| BackgroundColorectal cancer is a prevalent malignancy worldwide,with a continuously rising incidence and mortality rate over the past decade.The anti-metabolite 5-fluorouracil(5-Fu)is a classic and basic chemotherapy drug widely used in the treatment of colorectal cancer.However,tumor cells are prone to develop resistance to anti-tumor drugs,resulting in poor chemotherapy efficacy,so it is urgent to solve the problem of chemotherapy resistance.It is urgent to find the markers of 5-Fu chemotherapy resistance in colorectal cancer and explore its drug resistance mechanism.With the rise of transcriptome technology and bioinformatics technology,more and more genes’ roles and functions have been revealed.In our early research,we used full transcriptome sequencing technology to find non-coding RNA closely related to 5-fluorouracil resistance of colorectal cancer,and studied the role of key non-coding RNA in chemoresistance of colorectal cancer.We will continue to use transcriptome sequencing technology and bioinformatics analysis to screen and study the role of specific genes in the regulation of 5-fluorouracil chemotherapy resistance in colorectal cancer.Objective:To screen the core target gene that affects the occurrence of 5-Fu chemotherapy resistance in colorectal cancer,and explore the role and mechanism of this gene on colorectal cancer drug-resistant cells.MethodsWe analyzed the GSE28702 microarray from the GEO database to identify differentially expressed genes(DEGs)related to 5-fluorouracil chemoresistance and sensitivity in colorectal cancer patients.We used the Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genome(KEGG)databases to identify enriched pathways.We constructed a protein-protein interaction(PPI)network using the STRING analysis database and identified core genes using the cyto Hubba tool in Cytoscape.We generated a 5-fluorouracil resistant cell line HCT8/5-Fu and performed high-throughput transcriptome sequencing to identify expression differences of hub genes.Diagnostic value was evaluated using the receiver operating characteristic(ROC)curve,and the expression and prognosis of key genes were analyzed using the colorectal adenocarcinoma(COAD)dataset from The Cancer Genome Atlas(TCGA)database.We constructed a transferrin(TF)gene overexpression vector and transfected it into HCT8/5-Fu cells to detect tumor cell viability by MTT colorimetry.We used flow cytometry to measure cell apoptosis and cell cycle,and qRT-PCR to detect the expression and regulation of gene mRNA.ResultsA total of 239 differentially expressed genes(DEGs)were identified,including 185up-regulated and 54 down-regulated genes.These DEGs were mainly enriched in functions and pathways related to xenobiotic metabolism,cellular protein metabolism,extracellular and endocytic vesicles,and drug metabolism.Using protein-protein interaction(PPI)analysis,20 hub genes were identified,and high-throughput transcriptome sequencing revealed that the transferrin(TF)gene was significantly downregulated in drug-resistant cells(P<0.01),consistent with the DEG analysis.The diagnostic performance of TF was moderate,with an area under the ROC curve(AUC)of 0.676.Tumor tissues with low TF expression were significantly associated with colorectal cancer(P<0.01),and patients with high TF expression had longer overall survival times(P<0.05).Up-regulating TF increased the sensitivity of drug-resistant cells to 5-Fu(P<0.05),induced apoptosis,and caused G0/G1 cell cycle arrest(P<0.05).Moreover,TF overexpression inhibited the expression of ABCC1 in drug-resistant cells(P<0.01),and high TF expression was associated with lower ABCC1 expression(P<0.05).ConclusionThrough bioinformatics and transcriptome sequencing,we identified the TF gene as a target gene for 5-Fu resistance in colorectal cancer.Our results suggest that TF plays a crucial role in reducing 5-Fu resistance by regulating the expression of ABCC1.This study provides a new target for the diagnosis and treatment of 5-Fu resistance in colorectal cancer. |
