Objectives/Goals: Motivational deficits are associated with depression and poorly treated by current therapeutics. We sought to identify more effective therapeutics for these deficits using a mouse model of early-life exposure to SSRIs, a developmental risk factor identified for depression in humans. Methods/Study Population: Mice were administered the SSRI, fluoxetine (FLX), or a vehicle control from postnatal day P2-P11, a window that mimics brain development occurring during the third trimester in a human pregnancy. Motivation and hedonic perception were assessed in adulthood using the progressive ratio and lickometer tasks, respectively. Behavioral testing was repeated after chronic adult administration of either an SSRI (fluoxetine), an atypical antidepressant and mu-opioid receptor agonist (tianeptine), or a mu-opioid receptor antagonist (methocinnamox). Results/Anticipated Results: Mice administered FLX in early-life showed motivational deficits in the progressive ratio task, while hedonic perception, as measured by the lickometer task, remained intact. Chronic administration of FLX in adulthood did not improve motivational deficits and did not alter hedonic perception. Chronic administration of tianeptine (TIA) slightly improved motivational behavior without altering hedonic perception. In contrast, chronic administration of the mu opioid antagonist methocinnamox (MCAM) markedly improved motivational deficits in mice, even while blunting hedonic perception. The ability of MCAM to enhance motivation was selective to early-FLX exposed mice Discussion/Significance of Impact: Our results reveal that unexpectedly opioid receptor antagonism is effective at improving motivation in mice exposed to SSRIs in early life. This suggests potential novel treatment approaches in individuals with motivational impairments and a history of in utero exposure to SSRIs.

Preparing investigators to competently conduct community-engaged research is critical to achieving Clinical and Translational Science Award (CTSA) program goals. The purpose of this study is to describe the perspectives of members of a long-standing community engagement advisory board (CEAB) on investigators’ readiness to engage communities and indicators of investigator competence in community-engaged research, in order to suggest core competencies to guide the development of CTSA-sponsored educational programs. Two 90-minute focus groups were conducted with a subset of members of a CEAB (n=19) affiliated with the Center for Clinical and Translational Science at the University of Illinois at Chicago. CEAB members identified a range of investigator skills and practices that demonstrate readiness to engage in community-engaged research. Eight competencies were identified that should be incorporated in providing education to enhance the readiness and competency of CTSA-affiliated researchers planning to engage communities in research. CEAB observations demonstrate the necessity of developing competency-based educational programs that prepare clinical and translational scientists at all levels for the important work of community-engaged research.

Single institutional review board (IRB) review of multisite research increased in frequency over a decade ago with a proliferation of master IRB reliance agreements supporting statewide and regional consortia and disease- and population-specific networks. Although successful, the increasing number of agreements presented significant challenges and illuminated potential benefits of a single, nationwide agreement. Anticipated changes in federal regulations highlighted the need to systematize and simplify IRB reliance. To address these challenges, the NIH National Center for Advancing Translational Sciences funded a project to establish a national IRB reliance network that would support national adoption of single IRB (sIRB) review. The Streamlined, Multisite, Accelerated Resources for Trials (SMART) IRB Platform launched in July 2016 to facilitate dissemination, adoption, and implementation of a collaboratively developed master IRB reliance agreement and supportive tools and resources. More than 580 institutions have joined SMART IRB’s Master Common Reciprocal Institutional Review Board Authorization Agreement and begun using the SMART IRB platform to support sIRB arrangements. Here, we describe the tenets of the agreement and operational benefits and challenges of its use. SMART IRB’s early success affirms the utility of collaborative, flexible, and centralized approaches to supporting sIRB review while highlighting the need for further national harmonization.

