Lysine-Specific Demethylase 1 in Breast Cancer Cells Contributes to the Production of Endogenous Formaldehyde in the Metastatic Bone Cancer Pain Model of Rats

Background

Bone cancer pain seriously affects the quality of life of cancer patients. Our previous study found that endogenous formaldehyde was produced by cancer cells metastasized into bone marrows and played an important role in bone cancer pain. However, the mechanism of production of this endogenous formaldehyde by metastatic cancer cells was unknown in bone cancer pain rats. Lysine-specific demethylase 1 (LSD1) is one of the major enzymes catalyzing the production of formaldehyde. The expression of LSD1 and the concentration of formaldehyde were up-regulated in many high-risk tumors.

Objective

This study aimed to investigate whether LSD1 in metastasized MRMT-1 breast cancer cells in bone marrows participated in the production of endogenous formaldehyde in bone cancer pain rats.

Methodology/Principal Findings

Concentration of the endogenous formaldehyde was measured by high performance liquid chromatography (HPLC). Endogenous formaldehyde dramatically increased in cultured MRMT-1 breast cancer cells in vitro, in bone marrows and sera of bone cancer pain rats, in tumor tissues and sera of MRMT-1 subcutaneous vaccination model rats in vivo. Formaldehyde at a concentration as low as the above measured (3 mM) induced pain behaviors in normal rats. The expression of LSD1 which mainly located in nuclei of cancer cells significantly increased in bone marrows of bone cancer pain rats from 14 d to 21 d after inoculation. Furthermore, inhibition of LSD1 decreased the production of formaldehyde in MRMT-1 cells in vitro. Intraperitoneal injection of LSD1 inhibitor pargyline from 3 d to 14 d after inoculation of MRMT-1 cancer cells reduced bone cancer pain behaviors.

Conclusion

Our data in the present study, combing our previous report, suggested that in the endogenous formaldehyde-induced pain in bone cancer pain rats, LSD1 in metastasized cancer cells contributed to the production of the endogenous formaldehyde.     

High-level production of poly (β-<Emphasis Type="SmallCaps">l</Emphasis>-malic acid) with a new isolated <Emphasis Type="Italic">Aureobasidium pullulans</Emphasis> strain

Poly (β-l-malic acid) (PMLA) is a water-soluble polyester with many attractive properties in chemical industry and medicine development. However, the low titer of PMLA in the available producer strains limits further industrialization efforts and restricts its many potential applications. In order to solve this problem, a new strain with the distinguished high productivity of PMLA was isolated from fresh plants samples. It was characterized as the candidate of Aureobasidium pullulans based on the morphology and phylogenetic analyses of the internal transcribed spacer sequences. After the optimization of culture conditions, the highest PMLA concentration (62.27 g l⁻¹) could be achieved in the shake flask scale. In addition, the contribution of the carbon flux to exopolysaccharide (EPS) and PMLA could be regulated by the addition of CaCO₃ in the medium. This high-level fermentation process was further scaled up in the 10 l benchtop fermentor with a high PMLA concentration (57.2 g l⁻¹) and productivity (0.35 g l⁻¹ h⁻¹), which are the highest level in all the literature. Finally, the suitable acid hydrolysis conditions of PMLA were also investigated with regard to the production of l-malic acid, and the kinetics of PMLA acid hydrolysis was modeled to simulate the whole degradation process. The present work paved the road to produce this multifunctional biomaterial (PMLA) at industrial scale and promised one alternative method to produce l-malic acid in the future.     

Cerebrospinal fluid Th1/Th2 cytokine profiles in children with enterovirus 71‐associated meningoencephalitis

Enterovirus 71 (EV71) infection can cause severe neurological complications including meningoencephalitis (ME) in some patients with hand, foot and mouth disease (HFMD). However, to date no studies have reported changes in cytokine concentrations and their correlations with clinical variables in patients with ME following EV71 infection. In this study, responses of Th1/Th2 cytokine, including IL‐2, IL‐4, IL‐6, IL‐10, TNF‐α and IFN‐γ, in cerebrospinal fluid (CSF) from patients with EV71‐related HFMD with ME and patients with febrile convulsions (FC) were analyzed using cytometric bead array technology. It was found that CSF IL‐6 and IFN‐γ concentrations were significantly higher in patients with EV71‐related ME than in those with FC. Additionally, both CSF IL‐6 and IFN‐γ concentrations were correlated with CSF cytology, fever duration and duration of hospital stay. More interestingly, a positive correlation between CSF IL‐6 and IFN‐γ concentrations was observed. Finally, receiver operating characteristic analysis revealed that when a cutoff value of 9.40 pg/mL was set for IL‐6, the sensitivity and specificity were 84.5% and 85.5%, respectively, for discriminating EV71‐related ME from FC. In conclusion, IL‐6 and IFN‐γ may be associated with EV71‐induced neuropathology.     

