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Objective To study the role and mechanism of trans-activation response RNA-binding protein 2 (TARBP2) in post-transcriptional regulation of the expression of AKAP12, a metastasis suppressor gene, in breast cancer cells. Methods The expression of TARBP2 in breast tumor tissues and potential relationship between TARBP2 expression and tumor metastasis were analyzed by bioinformatics methods. Bioinformatics methods were used to analyze the correlation between TARBP2 and AKAP12 expression in different breast cancer datasets. MDA-MB-231 cells were transfected with GFP-tagged TARBP2 plasmids by Lipofectamine 2000 and screening with G418. Lung metastasis in tumor-bearing nude mice was detected by HE staining. RT-qPCR was used to test the expression of AKAP12 and its half-life. Luciferase assay was carried out to determine whether the transcript decay was mediated through targeting the 3′UTR. EMSA assay was performed to detect the physically binding of TARBP2 with stem-loop structure of AKAP12. Results The high expression of TARBP2 in human breast tumor tissue was closely related to lymph node metastasis. TARBP2 over-expression in MDA-MB-231 cells significantly promoted tumor metastasis in vitro(P＜0.05). TARBP2 inhibited the expression of AKAP12(P＜0.01) and reduced its mRNA half-life(P＜0.05). TARBP2 significantly suppressed luciferase activity of AKAP12 3′UTR reporter(P＜0.05) and bound to the stem-loop structure. There was a significant negative correlation between TARBP2 and AKAP12 expression in human breast cancer samples(P＜0.001). Conclusions TARBP2-mediated inhibition of AKAP12 gene expression might be one of the mechanisms of TARBP2 promoting breast cancer metastasis.

Matrix metalloproteinases (MMPs) have been involved in inflammatory and degradative processes in pathologic conditions. The purpose of this study was to investigate the protective effect of melatonin in human umbilical vein endothelial cell (HUVEC) monolayer permeability and the regulation of MMP9 induced by interleukin 1&bgr; (IL1&bgr; (IL1B)) in HUVECs. Protection studies were carried out with melatonin, a well-known antioxidant and antiinflammatory molecule. MMP9 expression was increased with IL1&bgr; induction in HUVECs. Melatonin showed a barrier-protective role by downregulation of MMP9 and upregulation of tissue inhibitor of metalloproteinase-1 expression in HUVECs. Meanwhile, melatonin also decreased sodium fluorescein permeability and counteracted the downregulation of vascular endothelial cadherin and occludin expression in HUVECs. During inflammatory stimulus, nuclear factor-kB (NF-kB) plays a significant role in regulating MMP genes expression, thus the function of NF-kB in HUVECs' barrier disruption was investigated. IL1&bgr; induced nuclear translocation of NF-kB in HUVECs and regulated MMP9 expression. However, NF-kB translocation into the nucleus was inhibited significantly by melatonin. Our results show that melatonin decreases the permeability of monolayer endothelial cell induced by IL1&bgr;. At the same time, melatonin decreased the expression and activity of MMP9 by a NF-kB-dependent pathway in HUVECs induced by IL1&bgr;. [ABSTRACT FROM AUTHOR]

Background: Asthmatic and allergic inflammation is mediated by T H 2 cytokines (IL-4, IL-5, and IL-13). Although we have learned much about how T H 2 cells are differentiated, the T H 2 checkpoint mechanisms remain elusive., Objectives: In this study we investigate how monocyte chemotactic protein-induced protein 1 (MCPIP1; encoded by the Zc3h12a gene) regulates IL-5-producing T H 2 cell differentiation and T H 2-mediated inflammation., Methods: The functions of Zc3h12a -/- CD4 T cells were evaluated by checking the expression of T H 2 cytokines and transcription factors in vivo and in vitro. Allergic airway inflammation of Zc3h12a -/- mice was examined with murine asthma models. In addition, antigen-specific CD4 T cells deficient in MCPIP1 were transferred to wild-type recipient mice, challenged with ovalbumin (OVA) or house dust mite (HDM), and accessed for T H 2 inflammation., Results: Zc3h12a -/- mice have spontaneous severe lung inflammation, with an increase in mainly IL-5- and IL-13-producing but not IL-4-producing T H 2 cells in the lung. Mechanistically, differentiation of IL-5-producing Zc3h12a -/- T H 2 cells is mediated through Notch signaling and Gata3 independent of IL-4. Gata3 mRNA is stabilized in Zc3h12a -/- T H 2 cells. MCPIP1 promotes Gata3 mRNA decay through the RNase domain. Furthermore, deletion of MCPIP1 in OVA- or HDM-specific T cells leads to significantly increased T H 2-mediated airway inflammation in OVA or HDM murine models of asthma., Conclusions: Our study reveals that MCPIP1 regulates the development and function of IL-5-producing T H 2 cells through the Notch/Gata3 pathway. MCPIP1 represents a new and promising target for the treatment of asthma and other T H 2-mediated diseases., (Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)