Engaging diverse partners in each phase of the research process is the gold standard of community-engaged research and adds value to the impact of implementation science. However, partner engagement in dissemination, particularly meaningful involvement in developing peer-reviewed manuscripts, is lacking. The Implementation Science Centers in Cancer Control are using the Translational Science Benefits Model to demonstrate the impact of our work beyond traditional metrics, including building capacity and promoting community engagement. This paper presents a case example of one center that has developed a policy for including community partners as coauthors. Standard practices are used to foster clear communications and bidirectional collaboration. Of published papers focused on center infrastructure and implementation research pilots, 92% have community partner coauthors. This includes 21 individuals in roles ranging from physician assistant to medical director to quality manager. Through this intentional experience of co-creation, community partners have strengthened implementation science expertise. Community coauthors have also ensured that data interpretation and dissemination reflect real-world practice environments and offer sustainable strategies for rapid translation to practice improvements. Funders, academic journals, and researchers all have important roles to play in supporting community coauthors as critical thought partners who can help to narrow the gap between research and practice.

Contactless photoplethysmography (cPPG) is a method of physiological monitoring. It differs from conventional monitoring methods (e.g., saturation probe) by ensuring no contact with the subject by use of a camera. The majority of research on cPPG is conducted in a laboratory setting or in healthy populations. This review aims to evaluate the current literature on monitoring using cPPG in adults within a clinical setting. Adhering to the Preferred Items for Systematic Reviews and Meta-analysis (PRISMA, 2020) guidelines, OVID, Webofscience, Cochrane library, and clinicaltrials.org were systematically searched by two researchers. Research articles using cPPG for monitoring purposes in adults within a clinical setting were selected. Twelve studies with a total of 654 individuals were included. Heart rate (HR) was the most investigated vital sign (n = 8) followed by respiratory rate ((n = 2), Sp02 (n = 2), and HR variability (n = 2). Four studies were included in a meta-analysis of HR compared to ECG data which demonstrated a mean bias of –0.13 (95% CI, –1.22–0.96). This study demonstrates cPPG can be a useful tool in the remote monitoring of patients and has demonstrated accuracy for HR. However, further research is needed into the clinical applications of this method.

Clinical trial participation among historically underrepresented populations remains low in large part due to mistrust of academic institutions and research investigators. Mistrust may be ever greater today given misinformation related to COVID-19. The Research Ambassador Program is an interactive educational workshop delivered by Promotoras de Salud/Community Health Workers and designed to both address common myths, fears, and concerns about research and encourage research participation among underrepresented populations. An evaluation conducted with 819 Latino and Black participants demonstrated a change in behavior and intention to participate in a clinical trial, with half of participants enrolling in a clinical trial research registry.

Objectives/Goals: The goal of this study is to determine the function of the rete ovarii (RO), an uncharacterized secretory epithelial appendage to the ovary. I am testing the hypothesis that the RO is critical for the maintenance of the ovarian reserve and fertility, and progesterone signaling plays a role in the function of the RO. Methods/Study Population: For this project, I am utilizing a mouse model. To visualize the rete ovarii (RO) in vivo, I am using a Pax8rtTA; TRE-H2B-Gfp (PTG) reporter mouse, which expresses green fluorescent protein in the RO. To determine the role of the RO in fertility and maintenance of the ovarian reserve, I will surgically ablate the RO or perform a sham surgery on adult female PTG mice. Then, I will follow-up with quantification of the ovarian reserve and long-term fertility tracking studies. To determine how the RO responds to progesterone, the RO will be cultured ex vivo in the presence and absence of progesterone. I will perform a morphometric analysis of the RO, as well as collect secreted proteins from the media for proteomic analysis. Results/Anticipated Results: If the RO is important for ovarian homeostasis, I expect that in the absence of the RO, ovarian functions such as maintenance of the ovarian reserve and fertility will be impaired. Additionally, because the RO expresses progesterone receptors, I anticipate that the RO will be responsive to progesterone as shown in changes in the morphometric analysis and in changes in secreted proteins in the presence of progesterone. Discussion/Significance of Impact: A major gap in knowledge regarding female physiology and reproductive health is the role of the RO. We expect this work to reveal that progesterone signaling in the RO is important for regulating ovarian functions and to show that the RO is a critical modulator of female fertility and reproductive function.

