Effects of porcine somatotropin administration on the responses to dietary lysine and a near-ideal blend of amino acids on the amino acid composition of whole-body protein and amino acid accretion rate in growing pigs

An experiment was conducted to assess the effects of porcine somatotropin (pST) on the responses to a near-ideal blend of AA on the AA composition of empty, whole empty body (WEB) protein and WEB essential AA accretion rate in pigs from 22 to 60 kg BW. Forty Hampshire × Yorkshire gilts were individually penned and assigned to a 4 × 2 factorial arrangement of treatments consisting of 4 diets with and without pST injection. A fortified corn-soybean meal basal diet was formulated to contain 1.50% total Lys with Thr, Met, and Trp added to obtain a near-ideal blend of these AA relative to Lys. In 3 additional diets, Lys was reduced to 1.25, 1.00, and 0.75% by diluting the basal diet with cornstarch, cellulose, and sand such that the diets also contained the same ratios of AA. Pigs that received pST were administered a daily i.m. injection of 2 mg of pST. At 60 kg BW, the WEB (carcass, head, viscera, blood, nails, and hair) was ground and analyzed for proximate and AA composition. Administration of pST increased (P < 0.001) accretion rates of WEB protein and essential AA. Increasing dietary essential AA increased (quadratic, P < 0.03) accretion rate of WEB protein, His, Leu, Trp, and Val in pST-treated pigs, but not in untreated pigs. Lysine composition in the accreted WEB protein was not affected (P > 0.05) by dietary Lys. The efficiency of Lys utilization for WEB Lys accretion was linearly affected (P < 0.01) by dietary Lys. These results indicated that the dietary Lys needed to achieve maximum WEB Lys accretion is markedly increased by pST administration.

Improved adherence to hip fracture standards reduces mortality after hip fractures

BACKGROUND

Hip fractures are increasing in incidence due to increasing life expectancy. Mortality continues to improve but it is important to explore which factors are responsible for driving improvements.

METHODS

A cohort of hip fracture patients predating SARS-CoV-2 was examined to determine the predictors of adherence to the six Irish Hip Fracture Standards (IHFS) and the impact of adherence on short (30 day) and long term (1 year) mortality. Our primary aim was assess the impact of a single HFS and cumulative number of HFS on mortality after hip fracture. Our secondary aim was to determine the impact of the HFS which are intrinsically linked to specialist Geriatric care.

RESULTS

Across 962 patients, over 5 years, the factors which were associated with adherence to HFS were female gender, increasing ASA grade and being nursed on an orthopaedic ward. Patients with increasing ASA were more likely to have met HFS 4-6 (Geriatrician review HFS4, bone health HFS5 & specialist falls assessment HFS6), less likely to have surgery within 48 h are more likely to develop a pressure ulcer. If the patient was not nursed on an orthopaedic ward all HFS were less likely to be met. At 30 days HFS 4-6 were associated with a statistically significant odds ratio (OR) of being alive, while at one year HFS 1 (admitted to an orthopaedic ward within 4 h), 5 and 6 were associated with a statistically significant OR of being alive. As increasing numbers of hip fracture standards were met patients were more likely to be alive at 30 days and one year.

CONCLUSION

This study has identified that improved adherence to hip fracture standards are associated with improved mortality at 30 days and one year.

Alcohol Prevention in Urgent and Emergency Care (APUEC): Development and Evaluation of Workforce Digital Training on Screening, Brief Intervention, and Referral for Treatment

Excessive alcohol consumption carries a significant health, social and economic burden. Screening, brief intervention and referral to treatment (SBIRT) is one approach to identifying patients with excessive alcohol consumption and providing interventions to help them reduce their drinking. However, healthcare workers in urgent and emergency care settings do not routinely integrate SBIRT into clinical practice and raise a lack of training as a barrier to SBIRT delivery. Therefore, "Alcohol Prevention in Urgent and Emergency Care" (APUEC) training was developed, delivered, and evaluated. APUEC is a brief, stand-alone, multimedia, interactive digital training package for healthcare workers. The aim of APUEC is to increase positive attitudes, knowledge, confidence and skills related to SBIRT through the provision of (a) education on the impact of alcohol and the role of urgent and emergency care in alcohol prevention, and (b) practical guidance on patient assessment, delivery of brief advice and making referral decisions. Development involved collaborative-participatory design approaches and a rigorous six-step ASPIRE methodology (involving n = 28 contributors). APUEC was delivered to healthcare workers who completed an online survey (n = 18) and then participated in individual qualitative interviews (n = 15). Analysis of data was aligned with Levels 1-3 of the Kirkpatrick Model of Training Evaluation. Survey data showed that all participants (100%) found the training useful and would recommend it to others. Insights from the qualitative data showed that APUEC digital training increases healthcare workers' perceived knowledge, confidence and skills related to alcohol prevention in urgent and emergency care settings. Participants viewed APUEC to be engaging and relevant to urgent and emergency care workers. This digital training was perceived to be useful for workforce skills development and supporting the implementation of SBIRT in clinical practice. While the impact of APUEC on clinician behaviour and patient outcomes is yet to be tested, APUEC digital training could easily be embedded within education and continuing professional development programmes for healthcare workers and healthcare trainees of any discipline. Ultimately, this may facilitate the integration of SBIRT into routine care and contribute to population health improvement.

Attitudes and current practice in alcohol screening, brief intervention, and referral for treatment among staff working in urgent and emergency settings: An open, cross-sectional international survey

BACKGROUND

The aim of the study was to ascertain the views and experiences of those working in urgent and emergency care (UEC) settings towards screening, brief intervention, and referral to treatment (SBIRT) for alcohol, to inform future practice.

OBJECTIVES

To explore i) views towards health promotion, ii) views towards and practice of SBIRT, iii) facilitators and barriers to delivering SBIRT, iv) training needs to support future SBIRT practice, and v) comparisons in views and attitudes between demographic characteristics, geographical regions, setting and occupational groups.

METHODS

This was an open cross-sectional international survey, using an online self-administered questionnaire with closed and open-ended responses. Participants were ≥18 years of age, from any occupational group, working in urgent and emergency care (UEC) settings in any country or region.

RESULTS

There were 362 respondents (aged 21-65 years, 87.8% shift workers) from 7 occupational groups including physicians (48.6%), nurses (22.4%) and advanced clinical practitioners (18.5%). Most believed that health promotion is part of their role, and that SBIRT for alcohol prevention is needed and appropriate in UEC settings. SBIRT was seen to be acceptable to patients. 66% currently provide brief alcohol advice, but fewer screen for alcohol problems or make alcohol-related referrals. The most common barriers were high workload and lack of funding for prevention, lack of knowledge and training on SBIRT, lack of access to high-quality resources, lack of timely referral pathways, and concerns about patient resistance to advice. Some views and attitudes varied according to demographic characteristics, occupation, setting or region.

CONCLUSIONS

UEC workers are willing to engage in SBIRT for alcohol prevention but there are challenges to implementation in UEC environments and concerns about workload impacts on already-burdened staff, particularly in the context of global workforce shortages. UEC workers advocate for clear guidelines and policies, increased staff capacity and/or dedicated health promotion teams onsite, SBIRT education/training/resources, appropriate physical spaces for SBIRT conversations and improved alcohol referral pathways to better funded services. Implementation of SBIRT could contribute to improving population health and reducing service demand, but it requires significant and sustained commitment of time and resources for prevention across healthcare organisations.

RAGE inhibitor TTP488 (Azeliragon) suppresses metastasis in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive and metastatic cancer subtype, which is generally untreatable once it metastasizes. We hypothesized that interfering with the Receptor for Advanced Glycation End-products (RAGE) signaling with the small molecule RAGE inhibitors (TTP488/Azeliragon and FPS-ZM1) would impair TNBC metastasis and impair fundamental mechanisms underlying tumor progression and metastasis. Both TTP488 and FPS-ZM1 impaired spontaneous and experimental metastasis of TNBC models, with TTP488 reducing metastasis to a greater degree than FPS-ZM1. Transcriptomic analysis of primary xenograft tumor and metastatic tissue revealed high concordance in gene and protein changes with both drugs, with TTP488 showing greater potency against metastatic driver pathways. Phenotypic validation of transcriptomic analysis by functional cell assays revealed that RAGE inhibition impaired TNBC cell adhesion to multiple extracellular matrix proteins (including collagens, laminins, and fibronectin), migration, and invasion. Neither RAGE inhibitor impaired cellular viability, proliferation, or cell cycle in vitro. Proteomic analysis of serum from tumor-bearing mice revealed RAGE inhibition affected metastatic driver mechanisms, including multiple cytokines and growth factors. Further mechanistic studies by phospho-proteomic analysis of tumors revealed RAGE inhibition led to decreased signaling through critical BC metastatic driver mechanisms, including Pyk2, STAT3, and Akt. These results show that TTP488 impairs metastasis of TNBC and further clarifies the signaling and cellular mechanisms through which RAGE mediates metastasis. Importantly, as TTP488 displays a favorable safety profile in human studies, our study provides the rationale for evaluating TTP488 in clinical trials to treat or prevent metastatic TNBC.

