Development and translational imaging of a TP53 porcine tumorigenesis model
Jessica C. Sieren, … , Dawn E. Quelle, Christopher S. Rogers
Jessica C. Sieren, … , Dawn E. Quelle, Christopher S. Rogers
Published August 8, 2014
Citation Information: J Clin Invest. 2014;124(9):4052-4066. https://doi.org/10.1172/JCI75447.
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Technical Advance Oncology

Development and translational imaging of a TP53 porcine tumorigenesis model

Abstract

Cancer is the second deadliest disease in the United States, necessitating improvements in tumor diagnosis and treatment. Current model systems of cancer are informative, but translating promising imaging approaches and therapies to clinical practice has been challenging. In particular, the lack of a large-animal model that accurately mimics human cancer has been a major barrier to the development of effective diagnostic tools along with surgical and therapeutic interventions. Here, we developed a genetically modified porcine model of cancer in which animals express a mutation in TP53 (which encodes p53) that is orthologous to one commonly found in humans (R175H in people, R167H in pigs). TP53R167H/R167H mutant pigs primarily developed lymphomas and osteogenic tumors, recapitulating the tumor types observed in mice and humans expressing orthologous TP53 mutant alleles. CT and MRI imaging data effectively detected developing tumors, which were validated by histopathological evaluation after necropsy. Molecular genetic analyses confirmed that these animals expressed the R167H mutant p53, and evaluation of tumors revealed characteristic chromosomal instability. Together, these results demonstrated that TP53R167H/R167H pigs represent a large-animal tumor model that replicates the human condition. Our data further suggest that this model will be uniquely suited for developing clinically relevant, noninvasive imaging approaches to facilitate earlier detection, diagnosis, and treatment of human cancers.

Authors

Jessica C. Sieren, David K. Meyerholz, Xiao-Jun Wang, Bryan T. Davis, John D. Newell Jr., Emily Hammond, Judy A. Rohret, Frank A. Rohret, Jason T. Struzynski, J. Adam Goeken, Paul W. Naumann, Mariah R. Leidinger, Agshin Taghiyev, Richard Van Rheeden, Jussara Hagen, Benjamin W. Darbro, Dawn E. Quelle, Christopher S. Rogers

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Figure 2

Defective molecular and biological activity of the porcine p53-R167H mutant protein.

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Defective molecular and biological activity of the porcine p53-R167H mut...
(A) Known differential response of cells expressing wild-type p53 (+/+) and mutated p53-R167H alleles (+/m or m/m) to DNA damage. Figure adapted with permission from Nature (26). (B) Western blots of p53, p21, and GAPDH (loading control) levels in p53 wild-type or R167 mutant pig fibroblasts. Cells were treated with DMSO vehicle (–) or 400 ng/ml doxorubicin (Dxn) for 3 days. Lanes were run on the same gel but were noncontiguous (black line). (C) Representative histograms of cell cycle distributions for doxorubicin-treated cells from B. Red, percent of cells arrested in G1 phase (2N DNA content); blue, cells undergoing apoptosis (<2N DNA content). (D) Mutant RAS induces cellular senescence in TP53+/+ (+/+) cells, whereas TP53R167H/+ (+/m) and TP53R167H/R167H (m/m) cells escape mutant RAS-induced senescence and proliferate, during which time they sustain chromosomal alterations that foster cell transformation. (E and F) Pig fibroblasts were infected with pBabe-puro vector or pBabe-H-RASG12V-puro viruses and selected with puromycin for 7–10 days. Shown are (E) phase-contrast microscopy and (F) counts of SA-βgal–stained cells. Cells expressing mutant p53 evaded senescence and proliferated, whereas those with wild-type p53 adopted the enlarged, flattened morphology of senescent cells and stained positively for SA-βgal. Data in F are mean ± SD of 3 independent experiments. Scale bars: 100 μm. *P < 0.05, **P < 0.001 vs. vector, 2-way ANOVA.