Transcriptomic Analysis to Uncover the Mechanism of Radiosensitization of AR-Positive Triple Negative Breast Cancers with AR Inhibition

PURPOSE/OBJECTIVE(S)

The androgen receptor (AR) has been shown to drive tumor growth in triple negative breast cancers (TNBC), and previous work demonstrated AR inhibition as a strategy for radiosensitization in AR-positive (AR+) TNBC. Despite its role in radioresistance, the mechanistic role of AR in response to radiation therapy (RT) remains unknown, as does the benefit of 2nd generation anti-androgens in this context. We hypothesized that all 2nd generation anti-AR therapy would radiosensitize similarly and that canonical AR transcriptional function was responsible for radioresistance in these models.

MATERIALS/METHODS

Radiosensitization was assessed using 2nd generation AR antagonists (apalutamide, enzalutamide, and darolutamide) using clonogenic survival assays in MDA-MB-453, SUM185, MFM-223, and MDA-MB-231 cells at 2-6Gy. Cellular fractionation experiments were performed and quantitated to determine the location of the AR protein in cells treated with AR agonists +/- RT. RNA Seq was performed and transcriptomic approaches were used (Advaita iPathway analysis) to investigate AR-mediated effects in response to RT.

RESULTS

Inhibition with the 2nd generation anti-androgens enzalutamide and apalutamide is sufficient to radiosensitize AR+ TNBC models (rER: 1.34-1.41); while darolutamide had no effect on radiosensitivity (rER: 0.96-1.11). Additionally, TNBC cells with low AR expression were not radiosensitized by AR inhibition with any drug (rER: 0.96-1.03). While stimulation with the synthetic androgen methyltrienolone R1881 is sufficient to induce nuclear translocation of AR in AR+ TNBC cells, AR inhibition with enzalutamide, apalutamide, or darolutamide blocked AR nuclear translocation under growth conditions with charcoal stripped serum or fetal bovine serum. When cells are treated with R1881+RT, nuclear translocation of AR was induced at similar or greater levels compared to R1881 alone in AR+ TNBC cells. Combination treatment of RT with enzalutamide in the presence of hormones reduced nuclear localization of AR (32-39% reduction) compared to RT alone. RNA-sequencing after RT identified transcriptional changes potentially regulated by AR+RT, including changes in the NHEJ pathway genes. Additionally, pathway analyses in these models demonstrated changes in the MAPK/ERK signaling pathway, among others, that may regulate RT resistance in AR+ TNBC models.

CONCLUSION

Most 2nd generation anti-androgens confer radiosensitization in AR+ TNBC models with cellular localization changes of AR noted after RT. The known structural differences amongst 2nd generation anti-androgens may account for differences in radiosensitization noted. Furthermore, AR-mediated radioresistance may be due, at least in part, to downstream MAPK/ERK signaling. This work builds on the mechanistic understanding of AR-mediated radioresistance in AR+ TNBC and may expose vulnerabilities to overcome resistance to combination treatment with AR inhibition and RT.

Reinventing the public square and early educational settings through culturally informed, community co-design: Playful Learning Landscapes

What if the environment could be transformed in culturally-responsive and inclusive ways to foster high-quality interactions and spark conversations that drive learning? In this article, we describe a new initiative accomplishing this, called Playful Learning Landscapes (PLL). PLL is an evidence-based initiative that blends findings from the science of learning with community-based participatory research to transform physical public spaces and educational settings into playful learning hubs. Here, we describe our model for conducting this research, which is mindful of three key components: community input, how children learn best, and what children need to learn to be successful in the 21st century economy. We describe how this model was implemented in two PLL case studies: one in a predominantly Latine community and the second in early childhood education classrooms. Furthermore, we describe how research employing our model can be rigorously and reliably evaluated using observational and methodological tools that respond to diverse cultural settings and learning outcomes. For example, our work evaluates how PLL impacts adult-child interaction quality and language use, attitudes about play and learning, and community civic engagement. Taken together, this article highlights new ways to involve community voices in developmental and educational research and provides a model of how science can be translated into practice and evaluated in culturally responsive ways. This synthesis of our process and evaluation can be used by researchers, policymakers, and educators to reimagine early educational experiences with an eye toward the built environment that children inhabit in everyday life, creating opportunities that foster lifelong learning.

