Abstract 196: A platform for rapid patient-derived cutaneous neurofibroma organoid establishment and screening
Authors: Nguyen Huyen T. , Kohl Emily , Bade Jessica , Eng Stefan E. , Tosevska Anela , Shihabi Ahmad Al , Hong Jenny J. , Dry Sarah , Boutros Paul C. , Panossian Andre , Gosline Sara , Soragni Alice 
Published: April 2023

Abstract
Localized cutaneous neurofibromas (cNFs) are benign tumors that arise in the dermis of patients affected by Neurofibromatosis Type 1 syndrome, a common disorder driven by alterations in the NF1 gene. cNF tumors are heterogenous and comprised of different cell types such as Schwann cells, fibroblasts, and mast cells. While cNFs do not undergo malignant transformation, they carry significant co-morbidities, including itching, pain, and socio-emotional repercussions. There is currently no therapy for cNF beside surgical removal or desiccation, which are typically unable to eliminate all lesions due to their number, with patients developing as many as several hundred cNFs, as well as additional concerns of scarring and potential re-growth. A lack of models to investigate cNFs growth and perform drug screenings has hindered drug discovery and development studies thus far. We set out to develop high throughput screening-compatible patient-derived cNF organoids to perform translational studies. Tumor organoids are promising ex vivo models to recapitulate a patient’s tumor histology, molecular features, and drug responses. To support drug discovery efforts focused on identifying effective systemic therapies for cNF, we have developed an approach to routinely establish and screen cNF tumor organoids. Here we present of our systematic characterization of media conditions together with molecular and functional analysis to validate cNF organoids as a model system. We enrolled n=12 Neurofibromatosis Type 1 syndrome patients in this study and procured cNF tumors that we dissociated to single cells to establish organoids in nine different media compositions. We performed a detailed comparison to the tumor of origin using a combination of immunohistochemistry, flow cytometry, DNA methylation and RNAseq for a subset of samples (n=6 tumors from 5 patients). cNF organoids were successfully established and grown in all cases, regardless of the NF1 alteration present. We determined the optimal medium that had the highest combined correlation (parental vs organoid) across all assays as well as promoted the highest rate of growth ex vivo. We also demonstrated feasibility of screening cNF organoids using our established mini-ring pipeline (Phan et al, 2019; Nguyen and Soragni, 2020; Al Shihabi et al, 2022). In summary, we have optimized conditions for ex vivo growth of cNF organoids that closely recapitulate the molecular and cellular heterogeneity of these tumors as measured by immunohistopathology, DNA methylation, RNAseq and flow cytometry. Our tractable patient-derived cNF organoid platform enables the rapid screening of hundreds of FDA-approved drugs in a patient- and tumor-specific manner.
Citation Format: Huyen T. Nguyen, Emily Kohl, Jessica Bade, Stefan E. Eng, Anela Tosevska, Ahmad Al Shihabi, Jenny J. Hong, Sarah Dry, Paul C. Boutros, Andre Panossian, Sara Gosline, Alice Soragni. A platform for rapid patient-derived cutaneous neurofibroma organoid establishment and 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 196.