Abstract 3990: Use of 3D tumoroid systems to define immune and cytotoxic therapeutic responses based on tumoroid and tissue slice culture molecular signatures
Authors: Niklas K. Finnberg, Prashanth Gokare, Avital Lev, Alexander W. MacFarlane, Kerry S. Campbell, Karen Kaputa, Jeffrey Farma, Luigi Grasso, Nicholas C. Nicolaides, Wafik El-Deiry
Journal: Cancer Research (2017)

Abstract Historically, the successful establishment of exponentially growing viable in vitro tumor cell cultures has been found to occur from a minority of tumor tissues following artificial selection of a sub-population of tumor cells. Such limitations make it difficult to model patient variability in drug responses in vitro. Moreover, the lack of stromal cells that play a critical role in tumor viability, growth and drug response in vivo make the prediction of tumor response of immune-based therapeutics challenging. Through recent advances in three-dimensional (3D) culture (“tumoroid”) methodologies some of these hurdles are beginning to be addressed. However, it is currently unclear to what extent such models can be engineered to retain important phenotypic properties of infiltrating immune cells from the tumor tissue of origin. To better understand these limitations, we have developed 3D tumoroids and tumor slice in vitro cultures from tumors derived from patients with colorectal cancer (CRC) to evaluate immune cell populations infiltrating cultured CRC tissues. Furthermore, we have developed a system whereby the patient’s immune cells are re-incorporated into tumoroid in vitro cultures to evaluate the ability of the culture to mimic an immunosuppressive tumor microenvironment (ITM). Here we demonstrate the development of a propagating 3D epithelial tumoroid culture system from resected CRC tissue where we assessed the response to standard FDA approved therapy within weeks of surgical resection. Interestingly, tumoroid cultures from a CRC patient were highly sensitive to the thymidylate synthase inhibitor fluorouracil (adrucil) but less sensitive to the combination of the nucleoside analog trifluridine and the thymidine phosphorylase inhibitor tipiracil (Lonsurf). We isolated approximately four (4) million immune cells using Percoll density gradient centrifugation and flow cytometry. Re-introduction of isolated immune cells derived from surrounding and infiltrating tumor tissue and CD45+ tumor infiltrating hematopoietic cells displayed prolonged (&amp;gt;10 days) survival in co-culture. Moreover, established tumor slice cultures contained both an outer epithelial and inner stromal cell compartment mimicking tumor structure in vivo. Collectively, these data suggest that CRC tumoroid in vitro assays can be used for the assessment of some therapeutic responses. While further work is required to optimize this system, 3D tumoroid and slice culture assays may represent a novel in vitro approach to assess therapeutic efficacy of novel therapeutics and evaluate mechanisms of therapy resistance in general as well as for patient-specific response. Citation Format: Niklas K. Finnberg, Prashanth Gokare, Avital Lev, Alexander W. MacFarlane, Kerry S. Campbell, Karen Kaputa, Jeffrey Farma, Luigi Grasso, Nicholas C. Nicolaides, Wafik El-Deiry. Use of 3D tumoroid systems to define immune and cytotoxic therapeutic responses based on tumoroid and tissue slice culture molecular signatures [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3990. doi:10.1158/1538-7445.AM2017-3990