Perceptual Access Reasoning (PAR) in Developing a Representational Theory of Mind

An important part of children's social and cognitive development is their understanding that people are psychological beings with internal, mental states including desire, intention, perception, and belief. A full understanding of people as psychological beings requires a representational theory of mind (ToM), which is an understanding that mental states can faithfully represent reality, or misrepresent reality. For the last 35 years, researchers have relied on false‐belief tasks as the gold standard to test children's understanding that beliefs can misrepresent reality. In false‐belief tasks, children are asked to reason about the behavior of agents who have false beliefs about situations. Although a large body of evidence indicates that most children pass false‐belief tasks by the end of the preschool years, the evidence we present in this monograph suggests that most children do not understand false beliefs or, surprisingly, even true beliefs until middle childhood. We argue that young children pass false‐belief tasks without understanding false beliefs by using perceptual access reasoning (PAR). With PAR, children understand that seeing leads to knowing in the moment, but not that knowing also arises from thinking or persists as memory and belief after the situation changes. By the same token, PAR leads children to fail true‐belief tasks. PAR theory can account for performance on other traditional tests of representational ToM and related tasks, and can account for the factors that have been found to correlate with or affect both true‐ and false‐belief performance. The theory provides a new laboratory measure which we label the belief understanding scale (BUS). This scale can distinguish between a child who is operating with PAR versus a child who is understanding beliefs. This scale provides a method needed to allow the study of the development of representational ToM.

In this monograph, we report the outcome of the tests that we have conducted of predictions generated by PAR theory. The findings demonstrated signature PAR limitations in reasoning about the mind during the ages when children are hypothesized to be using PAR. In Chapter II, secondary analyses of the published true‐belief literature revealed that children failed several types of true‐belief tasks.

Chapters III through IX describe new empirical data collected across multiple studies between 2003 and 2014 from 580 children aged 4–7 years, as well as from a small sample of 14 adults. Participants were recruited from the Phoenix, Arizona metropolitan area. All participants were native English‐speakers. Children were recruited from university‐sponsored and community preschools and daycare centers, and from hospital maternity wards. Adults were university students who participated to partially fulfill course requirements for research participation. Sociometric data were collected only in Chapter IX, and are fully reported there.

In Chapter III, minor alterations in task procedures produced wide variations in children's performance in 3‐option false‐belief tasks. In Chapter IV, we report findings which show that the developmental lag between children's understanding ignorance and understanding false belief is longer than the lag reported in previous studies. In Chapter V, children did not distinguish between agents who have false beliefs versus agents who have no beliefs. In Chapter VI, findings showed that children found it no easier to reason about true beliefs than to reason about false beliefs. In Chapter VII, when children were asked to justify their correct answers in false‐belief tasks, they did not reference agents’ false beliefs. Similarly, in Chapter VIII, when children were asked to explain agents’ actions in false‐belief tasks, they did not reference agents’ false beliefs. In Chapter IX, children who were identified as using PAR differed from children who understood beliefs along three dimensions—in levels of social development, inhibitory control, and kindergarten adjustment.

Although the findings need replication and additional studies of alternative interpretations, the collection of results reported in this monograph challenges the prevailing view that representational ToM is in place by the end of the preschool years. Furthermore, the pattern of findings is consistent with the proposal that PAR is the developmental precursor of representational ToM. The current findings also raise questions about claims that infants and toddlers demonstrate ToM‐related abilities, and that representational ToM is innate.

The Path to Fully Representational Theory of Mind: Conceptual, Executive, and Pragmatic Challenges

Although an explicit Theory of Mind (ToM) has been found to develop around 4 years of age in Western societies, recent work showing that 4- and 5-year-olds fail modified versions of False Belief tasks as well as seemingly easier True Belief tasks calls into question the robustness of preschoolers’ belief understanding. Some have argued these findings illustrate children’s conceptual limitations in their understanding of belief that are masked by standard False Belief tasks. However, others claim these examples of children’s failure can be explained by pragmatics of the testing situation, rather than conceptual limitations. Given the documented relation between ToM and executive function, an unexamined possibility is that children’s failure can be explained by certain executive demands. In the current study, we examined the relation between typically developing 4- (n = 43) and 5-year-olds’ (n = 42) performance on traditional and modified False Belief tasks, True Belief tasks, and one component of executive functioning - working memory. We found that children performed worse on modified False Belief tasks and True Belief tasks compared to standard 2-option False Belief tasks, and that working memory was related to modified 3-option contents False Belief performance. These results suggest that a fully representational ToM, one that is stable in the context of increased conceptual, executive, and pragmatic demands, may develop later than traditional accounts have assumed.

Varieties of trust in preschoolers' learning and practical decisions

Keeping commitments to others can be difficult, and we know that people sometimes fail to keep them. How does a speaker's ability to keep commitments affect children's practical decisions to trust and their epistemic decisions to learn? An amassing body of research documents children's trust in testimonial learning decisions, which can be moved in the face of epistemic and moral evidence about an agent. However, other bases for trust go largely unexplored in this literature, such as interpersonal reasons to trust. Here, we investigated how direct bids for interpersonal trust in the form of making commitments, or obligations to the listener, influence a range of decisions toward that agent. We found that 3- and 4-year-olds' (N = 75) practical decisions to wait and to share were moved as a function of a person's commitment-keeping ability, but epistemic decisions to learn were not. Keeping one's commitments may provide children with interpersonal reasons to trust, reasons that may function in ways distinct from the considerations that bear on accepting a claim.

