancer. TAM is activated by the cytochrome P450 2D6 enzyme system into two potent and active metabolites, 4-hydroxytamoxifen (4HT) and 4-hydroxy-N-desmethyl-tamoxifen (endoxifen). While human concentrations of 4HT are negligible and vary little in plasma (5-10 nM), endoxifen concentrations vary widely (10-180 nm), and women with genetically impaired CYP2D6 metabolism have significantly reduced endoxifen levels and a higher risk of breast cancer recurrence. Despite these observations, endoxifen's contribution to tamoxifen's overall drug effectiveness is uncertain.&#x2028; Methods: Using cells endogenously expressing ERa (MCF7, T47D) and cells stably transfected with ERa (Hs578T and U2OS), we examined the relative effects of TAM and its primary metabolites on ERa protein levels by western blotting, ERa transcriptional activity by luciferase reporter assays and real-time RT-PCR, and on ER positive breast cancer cell growth through the use of proliferation assays.&#x2028; Results: We have discovered that endoxifen induces ERa protein turnover through proteasomal degradation similar to that of ICI in a concentration and time-dependent manner. These findings are in stark contrast to TAM, N-desmethyl-tamoxifen (NDT) and 4HT, which stabilize the ER. Optimal degradation occurs only at endoxifen concentrations observed in human CYP2D6 extensive metabolizers (&gt; 40 nM) and persists even in the presence of TAM (300 nM), 4HT (7 nM), and NDT (700 nM) at concentrations observed in patients receiving tamoxifen therapy. In contrast, reducing endoxifen concentrations to those observed in a CYP2D6 poor metabolizer (20 nM), without altering TAM, 4HT, and NDT, results in ER stabilization. High endoxifen concentrations (100-1000 nM) completely block estrogen (E2)-induced ER transcriptional activity even in the presence of TAM, 4HT, and NDT, while low endoxifen concentrations (20-40 nM) do not. Further, low concentrations of endoxifen (20 nM) do not significantly alter E2-induced cell proliferation; however, high concentrations of endoxifen (100-1000 nM) completely block this process. Discussion: Our data demonstrate that endoxifen is a potent anti-estrogen that targets ERa for proteasomal degradation, blocks ERa transcriptional activity and inhibits E2-induced breast cancer cell proliferation. Importantly, these effects of endoxifen are observed at concentrations found in CYP2D6 extensive metabolizers and are maintained even in the presence of TAM, 4HT and NDT. These studies suggest that endoxifen may be the primary metabolite responsible for tamoxifen's effectiveness in the treatment of ER positive breast cancer and provide the impetus to evaluate whether TAM-related side-effects, such as thrombo-embolism and endometrial hyperplasia/carcinoma, are inversely associated with a patient's ability to metabolically activate tamoxifen.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 19.

TIEG-null mice display an osteopenic gender-specific phenotype

TGFbeta inducible early gene-1 (TIEG) was originally cloned from human osteoblasts (OB) and has been shown to play an important role in TGFbeta/Smad signaling, regulation of gene expression and OB growth and differentiation. To better understand the biological role of TIEG in the skeleton, we have generated congenic TIEG-null (TIEG(-/-)) mice in a pure C57BL/6 background. Through the use of DXA and pQCT analysis, we have demonstrated that the femurs and tibias of two-month-old female TIEG(-/-) mice display significant decreases in total bone mineral content, density, and area relative to wild-type (WT) littermates. However, no differences were observed for any of these bone parameters in male mice. Further characterization of the bone phenotype of female TIEG(-/-) mice involved mechanical 3-point bending tests, micro-CT, and histomorphometric analyses of bone. The 3-point bending tests revealed that the femurs of female TIEG(-/-) mice have reduced strength with increased flexibility compared to WT littermates. Micro-CT analysis of femurs of two-month-old female TIEG(-/-) mice revealed significant decreases in cortical bone parameters compared to WT littermates. Histomorphometric evaluation of the distal femur revealed that female TIEG(-/-) mice also display a 31% decrease in cancellous bone area, which is primarily due to a decrease in trabecular number. At the cellular level, female TIEG(-/-) mice exhibit a 42% reduction in bone formation rate which is almost entirely due to a reduction in double labeled perimeter. Differences in mineral apposition rate were not detected between WT and TIEG(-/-) mice. Taken together, these findings suggest that female TIEG(-/-) mice are osteopenic mainly due to a decrease in the total number of functional/mature OBs.

