Key Pathways Studies In Which Prion Protein Affects Tumor Lung Metastasis

Prion protein(Pr P)is a glycoprotein commonly expressed on the surface of a variety of cells.A pile of clinical studies and in vitro cellular studies suggested that its abnormal expression is closely related to the occurrence and development of tumors.However,there are few studies using Pr P knockout mice to investigate the role and mechanism of Pr P in tumor metastasis.Our previous work found that in mouse model of B16 melanoma lung metastasis,Pr P knockout mice were more easily to generate lung metastases.This current project will construct an animal model of LLC1 lung metastasis,and conduct vascular permeability and therapeutic experiments based on B16 and LLC1 lung metastasis models to reveal the key pathways of Pr P affecting tumor lung metastasis.Firstly,the LLC1 lung metastasis model was constructed in mice of three genotypes: C57WT(wide type without any genetic modification),Pr P KO(Pr P knockout type),and △OR(Pr P octapeptide repeat region knockout type),so as to investigate whether Pr P total or fragment knockout would promote LLC1 lung metastasis in vivo.Secondly,in B16 melanoma metastasis model,the lung tissues from mice of 3 genotypes was respectively collected for transcriptome sequencing.The vascular-related genes were screened out in the transcriptomics data,and their expression was validated by real-time quantitative PCR.Then,VE cadherin 5(CDH5)was selected for immunofluorescence staining to explore whether there were differences in lung blood vessels of these mice.Finally,the peptide reagent OR was injected to treat B16 and LLC1 lung metastasis.The experimental results showed that in the LLC1 lung metastasis model,the survival time of mice in the Pr P KO group and the △OR group was significantly shorter than that in the C57 WT group,and the tumor number was significantly higher than that in the C57 WT group,suggesting that Pr P deletion may accelerate the formation of lung metastases.Transcriptomics data of lung tissue showed that as compared to mice in the C57 WT group,the pulmonary vascular endothelial junction in the Pr P KO and △OR group was weakened,which may facilitate tumor cells to penetrate blood vessels and generate lung metastasis.Finally,after treatment the peptide reagent OR,mice showed extended survival time and reduced tumor number compared to the control group.In summary,Pr P knockout may reduce the integrity of the endothelial connection in the pulmonary blood vessels in mice,resulting in easier extravasation of tumor cells and more metastasis.In addition,the OR region of Pr P may contribute to the formation of vascular barrier.