Dnmt3a is required for the tumor stemness of B16 melanoma cells

The relationship of carcinogenesis and DNA methyltransferases has attracted extensive attention in tumor research. We reported previously that inhibition of de novo DNA methyltransferase 3a (Dnmt3a) in murine B16 melanoma cells significantly suppressed tumor growth and metastasis in xenografted mouse model. Here, we further demonstrated that knockdown of Dnmt3a enhanced the proliferation in anchor-independent conditions of B16 cells, but severely disrupted its multipotent differentiation capacity in vitro. Furthermore, transforming growth factor β1, a key trigger in stem cell differentiation and tumor cell epithelial-mesenchymal transition (EMT), mainly induced apoptosis, but not EMT in Dnmt3a-deficient B16 cells. These data suggested that Dnmt3a is required for maintaining the tumor stemness of B16 cells and it assists B16 cells to escape from death during cell differentiation. Thus it is hypothesized that not only extraordinary self-renewal ability, but also the capacity of multipotent differentiation is necessary for the melanoma tumorigenesis. Inhibition of multipotent differentiation of tumor cells may shed light on the tumor treatment.

[Corrigendum] Alterations in gene expression during sexual differentiation in androgen receptor knockout mice induced by environmental endocrine disruptors

Following the publication of the above article, an interested reader drew to our attention a number of issues and concerns related to the descriptions of the genes and mouse models in the above paper. After having consulted with the authors, they have acknowledged that their paper did indeed contain a number of errors, and these are listed below in this Corrigendum. First, the authors realized that an incorrect figure was included as Fig. 1 in the paper. The correct (and entirely different) version of Fig. 1, together with its figure legend, is shown opposite. The following textual errors in the paper should also be noted: i) In the Abstract, lines 3‑4 in the left‑hand column (LHC): "androgen receptor (AR)‑/‑, AR+/‑ and AR+/+ male mice" should have been written as "androgen receptor (AR) conditional knockout mice"; line 5 in the LHC: "flox‑AR" should have been written as "ARflox/+"; line 6 in the LHC: "AR‑Cre" should have been written as "Amhr2‑Cre"; line 22 in the LHC: "AR+/‑" should have been written as "ARflox/Y"; line 1 in the right‑hand column (RHC): "heterozygous" should have been written as "ARflox/Y"; and line 2 in the RHC, "heterozygous" should have been written as "ARflox/Y Cre+". ii) In the Introduction, paragraph 3, lines 6‑7 in the LHC: "or female ARKO mice" should have been deleted; paragraph 4, line 5 in the LHC: "AR‑/‑", "AR+/‑" and "AR+/+" should have been deleted; paragraph 4, line 11 in the LHC: "AR‑/‑", and "AR+/‑" should have been written as "AR‑/Y", whereas "AR+/+" should have been written as "AR+/Y". iii) In the Materials and methods, paragraph 3, the last sentence in the RHC {"The identification of the plasmid containing leydig cells expressing Cre recombinant enzyme and the specificity of the genetically modified (gm) sequence [Amhr2‑Cre (7.1)] are shown in Fig. 1} should have been written as "The positive clones were identified by digestion and sequencing." iv) In the Results, the first subheading in the RHC ("...transgenic mouse model (Amhr2‑Cre)" should have been written as "...AR conditional knockout targeting vector"; paragraph 1, lines 1‑3 in the RHC: The sentence "The AR gene condition knockout plasmid was identified and confirmed by enzyme digestion with BamHI" should have been written as "The AR gene conditional knockout strategy is shown in Fig. 1. The gene targeting vector was identified and confirmed by enzyme digestion with BamHI"; paragraph 1, line 4 in the RHC: "2.7 kb" should have been written as "7.8 kb"; Table III, in the title and in the Table heading, "AR+/‑" should have been written as "AR+/Y", and "AR‑/‑" should have been written as "AR‑/Y"; in the subheading "Comparison between AR‑/‑ male mice and normal mice", "AR‑/‑" should have been written as "AR‑/Y", and "normal" should have been written as "AR+/Y"; and paragraph 4, lines 3‑5 in the LHC: "AR+/‑" should have been written as "AR+/Y", and "AR‑/‑" should have been written as "AR‑/Y". All the authors thank the interested reader for drawing these matters to their attention, and agree to the contents of this Corrigendum. The authors also stress that these errors did not significantly influence either the results or the conclusions of the paper. Furthermore, the authors apologize to the Editor of International Journal of Molecular Medicine and to the readership for any inconvenience caused. [the original article was published in International Journal of Molecular Medicine 35: 399‑404, 2015; DOI: 10.3892/ijmm.2014.2015].

