The relations between growth mindset, motivational beliefs, and career interest in math intensive fields in informal STEM youth programs

Past research has shown that growth mindset and motivational beliefs have an important role in math and science career interest in adolescence. Drawing on situated expectancy-value theory (SEVT), this study extends these findings by investigating the role of parental motivational beliefs (e.g., expectancy beliefs, utility values) and parent growth mindset in math on adolescent career interest in math-intensive fields (e.g., mathematics, computer science, statistics, and engineering; MCSE) through adolescent motivational beliefs in math. Structural equation modeling was used to test the hypothesized model using data from 290 adolescents (201 girls, 69.3%; Mage = 15.20), who participate in informal STEM (science, technology, engineering, mathematics) youth programs, and their parents (162 parents, 87.7% female) in the United Kingdom and the United States. As hypothesized, adolescent expectancy beliefs, utility values, and growth mindset in math had a significant direct effect on MCSE career interest. Further, there was a significant indirect effect of parental expectancy beliefs in math on MCSE career interest through adolescents' expectancy beliefs. Similarly, there was a significant indirect effect from parental utility values in math to MCSE career interest through adolescents' utility values. The findings suggest that parents' math motivational beliefs play a critical role in adolescent math motivational beliefs and their career interest in math-intensive fields.

Developmental Trajectories of Adolescents' Math Motivation: The Role of Mindset and Perceptions of Informal STEM Learning Site Inclusivity

Motivation is a key factor in engagement, achievement, and career choices in science, technology, engineering, and mathematics (STEM). While existing research has focused on student motivation toward math in formal school programs, new work is needed that focuses on motivation for those involved in informal STEM programs. Specifically, the role of math mindset and perceived inclusivity of informal STEM sites (to those of varying gender and ethnic backgrounds) on longitudinal trajectories of adolescents' math motivation has not been explored. This study investigates longitudinal changes in math expectancy, interest, and utility values and the effects of math fixed mindset, math growth mindset, and perceptions of the inclusivity of informal STEM learning sites on these changes for adolescents participating in STEM programs at these informal sites in the United Kingdom and the United States (n = 249, MT1age = 15.2, SD = 1.59). Three latent growth curve models were tested. The data suggest that math expectancy, interest, and utility values declined over three years. Growth mindset positively predicted changes in utility, while fixed mindset negatively predicted changes in utility. Inclusivity positively influenced the initial levels of utility. Girls reported lower initial expectancy than boys. Age influenced both the initial levels and rate of change for expectancy. Older adolescents had lower levels of expectancy compared to their younger counterparts; however, they had a less steep decline in expectancy over three years. These findings suggest that designing inclusive learning environments and promoting growth mindset may encourage math motivation.

Children's and adolescents' evaluations of wealth-related STEM inequality

The fields of science, technology, engineering, and mathematics (STEM) are rife with inequalities and under-representation that have their roots in childhood. While researchers have focused on gender and race/ethnicity as two key dimensions of inequality, less attention has been paid to wealth. To this end, and drawing from the Social Reasoning Development approach, we examined children's and adolescents' perceptions of STEM ability and access to opportunities as a function of wealth, as well as their desire to rectify such inequalities. Participants (n = 234: early childhood, n = 70, mean age = 6.33, SD = .79; middle childhood, n = 92, mean age = 8.90, SD = .83 and early adolescence, n = 62, mean age = 12.00; SD = 1.16) in the U.K. (64% White British) and U.S. (40% White/European American) read about two characters, one high-wealth and one low-wealth. In early childhood, participants reported that the high-wealth character would have greater STEM ability and were just as likely to invite either character to take part in a STEM opportunity. By middle childhood, participants were more likely to report equal STEM abilities for both characters and to seek to rectify inequalities by inviting the low-wealth character to take part in a STEM opportunity. However, older participants reported that peers would still prefer to invite the high-wealth character. These findings also varied by ethnic group status, with minority status participants rectifying inequalities at a younger age than majority status participants. Together these findings document that children are aware of STEM inequalities based on wealth and, with age, will increasingly seek to rectify these inequalities.

Reciprocal Associations Between Science Efficacy, STEM Identity and Scientist Career Interest Among Adolescent Girls within the Context of Informal Science Learning

Limited research has explored the longitudinal pathway to youth career interests via identity and efficacy together. This study examined the longitudinal associations between science efficacy, STEM (science, technology, engineering and math) identity, and scientist career interest among girls who are historically considered as an underrepresented group among scientists. The sample included 308 girls (M age = 15.22, SD age = 1.66; 42.8% White) from six STEM youth programs, each at a different informal science learning site within the U.K. and the U.S. Longitudinal structural equation modelling demonstrated that science efficacy consistently predicted STEM identity and scientist career interest, and similarly, STEM identity consistently predicted science efficacy over a two-year period. Scientist career interest at 12 months predicted science efficacy at 24 months. The coefficients of efficacy predicting STEM identity and scientist career interest were significantly larger compared to STEM identity and scientist career interest in predicting science efficacy from 12 months to 24 months. Further mediation analysis supported a significant pathway from STEM identity at 3 months to scientist career interest at 24 months via 12-month science efficacy. The findings highlight that science efficacy and STEM identity for girls relate to their scientist career interest and these longitudinal associations are reciprocal. This study suggests that science efficacy and STEM identity mutually influence each other, and enhancing science efficacy and STEM identity is key to promoting adolescents' interest in being a scientist.

Interferon epsilon and ovarian cancer

Most biologists know of the interferons IFNα, IFNβ, and IFNγ and their roles in immunity and infection, but they may not have heard of IFNε. A recent study in Nature suggests that IFNε can act as a tumor suppressor in serous ovarian cancers.

Investigating the impact of London's ultra low emission zone on children's health: children's health in London and Luton (CHILL) protocol for a prospective parallel cohort study

BACKGROUND

Air pollution harms health across the life course. Children are at particular risk of adverse effects during development, which may impact on health in later life. Interventions that improve air quality are urgently needed both to improve public health now, and prevent longer-term increased vulnerability to chronic disease. Low Emission Zones are a public health policy intervention aimed at reducing traffic-derived contributions to urban air pollution, but evidence that they deliver health benefits is lacking. We describe a natural experiment study (CHILL: Children's Health in London and Luton) to evaluate the impacts of the introduction of London's Ultra Low Emission Zone (ULEZ) on children's health.

METHODS

CHILL is a prospective two-arm parallel longitudinal cohort study recruiting children at age 6-9 years from primary schools in Central London (the focus of the first phase of the ULEZ) and Luton (a comparator site), with the primary outcome being the impact of changes in annual air pollutant exposures (nitrogen oxides [NOx], nitrogen dioxide [NO2], particulate matter with a diameter of less than 2.5micrograms [PM2.5], and less than 10 micrograms [PM10]) across the two sites on lung function growth, measured as post-bronchodilator forced expiratory volume in one second (FEV1) over five years. Secondary outcomes include physical activity, cognitive development, mental health, quality of life, health inequalities, and a range of respiratory and health economic data.

DISCUSSION

CHILL's prospective parallel cohort design will enable robust conclusions to be drawn on the effectiveness of the ULEZ at improving air quality and delivering improvements in children's respiratory health. With increasing proportions of the world's population now living in large urban areas exceeding World Health Organisation air pollution limit guidelines, our study findings will have important implications for the design and implementation of Low Emission and Clean Air Zones in the UK, and worldwide.

CLINICALTRIALS

GOV: NCT04695093 (05/01/2021).

Preparing the Next Generation for STEM: Adolescent Profiles Encompassing Math and Science Motivation and Interpersonal Skills and Their Associations With Identity and Belonging

Science, technology, engineering, and math (STEM) workers need both motivation and interpersonal skills in STEM disciplines. The aims of the study were to identify clusters of adolescents who vary in math and science motivation and interpersonal skills and to explore what factors are related to membership in a high math and science motivation and interpersonal skills cluster. Participants included 467 adolescents (312 female; Mage = 15.12 to SD = 1.71 year) recruited from out-of-school STEM programs in the US and UK. Findings from latent class analyses revealed four clusters, including a "High Math and Science Motivation and Interpersonal Skills" group, as well as groups that exhibited lower levels of either motivation or interpersonal skills. STEM program belonging, and STEM identity are related to membership in the high motivation and skills cluster. Findings provide insight into factors that may encourage motivation and interpersonal skills in adolescents, preparing them for STEM workforce entry.

Interest, Mindsets and Engagement: Longitudinal Relations in Science Orientations for Adolescents in Informal Science Programs

Little is known about the factors that influence engagement for adolescents participating in informal youth science programs. This study examined longitudinal reciprocal associations between adolescents' science engagement, interest, and growth mindset. Participants were adolescents (M_age = 15.06, SD = 1.82 years, 66.8% female) from the UK (n = 168) and the US (n = 299). A cross lagged path analysis indicated that participants' science growth mindset at baseline was positively related to interest, and engagement at year 1, and science interest at year 1 was positively related to growth mindset at year 2. Additionally, girls had lower science growth mindsets than boys. This evidence suggests that informal programs may encourage positive STEM trajectories by fostering engagement, growth mindset and interest.

