384. ROBUST CULTURE OF PATIENT-DERIVED ESOPHAGEAL ADENOCARCINOMA ORGANOIDS OF SINGLE CELL LINEAGE.

Background Esophageal adenocarcinoma (EAC) has a high mutational rate leading to significant intratumoral heterogeneity. We have previously generated patient-specific organoid models of EAC from endoscopic biopsies and resection specimens. It is unclear whether intratumoral heterogeneity is retained in these organoid models, but we did observe morphologic heterogeneity in these organoid cultures. In this study, we sought to generate methods to isolate clonal organoids from patient-derived EAC organoid cultures. Methods Patient derived EAC organoids were resuspended into single cell solution and dead cells were stained with DAPI. Automatic cell sorter was used to pipette a single live cell into Matrigel coated 96 well plate. Single cell per well was pipetted and checked within 24 hours using light microscope. Cells were coated with a second coat of Matrigel and media and allowed to grow into full size organoids. Organoids of single morphology were expanded and collected for further analysis. Results We have established a high-throughput method to culture patient-derived organoids deriving from a single cell, allowing for lineage analysis. Organoids grown from a single cell take up to 21 days to grow to a full-sized organoid of distinct morphology. We identified 4 distinct EAC organoid morphologies which we have designated: solid, cystic, budding, and grape. Conclusion Isolating EAC organoid morphology is the first step in studying inter- and intra- tumour heterogeneity in EAC organoids. This method allows for studying morphology-transcriptome and morphology-drug response correlations. [ABSTRACT FROM AUTHOR]