Transgenic mice that accept Luciferase‐ or GFP‐expressing syngeneic tumor cells at high efficiencies

Abstract

Jellyfish green fluorescent protein (GFP) and firefly luciferase can serve as versatile tracking markers for identification and quantification of transplanted cancer cells in vivo. However, immune reactions against these markers can hamper the formation of syngraft tumors and metastasis that follows. Here, we report two transgenic (Tg) mouse lines that express nonfunctional mutant marker proteins, namely modified firefly luciferase (Luc2) or enhanced GFP (EGFP). These mice, named as Tg-mLuc2 and Tg-mEGFP, turned out to be immunologically tolerant to the respective tracking markers and thus efficiently accepted syngeneic cancer cells expressing the active forms of the markers. We then injected intrarectally the F hybrid Tg mice (BALB/c × C57BL/6J) with Colon-26 (C26) colon cancer cells that originated from a BALB/c mouse. Even when C26 cells expressed active Luc2 or EGFP, they formed primary tumors in the Tg mice with only 10 cells per mouse compared with more than 10 cells required in the nontransgenic BALB/c hosts. Furthermore, we detected metastatic foci of C26 cells in the liver and lungs of the Tg mice by tracking the specific reporter activities. These results show the usefulness of the Tg mouse lines as recipients for transplantation experiments with the non-self tracking marker-expressing cells.

A mouse model that is immunologically tolerant to reporter and modifier proteins

“…Engraftment of BFP, AzamiGreen and mKO2 transduced OT-I T cells was also observed but was only marginally improved relative to WT mice, suggesting that these proteins have a low immunogenicity in the C57BL/6 strain used in this study. As antigen presentation is MHC restricted, the value of the Tol transgene for these FPs may be more profound in other mouse strains, as e.g., exemplified by the preferential immunogenicity of eGFP in Balb/c mice relative to C57BL/6 strains 5,16,17 .…”

Brain Metastasis Cell Lines Panel: A Public Resource of Organotropic Cell Lines

“…Although some of these aspects could be circumvented (e.g., tolerogenic GEMM; ref. 128), novel variants of nonimmunogenic reporters (27), the use of humanized mouse models or using imaging methods based on endogenous reporters (i.e., MRI to minimize the effects of reporters on immunity), a good strategy is to combine and validate experimental findings using several models.…”

Modeling High-grade serous ovarian carcinoma using a combination of in vivo electroporation and CRISPR/Cas9 mediated genome editing

“…These mice will be highly useful to study clonal evolution and mechanisms of peritoneal metastasis formation. Although immunogenicity of transgenes would be a concern from using transgene-based lineage tracing in cancer models, this would be conquered by expressing non-functional transgenes to induce immune tolerance 46 .…”