Semi-supervised analysis of myeloid and T cell behavior in ex vivo ovarian tumor slices reveals changes in cell motility after treatments

Studies of the high-grade serous ovarian cancer (HGSOC) tumor microenvironment, the most lethal gynecological cancer, aim to enhance the efficiency of established therapies. Cell motility is an important process of anti-tumor response. Using ex vivo human and mouse HGSOC tumor slices combined with time-lapse imaging, we assessed the motility of CD8+ T and myeloid cells. We developed a semi-supervised analysis of cell movements, identifying four cell behaviors: migrating, long migrating, static, and wobbling. Tumor slices were maintained 24h ex vivo, retaining viability and cell movements. Ex vivo treatments with lipopolysaccharide altered CD8+ T and myeloid cell behavior. In vivo chemotherapy reduced ex vivo cell movements in human and mouse tumors and differentially affected CD8+ T and myeloid cells in chemo-sensitive and chemo-resistant mouse models. Ex vivo tumor slices can extend in vivo mouse studies to human, providing a stepping stone to translate mouse cancer studies to clinical trials.

The impact of pericytes on the stability of microvascular networks in response to nanoparticles

Recapitulating the normal physiology of the microvasculature is pivotal in the development of more complex in-vitro models and organ-on-chip designs. Pericytes are an important component of the vasculature, promoting vessel stability, inhibiting vascular permeability and maintaining the vascular hierarchical architecture. The use of such co-culture for the testing of therapeutics and nanoparticle safety is increasingly considered for the validation of therapeutic strategies. This report presents the use of a microfluidic model for such applications. Interactions between endothelial cells and pericytes are first explored. We identify basal conditions required to form stable and reproducible endothelial networks. We then investigate interactions between endothelial cells and pericytes via direct co-culture. In our system, pericytes prevented vessel hyperplasia and maintained vessel length in prolonged culture (> 10 days). In addition, these vessels displayed barrier function and expression of junction markers associated with vessel maturation, including VE-cadherin, β-catenin and ZO-1. Furthermore, pericytes maintained vessel integrity following stress (nutrient starvation) and prevented vessel regression, in contrast to the striking dissociation of networks in endothelial monocultures. This response was also observed when endothelial/pericyte co-cultures were exposed to high concentrations of moderately toxic cationic nanoparticles used for gene delivery. This study highlights the importance of pericytes in protecting vascular networks from stress and external agents and their importance to the design of advanced in-vitro models, including for the testing of nanotoxicity, to better recapitulate physiological response and avoid false positives.

Abstract 5913: Semi-supervised analysis of myeloid and T cell behavior in ex vivo ovarian tumor slices reveals changes in cell motility after treatments

Cell motility is an important component of anti-tumor responses, allowing immune cells like myeloid and cytotoxic T cells to infiltrate tumors. Using ex vivo human and mouse high-grade serous ovarian cancer (HGSOC) tumor slices combined with time-lapse imaging, we monitored the movement of CD8+ T and myeloid cells in live tumors, in real-time. To analyze the recordings and characterize immune cell movements, we developed a semi-supervised analysis, identifying four types of cell behavior: migrating, long migrating, static and wobbling. Tumor slices were maintained 24h ex vivo, retaining viability and cell movements. We show that ex vivo treatments with LPS altered CD8+ T and myeloid cell behavior. In vivo chemotherapy reduced ex vivo cell movements in human and mouse tumors, and differentially affected CD8+ T and myeloid cells in 60577 and HGS2 murine tumors, respectively chemo-sensitive and chemo-resistant mouse models, suggesting those cell types have different roles in the response to chemotherapy. Ex vivo tumor slices can extend in vivo mouse work to human, providing a stepping stone to translate mouse cancer studies to clinical trials.

Citation Format: Florian Laforets, Panoraia Kotantaki, Beatrice Malacrida, Samar Elorbany, Ranjit Manchanda, Emmanuel Donnadieu, Frances Balkwill. Semi-supervised analysis of myeloid and T cell behavior in ex vivo ovarian tumor slices reveals changes in cell motility after treatments [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5913.

Abstract 4576: 3D in vitro models uncover malignant cell intrinsic and extrinsic mechanisms of CAR-T cell resistance in high grade serous ovarian cancer

Chimeric antigen receptor (CAR)-T cell therapies have promising outcomes in hematologic malignancies but limited activity in solid tumors. We used 3-dimentional (3D) in vitro human cell models of increasing complexity to investigate resistance to CAR-T cell therapy in high grade serous ovarian cancer (HGSOC), a disease with poor response to immunotherapy. We identified mucin-1 (MUC1) and TnMUC1 as target antigens in HGSOC omental metastasis and the HGSOC cell lines, OvCAR3 and G164. We then generated CAR-T cells against these targets and tested them in spheroids, collagen gels and microfluidic models. In spheroids, OvCAR3 cells were killed by CAR-T cells whereas, G164 cells were resistant to CAR-T cell cytotoxicity. RNA sequencing suggested that the impaired apoptotic signaling in G164 cells caused malignant cell-intrinsic resistance to CAR-T cell cytotoxicity. Treating G164 spheroids with birinapant, an antagonist of cellular inhibitor of apoptosis protein, induced CAR-T cell cytotoxicity. Moreover, when resistant cells were co-cultured as spheroids with primary omental fibroblasts from ovarian cancer patients, CAR-T cells were activated and cytotoxic. G164 spheroids cultured in fibroblast-conditioned medium also induced CAR-T cell cytotoxicity due to C-C motif chemokine ligand 2 (CCL2) produced by fibroblasts. CCL2 activated CCR2/4+ CAR-T cells to induce cytotoxicity in an antigen-dependent manner. We then investigated CAR-T cell migration and cytotoxicity in malignant cell/fibroblast co-culture collagen gels. CAR-T cell migrated into OvCAR3 gels and were cytotoxic against the malignant cells. However, a dense extracellular matrix (ECM) produced primarily by fibroblasts prevented CAR-T cell migration and cytotoxicity in G164 gels. Treating G164 gels with transforming growth factor beta (TGFβ) receptor inhibitor SB431542 reduced ECM content and altered ECM structure, thus stimulating CAR-T cell penetration and restoring cytotoxicity against G164 cells. We also developed an ovarian cancer-on-a-chip model which involved culturing cell-seeded collagen gels in vascularized tri-channel microfluidic devices. CAR-T cells successfully penetrated and killed malignant cells in co-culture collagen gels when delivered through vascularized microfluidic devices. To our knowledge, this is the first report to use microfluidic tumor models to successfully deliver CAR-T cells. Using these different human 3D in vitro models, we uncovered malignant cell-intrinsic factors and novel mechanisms involving fibroblasts which may influence CAR-T cell activity. Complex human cell models may accelerate preclinical research into CAR-T cell therapies in solid tumors.

Citation Format: Joash Dominic Joy, Beatrice Malacrida, Florian Laforêts, Panoraia Kotantaki, Eleni Maniati, Sarah Hopkins, Ianire Garrobo-Calleja, Julien Gautrot, Frances Balkwill. 3D in vitro models uncover malignant cell intrinsic and extrinsic mechanisms of CAR-T cell resistance in high grade serous ovarian cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4576.

A role for macrophages under cytokine control in mediating resistance to ADI-PEG20 (pegargiminase) in ASS1-deficient mesothelioma

BACKGROUND

Pegylated arginine deiminase (ADI-PEG20; pegargiminase) depletes arginine and improves survival outcomes for patients with argininosuccinate synthetase 1 (ASS1)-deficient malignant pleural mesothelioma (MPM). Optimisation of ADI-PEG20-based therapy will require a deeper understanding of resistance mechanisms, including those mediated by the tumor microenvironment. Here, we sought to reverse translate increased tumoral macrophage infiltration in patients with ASS1-deficient MPM relapsing on pegargiminase therapy.

METHODS

Macrophage-MPM tumor cell line (2591, MSTO, JU77) co-cultures treated with ADI-PEG20 were analyzed by flow cytometry. Microarray experiments of gene expression profiling were performed in ADI-PEG20-treated MPM tumor cells, and macrophage-relevant genetic "hits" were validated by qPCR, ELISA, and LC/MS. Cytokine and argininosuccinate analyses were performed using plasma from pegargiminase-treated patients with MPM.

