Methylation detection of circulating tumor cell miR-486-5p/miR-34c-5p in the progression of colorectal cancer.

AIMS: This study set out to examine the expression and methylation levels of miR-486-5p/miR-34c-5p and its mechanism of action based on the microRNA methylation level of circulating tumor cells (CTCs) in colorectal cancer (CRC) through clinical data and tissue detection. METHODS: EGFR and EpCAM immunophospholipid magnetic spheres (EpCAM-IML/EGFR-IML) were synthesized by the thin film method to capture CTCs in peripheral blood. The expression of miR-486-5p/miR-34c-5p was detected via real-time fluorescent quantitative PCR (RT-PCR). Methylation-specific PCR was implemented to detect the methylation level of miR-486-5p/miR-34c-5p, and 5-Aza-dC was used for demethylation treatment to detect the effect of changes in methylation levels on the tumor cells development. Cell Counting Kit-8 (CCK-8) analysis, transwell assay, and flow cytometry were used to determine the effects of demethylation and overexpression on the proliferation, invasion, migration, and apoptosis of CRC cells. RESULTS: The results showed that the expression and methylation levels of the miR-486-5p/miR-34c-5p isolated from CTCs were low and the methylation level was high in tumor cells and tissues. In CRC cell lines, demethylation and overexpression of miR-486-5p/miR-34c-5p could effectively inhibit the proliferation, invasion and migration of tumor cells, and facilitate tumor apoptosis (p < 0.05). CONCLUSION: The constructed CTCs sorting system has characteristics of high specificity and high sensitivity, is a supplement to tissue samples, and has guiding significance for the clinical rational use of drugs and personalized therapy.

Circulating tumor cells in the clinical cancer diagnosis.

Circulating tumor cells (CTCs) are cells that have shed into the vasculature or lymphatics from a primary tumor and are carried around the body in the blood circulation. CTCs undergo a series of migration, adhesion and aggregation to form metastases, leading to post-operative recurrence and metastasis in patients with malignant tumors. The detection and analysis of CTCs, as a new non-invasive diagnostic tool, plays an important role in tumor diagnosis, therapeutic efficacy, monitoring recurrence, prognosis assessment and tumor precision medical treatment.

Mesenchymal circulating tumor cells (CTCs) and OCT4 mRNA expression in CTCs for prognosis prediction in patients with non-small-cell lung cancer.

PURPOSE: Circulating tumor cells (CTCs) with epithelial-to-mesenchymal transition (EMT) phenotypes might be related to tumor progression while OCT4 expression is involved in tumor metastasis and poor prognosis. But the possible clinical significance of EMT phenotypes of CTCs from non-small-cell lung cancer (NSCLC) patients has still to be demonstrated. Furthermore, none has been investigated the expression of OCT4 in CTCs. We therefore identified the EMT phenotype-based subsets of CTCs and determined the OCT4 expression status of CTCs in NSCLC patients, to explore their possible clinical relevance. METHODS: 37 NSCLC patients and ten healthy volunteers were enrolled, respectively. The Canpatrol™ CTC enrichment technique was used to isolate and identify the EMT phenotype-based subsets of CTCs. OCT4 expression in each CTC was also determined. Results were correlated with patients' clinico-pathological features. RESULTS: CTCs were detected in 33 of 37 (89.2%) NSCLC patients, and no CTCs were identified in ten healthy volunteers. Three CTCs phenotypes, including epithelial, biophenotypic, and mesenchymal CTCs were identified based on the expression of EMT markers. Mesenchymal CTCs were more commonly found in patients with distant metastasis. Patients with distant metastasis tended to have a higher median CTCs number. OCT4-positive was observed in 21 of 28 (75.0%) patients. High expression of OCT4 tended to occur in advanced patients as well as in distant metastatic patients. CONCLUSIONS: The findings suggest that identification of CTCs by EMT markers as well as evaluation of OCT4 expression status by assessment of OCT4 expression in CTCs could serve as potential adjuncts for evaluating metastasis and prognosis in NSCLC patients.