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BACKGROUND: Colorectal cancer (CRC) is the second leading cause of cancer-related death, with high morbidity worldwide. There is an urgent need to find reliable diagnostic biomarkers of CRC and explore the underlying molecular mechanisms. Exosomes are involved in intercellular communication and participate in multiple pathological processes, serving as an important part of the tumor microenvironment. AIM: To investigate the proteomic characteristics of CRC tumor-derived exosomes and to identify candidate exosomal protein markers for CRC. METHODS: In this study, 10 patients over 50 years old who were diagnosed with moderately differentiated adenocarcinoma were recruited. We paired CRC tissues and adjacent normal intestinal tissues (> 5 cm) to form the experimental and control groups. Purified exosomes were extracted separately from each tissue sample. Data-independent acquisition mass spectrometry was implemented in 8 matched samples of exosomes to explore the proteomic expression profiles, and differentially expressed proteins (DEPs) were screened by bioinformatics analysis. Promising exosomal proteins were verified using parallel reaction monitoring (PRM) analysis in 10 matched exosome samples. RESULTS: A total of 1393 proteins were identified in the CRC tissue group, 1304 proteins were identified in the adjacent tissue group, and 283 proteins were significantly differentially expressed between them. Enrichment analysis revealed that DEPs were involved in multiple biological processes related to cytoskeleton construction, cell movement and migration, immune response, tumor growth and telomere metabolism, as well as ECM-receptor interaction, focal adhesion and mTOR signaling pathways. Six differentially expressed exosomal proteins (NHP2, OLFM4, TOP1, SAMP, TAGL and TRIM28) were validated by PRM analysis and evaluated by receiver operating characteristic curve (ROC) analysis. The area under the ROC curve was 0.93, 0.96, 0.97, 0.78, 0.75, and 0.88 (P < 0.05) for NHP2, OLFM4, TOP1, SAMP, TAGL, and TRIM28, respectively, indicating their good ability to distinguish CRC tissues from adjacent intestinal tissues. CONCLUSION: In our study, comprehensive proteomic profiles were obtained for CRC tissue exosomes. Six exosomal proteins, NHP2, OLFM4, TOP1, SAMP, TAGL and TRIM28, may be promising diagnostic markers and effective therapeutic targets for CRC, but further experimental investigation is needed.
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BACKGROUND: The carcinogenesis of colorectal cancer (CRC) involves many different molecules and multiple pathways, and the specific mechanism has not been elucidated until now. Existing studies on the proteomic signature profiles of CRC are relatively limited. Therefore, we herein aimed to provide a more comprehensive proteomic signature profile and discover new prognostic markers and therapeutic targets by performing proteomic analysis of CRC and paired normal tissues. AIM: To investigate the proteomic signature and identify novel protein prognostic biomarkers of CRC. METHODS: Cancer tissues and paired normal tissues were collected from 48 patients who underwent surgical removal at the China-Japan Friendship Hospital from January 2020 to June 2021. Data independent acquisition (DIA) quantitative proteomic analysis was performed using high-performance liquid chromatography-mass spectrometry/mass spectrometry (nano-UHPLC-MS/MS) to identify differentially expressed proteins, among which those with a P adj value (t test, BH correction) < 0.05 and an absolute fold change (|log2FC|) > 2 were identified as potential markers. Differentially expressed proteins were selected by bioinformatics analysis and validated by immunohistochemical tissue microarrays, and their association with prognosis was further analyzed with the Gene Expression Profiling Interactive Analysis database to identify prognostic protein biomarkers of CRC. RESULTS: Significantly differential protein expression was observed between cancer tissues and normal tissues. Compared with normal tissues, 1115 proteins were upregulated and 705 proteins were downregulated in CRC based on P adj < 0.05 and |log2FC| > 2, and bioinformatics analysis revealed that the differentially expressed proteins were involved in multiple biological processes associated with tumorigenesis, including ribosome biogenesis in eukaryotes, focal adhesion, extracellular matrix-receptor interactions and other tumor metabolism processes. Moreover, cyclin-dependent kinase inhibitor 2A (CDKN2A) expression was markedly upregulated in CRC, as validated by immunohistochemistry (0.228 vs 0.364, P = 0.0044), and was significantly enriched in tumor proliferation and signal transduction pathways such as the cell cycle and p53 signaling pathways. High CDKN2A expression was significantly correlated with poor prognosis (P = 0.021). These results demonstrated that CDKN2A functions as a driver of CRC. CONCLUSION: Our study provides a comprehensive proteomic signature of CRC and highlights CDKN2A as a potential powerful prognostic marker and precision therapeutic target.
