Nf1 deficiency modulates the stromal environment in the pretumorigenic rat mammary gland.

Background: Neurofibromin, coded by the NF1 tumor suppressor gene, is the main negative regulator of the RAS pathway and is frequently mutated in various cancers. Women with Neurofibromatosis Type I (NF1)-a tumor predisposition syndrome caused by a germline NF1 mutation-have an increased risk of developing aggressive breast cancer with poorer prognosis. The mechanism by which NF1 mutations lead to breast cancer tumorigenesis is not well understood. Therefore, the objective of this work was to identify stromal alterations before tumor formation that result in the increased risk and poorer outcome seen among NF1 patients with breast cancer. Approach: To accurately model the germline monoallelic NF1 mutations in NF1 patients, we utilized an Nf1-deficient rat model with accelerated mammary development before presenting with highly penetrant breast cancer. Results: We identified increased collagen content in Nf1-deficient rat mammary glands before tumor formation that correlated with age of tumor onset. Additionally, gene expression analysis revealed that Nf1-deficient mature adipocytes in the rat mammary gland have increased collagen expression and shifted to a fibroblast and preadipocyte expression profile. This alteration in lineage commitment was also observed with in vitro differentiation, however, flow cytometry analysis did not show a change in mammary adipose-derived mesenchymal stem cell abundance. Conclusion: Collectively, this study uncovered the previously undescribed role of Nf1 in mammary collagen deposition and regulating adipocyte differentiation. In addition to unraveling the mechanism of tumor formation, further investigation of adipocytes and collagen modifications in preneoplastic mammary glands will create a foundation for developing early detection strategies of breast cancer among NF1 patients.

Spatial transcriptomics reveals molecular dysfunction associated with cortical Lewy pathology.

A key hallmark of Parkinson's disease (PD) is Lewy pathology. Composed of α-synuclein, Lewy pathology is found both in dopaminergic neurons that modulate motor function, and cortical regions that control cognitive function. Recent work has established the molecular identity of dopaminergic neurons susceptible to death, but little is known about cortical neurons susceptible to Lewy pathology or molecular changes induced by aggregates. In the current study, we use spatial transcriptomics to capture whole transcriptome signatures from cortical neurons with α-synuclein pathology compared to neurons without pathology. We find, both in PD and related PD dementia, dementia with Lewy bodies and in the pre-formed fibril α-synucleinopathy mouse model, that specific classes of excitatory neurons are vulnerable to developing Lewy pathology. Further, we identify conserved gene expression changes in aggregate-bearing neurons that we designate the Lewy-associated molecular dysfunction from aggregates (LAMDA) signature. Neurons with aggregates downregulate synaptic, mitochondrial, ubiquitin-proteasome, endo-lysosomal, and cytoskeletal genes and upregulate DNA repair and complement/cytokine genes. Our results identify neurons vulnerable to Lewy pathology in the PD cortex and describe a conserved signature of molecular dysfunction in both mice and humans.

Ex Vivo Patient-Derived Explant Model for Neurofibromatosis Type 1-Related Cutaneous Neurofibromas.

Cutaneous neurofibromas (CNFs) are benign tumors that occur in the dermis of individuals with the inherited tumor predisposition disorder, neurofibromatosis type 1. CNFs cause disfigurement, pain, burning, and itching, resulting in substantially reduced QOL in patients with neurofibromatosis type 1. CNFs are benign tumors that exhibit cellular and molecular heterogeneity, making it difficult to develop tractable in vitro or in vivo models. As a result, CNF research and drug discovery efforts have been limited. To address this need, we developed a reproducible patient-derived explant (PDE) ex vivo culture model using CNF tumors from patients with neurofibromatosis type 1. CNF PDEs remain viable in culture for over 9 days and recapitulate the cellular composition and molecular signaling of CNFs. Using CNF PDEs as a model system, we found that proliferation was associated with increased T-cell infiltration. Furthermore, we identified a pattern of reciprocal inflammatory signaling in CNF PDEs in which tumors rely on prostaglandin or leukotriene-mediated signaling pathways. As proof of principle, we show that ex vivo glucocorticoid treatment reduced the expression of proinflammatory genes, confirming that CNF PDEs are a useful model for both mechanistic studies and preclinical drug testing.

