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- Cheng, Dantong, et al.
(författare)
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MicroRNA-20a-5p promotes colorectal cancer invasion and metastasis by downregulating Smad4
- 2016
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Ingår i: Oncotarget. - : IMPACT JOURNALS LLC. - 1949-2553. ; 7:29, s. 45199-45213
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tumor metastasis is one of the leading causes of poor prognosis for colorectal cancer (CRC) patients. Loss of Smad4 contributes to aggression process in many human cancers. However, the underlying precise mechanism of aberrant Smad4 expression in CRC development is still little known. Results: miR-20a-5p negatively regulated Smad4 by directly targeting its 3UTR in human colorectal cancer cells. miR-20a-5p not only promoted CRC cells aggression capacity in vitro and liver metastasis in vivo, but also promoted the epithelial-to-mesenchymal transition process by downregulating Smad4 expression. In addition, tissue microarray analysis obtained from 544 CRC patients clinical characters showed that miR-20a-5p was upregulated in human CRC tissues, especially in the tissues with metastasis. High level of miR-20a-5p predicted poor prognosis in CRC patients. Methods: Five miRNA target prediction programs were applied to identify potential miRNA(s) that target(s) Smad4 in CRC. Luciferase reporter assay and transfection technique were used to validate the correlation between miR-20a-5p and Smad4 in CRC. Wound healing, transwell and tumorigenesis assays were used to explore the function of miR-20a-5p and Smad4 in CRC progression in vitro and in vivo. The association between miR-20a-5p expression and the prognosis of CRC patients was evaluated by Kaplan-Meier analysis and multivariate cox proportional hazard analyses based on tissue microarray data. Conclusions: miR-20a-5p, as an onco-miRNA, promoted the invasion and metastasis ability by suppressing Smad4 expression in CRC cells, and high miR-20a-5p predicted poor prognosis for CRC patients, providing a novel and promising therapeutic target in human colorectal cancer.
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- Cheng, Yirui, et al.
(författare)
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Comparison of serum exosome isolation methods on co-precipitated free microRNAs.
- 2020
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Exosomes are nano-sized extracellular vesicles containing different biomolecules such as proteins and microRNAs (miRNAs) that mediate intercellular communication. Recently, numerous studies have reported the important functions of exosomal miRNAs in disease development and the potential clinical application as diagnostic biomarkers. Up to now, the most commonly used methods to extract exosomes are ultracentrifugation (UC) and precipitation-based commercial kit (e.g., ExoQuick). Generally, both UC and ExoQuick method could co-isolate contaminating proteins along with exosomes, with the UC method yielding even purer exosomes than ExoQuick. However, the comparison of these two methods on co-precipitated free miRNAs is still unknown.Methods: In this study, we isolated exosomes from the human serum with exogenously added cel-miR-39 by UC and ExoQuick and compared the proportion of cel-miR-39 co-precipitated with exosomes extracted by these two methods.Results: Using exogenous cel-miR-39 as free miRNAs in serum, we concluded that ExoQuick co-isolates a small proportion of free miRNAs while UC hardly precipitates any free miRNAs. We also found that incubation at 37 °C for 1 h could decrease the proportion of free miRNAs, and exosomal miRNAs like miR-126 and miR-152 also decreased when RNase A was used. In conclusion, our findings provide essential information about the details of serum exosome isolation methods for further research on exosomal miRNAs.
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- Mi, Yushuai, et al.
(författare)
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miR-181a-5p promotes the progression of gastric cancer via RASSF6-mediated MAPK signalling activation
- 2017
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Ingår i: Cancer Letters. - : ELSEVIER IRELAND LTD. - 0304-3835 .- 1872-7980. ; 389, s. 11-22
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Tidskriftsartikel (refereegranskat)abstract
- We previously discovered that Ras association domain family member 6 (RASSF6) was downregulated and predicted poor prognosis in GC patients. However, the mechanisms of the down regulation of RASSF6 in GC remained unclear. Increasing evidence indicates that dysregulation of microRNAs promotes the progression of cancer through the repression of tumour suppressors. Here, we identified miR-181a-5p as a novel regulator of RASSF6 in GC. Functionally, ectopic expression or silencing of miR-181a-5p, respectively, promoted or inhibited GC cell proliferation, colony formation and cell cycle transition, as well as enhanced or prevented the invasion, metastasis of GC cells and epithelial to mesenchymal transition of GC cells in vitro and in vivo. Molecularly, miR-181a-5p functioned as an onco-miRNA by activating the RASSF6-regulated MAKP pathway. Overexpression or silencing of RASSF6 could partially reverse the effects of the overexpression or repression of miR-181a-5p on GC progress caused by activation of the MAKP pathway in vitro and in vivo. Clinically, high miR-181a-5p expression predicted poor survival in GC patients, especially combined with low RASSF6 expression. Collectively, we identified miR-181a-5p as an onco-miRNA, which acts by directly repressing RASSF6 in GC. (C) 2017 The Authors. Published by Elsevier Ireland Ltd.
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| 5. |
- Zhao, Senlin, et al.
(författare)
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miR-4775 promotes colorectal cancer invasion and metastasis via the Smad7/TGF beta-mediated epithelial to mesenchymal transition
- 2017
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Ingår i: Molecular Cancer. - : BIOMED CENTRAL LTD. - 1476-4598. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Background: Despite advancements in the diagnosis and treatment of colorectal cancer (CRC), many patients die because of tumor metastasis or recurrence. Therefore, identifying new prognostic markers and elucidating the mechanisms of CRC metastasis and recurrence will help to improve the prognosis of the disease. As dysregulation of microRNAs is strongly related to cancer progression, the aim of this study was to identify the role of miR-4775 in the prognosis of CRC patients and the underling mechanisms involved in CRC progression. Methods: qPCR and in situ hybridization were used to evaluate the expression of miR-4775 in 544 pairs of paraffin-embedded normal and CRC tissues. Kaplan-Meier analysis with the log-rank test was used for survival analyses. Immunohistochemical staining was applied to investigate the expression of miR-4775-regulated Smad7/TGF beta pathway-associated markers. In vitro and in vivo invasion and metastasis assays were used to explore the function of miR-4775 in the progression of CRC. Results: miR-4775 was identified as a high-risk factor for CRC metastasis and recurrence, with high levels predicting poor survival among the 544 studied CRC patients. Furthermore, high miR-4775 expression promoted the invasion of CRC cells as well as metastasis and the epithelial to mesenchymal transition (EMT) via Smad7-mediated activation of TGF beta signaling both in vitro and in vivo. Downregulating miR-4775 or overexpressing Smad7 reversed the tumor-promoting roles of miR-4775/ Smad7/TGF beta in vitro and in vivo. Conclusion: miR-4775 promotes CRC metastasis and recurrence in a Smad7/TGF beta signaling-dependent manner, providing a new therapeutic target for inhibiting the metastasis or recurrence of the disease.
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