OBJECTIVES/SPECIFIC AIMS: To complete a needs assessment and action planning process that engaged clinical and translational research network members in identifying needs through survey feedback, characterizing the needs in small group sessions, and developing recommendations for action at the network’s annual scientific meeting. METHODS/STUDY POPULATION: The project included (1) a survey of 357 members across partner institutions from the Great Plains IDeA CTR Network, (2) 6 - 90 minute brainstorming sessions to characterize needs identified through survey assessment, and (3) 6 - 60 minute sessions to develop recommendations for network improvement based on the characterization activity. Approximately 75 members participated in the characterization and recommendation sessions. RESULTS/ANTICIPATED RESULTS: Seven areas of need from the survey were identified based upon the frequency of identification by network members (support to move research across the translational spectrum, database design and management, data access and sharing, data analysis, recruitment and retention of subjects, support for members who have submitted grants but were repeatedly unsuccessful, mentoring). Members indicated which characterization sessions they were interested in attending and based on the enrollment numbers needs related to unsuccessful grant submitters and mentoring were combined as were needs related to database design and data access-sharing. Sessions resulted in 8 inter-related recommendations for network action that included to (1) develop GP-CTR directory/registry of clinicians, researchers, system partners, that can be used to identify people that want to be involved in research partnerships or mentoring, (2) create a GP CTR Navigators Program to will provide support to network members throughout the collaborative research and grant preparation process, (3) identify and disseminate information about assets (funding, databases/registries) that exist amongst network partners that can be leveraged by member, (4) develop a searchable repository of evidence-based interventions for T3/T4 efforts, (5) review GP CTR supported professional development, and technological resource offerings and identify potential gaps, (6) facilitate opportunities for peer support/networking, (7) provide guidance to GP CTR network institutions looking to adopt policies that will support translational research collaboration, and (8) identify potential barriers to GP CTR network engagement (i.e., infrastructure, communication, marketing). DISCUSSION/SIGNIFICANCE OF IMPACT: This process allowed for a wide range of network members to contribute to actionable recommendations for CTR leadership to move into action and improve the scientific network’s ability to conduct clinical and translational research.

ABSTRACT IMPACT: Successful implementation of this control strategy will result in a commercially available ivermectin-treated birdfeed that the public can use to protect themselves from infection with West Nile virus (WNV) by reducing mosquito survival and thereby suppressing WNV transmission around their homes. OBJECTIVES/GOALS: We assessed the efficacy and feasibility of ivermectin (IVM)-treated birds as a mosquito control strategy for local reduction of West Nile virus (WNV) transmission. We conducted a randomized field trial in backyard chickens and developed a mathematical model informed by field data to predict the impact of treated wild birds on transmission. METHODS/STUDY POPULATION: We placed 48 chickens in four treated and four untreated control flocks in backyards coops across Davis, CA and administered IVM daily in feed to treated flocks (Jul-Sep 2019). We assessed entomological indices weekly (i.e. Culex mosquito abundance, WNV infection prevalence, and parity rate) around each coop, monitored serum IVM levels in treated chickens, and tested for WNV antibodies in all chickens. Shifting our focus to wild birds, we developed a spatially-implicit mathematical model of WNV transmission near IVM-treated birdfeeders. Model parameters for bird movement were based on our telemetry of 27 birds in Fort Collins, CO (Aug-Sep 2020). Using the model, we predicted optimal deployment of treated feeders to provide local WNV control. RESULTS/ANTICIPATED RESULTS: WNV seroconversions were reduced in treated vs. untreated flocks, indicating a reduction in WNV transmission intensity at treated coops (P = 0.03). A sustained, but insignificant reduction in number of infected mosquitoes was observed near treated coops (P = 0.59); small sample sizes and below normal WNV prevalence in the study area limited our power. We anticipate that optimal spacing and number of IVM-treated birdfeeders required for effective WNV control in neighborhoods will depend on feeder usage rates by common bird species irrespective of WNV competence; broad availability of IVM-treated bloodmeals to mosquitoes will be more effective in reducing transmission than targeting the few species responsible for viral amplification. DISCUSSION/SIGNIFICANCE OF FINDINGS: IVM is a novel method for controlling zoonotic pathogens in the US and has the potential for targeted mosquito control to reduce pesticide usage. Evaluating spatial deployment of IVM-treated bird feed for local reduction in WNV transmission is a stepping stone to commercial deployment of this WNV control strategy.

