NSC3852 (5-nitroso-8-quinolinol) has cell differentiation and antiproliferative activity in human breast cancer cells in tissue culture and antitumor activity in mice bearing P388 and L1210 leukemic cells. We investigated the mechanism of NSC3852 action in MCF-7 human breast cancer cells using electron spin resonance (ESR). Reactive oxygen species (ROS) were detected in MCF-7 cell suspensions incubated with NSC3852 using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Formation of the DMPO-OH adduct was quenched by the addition of superoxide dismutase but not by catalase, and we concluded that superoxide was generated in the NSC3852-treated cells. The flavoprotein inhibitor diphenylene iodonium suppressed ROS production, providing evidence for the involvement of a flavin-dependent enzyme system in the ROS response to NSC3852. A biologically significant oxidative response to NSC3852 occurred in MCF-7 cells. An early marker of oxidative stress was a decrease in the [glutathione]/[glutathione disulfide] ratio 1 h after NSC3852 addition. Oxidative DNA damage, marked by the presence of 8-oxoguanine, and DNA-strand breakage occurred in cells exposed to NSC3852 for 24 h. Apoptosis peaked 48 h after exposure to NSC3852. Pretreatment with the glutathione precursor N-acetyl-L-cysteine (NAC) prevented DNA-strand breakage and apoptosis. Pretreatment with NAC also reversed NSC3852 decreases in E2F1, Myc, and phosphorylated retinoblastoma protein, indicative of redox-sensitive pathway(s) in MCF-7 cells during G 1 phase of the cell cycle. We conclude that ROS formation is involved in the apoptotic and cell differentiation responses to NSC3852 in MCF-7 cells.
The inhibition of glucose-6-phosphate dehydrogenase (G6PD) expression by arachidonic acid occurs by changes in the rate of pre-mRNA splicing. Here, we have identified a cis-acting RNA element required for regulated splicing of G6PD mRNA. Using transfection of G6PD RNA reporter constructs into rat hepatocytes, the cis-acting RNA element involved in this regulation was localized to nucleotides 43-72 of exon 12 in the G6PD mRNA. In in vitro splicing assays, RNA substrates containing exon 12 were not spliced. In contrast, RNA substrates containing other regions (exons 8 and 9 or exons 10 and 11) of the G6PD mRNA were efficiently spliced. Furthermore, exon 12 can inhibit splicing when substituted for other exons in RNA substrates that are readily spliced. This activity of the exon 12 regulatory element suggests that it is an exonic splicing silencer. Consistent with its activity as a splicing silencer, spliceosome assembly was inhibited on RNA substrates containing exon 12 compared with RNAs representing other regions of the G6PD transcript. Elimination of nucleotides 43-72 of exon 12 did not restore splicing of exon 12-containing RNA; thus, the 30-nucleotide element may not be exclusively a silencer. The binding of heterogeneous nuclear ribonucleoproteins K, L, and A2/B1 from both HeLa and hepatocyte nuclear extracts to the element further supports its activity as a silencer. In addition, SR proteins bind to the element, consistent with the presence of enhancer activity within this sequence. Thus, an exonic splicing silencer is involved in the inhibition of splicing of a constitutively spliced exon in the G6PD mRNA.Glucose-6-phosphate dehydrogenase (G6PD) 2 is a member of a family of enzymes that catalyze the de novo synthesis of fatty acids. In liver, the lipogenic pathway plays an essential role in converting excess dietary energy into a storage form. Consistent with this role in energy homeostasis, the capacity of this pathway is regulated by dietary changes, such as fasting, feeding, and the amount and type of carbohydrate and polyunsaturated fat in the diet (1). For many of the lipogenic enzymes, regulation of enzyme amount occurs primarily by changes in the transcription rate of the gene, but posttranscriptional regulation via mRNA stability has also been implicated (1). G6PD differs from the other family members in that dietary regulation occurs exclusively at a posttranscriptional step (2-4).G6PD expression is inhibited by polyunsaturated fatty acids, such as arachidonic acid; this occurs at a unique posttranscriptional step involving a decrease in the rate of splicing of the nascent G6PD transcript. Several lines of evidence indicate that changes in mature mRNA accumulation are caused by changes in the efficiency of splicing of the G6PD transcript. First, changes in the cytoplasmic accumulation of G6PD mRNA are preceded by changes in the accumulation of mRNA in the nucleus in the absence of changes in transcriptional activity of the gene (3-5). Second, stimulatory treatments, such as refeeding, enhance the ...
BackgroundAppalachia is characterized by poor health behaviors, poor health status, and health disparities. Recent interventions have not demonstrated much success in improving health status or reducing health disparities in the Appalachian region. Since one's perception of personal health precedes his or her health behaviors, the purpose of this project was to evaluate the self-rated health of Appalachian adults in relation to objective health status and current health behaviors.MethodsAppalachian adults (n = 1,576) were surveyed regarding health behaviors - soda consumer (drink ≥ 355 ml/d), or non-consumer (drink < 355 ml/d), fast food consumer (eating fast food ≥ 3 times/wk) or healthy food consumer (eating fast food < 3 times/wk), smoking (smoker or non-smoker), exercise (exerciser > 30 min > 1 d/wk) and sedentary (exercise < 30 min 1 d/wk), blood pressure medication (yes, no), and self-rated health. Blood pressure was measured through auscultation and serum cholesterol measured via needle prick. Weight status was based on BMI: normal weight (NW ≥ 18.5 and < 25.0), overweight (OW ≥ 25.0 and < 30.0), and obese (OB ≥ 30.0). Jaccard Binary Similarity coefficients, odds ratios, chi-square, and prevalence ratios were calculated to evaluate the relationships among self-rated health, objective health status, and health behaviors. Significance was set at p < 0.05.ResultsRespondents reported being healthy, while being sedentary (65%), hypertensive (76%), overweight (73%), or hyperlipidemic (79%). Between 57% and 66% of the respondents who considered themselves healthy had at least two disease conditions or poor health behaviors. Jaccard Binary Similarity coefficients and odds ratios showed the probability of reporting being healthy when having a disease condition or poor health behavior was high.ConclusionsThe association between self-rated health and poor health indicators in Appalachian adults is distorted. The public health challenge is to formulate messages and programs about health and health needs which take into account the current distortion about health in Appalachia and the cultural context in which this distortion was shaped.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.