Abstract 5025: From OR to bench: Identification of variables affecting success in generating patient derived organotypic spheroids (pDOTS)

Background: The complex interaction between tumor cells and the immune system has led to increased efforts focused on development of ex vivo systems that recapitulate the tumor microenvironment and model responses to immune checkpoint blockade. Recently, we demonstrated successful ex vivo growth of organotypic tumor spheroids and profiling of PD-1 blockade in syngeneic models and patient tumors 1 . Optimization of tissue processing from the operating room to the lab for patient-derived materials can further aid these efforts. Here, we identify pre-analytical variables that may impact tumor characterization in ex vivo systems. Methods: We conducted an evaluation of pre-analytical variables for tumor tissue in a cohort of mesothelioma and non-small cell lung cancer (NSCLC) cases. Pre-analytical variables included neoadjuvant chemotherapy administration, pleurodesis status, type of surgery, presence of fibrosis, and onset of warm and cold ischemia during tissue retrieval and processing. Prior to surgery, medical records were reviewed for pathology, chemotherapy, and pleurodesis status. On surgery day, time of tissue removal or clamping of the pulmonary artery was recorded as onset of warm ischemia. Tissue was transported to pathology and allocations to research were made. Specimens were placed in culture media and ice; placement on ice was recorded as onset of cold ischemia. Arrival of tissue in lab was recorded. Chart and observational data were correlated with tissue analysis at the bench followed by 4-color immunofluorescence to characterize tumor and immune components of spheroids. Results: A cohort of mesothelioma and NSCLC samples were followed from the operating room to the research lab. The average time between onset of warm and cold ischemia was 60 minutes (range 33-100 min). Mean time for removal of tissue in the OR to arrival in lab was 104 minutes (range 87-137 min). Two patients received neoadjuvant chemotherapy and were among 2 of 3 cases where fibrotic samples were collected. Fibrosis was often associated with more extensive surgery via extrapleural pneumonectomy and lower tumor content per microscopy and immunofluorescence. Conclusions: Prolonged ischemic times were associated with poor tissue viability. In two cases, pre-therapeutic status was linked to tissue fibrosis, extensive surgery, low tumor yield, and failed spheroid generation. More data can help elucidate variable significance. These initial findings highlight the unique challenges associated with performing studies on live tumor tissue, and suggest that further streamlining of processes for tissue collection in the OR can optimize success of ex vivo cancer models in guiding functional precision therapies. Citation Format: Dalia Larios, Amir Aref, Elena Ivanova, Brandon Piel, Andrew Portell, David A. Barbie, Raphael Bueno, Cloud Paweletz. From OR to bench: Identification of variables affecting success in generating patient derived organotypic spheroids (pDOTS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5025.