Background: The NuRD complex controls gene expression through altering chromatin structure.Results: The MTA1-RbAp48 structure shows how the RbAp46/p48 histone chaperones are recruited to NuRD.Conclusion: The MTA subunits act as scaffolds for NuRD complex assembly.Significance: The MTA/RbAp48 interaction prevents binding of histone H4, which is crucial for understanding the role of the RbAp46/p48 chaperones in the complex.

Polyethylenimine (PEI) is a class of cationic polymers proven to be effective for gene delivery. However, PEI is nondegradable and the molecular weight of PEI affects the cytotoxicity and gene transfer activity. Aiming to prepare a biodegradable gene vector with high transfection efficiency and low cytotoxicity, we conjugated low molecular weight (LMW) PEIs to the biodegradable backbone polyglutamic acids derivative (PEG-b-PBLG) by aminolysis to form PEIs combined PEG-b-PLG-g-PEIs (GGI). Two copolymers, GGI 30 and GGI 40, were synthesized. The chemistry of GGI was characterized using IR, 1H NMR and 13C NMR, GPC, and CD, respectively. The degradation behaviors of copolymer GGI in papain solution were investigated. GGIs showed good DNA condensation ability and high protection of DNA from nuclease degradation. The zeta potential of the GGI/pDNA polyplexes was approximately 15 mV, and the particle size was in the range 102-138 nm at N/P ratios between 10 and 30. The particle size and the morphology of the polyplex was further confirmed by transmission electron microscope (TEM). In cytotoxicity assay, GGIs were significantly less toxic than PEI 25k. The degradation product of GGI exhibited negligible effects on cells even at high copolymer concentration. The results of GFP flow cytometry and fluorescence imaging showed that the trasnfection efficiencies of GGIs were all markedly higher than PEI 25k in Hela, HepG2, Bel 7402, and 293 cell lines. Importantly, the presence of serum had a lower inhibitive effect on the transfection activity of GGI in comparison to PEI 25k and Lipofectamine 2000. Therefore, PEG-b-PLG-g-PEI copolymers may be attractive cationic polymers for nonviral gene therapy.

The nucleosome remodeling deacetylase (NuRD) complex is a highly conserved regulator of chromatin structure and transcription. Structural studies have shed light on this and other chromatin modifying machines, but much less is known about how they assemble and whether stable and functional sub-modules exist that retain enzymatic activity. Purification of the endogenous Drosophila NuRD complex shows that it consists of a stable core of subunits, while others, in particular the chromatin remodeler CHD4, associate transiently. To dissect the assembly and activity of NuRD, we systematically produced all possible combinations of different components using the MultiBac system, and determined their activity and biophysical properties. We carried out single-molecule imaging of CHD4 in live mouse embryonic stem cells, in the presence and absence of one of core components (MBD3), to show how the core deacetylase and chromatin-remodeling sub-modules associate in vivo. Our experiments suggest a pathway for the assembly of NuRD via preformed and active sub-modules. These retain enzymatic activity and are present in both the nucleus and the cytosol, an outcome with important implications for understanding NuRD function.

The NuRD (nucleosome remodeling and deacetylase) complex serves as a crucial epigenetic regulator of cell differentiation, proliferation, and hematopoietic development by coupling the deacetylation and demethylation of histones, nucleosome mobilization, and the recruitment of transcription factors. The core nucleosome remodeling function of the mammalian NuRD complex is executed by the helicase-domain-containing ATPase CHD4 (Mi-2β) subunit, which also contains N-terminal plant homeodomain (PHD) and chromo domains. The mode of regulation of chromatin remodeling by CHD4 is not well understood, nor is the role of its PHD and chromo domains. Here, we use small-angle X-ray scattering, nucleosome binding ATPase and remodeling assays, limited proteolysis, cross-linking, and tandem mass spectrometry to propose a three-dimensional structural model describing the overall shape and domain interactions of CHD4 and discuss the relevance of these for regulating the remodeling of chromatin by the NuRD complex.

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Tamoxifen resistance remains to be a huge obstacle in the treatment of hormone-dependent breast cancer, and this therefore highlights the dire need to explore the underlying mechanisms. The epithelial-mesenchymal transition (EMT) is a molecular process through which an epithelial cell transfers into a mesenchymal phenotype. Roles of EMT in embryo development, cancer invasion and metastasis have been extensively reported. Herein, we established tamoxifen-resistant MCF-7/TR breast cancer cells and showed that MCF-7/TR cells underwent EMT driven by enhanced endogenous TGF-β/Smad signaling. Ectopic supplement of TGF-β promoted in MCF-7 cells a mesenchymal and resistant phenotype. In parallel, we demonstrated that resveratrol was capable of synergizing with tamoxifen and triggering apoptosis in MCF-7/TR cells. Further Western blot analysis indicated that the chemosensitizing effects of resveratrol were conferred with its modulation on endogenous TGF-β production and Smad phosphorylation. In particular, 50 μM resveratrol had minor effects on MCF-7/TR cell proliferation, but could significantly attenuate endogenous TGF-β production and the Smad pathway, ultimately leading to reversion of EMT. Collectively, our study highlighted distinct roles of EMT in tamoxifen resistance and resveratrol as a potential agent to overcome acquired tamoxifen resistance. The molecular mechanism of resveratrol chemosensitizing effects is, at least in part, TGF-β/Smad-dependent.

Background/Aims: Increasing evidence demonstrates that long non-coding RNAs (lncRNAs) regulate diverse cellular processes and cancer progression. Whether lncRNAs play any functional role in colorectal carcinoma (CRC) remains largely unknown. The aim of this study was to investigate the role of lncRNA CPS1 intronic transcript 1 (CPS1-IT1) in CRC. Methods: Expression of CPS1-IT1 was initially assessed in human CRC tissues and in a series of CRC cell lines. The correlations between CPS1-IT1 levels and survival outcomes were analyzed to elucidate the clinical significance of CPS1-IT1 in CRC. The underlying mechanisms of CPS1-IT1 in CRC were analyzed through in vitro and in vivo functional assays. Results: Expression of CPS1-IT1 was significantly decreased in CRC tissues and cell lines, and patients with low CPS1-IT1 expression had poor survival outcomes. The results of in vitro assays revealed that CPS1-IT1 significantly reduced cell proliferation, migration and invasion capacities and accelerated cell apoptosis, thereby suppressing epithelial-mesenchymal transition (EMT). An in vivo animal model also demonstrated the tumor-suppressive role of CPS1-IT1. Conclusion: In this study, we found that CPS1-IT1 has a tumor-suppressive role in CRC. Our data suggest that CPS1-IT1 could be used as a new prognostic biomarker and therapeutic target for CRC.

High circulating HOTAIR level correlates with less response to neoadjuvant chemotherapy as well as a worse prognosis in breast cancer patients. Therefore, the present study provides a favorable basis to use circulating HOTAIR as a predictor of neoadjuvant chemotherapy response.