Supportive care needs of adults living with a peripherally inserted central catheter (PICC) at home: a qualitative content analysis.

BACKGROUND: Peripherally inserted central catheters (PICCs) are common vascular access devices inserted for adults undergoing intravenous treatment in the community setting. Individuals with a PICC report challenges understanding information and adapting to the device both practically and psychologically at home. There is a lack of research investigating the supportive care needs of individuals with a PICC to inform nursing assessment and the provision of additional supports they may require to successfully adapt to life with a PICC. The aim of this study was to identify the supportive care needs of adults with cancer or infection living with a PICC at home. METHOD: Qualitative, semi-structured interviews were used to identify supportive care needs of adults living with a PICC at home. Participants were recruited from cancer and infectious diseases outpatient units. Two researchers independently analysed transcripts using content analysis. RESULTS: A total of 15 participants were interviewed (30-87 years old). There were 5 males and 10 females interviewed, 9 participants had a cancer diagnosis and most lived in a metropolitan area. Many participants lived with a partner/spouse at home and three participants had young children. Participants identified supportive care needs in the following eight categories (i (i) Adapting daily life (ii) Physical comfort (iii) Self-management (iv) Emotional impact (v) Information content (vi) Understanding information (vii) Healthcare resources and (viii) Social supports. CONCLUSIONS: Adults living with a PICC at home report a broad range of supportive care needs. In addition to practical and information needs, health consumers may also require support to accept living with a device inside their body and to assume responsibility for the PICC. These findings may provide nurses with a greater understanding of individual needs and guide the provision of appropriate supports.

Spatial transcriptomics reveals molecular dysfunction associated with Lewy pathology.

Lewy pathology composed of α-synuclein is the key pathological hallmark of Parkinson's disease (PD), found both in dopaminergic neurons that control motor function, and throughout cortical regions that control cognitive function. Recent work has investigated which dopaminergic neurons are most susceptible to death, but little is known about which neurons are vulnerable to developing Lewy pathology and what molecular changes an aggregate induces. In the current study, we use spatial transcriptomics to selectively capture whole transcriptome signatures from cortical neurons with Lewy pathology compared to those without pathology in the same brains. We find, both in PD and in a mouse model of PD, that there are specific classes of excitatory neurons that are vulnerable to developing Lewy pathology in the cortex. Further, we identify conserved gene expression changes in aggregate-bearing neurons that we designate the Lewy-associated molecular dysfunction from aggregates (LAMDA) signature. This gene signature indicates that neurons with aggregates downregulate synaptic, mitochondrial, ubiquitin-proteasome, endo-lysosomal, and cytoskeletal genes and upregulate DNA repair and complement/cytokine genes. However, beyond DNA repair gene upregulation, we find that neurons also activate apoptotic pathways, suggesting that if DNA repair fails, neurons undergo programmed cell death. Our results identify neurons vulnerable to Lewy pathology in the PD cortex and identify a conserved signature of molecular dysfunction in both mice and humans.

Community-based Intravenous Treatment and Central Venous Access Devices: A Scoping Review of the Consumer and Caregiver Experience, Information Preferences, and Supportive Care Needs.

PURPOSE: Map existing research and describe the consumer/caregiver experience of community-based intravenous treatment, central venous access devices (CVADs), supportive care needs, and information preferences. DESIGN: Scoping review. METHODS: Five databases (Joanna Briggs Institute, Cochrane library, Emcare, Embase, and Medline) were searched. Screening and data extraction were performed independently by two reviewers. FINDINGS: Forty-eight studies were included. CONCLUSIONS: Although community-based intravenous treatment and CVADs have a significant impact on consumers and caregivers, there is scant research on their supportive care needs and information preferences. CLINICAL EVIDENCE: Some consumers and caregivers may require additional support while undergoing community-based intravenous treatment.

