Abstract A092: Ovarian tumor organotypic slices cultures for functional drug screening (TOSCA)
Authors: Trozzi Rita , Nero Camilla , Buttarelli Marianna , Sillano Francesca , Ripoli Cristian , Sollazzo Raimondo , Bianchetti Giada , Lucchetti Donatella , Sgambato Alessandro , Grassi Claudio , De Spirito Marco , Scambia Giovanni 
Published: March 2024

Introduction: Ovarian cancer is still the leading cause of death among all gynaecological cancers in developed countries. High-grade serous ovarian cancer patients (HGSOC) with platinum-resistant or refractory disease have limited therapeutic options thus very poor prognosis. Early identification of these patients could limit useless undesirable effects and explore more effective therapeutic options. Short-term ex vivo assays might address such unmet needs, providing a truly personalized approach. Methods: Eleven advanced HGSOC patients have been enrolled. At the time of primary debulking surgery, tumor biopsies from different tumor anatomic sites (omentum and/or peritoneum) have been collected and divided in two sections: one section has been included in OCT and then processed for H&E staining, the other section has been cut into thin 350 µm sections by a McIlwain tissue chopper and cultured in a liquid-air interface using semi-porous tissue culture inserts. At least three representative organotypic tumor slices have been harvested at different culture time points (T0-T5) and fixed in 10% buffered formalin before embedding in paraffin. To evaluate histopathological and immunohistochemical features of HGSOC tumor, H&E staining and Wilm’s tumor protein (WT1), p16, Cytokeratin 7, p53, Ki-67, PAX-8 immunostaining have been performed on organotypic tumor slices and for comparison on corresponding uncut tumor biopsy. In addition, a label-free two-photon fluorescence microscopy approach have been applied to monitor changes in the Redox Ratio (RR), calculated as, representative of metabolic modifications inside the organotypic tumour slices. This functional analysis has been matched with multiplex spatial profiling using specific markers such as EpCAM/CD326 for the epithelial compartment, α-SMA for the stromal compartment, CD45 for the immune compartment, cleaved Caspase 3 and cytochrome C for the apoptosis, Ki-67 as proliferation index. Results: The first characterization phase has been concluded on selected patients’ samples. Histopatological and immunoistochemical analysis have shown that organotypic tumors slices retained HGSOC features between the beginning and the end of the culture. When comparing with the uncut tumor biopsy, we have assessed that organotypic tumors slices maintain tumor heterogeneity. The approach based on metabolic imaging have highlighted the presence of different areas inside the tissue, with metabolic features remaining stable at the beginning and at the end of the culture. Treatment of organotypic tumors slices with cytotoxic agents, PARP inhibitors and immunotherapy is ongoing to evaluate drug response in terms of cell viability and metabolic rate. Conclusion: The proposed preclinical model seems promising and suitable for mimicking the in vivo tumor features. Further analyses are ongoing to evaluate the feasibility of organotypic tumor slices cultures as patient avatar for functional drug screening.

Citation Format: Rita Trozzi, Camilla Nero, Marianna Buttarelli, Francesca Sillano, Cristian Ripoli, Raimondo Sollazzo, Giada Bianchetti, Donatella Lucchetti, Alessandro Sgambato, Claudio Grassi, Marco De Spirito, Giovanni Scambia. Ovarian tumor organotypic slices cultures for functional drug screening (TOSCA) [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A092.