RESULTS

We identified that ASS1-expressing macrophages promoted viability of ADI-PEG20-treated ASS1-negative MPM cell lines. Microarray gene expression data revealed a dominant CXCR2-dependent chemotactic signature and co-expression of VEGF-A and IL-1α in ADI-PEG20-treated MPM cell lines. We confirmed that ASS1 in macrophages was IL-1α-inducible and that the argininosuccinate concentration doubled in the cell supernatant sufficient to restore MPM cell viability under co-culture conditions with ADI-PEG20. For further validation, we detected elevated plasma VEGF-A and CXCR2-dependent cytokines, and increased argininosuccinate in patients with MPM progressing on ADI-PEG20. Finally, liposomal clodronate depleted ADI-PEG20-driven macrophage infiltration and suppressed growth significantly in the MSTO xenograft murine model.

CONCLUSIONS

Collectively, our data indicate that ADI-PEG20-inducible cytokines orchestrate argininosuccinate fuelling of ASS1-deficient mesothelioma by macrophages. This novel stromal-mediated resistance pathway may be leveraged to optimize arginine deprivation therapy for mesothelioma and related arginine-dependent cancers.

Promoting Diverse Youth's Career Development through Informal Science Learning: The Role of Inclusivity and Belonging

Little research has examined the associations between perceived inclusivity within informal science learning sites, youth program belonging and perceptions of program career preparation. This study explored relations between these factors at three timepoints (T1 = start of program, T2 = 3 months and T3 = 12 months after start). Participants were a diverse sample of 209 adolescents participating in STEM youth programs within informal science learning sites situated in the United States and United Kingdom (70% females: M _age = 15.27, SD _age = 1.60), with 53.1% British and 64.1% non-White. Path analysis revealed that only perceptions of inclusivity for own social identity group (i.e., gender, ethnicity) at T1 were associated with T2 STEM youth program belonging. There was a significant indirect effect of T1 perceptions of inclusivity for one's own social identity groups on T3 perceptions of program career preparation via T2 program belonging. This study highlights that, over time, perceptions of inclusivity around youth's own social identity groups (i.e., gender and ethnicity/culture) are related to a sense of youth program belonging, which in turn is later associated with perceptions of program career preparation.

Abstract 693: TGFβ-mediated targeting of the extracellular matrix enhances the migration and cytotoxicity of CAR-T cells in 3D models of ovarian cancer

We have assessed the utility of 3-dimensional (3D) in vitro human cell models to understand barriers to chimeric antigen receptor (CAR)-T cell activity in high-grade serous ovarian cancer, (HGSOC) a disease with a poor response to immunotherapy. We defined mucin-1 (MUC1) as a potential target in HGSOC biopsies and the HGSOC cell lines, OvCAR3 and G164. We then generated CAR-T cells against MUC1 and tested them in spheroid and collagen gel cultures. In spheroids, although CAR-T cells killed OvCAR3 cells, G164 cells failed to induce CAR-T cell activation or cytotoxicity. However, when we added primary omental fibroblasts from ovarian cancer patients to G164 spheroids, CAR-T cells were activated and cytotoxic. Fibroblast conditioned medium also activated CAR-T cells to kill G164 cells in spheroids and this was due to their production of C-C motif chemokine ligand 2 (CCL2). Further experiments revealed that CCL2 produced by fibroblast stimulated CCR2/4 positive CAR-T cells to a higher state of activation, which enhanced the cytotoxicity of CAR-T cells against G164 cells. We then investigated CAR-T cell activity in co-cultures of OvCAR3 or G164 cells and primary fibroblasts embedded in collagen. CAR-T cells migrated into OvCAR3 gels and killed the malignant cells during a three-day period. However, CAR-T cells failed to migrate into gels with G164 cells and there was no malignant cell killing. Gels containing G164 cells had denser extracellular matrix (ECM) than OvCAR3 gels, as measured by staining for collagens and fibronectin. Previously, we showed that transforming growth factor-beta (TGFβ) secreted by HGSOC cells acted on fibroblasts to induce the production of ECM in collagen gels.1 Treating G164 gels with the TGFβ receptor inhibitor SB431542 reduced ECM density, stimulated CAR-T cell migration and restored CAR-T cell cytotoxicity against G164 cells. Using these different human 3D models we have demonstrated that malignant cell intrinsic factors can cause resistance to CAR-T cells. Sensitivity to CAR-T cell killing can be modulated both positively and negatively by fibroblasts. Targeting ECM along with CAR-T cell therapy might improve the efficiency of CAR-T cells in solid tumors.

1Delaine-Smith et al, iScience, 2021

Citation Format: Joash Dominic Joy, Beatrice Malacrida, Florian Laforêts, Panoraia Kotantaki, Eleni Maniati, Sarah Hopkins, Ianire Calleja, Sara Brett, Takis Athanasopoulos, Sadfer Ali, Peter Emery-Billcliff, Ida Ricciardelli, Charlotte Kay, Jayne Colebrook, Magda Ali, Katherine Strong, Frances Balkwill. TGFβ-mediated targeting of the extracellular matrix enhances the migration and cytotoxicity of CAR-T cells in 3D models of ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 693.

Loss of mTORC2-induced metabolic reprogramming in monocytes uncouples migration and maturation from production of proinflammatory mediators

Monocyte migration to the sites of inflammation and maturation into macrophages are key steps for their immune effector function. Here, we show that mechanistic target of rapamycin complex 2 (mTORC2)-dependent Akt activation is instrumental for metabolic reprogramming at the early stages of macrophage-mediated immunity. Despite an increased production of proinflammatory mediators, monocytes lacking expression of the mTORC2 component Rictor fail to efficiently migrate to inflammatory sites and fully mature into macrophages, resulting in reduced inflammatory responses in vivo. The mTORC2-dependent phosphorylation of Akt is instrumental for the enhancement of glycolysis and mitochondrial respiration, required to sustain monocyte maturation and motility. These observations are discussed in the context of therapeutic strategies aimed at selective inhibition of mTORC2 activity.

Abstract 1094: Differential responses and mechanisms of resistance to cediranib in high grade serous ovarian cancer mouse models

The aim of this study was to investigate the effects of cediranib and understand mechanisms of resistance in syngeneic mouse models of high grade serious ovarian cancer (HGSOC). Cediranib, a VEGFR targeting agent, improves progression free survival in ovarian cancer patients but the benefits can be short lived. We recently conducted an extensive analysis of the tumor microenvironment, TME, of orthotopic syngeneic HGSOC models, including two cell lines, 30200 and 60577, which were P53 -/-, Brca1 -/- and had Rb inactivation (Maniati et al, Cell Reports 2020). In spite of the same genetic mutations, the transcriptional profile of peritoneal tumors from these two models had some distinct differences including regulation of genes in the IL-6 signaling pathway, with higher levels in 30200 compared to 60577.

Four- 5 weeks cediranib treatment of mice bearing 30200 or 60577 intraperitoneal tumors significantly reduced tumor burden with inhibition of vessel density and modulation of immune cell profiles in the TME. However, there was little impact on overall survival of mice even with continued treatment, but mechanisms of resistance appeared to be different. In 30200-bearing mice treated with cediranib, there was an increase in peritoneal metastasis and pSTAT3 signaling in the TME. In 60577-bearing mice, there was still a decrease in vessel density and pSTAT3 signaling at survival endpoint with distinct changes to immune infiltrate, including a decrease in CD8 T cells, an increase in alternatively activated macrophages and upregulation of checkpoint molecules PD-1/PDL-1.

In view of these results we combined cediranib treatment with anti-IL-6 antibodies in the 30200 model and with anti-PD-1 antibodies in the 60577 model to see if this would overcome resistance. These combination treatments significantly increased mouse survival compared to the monotherapies with no increase in peritoneal metastases.

To further understand the relevance of the pre-treatment transcriptional profile in dictating response to cediranib treatment, we studied the effects of cediranib treatment in another HGSOC mouse model, HGS2. This model shared similar levels of IL-6 pathway expression to 30200 tumors and showed no survival benefit to cediranib treatment and, again, increased peritoneal metastasis. The combination of anti-IL-6 and cediranib significantly improved HGS2 mouse survival.

As the transcriptomes of these mouse model had significant correlations with human HGSOC tumors, we looked for these pathway correlations with angiogenic signatures in human patient dataset. Analysis of the ICGC dataset revealed strong correlations of angiogenesis signature with IL-6 and PD-1 pathways suggesting biomarkers for treatments to combine with VEGF inhibitors in ovarian cancer.

Citation Format: Ganga Gopinathan, Eleni Maniati, Chiara Berlato, Anissa Lakhani, Colin Pergum, Florian Laforets, Ludmila Szabova, Frances Balkwill. Differential responses and mechanisms of resistance to cediranib in high grade serous ovarian cancer mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1094.

Targeting DNA Damage Response and Replication Stress in Pancreatic Cancer

BACKGROUND & AIMS

Continuing recalcitrance to therapy cements pancreatic cancer (PC) as the most lethal malignancy, which is set to become the second leading cause of cancer death in our society. The study aim was to investigate the association between DNA damage response (DDR), replication stress, and novel therapeutic response in PC to develop a biomarker-driven therapeutic strategy targeting DDR and replication stress in PC.

