Establishment and characterization of pancreatic cancer organoids resistant to FOLFIRINOX anticancer drugs

다국어 초록 (Multilingual Abstract)

While treatment of pancreatic ductal adenocarcinoma (PDAC), a devastating disease, has advanced over the past two decades, the prognosis remains very poor, with a 5-year survival rate of only 8%. FOLFIRINOX, a combination of 5-fluorouracil, irinotecan (SN-38), and oxaliplatin, has shown excellent early tumor response rates, allowing surgical resection in many patients who were initially inoperable. However, the significantly lower early tumor response and long-term survival rates are a result of rapid acquisition of chemotherapy resistance, which remains a major therapeutic challenge. Reports on resistance models for FOLFIRINOX combination therapy are limited, as few have been established in vitro or in vivo. Meanwhile, patient-derived tumor organoids (PDO) bridge the gap between 2D adherent culture and in vivo xenograft models, establishing themselves as an important model system in epithelial cancer research. In this study, we established a PDO model resistant to FOLFIRINOX therapy and compared it with non-resistant PDO to elucidate the mechanisms of resistance and contribute to the development of future treatment strategies. First, we used a naïve pancreatic ductal adenocarcinoma (PDAC) organoid model to estimate the physiological concentrations of each of the three drugs. Next, naïve PDAC organoids were treated with FOLFIRINOX for 72 hours, followed by a 96-hour drug-free period, repeating the treatment cycle 12 times. We systematically compared treated organoids with the control naïve organoids to assess gene expression, proliferation, growth, and viability associated with cancer stemness and tumor aggressiveness. In this study, we generated resistant organoids through repeated drug exposure, and these resistant organoids demonstrated significantly reduced sensitivity to FOLFIRINOX treatment compared to naïve organoids. Furthermore, this resistant model mimics the gradual progression of chemotherapy resistance, from cell proliferation inhibition to growth arrest and relapse, similar to the pattern observed in clinical patients, suggesting it as a valuable research tool for studying resistance mechanisms and developing effective treatments. This study presents an in vitro model demonstrating resistance to three drugs included in a combination regimen. This novel patient-derived tumor organoid (PDO) model will be a valuable tool for elucidating the mechanisms of acquired chemotherapy resistance, providing essential knowledge for the development of novel therapeutic strategies for pancreatic cancer. Keywords: Pancreas, Cancer, PDAC (Pancreatic adenocarcinoma), Organoid, FOLFIRINOX, Chemoresistance, Chemotherapeutic Response

목차 (Table of Contents)

• Abstract ⅰ
• Contents ⅱ
• List of Figures ⅳ
• List of Tables ⅴ
• Introduction 1
• Materials and Methods 3
• 1. Patient Information 3
• 2. Establishment of Organoids 3
• 3. Histopathological Evaluation 3
• 4. Quantification Assay 4
• 5. Organoid Drug treatment with FOLFIRINOX and IC50 measurement 4
• 6. qPCR Analysis 4
• 7. RNA-Seq Analysis 4
• 8. Statistical Analysis 5
• Results 6
• 1. Establishment and Morphological Characterization of 0- and 12-Cycle Patient-Derived Pancreatic Cancer Organoids 6
• 2. Drug Response of pancreatic cancer organoids to FOLFIRINOX components 9
• 3. Longitudinal morphological changes in naïve pancreatic cancer organoids during repeated FOLFIRINOX treatment 16
• 4. Assessment of FOLFIRINOX resistance in pancreatic cancer organoids 18
• 5. Changes in gene expression during the induction of FOLFIRINOX resistance 25
• 6. Transcriptomic profiling of pancreatic cancer organoids with acquired FOLFIRINOX resistance 28
• Discussion 33
• References 36
• 국문 요약 38