Projecting the impact of an ebola virus outbreak on endangered mountain gorillas

Ebola virus is highly lethal for great apes. Estimated mortality rates up to 98% have reduced the global gorilla population by approximately one-third. As mountain gorillas (Gorilla beringei beringei) are endangered, with just over 1000 individuals remaining in the world, an outbreak could decimate the population. Simulation modeling was used to evaluate the potential impact of an Ebola virus outbreak on the mountain gorilla population of the Virunga Massif. Findings indicate that estimated contact rates among gorilla groups are high enough to allow rapid spread of Ebola, with less than 20% of the population projected to survive at 100 days post-infection of just one gorilla. Despite increasing survival with vaccination, no modeled vaccination strategy prevented widespread infection. However, the model projected that survival rates greater than 50% could be achieved by vaccinating at least half the habituated gorillas within 3 weeks of the first infectious individual.

Abstract P4-08-10: Azeliragon (TTP488), an orally- available small molecule RAGE inhibitor, reduces metastasis in preclinical mouse models of breast cancer

Background: Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype with a high metastatic rate. Despite significant advances in breast cancer therapeutics, due to the lack of specific therapeutic targets in TNBC, cytotoxic chemotherapy is still the mainstay of treatment for this BC subtype. Preclinical studies have shown that the Receptor for Advanced Glycation End-products (RAGE) drives the progression and metastasis of aggressive cancer subtypes, including TNBC. RAGE plays a multifaceted role in driving tumorigenesis and metastasis through tumor cell-intrinsic mechanisms, such as cancer cell invasion, migration and epithelial-mesenchymal transition, and tumor cell-extrinsic mechanisms. This multifaceted role in cancer progression and metastasis makes RAGE a promising therapeutic target in the prevention and treatment of breast cancer. Here we tested the preclinical anti-metastasic efficacy of two small molecule RAGE inhibitors; TTP48 (Azeliragon) and FPS-ZM1. Importantly, TTP488 displays a high safety profile in human trials and has previously undergone Phase 3 clinical trials for Alzheimer’s disease. While FPS-ZM1 is a well-known RAGE inhibitor in preclinical cancer models, TTP488 has not been tested for its anti-cancer activity in breast cancer. Methods: We tested the in vitro anti-metastatic effect of TTP488 and FPS-ZM1 on cancer cell migration and invasion in Boyden chamber assays with TNBC cell lines (MDA-MB-231 and 4T-1). We used the 4175 highly metastatic MDA-MB-231 variant in xenograft studies in NSG mice to test the efficacy of the RAGE inhibitors in vivo on tumor progression and metastasis. Experimental metastasis assays were performed with tail-vein injection of 4T-1 cells into BALBc mice. We performed bulk RNA sequencing on the MDA-MB-231/4175/NSG tumors to unveil and compare the mechanism of action of the two small molecule RAGE inhibitors. Results: Our results showed that TTP488 and FPS-ZM1 impaired mechanisms of metastasis in vitro with both MDA-MB231/4175 and 4T-1 cells. TTP488 and FPS-ZM1 significantly inhibited MDA-MB231/4175 cell metastasis from the orthotopic site in NSG mice without displaying any deleterious effects on mouse health. In the syngeneic 4T-1/BALBc model, both TTP488 and FPS-ZM1 impaired metastasis in tail-vein injected experimental metastasis assays. Transcriptomic analysis of primary xenograft tumors from NSG mice revealed that TTP488 and FPS-ZM1 displayed high concordance in gene expression changes. Pathway enrichment analysis showed that both RAGE inhibitors affected metastatic pathways, including focal adhesion, ECM-receptor interaction, cell cycle, and DNA replication. Conclusions: These results show that TTP488 impairs metastasis of multiple highly aggressive TNBC models for the first time. Importantly, as TTP488 displays a high safety profile in human trials, this study provides the rationale for evaluating TTP488 in clinical trials to treat or prevent metastatic breast cancer.

Citation Format: Melinda Magna, Gyong Ha Hwang, Alec McIntosh, Katherine Drews-Elger, Masaru Takabatake, Barbara Mera, Taekyoung Kwak, Philip Miller, Marc Lippman, Barry I. Hudson. Azeliragon (TTP488), an orally- available small molecule RAGE inhibitor, reduces metastasis in preclinical mouse models of breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-08-10.

A pilot randomized sham controlled trial of bilateral iTBS for depression and executive function in older adults

INTRODUCTION

Executive function deficits (EFD) in late life depression (LLD) are associated with poor outcomes. Dysfunction of the cognitive control network (CCN) has been posited in the pathophysiology of LLD with EFD.

METHODS

Seventeen older adults with depression and EFD were randomized to iTBS or sham for 6 weeks. Intervention was delivered bilaterally using a recognized connectivity target.

RESULTS

A total of 89% (17/19) participants completed all study procedures. No serious adverse events occurred. Pre to post-intervention change in mean Montgomery-Asberg-depression scores was not different between iTBS or sham, p = 0.33. No significant group-by-time interaction for Montgomery-Asberg Depression rating scale scores (F _{3, 44}  = 0.51; p = 0.67) was found. No significant differences were seen in the effects of time between the two groups on executive measures: Flanker scores (F _{1, 14}  = 0.02, p = 0.88), Dimensional-change-card-sort scores F _{1, 14}  = 0.25, p = 0.63, and working memory scores (F _{1, 14}  = 0.98, p = 0.34). The Group-by-time interaction effect for functional connectivity (FC) within the Fronto-parietal-network was not significant (F _{1, 14}  = 0.36, p = 0.56). No significant difference in the effect-of-time between the two groups was found on FC within the Cingulo-opercular-network (F _{1, 14}  = 0, p = 0.98).

CONCLUSION

Bilateral iTBS is feasible in LLD. Preliminary results are unsupportive of efficacy on depression, executive function or target engagement of the CCN. A future Randomized clinical trial requires a larger sample size with stratification of cognitive and executive variables and refinement in the target engagement.

Temperature-controlled Laminar Airflow (TLA) in symptomatic severe asthma – a post hoc analysis of severe exacerbations, quality of life and health economics

Purpose

Uncontrolled severe asthma constitutes a major economic burden to society. Add-ons to standard inhaled treatments include inexpensive oral corticosteroids and expensive biologics. Nocturnal treatment with Temperature-controlled Laminar Airflow (TLA; Airsonett®) could be an effective, safe and cheaper alternative. The potential of TLA in reducing severe asthma exacerbations was addressed in a recent randomised placebo-controlled trial (RCT) in patients with severe asthma (Global Initiative for Asthma (GINA) step 4/5), but the results were inconclusive. We re-analysed the RCT with severe exacerbations stratified by the level of baseline asthma symptoms and Quality of Life.

Methods

More uncontrolled patients, defined by Asthma Control Questionnaire 7 (ACQ7) > 3, EuroQoL 5-Dimension Questionnaire Visual Analogue Scale (EQ5D-VAS) ≤ 65 and Asthma Quality of Life Questionnaire (AQLQ) ≤ 4 were selected for re-analysis. The rates of severe asthma exacerbations, changes in QoL and health-economics were analysed and compared between TLA and placebo.

Results

The study population included 226 patients (113 TLA / 113 placebo.) The rates of severe asthma exacerbations were reduced by 33, 31 and 25% (p = 0.083, 0.073, 0.180) for TLA compared to placebo, dependent on selected control measures (ACQ7, EQ5D-VAS, AQLQ, respectively). For patients with less control defined by AQLQ≤4, the difference in mean AQLQ0-12M between TLA and placebo was 0.31, 0.33, 0.26 (p = 0.085, 0.034, 0.150), dependent on selected covariate (AQLQ, EQ5D-VAS, ACQ7, respectively). For patients with poor control defined by ACQ7 > 3, the difference in EQ5D-5 L utility scores between TLA and placebo was significant at 9 and 12 months with a cost-effective ICER. The results from the original study did not demonstrate these differences.

Conclusion

This post hoc analysis demonstrated an effect of TLA over placebo on severe exacerbations, asthma control and health economics in a subgroup of patients with more symptomatic severe allergic asthma. The results are consistent with the present recommendations for TLA. However, these differences were not demonstrated in the full study. Several explanations for the different outcomes have been outlined, which should be addressed in future studies.

Funding

NIHR Health Technology Assessment Programme and Portsmouth Hospitals NHS Trust.

147 ESTABLISHING A PERI-OPERATIVE MEDICAL SERVICE (POMS) FOR OLDER PEOPLE IN UROLOGY

Background

Older adults account for approximately 65% of patients undergoing urological procedures therefore as the population ages the demand is anticipated to rise. The benefits of Comprehensive Geriatric Assessment (CGA) have been proven in ortho-geriatrics and a number of surgical specialties but evidence in urology is lacking. The aim of this study was to assess the impact of a Peri-Operative Medical Service for older people (POMS) on patient outcomes in a urology inpatient population.

Methods

This was a single-centre retrospective study of patients ≥50 years with length of stay (LOS) &gt;1 day admitted over two four month periods in 2018 (Pre-intervention) and 2019 (Intervention). Group differences in LOS and complications were examined using univariate regressions and then adjusted for sex, emergency admission, severity of procedure and Charlson Co-morbidity Index which also accounts for age. Secondary outcomes were to record undiagnosed medical conditions identified and the interventions made by the POMS.

Results

There were a total of 218 admissions from 211 patients with equal numbers of admissions in both the pre-intervention and intervention groups. No significant differences were detected for LOS (median 3 vs 4 days, p=0.11) or complications (32(29%) vs 40(37%), p=0.23) between pre-intervention and intervention groups. A new medical diagnosis was made in 13 (12%) of the pre-intervention v 43(39%) of the intervention group (p&lt;0.001). The POMS recommended a change to management in 102 admissions (94%). The most common intervention was medication review: 64(59%) v 19(17%) (p&lt;0.001).

