A porcine model of osteosarcoma

Abstract

We previously produced pigs with a latent oncogenic TP53 mutation. Humans with TP53 germline mutations are predisposed to a wide spectrum of early-onset cancers, predominantly breast, brain, adrenal gland cancer, soft tissue sarcomas and osteosarcomas. Loss of p53 function has been observed in >50% of human cancers. Here we demonstrate that porcine mesenchymal stem cells (MSCs) convert to a transformed phenotype after activation of latent oncogenic TP53R167H and KRASG12D, and overexpression of MYC promotes tumorigenesis. The process mimics key molecular aspects of human sarcomagenesis. Transformed porcine MSCs exhibit genomic instability, with complex karyotypes, and develop into sarcomas on transplantation into immune-deficient mice. In pigs, heterozygous knockout of TP53 was sufficient for spontaneous osteosarcoma development in older animals, whereas homozygous TP53 knockout resulted in multiple large osteosarcomas in 7–8-month-old animals. This is the first report that engineered mutation of an endogenous tumour-suppressor gene leads to invasive cancer in pigs. Unlike in Trp53 mutant mice, osteosarcoma developed in the long bones and skull, closely recapitulating the human disease. These animals thus promise a model for juvenile osteosarcoma, a relatively uncommon but devastating disease.

Molecular genetics of osteosarcoma

“…However, it is conceivable that the “three drivers” model we propose in this review more closely mimics the development of aggressive OS since the majority of the GEMMs generated so far have a much longer latency. Furthermore, a recent study demonstrated that three sequential mutations in p53, Kras, and Myc can convert wild-type porcine mesenchymal stem cells (MSCs) into sarcoma cancer cells, mimicking key molecular aspects of human sarcomagenesis [12]. Our proposed model correlating the number of drivers and tumor latency is also in line with a mathematic model generated by epidemiology studies of a large colon cancer cohort, which found that only three driver gene mutations are required for the development of lung and colorectal cancers [76].…”

“…Overall, our understanding of the molecular basis of OS development has dramatically improved by using a cross-species approach, especially through GEMMs. Other publications on modeling OS using mouse, rat, dog, pig, and zebrafish exist, but will not be described in detail in this review [12, 26, 27, 85-88]. …”

“…Specifically, TSGs including p53, Rb, RECQL4, BLM, and WRN play a critical role in the development of OS in patients with Li-Fraumeni, hereditary retinoblastoma, Rothmund-Thomson, Bloom or Werner syndromes, respectively (Table 1). A causal role for p53 and/or Rb has been revealed across species [10, 12-15]. Genetically engineered mouse models (GEMMs) equipped with p53 and/or Rb mutations have been used to identify new driver genes, to model human osteosarcomagenesis, and to study different OS subtypes as well as metastatic and non-metastatic features [16-24].…”

Microenvironment Signals and Mechanisms in the Regulation of Osteosarcoma

“…These transformed porcine MSCs, with genomic instability and complex karyotypes, had the ability to develop into sarcomas upon transplantation into immunodeicient mice [15]. Other models also indicated that intrabone or periosteal inoculation of p53−/− or p53−/−RB−/− BM-MSCs or ASCs originated metastatic osteoblastic osteosarcoma (OS).…”

A Novel Methodology For Isolation and Primary Culture of Swine Gastric Epithelial Cells.

“…The latter group has been used in lymphoma and osteogenic tumor development under the induction of tumorigenesis in primary hematopoietic and broblastic cells, respectively. [9,13,14] Furthermore, swine primary cell lines have been established from different anatomic tissues such as mammary glands [11], kidney [12], intestine [15], trachea [12], lung [16], and alveoli [20]. These primary cells were used to evaluate gene expression patterns, drug susceptibility and cell physiology [22].…”