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BACKGROUND: Early detection of colorectal neoplasms, including colorectal cancers (CRCs) and advanced colorectal adenomas (AAs), is crucial to improve patient survival. Circulating microRNAs (miRNAs) in peripheral blood are emerging as noninvasive diagnostic markers for multiple cancers, but their potential for screening colorectal neoplasms remains ambiguous. AIM: To identify candidate circulating cell-free miRNAs as diagnostic biomarkers in patients with colorectal neoplasms. METHODS: The study was divided into three phases: (1) Candidate miRNAs were selected from three public miRNA datasets using differential gene expression analysis methods; (2) an independent set of serum samples from 60 CRC patients, 60 AA patients and 30 healthy controls (HCs) was included and analyzed by quantitative real-time polymerase chain reaction for miRNAs, and their diagnostic power was detected by receiver operating characteristic (ROC) analysis; and (3) the origin and function of miRNAs in cancer patients were investigated in cancer cell lines and tumor tissues. RESULTS: Based on bioinformatics analysis, miR-627-5p and miR-199a-5p were differentially expressed in both the serum and tissues of patients with colorectal neoplasms and HCs and were selected for further study. Further validation in an independent cohort revealed that both circulating miR-627-5p and miR-199a-5p were sequentially increased from HCs and AAs to CRCs. The diagnostic power of miR-672-5p yielded an area under the curve (AUC) value of 0.90, and miR-199a-5p had an AUC of 0.83 in discriminating colorectal neoplasms from HCs. A logistic integrated model combining miR-199a-5p and miR-627-5p exhibited a higher diagnostic performance than either miRNA. Additionally, the levels of serum miR-627-5p and miR-199a-5p in CRC patients were significantly lower after surgery than before surgery and the expression of both miRNAs was increased with culture time in the culture media of several CRC cell lines, suggesting that the upregulated serum expression of both miRNAs in CRC might be tumor derived. Furthermore, in vitro experiments revealed that miR-627-5p and miR-199a-5p acted as tumor suppressors in CRC cells. CONCLUSION: Serum levels of miR-199a-5p and miR-627-5p were markedly increased in patients with colorectal neoplasms and showed strong potential as minimally invasive biomarkers for the early screening of colorectal neoplasms.
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BACKGROUND: Colorectal cancer (CRC) imposes a tremendous burden on human health, with high morbidity and mortality. Circular ribonucleic acids (circRNAs), a new type of noncoding RNA, are considered to participate in cancer pathogenesis as microRNA (miRNA) sponges. However, the dysregulation and biological functions of circRNAs in CRC remain to be explored. AIM: To identify potential circRNA biomarkers of CRC and explore their functions in CRC carcinogenesis. METHODS: CircRNAs and miRNAs differentially expressed in CRC tissues were identified by analyzing expression profiles from the Gene Expression Omnibus (GEO) database. Circ_0000375 and circ_0011536 were selected as CRC biomarker candidates. Quantitative real-time polymerase chain reaction was utilized to evaluate the expression of these 2 circRNAs in CRC tissues, serums and cell lines. Receiver operating characteristic curves were generated to assess the diagnostic performances of these 2 circRNAs. Then, functional experiments, including cell counting kit-8, wound healing and Transwell invasion assays, were performed after the overexpression of circ_0000375 and circ_0011536 in CRC cell lines. Furthermore, candidate target miRNAs of circ_0000375 and circ_0011536 were predicted via bioinformatics analysis. The expression levels of these miRNAs were explored in CRC cell lines and tissues from GEO datasets. A luciferase reporter assay was developed to examine the interactions between circRNAs and miRNAs. Based on the target miRNAs and downstream genes, functional enrichment analyses were applied to reveal the critical signaling pathways involved in CRC carcinogenesis. RESULTS: Downregulated circ_0000375 and circ_0011536 expression was observed in CRC tissues in GSE126095, clinical CRC tissue and serum samples and CRC cell lines. The areas under the curve for circ_0000375 and circ_0011536 were 0.911 and 0.885 in CRC tissue and 0.976 and 0.982 in CRC serum, respectively. Moreover, the serum levels of these 2 circRNAs were higher in patients at 30 d postsurgery than in patients before surgery, suggesting that the serum expression of circ_0000375 and circ_0011536 is related to CRC tumorigenesis. Circ_0000375 and circ_0011536 overexpression inhibited the proliferation, migration and invasion of CRC cells. Furthermore, miR-1182 and miR-1246, which were overexpressed in CRC tissues in GSE41655, GSE49246 and GSE115513, were verified as target miRNAs of circ_0000375 and circ_0011536, respectively, by luciferase reporter assays. The downstream genes of miR-1182 and miR-1246 were enriched in some CRC-associated pathways, such as the Wnt signaling pathway. CONCLUSION: Circ_0000375 and circ_0011536 may function as tumor suppressors in CRC progression, serving as novel biomarkers for CRC diagnosis and as promising candidates for therapeutic exploration.
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BACKGROUND: Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have been widely used for the treatment of early gastrointestinal cancer. Endoscopic piecemeal mucosal resection (EPMR) is derived from the combination of EMR and ESD. Delayed perforation with peritonitis after colonic EPMR is a rare but severe complication, sometimes requiring surgery. There are some associated risk factors, including patient- (location, diameter, and presence of fibrosis) and procedure-related factors. Early recognition and timely treatment are crucial for its management. CASE SUMMARY: We report a case in which delayed perforation with peritonitis was treated using endoscopic closure. A 54-year-old man was diagnosed with a 30-mm-diameter laterally spreading tumor in the colonic hepatic curvature. Fifteen hours after endoscopic resection, peritonitis caused by delayed perforation occurred and gradually aggravated. Conservative treatment was ineffective and no obvious perforation was observed. After timely endoscopic closure, the patient was discharged on postoperative day 4. CONCLUSION: In occasion of localized peritonitis aggravating without macroscopic perforation, endoscopic closure is an effective treatment for delayed perforation with stable vital signs in the early stage.