OBJECTIVES/GOALS: Acidity and the lactate-to-pyruvate ratio correlate with immunotherapy resistance. AcidoCEST MRI and hyperpolarized magnetic resonance spectroscopy (HP-MRS) measure extracellular pH and lactate-to-pyruvate ratio. We will establish a baseline for these biomarkers then observe changes after combination esomeprazole and immunotherapy. METHODS/STUDY POPULATION: We used multiple melanoma models created via serial in vivo passage under immunotherapeutic pressure (FVAX, CTLA-4, PD-1, PD-L1). We used four of these corresponding to 25%, 50%, 75% and 100% resistance (TMT, F2, F3, and F4, respectively). HP-MRS was performed two weeks post implantation in male BL6 mice with AcidoCEST MRI 2-3 days later. Tumors were implanted in additional mice and grown for 1 week. We used esomeprazole as a possible immunotherapy sensitizer. Esomeprazole (or PBS) alone and in combination with immune checkpoint blockade (ICB; αCTLA-4, αPD-1) was then conducted every 3 days for 3 doses. ICB was administered 3h after esomeprazole. AcidoCEST MRI was performed the day after the final dose of combination therapy and 3h after esomeprazole (or PBS) alone. HP-MRS was performed 2-3 days after acidoCEST MRI. RESULTS/ANTICIPATED RESULTS: There was a statistical increase in the lactate-to-pyruvate ratio of the F4 group compared with TMT, F2, and F3 groups (p < 0.05). The TMT, F2, and F3 groups did not differ significantly. The extracellular pH (pHe) of the TMT group was statistically lower than the F2 and F4 groups (p < 0.05). The pHe did not differ significantly between the TMT and F3 groups nor the F2, F3, and F4 groups. The lactate-to-pyruvate ratio and pHe after combination treatment with esomeprazole and ICB did not differ compared to PBS+ICB control. Treatment with esomeprazole alone generated higher lactate-to-pyruvate ratio compared with PBS alone. Tumor volume curves and survival curves of mice bearing F4 tumors treated with esomeprazole combination with ICB showed no difference compared with PBS+ICB, PBS alone, and esomeprazole alone. DISCUSSION/SIGNIFICANCE: We differentiated between the 100% and 25% resistant models with both pHe and lactate-to-pyruvate ratio, although the pHe was counterintuitive. Esomeprazole was ineffective, but other potential sensitizers exist. A non-invasive clinical imaging tool and sensitizer would permit more personalized treatment plans so treatment is more effective.

OBJECTIVES/GOALS: Platelets reside at the nexus of thrombosis and inflammation which make them an ideal target of investigation to understand mechanisms underlying chronic kidney disease (CKD)-related inflammatory and thrombotic dysregulation. Our objective is to determine whether a pro-inflammatory state in CKD is exacerbated by platelets. METHODS/STUDY POPULATION: Aim 1 will investigate effects of engineered reduction in the interaction of platelets with leukocytes [by disruption of one of the platelet surface receptor (GPIb-IX)] in the development of CKD in murine models. Aim 2 will investigate effects of platelet inhibitors on the development of CKD in murine models. RESULTS/ANTICIPATED RESULTS: We anticipate that the proposed studies in Aim 1 will demonstrate reduction in the interaction of platelets with leukocytes results in exacerbation of kidney injury upon CKD induction with cisplatin. We also anticipate that inhibition of platelets in Aim 2 with P2Y12 receptor inhibitors results in reduction in kidney injury upon CKD induction with cisplatin. DISCUSSION/SIGNIFICANCE: Upon successful completion of the proposed studies, we shall be able to better describe the role of platelets as modulators of inflammation in CKD. This will be a significant stride towards understanding the pathophysiology of a pro-inflammatory state in CKD and how platelets exacerbate inflammation and thrombosis in this population.

