[Animal modeling] - Establishment of endothelial conditional knockout EMCN mouse model and comparative analysis of lung metastasis of tumor

  Objective To establish a mouse model of endothelial cell conditional knockout EMCN gene, and investigate the difference of lung metastasis between C57BL/6 mice and endothelial cell conditional knockout EMCN mice.

  Methods The endothelial cell specific Tek CreERT2 mice were hybridized with EMCFlox/flox mice, and the offspring of male EMCFlox/wt/Tek CreERT2+were mated with female EMCFlox/flox mice to obtain endothelial cell specific knockout EMCN gene mice (EMCFlox/flox/Tek CreERT2+, EMCEcho). The accuracy and efficiency of gene knockout were verified at the level of DNA and protein. After genomic DNA of mice was extracted, Tek CreERT2 and FLOX sites were detected by PCR amplification. After induction by Tamoxifen, the expression of EMCN protein in tissues was detected by Western Blot. Phenotypes of normal C57BL/6 mice and EMCEcko mice were observed and organs were stained with HE. In order to confirm the effect of EMCN knockout on tumor metastasis, C57BL/6 of LLC cells was injected into the tail vein of EMCEcho mice. Two weeks later, the lungs were dissected to detect lung metastasis, and the lung metastasis results of the two groups of mice were statistically compared. The LLC cells were subcutaneously injected into C57BL/6 and EMCEcko mice, and the subcutaneous tumor was resected 2 weeks later. The lung metastasis was observed 2 and 3 weeks after the operation, and the lung tissues of the two groups were stained with HE. The lung metastasis results of the two groups of mice were statistically compared and analyzed.

  Results EMCFlox/flox/Tek creERT2+mice were successfully constructed from DNA and protein levels. HE section analysis of mouse tissues showed that there was no abnormality in organ development of gene knockout mice. Both C57BL/6 and EMCEcho mice with tumor resection after tail vein injection of LLC and subcutaneous injection of LLC can develop lung metastasis. Compared with C57BL/6 mice, the absence of EMCN in endothelial cells significantly promotes lung metastasis in mice.

  Conclusion Endothelial EMCN conditional knockout mice were successfully obtained. The ability of tumor lung metastasis in endothelial EMCN knockout mice was significantly better than that in normal C57BL/6 mice. It is expected to provide an animal model for rapid lung metastasis in various studies of tumor lung metastasis animal models.