Abstract 2153: The Miniature Oncopig® cancer model as an innovative large animal platform for preclinical pharmaceutical evaluation.

Abstract Background: Advances in cancer care rely on human-like preclinical animal models to evaluate safety, metabolism, pharmacokinetics, and efficacy of novel therapeutics in a translational manner. We previously developed the transgenic Oncopig®, a genotypically, anatomically, metabolically, and physiologically relevant large animal model that develops inducible tumors on demand. While the Oncopig® platform is ideal for short-term device-based therapeutic and diagnostic studies, its rapid growth and large size limits use for pharmaceutical and long-term efficacy studies. To overcome this limitation, we used the Wisconsin Miniature SwineTM (WMSTM) to develop a miniature version of the Oncopig® (WMSTM-Oncopig®). The WMSTM-Oncopig® is a valuable model for preclinical drug studies due to its reduced size in addition to predisposition to obesity, metabolic disorders, and other clinically relevant cancer comorbidities. Methods: The WMSTM-Oncopig® transgene cassette was designed to harbor Cre recombinase-inducible KRASG12D and TP53R167H driver mutations. The cassette also includes a mScarlet fluorescence gene flanked by LoxP sites, serving as a negative marker of Cre-induced recombination and driver mutation expression. Using CRISPR/Cas9 technology, the transgene cassette was inserted into the Rosa26 locus of WMSTM fibroblasts. After validation, the modified fibroblasts were used for reproductive cloning of WMSTM-Oncopigs® by somatic cell nuclear transfer. Tumor induction studies were conducted on WMSTM -Oncopig® clones (n=2) with established Oncopig® liver tumor induction protocols, while the remaining clones were used for breeding. Results: WMSTM-Oncopig® fibroblasts were selected based on fluorescent imaging (mScarlet) and sequencing. Transgene cassette functionality was confirmed based on KRASG12D and TP53R167H expression, increased proliferation, and loss of red fluorescence following nucleofection with a Cre recombinase-expressing plasmid. WMSTM-Oncopigs® formed liver tumors within 2 weeks of induction using established Oncopig® tumor induction protocols. Finally, cells isolated from 3 of 5 fetuses generated by breeding WMSTM-Oncopig® clones to wild-type WMS™ displayed red fluorescence, with genomic PCR confirming germline transmission of the transgene cassette. Conclusions: The WMSTM-Oncopig® model enables on-demand tumor induction in a clinically relevant pig breed with reduced size and growth compared to the current Oncopig® model. This, combined with predisposition to obesity and other clinically relevant cancer comorbidities supports the translational relevance of the WMSTM-Oncopig® for preclinical oncologic drug metabolism, pharmacokinetic, safety, and efficacy studies. The WMSTM-Oncopig® thus fulfills the current unmet need for translationally relevant models for preclinical investigation of novel cancer therapeutics. Citation Format: Taeyoung Shin, Jennifer J. Meudt, C Dustin Rubinstein, Brent Lehman, Lobna Elkhadragy, Matthew M. Niemeyer, Jamie Reichert, Kathryn M. Nelson, Jennifer Frank, Ashley Nelson, Paige Munns, Devon Klipsic, Eric Schmuck, Mahmoud Khalafalla, Navin Viswakarma, Jessicca Rege, Ali Pirasteh, Lawrence B. Schook, Tanja Dominko, Dhanansayan Shanmuganayagam, Kyle M. Schachtschneider. The Miniature Oncopig® cancer model as an innovative large animal platform for preclinical pharmaceutical evaluation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2153.