OBJECTIVES/GOALS: There are gain-of-function genomic alterations in FGFR genes that guide personalized treatment in some patients with cholangiocarcinoma (10%) and bladder cancer (30%) who can benefit from targeted therapies. We sought to evaluate other genomic alterations in cancer involving FGFRs and assess whether they are gain-of-function. METHODS/STUDY POPULATION: We collaborated with Foundation Medicine Inc (FMI), for the assessment of 300,000 sequenced tumors and a retrospective analysis of recent publications, to identify novel candidate FGFR alterations. We propose to transiently transfect HEK293T cells with an empty vector (EV), FGFR1-4 wild-type (WT), and these variants and use a luminescent-proximity based high-throughput assay, AlphaLISA, and Western blot to assess FGFR and phosphorylated downstream signaling proteins, FRS2, AKT and ERK, and their sensitivity to FGFR inhibitors: pemigatinib, erdafitinib, futibatinib, RLY-4008, and TYRA-200. RESULTS/ANTICIPATED RESULTS: Through our collaboration we identified >100 novel candidate FGFR1-4 variants of unknown significance (VUS) including extracellular-in-frame deletions (EIDs), kinase domain duplications (KDDs), insertions/deletions (INDELs), short number variants (SNVs), and truncations. Immunoblot analysis confirmed the presence of desired EV, FGFR WT, and VUS’ in HEK293T cells. We anticipate the FGFR EIDs and KDDs to display an increased presence of in the respective pFGFR, pFRS2, pERK, and pAKT as compared to the EV and FGFR WT by both immunoblot and AlpahLISA analysis. Additionally, we anticipate the VUS’ to be sensitive to FGFR inhibitors: pemigatinib, erdafitinib, futibatinib, RLY-4008, and TYRA-200 using the AlphaLISA assay. DISCUSSION/SIGNIFICANCE: These findings suggest that the novel FGFR VUS’ are capable of constitutive activation of FGFR kinase activity, and they preliminary demonstrate that these newly identified FGFR alterations are therapeutically targetable. Thus, providing rationale for further clinical evaluation to identify new cohorts of FGFR inhibitor responders.

OBJECTIVES/GOALS: This report evaluates participants’experiences from three universities who assembled a complex grant proposal related to research on post-acute sequala of COVID-19 (PASC), also called long COVID. Activities reviewed ranged from the assembly of the team to responses to reviews by the National Center for Advancing Translational Sciences (NCATS). METHODS/STUDY POPULATION: Data were collected by means of semi-structured interviews, conducted and recorded on Zoom, with a sample of 15 scientists and staff both during proposal assembly and following proposal review. The sample comprised 40% of the total team equally selected from the 3 universities, The interview protocol was reviewed by the IRB at UTMB and the interviews were recorded on Zoom, and analyzed by means of the constant comparative strategy in the grounded theory method of qualitative research. Given the relatively small number of interviews in this project, we paid special attention to preserving the confidentiality of respondents. Only the verbal tracks of the interviews were professionally transcribed. Respondents were asked to suggest changes for future inter-organizational proposals. RESULTS/ANTICIPATED RESULTS: FIRST INTERVIEWS *LEADERSHIP: The scope of leadership opportunities was expanded as sub-teams in specific areas such as community engagement were formed. *TEAM: Each university’s community engagement team specializes in a different ethnic clientele, precluding a singular statement for the proposal. SECOND INTERVIEWS *LEADERSHIP: Staff members noted that the team concept too easily evolved into a bureaucratic format, resulting in less negotiation and more direction. *ASSEMBLY TASKS: The Writing Team turned out to be one of the most critical staff teams. *COMMUNICATION: The behavioral scientists in community engagement do not necessarily share paradigms (e.g., public health, psychology, and social work). They had difficulty generating productive communication and a unified statement for the proposal. DISCUSSION/SIGNIFICANCE: The scientists, as a group, suggested that future proposals should focus on one general topic, such as the microbiome, as opposed to attempting to integrate widely divergent interests. The scientists as a group should decide a priori whether to treat innovative ideas such as machine learning science as a science or a service.

