Abstract
BackgroundColorectal cancer (CRC) is one of the most common cancers of the gastrointestinal tract and ranks third in cancer-related deaths worldwide. This study was conducted to identify novel biomarkers related to the pathogenesis of CRC based upon a bioinformatics analysis, and further verify the biomarkers in clinical tumor samples and CRC cell lines.MethodsA series of bioinformatics analyses were performed using datasets from NCBI-GEO and constructed a protein–protein interaction (PPI) network. This analysis enabled the identification of Hub genes, for which the mRNA expression and overall survival of CRC patients data distribution was explored in The Cancer Genome Atlas (TCGA) colon cancer and rectal cancer (COADREAD) database. Furthermore, the differential expression of HCAR3 and INLS5 was validated in clinical tumor samples by Real-time quantitative PCR analysis, western blotting analysis, and immunohistochemistry analysis. Finally, CRC cells over-expressing INSL5 were constructed and used for CCK8, cell cycle, and cell apoptosis validation assays in vitro.ResultsA total of 286 differentially expressed genes (DEGs) were screened, including 64 genes with increased expression and 143 genes with decreased expression in 2 CRC database, from which 10 key genes were identified: CXCL1, HCAR3, CXCL6, CXCL8, CXCL2, CXCL5, PPY, SST, INSL5, and NPY1R. Among these genes, HCAR3 and INSL5 had not previously been explored and were further verified in vitro.ConclusionsHCAR3 expression was higher in CRC tissues and associated with better overall survival of CRC patients. INSL5 expression in normal tissue was higher than that in tumor tissue and its high expression was associated with a better prognosis for CRC. The overexpression of INSL5 significantly inhibited the proliferation and promoted the shearing of PARP of CRC cells. This integrated bioinformatics study presented 10 key hub genes associated with CRC. HCAR3 and INSL5 were expressed in tumor tissue and these were associated with poor survival and warrant further studies as potential therapeutic targets.
Highlights
Colorectal cancer (CRC) incidence and mortality have been consistently increasing year-over-year
Microarray data characteristics and the identification of differentially expressed genes (DEGs) in CRCThe CRC expression microarray datasets GSE9348 and GSE110224 were calibrated and standardized, and the results are shown in Fig. 1a, d
Further analysis found that the two independent datasets contained 207 common DEGs, including 64 genes that had increased expression and 143 with decreased expression in both the CRC datasets (Fig. 1g)
Summary
Colorectal cancer (CRC) incidence and mortality have been consistently increasing year-over-year. The 2020 GLOBOCAN statistics show that the incidence of CRC makes it the third most common form of cancer worldwide and it has the second highest mortality rate [1]. Because of advancements in understanding colorectal carcinogenesis, the array of treatment options for local and advanced CRC have increased and individual treatment plans have been developed [3]. Colorectal cancer (CRC) is one of the most common cancers of the gastrointestinal tract and ranks third in cancer-related deaths worldwide. This study was conducted to identify novel biomarkers related to the pathogenesis of CRC based upon a bioinformatics analysis, and further verify the biomarkers in clinical tumor samples and CRC cell lines
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