Parental Psychological Control and Self-Efficacy as Predictors of Romantic Relationship Power Dynamics.

In the current study, we utilized a person-centered approach to examine the relations of parental psychological control (PPC) and relationship self-efficacy (RSE) to power dynamics in emerging adults' romantic relationships. College student emerging adults (N = 312) completed measures assessing retrospective PPC, RSE, and perceived self and partner power in current relationships. Latent profile analysis uncovered four relationship types based on reported self- and partner-power: balanced-unified, balanced-interchanging, unbalanced-high self, and unbalanced-high partner. Increases in PPC were related to increased odds of being in an unbalanced relationship. Higher levels of RSE were associated with decreased odds of being in an unbalanced relationship. Further, even individuals in the balanced profile who reported average levels of both self and partner power (balanced-interchanging) reported higher levels of PPC and lower levels of RSE compared to those in the balanced group where levels of both self and partner power were low (balanced-unified). These findings suggest using a person-centered approach to relationship power may advance our conceptualization of power distribution in romantic relationships. Further, experienced family dynamics and one's sense of self may be especially important for young adults' tendency to form healthy relationships. The current findings encourage future investigation into the mechanisms by which parental factors predict both dominance and submissiveness in romantic relationships. Understanding predictors of power dynamics may contribute to intimate partner violence prevention and intervention.

Help From a Friend: Helicopter Parenting Predicts Empathy and Bystander Intervention.

Harassment toward others happens in many contexts with a myriad of negative impacts on victims, witnesses, and society. Although preventing harassment of others is ideal, it is also important to consider how bystanders may react in ways to defend the victim and reduce the harassment. Bystanders differ in their reactions to these events and the goal of this investigation is to better understand individual differences in college students' reported tendency to defend victims of harassment. We proposed a mediation model where higher rates of helicopter parenting would predict lower empathic concern and greater personal distress. In turn, lower empathic concern and greater personal distress would predict lower likelihood of defending the victim. College students (n = 305) completed self-report measures of helicopter parenting, empathic concern, personal distress, and bystander intervention to general harassment. Using the Hayes PROCESS program, we found the relation of helicopter parenting to bystander intervention was mediated by empathic concern, such that helicopter parenting predicted lower empathic concern, which predicted lower likelihood of intervening. Helicopter parenting predicted greater personal distress, but personal distress did not predict bystander intervention. In an exploratory analysis, we tested a moderated mediation model in which personal distress moderated the relation of empathic concern to bystander intervention. The moderated mediation model was statistically significant; for students with low to moderate personal distress, empathic concern predicted self-reported intervention. However, for students high in personal distress, empathic concern was not related to self-reported intervention. The current study explained a small amount of the variance in bystander intervention. These findings demonstrate the complex family and personal factors that may explain, to a small degree, individual differences in bystander intervention. Further studies should consider the complex contextual variables that may influence this relationship.

Models of cardiovascular surgery biobanking to facilitate translational research and precision medicine.

Biobanking in health care has evolved over the last few decades from simple biological sample repositories to complex and dynamic units with multi-organizational infrastructure networks and has become an essential tool for modern medical research. Cardiovascular tissue biobanking provides a unique opportunity to utilize cardiac and vascular samples for translational research into heart failure and other related pathologies. Current techniques for diagnosis, classification, and treatment monitoring of cardiac disease relies primarily on interpretation of clinical signs, imaging, and blood biomarkers. Further research at the disease source (i.e. myocardium and blood vessels) has been limited by a relative lack of access to quality human cardiac tissue and the inherent shortcomings of most animal models of heart disease. In this review, we describe a model for cardiovascular tissue biobanking and databasing, and its potential to facilitate basic and translational research. We share techniques to procure endocardial samples from patients with hypertrophic cardiomyopathy, heart failure with reduced ejection fraction, and heart failure with preserved ejection fraction, in addition to aortic disease samples. We discuss some of the issues with respect to data collection, privacy, biobank consent, and the governance of tissue biobanking. The development of tissue biobanks as described here has significant scope to improve and facilitate translational research in multi-omic fields such as genomics, transcriptomics, proteomics, and metabolomics. This research heralds an era of precision medicine, in which patients with cardiovascular pathology can be provided with optimized and personalized medical care for the treatment of their individual phenotype.

