Abstract 2802: Establishing and optimizing treatment-naïve prostate cancer patient-derived organoids culture: Implications for personalized medicine

Background: Prostate Cancer (PCa) is a heterogeneous disease. Currently available in vitro and in vivo cancer models fail to recapitulate the spectrum of clinical and biological challenges; accurate models for translational research remain a significant unmet need. Objective: The aim of this work is to employ fresh tissue specimens from a treatment-naïve cohort of patients with prostate cancer to optimize and establish 3D patient-derived organoids as an in vitro disease model for PCa progression and drug response. In addition, acknowledging the difficulty in establishing primary PCa cell lines, our aim was to generate novel PCa patient-derived cell lines. Methods: Fresh specimens were collected from treatment-naïve patients with prostate cancer during radical prostatectomy (one unaffected and one tumor). Briefly, fresh tissue samples were digested enzymatically, and the resulting cell suspensions were plated in a 3D environment that employs Matrigel as an extracellular matrix. At first, a cocktail of 12 factors, previously recognized, was used to establish organoids. Subsequently, we have optimized the recipe to a minimal 5-factors media for both organoids and cells. Organoids and the corresponding tissue specimens were characterized using immunofluorescent analysis and immunohistochemistry. Furthermore, patient-derived organoids were employed for the assessment of drug response. In addition, PCa patient-derived cell lines were generated and their culture conditions were optimized. These cells were further characterized using immunofluorescent analysis. Results: Fresh tissues were successfully established as organoids and as 2D cells using the same culture media that contains 12 original factors. The presence of prostate luminal (Cytokeratin 8, Androgen Receptor, and Prostate Specific Antigen) and basal (Cytokeratin 5 and P63) epithelial lineages was confirmed by immunohistochemical and immunofluorescent analyses. Notably, we have identified five essential components (NAC, NOG, A83, B27, and Nicotinamide) that support the establishment of organoids culture in a less expensive, more efficient manner. Moreover, we optimized the culture and maintenance of patient-derived 2D cells by plating on collagen type I and we have reduced the medium requirement to include EGF only as an essential component. Importantly, the results showed differential drug and radiation response between patient samples. Conclusion: This study provides a repertoire of novel patient-deri