Migratory Propensity Research Articles

Abstract 5083: A comprehensive workflow for screening and real-time analysis of cell invasion

Abstract Cell migration and invasion are crucial steps in many normal, as well as, aberrant physiological processes, in particular, the highly lethal metastatic progression of cancer. Once the normally restrictive basement membrane boundaries of the tumor have been breached, invasive cells can gain access to the vasculature and lymphatic system permitting systemic spread of the disease. Invasion is a complex multistep process involving cell adhesion, directed migration, and proteolytic degradation of surrounding extracellular matrix (ECM) barriers. Multiple factors present in the local microenvironment, including soluble growth factors or chemokines and ECM-anchored integrins and proteases, act coordinately to regulate the invasive potential. Understanding the cellular and molecular mechanisms underlying invasion is essential to the development of therapeutics that target tumor metastasis. Therefore, techniques for the quantification and dynamic visualization of penetrating cells have become central to oncology research. The most widely employed method for analyzing cell invasion in vitro is a modified Boyden chamber assay using Matrigel, a basement membrane matrix preparation. While amenable to semi-quantitative “screening” assays, these systems suffer from the inability to establish continuous gradients. As a result, this method, such gradients cannot be stably maintained under static culturing conditions, precluding longer-term real-time cell analysis. Moreover, these platforms are not strictly designed for microscope-based visualization and thus cannot be employed for dynamic mechanistic studies through imaging analysis at the inter- and intra-cellular levels. Here we present a two-tiered platform for the analysis of cell invasion. Cell culture insert plates (24 and 96-well capacity), provide the ideal tool for initial compound screening for functional response (inhibit invasion) and toxicity. For selected compounds, mechanistic studies were then performed using a microfluidic-based system. The platform consists of a microfluidic culture plate and environmental control system; the latter regulates matrix loading, media perfusion, the establishment of stable continuous concentration gradients within the plate, as well as temperature and gas control. Most significantly, the plate can be paired with an inverted microscope enabling dynamic analysis of cell movement in real-time. Fluorescent visualization further permits selective discrimination of unique cell types in heterogeneous samples as well as changes in expression patterns of labeled proteins. In summary, the combined workflow platform presented here provides a framework for studying the effects of signaling molecules and growth factors on the migratory and invasive propensities of tumors cells. Citation Format: Amedeo J. Cappione, Timothy Nadler. A comprehensive workflow for screening and real-time analysis of cell invasion. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5083.

Modeling vector-borne disease risk in migratory animals under climate change.

Recent theory suggests that animals that migrate to breed at higher latitudes may benefit from reduced pressure from natural enemies, including pathogens ("migratory escape"), and that migration itself weeds out infected individuals and lowers infection prevalence ("migratory culling"). The distribution and activity period of arthropod disease vectors in temperate regions is expected to respond rapidly to climate change, which could reduce the potential for migratory escape. However, climate change could have the opposite effect of reducing transmission if differential responses in the phenology and distribution of migrants and disease vectors reduce their overlap in space and time. Here we outline a simple modeling framework for exploring the influence of climate change on vector-borne disease dynamics in a migratory host. We investigate two scenarios under which pathogen transmission dynamics might be mediated by climate change: (1) vectors respond more rapidly than migrants to advancing phenology at temperate breeding sites, causing peak susceptible host density and vector emergence to diverge ("migratory mismatch") and (2) reduced migratory propensity allows increased nonbreeding survival of infected hosts and larger breeding-site epidemics (loss of migratory culling, here referred to as "sedentary amplification"). Our results highlight the need for continued surveillance of climate-induced changes to migratory behavior and vector activity to predict pathogen prevalence and its impacts on migratory animals.

Escaping peril: perceived predation risk affects migratory propensity.