Poly(amino acid)/ZnO/mesoporous silica nanoparticle based complex drug delivery system with a charge-reversal property for cancer therapy

Negative-to-positive charge-reversal strategy employed in anti-cancer drug delivery systems (DDSs) can improve the utilization of the drugs as well as reduce their side effects efficiently. In this article, a complex DDS named DOX@MSN-ZnO-PLL-PLL(DMA) was prepared. Doxorubicin hydrochloride (DOX) was loaded in mesoporous silica nanoparticles (MSNs), which were then covered by ZnO in situ. Poly-_L-lysine (PLL) and 2,3-dimethylmaleic anhydride functionalized PLL (PLL(DMA)) were finally coated on the nanoparticles through a Layer-by-Layer (LbL) assembly process with PLL(DMA) outside to obtain the carriers. The negative charged PLL(DMA) avoided the unspecific uptake of the carriers by normal cells at pH 7.4. While the charge-reversal property could reverse the zeta-potential of the carriers to positive in weakly acidic tumor tissues at pH 6.5, which promoted the cytophagy of the carriers by cancer cells. ZnO which blocked the pores of MSNs could be dissolved intracellular due to the more acidic environment in endosome/lysosome, and resulting in drug release for cancer cell apoptosis. Zeta-potential measurements, the in vitro cellular uptake behaviors as well as cellular cytotoxicity of the carriers at different pH values were investigated to prove the charge-reversal property. The in vitro drug release studies and the cellular cytotoxicity studies were also investigated to prove the controlled DOX release behavior of the carriers. In summary, the complex DDS with charge-reversal property should be of consideration in cancer therapy.

A microRNA expression signature as a predictor of survival for colon adenocarcinoma

Colon cancer is a major cause of cancer mortality worldwide and most colon cancers are adenocarcinoma. MicroRNA (miRNA) expression signature has been shown to be able to predict progression and prognosis of various cancers. The aim of our study was to explore a novel signature of microRNA expression for predicting survival of colon adenocarcinoma patients. By analyzing the miRNA expression profiles and clinical information of 329 colon adenocarcinoma patients derived from The Cancer Genome Atlas database. 129 miRNAs were identified to be expressed differentially between the cancer and adjacent tissues. Among them, 27 miRNAs were found to be associated with the corresponding clinical characteristics of the patients. Furthermore, 7 miRNAs (let-7a-2, mir-32, mir-181a-1, mir-197, mir-328, mir-505 and mir-652) were found to be significantly correlated with the patient survival. The risk established by the 7-miRNA signature we built was proved be an independent prognostic factor (Hazard ratio [HR] = 2.048; 95% CI = 1.144-3.664; p, 0.016). In summary, our study identified miRNAs correlated with progression and prognosis of colon adenocarcinoma and built a 7-microRNA expression signature for prediction of the survival of the patients with colon adenocarcinoma.

Cytotoxic effect of oxaloacetate on HepG2-human hepatic carcinoma cells via apoptosis and ROS accumulation

Oxaloacetate (OA) is one of the intermediates of the Krebs cycle. In addition to its role in energy production, OA may have other effects on the cell. We report here that OA could have a cell type dependent cytotoxic effect on the human hepatic carcinoma cell line HepG2 through induction of apoptosis and reactive oxygen species (ROS) accumulation. In our study, OA decreased the viability and colony formation of HepG2 cells and induced cell death. Caspase-3 activity was increased, the pro-apoptotic protein Bax was up-regulated, and the anti-apoptotic protein Bcl-2 was down-regulated in OA-treated HepG2 cells indicating that apoptosis through the intrinsic pathway was involved in the cell death. The ROS level in OA-treated HepG2 cells was increased. The anti-oxidant N-acetylcysteine (NAC) and glutathione (GSH) prevented the OA-induced decrease in cell but did not alter the enhanced apoptotic Bax/Bcl-2 mRNA ratio. These results suggest that the OA-induced apoptosis of HepG2 cell is not driven by oxidative damage and at least two distinct mechanisms, one mediated by ROS and one involving apoptosis, result in the cytotoxic effects of OA on HepG2 cells. These studies expand the biological functional repertoire of OA and provide a mechanism by which hepatocellular carcinoma may be targeted by OA.

An AIE-active theranostic probe for light-up detection of Aβ aggregates and protection of neuronal cells

An AIE-active probe of Cur-N-BF₂ is developed for light-up detection of Aβ fibrils and plaques, inhibition of Aβ fibrillation, disassembly of preformed Aβ fibrils, and protection of neuronal cells.

Integrated holographic waveguide display system with a common optical path for visible and infrared light

We propose an integrated holographic waveguide display system. An infrared volume holographic grating (IVHG) and a visible light grating are recorded on the same waveguide to achieve the purpose of a common light path for system miniaturization. Simulated and experimental results verify the feasibility of this method. The coupling efficiencies of the infrared module for eye tracking and the visible light module for augmented reality (AR) display are 40% and 45%. The holographic waveguide has a weight of only 4.3 grams. It is believed that this technique is a good way to achieve a light and thin eye tracking near-eye display.

