Omega-3 fatty acids plus vitamin for women with gestational diabetes or prediabetes: a meta-analysis of randomized controlled studies.

INTRODUCTION: Omega-3 fatty acids plus vitamin (e.g. vitamin D and E) may be beneficial to treat gestational diabetes mellitus (GDM), and we aimed to study the influence of omega-3 fatty acids plus vitamin versus placebo on the treatment efficacy of GDM. METHODS: We searched the databases including PubMed, Embase, and the Cochrane Central Register of Controlled Trials, and randomized controlled trials (RCTs) assessing the influence of omega-3 fatty acids and vitamins combination supplementation versus placebo on metabolic status of GDM were included. RESULTS: Five RCTs were included in the meta-analysis. Compared with control intervention for women with GDM or prediabetes, omega-3 fatty acids plus vitamin substantially reduced fasting plasma glucose (FPG, mean difference [MD] = -11.25; 95% confidence intervals [CI] = -13.73 to -8.77; p < .00001), insulin (MD=-6.16; 95% CI=-7.92 to -4.39; p < .00001), homeostasis model of assessment-insulin resistance (HOMA-IR, MD = 173.51; 95% CI = 164.72 to 182.30; p < .00001) and triglycerides (MD = 173.51; 95% CI = 164.72 to 182.30; p < .00001), as well as increased total antioxidant capacity (TAC, MD = 173.51; 95% CI = 164.72 to 182.30; p < .00001), but revealed no significant impact on total cholesterol (MD = 173.51; 95% CI = 164.72 to 182.30; p < .00001), low­density lipoprotein cholesterol (LDL-C, MD = 173.51; 95% CI = 164.72 to 182.30; p < .00001), preterm delivery (OR = 173.51; 95% CI = 164.72 to 182.30; p < .00001) or macrosomia > 4000 g (OR = 173.51; 95% CI = 164.72 to 182.30; p < .00001). CONCLUSIONS: The supplementation of omega-3 fatty acids in combination with vitamin D or E can improve glycemic control, alleviate oxidative stress, and reduce triglycerides, but had no effects on total cholesterol, preterm delivery or macrosomia > 4000 g in women with GDM or prediabetes.

Cell cycle-dependent regulation of a human DNA helicase that localizes in DNA damage foci.

Mutational studies of human DNA helicase B (HDHB) have suggested that its activity is critical for the G1/S transition of the cell cycle, but the nature of its role remains unknown. In this study, we show that during G1, ectopically expressed HDHB localizes in nuclear foci induced by DNA damaging agents and that this focal pattern requires active HDHB. During S and G2/M, HDHB localizes primarily in the cytoplasm. A carboxy-terminal domain from HDHB confers cell cycle-dependent localization, but not the focal pattern, to a reporter protein. A cluster of potential cyclin-dependent kinase phosphorylation sites in this domain was modified at the G1/S transition and maintained through G2/M of the cell cycle in vivo, coincident with nuclear export of HDHB. Serine 967 of HDHB was the major site phosphorylated in vivo and in vitro by cyclin-dependent kinases. Mutational analysis demonstrated that phosphorylation of serine 967 is crucial in regulating the subcellular localization of ectopically expressed HDHB. We propose that the helicase of HDHB operates primarily during G1 to process endogenous DNA damage before the G1/S transition, and it is largely sequestered in the cytoplasm during S/G2.

p53 protein activates the transcription of human proliferating cell nuclear antigen in response to 4-nitroquinoline N-oxide treatment.

4-nitroquinoline N-oxide (4-NQO) is a potent mutagen and carcinogen. To elucidate the cellular response to 4-NQO, we studied the transcriptional regulation of human proliferating cell nuclear antigen (hPCNA), an essential protein in DNA replication and repair, after 4-NQO treatment. We found that hPCNA promoter was dose-dependently transactivated by 4-NQO under the concentration of 2 microM via a previously reported p53-binding element located from -236 to -217 upstream of the transcription start site. Based on our western blot analysis, the phosphorylation of serine at the 15th residue (Ser15) of p53 was activated by 4-NQO, whereas the level of p53 in the cells did not change much. It was observed that Staurosporine, a Ser/Thr kinase inhibitor, blocked the Ser15 phosphorylation of p53 and the hPCNA promoter response to 4-NQO simultaneously, suggesting that Ser15 phosphorylated p53 was the 4-NQO-responsive hPCNA regulator. The [3H]-thymidine deoxyribose (TdR) incorporation assay and the comet assay showed that DNA repair was triggered when DNA replication was inhibited after the treatment of 4-NQO, and the hPCNA transactivation seemed to contribute to DNA repair. Taken together, our data indicate that after 4-NQO treatment hPCNA is transactivated by Ser15 phosphorylated p53, and participate in DNA repair.

Human DNA helicase B functions in cellular homologous recombination and stimulates Rad51-mediated 5'-3' heteroduplex extension in vitro.

