A Novel Enhanced Green FluorescentProtein-Expressing NOG Mouse for Analyzingthe Microenvironment of Xenograft Tissues

Abstract

The interaction between transplanted cells and host tissues is important for the growth and maintenance of transplanted cells. To analyze the mechanisms of these interactions, a systemic fluorescent protein-expressing mouse is a useful recipient. In this study, we generated a novel NOG strain, which strongly expresses enhanced green fluorescent protein (EGFP; PgkEGFP-NOG), especially in the liver, kidney, gastrointestinal tract, and testis. Because the host tissues expressed EGFP, xenotransplanted human cancer cells were clearly identified as EGFP-negative colonies in PgkEGFP-NOG mice. Immunohistochemical analysis revealed that EGFP-expressing stromal tissues formed a complicated tumor microenvironment within xenograft tissues. Moreover, a similar microenvironment was observed in human iPS cell-derived teratomas. Collectively, these results indicated that a suitable microenvironment is essential for the growth and maintenance of xenotransplanted cells and that PgkEGFP-NOG mice represent a useful animal model for analyzing the mechanisms of microenvironment formation.

The Use of a Green Fluorescent Protein Porcine Model to Evaluate Host Tissue Integration into Extracellular Matrix Derived Bionanocomposite Scaffolds

“…Areas of host connective tissue that did not contain the scaffold were also imaged and did not have any dark bundles that could be interpreted as scaffold fibers (Figure 4(b)). This type of interpretation is consistent with the work of Higuchi et al in which xenotransplanted cells in GFP mice were identified by GFP-negative areas [47].…”

Collagen XVII regulates tumor growth in pancreatic cancer through interaction with the tumor microenvironment

“…We also injected AK4.4 cells subcutaneously into immunodeficient NOG mice, which lack T cells, B cells, and NK cells and in which the function of macrophages and dendritic cells is attenuated, 26 to examine whether immune cells are required for the suppression of AK4.4 tumor growth by COL17A1. Unexpectedly, we found that the growth of AK4.4‐Col17a1 tumors was also suppressed relative to that of AK4.4‐vector tumors in NOG mice (Figure 5E−G ), suggesting that suppression of tumor growth by COL17A1 was not primarily due to increased infiltration of immune cells but rather to other unknown mechanisms.…”

An antibody-based approach for the in situ evaluation of mouse contribution in human stem cell-derived xenografts

“…The vast majority of them, including DNA 8,9 -and RNA [10][11][12][13] -based PCR and reverse transcription quantitative real-time PCR (RT-qPCR), species-specific transcriptome [14][15][16][17][18][19][20] and proteome 21,22 analyses as well as flow cytometry [23][24][25] , are molecular profiling approaches which require tissue dissociation or lysis and do not address host contribution in situ on a single cell level. To investigate the unperturbed interaction between the tumor and its microenvironment, the use of genetically modified cells or mouse models expressing fluorescent reporter proteins [26][27][28][29][30] might want to be avoided. Others, inluding less common DNA [31][32][33] -and RNA 34,35 -in situ hybridization as well as broadly used IHC [36][37][38][39][40][41] , do address this aspect but harbor the limitations to be either difficult to evaluate and interpret, as this is the case for in situ hybridization approaches, or to rely on mouse-specific probes or antibodies which target only one particular cell type (Fig.…”