METHODS

We interrogated the transcriptome, genome, proteome, and functional characteristics of 61 novel PC patient-derived cell lines to define novel therapeutic strategies targeting DDR and replication stress. Validation was done in patient-derived xenografts and human PC organoids.

RESULTS

Patient-derived cell lines faithfully recapitulate the epithelial component of pancreatic tumors, including previously described molecular subtypes. Biomarkers of DDR deficiency, including a novel signature of homologous recombination deficiency, cosegregates with response to platinum (P < .001) and PARP inhibitor therapy (P < .001) in vitro and in vivo. We generated a novel signature of replication stress that predicts response to ATR (P < .018) and WEE1 inhibitor (P < .029) treatment in both cell lines and human PC organoids. Replication stress was enriched in the squamous subtype of PC (P < .001) but was not associated with DDR deficiency.

CONCLUSIONS

Replication stress and DDR deficiency are independent of each other, creating opportunities for therapy in DDR-proficient PC and after platinum therapy.

The Relations and Role of Social Competencies and Belonging with Math and Science Interest and Efficacy for Adolescents in Informal STEM Programs

Adolescence represents a developmental period of waning academic motivation, particularly in STEM domains. To combat this, better understanding the factors that might foster STEM motivation and interest is of importance. Social factors like social competencies and feelings of belonging become increasingly important in adolescence. The current study investigated structural relations between social competencies, feelings of belonging to an informal STEM learning program, math and science efficacy and interest in a sample of 268 adolescents (M_age = 15.25; 66.8% girls; 42.5% White British or European American, 25.7% South Asian British or Asian American, 15.7% Afro-Caribbean Black British or African American 5.6% Bi-racial, and 3.0% other). Adolescents were recruited from six different informal learning sites (e.g., science museums, zoos, or aquariums) in the United States (n = 147) and the United Kingdom (n = 121). The results revealed positive relations between social competencies and belonging, and between belonging and math and science efficacy and interest. Further, the results also indicated a positive indirect effect of social competencies on efficacy and interest, via belonging. These findings have implications for guiding informal STEM programming in ways that can enhance STEM motivation and interest.

Abstract 2217: Pegylated arginine deiminase sensitizes ASS1-negative and KRAS mutant non-small cell lung cancer to PD-1 blockade immunotherapy

Cancer cells display dysregulated amino acid synthesis underlying a key metabolic hallmark of tumorigenesis that may be exploited therapeutically via specific amino acid deprivation. In particular, we have identified that arginine deprivation therapy with pegylated arginine deiminase (ADI-PEG20), which hydrolyses exogenous arginine to citrulline and ammonia, is clinically active in argininosuccinate synthetase 1 (ASS1)-deficient non-small cell lung cancer (NSCLC) and enhances the activity of the antifolate pemetrexed. Moreover, prior studies have shown that ADI-PEG20 also induces tumoral PD-L1 expression and T cell infiltration and is additive with anti-PD-1/PD-L1 antibodies in melanoma and colorectal murine models. Here, we reverse translated ADI-PEG20 studies from patients with ASS1-deficient NSCLC, co-associating with KRAS mutations, to analyze the impact of arginine deprivation with PD1-based checkpoint immunotherapy using murine NSCLC cell line models. First, we showed the CMT64 cell line, which harbors the KRAS-G12V mutation and is resistant to anti-programmed death antibodies, was ASS1-negative and highly sensitive to ADI-PEG20 in vitro. Next, CMT64 tumor cells were implanted subcutaneously into the right flank of syngeneic immunocompetent C57BL/6 mice. Once tumors reached 80mm3 animals were randomly assigned to four groups and treated with vehicle control (PBS), ADI-PEG20 (12 mg/kg), anti-PD-1 antibodies (10 mg/kg) or the combination of ADI-PEG20 and PD-1 blockade. CMT64 tumors were refractory to PD-1 blockade while ADI-PEG20 monotherapy induced a modest tumor response, with a two-fold decrease in tumor growth compared to control (p=0.0058). In contrast, the combination of ADI-PEG20 and PD-1 blockade elicited robust anti-tumor activity with a five-fold reduction in CMT64 tumor volume compared to control (p=0.0003). Modulation of the tumor microenvironment was observed by fluorescence activated cell sorting. In particular, we noted that tumor-associated macrophages showed higher expression of MHCII upon ADI-PEG20 and anti-PD-1 therapy (p&lt;0.05). Lastly, mice treated with ADI-PEG20 and anti-PD-1 therapy, survived longer than either ADI-PEG20 or anti-PD-1 therapy alone or PBS. In summary, arginine deprivation with ADI-PEG20 and PD-1 blockade is synthetically lethal in aggressive murine NSCLC and warrants further clinical investigation. A new clinical trial evaluating ADI-PEG20 with atezolizumab in combination with pemetrexed and platinum is opening in 2020 in patients with aggressive ASS1-deficient and PD-1/PD-L1 refractory lung adenocarcinoma (ClinicalTrials.gov Identifier: NCT03498222).

Citation Format: Iuliia Pavlyk, Julie Foster, Katie Dexter, Jane Sobasowski, John Bomalarski, Chiara Berlato, Frances Balkwill, Peter W Szlosarek. Pegylated arginine deiminase sensitizes ASS1-negative and KRAS mutant non-small cell lung cancer to PD-1 blockade immunotherapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2217.

Interest and learning in informal science learning sites: Differences in experiences with different types of educators

This study explored topic interest, perceived learning and actual recall of exhibit content in 979 children and adolescents and 1,184 adults who visited informal science learning sites and interacted with an adult or youth educator or just the exhibit itself as part of family visits to the sites. Children in early childhood reported greater topic interest and perceived learning, but actually recalled less content, than participants in middle childhood or adolescence. Youth visitors reported greater interest after interacting with a youth educator than just the exhibit, and perceived that they learn more if they interact with an educator (youth or adult). Participants in middle childhood recall more when they encounter a youth educator. Adult visitors reported greater interest after interaction with a youth educator than with the exhibit alone or an adult educator. They also perceived that they learn more if they interact with an educator (youth or adult) than just the exhibit and perceived that they learned more if they interacted with a youth educator than an adult educator. Results highlight the benefits of educators in informal science learning sites and document the importance of attention to developmental needs.

Learning hand in hand: Engaging in research-practice partnerships to advance developmental science

Developmental science research often involves research questions developed by academic teams, which are tested within community or educational settings. In this piece, we outline the importance of research-practice partnerships, which involve both research and practice-based partners collaborating at each stage of the research process. We articulate challenges and benefits of these partnerships for developmental science research, identify relevant research frameworks that may inform these partnerships, and provide an example of an ongoing research-practice partnership.

Abstract IA15: Modeling the tumor microenvironment of high-grade serous ovarian cancer

Using biopsies of metastatic high-grade serous ovarian cancer (HGSOC) that ranged from minimal to extensive disease, we defined RNA and protein profiles that evolved with changes in cellularity, architecture, and tissue modulus. This gave new insights into host response to cancer as well as leukocyte, cytokine, and matrisome regulation in the tumor microenvironment (TME). Although we had studied a single metastatic site, we identified an extracellular matrix (ECM) gene expression signature, which we named the matrix index, that significantly associated with increased stiffness and disease score. High matrix index distinguished patients with a shorter overall survival in ovarian and twelve other primary cancers, suggesting a common matrix response to human cancer. We used this “deconstruction” analysis of a human TME to build 3D multicellular cultures of human HGSOC cells, primary omental fibroblasts, mesothelial cells, and adipocytes. These cultures reproduce the prognostic matrix index signature, as confirmed by RNAseq and immunofluorescence, of the human cancer biopsies. Using these 3D models, we can study regulation of the matrisome and cancer cell invasion. Similarly, we have conducted multilevel analysis of orthotopic mouse models of HGSOC metastases with relevant oncogenic mutations. This analysis identified significant correlations between the transcriptome, host cell infiltrates, immune response, matrisome, vasculature, and tissue modulus of mouse and human TMEs, with several stromal and malignant cell targets in common. However, each mouse model showed distinct differences and potential vulnerabilities that enabled us to predict response to chemotherapy and an anti-IL-6 antibody. The transcriptional profiles of the mouse tumors that differed in chemotherapy response were able to classify chemotherapy-sensitive and -refractory patient tumors. We believe that these 3D human and mouse models provide useful preclinical tools and may help identify subgroups of HGSOC patients most likely to respond to specific therapies.

Citation Format: Frances Balkwill. Modeling the tumor microenvironment of high-grade serous ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr IA15.