Although migratory plasticity is increasingly documented, the ecological drivers of plasticity are not well understood. Predation risk can influence migratory dynamics, but whether seasonal migrants can adjust their migratory behaviour according to perceived risk is unknown. We used electronic tags to record the migration of individual roach (Rutilus rutilus), a partially migratory fish, in the wild following exposure to manipulation of direct (predator presence/absence) and indirect (high/low roach density) perceived predation risk in experimental mesocosms. Following exposure, we released fish in their lake summer habitat and monitored individual migration to connected streams over an entire season. Individuals exposed to increased perceived direct predation risk (i.e. a live predator) showed a higher migratory propensity but no change in migratory timing, while indirect risk (i.e. roach density) affected timing but not propensity showing that elevated risk carried over to alter migratory behaviour in the wild. Our key finding demonstrates predator-driven migratory plasticity, highlighting the powerful role of predation risk for migratory decision-making and dynamics.

Low-Molecular-Weight Protein Tyrosine Phosphatase Predicts Prostate Cancer Outcome by Increasing the Metastatic Potential

BackgroundLow-risk patients suffering from prostate cancer (PCa) are currently placed under active surveillance rather than undergoing radical prostatectomy. However, clear parameters for selecting the right patient for each strategy are not available, and new biomarkers and treatment modalities are needed. Low-molecular-weight protein tyrosine phosphatase (LMWPTP) could present such a target. ObjectiveTo correlate expression levels of LMWPTP in primary PCa to clinical outcome, and determine the role of LMWPTP in prostate tumor cell biology. Design, setting, and participantsAcid phosphatase 1, soluble (ACP1) expression was analyzed on microarray data sets, which were subsequently used in Ingenuity Pathway Analysis. Immunohistochemistry was performed on a tissue microarray containing material of 481 PCa patients whose clinicopathologic data were recorded. PCa cell line models were used to investigate the role of LMWPTP in cell proliferation, migration, adhesion, and anoikis resistance. Outcome measurements and statistical analysisThe association between LMWPTP expression and clinical and pathologic outcomes was calculated using chi-square correlations and multivariable Cox regression analysis. Functional consequences of LMWPTP overexpression or downregulation were determined using migration and adhesion assays, confocal microscopy, Western blotting, and proliferation assays. Results and limitationsLMWPTP expression was significantly increased in human PCa and correlated with earlier recurrence of disease (hazard ratio [HR]:1.99; p<0.001) and reduced patient survival (HR: 1.53; p=0.04). Unbiased Ingenuity analysis comparing cancer and normal prostate suggests migratory propensities in PCa. Indeed, overexpression of LMWPTP increases PCa cell migration, anoikis resistance, and reduces activation of focal adhesion kinase/paxillin, corresponding to decreased adherence. ConclusionsOverexpression of LMWPTP in PCa confers a malignant phenotype with worse clinical outcome. Prospective follow-up should determine the clinical potential of LMWPTP overexpression. Patient summaryThese findings implicate low-molecular-weight protein tyrosine phosphatase as a novel oncogene in prostate cancer and could offer the possibility of using this protein as biomarker or target for treatment of this disease.

Shape up or ship out: migratory behaviour predicts morphology across spatial scale in a freshwater fish.

1. Migration is a widespread phenomenon, with powerful ecological and evolutionary consequences. Morphological adaptations to reduce the energetic costs associated with migratory transport are commonly documented for migratory species. However, few studies have investigated whether variation in body morphology can be explained by variation in migratory strategy within a species. 2. We address this question in roach Rutilus rutilus, a partially migratory freshwater fish that migrates from lakes into streams during winter. We both compare body shape between populations that differ in migratory opportunity (open vs. closed lakes), and between individuals from a single population that vary in migratory propensity (migrants and residents from a partially migratory population). Following hydrodynamic theory, we posit that migrants should have a more shallow body depth, to reduce the costs associated with migrating into streams with higher flow conditions than the lakes the residents occupy all year round. 3. We find evidence both across and within populations to support our prediction, with individuals from open lakes and migrants from the partially migratory population having a more slender, shallow-bodied morphology than fish from closed lakes and all-year residents. 4. Our data suggest that a shallow body morphology is beneficial to migratory individuals and our study is one of the first to link migratory strategy and intraspecific variation in body shape.

Quantitative genetics of migration-related traits in rainbow and steelhead trout.