Conclusion

The Peri-Operative Medical Service for older people can improve patient management by identifying and managing medical issues, complications and geriatric syndromes that may otherwise have been missed.

Evaluation of plasma nucleosome concentrations in dogs with a variety of common cancers and in healthy dogs

Background

Cell free DNA, in the form of nucleosomes, is released into circulation during apoptosis and necrosis in a variety of diseases. They are small fragments of chromosomes that are composed of DNA wrapped around a histone core made of four duplicate histone proteins forming an octamer. The nucleosome compartment is a relatively uninvestigated area of circulating tumor biomarkers in dogs. The objectives of this study were to quantify and better characterize nucleosome concentrations in 528 dogs with various common malignancies and compare them to 134 healthy dogs.

Results

The sensitivity of increased circulating nucleosome concentrations for the detection of cancer in all dogs was 49.8% with a specificity of 97% with an area under the curve of 68.74%. The top 4 malignancies detected by the test included lymphoma, hemangiosarcoma, histiocytic sarcoma and malignant melanoma. The malignancies least likely to be detected were soft tissue sarcomas, osteosarcoma and mast cell tumors.

Conclusions

A variety of tumor types may cause increased nucleosome concentrations in dogs. Tumors of hematopoietic origin are most likely to cause elevations and local tumors such as soft tissue sarcomas are least likely to cause elevations in plasma nucleosome concentrations.

Abstract P5-06-08: Triple-negative breast cancer CAFs induce a metastatic phenotype in MCF-7 cells via the SDF-1/CXCR4 axis

Background: Metastatic disease is the foremost cause of breast cancer (BC) related mortality in women. One of the crucial challenges in reducing metastasis-related mortality is in identifying and understanding why certain BCs metastasize and recur. Although cancer cell-intrinsic factors are a key determinant in BC metastasis, host-intrinsic factors like the cells of the tumor microenvironment (TME), such as cancer-associated fibroblasts (CAFs) are what might be driving certain BCs to metastasize and recur. We recently showed that CAFs from the primary (TME) enter into circulation as cCAFs, form heterotypic clusters with tumor cells, and arrive at metastatic sites. This interaction between CAFs and tumor cells is crucial in furthering the metastatic cascade. However, the functional heterogeneity of the different CAF phenotypes and how that impacts BC metastasis is unknown. Stromal derived factor-1 (SDF-1/CXCL12) is an important chemokine that is known to be involved in promoting tumor cell invasion and metastasis. In this study, we examine the functional differences between CAF isolated from different molecular subtypes of BC. Furthermore, we elucidate the role of CAF secreted SDF-1 as being one of the mechanisms by which a subset of CAF cells permanently reprograms poorly-metastatic MCF-7 cells to augment EMT-driven genes and become metastatic in vivo. Methods: We used primary CAF cell lines derived from BCs of different molecular subtypes and examined their global gene expression profiles using RNAseq. We used NSG mice xenografted with MCF-7 BC cells and primary CAF cells to evaluate the contribution of two different CAF phenotypes in promoting BC progression and metastasis. We developed dissociated tumor cell lines from CAF co-injected MCF-7 xenografts to determine the molecular changes that CAFs impart to MCF-7 cells in vivo. Using limiting dilution tumor xenograft assays and gene expression profiles we examined the molecular pathways, BC stemness markers, and tumor-initiating capacity of the dissociated tumor cell lines. By long-term SDF-1 treatment of MCF-7 cells in vitro and using these cells in various RNASeq, in vitro, and in vivo assays we determined the role of SDF-1 in altering the phenotype of MCF-7 cells. Results: We found that CAFs from different molecular subtypes have a differential effect on tumor initiation, progression, and metastasis in xenograft assays. We also found that a subset of CAFs has the ability to make the poorly-metastatic MCF-7 cells metastatic in vivo. We also found that this subset of CAF cells has a higher expression of SDF-1 and the tumors formed with the co-injection of MCF-7 cells with this subset of CAF cells are enriched in cancer stem cell-like metastasis initiating cells. We also found that upon serial transplant, the tumors formed by CAF-reprogramed MCF-7 cells have a gene expression profile that shows enrichment for EMT-driven genes and these tumors are robustly metastatic. Furthermore, we found that the SDF-1/CXCR4 axis is one of the critical mechanisms by which this subset of CAF cells permanently reprograms the phenotype of the MCF-7 cells. Conclusions: CAFs are a highly heterogeneous population of cells in the breast TME. This study examines the contribution of the functional heterogeneity of the CAF cells in BC metastasis. We have found that a unique subset of CAF cells has the ability to reprogram a poorly metastatic BC cell to not only become metastatic but induce a permanent EMT-driven phenotypic shift in the BC cells. SDF-1 may be one of the mechanisms that drive this CAF-induced change and understanding the CAF functional landscape and its role in BC metastasis might be crucial to developing new therapeutic modalities to abrogate BC metastasis.

Citation Format: Utsav Sharma, Jun Sun, Kelsie Medina-Saenz, Susan Bare, Philip Miller, Manuel Picon-Ruiz, Joyce Slingerland, Dorraya El-Ashry, Marc Lippman. Triple-negative breast cancer CAFs induce a metastatic phenotype in MCF-7 cells via the SDF-1/CXCR4 axis [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-06-08.

Abstract PS19-04: Standard temperature husbandry increases tumor aggressiveness via chronic cold stress in murine mammary cancer models

Correct interpretation of disease progression and therapeutic responses in mouse models of breast cancer requires interrogation of models and conditions that faithfully recapitulate human disease and conditions that mimic clinical intervention. Historically, standard temperature (ST) for in vivo murine research has been approximately 70-72°F (21-22°C), mimicking ambient temperatures in laboratories that are comfortable for researchers. However, previous work from the Repasky lab demonstrated that ST housing results in chronic cold stress and immune suppression mediated by an increase in norepinrephrine (NE) levels, leading to increased tumor aggressiveness. In contrast, syngeneic murine mammary tumors in mice housed at higher temperatures [~ 82°F] grew more slowly and resulted in fewer metastases. Based on these findings, we investigated tumor progression and metastasis in a temperature dose response in two syngeneic murine mammary tumor models: the balb/c-4T1 model and the c57bl6/E0771-LMB (a lung metastatic variant of E0771 cells) model.Mice were acclimatized in rooms with three different ambient temperaures and challenged with tumor cells. ST was maintained at 70-72°F, while mid-temperature (MT) was maintained at 78-80°F, and high temperature (HT) was maintained at 84-85°F. Compared to ST and MT, an ambient temperature of 84-85°F resulted in a statistically significant delay in tumor formation and decreased primary tumor growth by unpaired t-test (p=.0006) At day 13, when 4T1 tumors are typically well-initiated and measurable by caliper, mean tumor volumes in the ST-housed mice were significantly larger than the HT group. At day 21, ST tumors means were 4 times larger than HT. In the E0771-LMB model, mean tumor volumes on day 14 were nearly 3 times larger in ST-housed mice than HT. At day 27, the mean tumor volumes were 2 times larger in the ST group compared to HT-housed mice. Data on metastasis will be presented at the meeting. Mean NE levels in mice housed at ST were twice as high as those at HT, providing ancillary evidence that traditional “standard” temperatures are a significant stressor for mice (p=.0091).These data demonstrate the potential for misleading interpretations of biological significance of chronic cold stress when modeling immunocompetent tumor progression [conditions almost universally employed in most studies]. Furthermore, these data demonstrate that the presence of chronic cold stress and its immunosuppressive effects call into question the interpretation of many previous studies completed at or near standard temperature and may suggest the need to increase ambient temperatures in syngeneic experiments in order to more accurately model human disease.

Citation Format: Darius O Gaymon, Marc Lippman, Patricia Foley, Philip Miller. Standard temperature husbandry increases tumor aggressiveness via chronic cold stress in murine mammary cancer models [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS19-04.

OP0297 EFFICACY AND SAFETY OF ROMOSOZUMAB AMONG POSTMENOPAUSAL WOMEN WITH OSTEOPOROSIS AND MILD-TO-MODERATE CHRONIC KIDNEY DISEASE

Background:

Osteoporosis and renal insufficiency are coexisting disease states in a substantial proportion of postmenopausal women. Since bisphosphonates are generally contraindicated in patients with estimated glomerular filtration rate (eGFR) <35 mL/min, it is important to evaluate other osteoporosis treatments in this setting.

Objectives:

To determine if baseline renal function affects the efficacy and safety of romosozumab.

Methods:

We performed post hoc analyses of two clinical trials of romosozumab in postmenopausal women with osteoporosis. In ARCH (NCT01631214), 4,093 patients were randomised 1:1 to romosozumab 210 mg monthly or alendronate 70 mg weekly for 12 months (mean age: 74.3 years; 96.1% with prevalent vertebral fractures [VFx]). In FRAME (NCT01575834), 7,180 patients were randomised 1:1 to romosozumab 210 mg or placebo monthly for 12 months (mean age: 70.9 years; 18.3% with prevalent VFx). For these analyses, patients were categorised by baseline eGFR (mL/min/1.73m2): normal renal function (eGFR ≥90), mild renal insufficiency (eGFR 60–89), or moderate renal insufficiency (eGFR 30–59). Least squares mean (LSM) percent change from baseline in bone mineral density (BMD) at the lumbar spine, total hip, and femoral neck; incidence of new VFx and adverse events (AEs); and changes in renal function were assessed for each eGFR category at Month 12 of the double-blind treatment period.

