Retinoblastoma treatment: impact of the glycolytic inhibitor 2-deoxy-d-glucose on molecular genomics expression in LHBETATAG retinal tumors

Purpose: The purpose of this study was to evaluate the effect of 2-deoxy-D-glucose (2-DG) on the spatial distribution of the genetic expression of key elements involved in angiogenesis, hypoxia, cellular metabolism, and apoptosis in LHBETATAG retinal tumors. Methods: The right eye of each LHBETATAG transgenic mouse (n = 24) was treated with either two or six subconjunctival injections of 2-DG (500 mg/kg) or saline control at 16 weeks of age. A gene expression array analysis was performed on five different intratumoral regions (apex, center, base, anterior-lateral, and posterior-lateral) using Affymetrix GeneChip Mouse Gene 1.0 ST arrays. To test for treatment effects of each probe within each region, a two-way analysis of variance was used. Results: Significant differences between treatment groups (ie, 0, 2, and 6 injections) were found as well as differences among the five retinal tumor regions evaluated (P \u3c 0.01). More than 100 genes were observed to be dysregulated by ≥2-fold difference in expression between the three treatment groups, and their dysregulation varied across the five regions assayed. Several genes involved in pathways important for tumor cell growth (ie, angiogenesis, hypoxia, cellular metabolism, and apoptosis) were identified. Conclusions: 2-DG was found to significantly alter the gene expression in LHBETATAG retinal tumor cells according to their location within the tumor as well as the treatment schedule. 2-DG’s effects on genetic expression found here correlate with previous reported results on varied processes involved in its in vitro and in vivo activity in inhibiting tumor cell growth

Antiangiogenic Activity of 2-Deoxy-D-Glucose

During tumor angiogenesis, endothelial cells (ECs) are engaged in a number of energy consuming biological processes, such as proliferation, migration, and capillary formation. Since glucose uptake and metabolism are increased to meet this energy need, the effects of the glycolytic inhibitor 2-deoxy-D-glucose (2-DG) on in vitro and in vivo angiogenesis were investigated.In cell culture, 2-DG inhibited EC growth, induced cytotoxicity, blocked migration, and inhibited actively forming but not established endothelial capillaries. Surprisingly, 2-DG was a better inhibitor of these EC properties than two more efficacious glycolytic inhibitors, 2-fluorodeoxy-D-glucose and oxamate. As an alternative to a glycolytic inhibitory mechanism, we considered 2-DG's ability to interfere with endothelial N-linked glycosylation. 2-DG's effects were reversed by mannose, an N-linked glycosylation precursor, and at relevant concentrations 2-DG also inhibited synthesis of the lipid linked oligosaccharide (LLO) N-glycosylation donor in a mannose-reversible manner. Inhibition of LLO synthesis activated the unfolded protein response (UPR), which resulted in induction of GADD153/CHOP and EC apoptosis (TUNEL assay). Thus, 2-DG's effects on ECs appeared primarily due to inhibition of LLOs synthesis, not glycolysis. 2-DG was then evaluated in two mouse models, inhibiting angiogenesis in both the matrigel plug assay and the LH(BETA)T(AG) transgenic retinoblastoma model.In conclusion, 2-DG inhibits endothelial cell angiogenesis in vitro and in vivo, at concentrations below those affecting tumor cells directly, most likely by interfering with N-linked glycosylation rather than glycolysis. Our data underscore the importance of glucose metabolism on neovascularization, and demonstrate a novel approach for anti-angiogenic strategies

Ultraviolet Light-Induced Unscheduled Dna Synthesis In Isolated Myocardial Cells From Different Aged Rats

Technik von gestern für die Ziele von morgen? : energiepolit. Orientierungen auf d. Weg zur postmaterialist. Ges. / Walter Molt ... (Hrsg.). - Opladen : Westdt. Verl., 1986. - 153 S

From delocalized lipophilic cations to hypoxia: blocking tumor cell mitochondrial function leads to therapeutic gain with glycolytic inhibitors

An unexpected similarity between cancer and cardiac muscle cells in their sensitivity to anthracyclines and delocalized lipophilic cations (DLC) prompted a series of studies in which it was shown that the positive charge of these compounds is central to their selective accumulation and toxicity in these two distinct cell types. An initial finding to explain this phenomenon was that cancer and cardiac muscle cells exhibit high negative plasma membrane potentials resulting in increased uptake of these agents. However, the p-glycoprotein efflux pump was shown to be another factor underlying differential accumulation of these compounds, since it recognizes positively charged drugs and thereby actively reduces their intracellular concentrations. The delocalized positive charge and lipophilicity of DLCs leads to their retention and inhibition of ATP synthesis in mitochondria. Years later it was realized that cancer cells in the hypoxic portions of solid tumors were similar to those treated with DLCs in relying mainly on anaerobic metabolism for survival and could thus be targeted with a glycolytic inhibitor, 2-deoxy-D-glucose (2-DG). This hypothesis has lead to a Phase I clinical trial in which 2-DG is used to selectively kill the hypoxic tumor cell population which are resistant to standard chemotherapy or radiation

