Melatonin enhances thapsigargin-induced apoptosis through reactive oxygen species-mediated upregulation of CCAAT-enhancer-binding protein homologous protein in human renal cancer cells

Melatonin (N-acetyl-5-methoxytryptamine) has differentiated the effects on apoptosis in normal and cancer cells. The mechanisms that account for the opposite effects on these cells are not adequately understood. In this study, we investigated the combined effect of melatonin and thapsigargin (TG) on apoptosis of renal cancer cells. Cotreatment with melatonin (1mm) and TG (50nm) induced approximately 10-fold expression levels of CCAAT-enhancer-binding proteins homologous protein (CHOP) compared with that of TG (50nm) alone. Downregulation of CHOP expression using small interfering RNAs markedly attenuated melatonin plus TG-mediated apoptosis. In addition, cotreatment with TG- and melatonin-induced CHOP upregulation likely relates to melatonin's antioxidant capacity because we proved that this CHOP upregulation is melatonin receptor independent. Our results collectively demonstrate that the upregulation of CHOP contributes to the enhancing effect of melatonin plus TG on apoptosis in cancer cells.     

胰岛素样生长因子结合蛋白3增强子元件(IEE)的生物学特征

背景:在细胞水平,胰岛素样生长因子结合蛋白3竞争性地与胰岛素样生长因子结合阻止了胰岛素样生长因子与其受体结合,从而抑制了胰岛素样生长因子的活性.目的:观察衰老细胞中调节性蛋白质胰岛素样生长因子结合蛋白3的生物学特征.设计、时间及地点:单一样本观察,于2006-09/2007-09在西安交通大学生物医学信息工程教育部重点实验室完成.材料:人胚肿二倍体成纤维细胞(2BS)购于中国生物制品研究所.方法:用Northern的方法显示胰岛素样生长因子结合蛋白3基因的表达在年轻和衰老的2BS细胞中存在差异:聚合酶链反应扩增出人类胰岛素样生长因子结合蛋白3上游包括5'-UTR区的2kb的序列,并用酶切得到4组不同长短的胰岛素样生长因子结合蛋白3启动子片段并确定可调控转录活性的区域;通过重叠寡核苷酸凝胶阻滞实验确定在该活性区域中的增强子元件-IEE(IGFBP-3 enhancerelement)及其与蛋白结合的碱基序列等;用DNase I Footprinting法确定了IEE中与蛋白结合的核心序列.主要观察指标:①胰岛素样生长因子结合蛋白3基因在年轻和衰老细胞中的表达差异.②通过重叠寡核苷酸确定增强子元件.③通过凝胶阻滞试验证实该复合物结合活性与衰老相关的.④通过凝胶阻滞试验确定IEE与蛋白结合的碱基序列.⑤用DNase I Footprinting法确定IEE中与蛋白结合的核心序列.⑥判断与IEE结合蛋白的相对分子质量.结果:与年轻的2BS细胞相比,衰老的2BS细胞中胰岛素样生长因子结合蛋白3基因的表达升高:5'-ccagcctgccaa gca gcg tgcCCCggttgc-3'是胰岛素样生长因子结合蛋白3的增强子元件;该元件与蛋白结合的核心序列是CTG CCA和GCGTGC CCC G,而且这种结合是与衰老相关的:结合蛋白的相对分子质量大约在27 000.结论:在2BS细胞中发现了一个新的转录增强子,它与蛋白结合的核心序列是CTGCCA和GCG TGC CCC G,可与一个大约27 000的蛋白结合:在衰老细胞中可选择性地促进胰岛素样生长因子结合蛋白3的表达.     

Modafinil Prevents Inhibitory Avoidance Memory Deficit Induced by Sleep Deprivation in Rats

Study Objectives:

Evaluation of modafinil effects on the inhibitory avoidance task (IA).

Design:

Rats were trained on a multiple trial IA task after receiving modafinil or vehicle injections. In experiment 1 they were trained with a weak protocol under baseline condition and in experiment 2, with a stronger protocol under sleep-deprivation condition.

Results:

In experiment 1 modafinil improved rats'' acquisition whereas the retention test remained unaffected. In Experiment 2 modafinil did not interfere with training performance, but the lower dose prevented the retention impairment in sleep-deprived animals.

Conclusions:

Modafinil is able to improve acquisition in normal rats and reverse the long-term memory impairment induced by sleep-deprivation.

Citation:

Moreira KM; Ferreira TL; Hipolide DC; Fornari RV; Tufik S; Oliveira MGM. Modafinil prevents inhibitory avoidance memory deficit induced by sleep deprivation in rats. SLEEP 2010;33(7):990-993.     

Cell cycle dependent intracellular distribution of two spliced isoforms of TCP/ILF3 proteins

TCP80 is an approximately 80kDa mammalian cytoplasmic protein that binds to a set of mRNAs and inhibits their translation in vitro and ex vivo. This protein has high sequence similarity to interleukin-2 enhancer-binding factors (NF90/ILF3) and the M-phase phosphoprotein (MPP4)/DRBP76. A 110kDa immunologic isoform of TCP80/NF90/MPP4/DRBP76, termed TCP110, also is present in cytoplasm and nuclei of many types of cells. A cDNA sequence coding for TCP110 was derived by 5(')RACE. The TCP110 sequence is identical to ILF3. The gene coding for TCP110/ILF3 mapped to human chromosome 19 and the gene organization was analyzed using TCP80 and TCP110/ILF3 cDNA sequences. The TCP/ILF3 gene spans >34.8kb and contains 21 exons. At least one alternatively spliced product involving exons 19-21 exists and predicts the formation of either TCP80 or TCP110/ILF3. However, the functional relationships of TCP80 and TCP110/ILF3 required elucidation. The metabolic turnover rates and subcellular distribution of TCP80 and TCP110/ILF3 during the cell cycle showed TCP80 to be relatively stable (t(1/2)=5 days) in the cytoplasmic compartment. In comparison, TCP110/ILF3 migrated between the cytoplasmic and nuclear compartments during the cell cycle. The TCP110 C-terminal segment contains an additional nuclear localizing signal that plays a role in its nuclear translocation. This study indicates that the multiple cellular functions, i.e., translation control, interleukin-2 enhancer binding, or cell division, of TCP/ILF3 are fulfilled by alternatively spliced isoforms.     

Multiscale Modeling Framework of Transdermal Drug Delivery

This study addresses the modeling of transdermal diffusion of drugs to better understand the permeation of molecules through the skin, especially the stratum corneum, which forms the main permeation barrier to percutaneous permeation. In order to ensure reproducibility and predictability of drug permeation through the skin and into the body, a quantitative understanding of the permeation barrier properties of the stratum corneum (SC) is crucial. We propose a multiscale framework of modeling the multicomponent transdermal diffusion of molecules. The problem is divided into subproblems of increasing length scale: microscopic, mesoscopic, and macroscopic. First, the microscopic diffusion coefficient in the lipid bilayers of the SC is found through molecular dynamics (MD) simulations. Then, a homogenization procedure is performed over a model unit cell of the heterogeneous SC, resulting in effective diffusion parameters. These effective parameters are the macroscopic diffusion coefficients for the homogeneous medium that is “equivalent” to the heterogeneous SC, and thus can be used in finite element simulations of the macroscopic diffusion process. The resulting drug flux through the skin shows very reasonable agreement to experimental data. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.