Results:

At baseline, most patients had mild/moderate renal insufficiency: 84% in ARCH, 88% in FRAME. In both studies, change from baseline in BMD was significantly higher in the romosozumab group across baseline eGFR categories (Figure). There was an interaction between BMD increase and renal function, and although BMD increase was not as large in women with impaired renal function, differences between romosozumab and control groups remained significant (Figure). In ARCH, among patients with eGFR ≥90, 60–89, and 30–59, the incidence of new VFx (romosozumab vs alendronate) at Month 12 was 3.3% vs 7.3%, 3.2% vs 3.9%, and 3.4% vs 6.2% in ARCH. In FRAME, the incidence of new VFx (romosozumab vs placebo) at Month 12 was 0.5% vs 3.0%, 0.4% vs 1.5%, and 0.6% vs 2.1%.

In both studies, the incidences of AEs and serious AEs were similar in both treatment groups within and across eGFR categories. AEs of mild-to-moderate hypocalcaemia (investigator reported) occurred in two patients in ARCH (one romosozumab [eGFR 60–89] and one alendronate [eGFR ≥90]), and one patient in FRAME (romosozumab [eGFR 60–89]). Five patients in ARCH (all in the alendronate group) and 19 patients in FRAME (14 romosozumab, 5 placebo) had decreases in serum Ca levels (albumin adjusted); in the romosozumab group all were mild (<LLN–8.0 mg/dL) or moderate (<8.0–7.0 mg/dL). A similar percentage of patients in each group had changes in renal function over 12 months of treatment.

Conclusion:

The efficacy and safety of romosozumab vs alendronate or placebo was similar among postmenopausal women with osteoporosis and different levels of renal function.

Acknowledgments:

This study was funded by Amgen, Astellas and UCB Pharma. Editorial services were provided by Costello Medical.

Disclosure of Interests:

Paul Miller Grant/research support from: Amgen, Radius Health, Ultragenyx, Consultant of: Amgen, Radius Health, Jonathan Adachi Consultant of: Amgen, Speakers bureau: Amgen, Ben-Hur Albergaria Consultant of: Amgen Inc., Eli Lilly, Speakers bureau: Amgen Inc., Eli Lilly, Angela M Cheung Consultant of: Amgen, Eli Lilly, Arkadi Chines Shareholder of: Amgen Inc., Employee of: Amgen Inc., Evelien Gielen Consultant of: Amgen Inc., Takeda, Sandoz and UCB Pharma, Speakers bureau: Amgen Inc., Takeda, Sandoz and UCB Pharma, Bente Langdahl Grant/research support from: Amgen, NovoNordisk, Consultant of: Amgen Inc., Eli Lilly, UCB Pharma, Akimitsu Miyauchi Consultant of: Amgen Inc., Astellas BioPharma K.K., Teijin Pharma, Mary Oates Shareholder of: Amgen Inc., Employee of: Amgen Inc., Ian Reid Consultant of: Amgen Inc., Eli Lilly, Speakers bureau: Amgen Inc., Eli Lilly, Norma Ruiz Santiago Shareholder of: Amgen Inc., Employee of: Amgen Inc., Mark Vanderkelen Employee of: UCB Pharma, Wenjing Yang Shareholder of: Amgen Inc., Employee of: Amgen Inc., Zhigang Yu Shareholder of: Amgen Inc., Employee of: Amgen Inc.

Sapphire advanced mitigation process: wet etch to expose sub-surface damage and increase laser damage resistance and mechanical strength

A novel, to the best of our knowledge, method of wet chemical etching of sapphire workpieces (such as optics, wafers, windows, and cones), called the sapphire advanced mitigation process (or sapphire AMP), has been developed that exposes sub-surface mechanical damage created during the optical fabrication process and significantly enhances the surface laser damage resistance ($ \gt {2{\times}}$>2×) and mechanical strength (up to $\sim{2.6{\times}}$∼2.6×). Sapphire AMP involves first treating the workpiece with a mixture of sulfuric and phosphoric acid $([{\rm H_{2}{\rm SO_{4}}}]:[{\rm H_{3}{\rm PO_{4}}}]=1:3)$([H₂SO₄]:[H₃PO₄]=1:3) at 220°C, followed with phosphoric acid at 160°C, then with sodium hydroxide base (NaOH) and surfactant at 40°C, and finally with a high-pressure deionized water spray rinse. Sapphire AMP has been demonstrated on both A- and C-plane sapphire workpieces. The mechanism of this etch process involves the reaction of the sapphire $({\rm Al_{2}}{\rm O_{3}})$(Al₂O₃) surface with sulfuric acid $({\rm H_{2}}{\rm SO_{4}})$(H₂SO₄) forming aluminum sulfate $[{{\rm Al}_2}{({{\rm SO}_4})_3}]$[Al₂(SO₄)₃], which has low solubility. The high phosphoric acid content in the first and second steps of sapphire AMP results in the efficient conversion of ${{\rm Al}_2}{({{\rm SO}_4})_3}$Al₂(SO₄)₃ to aluminum phosphate $({\rm AlPO_{4}})$(AlPO₄), which is very soluble, greatly reducing reaction product redeposition on the workpiece surface. Sapphire AMP is shown to expose sub-surface mechanical damage on the sapphire surface created during the grinding and polishing processes, whose etched morphology has either isotropic or anisotropic evolution depending on the nature of the initial surface damage. Sapphire AMP was also designed to remove the key known surface, laser absorbing precursors (namely, foreign chemical impurities, the fracture surface layer of preexisting sub-surface damage, and reaction product or foreign species redeposition or precipitation). Static and sliding indention induced surface microfractures on sapphire are shown after sapphire AMP to have a significant decrease in the fast photoluminescence intensity (a known metric for measuring the degree of laser damaging absorbing precursors). In addition, the onset of laser damage (at 351 nm 3 ns) on sapphire AMP treated workpieces was shown to increase in fluence from $\sim{4}$∼4 to $ \gt {9}.{5}\;{{\rm J/cm}^2}$>9.5J/cm². Finally, biaxial ball-on-ring mechanical tests on sapphire disks showed an increase in the failure stress from 340 MPa (with pre-existing 28 µm flaws) to $\sim{900}\;{\rm MPa}$∼900MPa after sapphire AMP, which is attributed to the blunting of the surface microfractures.

Breeding Centers, Private Ranches, and Genomics for Creating Sustainable Wildlife Populations

Human-induced changes to environments are causing species declines. Beyond preserving habitat (in situ), insurance (ex situ) populations are essential to prevent species extinctions. The Conservation Centers for Species Survival (C2S2) is leveraging space of breeding centers and private ranches to produce “source populations”—genetically diverse reservoirs that also support research and reintroductions. The initial focus is on four African antelopes. C2S2 has developed a program, the Source Population Alliance, that emphasizes animals living in spacious, naturalistic conditions in greater numbers than can be accommodated by urban zoos. Simulation modeling demonstrates how herds can rapidly increase population abundance and retain genetic diversity. Advances in genomics and resulting DNA data allow monitoring of genetic diversity and parentage as well as refined decision-making. This approach, neither pure in situ nor ex situ, but rather “sorta situ”, is an innovative way of linking public and private sector resources to ensure that endangered species survive.

Abstract 2044: CD44 facilitates metastasis by promoting co-clustering of breast cancer cells and cancer associated fibroblasts

Background: Transport of tumor cells via the circulation (CTCs) is a key step in metastasis. CTC clusters and in particular, cancer stem cell-like cell (cCSC) clusters exhibit enhanced metastatic capacity over individual CTCs or cCSCs. Cancer associated fibroblasts (CAFs) are critical players in the breast tumor microenvironment (TME) and are also found in metastases. In clinical and pre-clinical studies, we have identified circulating CAFs (cCAFs) and cCAF/CTC co-clusters as potential biomarkers for breast cancer progression and metastasis. Our data suggest that the ability of breast cancer cells (BCCs) to cluster with CAFs depends on their intrinsic metastatic capacity, and specifically, their CSC-like phenotype, characterized by expression of the CD44 cell surface marker: both in vivo and in in vitro cluster assays, only metastatic BCCs could form co-clusters while non-metastatic BCCs could not. Further, both in vivo and in vitro, co-clustering potential was marked by a stem cell-like phenotype, including increased CD44 expression. We hypothesize that cCAF/cCSC co-clusters are the functional units of metastasis. The goal of this current study is to identify mechanisms that influence co-clustering between CTCs and cCAFs and specifically to investigate the role of CD44 in co-clustering.

Methods: Co- and mono-clusters of CAFs and BCCs were established in vitro by plating equal numbers of CAFs/BCCs into ultra-low attachment plates. After 24 hrs, clusters were collected and injected into female NSG mice via tail vein. Metastases was monitored by IVIS and confirmed by IHC. Mice were sacrificed at specific time points and blood collected by cardiac puncture. In vitro-generated clusters and blood were filtered using the faCTCheker microfluidic filtration instrument (Circulogix) to capture circulating cells with an 8-micron pore filter. Filters were stained by immunofluorescence for tumor cells, CAFs, and CD44. Hyaluronin (HA) was visualized with biotinylated HA binding protein. anti-CD44 siRNA (Dharmacon smart pool) was used to knockdown CD44 in BCCs or in CAFs

Results: Injection of CAF/BCC co-clusters resulted in accelerated metastases compared to mono-cluster injection. In both co-clusters captured from mouse blood and established in vitro, HA, a CD44 ligand secreted by CAFs as well as produced by cancer cells, was observed. Elimination of HA in CAFs and BCCs reduced co-cluster formation. Knockdown of CD44 expression in BCCs via siRNA abrogated BCC co-clustering ability.

