3357 TL1 Team Approach to Using a Combination of Ganglioside 2 and 3 as an Immunoaffinity Target for Circulating Osteosarcoma Cell Detection

Abstract

OBJECTIVES/SPECIFIC AIMS: The objective of our collaboration is to develop a strong trans-disciplinary team consisting of microfluidics engineers, cancer biologists, and clinicians, to identify a universal marker to detect circulating osteosarcoma cells (COC) using microfluidic devices. Our goals are 3 fold: 1) Identify cell surface markers unique to osteosarcoma (OS) for COC isolation, 2) Develop a Geometrically Enhanced Mixing (GEM) device to isolate COCs, and 3) Evaluate the efficacy of GEM device to detect COCs in patients with OS. The long term goal of this collaboration is to utilize this cell detection approach to evaluate treatment efficacy and correlate the presence of circulating osteosarcoma cells with metastatic incidence. METHODS/STUDY POPULATION: In this phase of our study, we have identified an abundant and conserved cell surface marker across a panel of OS cell lines. Flow cytometry was used to evaluate the relative expression of Epithelial Cell Adhesion Molecule (EpCAM), and Ganglioside 2 or/and 3 (GD2/3) on a panel of OS cell lines. An antibody coated GEM microfluidic device is used to affirm the efficacy of GD2/3 to capture COCs. Further capture studies will be conducted using OS cell spiked blood samples. Analysis of variance (ANOVA) will be used to determine any significant difference in capture efficiency between EpCAM, GD2/3 cell surface markers. RESULTS/ANTICIPATED RESULTS: Our results demonstrate that EpCAM is not a suitable marker for COC detection. Results from our flow cytometry studies demonstrate that GD2/3 expression is significantly higher than EpCAM expression, across all OS cell lines within our panel. The cell capture efficiency strongly correlates with the cell surface expression data obtained from flow cytometry analysis. DISCUSSION/SIGNIFICANCE OF IMPACT: OS is the most common primary bone tumor and the third leading cause of pediatric cancer deaths. At diagnosis, 80% of patients will present with metastasis, however only 20% of these cases are clinically detectable. Innovative strategies to identify patients at risk of metastasis would allow for stratification of intervention therapies. Liquid biopsies are a novel alternative to current diagnostic imaging systems to monitor metastatic incidence and treatment efficacy. The detection of circulating tumor cells (CTCs) through routine blood sampling has the potential to be used clinically for earlier detection, monitoring the treatment of metastatic cancers and surveying the effect of therapeutic interventions on metastasis. To date, the majority of the studies on CTCs have evaluated their presence in carcinomas. Although sarcomas are rare, they generally have a poorer prognosis. This study will address one of the unmet medical needs in the field of CTC detection; the identification of cell surface OS makers to improve binding specificity, increase purity, and maintain a high capture efficiency.