Reconstructing The Barrett'S-Dysplasia-Adenocarcinoma Sequence From Patient-Matched Stem Cells

Abstract Introduction: Both esophageal and gastric adenocarcinoma (EAC; GAC) evolve from intestinal metaplasia (Barrett's and gastric IM, respectively) in a multi-decade and multi-step process involving transitions through low- and high-grade dysplasia often referred to as the “Correa Sequence”. In early stage EAC, each of these lesions can be seen co-existing in the 2-D topology of the distal esophagus. We have adapted methods we originally developed for cloning normal stem cells of the gastrointestinal tract to capturing stem cells of each of these lesions. We anticipate that a clonal analysis of these stem cells will reveal key steps in the evolution of highly lethal EAC. Methods: Libraries of stem cell clones were generated from a series of patient-specific endoscopic biopsies derived from normal, Barrett's, dysplasia, and EAC. Single cell-derived clones were analyzed by in vitro differentiation, whole genome expression analysis, and SNP-based copy number variation. Results: Highly undifferentiated, ground state stem cells were cloned from multiple endoscopic biopsies of patients with early EAC. Based on sampling site and adjacent biopsy histology, tissue corresponding to normal esophagus, gastric epithelia, Barrett's, and EAC were taken in these biopsies dissociated for stem cell cloning. All the clones derived showed unlimited proliferative potential and the ability to differentiate to normal or diseased epithelia in vitro. Thus the normal esophageal and gastric stem cells gave rise to squamous and gastric epithelia, the Barrett's stem cells yielded intestinal metaplasia, and dysplastic and EAC clones yielded highly proliferative and disordered epithelia marked by a loss of cell polarity. In contrast to the germline genotypes of the normal stem cells, those from Barrett's, dysplasia, and EAC sustained increasingly large numbers of copy number variation events, single nucleotide variations, and chromosomal aneuploidies. Significantly, all single cell-derived clones of EAC yielded “intestinal” adenocarcinoma following xenografting to immunodeficient mice. We are presently exploiting the genomic alterations present in hundreds of sample clones from each patient to reconstruct the evolutionary events that accompanied the progression to a highly lethal cancer. Conclusions: Stem cells from all stages of lesions along to the path to epithelial cancers can be cloned and independently propagated to yield insights into the evolution of cancer. In addition, these cloned cells should enable insights into intratumor heterogeneity, therapy resistance, and drug discovery. Citation Format: Wa Xian, Yanting Zhang, Marcin Duleba, Shan Wang, Frank McKeon. Reconstructing the Barrett's-dysplasia-adenocarcinoma sequence from patient-matched stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 215.