This proposal responds to the provocative question PQ9: What methods can be developed to effectively study small or rare populations relevant to cancer research? We will address this question by generating organoid models of pheochromocytomas and paragangliomas (PPGL) to fill gaps in the mechanisms underlying tumor behavior and in therapeutic opportunities. PPGLs are rare catecholamine-secreting, neural crest-derived tumors originating from adrenal or extra adrenal paraganglia, respectively. Malignant PPGLs can only be recognized after detection of metastases, implying a late diagnosis. Approximately 30-40% of paragangliomas, and 10-15% of pheochromocytomas can develop metastases. In addition, PPGLs are clinically heterogeneous, can be recurrent and invasive, even without metastasis, but predictors of clinical behavior are lacking. Treatment options are currently limited, with modest effects on survival, and advances in this area are dampened by a scarcity of research models. Therefore, there is a critical need for developing models to uncover biological mechanisms that facilitate clinical outcome prediction and reveal molecular vulnerabilities which can be explored for therapeutic purposes. Our preliminary data indicate that we can successfully generate PPGL organoids that are amenable for drug screen. Our aims are: 1) to determine if PPGL organoids recapitulate features of the parental tumor; 2) to leverage PPGL organoids to investigate outstanding biological questions, including the existence of cell subtypes that may be related to tumor outcome, and 3) to utilize PPGL organoids for high- throughput drug screening that uncover vulnerabilities for future therapeutic testing, including novel leads suggested in our preliminary data. The proposed project will serve as a useful resource for designing future studies to decode the cellular and molecular mechanisms underlying PPGL development and clinical heterogeneity. Results from these studies may provide the groundwork for future testing of candidate drugs that might have immediate clinical application.

To address “PQ9: What methods can be developed to effectively study small or rare populations relevant to cancer research” we will develop organoids of rare neuroendocrine tumors pheochromocytomas and paragangliomas (PPGL). Currently there are no markers of clinical behavior and malignant PPGLs can only be recognized after metastases develop, for which there are few treatment options. PPGL organoids will enable investigation of tumor markers of outcome and drug screen to identify potential new therapies.