Abstract 182: Bladder cancer organoids as a functional system to model different disease stages and therapy response
Authors: Minoli Martina , Cantore Thomas , Hanhart Daniel , Kiener Mirjam , Fedrizzi Tarcisio , La Manna Federico , Karkampouna Sofia , Chouvardas Panagiotis , Genitsch Vera , Rodriguez-Calero José Antonio , Compérat Eva , Klima Irena , Gasperini Paola , Kiss Bernhard , Seiler-Blarer Roland , Demichelis Francesca , Thalmann George N. , Kruithof-de Julio Marianna 
Published: April 2023

Abstract
Introduction: Interpatient heterogeneity is one of the causes of treatment failure in bladder cancer (BLCa) patients, who would therefore profit from tailor-made therapies. Toward the direction of precision medicine, patient-derived organoids (PDOs), which retain parental tumor (PT) features, have been successfully tested in different cancer types and shown to predict patients’ responses. Therefore, our study aimed to explore the ability of BLCa PDOs to retain PT features and to determine patient drug sensitivity. We correlated PDO drug response profiles to their genomic profiles and the patient's clinical history.
Methods: PDOs were derived from the suspension culture of single cells. Whole exome sequencing was performed on genomic DNA and scRNA sequencing on 3 PT/PDO pairs. Histological evaluation of PDO and PT marker expression and morphology was performed. PDOs were treated for 48h and drug response was evaluated by viability assay.
Results: We derived PDOs from non-muscle-invasive and muscle-invasive BLCa. Genomic analysis of 15 representative PT/PDOs pairs showed high similarity in terms of copy number variations and single nucleotide variants (SNVs) with preservation of peculiar BLCa alterations. PT genomic heterogeneity was preserved in PDOs as demonstrated by the correlation between SNVs clonality profiles of PT/PDOs pairs. Moreover, marker analyses at the scRNA and protein levels supported that PDOs retained the main tumor phenotype. Interestingly, PDO grew accordingly to three morphologies linked to marker expression and PT stage.PDOs were used in drug screen assays for testing standard-of-care (SOC) and FDA-approved drugs. PDO responses were highly heterogeneous highlighting interpatient heterogeneity. In 2 case, PDO sensitivity mimicked the patient’s response to SOC and in a few cases correlated with the sample-specific genomic background. Due to the high relapse rate of BLCa, we performed 2 longitudinal studies. In the first one, PDOs from a relapse collected after epirubicin treatment showed less sensitivity to the drug compared to the baseline sample. Moreover, the SNVs' mean clonality of relapse PDOs was significantly higher than the baseline PDOs which were characterized by mutations in DNA damage repair genes (e.g., ATM, FANC1, ERCC2, and BRCA2). We hypothesize a drug-induced selection of a pre-existing epirubicin-resistant population. In the second study, PDOs from the cystectomy and the following relapse showed similar genomic and drug sensitivity profiles suggesting that the first sample could be informative for adjuvant therapy.
Conclusion: We established PDOs from different BLCa stages and grades which preserve PT features and can be implemented in drug screening assays for personalized approaches. The power of PDOs in precision medicine was highlighted by the longitudinal studies that showed that PDOs mirrored patient response and tumor evolution in vitro.
Citation Format: Martina Minoli, Thomas Cantore, Daniel Hanhart, Mirjam Kiener, Tarcisio Fedrizzi, Federico La Manna, Sofia Karkampouna, Panagiotis Chouvardas, Vera Genitsch, José Antonio Rodriguez-Calero, Eva Compérat, Irena Klima, Paola Gasperini, Bernhard Kiss, Roland Seiler-Blarer, Francesca Demichelis, George N. Thalmann, Marianna Kruithof-de Julio. Bladder cancer organoids as a functional system to model different disease stages and therapy response [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 182.