Protective effects of acetyl-L-carnitine on cisplatin cytotoxicity and oxidative stress in neuroblastoma

Dysfunction of the carnitine cycle in tumor progression

The carnitine cycle is responsible for the transport of cytoplasmic fatty acids to the mitochondria for subsequent β-oxidation to maintain intracellular energy homeostasis. Recent studies have identified abnormalities in the carnitine cycle in various types of tumors; these abnormalities include the altered expression levels of carnitine cycle-related metabolic enzymes and transport proteins. Dysfunction of the carnitine cycle has been shown to influence tumorigenesis and progression by altering intracellular oxidative and inflammatory status or regulating tumor metabolic flexibility. Many therapeutic strategies targeting the carnitine cycle are actively being explored to modify the dysfunction of the carnitine cycle in patients with malignant tumors; such approaches include carnitine cycle-related enzyme inhibitors and exogenous carnitine supplementation. Therefore, here, we review the studies of carnitine in tumors, aiming to scientifically illustrate the dysfunction of the carnitine cycle in tumor progression and provide new ideas for further research.

SERPINB3-MYC axis induces the basal-like/squamous subtype and enhances disease progression in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) exhibits distinct molecular subtypes: classical/progenitor and basal-like/squamous. Our study aimed to identify genes contributing to the development of the basal-like/squamous subtype, known for its aggressiveness. Transcriptome analyses revealed consistent upregulation of SERPINB3 in basal-like/squamous PDAC, correlating with reduced patient survival. SERPINB3 transgene expression in PDAC cells enhanced in vitro invasion and promoted lung metastasis in a mouse PDAC xenograft model. Metabolome analyses unveiled a metabolic signature linked to both SERPINB3 and the basal-like/squamous subtype, characterized by heightened carnitine/acylcarnitine and amino acid metabolism, associated with poor prognosis in patients with PDAC and elevated cellular invasiveness. Further analysis uncovered that SERPINB3 inhibited the cysteine protease calpain, a key enzyme in the MYC degradation pathway, and drove basal-like/squamous subtype and associated metabolic reprogramming through MYC activation. Our findings indicate that the SERPINB3-MYC axis induces the basal-like/squamous subtype, proposing SERPINB3 as a potential diagnostic and therapeutic target for this variant.

The effects of cisplatin and jaceosidin on SH-SY5Y neuroblastoma cells: an electron microscopic, molecular and biochemical study

In this study, our aim was to show both the single and combined effects of cisplatin and jaceosidin in SHSY-5Y neuroblastoma cells. For this purpose, we used MTT cellular viability assay, Enzyme-Linked Immunosorbent Assay (ELISA), Transmission Electron Microscopy (TEM), Immunofluorescence Staining Assay (IFA) and Western blotting (WB) assay. According to MTT findings, IC50 dose was detected as 50 µM cisplatin and 160 µM jaceosidin co-application. Therefore, experimental groups were finally selected as control, cisplatin, 160 µM jaceosidin and Cisplatin +160 µM jaceosidin. Cell viability was decreased in all groups, and the IFA findings confirmed the viability analysis. WB data indicated that matrix metalloproteinase 2 and 9 levels, as indicators of metastasis, decreased. While LPO and CAT levels increased in all treatment groups, it was observed that the activity of SOD decreased. When TEM micrographs were investigated, cellular damages were determined. In the light of these results, it can be said that cisplatin and jaceosidin have a potential to increase the effects of each other synergistically.

Comparison of Cisplatin with Lipoplatin in Terms of Ototoxicity

OBJECTIVE

Cisplatin (CDDP) is an anti-neoplastic agent that has been used in treatments of both pediatric and adult cancers. It has many side effects, such as ototoxicity, nephrotoxicity, and neurotoxicity. Lipoplatin (LIPO) is a nanomolecule with 110 nm diameter and composed of lipids and CDDP. In this study, we aimed to compare the toxic effects of LIPO with CDDP in the cochlear cells with anti-tumoral doses determined in neuroblastoma cells.

MATERIALS AND METHODS

House Ear Institute Organ Corti 1 (HEI-OC1), MYC-N amplified KELLY, and MYC-N non-amplified SH-SY5Y human neuroblastoma cells were used in this study. Firstly, anti-tumoral lethal dose 50 (LD50) of LIPO and CDDP were determined using the WST-1 assay in both neuroblastoma cells. Then anti-tumoral doses of CDDP and LIPO were applied on HEI-OC1 cells for evaluating the toxic effects. The apoptotic cell death was measured using flow cytometric analysis of annexin-V/7-amino-actinomycin (7-AAD) and cell cycle tests.