Objectives/Goals: Our research addresses critical gaps by examining the prevalence, blood concentrations, and health implications of xylazine abuse, with a focus on its cardiotoxic effects. We aim to map the geographic distribution of xylazine use across Puerto Rico and characterize its impact on cardiomyocytes at relevant exposure levels. Methods/Study Population: To accurately detect and quantify xylazine in blood samples, we will employ chromatographic techniques coupled with mass spectrometry (UPLC/MS or GC/MS). The xylazine prevalence across the island will be mapped based on health system classifications. Samples will be categorized according to the eight healthcare regions of Puerto Rico, as defined by the “Administración de Seguros de Salud” (ASES), ensuring comprehensive geographic representation. We will investigate the expression profiles of proteins associated with cardiac injury and dysfunction in human cardiomyocytes and in the blood of drug users. Blood samples will be provided by “Iniciativa Comunitaria.” We will assess the xylazine effects on human cardiomyocyte viability and identify key biomarkers of cardiotoxicity induced by xylazine exposure. Results/Anticipated Results: In previous research, we demonstrated that xylazine induces cell death in endothelial cells through both extrinsic and intrinsic pathways. We also observed an increase in reactive oxygen species (ROS) levels after drug exposure, indicating oxidative stress as a potential mechanism of toxicity. Additionally, DNA damage was detected. Given the known relationship between endothelial damage and cardiomyocyte dysfunction in drug-induced cardiotoxicity, we hypothesize that xylazine concentrations vary regionally within Puerto Rico and that chronic xylazine abuse will elevate markers of cardiac injury and dysfunction at common user doses. Discussion/Significance of Impact: The increasing xylazine abuse, particularly in Puerto Rico, represents a critical public health challenge. Our study will fill a knowledge gap by providing crucial data on xylazine’s cardiotoxicity and mapping its geographic prevalence, with the potential to advise healthcare approaches and improve care for drug-using Hispanic populations.

OBJECTIVES/GOALS: The goal of the study is to understand how changing the surface roughness of 3D printed Titanium either by processing printed samples or artificially printing rough topography impacts the mechanical and biological properties of the Titanium. METHODS/STUDY POPULATION: Titanium dog bones and discs were printed via laser powder bed fusion. groups were defined as 1. polished, 2.blasted, 4.as built, 4.sprouts and 5.rough sprouts. Roughness was measured with line measurement using a confocal microscope. Tensile testing of dog bones produced stress strain curves. MC3T3 preosteoblast were seeded on discs. Samples were analyzed at 0, 2, and 4 weeks. A cell viability assay and confocal fluorescent microscopy assessed cell growth. Alkaline Phosphatase (ALP) assay and Quantitative Polymerase Chain Reaction (qPCR) examined cell differentiation. Extracellular matrix (ECM) was stained for collagen and calcium. Scanning Electron Microcopy (SEM) was done on sputter coated discs. RESULTS/ANTICIPATED RESULTS: Measured roughness defined by Rz, maximum peak to valley distance of the sample profile ranged from 2.6-65.1 µm. The addition of printed roughness in the sprouts and rough sprouts group significantly diminished ductility resulting in early strain to failure during tensile testing. Cells adhered and proliferated on discs regardless of roughness group. There was no statistical difference in ALP activity, but qPCR showed that rough groups (sprouts and rough sprouts) had diminished Osteocalcin gene expression at week 2 and 4. The ECM in the rough groups was more resistant to repeated washes and was more extensive with SEM. DISCUSSION/SIGNIFICANCE OF IMPACT: Printing roughness diminished mechanical properties without clear benefit to cell growth. Roughness features were on mesoscale, unlike samples in literature on microscale that increase cell activity. Printed topography may aid in implant fixation and not osseous integration as hypothesized. CONFLICT OF INTEREST DESCRIPTION: Dr. Samual Adams, Dr. Ken Gall and Cambre Kelly own stock and/or stock options in restor3d, Inc.

