Investigating the Effect of Liver Regeneration on Tumor Growth: Development of a Mouse Model with Orthotopic Implantation of Patient-derived HCC Organoids

Abstract

Abstract Background Recurrence after hepatocellular carcinoma (HCC) treatment is a significant problem. It affects more than 70% of patients undergoing liver resection. Recurrence can arise from undetected micro metastasis or de novo cancer. Clinical and experimental studies suggest that liver regeneration ensuing surgical resection may activate occult micro-metastasis leading to regeneration induced tumor recurrence. However, in vivo patient-derived organoid (PDO) HCC models that are translatable to patient tumors are sparse. Aims Here, we aim to establish a new in vivo model to understand the impact of liver regeneration on HCC tumor growth. Methods PDOs were generated from HCC tissue obtained from patients undergoing liver resection at the Clarunis University Digestive Health and Care Center and transduced with firefly luciferase. Implantation was performed via laparotomy and orthotopic injection of the organoids in the right superior liver lobe. Tumor growth is monitored by in vivo bioluminescence imaging until the endpoint of the experiment. As a primary endpoint tumor growth two weeks after liver resection was defined. Experimental groups underwent either minor (30%) or major (65%) hepatectomy of tumor-free liver, whereas the control group received a re-laparotomy with subsequent closure of the abdomen. Normal liver and tumor tissue were characterized using immunohistochemistry. Results Two HCC-PDO lines were successfully implanted. Compared to the control, after minor and major liver resection the mean weight increased significantly to 0.82% (p < 0.0001) respectively 0.99% (p < 0.0001). Preliminary data about the tumor volume have yet to be concluded. Histology and immunohistochemistry staining for HCC confirmed the origin of the PDOs from the original patient tumor. Conclusion The establishment of an orthotopic xenograft mouse model for HCC PDO was successful. Through liver resection, a regenerative environment could be achieved, to investigate the molecular behavior of HCC recurrence after surgery. This offers the basis to study potential new targets and mechanisms to improve HCC-treatment.