RESULTS

LIPO or CDDP inhibited cell viability in a dose- and time-dependent manner in both neuroblastoma and HEI-OC1 cells. LD50 values were selected as 20 mM for CDDP and 750 mM for LIPO in neuroblastoma cells. After the 48-hour incubation, KELLY cells treated with 20 mM CDDP and 750 mM LIPO had a 53% viability; SH-SY5Y cells treated 20 mM CDDP and 750 mM LIPO had a 45% and 58% viability, respectively; and HEI-OC1 cells treated with 20 mM CDDP and 750 mM LIPO had a 65% and 82% viability, respectively.

CONCLUSION

LIPO showed less toxic effects in the HEI-OC1 cells compared to CDDP at anti-tumoral doses.

Role of N-acetyl cysteine and acetyl-l-carnitine combination treatment on DNA-damage-related genes induced by radiation in HEI-OC1 cells

PURPOSE

The aim of the present study was to evaluate the effect of acetyl-l-carnitine (ALC) and N-acetyl cysteine (NAC) on ionizing radiation (IR)-induced cytotoxicity and change in DNA damage-related genes in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells.

METHODS

HEI-OC1 cells were irradiated with 5 Gy radiation and treated by eight combinations of NAC and/or ALC: control, NAC, ALC, IR, NAC + IR, ALC + NAC, ALC + IR, and ALC + NAC + IR. Cell viability, apoptotic cell death, and DNA damage were measured at the 72nd hour. Eighty-four IR-induced DNA-damage-related genes were determined by RT-PCR gene array and >10-fold changes were considered significant.

RESULTS

IR decreased cell viability by about 50% at 72 hours of incubation. In particular, the ALC and/or NAC combination before IR protected the HEI-OC1 cells (p < .05). Single and combination treatment prior to IR led to lower apoptotic cell death (p < .05). There was a significant lower DNA damage in ALC + NAC + IR group compared to IR group (p < .05). Expressions of Brca2, Xpc, Mlh3, Rad51, Xrcc2, Hus1, Rad9a, Cdkn1a, Gadd45a which are the DNA-repair genes were found to be significantly higher in NAC + ALC + IR group than those in individual treatment of ALC or NAC.

CONCLUSIONS

ALC and/or NAC treatment prior to IR led to higher cell viability and lower apoptotic cell damage compared to the IR group. The results of the study show that the ALC + NAC combination treatment inhibits DNA damage and induces DNA-repair genes to repair radiation damage, and this combination treatment is more effective against radiation-induced DNA damage than NAC or ALC therapy individually.

In vitro and in vivo evaluation of etoposide - silk wafers for neuroblastoma treatment

High-risk neuroblastoma requires surgical resection and multi-drug chemotherapy. This study aimed to develop an extended release, implantable and degradable delivery system for etoposide, commonly used for neuroblastoma treatment. Different concentrations of silk, a biodegradable, non-toxic, non-immunogenic material were employed to prepare etoposide-loaded wafer formulations. Secondary structure of silk in the formulations was characterized using Fourier Transform Infrared (FTIR) spectroscopy and optimized based on the crystalline structure. Accelerated in vitro degradation studies under different conditions such as acidic, alkaline, oxidizing mediums and high temperature, were performed. The integrity of the silk wafer structure was maintained unless exposed to 0.1 N NaOH for 24 h. In vitro release of etoposide was performed in PBS (phosphate buffered saline) at 37 °C. Silk coated 6% wafers released the drug up to 45 days, while uncoated wafers released the drug for 30 days. Cytotoxicity study was performed on KELLY cells to evaluate the etoposide cytotoxicity (LC50) and the long-term efficacy of the etoposide wafer formulations. The results showed that etoposide killed 50% of the cells at 1 μg/mL concentration and the wafer formulations demonstrated significant cytotoxicity up to 22 days when compared to untreated cells. Using an orthotopic neuroblastoma mouse model, intra-tumoral implantation of the coated 6%, uncoated 6%, or uncoated 3% silk wafers were all effective at decreasing tumor growth. Histological examination revealed tumor cell necrosis adjacent to the drug-loaded silk wafer.