Rainbow trout (Oncorhynchus mykiss) exhibit remarkable life history diversity throughout their native range, and among the most evident is variation in migratory propensity. Although some populations and ecotypes will remain resident in freshwater habitats throughout their life history, others have the ability to undertake tremendous marine migrations. Those that migrate undergo a suite of behavioral, morphological, and physiological adaptations in a process called smoltification. We describe a quantitative genetic analysis of 22 growth, size, and morphological traits in addition to overall life history classification (resident or migrant) over the temporal process of smoltification in a large multi-generation experimental pedigree (n = 16,139) of migratory and resident rainbow trout derived from a wild population, which naturally segregates for migratory propensity. We identify significant additive genetic variance and covariance among the suite of traits that make up a component of the migratory syndrome in this species. Additionally, we identify high heritability estimates for the life history classifications and observe a strong negative genetic correlation between the migratory and resident life history trajectories. Given the large heritability estimates of all of the traits that segregate between migratory and resident rainbow trout, we conclude that these traits can respond to selection. However, given the high degree of genetic correlation between these traits, they do not evolve in isolation, but rather as a suite of coordinated characters in a predictable manner.

Effects of larval density and food stress on life‐history traits of Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

AbstractHigh population density and nutrition restriction can lead to phase variation in morphology and development, and subsequently induce changes in the reaction norms of adult flight in migrant insects. However, response of migratory propensity to such stress in Endopterygote insects, especially in several species of Lepidoptera, remains unclear. In this study, larval and adult developmental responses to crowding and food stress were investigated in the migratory moth, Cnaphalocrocis medinalis (Guenée). A high larval rearing density significantly reduced pupal mass, survival rate and female fecundity. Larvae developed rapidly under crowding conditions, and time to pupation was 2 days earlier than individuals reared alone. By contrast, short‐term starvation and associated compensatory growth prolonged larval duration by 3–4 days and pupal duration by 1–2 days. It also reduced the pupal mass, but showed no detectable effects on female reproductive performance. Both sexes had similar development strategies; however, females seemed to be more sensitive to crowding and food shortage than males. A positive effect was expected if such stress factors acted as cues that triggering a behavioural or physiological shift to a distinct migratory phase. To the contrary, we found no proof that crowding and starvation caused maturation delay in female reproductive development. All treatments did not significantly increase female pre‐oviposition period. Therefore, we concluded that life developmental responses to crowding and food shortage in this species were different. Adult migration propensity was not enhanced under such stress conditions during the larval phase.

Divergence in expression of candidate genes for the smoltification process between juvenile resident rainbow and anadromous steelhead trout.

Rainbow and steelhead trout (Oncorhynchus mykiss), among other salmonid fishes, exhibit tremendous life history diversity, foremost of which is variation in migratory propensity. While some individuals possess the ability to undertake an anadromous marine migration, others remain resident in freshwater throughout their life cycle. Those that will migrate undergo tremendous physiological, morphological, and behavioral transformations in a process called smoltification which transitions freshwater-adapted parr to marine-adapted smolts. While the behavior, ecology, and physiology of smoltification are well described, our understanding of the proximate genetic mechanisms that trigger the process are not well known. Quantitative genetic analyses have identified several genomic regions associated with smoltification and migration-related traits within this species. Here we investigate the divergence in gene expression of 18 functional and positional candidate genes for the smoltification process in the brain, gill, and liver tissues of migratory smolts, resident parr, and precocious mature male trout at the developmental stage of out-migration. Our analysis reveals several genes differentially expressed between life history classes and validates the candidate nature of several genes in the parr-smolt transformation including Clock1α, FSHβ, GR, GH2, GHR1, GHR2, NDK7, p53, SC6a7, Taldo1, THRα, THRβ, and Vdac2.

Extreme Heterogeneity in Parasitism Despite Low Population Genetic Structure among Monarch Butterflies Inhabiting the Hawaiian Islands