Transcatheter Aortic Valve Implantation (TAVI) Versus Surgical Aortic Valve Replacement for Aortic Stenosis (SAVR): A Cost-Comparison Study.

BACKGROUND: Comparative costing studies using real-world data stratified by patient case-mix, are valuable to decision makers for making reimbursement decisions of new interventions. This study evaluated real-world hospital admissions and short-term costs of transcatheter aortic valve implantation (TAVI) and isolated surgical aortic valve replacement (SAVR) for patients with aortic stenosis, stratified by the Society of Thoracic Surgeons (STS) risk scores. METHODS: Retrospective analysis of consecutive patients with a principal diagnosis of aortic stenosis who underwent isolated valve replacement at a single tertiary hospital, January 2012-December 2017. Patients were followed-up for 30 days post-procedure or until hospital discharge if index hospitalisation was greater than 30 days. Intensive care unit (ICU) and hospital length of stay (days), and costs in 2018 Australian dollars for the index procedure and 30-day follow-up were assessed. Multivariable generalised linear and two-part models with gamma distribution and log link function adjusting for Society of Thoracic Surgeons (STS) risk group and key sociodemographic characteristics were used. RESULTS: Of 488 patients, 61% males, median age 78 years (IQR 14 years), 221 (45%) received transcatheter aortic valve replacement (TAVI) and 267 (55%) received surgical aortic valve replacement (SAVR). STS risk scores were low (28%), intermediate (46%) and high (26%) for TAVI patients, and low (85%), intermediate (12%) and high (3%) for SAVR patients. When adjusted, TAVI length of stay was 57% shorter than SAVR (95% CI 31-83%, p<0.001) for intensive care unit (ICU) admission, and 64% shorter (95% CI 47-81%, p<0.001) for hospital admissions. TAVI costs were 13% lower than SAVR (95% CI 4-22%, p=0.005). CONCLUSION: This data suggests short-term health care costs are lower for patients with aortic stenosis undergoing TAVI than SAVR. A further roll-out of the TAVI program in hospitals across Australia may result in savings to the health system.

Adverse events associated with home blood transfusion: A retrospective cohort study.

AIMS AND OBJECTIVES: To determine the rate of individual and system adverse events associated with blood transfusion at home. BACKGROUND: Home or residential care facility based blood transfusion is beneficial for individuals requiring transfusion due to reduced disruption to daily life and the comfort of a familiar environment. However, blood transfusion may result in serious adverse events. There is a lack of research in this area, and there is a need to identify rates of adverse events and evaluate the system used for this service. DESIGN: Retrospective cohort study. METHODS: Existing data routinely collected for clinical care were used to determine client and system adverse events of medically stable adults with a chronic disease who underwent blood transfusion in a home setting provided by a nurse-led service. A STROBE EQUATOR checklist was used for this study (see Appendix S1). RESULTS: There were 1790 episodes of care involving 533 participants, with 13 cases of transfusion reaction (incident rate [IR] 0.7%; 95% CI 0.43-1.25). Only five of these were severe, resulting in the cessation of the blood transfusion and further medical review or hospital admission (IR 0.28%; 95% CI 0.12-0.68). There were no cases of tampered blood packaging, expired or visually damaged blood products. There were 10 cases of incorrect paperwork (0.6%) and nine cases of incorrect temperature (0.5%). There were 153 cases of vascular access device adverse events (IR 8.5% 95% CI 7.3-9.9), most commonly, difficulty cannulating the individual (n = 82, 54%). CONCLUSIONS: A nurse-led home blood transfusion service was associated with low rates of both individual and system adverse events. Further research is needed to explore the perception of those using this service and supports required to improve the experience. RELEVANCE TO CLINICAL PRACTICE: Blood transfusions may be associated with increased risk of morbidity and mortality. This risk may be increased in a home setting due to the distance from an acute care facility. This study has demonstrated that a nurse-led home blood transfusion service is safe (<1% adverse event rate) for those with a medically stable, chronic condition. There were few failures in the system used to provide this service. Adverse events associated with the vascular access device were the most common complication and the reason for most blood product wastage. Mainly, this was due to difficulty inserting the short-term peripheral intravenous catheter (PIVC). RNs should consider ultrasound to aid PIVC insertion to facilitate treatment provision and enhance the experience of the individual.