Pituitary tumour fibroblast-derived cytokines influence tumour aggressiveness

Tumour-associated fibroblasts (TAFs) are key elements of the tumour microenvironment, but their role in pituitary neuroendocrine tumours (PitNETs) has been little explored. We hypothesised that TAF-derived cytokines may play a role in tumour aggressiveness and that their release can be inhibited by somatostatin analogues. TAFs were isolated and cultured from 16 PitNETs (11 clinically non-functioning tumours and 5 somatotropinomas). The fibroblast secretome was assessed with a 42-plex cytokine array before and after multiligand somatostatin receptor agonist pasireotide treatment. Angiogenesis and epithelial-to-mesenchymal transition pathway assessment included CD31, E-cadherin and ZEB1 expression. GH3 cells treated with TAF- or skin fibroblast-conditioned medium were assessed for migration, invasion and cell morphology changes. PitNET TAFs secreted significant amounts of cytokines including CCL2, CCL11, VEGF-A, CCL22, IL-6, FGF-2 and IL-8. TAFs from PitNETs with cavernous sinus invasion secreted higher IL-6 levels compared to fibroblasts from non-invasive tumours (P = 0.027). Higher CCL2 release from TAFs correlated with more capillaries (r = 0.672, P = 0.004), and TAFs from PitNETs with a higher Ki-67 tended to secrete more CCL2 (P = 0.058). SST1 is the predominant somatostatin receptor in TAFs, and pasireotide decreased TAF-derived IL-6 by 80% (P < 0.001) and CCL2 by 35% (P = 0.038). GH3 cells treated with TAF-conditioned medium showed increased migration and invasion compared to cells treated with skin fibroblast-conditioned medium, with morphological and E-cadherin and ZEB1 expression changes suggesting epithelial-to-mesenchymal transition. TAF-derived cytokines may increase PitNET aggressiveness, alter angiogenesis and induce epithelial-to-mesenchymal transition changes. Pasireotide's inhibitory effect on TAF-derived cytokines suggest that this effect may play a role in its anti-tumour effects.

Chemokines modulate the tumour microenvironment in pituitary neuroendocrine tumours

Non-tumoural cells within the tumour microenvironment (TME) influence tumour proliferation, invasiveness and angiogenesis. Little is known about TME in pituitary neuroendocrine tumours (PitNETs). We aimed to characterise the role of TME in the aggressive behaviour of PitNETs, focusing on immune cells and cytokines. The cytokine secretome of 16 clinically non-functioning PitNETs (NF-PitNETs) and 8 somatotropinomas was assessed in primary culture using an immunoassay panel with 42 cytokines. This was correlated with macrophage (CD68, HLA-DR, CD163), T-lymphocyte (CD8, CD4, FOXP3), B-lymphocyte (CD20), neutrophil (neutrophil elastase) and endothelial cells (CD31) content, compared to normal pituitaries (NPs, n = 5). In vitro tumour-macrophage interactions were assessed by conditioned medium (CM) of GH3 (pituitary tumour) and RAW264.7 (macrophage) cell lines on morphology, migration/invasion, epithelial-to-mesenchymal transition and cytokine secretion. IL-8, CCL2, CCL3, CCL4, CXCL10, CCL22 and CXCL1 are the main PitNET-derived cytokines. PitNETs with increased macrophage and neutrophil content had higher IL-8, CCL2, CCL3, CCL4 and CXCL1 levels. CD8+ T-lymphocytes were associated to higher CCL2, CCL4 and VEGF-A levels. PitNETs had more macrophages than NPs (p < 0.001), with a 3-fold increased CD163:HLA-DR macrophage ratio. PitNETs contained more CD4+ T-lymphocytes (p = 0.005), but fewer neutrophils (p = 0.047) with a 2-fold decreased CD8:CD4 ratio. NF-PitNETs secreted more cytokines and had 9 times more neutrophils than somatotropinomas (p = 0.002). PitNETs with higher Ki-67 had more FOXP3+ T cells, as well as lower CD68:FOXP3, CD8:CD4 and CD8:FOXP3 ratios. PitNETs with "deleterious immune phenotype" (CD68^hiCD4^hiFOXP3^hiCD20^hi) had a Ki-67 ≥ 3%. CD163:HLA-DR macrophage ratio was positively correlated with microvessel density (p = 0.015) and area (p < 0.001). GH3 cell-CM increased macrophage chemotaxis, while macrophage-CM changed morphology, invasion, epithelial-to-mesenchymal transition and secreted cytokines of GH3 cells. PitNETs are characterised by increased CD163:HLA-DR macrophage and reduced CD8:CD4 and CD8:FOXP3 T cell ratios. PitNET-derived chemokines facilitate macrophage, neutrophil and T cell recruitment into the tumours which can determine aggressive behaviour.

Abstract 1103: The effects of neo-adjuvant chemotherapy on myeloid cells in high-grade serous ovarian cancer metastases

Many tumours have abundant macrophage populations. Tumour-associated macrophages (TAMs) frequently have tumour promoting roles and are associated with poor clinical outcome. We hypothesise that targeting TAMs in high-grade serous ovarian cancer (HGSOC) may improve response to chemotherapy.

We have assessed the effects of chemotherapy on TAM populations in human HGSOC obtained pre- and post-chemotherapy as well as in murine HGSOC models harbouring a relevant mutational profile. We find that chemotherapy treatment decreases TAM density within tumour areas. Furthermore, TAMs expressing markers known to associate with disease progression were decreased following chemotherapy. In vivo and in vitro we have demonstrated an up-regulation of inflammasome activation and TLR signalling in live myeloid cells following chemotherapy and have shown that macrophages are killed by chemotherapy at clinically relevant drug concentrations. These observations suggest a mechanism for TAM depletion and highlight chemotherapy induced activation of innate immunity in HGSOC.

The majority of HGSOC patients respond well to first line chemotherapy but will relapse and succumb to treatment resistant disease. We have developed a murine model of HGSOC relapse after first-line chemotherapy, which has the potential to extend translational studies into this clinically important area. We have found that TAMs are re-established in tumours at relapse, suggesting a clinically defined window of opportunity to target TAMs in HGSOC following first-line chemotherapy.

Overall, our results provide a rationale for targeted re-programming of TAMs in HGSOC after chemotherapy.

Citation Format: Owen M. Heath, Eleni Maniati, Chiara Belato, Ganga Gopinathan, Laura Lecker, Anissa Lakhani, Colin Pegrum, Jacqueline McDermott, Michelle Lockley, Desmond P. Barton, Frances Balkwill. The effects of neo-adjuvant chemotherapy on myeloid cells in high-grade serous ovarian cancer metastases [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 1103.

MON-460 Pasireotide Treatment Inhibits Cytokine Release from Pituitary Adenoma-Associated Fibroblasts: Is This Mechanism Playing a Key Role in Its Effect?

Introduction: Tumour-associated fibroblasts (TAFs) are important elements of the tumour microenvironment (TME) well-studied in several cancers, but their role in pituitary adenomas (PAs) has never been shown. We aimed to study the role of TAFs in PAs and its response to somatostatin analogues (SSA). Methods: TAFs were isolated from 11 freshly-cultured NFPAs and 5 GHomas as confirmed by vimentin and αSMA immunostaining. TAF presence in PAs was confirmed by immunohistochemistry, and further assessed with the gene-signature based method xCELL on a different set of samples. Macrophage infiltration, angiogenesis and epithelial-to-mesenchymal pathways were evaluated by immunohistochemistry for CD68, CD163, HLA-DR, E-cadherin, ZEB1 and CD31. TAFs secretome was assessed in vitro on culture supernatants, at baseline and after treatment with pasireotide (10^-7M) using Millipore MILLIPLEX human cytokine 42-plex. GH3 cells were treated with TAF-conditioned media (CM) and normal skin fibroblasts-CM (F-CM). Cell morphology (analysed by ImageJ), invasion and epithelial-to-mesenchymal pathways were assessed. Results: CCL2 and eotaxin-1 were identified as the top secreted cytokines in TAF supernatants, followed by VEGF-A, CCL22, IL-6, FGF-2 and IL-8. TAF secretomes from NFPAs and GHomas did not differ significantly. PAs with cavernous sinus invasion had higher TAF-derived IL-6 levels compared to non-invasive PAs (72.7±10.7 vs 43.9±6.3pg/mL; p=0.027), while there was a trend for TAFs from PAs with higher Ki67 to secrete more CCL2 (p=0.058). Correlation between macrophages and TAF-derived FGF-2 was found (r=0.499, p=0.049), and increased FGF-2 and CXCL1 levels were seen in PAs with a macrophage M2:M1 ratio≥2. CCL2 levels were correlated with microvessel area (r=0.672, p=0.004), whereas PDGF-AA was negatively correlated with E-cadherin immunoreactivity (r=-0.564, p=0.023). RT-qPCR analyses indicated that the sst1 receptor is the predominant somatostatin receptor expressed in TAFs, while sst2 and sst5 receptors are poorly expressed. Pasireotide treatment decreased TAF-derived IL-6 by 80% (p<0.001) and CCL2 by 35% (p=0.038). GH3 cells treated with TAF-CM showed epithelial-to-mesenchymal-like morphology and increased invasiveness in comparison to F-CM or untreated cells, as well as E-cadherin downregulation and ZEB1 upregulation. Conclusions: TAFs are present in the TME of PAs and display a biological role. TAF-derived cytokines may influence tumor and non-tumoral cells (such as macrophages) leading to increased invasiveness, as well as influence angiogenesis and epithelial-to-mesenchymal pathways in PAs, with IL-6 and CCL2 emerging as relevant mediators. The inhibitory effect of pasireotide on TAF secretome highlights a promising anti-tumoral effect of SSAs by directly targeting TAFs and thus modulating the TME in PAs.

