Differences in chemotherapeutic drug sensitivity before and after patient-derived tumor organoid construction

Background: Patient-derived organoids (PDOs) have emerged as promising preclinical models for various tumor types. This study aimed to optimize the process of constructing 3D organoid models and facilitate the development of personalized therapies for gastric and colon cancers. Methods: Tumor tissues were divided into two parts: one part was dissociated into a single-cell suspension, and the other part was used to culture tumor organoids. RNA sequencing (RNA-seq) was performed on both tumor cells and cultured organoids. Four chemotherapeutic agents-Oxaliplatin (L-OHP), Gemcitabine (GEM), 5-Fluorouracil (5-FU), and Paclitaxel (PTX)-were utilized to assess cytotoxicity and proliferation in both organoids and freshly isolated tumor cells, then the effects of these agents were evaluated. Results: Organoids were successfully established from both surgically resected and biopsy-derived tumor tissues. Phenotypic analysis indicated that the organoids retained the histological features and expression profiles of the original tumors. Notably, the morphological characteristics of the organoids remained stable across passages, demonstrating robust growth over time. Differentially expressed genes were identified in both gastric and colon cancer PDOs. GO and KEGG pathway analyses revealed similar gene enrichment in gastric and colon PDOs. Both gastric and colon cancer PDOs exhibited increased significant sensitivity to PTX and 5-FU compared to freshly isolated cancer cells. Furthermore, the expression of most stemness-related genes was reduced after organoid culture. Conclusions: We successfully established organoid models that demonstrated robust growth and heightened drug sensitivity compared to freshly isolated tumor cells. These findings suggest that caution should be exercised when interpreting drug sensitivity results from organoid-based assays.