Estrogen-TGFbeta cross-talk in bone and other cell types: role of TIEG, Runx2, and other transcription factors

It is well established that E(2) and TGFbeta have major biological effects in multiple tissues, including bone. The signaling pathways through which these two factors elicit their effects are well documented. However, the interaction between these two pathways and the potential consequences of cross-talk between E(2) and TGFbeta continue to be elucidated. In this prospectus, we present known and potential roles of TIEG, Runx2, and other transcription factors as important mediators of signaling between these two pathways.

Seroprevalence of hepatitis C in intravenous opioid users presenting in the early phase of injecting drug use in Singapore

INTRODUCTION

All over the world, Hepatitis C virus (HCV) accounts for an estimated 130 million chronic infections. Injection drug use has become one of the most important risk factors for HCV, and within the injection drug user population, the prevalence of HCV antibody ranges from 70 to 95 percent depending on an individual's length of use and the prevalence of infection in the community. This study was undertaken to determine the prevalence of and the risk factors for Hepatitis C antibodies in injecting drug users presenting to the Community Addictions Management Programme (CAMP) in Singapore.

METHODS

Eligibility criteria for inclusion in this study were all intravenous buprenorphine users presenting to CAMP. 106 subjects, who consented to the study, completed an interviewer-administered questionnaire, and underwent a urine and blood analysis.

RESULTS

The prevalence rate for HCV was 42.5 percent among the subjects included in our study. The odds of seroprevalence in those sharing needles were 5.6 times that of those who were not, and the odds of seroprevalence among those using with others (peers or partners) were 6.3 times, as compared to among those who were individual users. Racial differences were also seen, but these could be accounted for by the sharing of needles.

CONCLUSION

This study provides important local data at the onset of an early buprenorphine-injecting epidemic in Singapore. This data is useful for disease prevention and healthcare planning.

Psychiatric morbidity in patients referred to an insomnia clinic

INTRODUCTION

Insomnia is a common complaint associated with psychiatric disorders. Detection and diagnosis of insomnia can be a challenge at the primary care level. Patients often present with various kinds of psychological symptoms. Therefore, a high index of suspicion and careful assessments are crucial in eliciting signs and symptoms and making an accurate diagnosis of primary insomnia or a psychiatric disorder.

METHODS

This study was undertaken at the end of 2005, and is a retrospective review of all patients referred to the Insomnia Clinic and seen by the principal author in a three-year period between 2002 and 2005. Relevant data was collected from the medical records of patients who attended the clinic during this period.

RESULTS

In this study of 141 patients seen at an Insomnia Clinic, 47.5 percent had primary insomnia, while 52.5 percent had a primary diagnosis of a psychiatric disorder. 41.1 percent of those diagnosed with a primary psychiatric disorder had comorbid psychiatric disorders and 4.3 percent had substance abuse problems.

CONCLUSION

The various psychiatric disorders present in this group of patients highlight the need for careful assessment and recognition of these associations.

Effect of TGF-beta inducible early gene deficiency on flexor tendon healing

The role of transforming growth factor beta (TGF-beta) in tendon healing is still not clearly established. TGF-beta affects gene expression primarily through the activation of the Smad signaling pathway. The first step in the Smad pathway is the expression of TGF-beta inducible early gene (TIEG). Recently, a TIEG knockout mouse has been developed. The purpose of this study was to examine the healing potential of flexor tendons in mice lacking the TIEG gene, and to further examine what role the TIEG pathway plays in flexor tendon repair. Twenty-two mice, consisting of 11 normal wild-type mice and 11 TIEG knockout mice, were euthanized at 8 to 12 weeks of age. The second through fifth FDL tendons of both hind feet were transected and repaired in zone 2. The repaired tendons were removed from the mice and placed into tissue culture. Tendons were then examined at days 3, 7, 14, 21, and 42 after surgery. Hematoxylin and eosin (HE) staining and immunohistochemical staining for TGF-beta, collagen type I, and collagen type III were performed. Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to examine expression of TGF-beta1, beta2, beta3, and collagen type I and III. At 42 days after surgery, HE staining showed coaptation of lacerated tendon ends in both groups. Both groups showed healing of the lacerated tendon, but the chronologic expression pattern of TGF-beta was different between the knockout and normal tendons. TIEG deficient tendons had delayed expression of TGF-beta when compared with control tendons. The collagen mRNA expression pattern was similar with both groups, but the expression level was different, with TIEG knockout tendons having a lower expression of collagen type I mRNA (p < 0.001). TGF-beta is thought to play a major role in tendon healing. Healing of tendons in the TIEG knockout mouse suggests the possibility of tendon healing in the absence of the Smad pathway. The knockout mouse model described in the present study provides a novel means for further understanding of the tendon healing process through isolated deletion of specific growth factors.