MON-462 Cytokine Network in Pituitary Adenomas and Its Role in the Tumor Microenvironment: Focus on Macrophages

Introduction: Cytokines are important elements of the tumor microenvironment (TME) coordinating host responses against the tumor, promoting growth, invasion, angiogenesis and regulating non-tumoral cells in TME. Little is known regarding the cytokine network in pituitary adenomas (PAs) and its role in the TME. We aimed to characterise PA-derived cytokines to study their role in the TME of PAs. Methods: The cytokine secretome of culture supernatants from 27 human PAs (16 NFPAs, 9 GHomas, 1 TSHoma, 1 ACTHoma) was assessed using Millipore MILLIPLEX cytokine/chemokine 42-plex. IL-8 and CCL2 expression was further studied by RNAscope. Angiogenesis, macrophages and epithelial-to-mesenchymal transition were evaluated by immunohistochemistry for CD31, CD68, CD163, HLA-DR, E-cadherin and ZEB1. Macrophage infiltration in PAs and its phenotype was further assessed with the gene-signature based method xCELL. We have developed an in vitro model of pituitary cells (GH3) and macrophages (RAW264.7) and studied their interaction via assessing the effect of conditioned media. We documented cell morphology (ImageJ), migration and invasion (Boyden chambers), epithelial-to-mesenchymal transition pathway (RT-qPCR and immunocytochemistry) and secretome changes (cytokine array). Results: IL-8, CCL2, CCL3 and CCL4 are the main PA-derived cytokines, with CXCL1, CXCL10, CCL22 and CX3CL1 also secreted by most of these tumors. RNAscope data showed that CCL2 and IL-8 are mainly synthesised in the pituitary tumour cells. NFPAs secreted more cytokines than somatotropinomas, especially CCL2 (16x more), IL-8 (25x more) and CCL4 (27x more). PAs contained more macrophages than normal pituitary (4.9±0.7 vs 1.2±0.2%, p=0.007). Macrophage infiltration was associated with higher chemokine levels (CCL2, CCL3, CCL4, CXCL1 and IL-8). Macrophages in PAs belong to the CD163+ M2-subtype, while in normal pituitary M1-macrophages predominate, resulting in 3-fold increased M2:M1 ratio in PAs (p<0.001). These findings were confirmed with xCELL on a different set of PA samples. M2:M1 ratio correlated with microvessel density (r=0.509; p=0.008). Macrophage-conditioned media induced numerous effects on GH3 cells: more elongated, epithelial-to-mesenchymal transition-like cells, significantly increased migration and invasiveness, and altered GH3 cell cytokine secretome. On other hand, GH3 cell-conditioned media induced activation-associated morphological changes in RAW264.7 macrophages, increased chemotaxis and altered macrophage cytokine secretome. Conclusions: Primarily M2-subtype macrophages are present in the TME of PAs and their number is correlating with CCL2, IL-8, CCL3 and CCL4 release. NFPAs secrete higher levels of cytokines than somatotropinomas. Our data suggest that there is crosstalk between pituitary tumor cells and macrophages which may determine the biological behavior of PAs.

Abstract PR14: CRISPR/Cas9-mediated Trp53, Brca1, Brca2, Pten, and Nf1 knockout to generate improved murine models of ovarian high-grade serous carcinoma

Background: Transplantable murine models of ovarian high-grade serous carcinoma (HGSC) that recreate key mutations seen in the human disease are greatly needed. These models would assist investigation of the relationships between tumor genotype, chemotherapy response, and immune microenvironment. ID8 is a widely-used murine model of ovarian cancer. However, we previously showed that it is poorly characteristic of HGSC, with no functional alterations in key HGSC genes including Trp53, Brca1, Brca2, Pten, Nf1, and Rb1. We generated novel ID8 derivatives with single (Trp53-/-) and double (Trp53-/-;Brca2-/-) mutations using CRISPR/Cas9 gene editing.

Methods: We have now generated further ID8 derivatives: Trp53-/-;Brca1-/-, Trp53-/-;Pten-/- and Trp53-/-;Nf1-/-. In vitro, we assessed DNA double-strand break repair, and sensitivity to both platinum chemotherapy and PARP inhibition, as well as cytokine and chemokine production. In vivo, we investigated intraperitoneal growth, as well as immune cell infiltration into the tumor microenvironment.

Results: Assays of homologous recombination (HR) function confirm that loss of Brca1 function, but not Pten or Nf1, renders cells HR defective. This is accompanied by significant increases in sensitivity to both platinum and the PARP inhibitor rucaparib in Trp53-/-;Brca1-/- cells compared to Trp53-/-. Drug sensitivity in Trp53-/-;Pten-/- and Trp53-/-;Nf1-/- cells remains unchanged compared to Trp53-/- cells.

In vivo, loss of Pten and Nf1 significantly reduced time to reach humane endpoints following intraperiteonal injection (34 and 36.5 days respectively) compared to p53 loss alone (46 days, both p&lt;0.0001), while Brca1 loss had no effect on intraperitoneal growth (47 days).

There were significant differences in survival for the different genotypes following three doses of intraperitoneal cisplatin (5mg/kg on days 28, 35, and 42 only). Mice bearing control Trp53-/- tumors reached humane endpoint in a median of 81 days. Trp53-/-;Pten-/- and Trp53-/-;Nf1-/- tumors produced the worst survival (median 69 and 71 days, respectively; p&lt;0.01 for both compared to Trp53-/-). Survival was extended to 97 days for Trp53-/-;Brca1-/- (p=0.0003 compared to Trp53-/-), but even further to 113 days for Trp53-/-;Brca2-/- tumors (median 113 days), which was significantly longer than both Trp53-/- and Trp53-/-;Brca1-/- (p&lt;0.0001 for both).

In poor-prognosis Trp53-/-;Pten-/- and Trp53-/-;Nf1-/- tumors, whole-blood analysis of mice at endpoint shows a significant decrease in haemoglobin compared to single Trp53-/- tumors (p=0.0023). Furthermore, flow cytometry data show a significant increase in CD11b+;Ly6CG++ neutrophils in the ascites of mice compared to single Trp53-/-, suggesting an immunosuppressive microenvironment (p=0.0146). Analysis of whole blood at endpoint again shows a significant increase in neutrophils in mice bearing double Trp53-/-;Pten-/- tumors compared to single Trp53-/- (p=0.0203). Possible mechanisms suggested from cytokine array data include increased expression of CCL7 in Trp53-/-;Pten-/- cells, which is confirmed in tumors. Further work to characterize T-cell activation in these models is ongoing.

Conclusions: These novel ID8 models represent a new and simple tool to investigate the biology of HGSC. All cells will be made available to other researchers upon request.

This abstract is also being presented as Poster B61.

Citation Format: Josephine Walton, Malcolm Farquharson, Susan Mason, Julianna Blagih, Darren Ennis, Elaine Leung, Suzanne Dowson, Dimitris Athineos, Damiano Rami, David Stevenson, Seth Coffelt, Karen Blyth, Douglas Strathdee, Frances Balkwill, Karen Vousden, Michelle Lockley, Iain McNeish. CRISPR/Cas9-mediated Trp53, Brca1, Brca2, Pten, and Nf1 knockout to generate improved murine models of ovarian high-grade serous carcinoma. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr PR14.

Abstract A31: Mutant p53 increases integrin-ECM interactions in early HGSOC

Until recently, it was thought that high-grade serous ovarian cancer (HGSOC) arises from the ovarian surface epithelium (OSE). Now, it has become clear that the epithelium of the fallopian tube fimbriae is the starting point of many HGSOCs. Serous tubal intraepithelial carcinomas (STICs) are suggested to be the earliest form of HGSOC and show mutations in the p53 gene. Part of the neoplastic transformation into invasive HGSOC may be the initial adhesion of STIC cells to the surface of the ovary as a first site of metastasis. To examine the role of mutant p53 immortalized fallopian tube secretory epithelial (FTSE) cells in the early onset of HGSOC, we used mechanically tunable hydrogels and developed a protocol to obtain decellularized human ovary scaffolds for 3D cell cultures. Stable expression of mutant p53 in FTSE cells promoted adhesion to hydrogel matrices and invasion into decellularized ovary scaffolds. Next, we sought to analyze the extracellular matrix (ECM) landscape of human fallopian tube and ovary tissues and identified proteins with a high affinity to integrin αvβ3. Mutant p53 FTSE cells had increased levels of integrin αvβ3 and decreased adhesive potential upon integrin αvβ3 blockage compared to wild-type FTSE cells. The results indicate that FTSE cells expressing mutant p53 upregulate integrin expression, which in turn alters their tissue-specific ECM interactions. Our findings give new insights in the early onset of HGSOC and may help to understand the role of p53 in the cells of origin of HGSOC.