Host movement and spatial structure can strongly influence the ecology and evolution of infectious diseases, with limited host movement potentially leading to high spatial heterogeneity in infection. Monarch butterflies (Danaus plexippus) are best known for undertaking a spectacular long-distance migration in eastern North America; however, they also form non-migratory populations that breed year-round in milder climates such as Hawaii and other tropical locations. Prior work showed an inverse relationship between monarch migratory propensity and the prevalence of the protozoan parasite, Ophryocystis elektroscirrha. Here, we sampled monarchs from replicate sites within each of four Hawaiian Islands to ask whether these populations show consistently high prevalence of the protozoan parasite as seen for monarchs from several other non-migratory populations. Counter to our predictions, we observed striking spatial heterogeneity in parasite prevalence, with infection rates per site ranging from 4–85%. We next used microsatellite markers to ask whether the observed variation in infection might be explained by limited host movement and spatial sub-structuring among sites. Our results showed that monarchs across the Hawaiian Islands form one admixed population, supporting high gene flow among sites. Moreover, measures of individual-level genetic diversity did not predict host infection status, as might be expected if more inbred hosts harbored higher parasite loads. These results suggest that other factors such as landscape-level environmental variation or colonization-extinction processes might instead cause the extreme heterogeneity in monarch butterfly infection observed here.

Greater migratory propensity in hosts lowers pathogen transmission and impacts

Animal migrations are spectacular and migratory species have been shown to transmit pathogens that pose risks to human health. Although migration is commonly assumed to enhance pathogen dispersal, empirical work indicates that migration can often have the opposite effect of lowering disease risk. Key to assessing disease threats to migratory species is the ability to predict how migratory behaviour influences pathogen invasion success and impacts on migratory hosts, thus motivating a mechanistic understanding of migratory host-pathogen interactions. Here, we develop a quantitative framework to examine pathogen transmission in animals that undergo two-way directed migrations between wintering and breeding grounds annually. Using the case of a pathogen transmitted during the host's breeding season, we show that a more extreme migratory strategy (defined by the time spent away from the breeding site and the total distance migrated) lowers the probability of pathogen invasion. Moreover, if migration substantially lowers the survival probability of infected animals, then populations that spend comparatively less time at the breeding site or that migrate longer distances are less vulnerable to pathogen-induced population declines. These findings provide theoretical support for two non-exclusive mechanisms proposed to explain how seasonal migration can lower infection risk: (i) escape from habitats where parasite transmission stages have accumulated and (ii) selective removal of infected hosts during strenuous journeys. Our work further suggests that barriers to long-distance movement could increase pathogen prevalence for vulnerable species, an effect already seen in some animal species undergoing anthropogenically induced migratory shifts.

Fixed and Flexible: Coexistence of Obligate and Facultative Migratory Strategies in a Freshwater Fish

Migration is an important event in many animal life histories, but the degree to which individual animals participate in seasonal migrations often varies within populations. The powerful ecological and evolutionary consequences of such partial migration are now well documented, but the underlying mechanisms are still heavily debated. One potential mechanism of partial migration is between-individual variation in body condition, where animals in poor condition cannot pay the costs of migration and hence adopt a resident strategy. However, underlying intrinsic traits may overrule such environmental influence, dictating individual consistency in migratory patterns. Unfortunately, field tests of individual consistency compared to the importance of individual condition on migratory propensity are rare. Here we analyse 6 years of field data on roach migration, gathered by tagging almost 3000 individual fish and monitoring their seasonal migrations over extended periods of time. Our aims were to provide a field test of the role of condition in wild fish for migratory decisions, and also to assess individual consistency in migratory tendency. Our analyses reveal that (1) migratory strategy, in terms of migration/residency, is highly consistent within individuals over time and (2) there is a positive relationship between condition and the probability of migration, but only in individuals that adopt a migratory strategy at some point during their lives. However, life-long residents do not differ in condition to migrants, hence body condition is only a good predictor of migratory tendency in fish with migratory phenotypes and not a more general determinant of migratory tendency for the population. As resident individuals can achieve very high body condition and still remain resident, we suggest that our data provides some of the first field evidence to show that both facultative and obligate strategies can co-exist within populations of migratory animals.

