Background: Exosomal circular RNAs (circRNAs) in peripheral blood are considered as emerging diagnostic biomarkers of cancers. Owing to the lack of sensitive and specific biomarkers, a large number of colorectal cancer (CRC) patients were diagnosed in advanced stages leading to high mortality. This study aimed to identify circulating exosomal circRNAs as novel diagnostic biomarkers of CRC. Materials and Methods: Candidate circRNA was selected by integrating analysis of Gene Expression Omnibus (GEO) database with online program GEO2R. A total of 170 patients and 45 healthy controls were enrolled to assess the diagnostic value of circRNAs for CRC. Exosomes isolated from the serum of participants and cell cultured media were confirmed by transmission electron microscope (TEM), Nanoparticle Tracking Analysis and western blot. The expression and the diagnostic utility of circRNA were tested by qRT-PCR and receiver operating characteristic (ROC) analysis, respectively. Results: The circulating exosomal hsa-circ-0004771 with most abundant among the top ten differentially expressed circRNAs (fold change ≥1.5) was selected for further study based on the results of GEO dataset analysis. The up-regulated exosomal hsa-circ-0004771 was verified in serum of CRC patients compared to healthy controls (HCs) and patients with benign intestinal diseases (BIDs) by qRT-PCR. The area under the ROC curves (AUCs) of circulating exosomal hsa-circ-0004771 were 0.59 (95%CI, 0.457-0.725), 0.86 (95%CI, 0.785-0.933) and 0.88 (95%CI, 0.815-0.940) to differentiate BIDs, stage I/II CRC patients and CRC patients from HCs, respectively. The AUC was 0.816 (95%CI, 0.728-0.9) to differentiate stage I/II CRC patients from patients with BIDs. In addition, the elevated expression of exosomal hsa-circ-0004771 in the serum of CRC patients was tumor-derived. It was found that the expression of exosomal hsa-circ-0004771 was down-regulated expression of in the serum of postoperative CRC patients as well as cultured media of CRC cells treated with GW4869. Conclusions: Circulating exosomal hsa-circ-0004771 was significantly up-regulated in CRC patients and served as a novel potential diagnostic biomarker of CRC.
Formononetin is one of the main active components of red clover plants, and considered as a phytoestrogen. Its pharmacological effects in vivo may be either estrogenic or anti-estrogenic, mainly depending upon the estrogen levels. Our recent studies suggested that formononetin inactivated IGF1/IGF1R-PI3K/Akt pathways and decreased cyclin D1 mRNA and protein expression in human breast cancer cells in vitro and in vivo. In the present study, we further investigated the molecular mechanisms involved in the induced apoptosis effect of formononetin on breast cancer cells. Our results suggested that formononetin inhibited the proliferation of ER-positive MCF-7 cells and T47D cells. In contrast, formononetin could not inhibit the cell of growth of ER-negative breast cancer cells such as MDA-MB-435 S cells. We further found that formononetin activated MAPK signaling pathway in a dose-dependent manner, which resulted in the increased ratio of Bax/Bcl-2, and induced apoptosis on MCF-7 cells. However, when MCF-7 cells were pretreated with p38MAPK inhibitor SB203580 before formononetin, apoptosis induced by formononetin was significantly attenuated. Thus, we conclude that the induced apoptosis effect of formononetin on human breast cancer cells were related to Ras-p38MAPK pathway. Considering that red clover plants are widely used clinically, our results provide the foundation for future development of formononetin for treatment of ER-positive breast cancer.
Background: Trastuzumab resistance accounts for chemotherapy failure in gastric cancer patients in clinical practice.The significance of long non-coding RNAs (lncRNAs) in the maintenance of drug resistance in gastric cancer has been already underlined.Method: This study aimed to identify the specific role of lncRNA-ATB in gastric cancer progression and trastuzumab resistance.The downstream miRs of lncRNA-ATB and target genes of miRs were predicted by bioinformatics analysis and verified using dual luciferase reporter assay.Loss-and gain-function assays were performed to explore the roles of lncRNA-ATB, miR-200c, and zinc-finger protein 217 (ZNF217) in the cell functions and trastuzumab resistance of a trastuzumab-resistant gastric cancer cell line (NCI-N87-TR).Result: LncRNA-ATB was upregulated, while miR-200c was downregulated.Depletion of lncRNA-ATB or miR-200c elevation led to a decrease in malignant properties of NCI-N87-TR cells.LncRNA-ATB could negatively target miR-200c, which in turn inversely targeted and reduced the expression of ZNF217.Silencing of ZNF217 could inhibit cell viability and migration.Conclusion: lncRNA-ATB promoted the progression and trastuzumab resistance of gastric cancer by repressing miR-200c via ZNF217 upregulation.
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