^137Cs,^134Cs在人工海洋小生境中的行为

在自行建立的人工海洋小生境中,采用示踪法综合地研究~(137)Cs、~(134)Cs在人工小生境中的行为。结果表明,~(137)Cs和~(134)Cs具有共同的生理生态行为,并表现出相似的规律、沉积物对~(137)Cs、~(134)Cs的吸附能力甚低,~(137)Cs、~(134)Cs在海洋动物体内趋于全身性的分布。各主要生化物质均能检出~(137)Cs、~(134)Cs。排泄实验后,海洋动物的胃肠、肝(消化腺)~(137)Cs、~(134)Cs损失显著。沉积物表现为解吸-重吸附的过程。     

Biotinylation of double stranded DNA after transamination

The bisulfite catalyzed transamination of cytidine and cytosine has been reported to be single strand specific, but local thermal instabilities of the DNA double helix, coupled with the extreme sensitivity of the Biotin-Avidin revelation methods, allows the random labelling of cytosines in d.s. DNA to detectable levels for those purposes where the overall label can be very low. We have evaluated the use of this reaction to prepare double stranded DNA molecules containing N4-aminoethyl-cytosine (4-aeC). After this step 4-aeC residues can be conjugated to biotinyl-n-hydroxysuccinimide ester yielding biotinylated DNA. This reaction allows the massive production of biotinylated probes. Labelled DNA can serve as molecular weight marker and positive control in Southern-blots. Moreover it can be useful in the study of DNA-protein interaction and in the isolation of d.s. DNA-binding proteins through chromatographic procedures.     

Improving aquaporin Z expression in <Emphasis Type="Italic">Escherichia coli</Emphasis> by fusion partners and subsequent condition optimization

Aquaporin Z (AqpZ), a typical orthodox aquaporin with six transmembrane domains, was expressed as a fusion protein with TrxA in E. coli in our previous work. In the present study, three fusion partners (DsbA, GST and MBP) were employed to improve the expression level of this channel protein in E. coli. The result showed that, compared with the expression level of TrxA-AqpZ, five- to 40-fold increase in the productivity of AqpZ with fusion proteins was achieved by employing these different fusion partners, and MBP was the most efficient fusion partner to increase the expression level. By using E. coli C43 (DE3)/pMAL-AqpZ, the effects of different expression conditions were investigated systematically to improve the expression level of MBP-AqpZ in E. coli. The high productivity of MBP-AqpZ (200 mg/l) was achieved under optimized conditions. The present work provides a novel approach to improve the expression level of membrane proteins in E. coli.     

Na+-K+--ATPase-mediated signal transduction: from protein interaction to cellular function

The Na+-K+--ATPase, or Na+ pump, is a member of the P-type ATPase superfamily. In addition to pumping ions, Na+-K+--ATPase is engaged in assembly of multiple protein complexes that transmit signals to different intracellular compartments. The signaling function of the enzyme appears to have been acquired through the evolutionary incorporation of many specific binding motifs that interact with proteins and ligands. In some cell types the signaling Na+ --ATPase and its protein partners are compartmentalized in coated pits (i.e., caveolae) the plasma membrane. Binding of ouabain to the signaling Na+-K+--ATPase activates the cytoplasmic tyrosine kinase Src, resulting in the formation of an active "binary receptor" that phosphorylates and assembles other proteins into different signaling modules. This in turn activates multiple protein kinase cascades including mitogen-activated protein kinases and protein kinase C isozymes in a cell-specific manner. It also increases mitochondrial production of reactive oxygen species (ROS)and regulates intracellular calcium concentration. Crosstalk among the activated pathways eventually results in changes in the expression of a number of genes. Although ouabain stimulates hypertrophic growth in cardiac myocytes and proliferation in smooth muscle cells, it also induces apoptosis in many malignant cells. Finally, the signaling function of the enzyme is also pivotal to ouabain-induced nongenomic effects on cardiac myocytes.