BackgroundTriple-negative breast cancer (TNBC) is highly invasive and aggressive and lacks specific molecular targets to improve the prognosis. MiR-25-3p promotes proliferation of many tumors and its role and underlying mechanisms in TNBC remain to be well elucidated.MethodsDifferential expression of miR-25-3p in TNBC was measured with quantitative real-time PCR (qRT-PCR) in both TNBC tissues and cell lines and was validated in the Cancer Genome Atlas (TCGA) database. The effects of miR-25-3p on proliferation, apoptosis capacity of TNBC were evaluated using Cell counting kit-8 (CCK-8), colony formation assay and Annexin V-FITC/PI analyses. The tumor growth in vivo was observed in xenograft model. Luciferase reporter assay, qPCR and western blot were performed to validate a potential target of miR-25-3p in TNBC. Involvement of the AKT and MAPK pathways was investigated by western blot.ResultsMiR-25-3p was found to be upregulated in TNBC in tissues and cell lines. MiR-25-3p promoted TNBC cell proliferation in vitro and tumor growth in xenograft model, while suppression of miR-25-3p induced cell apoptosis. The luciferase reporter assay confirmed that B-cell translocation gene 2 (BTG2) might be a direct target of miR-25-3p, and its expression was negatively regulated by miR-25-3p. Moreover, inhibition of BTG2 expression accounted for the role of miR-25-3p in TNBC. Furthermore, BTG2 suppression might indirectly activate the AKT and ERK-MAPK signaling pathways to mediate the downstream effects of miR-25-3p.ConclusionsThis study demonstrates that miR-25-3p promotes proliferation by targeting tumor suppressor BTG2 and may identify new diagnostic and therapeutic targets in TNBC.Electronic supplementary materialThe online version of this article (10.1186/s12943-017-0754-0) contains supplementary material, which is available to authorized users.

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Purpose: erbB2, the product of the Her2-neu gene, is a well-established therapeutic target for antibody-based biologicals, but anti-erbB2 antibody-toxin fusion proteins are limited in their activity. The goal of this study was to determine if genetically adding an sFv targeting epithelial cell adhesion molecule (EpCAM) to an anti-Her2 sFv immunotoxin would result in enhanced antitumor activity. Experimental Design: In vitro studies were done in which the new bispecific immunotoxin DTEpCAM23 was compared with monospecific immunotoxins (DTEpCAM and DT23) to quantitate immunotoxin activity. Mixtures of monospecific immunotoxins were tested to determine if they were as effective as the bispecific immunotoxin. Binding and internalization studies were also done. In vivo, bispecific immunotoxins were given i.t. to athymic nude mice bearing HT-29 human colon cancer flank tumors and i.p. to mice with i.p. tumors. Results: DTEpCAM23 bispecific immunotoxins showed far greater activity than monospecific immunotoxin (sometimes over 2,000-fold) against most tumor lines. Bispecific immunotoxin was superior and selective in its activity against different carcinoma cell lines. Bispecific immunotoxin had greater activity than monospecific immunotoxin indicating an advantage of having both sFv on the same single-chain molecule. Binding and internalization studies did not explain the differences between bispecific immunotoxin and monospecific immunotoxin activity. Orientation of the sFvs on the molecule had a significant effect on in vitro and in vivo properties. The bispecific immunotoxins were more effective than the monospecific immunotoxin in the flank tumor mouse model. Conclusions: The synthesis of bispecific immunotoxin created a new biological agent with superior in vitro and in vivo activity (over monospecific immunotoxin), more broad reactivity, more efficacy against tumors in vivo, and diminished toxic effects in mice.