Oosorption and migratory strategy of the milkweed bug, Oncopeltus fasciatus

Migration evolves as a response to seasonally unfavourable environments but plasticity in reproductive physiology is another avenue by which insects can respond to resource-poor conditions. We investigated the relationship between individual variation in migratory propensity and the level of response to poor conditions modulated by the female reproductive physiology. We tested the hypothesis that, compared to migrants, residential behaviour is associated with a higher degree of phenotypic plasticity in oosorption, an adaptive physiological mechanism that allows females to recoup resources from undeveloped oocytes. Reallocation from reproduction to survival would allow females to skip migration and to cope with unfavourable environments. If this plasticity is evolved, we further predicted it would vary between as well as within populations. We examined variation associated with migratory behaviour in females from four populations of the milkweed bug, Oncopeltus fasciatus, using a behavioural assay to categorize females as either migrant or resident and observing the differences in oosorption between these groups. As expected, food availability, source population and wing length influenced the propensity for migratory flight, and food availability influenced levels of oosorption. We also found support for our key prediction that resident females are characterized by higher levels of ovarian oosorption than migrant females. Our study provides support for a physiological difference between migrant and resident females and suggests the presence of both physiological and behavioural tactics that interact with the potential for migration to provide adaptation to seasonally challenging environments.

Variation in candidate genes CLOCK and ADCYAP1 does not consistently predict differences in migratory behavior in the songbird genus Junco

Recent studies exploring the molecular genetic basis for migratory variation in animals have identified polymorphisms in two genes ( CLOCK and ADCYAP1) that are linked to circadian rhythms and correlate with migratory propensity and phenology among individuals and populations. Results from these initial studies are mixed, however, and additional data are needed to assess the generality and diversity of the molecular mechanisms that regulate the biology of migration. We sequenced CLOCK and ADCYAP1 in 15 populations across the two species of the avian genus Junco, a North American lineage in which multiple recently diverged subspecies and populations range from sedentary to long-distance migrants. We found no consistent associations between allele length and migratory status across the genus for either CLOCK or ADCYAP1. However, within two subspecies groups, populations that migrate longer distances have longer CLOCK alleles on average. Additionally, there was a positive relationship between ADCYAP1 allele length and migratory restlessness (zugunruhe) among individuals within one of two captive populations studied—a result similar to those reported previously within captive blackcaps ( Sylvia atricapilla). We conclude that, while both ADCYAP1 and CLOCK may correlate with migratory propensity within or among certain populations or species, previously identified relationships between migratory behavior and sequence variants cannot be easily generalized across taxa.

Abstract 2137: Using Rac1 isogenic cells to model tumor metastasis

Abstract The Rho family of GTPases regulate a wide range of normal cellular functions including cell growth and cytoskeleton dynamics, but it is becoming increasingly apparent that when deregulated, proteins such as Rac1 contribute to tumorigensis, tumour invasion and metastasis. Overexpression of Cdc42 and Rac1 have been reported in human breast cancer, and coincide with breast cancer progression, metastasis and resistance to chemotherapy. The aim of this study was to generate a model system to investigate how Rac1 activation affects the migratory propensity of human breast epithelial cells. We utilised X-MAN isogenic cells derived from MCF10A mammary epithelial cells which harbour a single Q61L Rac1 mutation introduced by AAV-mediated homologous recombination, paired with a parental cell line expressing the wildtype allele. This system offers several advantages over conventional methods; protein expression is driven from endogenous promoters, thereby eliminating the caveats associated with transfection-based approaches. Using the X-MAN isogenic cells we showed that introduction of the Rac1Q61L mutation results in a profound effect on cell morphology. The most striking phenotype was the appearance of large intracellular vacuoles, but immunofluorescence studies also revealed cytoskeletal abnormalities with Rac1Q61L cells showing evidence of microtubule disorganisation and accumulation of newly polymerised actin fibers. These observations, in conjunction with previous reports that activated Rac is associated with cell migration, prompted us to address whether these cells may also have a migratory phenotype. Using Transwell and scratch assays, we confirmed that Rac1Q61L cells are more motile than their parental counterparts, and this correlated with increased adhesive properties. Pathway analysis revealed Rac1Q61L cells express higher basal levels of activated MEK and ERK, both of which have been implicated in the migration of numerous cell types. In conclusion, we have generated a pair of isogenic cell lines to demonstrate how constitutive Rac1 activation results in cytoskeletal changes and increased motility. Our data highlights the advantages of being able to study clinically-relevant pathways in a phenotypically-relevant assay, and how this platform could be exploited to profile molecularly targeted agents aimed at reducing tumour invasion and metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2137. doi:1538-7445.AM2012-2137