Trusting others: shared reality in testimonial learning

Much of early learning depends on others, and the transmission of testimony presents children with a range of opportunities to learn about and from other people. Much work has focused on children's ability to select or prefer particular sources of information based on various epistemic (e.g. accuracy, reliability, perceptual access, expertise) and moral (e.g. benevolence, group membership, honesty) characteristics. Understanding the mechanisms by which such selective preferences emerge has been couched primarily in frameworks that treat testimony as a source of inductive evidence, and that treat children's trust as an evidence-based inference. However, there are other distinct interpersonal considerations that support children's trust towards others, considerations that influence who children learn from as well as other practical decisions. Broadening our conception of trust and considering the interpersonal reasons we have to trust others can both strengthen our current understanding of the role that trust plays in children's learning and practical decisions as well as provide a more holistic picture of how children participate in a shared reality with their family, peers, and communities.

“They Will Post a Law About Playing Soccer” and Other Ethnic/Racial Microaggressions in Organized Activities Experienced by Mexican-Origin Families

Organized activities have been found to provide positive experiences for Latino adolescents to develop confidence and learn critical life skills; however, these programs are sometimes a context where youth encounter negative experiences related to ethnic/racial microaggressions (ERMs). This qualitative study explores the types of ERMs that Mexican-origin parents and adolescents encountered in their organized activities experience. Parents were mainly concerned about SB-1070 and the associated law enforcement practices that posed a threat to transporting their children to and from the organized activity site. Adolescents reported that they encountered overt (e.g., ethnic teasing) as well as covert forms of discriminatory behavior (e.g., implicit ethnic stereotypes) from peers and adult leaders. Attention to the processes of ERM is critical to helping practitioners promote positive intergroup relations so that more Latinos will participate and stay active in organized activities.

Concentrations of lead in blood, hair and saliva of German children living in three different areas of traffic density

Lead contents in hair, whole blood and saliva were determined for 245 healthy children (121 male, 124 female, age: 8-10 years) from three residential areas of Düsseldorf (North-Rhine-Westphalia, Germany) with different traffic densities. The geometric mean for the lead content in hair was found to be 0.87 microg/g (range: 0.2-9.9 microg/g) for the entire test group. While the levels of lead in hair in the suburban population were significantly lower than in the two city centre populations, no significant difference concerning the lead content in hair could be detected in the latter. The geometric mean for lead concentration in whole blood amounted to 25.0 microg/l (range: 8.0-154 microg/l). There was no significant difference between the sub-groups. The lead concentrations found in saliva were rather low (range: < 1.5-47.0 microg/l). Of the values, 89% were below the detection limit of 1.5 microg/l. Due to reduced levels of lead in fuel, the present study exposes that the amount of lead in the children examined has further decreased compared to preceding surveys. The correlation between the lead content in hair and the road traffic density was not corroborated by the findings with regard to amounts of lead found in blood, indicating that residual lead from fuel does not result in a substantial burden of lead found in the whole body. In contrast to levels of lead found in blood, levels of lead found in hair may be influenced more by environmental conditions. Saliva is not a suitable material for biological monitoring with respect to lead exposure in children.

Mercury concentrations in urine, scalp hair, and saliva in children from Germany

Mercury levels measured in urine, hair, and saliva of 245 German children (8-10 years old) are reported. Mercury concentrations in urine ranged between <0.1 and 5.3 microg/l [geometric mean (GM) 0.26 microg/l or 0.25 microg/g creatinine; median for both, 0.22 in microg/l and microg/g, respectively]. Using multiple linear regression analysis, two predictors have been found accounting for 25.3% of the variance of mercury levels in urine: the number of teeth with amalgam fillings (23.2%) and the number of defective amalgam fillings (2.1%). The mercury content in hair ranged from <0.06 to 1.7 microg/g (GM 0.18 microg/g; median 0.18 microg/g). The frequency of fish consumption, the smoking habits of the parents, and the age of the children accounted for 20.4% of the variance of mercury levels in hair. The correlation between the hair mercury content and urine mercury concentration was low (r=0.297). Mercury levels in saliva ranged between <0.32 and 4.5 microg/l (median 0.16 microg/l). The mercury concentration in saliva was below the limit of quantification of 0.32 microg/l in more than 70% of the samples. Mercury analysis in urine is suitable to estimate mercury exposure due to amalgam fillings, whereas hair mercury better reflects mercury intake by fish consumption. Up to now, saliva does not seem to be a suitable tool to monitor the mercury burden, at least not at low exposure levels.