Surveillance after endoscopic and surgical resection of colorectal cancer

Extracellular Vesicle Membrane Protein Profiling and Targeted Mass Spectrometry Unveil CD59 and Tetraspanin 9 as Novel Plasma Biomarkers for Detection of Colorectal Cancer

Extracellular vesicles (EVs) are valuable sources for the discovery of useful cancer biomarkers. This study explores the potential usefulness of tumor cell-derived EV membrane proteins as plasma biomarkers for early detection of colorectal cancer (CRC). EVs were isolated from the culture supernatants of four CRC cell lines by ultracentrifugation, and their protein profiles were analyzed by LC-MS/MS. Bioinformatics analysis of identified proteins revealed 518 EV membrane proteins in common among at least three CRC cell lines. We next used accurate inclusion mass screening (AIMS) in parallel with iTRAQ-based quantitative proteomic analysis to highlight candidate proteins and validated their presence in pooled plasma-generated EVs from 30 healthy controls and 30 CRC patients. From these, we chose 14 potential EV-derived targets for further quantification by targeted MS assay in a separate individual cohort comprising of 73 CRC and 80 healthy subjects. Quantitative analyses revealed significant increases in ADAM10, CD59 and TSPAN9 levels (2.19- to 5.26-fold, p < 0.0001) in plasma EVs from CRC patients, with AUC values of 0.83, 0.95 and 0.87, respectively. Higher EV CD59 levels were significantly correlated with distant metastasis (p = 0.0475), and higher EV TSPAN9 levels were significantly associated with lymph node metastasis (p = 0.0011), distant metastasis at diagnosis (p = 0.0104) and higher TNM stage (p = 0.0065). A two-marker panel consisting of CD59 and TSPAN9 outperformed the conventional marker CEA in discriminating CRC and stage I/II CRC patients from healthy controls, with AUC values of 0.98 and 0.99, respectively. Our results identify EV membrane proteins in common among CRC cell lines and altered plasma EV protein profiles in CRC patients and suggest plasma EV CD59 and TSPAN9 as a novel biomarker panel for detecting early-stage CRC.

A 3-circular RNA signature as a noninvasive biomarker for diagnosis of colorectal cancer

Background

Circular RNAs (circRNAs), a novel type of noncoding RNAs, play critical roles in the initiation and progression of cancer. Emerging studies also shows that circRNAs may function as potential markers for cancer diagnosis and treatment. However, the diagnostic value of circRNAs in colorectal cancer (CRC) remains need to be unearthed.

Methods

CircRNA microarray was performed to detect the differentially expressed circRNAs in eight plasma samples, including four colorectal cancer (CRC) and four normal samples. Besides, the results of microarray were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, ROC curve evaluation was performed to calculate the diagnostic value of significantly dysregulated circRNAs. In order to predict the potential mechanism of the significant circRNAs, circRNA-miRNA-mRNA network was constructed based on the TargetScan, miRTarBase and MIRDB database, as well as CircInteractome online software. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to further predict the function of meaningful circRNAs.

Results

Totally three differentially expressed circRNAs were identified in CRC plasma compared to normal plasma by circRNA microarray analysis, and the results was validated by qRT-PCR. Hsa_circ_0082182, hsa_circ_0000370 and hsa_circ_0035445 were identified and ROC curves analysis was used to calculate the single and joint diagnostic value. Furthermore, GO and KEGG analyses revealed that functions were mainly cancer-related, which indicated that the circRNAs were meaningfully associated with CRC cell proliferation and metastasis.

Conclusion

In conclusion, we have identified three circRNAs that are dysregulated in CRC plasma, including hsa_circ_0082182, hsa_circ_0000370 and hsa_circ_0035445. ROC curves showed that these circRNAs might have diagnostic value for colorectal cancer. Furthermore, bioinformatics analysis indicated that the above-mentioned circRNAs might be involved in the development of CRC.

Regulatory effects of lncRNA ATB targeting miR-200c on proliferation and apoptosis of colorectal cancer cells