Network analysis and proteomic identification of vimentin as a key regulator associated with invasion and metastasis in human hepatocellular carcinoma cells

Poor prognoses have long been associated with the high relapse and metastasis of human hepatocellular carcinoma (HCC). To achieve long-term survival, it is necessary to identify new HCC biomarkers and investigate their roles in cell mobility and invasiveness. Of note, overexpression of vimentin (Vim) was significantly correlated with tumor nuclear grade (p=0.01) and the invasive potential, indicating that Vim may be a promising candidate in regulating HCC metastasis. RNA interference-mediated silencing of Vim (siVim) suppressed the invasive and migratory propensity, and matrix metalloproteinase (MMP)-9 activity, and elicited morphological changes in poorly differentiated SK-Hep-1 cells. Moreover, we performed a comprehensive proteomic analysis to survey global protein changes mediated by siVim in SK-Hep-1 cells. Significant changes in cytoskeleton protein but not messenger RNA levels encoding these targeted proteins were observed. All of the data in the current study and a network analysis implied that abolition of Vim may disturb the expression and stability of various cytoskeletal proteins through promoting the ubiquitin system, resulting in impaired cell adhesion and motility. Collectively, an integrated approach represents a modality to explore novel relationships in a proteome complex and highlights the functional roles of Vim in HCC metastasis. This article is part of a Special Issue entitled: Translational Proteomics.

Directions in modelling partial migration: how adaptation can cause a population decline and why the rules of territory acquisition matter

Modelling of partial migration in birds has progressed from simple graphical representations to sophisticated analyses that use evolutionary invasion analysis to determine how the success of the two strategies (stay year round on the breeding grounds, or migrate) can become frequency dependent. Here I build two models to relax two assumptions commonly made in models and often violated in nature: that individuals do not vary in any trait other than their migratory propensity, and that the prior residence effect (which grants priority access of good habitats to non‐migrants) operates at maximum strength. The same framework can incorporate and merge aspects of various hypotheses proposed to explain partial migration (dominance, body size, arrival timing, and limited foraging opportunities), and shows that either small (subdominant) or large (dominant) individuals may emerge as the more likely migrants; the latter case occurs when it is easy for socially dominant migrants to win back prime breeding locations upon their arrival. The dynamics of territory acquisition is shown to be an important and understudied topic, as variations in the relative importance of prior residency versus resource holding power can shift a population from complete migration to complete year‐round residency. These models also highlight exceptions to a tacit assumption in discussions of evolution of migration under climate change, which is that populations can decline if genetic adaptation or phenotypic plasticity do not occur fast enough. Competition can also yield the opposite pattern where adaptation itself leads to a population decline.

Reprogramming Urokinase into an Antibody-Recruiting Anticancer Agent

Synthetic compounds for controlling or creating human immunity have the potential to revolutionize disease treatment. Motivated by challenges in this arena, we report herein a strategy to target metastatic cancer cells for immune-mediated destruction by targeting the urokinase-type plasminogen activator receptor (uPAR). Urokinase-type plasminogen activator (uPA) and uPAR are overexpressed on the surfaces of a wide range of invasive cancer cells and are believed to contribute substantially to the migratory propensities of these cells. The key component of our approach is an antibody-recruiting molecule that targets the urokinase receptor (ARM-U). This bifunctional construct is formed by selectively, covalently attaching an antibody-binding small molecule to the active site of the urokinase enzyme. We demonstrate that ARM-U is capable of directing antibodies to the surfaces of target cancer cells and mediating both antibody-dependent cellular phagocytosis (ADCP) and antibody-dependent cellular cytotoxicity (ADCC) against multiple human cancer cell lines. We believe that the reported strategy has the potential to inform novel treatment options for a variety of deadly, invasive cancers.

To boldly go: individual differences in boldness influence migratory tendency

Partial migration, whereby only a fraction of the population migrates, is thought to be the most common type of migration in the animal kingdom, and can have important ecological and evolutionary consequences. Despite this, the factors that influence which individuals migrate and which remain resident are poorly understood. Recent work has shown that consistent individual differences in personality traits in animals can be ecologically important, but field studies integrating personality traits with migratory behaviour are extremely rare. In this study, we investigate the influence of individual boldness, an important personality trait, upon the migratory propensity of roach, a freshwater fish, over two consecutive migration seasons. We assay and individually tag 460 roach and show that boldness influences migratory propensity, with bold individuals being more likely to migrate than shy fish. Our data suggest that an extremely widespread personality trait in animals can have significant ecological consequences via influencing individual-level migratory behaviour.