Parental Warmth and Interpersonal Empathy as Predictors of Sexual Assault Bystander Intervention Efficacy.

Sexual victimization rates of women in the United States remain worryingly high. Much research has focused on the reduction of sexual violence with varying levels of success. One promising avenue of sexual violence reduction research provides evidence that bystanders who intervene appropriately can effectively contribute to a reduction in sexual assault. The Ecological Model for Bystander Intervention provides a conceptual framework for investigating what motivates and what inhibits bystanders. Empirical evidence on various levels of the model has been garnered; however, little is known about the association between particular developmental variables and bystander intervention efficacy situated in the microsystem. The goal of this study was to explore developmental predictors of bystander intervention efficacy. We predicted perceived parental warmth would be related to bystander intervention efficacy and that the relation would be mediated by empathy. University students (mean age = 19.2 years) completed anonymous online self-report measures of perceived maternal and paternal warmth, empathy, and bystander efficacy. The mediation model was supported by the data. As predicted, the path from parental warmth to empathy was significant (p < .001) and the path from empathy to bystander intervention efficacy was significant (p < .001). The indirect effect of parental warmth on bystander efficacy through empathy was significant (p = .001). One implication of these findings is that characteristics that are related to bystander tendencies may develop early in the family environment. Efforts to increase bystander intervention may benefit from the recognition that empathy may be founded in earlier life experiences. Limitations and future directions are discussed.

Generation and Characterization of Mouse Models for Skeletal Disease.

Our laboratories have used genetically engineered mouse models (GEMMs) to assess genetic contributions to skeletal diseases such as osteoporosis and osteoarthritis. Studies on the genetic contributions to OA are often done by assessing how GEMMs respond to surgical methods that induce symptoms modeling OA. Here, we will describe protocols outlining the induction of experimental OA in mice as well as detailed descriptions of methods for analyzing skeletal phenotypes using micro-computerized tomography and skeletal histomorphometry.

Helicopter Parenting, Authenticity, and Depressive Symptoms: A Mediation Model.

Helicopter parenting is an overinvolved, overcontrolling parenting style that likely interferes with children's healthy development of authenticity. Authenticity refers to self-awareness and a genuine expression of the self and is important for college students as they traverse the opportunities and challenges of emerging adulthood. Authenticity appears to be a protective characteristic and is negatively related to depressive symptoms. The authors proposed and tested a model in which helicopter parenting was related to depressive symptoms through authenticity. In the present investigation, college students (n = 286) completed self-report instruments assessing perceptions of helicopter parenting, current states of authenticity (self-alienation, authentic living, external influence), and depressive symptoms. Path analysis was conducted with AMOS, and the data fit the model well (χ2(1) = .580, p = .446, TLI = 1.103, CFI = 1.000, RMSEA = .000). Helicopter parenting was related to higher levels of self-alienation and external influence and lower levels of authentic living. Self-alienation and authentic living were related to depressive symptoms (external influence was not related to depressive symptoms). These findings demonstrate the importance of considering developmental predictors of authenticity and depression. Helicopter parenting is likely to inhibit authenticity in ways that may contribute to difficulties in emerging adulthood.

Kinome Profiling of NF1-Related MPNSTs in Response to Kinase Inhibition and Doxorubicin Reveals Therapeutic Vulnerabilities.

