title: Human cancer xenografts in outbred nude mice can be confounded by polymorphisms in a modifier of tumorigenesis.
abstract: Tumorigenicity studies often employ outbred nude mice, in the absence of direct evidence that this mixed genetic background will negatively affect experimental outcome. Here we show that outbred nude mice carry two different alleles of Pla2g2a, a genetic modifier of intestinal tumorigenesis in mice. Here, we identify previous unreported linked polymorphisms in the promoter, noncoding and coding sequences of Pla2g2a and show that outbred nude mice from different commercial providers are heterogeneous for this polymorphic Pla2g2a allele. This heterogeneity even extends to mice obtained from a single commercial provider, which display mixed Pla2g2a genotypes. Notably, we demonstrated that the polymorphic Pla2g2a allele affects orthotopic xenograft establishment of human colon cancer cells in outbred nude mice. This finding establishes a non-cell-autonomous role for Pla2g2a in suppressing intestinal tumorigenesis. Using in vitro reporter assays and pharmacological inhibitors, we show promoter polymorphisms and nonsense-mediated RNA decay (NMD) as underlying mechanisms that lead to low Pla2g2a mRNA levels in tumor-sensitive mice. Together, this study provides mechanistic insight regarding Pla2g2a polymorphisms and demonstrates a non-cell-autonomous role for Pla2g2a in suppressing tumors. Moreover, our direct demonstration that mixed genetic backgrounds of outbred nude mice can significantly affect baseline tumorigenicity cautions against future use of outbred mice for tumor xenograft studies.
authors.affiliation: Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045 Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt.
authors.forename: Maged
authors.initials: M
authors.lastname: Zeineldin
authors.affiliation: Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045.
authors.forename: Derek
authors.initials: D
authors.lastname: Jensen
authors.affiliation: Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045.
authors.forename: Smita R
authors.initials: SR
authors.lastname: Paranjape
authors.affiliation: Department of Urology, University of Kansas Medical Center, Kansas City, Kansas 66160.
authors.forename: Nikhil K
authors.initials: NK
authors.lastname: Parelkar
authors.affiliation: Department of Urology, University of Kansas Medical Center, Kansas City, Kansas 66160.
authors.forename: Iman
authors.initials: I
authors.lastname: Jokar
authors.affiliation: Department of Urology, University of Kansas Medical Center, Kansas City, Kansas 66160.
authors.forename: George A
authors.initials: GA
authors.lastname: Vielhauer
authors.affiliation: Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045 klneuf@ku.edu.
authors.forename: Kristi L
authors.identifier: http://orcid.org/0000-0003-3653-9385
authors.initials: KL
authors.lastname: Neufeld
mesh_terms: D000483:Alleles; D000818:Animals; D063646:Carcinogenesis / Q000235:genetics*; D003001:Cloning, Molecular; D005838:Genotype; D054501:Group II Phospholipases A2 / Q000235:genetics* / Q000378:metabolism; D045325:HCT116 Cells; D006801:Humans; D007422:Intestines / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D059365:Nonsense Mediated mRNA Decay; D010957:Plasmids / Q000235:genetics; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays / Q000379:methods*
chemical_list: D012333:RNA, Messenger; D054501:Group II Phospholipases A2; C516287:PLA2G2A protein, human; C516288:Pla2g2a protein, mouse
keywords: Apc-mouse models; Pla2g2a/Mom1; nonsense- mediated RNA decay; nude mice; xenograft model