Conclusion: In vitro and in vivo models of induced and conditional knockout of CD44 are defining the role of cancer cell-autonomous or CAF-autonomous CD44 in cCAF/CTC co-clustering and BC metastasis. These studies implicate CD44 as a driver of co-clustering between BCCs and CAFs. Inactivation of CD44 may abrogate co-clustering as well as impair the CSC phenotype, thus impacting critical pathways in BCC metastasis.

Citation Format: Benjamin Troness, Angela Spartz, Utsav Sharma, Philip Miller, Kelsie Medina Saenz, Marc Lippman, James McCarthy, Dorraya El-Ashry. CD44 facilitates metastasis by promoting co-clustering of breast cancer cells and cancer associated fibroblasts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2044.

Suicide risk and social support in Australian resource sector employees: A cross-sectional study

This study examines the association between suicide risk and social support in Australian resource sector employees. We included 150 participants, who completed the Beck Hopelessness Scale and MOS-Social Support Survey. Data were analyzed using smallest space analysis and multidimensional scalogram analysis. The analysis identified four distinct regions, which were conceptualized as "confiding," "affection," "companionship," and "practical help." All of these components of social support were associated with hopelessness, which has important clinical implications as hopelessness is related to suicide risk. The results of this study also demonstrated that lower levels of social support, and greater sense of perceived hopelessness tended to lead to Australian resource workers seeking assistance from mental health professionals in the previous year. Attention should turn towards providing interventions that promote social support for employees in Australian resource industry.

Abstract P4-01-07: A comprehensive liquid biopsy in patients undergoing neoadjuvant therapy

Background: Precision medicine is revolutionizing breast cancer (BC) care. Comprehensive liquid biopsies are a tool for personalized care in patients with locally advanced breast cancer (LABC). Identifying robust biomarkers as part of a comprehensive liquid biopsy to predict response to treatment is of immense clinical interest.

Methods: After obtaining IRB approval, serial blood samples were collected from patients with LABC undergoing neoadjuvant therapy. Paired biopsies were collected prior to treatment and were sent to Foundation Medicine for next-generation sequencing (NGS). We used a sized-base microfilter technology to capture circulating tumor cells (CTCs) and circulating cancer associated fibroblasts (cCAFs). Patients with one or more CTCs or cCAFs were deemed positive for these tests. Additionally, in collaboration with Foundation Medicine, we extracted circulating tumor DNA (ctDNA) and we analyzed it using the FoundationACT platform. Patients with a detectable genomic alteration in their plasma were considered as having a positive ctDNA test. Our primary objective is to determine if a comprehensive liquid biopsy can serve as a prognostic marker of pathologic complete response (pCR).

Results: For this analysis we describe our findings in the initial blood draw of the first 18 patients enrolled. The mean age is 54 years (38-70). All patients who had their tumors sequenced had a detectable mutation. Consistent with the findings of others, we found TP53 mutations to be the most prevalent at 83.3%. We found that 44% of patients had ctDNA, 68.4% had cCAFs and 78.9% had CTCs. Many patients also had clusters of cells, consisting of one cell type, or co-clusters, consisting of both. 38.9% had CTC clusters, 16.7% had cCAF clusters and 16.7% had co-clusters (CTCs and cCAFs together). Some patients with CTCs did not have cCAFs and vice versa. The number of CTCs and cCAFS did not correlate with stage of disease or receptor status.

Conclusions: We describe a comprehensive liquid biopsy combining a sized-based microfilter technology for CTC and cCAFs identification and the FoundationACT platform for ctDNA analysis is feasible and these biomarkers can be detected in patients with LABC prior to the initiation of neoadjuvant therapy. Our study is accruing rapidly, and we will update our results with the longitudinal collection and the prognostic value of a comprehensive liquid biopsy at the time of the meeting.

Citation Format: Sandoval Leon AC, Medina Saenz K, Miller P, Benson A, Calfa C, Mahtani R, Slingerland J, Perez A, Vogel C, Valdes-Albini F, El-Ashry D, Lippman M. A comprehensive liquid biopsy in patients undergoing neoadjuvant therapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-07.

Abstract PD9-10: Circulating CAF/cancer stem cell co-clusters bolster breast cancer metastasis

Background: Metastatic disease is the primary cause of breast cancer (BC) mortality. Cancer associated fibroblasts (CAFs) are the majority of stroma in BC and critical players in BC malignancy. For example, CAFs are the main source of SDF-1, a prominent chemokine in the tumor microenvironment (TME) that also imparts stem cell-like characteristics to BC cells. Metastasis occurs due to the transport of circulating tumor cells (CTC) and clusters of CTCs through the vasculature. Stem-like CTCs and clusters have a greater propensity to establish metastasis. We recently identified circulating CAFs (cCAFs) in blood from patients with BC and in spontaneous, syngeneic, and xenograft mouse models of BC. cCAFs not only circulate individually, but are also found in clusters with CTCs. In this study, we examine the role of CAFs in promoting egress of stem-like CTCs (cCSCs), determine the capacity of stem-like CTCs to cluster with CAFs, and evaluate the involvement of CTC/cCAF clustering in augmenting BC metastasis.

Methods: Our model employs NSG mice with orthotopic xenograft implantation of BC cells, primary CAF cell lines, or co-implantation of BC and CAF cell lines. We used two different BC cell lines: the non-metastatic BC cell line, MCF-7, and the highly metastatic primary BC cell line, DT28. We also employed the MMTV-PyMT spontaneous model of BC metastasis, and we used BALB/c mice injected with syngeneic 4T1 or 67nR cells to evaluate cCAFs, CTCs, and cluster egress in preclinical models. Mice were sacrificed at specific time points, and cardiac blood was collected. Blood was filtered using the faCTChecker microfluidic filtration instrument (Circulogix). Filters were stained for IF and cCAFs, CTCs, cCSCs, and clusters were enumerated. Tumors from CAF co-injected mice were evaluated for their stem cell-like phenotype and re-implanted in mice to evaluate tumorigenicity and metastasis.

Results: In spontaneous, syngeneic, and orthotopic xenograft models of BC, cCAFs, CTCs, and cCAF/CTCs co-clusters appear early in tumor development. cCAF/CTC clusters increase in correlation with tumor burden and metastasis. Co-inoculation of CAFs with BC cells resulted in a significant increase in tumor progression, metastasis, and in a substantially higher number of both individual cells and clusters in circulation. Dissociated tumor cells from CAF co-injected tumors had a higher proportion of CD44+stem cell-like cells (CSCs), enhanced ALDH-1 expression, and enhanced mammosphere formation. CD44+ CSCs, individually and in clusters, are found early on in the circulation of mice injected with dissociated tumor cells from CAF co-injected tumors. Upon re-implantation of CAF co-injected dissociated tumor cells without CAFs, dissociated tumor cells showed enhanced tumorigenicity and malignancy.

Conclusion: CAFs are highly motile and cCAFs precede CTCs into circulation and can do so independently of tumor cells. CAFs sustain egress of tumor cells by augmenting malignancy and stemness of BC cells. cCAF clusters with the highly metastatic stem cell-like subset of CTCs bolster metastatic colonization. Targeting primary CAF function and/or cCAF/cCSC co-clusters may provide novel avenues to abrogate BC metastasis.

Citation Format: Sharma U, Miller P, Medina Saenz K, Picon-Ruiz M, Morata-Tarifa C, Spartz A, Troness B, Park DN, Seagroves TN, Slingerland JM, Lippman ME, El-Ashry D. Circulating CAF/cancer stem cell co-clusters bolster breast cancer metastasis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD9-10.

A comparison of screw versus drill and curettage epiphysiodesis to correct leg-length discrepancy

PURPOSE

To compare two common surgical techniques of epiphysiodesis: drill/curettage epiphysiodesis (PDED) versus cross screw epiphysiodesis (PETS). The hypothesis is that the two techniques have similar efficacy but demonstrate differences in length of hospital stay (LOS), time to return to activity and complication rates.

METHODS

A retrospective review of growing children and adolescents less than 18 years old who required an epiphysiodesis with leg-length discrepancy (LLD) of 2 cm to 6 cm with minimum two years of follow-up was conducted. Characteristics including age at surgery, gender, epiphysiodesis location, side, operative time, LOS and hardware removal were compared across treatment groups. LLD, expected growth remaining (EGR) and bone age were determined preoperatively and at most-recent visit. The correction ratio (change in EGR) was calculated along with a 95% confidence interval (CI) to assess if correction in leg length was achieved.

RESULTS

A total of 115 patients underwent epiphysiodesis in the femur (53%), tibia (24%) or a combination (24%). The cohort was 47% male, with a mean age of 12.6 years (7.7 to 17.7) at surgery. Median follow-up was 3.7 years (2.0 to 12.7). In all, 23 patients underwent PETS and 92 patients had PDED. Both treatment groups achieved expected LLD correction. There was no significant difference in median operative time, complication rates or LOS. PETS patients returned to activity at a mean 1.4 months (interquartile range (IQR) 0.7 to 2.1) while PDED patients returned at a mean 2.4 months (IQR 1.7 to 3) (p < 0.001).

CONCLUSION

Effectiveness in achieving expected correction, LOS and operative time are similar between screw and drill/curettage epiphysiodesis. Patients undergoing PETS demonstrated a faster return to baseline activity than patients with PDED.

