Inducible gene modification in the gastric epithelium of Tff1‐CreERT2, Tff2‐rtTA, Tff3‐luc mice

Abstract

Temporal and spatial regulation of genes mediated by tissue-specific promoters and conditional gene expression systems provide a powerful tool to study gene function in health, disease, and during development. Although transgenic mice expressing the Cre recombinase in the gastric epithelium have been reported, there is a lack of models that allow inducible and reversible gene modification in the stomach. Here, we exploited the gastrointestinal epithelium-specific expression pattern of the three trefoil factor (Tff) genes and bacterial artificial chromosome transgenesis to generate a novel mouse strain that expresses the CreERT2 recombinase and the reverse tetracycline transactivator (rtTA). The Tg(Tff1-CreERT2;Tff2-rtTA;Tff3-Luc) strain confers tamoxifen-inducible irreversible somatic recombination and allows simultaneous doxycycline-dependent reversible gene activation in the gastric epithelium of developing and adult mice. This strain also confers luciferase activity to the intestinal epithelium to enable in vivo bioluminescence imaging. Using fluorescent reporters as conditional alleles, we show Tff1-CreERT2 and Tff2-rtTA transgene activity in a partially overlapping subset of long-term regenerating gastric stem/progenitor cells. Therefore, the Tg(Tff1-CreERT2;Tff2-rtTA;Tff3-Luc) strain can confer intermittent transgene expression to gastric epithelial cells that have undergone previous gene modification, and may be suitable to genetically model therapeutic intervention during development, tumorigenesis, and other genetically tractable diseases. Birth Defects Research (Part A) 106:626-635, 2016. © 2016 Wiley Periodicals, Inc.

Trefoil Factor 1 Suppresses Stemness And Enhances Chemosensitivity Of Pancreatic Cancer

“…We have investigated their functions in the pancreas and liver, revealing that TFFs are responsible for regeneration and carcinogenesis in these organs 11,12,[15][16][17][18] . Interestingly, TFFs are expressed in the stem or progenitor cell niche and responsible for the regeneration of peripheral tissue 19,20 , suggesting the association of TFFs and cellular stemness. The relationship between tissue stem cells and carcinogenesis has long been debated, and it seems that loss of control of proliferation and differentiation in the stem cell niche eventually causes the development of neoplastic diseases 21,22 .…”

The kinase activity of the cancer stem cell marker DCLK1 drives gastric cancer progression by reprogramming the stromal tumor landscape

“…Co-housed, age- and gender-matched littermates were utilized for all experiments. The inducible BAC(Tff1CreERT2);Kras G12D model of murine GC has been reported previously ( 35, 59 ) and was used to generate the BAC(Tff1CreERT2);Kras G12D ; Pi3kca H1047R ; p53 R172H mouse model of invasive gastric adenocarcinoma (MFE, MB, ME, unpublished).…”

Tumor Growth Remains Refractory to Myc Ablation in Host Macrophages

“…Where indicated, LysM Cre/+ ; Myc fl/fl and LysM +/+ ; Myc fl/fl mice were additionally crossed with Gp130 F/F mice [ 18 ] to generate LysM Cre/+ ; Myc fl/fl ; Gp130 F/F and LysM +/+ ; Myc fl/fl ; Gp130 F/F animals. The Tff1 CreERT2 strain [ 19 ] was crossed with Myc fl/fl ; Gp130 F/F animals to generate Tff1 CreERT2 ; Myc fl/fl ; Gp130 F/F compound mutant mice. All animal studies were approved and conducted in accordance with the Animal Ethics Committee at La Trobe University and the Olivia Newton-John Cancer Research Institute/Austin Hospital.…”