No abstract

MicroRNAs are a family of small non-coding RNAs that constitute a prevalent gene regulation. In this study, we showed the expression of miR-512-5p is downregulated in non-small cell lung cancer (NSCLC) patient tumor samples compared to its paired normal lung tissues. Moreover, expression of miR-512-5p was increased by retinoic acid treatment. Overexpression of miR-512-5p induced apoptosis of NSCLC cell lines A549 and H1299, and miR-512-5p inhibitor reversed this effect in H1299 cells stably expressing miR-512. miR-512-5p inhibited glycolysis and migration in NSCLC cells, but shows no effect on cell proliferation. We identified p21 as a target gene of miR-512-5p. Overexpression of miR-512-5p led to the decrease of p21 protein and mRNA level. Knockdown of p21 resulted in similar effects on apoptosis and glycolysis as that observed of miR-512-5p overexpression, as well as rescued the effect of miR-512-5p inhibitor on cell apoptosis in H1299 cells stably expressing miR-512. In conclusion, our present study revealed miR-512-5p was able to target p21 to induce apoptosis and inhibit glycolysis in A549 and H1299 cell lines.

No abstract

Background/Aims: Epigallocatechin gallate (EGCG) has established protective actions against myocardial ischemia/reperfusion (I/R) injury by regulating autophagy. However, little is known about the mechanisms of EGCG in posttranscriptional regulation in the process of cardioprotection. Here we studied whether microRNAs play a role in EGCG-induced cardioprotection. Methods: The myocardial I/R injury in vitro and in vivo model were made, with or without EGCG pretreatment. The upregulation and silencing of microRNA-384-5p (miR-384) and Beclin-1 in H9c2 cell lines were established. Rats were transfected with miR-384 specific shRNA. Dual-luciferase reporter gene assay was conducted to verify the relationship between miR-384 and Beclin-1. TTC staining was performed to analyze the area of myocardial infarct size. Cell viability was monitored by cell counting kit-8 (CCK-8). The release of cardiac troponin-I (cTnI) was examined by ELISA. The levels of autophagy-related genes or proteins expression were evaluated by qRT-PCR or Western blotting. Autophagosomes of myocardial cells were detected by transmission electron microscopy and laser scanning confocal microscope. Results: I/R increased both autophagosomes and autolysosomes, thereby increasing autophagic flux both in vitro and in vivo. Pretreatment with EGCG attenuated I/R-induced autophagic flux expression, accompanied by an increase in cell viability and a decrease in the size of myocardial infarction. MiR-384 expression was down-regulated in H9c2 cell lines when subjected to I/R, while this suppression could be reversed by EGCG pretreatment. The dual-luciferase assay verified that Beclin-1 was a target of miR-384. Both overexpression of miR-384 and knocking down of Beclin-1 significantly inhibited I/R-induced autophagy, accompanied by the activation of PI3K/Akt pathway, thus enhanced the protective effect of EGCG. However, these functions were abrogated by the PI3K inhibitor, LY294002. Conclusion: We confirmed that EGCG has a protective role in microRNA-384-mediated autophagy by targeting Beclin-1 via activating the PI3K/Akt signaling pathway. Our results unveiled a novel role of EGCG in myocardial protection, involving posttranscriptional regulation with miRNA-384.

Long non-coding RNA forkhead box D3 antisense RNA 1 (FOXD3-AS1) functions as an oncogenic regulator in several types of cancer, including breast cancer, glioma and cervical cancer. However, the effects and mechanisms underlying FOXD3-AS1 in cervical cancer (CC) are not completely understood. The present study aimed to investigate the biological functions and potential molecular mechanisms underlying FOXD3-AS1 in CC progression. Reverse transcription-quantitative PCR was performed to detect FOXD3-AS1, microRNA (miR)-128-3p and LIM domain kinase 1 (LIMK1) expression levels in CC tissues and cells. Immunohistochemical staining and western blotting were conducted to assess LIMK1 protein expression levels in CC tissues and cells, respectively. Cell Counting Kit-8 and BrdU assays were used to determine the role of FOXD3-AS1 in regulating cell proliferation. CC cell migration and invasion were assessed by performing Transwell assays. Dual-luciferase reporter assays were conducted to verify the binding between miR-128-3p and FOXD3-AS1. FOXD3-AS1 expression was significantly increased in CC tissues and cell lines compared with adjacent healthy tissues and normal cervical epithelial cells, respectively. High FOXD3-AS1 expression was significantly associated with poor differentiation of tumor tissues, increased tumor size and positive lymph node metastasis. FOXD3-AS1 overexpression significantly increased CC cell proliferation, migration and invasion compared with the negative control (NC) group, whereas FOXD3-AS1 knockdown resulted in the opposite effects compared with the small interfering RNA-NC group. Moreover, the results demonstrated that FOXD3-AS1 targeted and negatively regulated miR-128-3p, which indirectly upregulated LIMK1 expression. Therefore, the present study demonstrated that FOXD3-AS1 upregulated LIMK1 expression via competitively sponging miR-128-3p in CC cells, promoting CC progression.