Homologous recombination is involved in the repair of DNA damage and collapsed replication fork, and is critical for the maintenance of genomic stability. Its process involves a network of proteins with different enzymatic activities. Human DNA helicase B (HDHB) is a robust 5'-3' DNA helicase which accumulates on chromatin in cells exposed to DNA damage. HDHB facilitates cellular recovery from replication stress, but its role in DNA damage response remains unclear. Here we report that HDHB silencing results in reduced sister chromatid exchange, impaired homologous recombination repair, and delayed RPA late-stage foci formation induced by ionizing radiation. Ectopically expressed HDHB colocalizes with Rad51, Rad52, RPA, and ssDNA. In vitro, HDHB stimulates Rad51-mediated heteroduplex extension in 5'-3' direction. A helicase-defective mutant HDHB failed to promote this reaction. Our studies implicate HDHB promotes homologous recombination in vivo and stimulates 5'-3' heteroduplex extension during Rad51-mediated strand exchange in vitro.

HBV C promoter Sp1 binding sequence functionally substitutes for the yeast ARS1 ABF1 binding site.

Transcriptional factors have been implicated in eukaryotic DNA replication. We have studied the potential function of a viral promoter sequence in DNA replication. The hepatitis B virus (HBV) pregenomic promoter is regulated by two enhancers and cis-elements. The G-C rich region between 1734-1754 nt, which contains two SP1 binding sites, is necessary for transcription origin and HBV replication. We found that the Abf1-binding B3 element in yeast ARS1 can be functionally replaced by the viral Sp1-binding DNA sequence, which activates transcription from the HBV C promoter. Further, yeast RAP1 bound to the viral Sp1 binding sites in vitro. These results suggest that RAP1 binds to the Sp1 binding sites and stimulates yeast DNA replication.

Active cis-elements of PCNA Promoter in HeLa, HepG2, L-02 and MCF-7 Cell Lines.

Proliferating cell nuclear antigen (PCNA) is an auxiliary factor of DNA polymerase delta and epsilon and functions in DNA replication and repair. Using PCR methods, 17 sites within the human PCNA promoter from 60 to 538 were subjected to a 8 bp substitution mutagenesis. Wild type promoter and each mutated promoters were inserted into luciferase expression vector pGL2-Basic. These nonmutated and mutated PCNA promoters were assayed by transient transfection of the plasmids into HeLa, HepG2, L-02 and MCF-7 cell line, respectively. It was found that several sites were common cis acting elements and several sites were cell-specific cis acting elements. Data were further presented using in vitro transcription assay with HeLa and HepG2 nuclear extract.

Differential proteomic analysis of a highly metastatic variant of human breast cancer cells using two-dimensional differential gel electrophoresis.

Distant metastasis represents the major lethal cause of breast cancer. To understand the molecular mechanisms of breast cancer metastasis and identify markers with metastatic potential, we established a highly metastatic variant of parental MDA-MB-231 cells (MDA-MB-231HM). Using two-dimensional electrophoresis (2-DE), we performed a proteomic comparison of the two kinds of cells. As much as 51 protein spots were differentially expressed between the selected variant and its parental counterpart in at least 3 experiments. Ten unique proteins were identified using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS), liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), and database searching software. Among them, nine proteins were up-regulated in MDA-MB-231HM cells, including Macrophage-capping protein (CapG), Galectin-1, Chloride intracellular channel protein 1, Endoplasmic reticulum protein ERp29 precursor, Stathmin-1 (STMN1), Isoform 1 of uridine-cytidine kinase 2(UCK2), Rho GDP-dissociation inhibitor 2 (ARHGDIB), isocitrate dehydrogenase [NADP] cytoplasmic (IDH1), and N-myc downstream regulated gene 1 (NDRG1) protein. Only transgelin-2 was down-regulated. Differential expression was confirmed for three proteins including CapG, STMN1, and transgelin-2 by Western blotting analysis. Transgelin-2 was chosen for further verification by immunohistochemistry. The results suggested that 2-DE would be an efficient way to screen the proteins responsible for specific biological function. Furthermore, the findings imply that different proteins may be involved in the metastatic process in breast carcinomas.

[Activating effect of hepatitis B virus preS/S protein on proliferating cell nuclear antigen gene promoter].

BACKGROUND: PreS/S gene was derived from hepatitis B virus (HBV) integration fragment of human hepatocellular carcinoma genome, containing the promoter of preS/S and the C terminal truncated preS/S open reading frame. PreS/S protein may have important roles in processing hepatoma in some HBV-infected patients. The aim of the study was to study the activity of HBV preS/S protein on proliferating cell nuclear antigen (PCNA) promoter and to localize compartment of the preS/S protein in the liver cell line L02. METHODS: The authors studied the effect of the 3 -truncated preS/S on human PCNA promoter by co-transfecting the expression plasmids of luciferase reporter gene, used the immunohistochemical method to localize the preS/S protein. RESULTS: The expression product of the plasmid, pKSH7C-HpaI which contained the 3 -truncated preS/S and the flanking cellular sequences, stimulated the expression of PCNA promoter dose dependently,and its effect was 0.5 folds higher than control. Immunohistochemistry showed that the preS/S protein located in the cytosolic region of the liver cell line L02. CONCLUSIONS: The HBV preS/S protein could stimulate the PCNA promoter of the liver cell, its effect was not direct, which suggests that the effect of preS/S protein on PCNA promoter was probably through the cell signal transduction pathway.