Neurofibromatosis Type 1 (NF1)-related Malignant Peripheral Nerve Sheath Tumors (MPNST) are highly resistant sarcomas that account for significant mortality. The mechanisms of therapy resistance are not well-understood in MPNSTs, particularly with respect to kinase inhibition strategies. In this study, we aimed to quantify the impact of both the genomic context and targeted therapy on MPNST resistance using reverse phase phosphoproteome array (RPPA) analysis. We treated tumorgrafts from three genetically engineered mouse models using MET (capmatinib) and MEK (trametinib) inhibitors and doxorubicin, and assessed phosphosignaling at 4 h, 2 days, and 21 days. Baseline kinase signaling in our mouse models recapitulated an MET-addicted state (NF1-MET), P53 mutation (NF1-P53), and HGF overexpression (NF1). Following perturbation with the drug, we observed broad and redundant kinome adaptations that extended well beyond canonical RAS/ERK or PI3K/AKT/mTOR signaling. MET and MEK inhibition were both associated with an initial inflammatory response mediated by kinases in the JAK/STAT pathway and NFkB. Growth signaling predominated at the 2-day and 21-day time points as a result of broad RTK and intracellular kinase activation. Interestingly, AXL and NFkB were strongly activated at the 2-day and 21-day time points, and tightly correlated, regardless of the treatment type or genomic context. The degree of kinome adaptation observed in innately resistant tumors was significantly less than the surviving fractions of responsive tumors that exhibited a latency period before reinitiating growth. Lastly, doxorubicin resistance was associated with kinome adaptations that strongly favored growth and survival signaling. These observations confirm that MPNSTs are capable of profound signaling plasticity in the face of kinase inhibition or DNA damaging agent administration. It is possible that by targeting AXL or NFkB, therapy resistance can be mitigated.

Emergency Medicine Residency Applicant Characteristics Associated with Measured Adverse Outcomes During Residency.

INTRODUCTION: Negative outcomes in emergency medicine (EM) programs use a disproportionate amount of educational resources to the detriment of other residents. We sought to determine if any applicant characteristics identifiable during the selection process are associated with negative outcomes during residency. METHODS: Primary analysis consisted of looking at the association of each of the descriptors including resident characteristics and events during residency with a composite measure of negative outcomes. Components of the negative outcome composite were any formal remediation, failure to complete residency, or extension of residency. RESULTS: From a dataset of 260 residents who completed their residency over a 19-year period, 26 (10%) were osteopaths and 33 (13%) were international medical school graduates A leave of absence during medical school (p <.001), failure to send a thank-you note (p=.008), a failing score on United States Medical Licensing Examination Step I (p=.002), and a prior career in health (p=.034) were factors associated with greater likelihood of a negative outcome. All four residents with a "red flag" during their medicine clerkships experienced a negative outcome (p <.001). CONCLUSION: "Red flags" during EM clerkships, a leave of absence during medical school for any reason and failure to send post-interview thank-you notes may be associated with negative outcomes during an EM residency.

Non-amyloidogenic effects of α2 adrenergic agonists: implications for brimonidine-mediated neuroprotection.

The amyloid beta (Aß) pathway is strongly implicated in neurodegenerative conditions such as Alzheimer's disease and more recently, glaucoma. Here, we identify the α2 adrenergic receptor agonists (α2ARA) used to lower intraocular pressure can prevent retinal ganglion cell (RGC) death via the non-amyloidogenic Aß-pathway. Neuroprotective effects were confirmed in vivo and in vitro in different glaucoma-related models using α2ARAs brimonidine (BMD), clonidine (Clo) and dexmedetomidine. α2ARA treatment significantly reduced RGC apoptosis in experimental-glaucoma models by 97.7% and 92.8% (BMD, P<0.01) and 98% and 92.3% (Clo, P<0.01)) at 3 and 8 weeks, respectively. A reduction was seen in an experimental Aß-induced neurotoxicity model (67% BMD and 88.6% Clo, both P<0.01, respectively), and in vitro, where α2ARAs significantly (P<0.05) prevented cell death, under both hypoxic (CoCl2) and stress (UV) conditions. In experimental-glaucoma, BMD induced ninefold and 25-fold and 36-fold and fourfold reductions in Aß and amyloid precursor protein (APP) levels at 3 and 8 weeks, respectively, in the RGC layer, with similar results with Clo, and in vitro with all three α2ARAs. BMD significantly increased soluble APPα (sAPPα) levels at 3 and 8 weeks (2.1 and 1.6-fold) in vivo and in vitro with the CoCl2 and UV-light insults. Furthermore, treatment of UV-insulted cells with an sAPPα antibody significantly reduced cell viability compared with BMD-treated control (52%), co-treatment (33%) and untreated control (27%). Finally, we show that α2ARAs modulate levels of laminin and MMP-9 in RGCs, potentially linked to changes in Aß through APP processing. Together, these results provide new evidence that α2ARAs are neuroprotective through their effects on the Aß pathway and sAPPα, which to our knowledge, is the first description. Studies have identified the need for α-secretase activators and sAPPα-mimetics in neurodegeneration; α2ARAs, already clinically available, present a promising therapy, with applications not only to reducing RGC death in glaucoma but also other neurodegenerative processes involving Aß.