LEVEL OF EVIDENCE

III.

Abstract 5062: CAFs in breast cancer circulation: The influence of cancer cell intrinsic mechanisms

Background: Metastatic disease is the primary cause of breast cancer (BC) mortality. Tumor-stromal cell interactions play a pivotal in tumor initiation, progression and metastasis. Cancer-associated fibroblasts (CAFs) are the majority of stroma in BC and are critical to BC tumorigenicity and malignancy. Metastasis occurs due to the transport of circulating tumor cells (CTC) and clusters of CTCs through the vasculature. We recently identified circulating CAFs (cCAFs) as a novel circulating biomarker associated with metastatic BC. cCAFs not only circulate individually, in BC patient blood and in blood from both spontaneous and xenograft murine BC models, but cCAFs are also found in clusters with CTCs. In this study, we examine the egress of CAFs and follow them through to metastatic sites, and evaluate the ability of BC cell subtype/metastatic propensity to influence cCAF and cCAF/CTC cluster egress.

Methods: We used NSG mice with orthotopic xenograft implantation of BC cells, primary CAF cell lines, or co-implantation of BC and CAF cell lines. We used two different BC cell lines, the nonmetastatic BC cell line, MCF-7, and the highly metastatic primary BC cell line, DT28. We also employed the MMTV-PyMT spontaneous model of BC metastasis to evaluate cCAFs and CTCs in a preclinical model. Mice were sacrificed at specific time points, and cardiac blood was collected to ascertain the temporal dynamics of cCAF and CTC presence. Blood was filtered using the faCTChecker microfluidic filtration instrument (Circulogix). Filters were enumerated by IF for cCAFs, CTCs, and cCAF/CTC co-clusters. To explore BC-intrinsic factors that influence cCAF and cCAF/CTC cluster egress, we modeled egress from the primary tumor in vitro using transendothelial cell migration assays, where the chemoattractant for CAF cells was conditioned media from the different BC cells lines.

Results: In both spontaneous and orthotopic xenograft models of BC, cCAFs, CTCs, and cCAF/CTCs appear early in tumor development. cCAF/CTC clusters increase in correlation with tumor burden and metastasis. CAFs injected alone in orthotopic xenografts are able to egress independently of BC cells and cCAFs and cCAF clusters were seen; however, co-inoculation with BC cells resulted in substantially higher numbers of both individual cCAFs and cCAF clusters, and now co-clusters were seen. cCAFs appear about 4 days post-injection, and precede appearance of CTCs and CAF/CTC clusters. CAFs co-injected with BC cells into the MFP appear at metastatic sites. In in vitro transendothelial assays, BC secreted factors that potentiate CAF egress are identified as well as the if cCAF/CTC clusters egress as clusters or cluster in the circulation.

Conclusion: Although CAFs are highly motile and cCAFs precede CTCs into the circulation, BC subtype influences the ability of CAFs to egress. Targeting cCAF egress and/or cCAF/BC cell clusters provides novel avenues to prevent or treat BC metastasis.

Citation Format: Utsav Sharma, Philip Miller, Kelsie Medina Saenz, Angela Spartz, Marc Lippman, Dorraya El-Ashry. CAFs in breast cancer circulation: The influence of cancer cell intrinsic mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5062.

A Novel Piperazine-Based Drug Lead for Cryptosporidiosis from the Medicines for Malaria Venture Open-Access Malaria Box

Cryptosporidiosis causes life-threatening diarrhea in children under the age of 5 years and prolonged diarrhea in immunodeficient people, especially AIDS patients. The standard of care, nitazoxanide, is modestly effective in children and ineffective in immunocompromised individuals. In addition to the need for new drugs, better knowledge of drug properties that drive in vivo efficacy is needed to facilitate drug development. We report the identification of a piperazine-based lead compound for Cryptosporidium drug development, MMV665917, and a new pharmacodynamic method used for its characterization. The identification of MMV665917 from the Medicines for Malaria Venture Malaria Box was followed by dose-response studies, in vitro toxicity studies, and structure-activity relationship studies using commercial analogues. The potency of this compound against Cryptosporidium parvum Iowa and field isolates was comparable to that against Cryptosporidium hominis Furthermore, unlike nitazoxanide, clofazimine, and paromomycin, MMV665917 appeared to be curative in a NOD SCID gamma mouse model of chronic cryptosporidiosis. MMV665917 was also efficacious in a gamma interferon knockout mouse model of acute cryptosporidiosis. To determine if efficacy in this mouse model of chronic infection might relate to whether compounds are parasiticidal or parasitistatic for C. parvum, we developed a novel in vitro parasite persistence assay. This assay suggested that MMV665917 was parasiticidal, unlike nitazoxanide, clofazimine, and paromomycin. The assay also enabled determination of the concentration of the compound required to maximize the rate of parasite elimination. This time-kill assay can be used to prioritize early-stage Cryptosporidium drug leads and may aid in planning in vivo efficacy experiments. Collectively, these results identify MMV665917 as a promising lead and establish a new method for characterizing potential anticryptosporidial agents.

Abstract P2-01-10: Circulating CAF/CTC complexes and breast cancer metastasis

Background: Metastatic disease in breast cancer (BC) is the leading cause of cancer-related mortality among women worldwide. Synergy between cancer cells and non-cancer cells of the tumor microenvironment (TME) are vital for disease progression. Cancer associated fibroblasts (CAFs) are the major cell type in the stroma of BC and are critical mediators of tumor progression and metastasis. Transport of circulating tumor cells (CTCs) and CTC clusters through the vasculature seeds metastasis and clinical and preclinical studies demonstrate that CTC clusters have a higher metastatic potential than individual CTCs. More recently, circulating cancer stem cells (cCSCs) have been implicated as more metastatic than non-CSC CTCs. In our lab, we have demonstrated that CAFs also circulate (cCAFs). We have observed cCAFs in peripheral blood from breast cancer patients and in murine models of breast cancer. Furthermore, we have observed that cCAFs are present in circulation as both individual cells and as well as in complexes with CTCs. Given the integral role of CAFs in BC metastasis, we hypothesize that cCAFs complex with CTCs/cCSCs to bolster BC metastasis.

Methods: cCAF/CTC clusters were identified and enumerated from peripheral blood of patients with BC, and associations with clinical features and disease outcomes were evaluated. Blood was collected by cardiac puncture from PyMT mice from 4 weeks through to the presence of metastases (10 weeks) and cCAF/CTC clusters enumerated. We co-injected CAFs with MCF-7 cellsl into NSG mice, blood collected by cardiac puncture, and cCAF/CTC clusters were enumerated. At time of final sacrifice, tumors were removed and assessed for presence of CSCs. Using our established model of cCAF/CTC clustering in vitro we interrogated cCAF/CTC complexing with both metastatic and poorly metastatic BC cells.

Results: Circulating cCAFs/CTCs clusters are significantly increased in the blood of patients with advanced stage BC and associate not only with severity of disease but also with poorer clinical outcomes. In the spontaneous PyMT mouse model, the appearance of circulating cCAF/CTC clusters increased significantly as tumors grew but prior to metastasis. We demonstrate that metastatic BC cells form clusters with CAFs in vitro while non-metastatic BC cells do not form complexes with CAFs in vitro. Enriching for stem cells from MCF7 mammospheres, resulted in CAF/CSC clusters in vitro. In mice that were co-injected with non-metastatic MCF7 cells and CAFs from a TNBC/Basal-like BC (CAF23) we observed disease metastasis, an enrichment for cancer stem cell (CSC)-like CTCs, and the presence of circulating cCAF/MCF7-CSC clusters.

Conclusions: Circulating clusters of CTCs and cCAFs are characteristic, and potentially causative, of BC metastasis. Observations of cCAF/CTC clusters from preclinical and clinical samples are corroborated by our determination that the ability of BC cells to form complexes with CAFs in vitro is related to the intrinsic metastatic ability of the breast cancer cells. Both in vitro and in circulation, the BC cells in cCAF/cBC clusters are CSCs, so cCAF/cCSC clusters. Disrupting the formation of cCAF/CTC complexes may be a potential strategy to reduce treat or prevent breast cancer metastasis.

Citation Format: Miller P, Sharma U, Medina-Saenz K, Yeasky T, Picon-Ruiz M, Morata-Tarifa C, Seagroves T, Slingerland J, Lippman M, El-Ashry D. Circulating CAF/CTC complexes and breast cancer metastasis [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-01-10.

Elevated S100A8 protein expression in breast cancer cells and breast tumor stroma is prognostic of poor disease outcome

PURPOSE

Elevated S100A8 expression has been observed in cancers of the bladder, esophagus, colon, ovary, and breast. S100A8 is expressed by breast cancer cells as well as by infiltrating immune and myeloid cells. Here we investigate the association of elevated S100A8 protein expression in breast cancer cells and in breast tumor stroma with survival outcomes in a cohort of breast cancer patients.

PATIENTS AND METHODS

Tissue microarrays (TMA) were constructed from breast cancer specimens from 417 patients with stage I-III breast cancer treated at the University of Michigan Comprehensive Cancer Center between 2004 and 2006. Representative regions of non-necrotic tumor and distant normal tissue from each patient were used to construct the TMA. Automated quantitative immunofluorescence (AQUA) was used to measure S100A8 protein expression, and samples were scored for breast cancer cell and stromal S100A8 expression. S100A8 staining intensity was assessed as a continuous value and by exploratory dichotomous cutoffs. Associations between breast cancer cell and stromal S100A8 expression with disease-free survival and overall survival were determined using the Kaplan-Meier method and Cox proportional hazard models.

