BACKGROUND:MicroRNAs (miRNAs) are key regulators of many cellular pathways. However, the picture for components or regulators involved in the process of miRNA biogenesis and function remains to be further elucidated. Early growth response gene 1 (Egr1) has long been considered as tumor suppressor and transcriptional factor involved in cell proliferation and regulation of apoptosis. RESULTS:Here we show that Egr1 is able to modulate guide strand loading of certain miRNAs or siRNAs in human HEK293 and A549 cells, which is related with thermodynamic parameters of miRNA or siRNA. Further, we found that Egr1 modulates the silencing activity of miR-125a-3p in vivo. Immunoprecipitation experiment demonstrated that Egr1 could bind miRNA biogenesis protein TAR RNA-binding protein2 (TRBP2), and knockdown TRBP by RNAi abolished the regulating effects of Egr1 on miR-125a-3p efficiency. Further experiments revealed that deleting sequence 97-227aa containing dsRBD B domain of TRBP eliminated the binding phenomenon between Egr1 and TRBP and impaired the effect of Egr1 on miR-125a-3p efficiency. CONCLUSIONS:Taken together, our study has demonstrated that Egr1 is able to regulate miRNA activity of miR-125a-3p in human cells through binding TRBP, which highlights an unexpected function of Egr1 in miRNA pathway.

Compelling evidence indicates that stress in utero, as manifested by low birth weight (LBW), increases the risk of metabolic syndrome in adulthood. Singletons conceived by assisted reproductive technology (ART) display a significant increase in LBW risk and ART offspring have a different metabolic profile starting at birth. Here, used mouse as a model, we found that ART resulted in reduced fetal weight and placental overgrowth at embryonic day 18.5 (E18.5). The ART placentae exhibited histomorphological alterations with defects in placental layer segregation and glycogen cells migration at E18.5. Further, ART treatments resulted in downregulation of a majority of placental nutrient transporters and reduction in placental efficiency. Moreover, the ART placentae were associated with increased methylation levels at imprinting control regions of H19, KvDMR1 and disrupted expression of a majority of imprinted genes important for placental development and function at E18.5. Our results from the mouse model show the first piece of evidence that ART treatment could affect fetal growth by disrupting placental development and function, suggests that perturbation of genomic imprinting resulted from embryo manipulation may contribute to these problems.

MicroRNAs (miRNAs) are closely associated with cell proliferation, invasion and metastasis in various types of cancer, including prostate cancer. In this study, the role of miR-429 in the regulation of cell proliferation was investigated in prostate cancer cells. miR-429 expression levels were measured in the IF11 and IA8 prostate cancer cell lines and normal prostate epithelial tissues by quantitative polymerase chain reaction. miR-429 mimics or an miR-429 inhibitor were then transfected into the human prostate cancer cell lines. MTT and fluorescence-activated cell sorting were used to detect the effect of miR-429 on cell proliferation. A luciferase reporter system was employed to verify the potential target of miR-429. The results revealed that miR-429 was significantly upregulated in the human prostate cancer cell lines, compared with the normal prostate epithelial tissue. Downregulation of miR-429 expression in IF11 and IA8 cells inhibited cell proliferation and arrested the cells in the G1 phase of the cell cycle. The luciferase assay demonstrated that p27Kip1 was a direct target of miR-429. Furthermore, overexpression of p27Kip1 was observed to partially rescue the proliferation‑promoting effect of miR-429 on IA8 cells. In conclusion, to the best of our knowledge this study was the first to show that miR-429 is involved in the oncogenesis of prostate cancer and thus may be a novel prognostic biomarker in prostate cancer.

目的 探讨miR-140-3p与人肺腺癌A549细胞顺铂药物敏感性的关系.方法 化学合成miR-140-3p mimics及inhibitor,脂质体2000介导其转染入人肺腺癌A549细胞,利用荧光定量PCR方法观察转染细胞中miR-140-3p表达水平的变化;噻唑蓝(MTT)法检测A549细胞对顺铂作用的敏感性.结果 转染miR-140-3p mimics/inhibitor可分别升高(约30%)或降低(约30%)人肺腺癌A549细胞中miR-140-3p表达;同时,与对照组相比,转染miR-140-3p inhibitor的人肺腺癌A549细胞对顺铂药物作用的敏感度显著增加,细胞增殖速率降低33%(P<0.05);而转染miR-140-3p mimics的A549细胞对顺铂药物作用的敏感度显著降低,细胞增殖速率升高32%(P<0.05).结论 miR-140-3p的表达水平与人肺腺癌A549细胞对顺铂药物的敏感度呈负相关,提示miR-140-3p可能在A549细胞顺铂耐药过程中发挥重要作用.

AIM:To observe the effects of sargentgloryvine stem extracts (SSE) on the hepatoma cell line HepG-2 in vitro and in vivo and determine its mechanisms of action. METHODS:Cultured HepG-2 cells treated with SSE were analysed by 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-Diphenyltetrazolium bromide and clone formation assay. The cell cycle and apoptosis analysis were conducted by flow cytometric, TdT-Mediated dUTP Nick End Labeling and acridine orange/ethidium bromide staining methods, and protein expression was examined by both reverse transcriptase-polymerase chain reaction and Western blotting. The pathological changes of the tumor cells were observed by haematoxylin and eosin staining. Tumor growth inhibition and side effects were determined in a xenograft mouse model. RESULTS:SSE treatment could not only inhibit HepG-2 cell proliferation in a dose- and time-dependent manner but also induce apoptosis and cell cycle arrest at the S phase. The number of colonies formed by SSE-treated tumor cells was fewer than that of the controls (P < 0.05). SSE induced caspase-dependent apoptosis accompanied by a significant decrease in Bcl-xl and Mcl-1 and elevation of Bak expression (P < 0.05). Tumor necrosis factor α in the xenograft tumor tissue and the liver functions of SSE-treated mice showed no significant changes at week 8 compared with the control group (P > 0.05). Systemic administration of SSE could inhibit the HepG-2 xenograft tumor growth with no obvious toxic side effects on normal tissues. CONCLUSION:SSE can induce apoptosis of HepG-2 cells in vitro and in vivo through decreasing expression of Bcl-xl and Mcl-1 and increasing expression of Bax.