Urine miR-21-5p as a potential non-invasive biomarker for gastric cancer

MicroRNAs as potential biomarkers for diagnosis, therapy and prognosis of gastric cancer

Despite the widespread use of endoscopy and conventional tumor biomarkers, gastric cancer (GC) remains one of the most frequent causes of cancer-related deaths worldwide due to its late diagnosis and poor response to treatment. Valuable and practical biomarkers are urgently needed to screen patients with a high risk of GC that can complement endoscopic diagnosis. Such biomarkers will enable the efficient prediction of therapeutic response and prognosis of GC patients and favor the establishment of an effective treatment strategy for each and every patient. MicroRNAs (miRNAs) are a class of small non-coding RNA sequences that play important roles in modulating key biological processes by regulating the expression of target genes. Expectedly, miRNAs are abnormally expressed within the tumor tissue and in associated biological fluids of GC patients including their blood, gastric juice, and urine. Accumulating evidence indicates that miRNAs are potential biomarkers with multiple diagnostic functions for GC. Here, we review recent advances and challenges in using miRNAs, particularly biofluid miRNAs, as GC biomarkers with potential clinical applications including diagnosing, clinically staging, and predicting malignant behaviors, therapy response, recurrence after surgery and survival time.

Inhibition of miR-21-5p suppresses high glucose-induced proliferation and angiogenesis of human retinal microvascular endothelial cells by the regulation of AKT and ERK pathways via maspin

The aim of the present study is to investigate the role of miR-21-5p in angiogenesis of human retinal microvascular endothelial cells (HRMECs). HRMECs were incubated with 5 mM glucose, 30 mM glucose or 30 mM mannitol for 24 h, 48 h or 72 h. Then, HRMECs exposed to 30 mM glucose were transfected with miR-21-5p inhibitor. We found that high glucose increased the expression of miR-21-5p, VEGF, VEGFR2 and cell proliferation activity. Inhibition of miR-21-5p reduced high glucose-induced proliferation, migration, tube formation of HRMECs, and reversed the decreased expression of maspin as well as the abnormal activation of PI3K/AKT and ERK pathways. Down-regulation of maspin by siRNA significantly increased the activities of PI3K/AKT and ERK pathways. In conclusion, inhibition of miR-21-5p could suppress high glucose-induced proliferation and angiogenesis of HRMECs, and these effects may partly dependent on the regulation of PI3K/AKT and ERK pathways via its target protein maspin.