RESULTS

High breast cancer cell S100A8 protein expression (as indicated by AQUA scores), as a continuous measure, was a significant prognostic factor for OS [univariable hazard ratio (HR) 1.24, 95% confidence interval (CI) 1.00-1.55, p = 0.05] in this patient cohort. Exploratory analyses identified optimal S100A8 AQUA score cutoffs within the breast cancer cell and stromal compartments that significantly separated survival curves for the complete cohort. Elevated breast cancer cell and stromal S100A8 expression, indicated by higher S100A8 AQUA scores, significantly associates with poorer breast cancer outcomes, regardless of estrogen receptor status.

CONCLUSIONS

Elevated breast cancer cell and stromal S1008 protein expression are significant indicators of poorer outcomes in early stage breast cancer patients. Evaluation of S100A8 protein expression may provide additional prognostic information beyond traditional breast cancer prognostic biomarkers.

Abstract 5895: Circulating CAF and cCAF circulating tumor cell co clusters are associated with metastatic breast cancer

Background: Breast cancer metastasis is the cause of breast cancer-related mortality. The tumor microenvironment (TME) plays a critical role in governing tumor initiation, progression and metastasis. In breast cancer, cancer associated fibroblasts (CAFs) are master regulators of the TME. Cancer metastasis occurs in part by transport of circulating tumor cells (CTCs) in the circulation. CTCs in clusters, rather than individual CTCs, have a greater capacity to establish metastases. We recently demonstrated that CAFs also circulate (cCAFs), both in clusters with CTCs and individually, in the blood of the majority of breast cancer patients with metastases, some patients without overt metastases, and in no patients with no evidence of disease. Our lab has also established primary breast cancer and primary CAF cell lines from dissociated breast tumors of different molecular subtypes; these are ideal models to dissect tumor-stromal interactions, both in vitro and in vivo. We hypothesize that cCAFs originate from the primary tumor, and further, that cCAFs cluster with CTCs to facilitate metastatic seeding.

Methods: We used separately labeled CAFs and primary breast cancer cells (DT28) co-injected into NSG mice and followed by a novel 2-color IVIS. We also modeled the ability of CAFs and breast cancer cells to form clusters in culture and used our microfluidic filter technology to evaluate the composition of clusters resulting from admixed CAFs and BC cells of differing metastatic capacity – metastatic DT28 and non-metastatic MCF-7.

Results: Through sequential dual-color IVIS we demonstrate that we can monitor the presence of CAFs and breast cancer cells at orthotopic tumor injection sites and to sites of distant metastasis, indicating that cCAFs originate from the primary tumor. Evaluation of cCAFs and CTCs in tumor bearing mice indicates that breast cancer cells with high metastatic potential mobilize greater numbers of cCAFs. CAFs formed robust clusters with metastatic DT28 cells, while non-metastatic MCF-7 cells clustered with each other but not with CAFs suggesting that the ability of breast cancer cells to form clusters with CAFs, both in vitro and in vivo, is reflective of the metastatic capability of the breast cancer cell line.

Conclusions: The intrinsic metastatic capabilities of breast cancer cells are augmented by contact and clustering with cCAFs. In turn, the ability of CAFs to mobilize into circulation is in part conferred by properties of aggressive breast cancer cells. These data corroborate observations from our pilot clinical study that indicated the presence of cCAFs is overwhelmingly associated with the presence of metastatic breast cancer.

Citation Format: Utsav Sharma, Philip Miller, Kelsie Medina-Saenz, Pedro Ferrer, Svetlana Speransky, Toni Yeasky, Dorraya El-Ashry. Circulating CAF and cCAF circulating tumor cell co clusters are associated with metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5895. doi:10.1158/1538-7445.AM2017-5895

The use of mesoscale eddies by juvenile loggerhead sea turtles (Caretta caretta) in the southwestern Atlantic

Marine animals, such as turtles, seabirds and pelagic fishes, are observed to travel and congregate around eddies in the open ocean. Mesoscale eddies, large swirling ocean vortices with radius scales of approximately 50–100 km, provide environmental variability that can structure these populations. In this study, we investigate the use of mesoscale eddies by 24 individual juvenile loggerhead sea turtles (Caretta caretta) in the Brazil-Malvinas Confluence region. The influence of eddies on turtles is assessed by collocating the turtle trajectories to the tracks of mesoscale eddies identified in maps of sea level anomaly. Juvenile loggerhead sea turtles are significantly more likely to be located in the interiors of anticyclones in this region. The distribution of surface drifters in eddy interiors reveals no significant association with the interiors of cyclones or anticyclones, suggesting higher prevalence of turtles in anticyclones is a result of their behavior. In the southern portion of the Brazil-Malvinas Confluence region, turtle swimming speed is significantly slower in the interiors of anticyclones, when compared to the periphery, suggesting that these turtles are possibly feeding on prey items associated with anomalously low near-surface chlorophyll concentrations observed in those features.

Abstract P4-12-13: High intratumoral and stromal S100A8 expression is prognostic of poor outcome in breast cancer

Background: S100A8 and S100A9 are members of a family of calcium binding proteins that regulate inflammatory response, and are biomarkers of inflammatory diseases, S100A8/A9 preferentially form heterodimers that interact with their receptor, RAGE, to activate signaling pathways (ERK1/2 MAPK, JNK, and NF-κB) and stimulate tumor cells. Elevated expression of S100A8/A9 has been observed in cancers of the bladder, esophagus, colon, ovary, and breast. S100A8/A9 are expressed intratumorally by cancer cells and in the stroma by infiltrating immune and myeloid cells as well. We investigated the associations of elevated expression of intratumoral and stromal S100A8 with survival outcomes in breast cancer.

Methods: Tissue microarrays (TMA) were constructed from breast cancer specimens from patients with stage I-III breast cancer treated at the University of Michigan Comprehensive Cancer Center between 2004-2006, ensuring a minimum of 10-year follow-up. Each patient was represented on the TMA by representative regions of non-necrotic tumor and distant normal tissue. Automative Quantitative Immunofluorescence (AQUA) was performed for S100A8 protein, and samples were scored for intratumoral and stromal S100A8 expression. S100A8 staining was assessed as a continuous value and by exploratory dichotomous cutoffs. Associations with disease-free survival (DFS) or overall survival (OS) and S100A8 expression, either as continuous value or based on the exploratory cutoffs, were determined using the Kaplan-Meier method and Cox proportional hazards models.

Results: In the entire patient cohort, high intratumoral S100A8 expression, as a continuous measure, was a significant prognostic factor for OS (univariable hazard ratio [HR] 1.26, 95% confidence interval [CI] 1.02-1.56, p=0.036), and for DFS (multivariable HR [95%CI] = 1.24 [1.01-1.53], p = 0.043). Exploratory analyses demonstrated optimal cutoffs of intratumoral and intrastromal staining that greatly separated survival curves. We evaluated whether the prognostic significance of S100A8 expression is different in breast cancer patients based on hormone receptor status and determined that neither intratumoral nor stromal S100A8 expression were significantly associated with outcomes.

Conclusions: Elevated intratumoral and stromal expression of S100A8 are significant indicators of poor outcome in breast cancer patients. These data further support a biological role for S100A8 signaling in mammary carcinogenesis and aggressive tumor behavior. Evaluation of S100A8 protein expression might provide additional prognostic information beyond traditional breast cancer prognostic biomarkers. Further validation is necessary to investigate these findings.

Citation Format: Miller P, Kidwell K, Thomas D, Sabel M, Rae J, Hayes DF, Lippman ME, El-Ashry D. High intratumoral and stromal S100A8 expression is prognostic of poor outcome in breast cancer [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 P4-12-13.

Abstract P4-03-18: A hierarchy of cancer associated fibroblasts in situ and in circulation promote breast cancer metastasis

Background: Metastasis is the primary cause of breast cancer mortality. Interactions between cancer cells and non-cancer cells of the tumor microenvironment (TME) are pivotal in governing tumor initiation, progression and metastasis, and cancer associated fibroblasts (CAFs) are critical orchestrators of these interactions. We recently identified circulating CAFs (cCAFs) as a novel circulating biomarker associated with metastatic breast cancer. We established CAF cell lines from dissociated luminal A, ER- Her-2 amplified, and triple-negative/basal-like (TN) breast tumors. We demonstrated that “aggressive” CAFs differentially secrete miRNAs that contribute to ER-negativity, activated growth factor signaling, and induction of EMT in breast cancers compared to “indolent” CAFs. We hypothesized that a hierarchy exists within CAFs regarding their ability to facilitate tumor progression and metastasis. Here we demonstrate that CAFs derived from aggressive TN breast tumors differ from those derived from more indolent Luminal A breast tumors in secretion of cytokines and chemokines that can confer differential effects on the behavior of breast cancer cells. We also demonstrate that “aggressive” CAFs more potently facilitate tumor progression and metastasis than “indolent” CAFs. We additionally evaluated if “aggressive” and “indolent” CAFs differ in their ability to mobilize CTCs and circulating CAFs into circulation.