[Concentrations and pollution assessment of mercury in farmland soil of Xinqiao Mining Area of Tongling, Anhui, China.]

To investigate the effects of mining activities on mercury (Hg) enrichment in farmland soil, soil samples were collected from four villages (Xinjian Village, Yehu Village, Xinhu Village and Hucheng Village) in the vicinity of Xinqiao Mining Area, Tongling. Hg concentration was measured by atomic fluorescence spectrophotometer. The geo-accumulation index was used to evaluate the Hg pollution level of the soils. The results showed that average concentration of total Hg in farmland soil was (0.137±0.078) mg·kg^-1, which exceeded the background value of soil Hg in Tongling area. The average concentration of Hg in four villages followed the order of Xinjian Village (0.221 mg·kg^-1)>Xinhu Village (0.118 mg·kg^-1)>Yehu Village(0.115 mg·kg^-1)>Hucheng Village (0.096 mg·kg^-1). Moreover, the average Hg concentration of different forms in Xinjian Village followed the order of residue (0.036 mg·kg^-1) > alkali soluble (0.031 mg·kg^-1) > hydrogen peroxide soluble (0.022 mg·kg^-1)> acid soluble (0.020 mg·kg^-1)> water soluble (0.012 mg·kg^-1). The distance from the mining area was the main factor affecting the distribution of soil Hg concentration in farmlands. The contaminated Xinqiao River, to some degree, had exa-cerbated soil Hg pollution. Soil organic matter affected the accumulation and transformation of total Hg and hydrogen peroxide Hg in the farmlands. The order of the geo-accumulation index followed as Xinjian Village(1.559) >Xinhu Village(0.654) >Yehu Village(0.616) >Hucheng Village(0.356). The pollution level of farmland soil in Xinjian Village belonged to middle level of Hg pollution,which deserved more attention.

Gpr97/Adgrg3 ameliorates experimental autoimmune encephalomyelitis by regulating cytokine expression

Multiple sclerosis and its primary animal model, experimental autoimmune encephalomyelitis (EAE), are inflammatory diseases of the central nervous system (CNS) characterized by immune-mediated demyelination and neurodegeneration that may be mediated by inhibition of the nuclear factor-κB (NF-κB) signaling pathway. Gpr97, encoded by Adgrg3, has been reported to regulate the activity of NF-κB. In this study, using a previously established Adgrg3-knockout mouse model, we investigated the roles of Gpr97 in the development of autoimmune CNS disease in mice. We found a marked increase in the expression of Adgrg3 in spinal cords of mice with EAE. Adgrg3-deficient (Adgrg3-/-) mice with EAE exhibited increases in peak severity and the cumulative disease score compared with littermate controls, followed by a notable increase of leukocyte infiltration and more extensive demyelination. The percentages of Th1/Th17 cells in the CNS were significantly increased in Adgrg3-/- mice and accompanied by high levels of interleukin (IL)-6, interferon-γ, tumor necrosis factor-α, and IL-17. An in vitro culture assay verified that Gpr97 regulated proinflammatory cytokine production. Taken together, our results show that Gpr97 plays an important role in the development of EAE and may have a therapeutic potential for the treatment of CNS autoimmunity.

Rdh13 deficiency weakens carbon tetrachloride-induced liver injury by regulating Spot14 and Cyp2e1 expression levels

Mitochondrion-localized retinol dehydrogenase 13 (Rdh13) is a short-chain dehydrogenase/reductase involved in vitamin A metabolism in both humans and mice. We previously generated Rdh13 knockout mice and showed that Rdh13 deficiency causes severe acute retinal light damage. In this study, considering that Rdh13 is highly expressed in mouse liver, we further evaluated the potential effect of Rdh13 on liver injury induced by carbon tetrachloride (CCl₄). Although Rdh13 deficiency showed no significant effect on liver histology and physiological functions under regular culture, the Rdh13^-/- mice displayed an attenuated response to CCl₄-induced liver injury. Their livers also exhibited less histological changes and contained lower levels of liver-related metabolism enzymes compared with the livers of wild-type (WT) mice. Furthermore, the Rdh13^-/- mice had Rdh13 deficiency and thus their liver cells were protected from apoptosis, and the quantity of their proliferative cells became lower than that in WTafter CCl₄ exposure. The ablation of Rdh13 gene decreased the expression levels of thyroid hormone-inducible nuclear protein 14 (Spot14) and cytochrome P450 (Cyp2e1) in the liver, especially after CCl₄ treatment for 48 h. These data suggested that the alleviated liver damage induced by CCl₄ in Rdh13^-/- mice was caused by Cyp2e1 enzymes, which promoted reductive CCl₄ metabolism by altering the status of thyroxine metabolism. This result further implicated Rdh13 as a potential drug target in preventing chemically induced liver injury.

