Analysis Of The Role Of CHMP7 In The Development Of Colorectal Cancer

Objective:The purpose of this study was to investigate the aberrant expression of CHMP7 in CRC tissues and its role in the development and progression of CRC.Methods:1.Expression difference analysis by bioinformatics technology: mining the TCGA database for CRC-related gene expression profile data and analyzing the differential expression levels of CHMP7 in CRC tumor tissues and normal tissues after data processing.2.Clinicopathological correlation analysis: the differential expression of CHMP7 in CRC tissues and normal tissues was analyzed by using R software on the processed TCGA data.The target data set was divided into CHMP7 high expression group and low expression group using the median CHMP7 expression as the boundary.The correlation between CHMP7 expression level and clinical characteristics of CRC patients,such as patient age,gender,tumor stage,lymph node infiltration,was analyzed.3.Prognostic analysis: the GEPIA online website was used to explore the correlation between CHMP7 expression levels in public databases and with the prognosis of patients with CRC.4.Functional enrichment analysis: genes interacting with CHMP7 were searched in GEPIA database and String database,and KEGG and GO functional enrichment analysis of CHMP7 and its related genes were performed with Metascape online website.5.Mutation analysis: 11,495 sample information of the pan-cancer dataset was downloaded from the TCGA database for CHMP7 mutation analysis,and the significantly altered regions of target gene amplification or deletion were scored by GISTIC 2.0,and the change in CHMP7 copy number level in each tumor was calculated based on the scores derived from GISTIC.6.Immune infiltration analysis: the correlation between CHMP7 expression and the number of infiltrating immune cells in CRC tumor tissue was analyzed using the GSVA package of R software(version 1.34.0),with the algorithm chosen as ss GSEA and Spearman correlation analysis between groups.7.Clinical sample validation: rt-PCR to examine the differential expression of CHMP7 between CRC tissues and normal tissues adjacent to cancer.IHC was applied to stain paraffin sections and collect relevant clinicopathological information to analyze the correlation between CHMP7 expression level and the information.8.Cell function assay: Human CRC cell lines with CHMP7 overexpression and silencing were constructed,and results were verified by rt-PCR and Western blot assays.The effect of CHMP7 expression level on the proliferation and migration ability of colorectal cancer cells was verified by CCK8,clone formation,scratch assay and Transwell assay.Results:1.CHMP7 expression levels were downregulated in CRC tissues.2.Low CHMP7 expression was associated with more advanced TNM stage,lymphatic infiltration and poorer prognosis.3.Patients in the CHMP7 low expression group had a worse prognosis.4.The major mutation type of CHMP7 in a variety of tumors is deletion of expression.5.CHMP7 and its interacting gene functions are mainly enriched in: positive regulation of DNA damage checkpoint;transcriptional regulation of oncogene TP53;maintenance of neuronal stem cell population;cascade response of MAPK pathway and activation of protein kinase activity.6.CHMP7 expression positively correlates with the level of infiltration of multiple immune cells,such as CD8 T cells,Th2 cells and cytotoxic cells.7.Clinical samples were validated with the use of rt-PCR and IHC to analyze the difference in expression levels of the target gene CHMP7 in CRC tumor tissues and paired paracancerous tissues.The patients were further divided into CHMP7 high expression group and CHMP7 low expression group according to CHMP7 IHC staining results.Analysis of the basic information collected from the patients by group revealed that CHMP7 expression levels were significantly lower in CRC tumor tissues,and patients in the low CHMP7 expression group usually had a more advanced TNM stage(p=4.2e-4),a higher proportion of lymph node infiltration(p=0.02)and a shorter overall survival(OS)(p=6.2e-3).8.The results of cell function experiments demonstrated that the upregulation of CHMP7 expression was followed by a significant decrease in cell proliferation,a reduction in the number of formed cell clones,and a weakening of cell migration ability.In contrast,further downregulation of CHMP7 expression in the HT 29 cell line promoted cell proliferation and migration,a result consistent with the previous differential expression analysis.Conclusion:1.CHMP7 expression levels were significantly down-regulated in CRC tumor tissues.2.Low CHMP7 expression was associated with more advanced tumor stage and shorter OS of patients.3.Down-regulation of CHMP7 expression promoted the proliferation and migration ability of colorectal cancer cell lines,while up-regulation of expression inhibited the proliferation and migration ability of colorectal cancer cell lines.