Abstract 195: Establishment and validation of pheochromocytoma organoids for high-throughput drug screening

Abstract Pheochromocytomas and paragangliomas (PPGL) are rare catecholamine-secreting neuroendocrine tumors known for their genetic diversity. They can be categorized in discrete molecular subgroups, including tumors presenting with pseudohypoxia or kinase signaling activation. Metastatic and recurrent PPGLs have few therapeutic options, in part due to the lack of appropriate study models. Here, we report progress on the establishment of viable organoids from n=10 distinct sporadic or familial PPGLs spanning varios genotypes. We also perform detailed histological, molecular, biochemical, and functional characterization. The ten PPGLs were obtained from patients with distinct clinical history and diverse ethnic and genetic backgrounds. We show how we can generate PPGL organoids from fresh and frozen tissue in a format compatible with histologic characterization and high-throughput drug screening (mini-rings, Phan et al, 2019, Al Shihabi et al, 2022). Our mini ring approach uses fewer cells with no need for expansion in vitro, and is amenable to implement automation for facile high-throughput studies. We can quantify PPGL growth in culture using a machine learning-based pipeline (Al Shihabi et al, 2022). All PPGL organoids for which sufficient number of cells could be obtained grew, regardless of the genotype and molecular subtype. PPGL organoids could be cultured short term (6 days) as well as long term (4 weeks). We investigated cellular composition by staining for the neuroendocrine marker chromogranin A, the sustentacular cell marker S100, and the vascular marker CD34. We also analyzed the expression of catecholamines in the cell culture supernatant by LC/MS/MS. We confirmed that secreted catecholamines matched the primary tumor pattern. Lastly, we present the results of pilot drug screening on both short and long term cultures. Drug sensitivity profiles pinpoint tumor-specific responses. In conclusion, we can establish PPGL organoids that largely recapitulate features of the tumor of origin. These models will provide the ability to investigate tumor initiation and progression for various genetic backgrounds and may reveal novel patterns of drug sensitivity and resistance. Citation Format: Maite Calucho, ZiMing Cheng, Huyen Thi-Lam Nguyen, Ahmad Al Shihabi, Hector Gonzalez-Cantu, Qianjin Guo, Maneesha Thaker, Nicole Bechmann, Graeme Eisenhofer, Yanli Ding, Patricia Dahia, Alice Soragni. Establishment and validation of pheochromocytoma organoids for high-throughput drug screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 195.