Lurbinectedin Inactivates the Ewing Sarcoma Oncoprotein EWS-FLI1 by Redistributing It within the Nucleus.

There is a great need to develop novel approaches to target oncogenic transcription factors with small molecules. Ewing sarcoma is emblematic of this need, as it depends on the continued activity of the EWS-FLI1 transcription factor to maintain the malignant phenotype. We have previously shown that the small molecule trabectedin interferes with EWS-FLI1. Here, we report important mechanistic advances and a second-generation inhibitor to provide insight into the therapeutic targeting of EWS-FLI1. We discovered that trabectedin functionally inactivated EWS-FLI1 by redistributing the protein within the nucleus to the nucleolus. This effect was rooted in the wild-type functions of the EWSR1, compromising the N-terminal half of the chimeric oncoprotein, which is known to be similarly redistributed within the nucleus in the presence of UV light damage. A second-generation trabectedin analogue lurbinectedin (PM01183) caused the same nuclear redistribution of EWS-FLI1, leading to a loss of activity at the promoter, mRNA, and protein levels of expression. Tumor xenograft studies confirmed this effect, and it was increased in combination with irinotecan, leading to tumor regression and replacement of Ewing sarcoma cells with benign fat cells. The net result of combined lurbinectedin and irinotecan treatment was a complete reversal of EWS-FLI1 activity and elimination of established tumors in 30% to 70% of mice after only 11 days of therapy. Our results illustrate the preclinical safety and efficacy of a disease-specific therapy targeting the central oncogenic driver in Ewing sarcoma. Cancer Res; 76(22); 6657-68. ©2016 AACR.

Targeting MET and EGFR crosstalk signaling in triple-negative breast cancers.

There is a vital need for improved therapeutic strategies that are effective in both primary and metastatic triple-negative breast cancer (TNBC). Current treatment options for TNBC patients are restricted to chemotherapy; however tyrosine kinases are promising druggable targets due to their high expression in multiple TNBC subtypes. Since coexpression of receptor tyrosine kinases (RTKs) can promote signaling crosstalk and cell survival in the presence of kinase inhibitors, it is likely that multiple RTKs will need to be inhibited to enhance therapeutic benefit and prevent resistance. The MET and EGFR receptors are actionable targets due to their high expression in TNBC; however crosstalk between MET and EGFR has been implicated in therapeutic resistance to single agent use of MET or EGFR inhibitors in several cancer types. Therefore it is likely that dual inhibition of MET and EGFR is required to prevent crosstalk signaling and acquired resistance. In this study, we evaluated the heterogeneity of MET and EGFR expression and activation in primary and metastatic TNBC tumorgrafts and determined the efficacy of MET (MGCD265 or crizotinib) and/or EGFR (erlotinib) inhibition against TNBC progression. Here we demonstrate that combined MET and EGFR inhibition with either MGCD265 and erlotinib treatment or crizotinib and erlotinib treatment were highly effective at abrogating tumor growth and significantly decreased the variability in treatment response compared to monotherapy. These results advance our understanding of the RTK signaling architecture in TNBC and demonstrate that combined MET and EGFR inhibition may be a promising therapeutic strategy for TNBC patients.