Methods: Conditioned media (CM) from “aggressive” and “indolent” CAFs was analyzed for chemokine/cytokine expression. Luminal A breast cancer cells (MCF-7) or primary tumor cells from an aggressive TN tumor (DT28) were injected into the mammary fat pad of 6-8 week old female NSG mice, either alone or in combination with CAF19-I or CAF23-A. Tumor progression was monitored and mice were examined for metastasis at necropsy. Tissues were harvested for histology and blood was collected by cardiac puncture. Plasma was analyzed for cytokine/chemokine expression and blood was processed for enumeration of circulating tumor cells (CTCs) and cCAFs.

Results: “Aggressive” CAF CM had significantly higher levels of a number of factors, including IL-8, SDF-1, and CXCL1, compared to “indolent” CAF CM. MCF-7 cells co-injected with “aggressive” CAFs formed tumors much faster than those co-injected with the “indolent” CAFs or without CAFs. While DT28 cells readily form tumors and metastasize in the NSG model, fewer DT28 cells do not form metastases in the timeframe that this same lower number of DT28 cells co-injected with “aggressive” CAFs demonstrated robust tumor growth and developed metastases in liver and pancreas. DT28 cells co-injected with “indolent” CAFs did not exhibit metastases.

Conclusion: The data presented here further demonstrate that there is a hierarchy within CAFs regarding their ability to facilitate tumor growth and metastasis, and that this may largely be mediated by secreted soluble factors. “Aggressive” CAFs may retain their programmed role in circulation and accelerate metastasis more than “indolent” CAFs. We suggest that targeting CAFs in situ and in circulation and disrupting their interactions with breast cancer cells could provide novel strategies to combat breast cancer and breast cancer metastasis.

Citation Format: Sharma U, Miller P, Speransky S, Medina-Saenz K, Ferrer P, Lippman M, El-Ashry D. A hierarchy of cancer associated fibroblasts in situ and in circulation promote breast cancer metastasis [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 P4-03-18.

ASPP2 deficiency causes features of 1q41q42 microdeletion syndrome

Chromosomal abnormalities are implicated in a substantial number of human developmental syndromes, but for many such disorders little is known about the causative genes. The recently described 1q41q42 microdeletion syndrome is characterized by characteristic dysmorphic features, intellectual disability and brain morphological abnormalities, but the precise genetic basis for these abnormalities remains unknown. Here, our detailed analysis of the genetic abnormalities of 1q41q42 microdeletion cases identified TP53BP2, which encodes apoptosis-stimulating protein of p53 2 (ASPP2), as a candidate gene for brain abnormalities. Consistent with this, Trp53bp2-deficient mice show dilation of lateral ventricles resembling the phenotype of 1q41q42 microdeletion patients. Trp53bp2 deficiency causes 100% neonatal lethality in the C57BL/6 background associated with a high incidence of neural tube defects and a range of developmental abnormalities such as congenital heart defects, coloboma, microphthalmia, urogenital and craniofacial abnormalities. Interestingly, abnormalities show a high degree of overlap with 1q41q42 microdeletion-associated abnormalities. These findings identify TP53BP2 as a strong candidate causative gene for central nervous system (CNS) defects in 1q41q42 microdeletion syndrome, and open new avenues for investigation of the mechanisms underlying CNS abnormalities.

Long-term non-invasive interrogation of human dorsal root ganglion neuronal cultures on an integrated microfluidic multielectrode array platform

Scientific studies in drug development and toxicology rely heavily on animal models, which often inaccurately predict the true response for human exposure. This may lead to unanticipated adverse effects or misidentified risks that result in, for example, drug candidate elimination. The utilization of human cells and tissues for in vitro physiological platforms has become a growing area of interest to bridge this gap and to more accurately predict human responses to drugs and toxins. The effects of new drugs and toxins on the peripheral nervous system are often investigated with neurons isolated from dorsal root ganglia (DRG), typically with one-time measurement techniques such as patch clamping. Here, we report the use of our multi-electrode array (MEA) platform for long-term noninvasive assessment of human DRG cell health and function. In this study, we acquired simultaneous optical and electrophysiological measurements from primary human DRG neurons upon chemical stimulation repeatedly through day in vitro (DIV) 23. Distinct chemical signatures were noted for the cellular responses evoked by each chemical stimulus. Additionally, the cell viability and function of the human DRG neurons were consistent through DIV 23. To the best of our knowledge, this is the first report on long-term measurements of the cell health and function of human DRG neurons on a MEA platform. Future generations will include higher electrode numbers in customized arrangements as well as integration with different tissue types on a single device. This platform will provide a valuable testing tool for both rodent and human cells, enabling a more comprehensive risk assessment for drug candidates and toxicants.

Is the tiger shark Galeocerdo cuvier a coastal species? Expanding its distribution range in the Atlantic Ocean using at-sea observer data

The occurrence of tiger shark Galeocerdo cuvier in the Atlantic Ocean was assessed using at-sea observer data from multiple pelagic longline fisheries. Geographic positions of 2764 G. cuvier recorded between 1992 and 2013 and covering a wide area of the Atlantic Ocean were compared with the currently accepted distribution ranges of the species. Most records fell outside those ranges in both the Southern and Northern Hemispheres, which strongly suggests that the distribution range of G. cuvier in the open ocean is considerably larger than previously described.

Abstract P2-06-03: Leukemia inhibitory factor receptor as a tumor suppressor: A study on migration and invasion of breast cancer cells upon LIFR stimulation

BACKGROUND: Tumorigenesis is the result of a step-wise process during which a mutation activates an oncogene or inactivates a tumor suppressor gene. Identification of these genes is critical in order to develop effective therapies for breast cancer patients. Our group previously discovered the Leukemia Inhibitory Factor Receptor (LIFR) as a novel tumor suppressor gene via an in vivo RNAi screen in HMLE cells. HMLE is a partially transformed non-tumorigenic cell line; these cells can become tumorigenic with a single mutation, such as the Ras mutation that creates the HMLER line. HMLEs were transduced using an shRNA library targeting the entire human genome, and stably transfected cells were xenografted into NOD/SCID mice. Genomic DNA from resultant primary tumors were analyzed for the shRNA sequences that, when integrated, made HMLEs tumorigenic. LIFR emerged from this screen as a novel candidate tumor suppressor gene in breast cancer. Here we report on the decreased migration and invasion of breast cancer cells activated by LIFR stimulation.

METHODS: HMLER cells were plated at 500,000 cells per well of a six-well plate. Twenty-four hours later, HMLERs were treated with 100, 25, 12.5, 5, 2.5, or 0 ng/ml recombinant hLIF. Protein lysates were analyzed for phospho-STAT3 induction upon LIF stimulation. Based on the results, we selected 25 ng/ml as the appropriate hLIF concentration to maximally stimulate LIFR in the migration assay described here. HMLERs were serum starved for 8 hours. DMEM with 10% fetal bovine serum was added to the bottom of the migration assay plate as a chemoattractant. The cells were suspended in DMEM with 0.1% bovine serum albumin and either treated with 25 ng/ml LIF or no LIF. Thereafter, 25,000 cells were added to either a Corning Biocoat Matrigel Invasion Chamber or a control insert lacking a migration matrix. The migration assay plate was incubated at 37°C and the cells were allowed to migrate for 20 hours. Migrated cells were enumerated under the light microscope and a migration percentage was calculated.

RESULTS: In the first portion of the study, we found that low concentrations of LIF (2.5 ng/ml) resulted in p-STAT3 induction in HMLERs, but that p-STAT3 was maximally induced with 25 ng/ml of LIF. In the invasion and migration assay, HMLER cells that had not been treated with LIF displayed an aggressively invasive and migratory phenotype with 61.1% migration in matrigel compared to control inserts without the migration matrix. When HMLERs were treated with 25 ng/ml LIF, the cells displayed decreased invasion and migration with only 50.0% of cells migrating. Based on these results, LIFR stimulation inhibits the invasion and migration of breast cancer cells.

CONCLUSIONS: As a tumor suppressor gene, LIFR is vital to the normal functioning of a non-cancerous cell, and its loss can produce a tumorigenic and metastatic phenotype. Treatment with LIF converts aggressively metastatic breast cancer cells to a less invasive phenotype. Through a deeper understanding of LIFR's tumor suppressor effects, we can harness the anti-tumorigenic and anti-metastatic properties of LIFR stimulation and develop targeted therapies to prevent growth and metastasis of breast cancer.

Citation Format: Dempsey NG, Miller P, Lippman M. Leukemia inhibitory factor receptor as a tumor suppressor: A study on migration and invasion of breast cancer cells upon LIFR stimulation. [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 P2-06-03.

BiGG Models: A platform for integrating, standardizing and sharing genome-scale models

Genome-scale metabolic models are mathematically-structured knowledge bases that can be used to predict metabolic pathway usage and growth phenotypes. Furthermore, they can generate and test hypotheses when integrated with experimental data. To maximize the value of these models, centralized repositories of high-quality models must be established, models must adhere to established standards and model components must be linked to relevant databases. Tools for model visualization further enhance their utility. To meet these needs, we present BiGG Models (http://bigg.ucsd.edu), a completely redesigned Biochemical, Genetic and Genomic knowledge base. BiGG Models contains more than 75 high-quality, manually-curated genome-scale metabolic models. On the website, users can browse, search and visualize models. BiGG Models connects genome-scale models to genome annotations and external databases. Reaction and metabolite identifiers have been standardized across models to conform to community standards and enable rapid comparison across models. Furthermore, BiGG Models provides a comprehensive application programming interface for accessing BiGG Models with modeling and analysis tools. As a resource for highly curated, standardized and accessible models of metabolism, BiGG Models will facilitate diverse systems biology studies and support knowledge-based analysis of diverse experimental data.