Abstract 1516: Estrogen regulated TME factors are novel modulators of neovasculogenesis and EMT in breast cancer

Abstract The tumor microenvironment plays host to multiple cell types that aid in tumor metastasis and recent work has begun to focus on the impact of non-malignant cells in breast cancer progression. Tumor metastasis relies on neovasculogenesis, aided by bone marrow-derived endothelial progenitor cells (BM-EPCs), which is critical for invasive tumor growth as well as an epithelial to mesenchymal transition (EMT) by malignant cells, allowing them to break from the primary tumor site and migrate to secondary foci. The modulators of tumor induced neovasculogenesis as well as EMT need elucidation. Previously we reported that estrogen significantly enhanced BM-EPC migration to mouse mammary tumor sites in vivo, resulting in an increase in neovasculogenesis and induction of proangiogenic and prometastatic proteins including vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). Using in vitro assays, we observed that estrogen leads to stabilization of the transcription factor hypoxia inducible factor 1 α (HIF-1α), a key regulator of hypoxia signaling, in the mouse mammary tumor cell line TG1-1. We observed that estrogen signaling via HIF-1α leads to an increase in VEGF, and conditioned media from TG1-1 cells treated with estrogen leads to a significant increase in human umbilical vein endothelial cell (HUVEC) migration in vitro, an effect abrogated by the anti-estrogen Fulvestrant as well as 3-(5’-hydroxymethyl-2’-furyl)-1-benzylindazole (YC1) a specific HIF-1α inhibitor. While tumor growth induces neovasculogenesis via endothelial cell recruitment, the inflammatory environment created stimulates infiltration of tumor associated macrophages, or TAMs. We further observed that conditioned media from the mouse macrophage cell line RAW264.7 induced EMT in TG1-1 cells, leading to an increase in both the EMT transcription factor TWIST and TG1-1 cell migration. Thus, an inflammatory environment leads to macrophage dependent secretion of pro-metastatic factors, resulting in breast tumor cell EMT and migratory propensity. We conclude that estrogen modulated secreted factors in different cell types influence the tumor microenvironment and have functional consequences on tumor cell growth and metastasis and may provide targets for clinical therapeutic intervention. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1516. doi:10.1158/1538-7445.AM2011-1516

Stromal Expression of β-Arrestin-1 Predicts Clinical Outcome and Tamoxifen Response in Breast Cancer

The G-protein coupled receptor associated protein β-arrestin-1 is crucial for the regulation of numerous biological processes involved in cancer progression, such as intracellular signaling and cell motility. The encoding gene ARRB1 is harbored in the same chromosomal region as the CCND1 gene (11q13). Amplification of CCND1, frequently encountered in breast cancer, often involves coamplification of additional oncogenes, as well as deletion of distal 11q genes. We investigated the clinical relevance of β-arrestin-1 in breast cancer and elucidated a potential link between β-arrestin-1 expression and CCND1 amplification. β-Arrestin-1 protein expression was evaluated in two breast cancer patient cohorts, comprising 179 patients (cohort I) and 500 patients randomized to either tamoxifen or no adjuvant treatment (cohort II). Additionally, migration after β-arrestin-1 overexpression or silencing was monitored in two breast cancer cell lines. Overexpression of β-arrestin-1 reduced the migratory propensity of both cell lines, whereas silencing increased migration. In cohort I, high expression of stromal β-arrestin-1 was linked to reduced patient survival, whereas in cohort II both high and absent stromal expression predicted a poor clinical outcome. Patients exhibiting low or moderate levels of stromal β-arrestin-1 did not benefit from tamoxifen, in contrast to patients exhibiting absent or high expression. Furthermore, CCND1 amplification was inversely correlated with tumor cell expression of β-arrestin-1, indicating ARRB1 gene deletion in CCND1-amplified breast cancers.