Stability and digestibility of one- or bi-layered medium-chain triglyceride emulsions with gum Arabic and whey protein isolates by pancreatic lipase in vitro

Interfacial engineering approaches have been used to design functional foods so as to control lipase-induced digestion of emulsified lipids and release of bioactive lipophilic components in the gastrointestinal tract. In this study, emulsion droplets with the interface stabilized with gum Arabic (GA) and whey protein isolate (WPI) were prepared by mixing or sequential adsorption. WPI/GA intramolecular soluble complexes (ISCs) have superior emulsifying properties in stabilizing oil-in-water emulsions. The impact of the interfaces for WPI/GA ISC-layered (one-layered) and double-layered emulsions formed by sequential deposition of WPI or GA on the lipolysis of emulsions was investigated using an in vitro simulated gastrointestinal model. Transglutaminase and dithiothreitol were introduced to crosslink the interfacial proteins and improve the interfacial stability. The ISC-layered emulsion was less stable to aggregation than the double-layered ones in simulated gastric fluid due to dissociation of ISCs caused by the electrostatic screening of ions and proteolysis of interfacial proteins driven by pepsin. The ISC-layered emulsion conferred a significant slower rate and extent of lipid digestion compared to the double-layered emulsions post gastric proteolysis (P < 0.05). It is presumed for the ISC-layered emulsion that the destabilization to aggregation and coalescence within the simulated gastrointestinal fluids and the steric hindrance of the robust and thick interfacial layer might contribute to delaying free fatty acids release. It suggests that both the initial interfacial properties and the stability of the emulsified lipid droplets within the simulated gastrointestinal fluids play an important role in determining the rate and extent of lipid digestion. It is predicted that direct destabilization of emulsified lipids using interfacial engineering approaches has the potential of modifying lipid digestibility or bioactive release at specific sites within the gastrointestinal tract.

Nhe5 deficiency enhances learning and memory via upregulating Bdnf/TrkB signaling in mice

Nhe5, a Na⁺ /H⁺ exchanger, is predominantly expressed in brain tissue and is proposed to act as a negative regulator of dendritic spine growth. Up to now, its physiological function in vivo remains unclear. Here we show that Nhe5-deficient mice exhibit markedly enhanced learning and memory in Morris water maze, novel object recognition, and passive avoidance task. Meanwhile, the pre- and post-synaptic components, synaptophysin (Syn) and post-synaptic density 95 (PSD95) expression levels were found increased in hippocampal regions lacking of Nhe5, suggesting a possible alterations in neuronal synaptic structure and function in Nhe5^-/- mice. Further study reveals that Nhe5 deficiency leads to higher Bdnf expression levels, followed by increased phosphorylated TrkB and PLCγ levels, indicating that Bdnf/TrkB signaling is activated due to Nhe5 deficiency. Moreover, the corresponding brain regions of Nhe5^-/- mice display elevated ERK/CaMKII/CREB phosphorylation levels. Taken together, these findings uncover a novel physiological function of Nhe5 in regulating learning and memory, further implying Nhe5 as a potential therapeutic target for improving cognition.

Lacking of palladin leads to multiple cellular events changes which contribute to NTD

Background

The actin cytoskeleton-associated protein palladin plays an important role in cell motility, morphogenesis and adhesion. In mice, Palladin deficient embryos are lethal before embryonic day (E) 15.5, and exhibit severe cranial neural tube and body wall closure defects. However, the mechanism how palladin regulates the process of cranial neural tube closure (NTC) remains unknown.

Methods

In this paper, we use gene knockout mouse to elucidate the function of palladin in the regulation of NTC process.

Results

We initially focuse on the expression pattern of palladin and found that in embryonic brain, palladin is predominantly expressed in the neural folds at E9.5. We further check the major cellular events in the neural epithelium that may contribute to NTC during the early embryogenesis. Palladin deficiency leads to a disturbance of cytoskeleton in the neural tube and the cultured neural progenitors. Furthermore, increased cell proliferation, decreased cell differentiation and diminished apical cell apoptosis of neural epithelium are found in palladin deficient embryos. Cell cycle of neural progenitors in Palladin^-/- embryos is much shorter than that in wt ones. Cell adhesion shows a reduction in Palladin^-/- neural tubes.

Conclusions

Palladin is expressed with proper spatio-temporal pattern in the neural folds. It plays a crucial role in regulating mouse cranial NTC by modulating cytoskeleton, proliferation, differentiation, apoptosis, and adhesion of neural epithelium. Our findings facilitate further study of the function of palladin and the underlying molecular mechanism involved in NTC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13064-017-0081-6) contains supplementary material, which is available to authorized users.