Abstract 1660: Comparison between surgical and ultrasound-guided orthotopic implantation of hepatocellular carcinoma models in mice using ultrasound and bioluminescence imaging
Authors: Payne Chris , Amer Yasmin , Storer Ruth , Hutchinson Ganisha , Harris Lucy , Miles Amanda , Yin Yinfei 
Published: June 2022

Abstract
Introduction: Orthotopic tumour mouse models are often preferred to subcutaneous models due to their increased clinical relevance and pathophysiological features, as the tumour microenvironment can influence stromal interaction, immune response, angiogenesis, tumour growth and progression as well as response to treatment. Orthotopic implantation of liver cancer cell lines can be time consuming and inefficient due to the surgical procedures involved to establish the tumour. This study assesses the benefits of replacing traditional invasive surgical orthotopic implantation of two hepatic tumour cell lines with a minimally invasive ultrasound guided approach. Tumour growth of both implantation methods were assessed using ultrasound and bioluminescence, as well as duration of surgery and animal recovery time. In addition, the immune landscape of both implantation methods was assessed using flow cytometry.
Methods: Hep3B and Hepa 1-6 cells were transfected with luciferase for bioluminescence imaging. Hep3B-luc or Hepa 1-6-luc cells were orthotopically injected into the left liver lobe of C57BL/6 mice via either conventional surgery or ultrasound guided injection. Tumour growth was measured using both Ultrasound (Fujifilm Vevo 3100 imaging system, Visualsonics) and bioluminescence (IVIS® Spectrum in vivo imaging system, Perkin Elmer). Surgery times were recorded as the duration each animal was under anaesthesia. Recovery times were reported as the time animals were held in recovery before returning to their cage. An in house validated flow cytometry T cell panel was used to assess T cell infiltration in the Hepa1-6 syngeneic model.
Results: A comparison of tumour volume versus tumour associated bioluminescence demonstrated good correlation between both methods for each cell line. The duration of surgery and post implantation recovery times were significantly reduced for mice that underwent ultrasound-guided implantation compared to surgery, as well as fewer post-operative clinical observations. No significant difference in body weight was observed throughout the study. T cell infiltration by flow cytometry assessment enabled further evaluation of potential differences in the immune landscape of Hepa 1-6 tumours.
Conclusion: Ultrasound guided implantation of orthotopic hepatic tumours is a minimally invasive technique that leads to improved recovery times for animals, which adheres to the principles of the 3R’s. The time taken for ultrasound guided implantation compared to traditional surgical methods was also significantly reduced, enabling a higher throughput of animals on study. Tumour growth kinetics in both Hep3B and Hepa 1-6 models were comparable between the 2 methods.
Citation Format: Chris Payne, Yasmin Amer, Ruth Storer, Ganisha Hutchinson, Lucy Harris, Amanda Miles, Yinfei Yin. Comparison between surgical and ultrasound-guided orthotopic implantation of hepatocellular carcinoma models in mice using ultrasound and bioluminescence imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1660.