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Edited by Charles SamuelRNase BN, the RNase Z family member in E. coli, can participate in the processing of tRNA precursors. However, this function only becomes apparent when other processing enzymes are absent, raising the question of its primary physiological role. Here, we show that RNase BN itself is subject to growth phasedependent regulation, because both rbn mRNA and RNase BN protein are at their highest levels in early exponential phase, but then decrease dramatically and are essentially absent in stationary phase. As a consequence of this variation, certain small RNAs, such as 6S RNA, remain low in exponential phase cells, and increase greatly in stationary phase. RNase BN affects 6S RNA abundance by decreasing its stability in exponential phase. RNase BN levels increase rapidly as cells exit stationary phase and are primarily responsible for the decrease in 6S RNA that accompanies this process. Purified RNase BN directly cleaves 6S RNA as shown by in vitro assays, and the 6S RNA:pRNA duplex is an even more favorable substrate of RNase BN. The exoribonuclease activity of RNase BN is unnecessary because all its action on 6S RNA is due to endonucleolytic cleavages. These data indicate that RNase BN plays an important role in determining levels of the global transcription regulator, 6S RNA, throughout the growth cycle.The RNase Z family of enzymes is widespread among organisms from prokaryotes to eukaryotes. These RNases generally participate in the 3Ј processing of tRNA precursors lacking an encoded CCA sequence, cleaving right after the discriminator nucleotide to generate a substrate for CCA addition by tRNA nucleotidyltransferase (1). In addition to tRNA precursors, some mRNAs have also been identified as substrates including some in rice (2) and Escherichia coli (3), raising the possibility of other putative substrates (4). This is of particular significance in E. coli, because the precursors of all 86 tRNAs already contain the CCA trinucleotide (5), obviating a need for the action of RNase Z.The RNase Z family member in E. coli is termed RNase BN and was originally identified as an enzyme required for maturation of those bacteriophage T4 tRNA precursors that lacked a CCA sequence (6, 7). In contrast to RNase Z in most organisms, RNase BN can act as an exoribonuclease or an endoribonuclease (8, 9). When acting on CCA-containing tRNA precursors, RNase BN cleaves after the CCA sequence using its endoribonuclease activity or trims up to the CCA sequence using its exoribonuclease activity, keeping the CCA sequence intact (10). Although both activities of RNase BN can function in vivo (9), a role for this enzyme in maturation of tRNA precursors only becomes evident when other processing ribonucleases are inactivated (11), suggesting that its primary function in wild type E. coli cells is still unknown.Ribonucleases play an important role in cellular RNA metabolism, and recent studies have revealed that these enzymes may act as important regulators of small RNAs (sRNAs) 2 by participating in their maturati...

Background Vascular remodeling is the most critical pathogenesis of atherosclerosis. Adipokine chemerin was known for its relationship with obesity as well as metabolism. Most recently, chemerin was found to play a crucial role in the pathologic process of cardiovascular diseases including coronary heart disease. In this study, we surveyed the role of chemerin in progression of atherosclerosis in ApoE−/− mice. Objective To investigate the relationship between chemerin and progression of atherosclerosis in ApoE−/− mice and its mechanism. Methods 8-week-old ApoE−/− mice were fed with high-fat diet to induce the atherosclerosis model. Adenoviruses were transfected for knockdown or overexpression of chemerin gene into aorta. Serums and aortic tissues of ApoE−/− mice were obtained after feeding high-fat diet for 16 weeks. HE staining and oil red staining were performed to evaluate aortic plaque. ELISA was performed to explore serum levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and transforming growth factor-β1 (TGF-β1). Real-time PCR and western blotting were carried out to investigate the mRNA and protein levels of chemerin, nuclear factor-κB p65 (NF-κBp65), proliferating cell nuclear antigen (PCNA), phosphorylated p38 mitogen-activated protein kinase (p-p38-MAPK), phosphorylated c-Jun N-terminal kinase (p-JNK), and phosphorylated extracellular signal regulated kinase 1/2 (p-ERK 1/2). Result Aortic plaque formation was significantly induced by high-fat diet in ApoE−/− mice. Simultaneously, elevated serum levels of TNF-α and IL-1β and elevated mRNA and protein levels of chemerin, NF-κBp65, PCNA, p-p38-MAPK, p-JNK, and p-ERK 1/2 were found in ApoE−/− mice. After aortic chemerin gene was inhibited by adenovirus, aortic atherosclerosis induced by high-fat diet was significantly meliorated, serum levels of TNF-α and IL-1β decreased, mRNA and protein levels of NF-κBp65, PCNA, p-p38-MAPK, p-JNK, and p-ERK 1/2 decreased simultaneously. Conclusion Our study revealed that chemerin stimulated the progression of atherosclerosis in ApoE−/− mice.

Edited by Karin Musier-ForsythRNase BN, the Escherichia coli RNase Z family member, plays a limited role in tRNA metabolism, in contrast to most other organisms. However, RNase BN does act on 6S RNA, the global transcription regulator, degrading it in exponential-phase cells and maintaining it at low levels during this phase of growth. RNase BN levels decrease in stationary-phase cells, leading to elevation of 6S RNA and subsequent regulation of RNA polymerase. These findings were the first indication that RNase BN itself is growth phase-regulated. Here, we analyze the mechanism of this regulation of RNase BN. We find that RNase BN decreases in stationary phase because its mRNA becomes unstable, due primarily to its degradation by RNase E. However, in exponential-phase cells rbn mRNA is stabilized due to binding by the sRNA, GcvB, and the protein, Hfq, which reduce cleavage by RNase E. Because the amount of GcvB decreases in stationary phase, rbn mRNA is less protected and becomes increasingly unstable resulting in reduction in the amount of RNase BN. The small RNA-dependent, positive regulation of RNase BN in exponential-phase cells is the first example of this novel mechanism for RNase regulation.

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