Citation Format: Laura SM Lecker, Caterina Trevisan, Robin Delaine-Smith, Eleni Maniati, Oliver Pearce, Christoph Meinert, Marcin Iwanicki, Ronny Drapkin, Daniela Loessner, Frances Balkwill. Mutant p53 increases integrin-ECM interactions in early HGSOC. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr A31.

A guiding map for inflammation

Biologists, physicians and immunologists have contributed to the understanding of the cellular participants and biological pathways involved in inflammation. Here, we provide a general guide to the cellular and humoral contributors to inflammation as well as to the pathways that characterize inflammation in specific organs and tissues.

Upregulation of amphiregulin on CD14++CD16- (classical) monocytes in non-small cell lung cancer

e14612

Background: Amphiregulin is an EGFR ligand which contributes to many of the hallmarks of cancer including angiogenesis and metastasis. Recent studies demonstrate that Amphiregulin promotes an immunosuppressive tumour microenvironment by modulating the expression of T regulatory cells. Although its expression has been described on a variety of immune cells and tumour cells, there is no published data on Amphiregulin expression by monocytes to date. Previous work by this group has demonstrated that monocytes from non-small cell lung cancer patients are phenotypically and genomically different compared to healthy volunteers. This study aims to further investigate the differing genomic profile of monocytes in non-small cell lung cancer. Methods: Gene expression profiling was performed on CD14++CD16- (classical) monocytes of newly diagnosed patients with Stage IV non-small cell lung cancer (n = 6) and age-matched healthy volunteers (n = 6) using Affymetrix Human U133 Plus 2.0 array. Validation of differentially expressed genes of interest (including Amphiregulin) at mRNA level was performed using real-time PCR with TaqMan gene expression assays on independent patient (n = 6) and healthy volunteer cohorts (n = 6). Differential protein expression of Amphiregulin from the monocytes of healthy volunteers (n = 3) and non-small cell lung cancer patients (n = 3) was validated using ELISA technology. Results: Amphiregulin is one of the most upregulated genes on classical monocytes in non-small cell lung cancer patients compared to healthy volunteers (p = 0.001). The increased expression of Amphiregulin was confirmed on qPCR validation in an independent cohort of non-small cell lung cancer patients (p < 0.05) as well as in the original group (p < 0.001). Amphiregulin was also found to be increased at protein level on CD14++CD16- monocytes of non-small cell lung cancer compared to healthy volunteers. (p = 0.37). Conclusions: Amphiregulin is overexpressed by classical monocytes in non-small cell lung cancer and this over-expression is confirmed at mRNA and protein level. The production of Amphiregulin has not been ascribed to human monocytes in non-small cell lung cancer making its overexpression in this study a unique finding.

CXCR2 Inhibition Profoundly Suppresses Metastases and Augments Immunotherapy in Pancreatic Ductal Adenocarcinoma

CXCR2 has been suggested to have both tumor-promoting and tumor-suppressive properties. Here we show that CXCR2 signaling is upregulated in human pancreatic cancer, predominantly in neutrophil/myeloid-derived suppressor cells, but rarely in tumor cells. Genetic ablation or inhibition of CXCR2 abrogated metastasis, but only inhibition slowed tumorigenesis. Depletion of neutrophils/myeloid-derived suppressor cells also suppressed metastasis suggesting a key role for CXCR2 in establishing and maintaining the metastatic niche. Importantly, loss or inhibition of CXCR2 improved T cell entry, and combined inhibition of CXCR2 and PD1 in mice with established disease significantly extended survival. We show that CXCR2 signaling in the myeloid compartment can promote pancreatic tumorigenesis and is required for pancreatic cancer metastasis, making it an excellent therapeutic target.

Centre of the Cell: Science Comes to Life

Centre of the Cell is a unique biomedical science education centre, a widening participation and outreach project in London's East End. This article describes Centre of the Cell's first five years of operation, the evolution of the project in response to audience demand, and the impact of siting a major public engagement project within a research laboratory.

Abstract 455: B cells actively participate to the anti-cancer immune response in high grade serous ovarian cancer metastases

Intra-tumor B cells and immunoglobulin signatures have been associated with a better clinical prognosis in ovarian cancer (Iglesia et al, 2014; Nielsen et al, 2012). However little is known about the mechanisms by which B cells influence the anti-cancer immune response. The aim of our research is to evaluate B cell dependent anti-cancer immune responses in peritoneal metastases in high grade serous ovarian cancer (HGSOC) patients.

We have found that in these peritoneal metastases, B cells are mainly located in lymphoid structures and a high proportion of these (60%) display a CD27+ memory phenotype. HGSOC B cells are able to secrete Th1 related cytokines as well as high levels of IL8, which is a chemo-attractant for T cells, granulocytes and macrophages. Interestingly CD4+ and CD8+ T cells express high levels of the IL8 receptor, CXCR1, which suggests B cells help recruiting T cells to lymphoid structures.

Plasma cells were also detected in the peritoneal metastases along with IgG deposits. Secreted IgGs were mainly located in stromal areas suggesting that the associated matrix may prevent their infiltration into tumour islets and/or that they target specific stromal antigens.

Interestingly, we observed that neoadjuvant chemotherapy and residual disease after chemotherapy influence the type of IgG subclasses expressed in the omentum of HGSOC patients. Chemotherapy enhances the expression of IgG1, IgG2 and IgG3 immunoglobulins in omentum with residual disease. This supports the notion that B cells are involved in the anti-tumor immune response in HGSOC metastases.

In conclusion, our data suggest that B cells actively participate to the anti-tumor immune response in HGSOC metastases. This response is preferentially Th1 oriented through the production of cytokines and dominant expression of IgG1 immunoglobulins. Enhancing the B cell dependent anti-tumor immune response could be a potential strategy for the treatment of HGSOC patients.

Iglesia MD, Vincent BG, Parker JS, Hoadley KA, Carey LA, Perou CM, Serody JS (2014) Prognostic B-cell signatures using mRNA-seq in patients with subtype-specific breast and ovarian cancer. Clin Cancer Res 20: 3818-3829

Nielsen JS, Sahota RA, Milne K, Kost SE, Nesslinger NJ, Watson PH, Nelson BH (2012) CD20+ tumor-infiltrating lymphocytes have an atypical CD27- memory phenotype and together with CD8+ T cells promote favorable prognosis in ovarian cancer. Clin Cancer Res 18: 3281-3292

Citation Format: Anne Montfort, Steffen Boehm, Thomas Dowe, Joanne Topping, Michelle Lockley, Melania Capasso, Frances Balkwill. B cells actively participate to the anti-cancer immune response in high grade serous ovarian cancer metastases. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 455. doi:10.1158/1538-7445.AM2015-455

Interleukin-6 Stimulates Defective Angiogenesis

The cytokine IL6 has a number of tumor-promoting activities in human and experimental cancers, but its potential as an angiogenic agent has not been fully investigated. Here, we show that IL6 can directly induce vessel sprouting in the ex vivo aortic ring model, as well as endothelial cell proliferation and migration, with similar potency to VEGF. However, IL6-stimulated aortic ring vessel sprouts had defective pericyte coverage compared with VEGF-stimulated vessels. The mechanism of IL6 action on pericytes involved stimulation of the Notch ligand Jagged1 as well as angiopoietin2 (Ang2). When peritoneal xenografts of ovarian cancer were treated with an anti-IL6 antibody, pericyte coverage of vessels was restored. In addition, in human ovarian cancer biopsies, there was an association between levels of IL6 mRNA, Jagged1, and Ang2. Our findings have implications for the use of cancer therapies that target VEGF or IL6 and for understanding abnormal angiogenesis in cancers, chronic inflammatory disease, and stroke.

B regulatory cells in cancer

B regulatory cells are a newly described subpopulation of B cells that appear to play important roles in autoimmunity and more recently, in cancer. In this review we summarize our current knowledge of B regulatory cells, as well as the body of evidence pointing towards a role for B cells in general, and B regulatory cells in particular, in promoting tumor growth.