Interferon Inhibits Cardiac Cell Function in Vitro

Abstract Interferon which has been shown to exert important effects on cellular function was utilized to investigate its effect on cardiac cell beating in vitro. When steadily pulsating rat cardiac cultures were continuously exposed to rat interferon for 24 hr, a decrease in the beating rate was observed. Mouse interferon which also exerted antiviral activity on rat heart nonmuscle cells also decreased the beating rate of rat cardiac cultures. Human leukocyte interferon when tested at the same dose at which rat interferon was active, exhibited no antiviral activity in rat heart nonmuscle cells and did not exert beating rate effects. When mouse interferon was incubated with antiserum prepared against mouse interferon both antiviral and beating activity were neutralized to the same extent. None of the interferons used produced morphological effects on the heart cells and with rat interferon the beating rate effect was reversible. This finding, that interferon affects cardiac cell function in vitro, may have relevance to clinical application

8 - Effects of Creatine Phosphate on Cultured Cardiac Cells

This chapter discusses the effects of creatine phosphate on cultured cardiac cells. Cardiac muscle cells are unique in that they maintain their ability to beat in culture for prolonged periods. The beating of the cells is both characteristic of and dependent upon their environment, which can be rigorously controlled by the culture medium. Thus, if the medium is made hypoxic, the cells stop beating. The response to such an intervention is used as a model of the whole organ under similar conditions. It reports that cardiac cells growing in culture are not irreversibly damaged by prolonged exposure to 100% CO2. The addition of exogenous creatine phosphate (PCr) does not alter the arrhythmic effect produced by 100% CO2 treatment or the arrest or recovery times. Since intracellular PCr is known to be lowered in adriamycin (ADM) treated hearts, as well as other pathological muscle tissues, it is possible that the addition of this compound exogenously restores some minimal level necessary for beating. The chapter also focuses on whether PCr may have clinical application in patients treated with ADM

Abstract 4064: Overcoming resistance to 2-deoxy-glucose and glucose deprivation in tumor cells under normoxia by modulating the unfolded protein response

Abstract Background: Cancer cells have greater aerobic glycolysis than normal cells and therefore take up more glucose, as demonstrated by the positron emission tomography (PET) scan. This phenomenon can be exploited for cancer therapy using glycolytic inhibitors such as 2-deoxy-glucose (2-DG). Due to its structural similarity to mannose, 2-DG also interferes with N-linked glycosylation, a co-translational modification that directs protein folding. This obstruction triggers an unfolded protein response (UPR), which kills certain tumor types grown under normoxia, for example pancreatic cancer cell line, 1420 (ATCC Mia Paca-2). Since 2-DG is in clinical trials, we are investigating mechanisms by which tumor cells have acquired or are intrinsically resistant to 2-DG. By continuous 2-DG treatment of 1420 cells, we isolated a two-fold resistant variant cell line, 14DG2, and compared it to pancreatic cell line, 1469 (ATCC Panc-1), that intrinsically displays resistance to 2-DG. 2-DG has often been compared to and used as a substitute for glucose deprivation which can also lead to UPR. Glucose deprivation is common in tumor development since cells can outgrow the nutrient supply and may lack functional vasculature. Thus, we investigated the effects of glucose starvation on the same cell lines and compared our results to those where 2-DG induced UPR. Results: 2-DG resistant cell lines, 1469 and 14DG2, display greater sensitivity to glucose deprivation than 2-DG sensitive cell line 1420 which indicates that 2-DG treatment is not an adequate substitute for glucose deprivation. The resistant cell lines show lower protein levels of glucose transporters and/or hexokinase II, which correlates with their decreased uptake of radioactively-labeled 2-DG. We can deduce that these cells also take up less glucose and this may be the reason for their increased sensitivity to glucose starvation conditions. 2-DG resistant cell lines display higher basal levels of UPR folding chaperone Grp78 when measured by western blot. Using siRNA or versipelostatin to inhibit Grp78, a dramatic increase in 2-DG cytotoxicity in the two resistant cell lines was observed suggesting that the resistant cell lines are prepared to cope with ER stress more so than the sensitive cell line. Interestingly, these cell lines also showed resistance to tunicamycin but not to other ER stressors i.e. thapsigargin, brefeldin and velcade. Thus, it appears that 2-DG resistance in these cell lines is involved with processing of oligosaccharide and/or glycosylation interference. Conclusions: The manner in which glucose is restricted in tumor cells, i.e. 2-DG treatment or glucose deprivation, dictates resistance to these two different conditions. Resistance to 2-DG, which may arise in the clinical use of this sugar analog, can be overcome by reducing the effectiveness of the unfolded protein response. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4064. doi:10.1158/1538-7445.AM2011-4064</jats:p