OBJECTIVES/GOALS: Irreproducible and incompletely reported research lead to misallocated resources, wasted effort in pursing inappropriate avenues of investigation, and loss of public trust. To address this challenge, we employed a Team Science approach to create a multi-modal program to support Rigor, Reproducibility, and Reporting in Translational Science. METHODS/STUDY POPULATION: We conducted literature searches to reveal sources of irreproducibility and recommended corrective actions, invited leaders in the field to give lectures on opportunities to support reproducible science, and worked with the Rockefeller team science leadership group to instill an overarching rigor approach, infused into all training efforts. This multifaceted program was labeled R3 (R-cubed) for Enhancing Scientific Rigor, Reproducibility, and Reporting. RESULTS/ANTICIPATED RESULTS: Didactic Courses:

• Introduction to Biostatistics and Critical Thinking – focus on pitfalls in inferential statistics, consequences of poor research, and errors in published research.

• Scientific Writing – teaches methods and procedures in writing to ensure reproducibility. Lecture Series

• Established nine lectures on topics related to R3, including Data Management, Statistical Methods, Genomic Analyses, Data Repositories, Data Sharing, Pharmacy Formulation, and e-lab notebooks. Website

• Creating a comprehensive website as repository for research, methods, programs, updates, and improvements related to R3. KL2 Clinical Scholars Seminars and Navigation

• Scholars participate in seminars and tutorials to discuss opportunities to improve R3 across the research life-course.

DISCUSSION/SIGNIFICANCE OF IMPACT: Striving for research reproducibility takes focused energy, discipline, and vigilance, but the effort is worthwhile as rigorous and reproducible science is the prerequisite for successful translation of great discoveries into improved health. CONFLICT OF INTEREST DESCRIPTION: none

OBJECTIVES/GOALS: Estrogen receptor-positive (ER+) breast cancers (BC) comprise >70% of all BC and cause the most BC-related deaths in women worldwide. Despite available therapies against ER+ BC, recurrence often arises due to development of endocrine therapy resistance. Thus, our goal is to identify novel biomarkers that could serve as therapeutic targets for ER+ BC. METHODS/STUDY POPULATION: We have identified a neuroimmune molecule, Semaphorin 7a (SEMA7A), as a potential biomarker for endocrine therapy resistance, relapse, and poor survival in ER+ BC patients. SEMA7A promotes tumor growth, angiogenesis, epithelial-to-mesenchymal transition, metastasis, and endocrine therapy resistance in our pre-clinical models. Specifically, using in vivo models we have shown that SEMA7A+ MCF7 tumors result in lung metastases that do not respond to fulvestrant, in part via downregulation of ER, posing the need to identify novel, druggable targets for SEMA7A+ ER+ BC patients. SEMA7A is a membrane-bound protein that can inhibit tumor cell death via integrin-mediated PI3K/Akt pro-survival signaling. Thus, we hypothesized that SEMA7A+ ER+ BC may be sensitive to PI3K inhibition in combination with fulvestrant. RESULTS/ANTICIPATED RESULTS: Our preliminary studies confirmed that high SEMA7A expression associates with increased phospho-Akt levels and decreased apoptosis of tumor cells in forced suspension conditions. We also observed that human MCF7 ER+ SEMA7A overexpressing (OE) cells are sensitive to the PI3K (P110ï ¡ï€©ï€ inhibitor, Alpelisib. Also, the combination of Alpelisib with fulvestrant inhibited tumor cell viability in MCF7 cells, which was further enhanced in the SEMA7A OE counterparts. The combination also decreased proliferation and tumor sphere formation. There are currently no therapies that directly target SEMA7A, and here I propose an innovative hypothesis that PI3K inhibition will block SEMA7A signaling. DISCUSSION/SIGNIFICANCE: The role of SEMA7A has been studied in several cancer types, but its function in ER+ BC remains less well understood. In future studies, we will explore the mechanisms by which SEMA7A signals in the cell and to promote tumor cell survival. Delineating these mechanisms will help optimize treatment combinations to improve BC patient survival.