Abstract 4391: CD20 as a target for therapy in solid tumors

Using the K14-HPV16 mouse model of squamous carcinogenesis (SCC), we previously reported that B cells foster neoplastic progression through deposition of immunoglobulin complexes in premalignant tissue via Fcα receptor-dependent activation of recruited myeloid cells. Here we evaluated therapeutic interventions targeting these pathways in preclinical trials through administration of depleting αCD20 antibody and small molecule inhibitor of Syk kinase. Both approaches harbored efficacy in preventing premalignant progression to the dysplastic/carcinoma in situ state. Screening a diverse spectrum of human solid tumors revealed SCCs of the vulva, head and neck, as well as pancreatic ductal adenocarcinomas (PDAC) as scoring positively for “signatures” of B cell or plasma cell infiltration, i.e. Ig or CD20 mRNA expression, thereby identifying carcinomas potentially amenable to anti-B cell therapies. Accordingly, B cell-deficient mice failed to support growth of either transplantable orthotopic SCC or PDAC. While administration of αCD20 mAB as a single agent was inefficient in impeding growth of preexisting SCCs, when delivered in combination with cytotoxic chemotherapy, e.g., paclitaxel, carboplatin or cisplatin, αCD20 mAb significantly improved chemotherapeutic response and improved survival by a mechanism dependent on CD8+ T cells. These data reveal that blocking protumorigenic programs regulating by humoral immunity, in combination with chemotherapy, effectively reprograms the tumor immune microenvironment and improves outcome. The authors acknowledge generous support from the NIH/NCI (R01CA130980, R01CA13256, R01CA140943, R01CA15531), the Department of Defense (W81XWH-09-1-0342, W81XWH-10-BCRP-EOHS-EXP) and the Susan G Komen Foundation (KG111084)

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 4391. doi:1538-7445.AM2012-4391

Abstract 49: Targeting the TNF network in human ovarian cancer - A systems biology approach

In a recent publication (Kulbe et al Cancer Res 2011 epub ahead of print), we have shown how key pathways in cancer-related inflammation and Notch signaling are part of an autocrine malignant cell network in high-grade serous ovarian cancer, HGSOC. This network, that we have named the TNF network, has paracrine actions on angiogenesis, the stromal signature and the immune cell infiltrate in HGSOC. We have now used a systems biology approach, combining data from phospho-proteomic mass spectrometry and gene expression array analysis, to define the best therapeutic targets within the network and to identify drugs that may synergise with cytokine and chemokine inhibitors. First, we established a hierarchy of kinases involved in the TNF network and analyzed the constitutively active kinases in one of the high TNF network cell lines. Of 45 constitutively active kinases, 33 of these kinases showed direct interactions with each other. Next, we mapped gene expression microarray data onto the Connectivity Map of drugs in order to identify compounds having an effect on transcription similar to that of the TNF network. Among the identified candidate drugs were luteolin, apigenin and resveratrol. One of the known targets of this class of drugs is the protein kinase Casein kinase II (CSNK2A1), a kinase activated in association with the TNF network. In conclusion, we have identified kinases, particularly CK2, associated with the TNF network that may play a central role in sustaining the cytokine network and/or mediating its effects in ovarian cancer. We believe our findings have implications for our understanding of ovarian cancer biology and the development of new and more effective treatments for this disease.

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 49. doi:1538-7445.AM2012-49

Paraneoplastic thrombocytosis in ovarian cancer

BACKGROUND

The mechanisms of paraneoplastic thrombocytosis in ovarian cancer and the role that platelets play in abetting cancer growth are unclear.

METHODS

We analyzed clinical data on 619 patients with epithelial ovarian cancer to test associations between platelet counts and disease outcome. Human samples and mouse models of epithelial ovarian cancer were used to explore the underlying mechanisms of paraneoplastic thrombocytosis. The effects of platelets on tumor growth and angiogenesis were ascertained.

RESULTS

Thrombocytosis was significantly associated with advanced disease and shortened survival. Plasma levels of thrombopoietin and interleukin-6 were significantly elevated in patients who had thrombocytosis as compared with those who did not. In mouse models, increased hepatic thrombopoietin synthesis in response to tumor-derived interleukin-6 was an underlying mechanism of paraneoplastic thrombocytosis. Tumor-derived interleukin-6 and hepatic thrombopoietin were also linked to thrombocytosis in patients. Silencing thrombopoietin and interleukin-6 abrogated thrombocytosis in tumor-bearing mice. Anti-interleukin-6 antibody treatment significantly reduced platelet counts in tumor-bearing mice and in patients with epithelial ovarian cancer. In addition, neutralizing interleukin-6 significantly enhanced the therapeutic efficacy of paclitaxel in mouse models of epithelial ovarian cancer. The use of an antiplatelet antibody to halve platelet counts in tumor-bearing mice significantly reduced tumor growth and angiogenesis.

CONCLUSIONS

These findings support the existence of a paracrine circuit wherein increased production of thrombopoietic cytokines in tumor and host tissue leads to paraneoplastic thrombocytosis, which fuels tumor growth. We speculate that countering paraneoplastic thrombocytosis either directly or indirectly by targeting these cytokines may have therapeutic potential. (Funded by the National Cancer Institute and others.).

Sequential genetic change at the TP53 and chemokine receptor CXCR4 locus during transformation of human ovarian surface epithelium

Early genetic events in the development of high-grade serous ovarian cancer, HGSOC, may define the molecular basis of the profound structural and numerical instability of chromosomes in this disease. To discover candidate genetic changes we sequentially passaged cells from a karyotypically normal hTERT immortalised human ovarian surface epithelial line (IOSE25) resulting in the spontaneous formation of colonies in soft agar. Cell lines (TOSE 1 and 4) established from these colonies had an abnormal karyotype and altered morphology but were not tumorigenic in immunodeficient mice.

TOSE cells showed loss of heterozygosity at TP53, increased nuclear p53 immunoreactivity and altered expression profile of p53 target genes. The parental IOSE25 cells contained a missense, heterozygous R175H mutation in TP53 whereas TOSE cells had loss of heterozygosity at the TP53 locus with a new R273H mutation at the previous wild-type TP53 allele.

Cytogenetic and array CGH analysis of TOSE cells also revealed a focal genomic amplification of CXCR4, a chemokine receptor commonly expressed by HGSOC cells. TOSE cells had increased functional CXCR4 protein and its abrogation reduced epidermal growth factor receptor, EGFR, expression, as well as colony size and number. The CXCR4 ligand, CXCL12, was epigenetically silenced in TOSE cells and its forced expression increased TOSE colony size. TOSE cells had other cytogenetic changes typical of those seen in HGSOC ovarian cancer cell lines and biopsies. In addition, enrichment of CXCR4 pathway in expression profiles from HGSOC correlated with enrichment of a mutated TP53 gene expression signature and of EGFR pathway genes.

Our data suggest that mutations in TP53 and amplification of the CXCR4 gene locus may be early events in the development of HGSOC, and associated with chromosomal instability.

IL6-STAT3-HIF signaling and therapeutic response to the angiogenesis inhibitor sunitinib in ovarian clear cell cancer

PURPOSE

Ovarian clear cell adenocarcinoma (OCCA) is an uncommon histotype that is generally refractory to platinum-based chemotherapy. We analyze here the most comprehensive gene expression and copy number data sets, to date, to identify potential therapeutic targets of OCCA.

EXPERIMENTAL DESIGN

Gene expression and DNA copy number were carried out using primary human OCCA tumor samples, and findings were confirmed by immunohistochemistry on tissue microarrays. Circulating interleukin (IL) 6 levels were measured in serum from patients with OCCA or high-grade serous cancers and related to progression-free and overall survival. Two patients were treated with sunitinib, and their therapeutic responses were measured clinically and by positron emission tomography.

RESULTS

We find specific overexpression of the IL6-STAT3-HIF (interleukin 6-signal transducer and activator of transcription 3-hypoxia induced factor) pathway in OCCA tumors compared with high-grade serous cancers. Expression of PTHLH and high levels of circulating IL6 in OCCA patients may explain the frequent occurrence of hypercalcemia of malignancy and thromboembolic events in OCCA. We describe amplification of several receptor tyrosine kinases, most notably MET, suggesting other potential therapeutic targets. We report sustained clinical and functional imaging responses in two OCCA patients with chemotherapy-resistant disease who were treated with sunitinib, thus showing significant parallels with renal clear cell cancer.

CONCLUSIONS

Our findings highlight important therapeutic targets in OCCA, suggest that more extensive clinical trials with sunitinib in OCCA are warranted, and provide significant impetus to the growing realization that OCCA is molecularly and clinically distinct to other forms of ovarian cancer.

Guidelines for the welfare and use of animals in cancer research

Animal experiments remain essential to understand the fundamental mechanisms underpinning malignancy and to discover improved methods to prevent, diagnose and treat cancer. Excellent standards of animal care are fully consistent with the conduct of high quality cancer research. Here we provide updated guidelines on the welfare and use of animals in cancer research. All experiments should incorporate the 3Rs: replacement, reduction and refinement. Focusing on animal welfare, we present recommendations on all aspects of cancer research, including: study design, statistics and pilot studies; choice of tumour models (e.g., genetically engineered, orthotopic and metastatic); therapy (including drugs and radiation); imaging (covering techniques, anaesthesia and restraint); humane endpoints (including tumour burden and site); and publication of best practice.