K. V. JOSHI1,7, N. Sirpu7, M. Shanmugam7, R. R. Poonooru3,4, P. Subramanyam3,4, C. Garrett3,4, S. Schlink7, S. Gerb7, J. Porter7,10, M. Yariswamy1,7, S. Nagaraj1,7, D. Kim13, J. Kunin10, T. Hoffman8, B. Telugu3,4, J. Bryan3,5,7, J. Kaifi1,2,8,9,11,12, S. Rachagani5,6,7 1University Of Missouri, Department Of Surgery, Columbia, MO, USA 2University Of Missouri, Institute For Data Science And Informatics, Columbia, MO, USA 3National Swine Resource and Research Center, Columbia, MO, USA 4University Of Missouri, Division Of Animal Sciences, Columbia, MO, USA 5University Of Missouri, Department Of Veterinary Medicine And Surgery, Columbia, MO, USA 6Ellis Fischel Cancer Center, Department Of Medicine-Division Of Hematology And Oncology, Columbia, MO, USA 7Roy Blunt NextGen Precision Health Institute, Columbia, MO, USA 8Harry S. Truman Memorial Veterans’ Hospital, Columbia, MO, USA 9Siteman Cancer Center, St. Louis, MO, USA 10University Of Missouri, Department Of Radiology, Columbia, MO, USA 11Washington University, Division Of Public Health Sciences, St. Louis, MO, USA 12Institute of Clinical and Translational Sciences, St. Louis, MO, USA 13University Of Missouri, Department Of Veterinary Pathobiology, Columbia, MO, USA
Introduction: Lung cancer is the leading cause of cancer-associated death in the United States. Since preclinical findings in small animal models vastly do not translate into human clinics, there is an urgent need to develop relevant preclinical large animal models for lung cancer. In the present study, we describe a novel method to induce lung cancer in transgenic Oncopigs carrying Cre inducible KrasG12D and TrP53R167H mutations (Oncopigs).
Methods: The Oncopigs carrying LSL-KrasG12D / TrP53R167H transgene (n=9; 6 females, and 3 males) at 9 weeks of age were anesthetized and Adenovirus (1×1011 PFU) carrying Cre recombinase gene (Ad-Cre) plus polybrene (1:100) and IL-8 (5 ng/ml) was injected via flexible bronchoscopy with two techniques: (1) Bronchial lavage (n=6) and (2) Transbronchial needle injection (n=3) into right cranial lung lobe and once in left caudal lobe. As controls, a combination of polybrene and/or IL-8 were injected without AdCre into the contralateral lobes in the same pigs (n=5). Oncopigs were monitored via clinical monitoring, blood counts, basic metabolic panel, and contrast-enhanced computed tomography (CT) imaging at 2-, 4-, 7-, and 10 weeks post-intervention.
Results: All animals tolerated the injections well and continued to do well clinically with expected weight gains. Blood counts and metabolic panels remained normal. At the site of injection/lavage, lung masses were detected on CT imaging performed at 2 weeks post-injections. There was a decrease in masses observed on CT at 7 weeks post-intervention; however, the decrease in size of the masses coincided with increasing attenuation. One pig had a right-sided pleural effusion which was monitored and appeared unchanged 7 weeks post-intervention. No distant metastases were observed on CT imaging. Lavage-based lesions appeared to be more heterogeneous with surrounding inflammatory changes. Transbronchial-injection-based lesions appeared more consolidated and coin-shaped without surrounding inflammatory changes. Control injection sites did not show any mass growth on CT imaging.
Conclusion: Lung tumors can be induced in transgenic Oncopigs and appear to be rapidly growing following both lavage and transbronchial AdCre injection, although differences in CT imaging characteristics were observed. The autopsies on five Oncopigs revealed macroscopically varying sizes of tumors after 8 weeks post-intervention. Currently, tumors are being characterized histopathologically, while another Oncopig cohort (n=4) is monitored longitudinally for tumor growth and development of metastases.