This investigation was intended to elucidate whether long noncoding RNA (lncRNA)-activated by transforming growth factor-β (ATB) interacting with miR-200c could mediate colorectal cancer (CRC) progression, offering potential strategies for diagnosing and treating CRC. Here totally 315 patients with CRC were recruited, and their CRC tissues and adjacent normal tissues were gathered. Concurrently, four colon cancer cell lines (ie, SW620, Lovo, HCT116, and SW480) and the human colon mucosal epithelial cell line (NCM460) were also purchased. Moreover, si-ATB, si-NC, miR-200c mimic, miR-200c inhibitor, and miR-NC were prepared for transfection into the CRC cells, and their effects on CRC cell lines were evaluated based on the conduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, and flow cytometry assay. Eventually, the Luciferase reporter gene assay was carried out to judge if there existed a targeted relationship between ATB and miR-200c. The results of Cox regression analyses suggested that overexpressed lncRNA ATB, underexpressed miR-200c, poor tumor differentiation, lymph-vascular invasion, and perineural invasion were symbolic of shortened survival of the patients with CRC (all P < .05). Besides, transfection of pcDNA3.1-ATB and miR-200c inhibitor could boost the viability and proliferation of Lovo and SW620 cell lines (all P < .05). Meanwhile, the expressions of p53 and p21 were also reduced under treatments of pcDNA3.1-ATB and miR-200c inhibitor (P < .05). In addition, CDK2 seemed to reverse the contribution of miR-200c to intensifying viability and proliferation of Lovo and SW420 cell lines (P < .05). Furthermore, ATB might downregulate miR-200c expression by targeting it (P < .05), and CDK2 was subjected to dual regulation of both ATB and miR-200c (P < .05). In conclusion, the lncRNA ATB/miR-200c/CDK2 signaling was responsible for intensified proliferation and prohibited apoptosis of CRC cells, which might provide effective approaches for diagnosing and treating CRC.

Factors related to colorectal cancer in advanced adenomas and serrated polyps: a further step toward individualized surveillance

AIM

The risk of presenting synchronous or metachronous neoplasm, either adenoma or carcinoma, increases after an initial colonic lesion develops. It is known as tumor multicentricity and constitutes the rationale for surveillance programs. This study was designed to identify the clinical, pathologic, and molecular features related to previous or synchronous colorectal cancer (CRC) in patients with advanced adenomas (AA) or serrated polyps (SP).

PATIENTS AND METHODS

We carried out a prospective analysis of 4143 colonoscopies performed at our medical department between 1 September 2014 and 30 September 2015. Patients with AA/SP associated with previous or synchronous CRC are compared with patients with solitary AA/SP. We also performed immunohistochemical for the mismatch repair proteins in 120 AA or SP, 60 of them related to CRC.

RESULTS

Three-hundred and seventy-nine AA or SP were removed. Among these, 66 (17.3%) were associated with a previous (n=31) or synchronous CRC (n=35). Age older than or equal to 65 years (odds ratio: 1.15, 95% confidence interval: 1.05-1.26, P=0.002) and male sex (odds ratio: 2.13, 95% confidence interval: 1.3-3.49, P=0.003) were found to be independent predictive factors for CRC in patients with AA/SP by multivariate analysis. Only one of the 120 AA/SP available for immunohistochemical testing showed loss of staining and it was not related to CRC.

CONCLUSION

In patients with AA or SP, it is possible to identify a subgroup that is more likely to be associated with CRC and then prone to tumor multicentricity. These results have potential implications for establishing criteria for a more targeted surveillance.

Incidence and predictors of adenoma after surgery for colorectal cancer

OBJECTIVE

Patients with colorectal cancer (CRC) are at increased risk for developing metachronous premalignant and malignant lesions. However, its real incidence and underlying risk factors are still unclear, and therefore quality measures for colonoscopy under this indication have not been completely established. The aim of this study was to assess the incidence of and risk factors for the development of adenomas after surgery for CRC.

PATIENTS AND METHODS

A total of 535 patients submitted to curative surgery for CRC between January 2008 and December 2011 were selected and their clinical records and surveillance colonoscopies were reviewed.

RESULTS

During a median follow-up of 62 months, 39.4% of the patients developed adenomas, 17.6% advanced adenomas and 3.4% developed metachronous cancers. Male sex [adjusted odds ratio (AOR)=1.99; 95% confidence interval (CI): 1.29-3.07] was an independent risk factor for adenomas during follow-up and absence of a high-quality baseline colonoscopy was the only independent risk factor for advanced adenomas (AOR=1.78; 95% CI: 1.03-3.07) and metachronous cancer (AOR=7.05; 95% CI: 1.52-32.66). In patients who had undergone a high-quality colonoscopy at baseline and at the first follow-up, the presence of adenomas (odds ratio=12.30; 95% CI: 2.30-66.25) and advanced adenomas (odds ratio=10.50; 95% CI: 2.20-50.18) in the first follow-up colonoscopy was a risk factor for the development of metachronous advanced adenomas during the subsequent surveillance.

CONCLUSION

Undergoing a high-quality baseline colonoscopy is the most important factor for reducing the incidence of advanced lesions after CRC surgery. All patients remain at high-risk for adenomas and advanced adenomas, but standardized follow-up should be adjusted after the first year of follow-up.