Liu Jun Zi Tang-A Potential, Multi-Herbal Complementary Therapy for Chemotherapy-Induced Neurotoxicity

Liu Jun Zi Tang (LJZT) has been used to treat functional dyspepsia and depression, suggesting its effects on gastrointestinal and neurological functions. LJZT is currently used as a complementary therapy to attenuate cisplatin-induced side effects, such as dyspepsia. However, its effect on chemotherapy-induced neuropathic pain or neurotoxicity has rarely been studied. Thus, we explored potential mechanisms underlying LJZT protection against cisplatin-induced neurotoxicity. We observed that LJZT attenuated cisplatin-induced thermal hyperalgesia in mice and apoptosis in human neuroblastoma SH-SY5Y cells. Furthermore, it also attenuated cisplatin-induced cytosolic and mitochondrial free radical formation, reversed the cisplatin-induced decrease in mitochondrial membrane potential, and increased the release of mitochondrial pro-apoptotic factors. LJZT not only activated the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1&alpha;) promoter region, but also attenuated the cisplatin-induced reduction of PGC-1&alpha; expression. Silencing of the PGC-1&alpha; gene counteracted the protection of LJZT. Taken together, LJZT mediated, through anti-oxidative effect and mitochondrial function regulation, to prevent cisplatin-induced neurotoxicity.

CDK2 inhibitors as candidate therapeutics for cisplatin- and noise-induced hearing loss

Hearing loss caused by aging, noise, cisplatin toxicity, or other insults affects 360 million people worldwide, but there are no Food and Drug Administration-approved drugs to prevent or treat it. We screened 4,385 small molecules in a cochlear cell line and identified 10 compounds that protected against cisplatin toxicity in mouse cochlear explants. Among them, kenpaullone, an inhibitor of multiple kinases, including cyclin-dependent kinase 2 (CDK2), protected zebrafish lateral-line neuromasts from cisplatin toxicity and, when delivered locally, protected adult mice and rats against cisplatin- and noise-induced hearing loss. CDK2-deficient mice displayed enhanced resistance to cisplatin toxicity in cochlear explants and to cisplatin- and noise-induced hearing loss in vivo. Mechanistically, we showed that kenpaullone directly inhibits CDK2 kinase activity and reduces cisplatin-induced mitochondrial production of reactive oxygen species, thereby enhancing cell survival. Our experiments have revealed the proapoptotic function of CDK2 in postmitotic cochlear cells and have identified promising therapeutics for preventing hearing loss.

Protective Effect of Acetyl-L-Carnitine Against Doxorubicin-induced Cardiotoxicity in Wistar Albino Rats

BACKGROUND AND AIMS

Anthracyclines are one of the most preferred agents in practical pediatric oncology despite their dose-dependent cardiotoxic effects. The aim of this study was to investigate whether or not acetyl-L-carnitine (ALCAR) has protective effects on doxorubicin (DOX)-induced cardiotoxicity.

METHODS

Wistar rats were divided into four groups; control, DOX, ALCAR and ALCAR+DOX. Rats in the first group were given saline on study days, whereas those in the second group were given a single dose of DOX on the 5^th day and saline on the other days. Rats in the third group were given ALCAR and those in the fourth group were given ALCAR on study days but also given only a single dose of DOX on the fifth day of the study. Ejection fractions (EF) were measured by echocardiography before and after drug administration. Heart tissues were evaluated by light and electron microscopy. Apoptotic cells were determined with TUNEL and caspase-3 staining.

RESULTS

DOX significantly decreased the EF values, whereas ALCAR did not. Cardiac functions were higher in the ALCAR+DOX group when compared to the DOX group. DOX administration caused a cardiac injury not only functionally, but also structurally, whereas ALCAR prevented it.

CONCLUSIONS

ALCAR has a capacity of preventing DOX-induced cardiac injury at both functional and structural levels.

CLM29, a multi-target pyrazolopyrimidine derivative, has anti-neoplastic activity in medullary thyroid cancer in vitro and in vivo

CLM29 (a pyrazolo[3,4-d]pyrimidine, that inhibits RET, epidermal growth factor receptor, vascular endothelial growth factor receptor, and has an anti-angiogenic activity) has anti-neoplastic activity in papillary dedifferentiated thyroid cancer. Here we tested CLM29 in medullary thyroid cancer (MTC), in primary MTC cells (P-MTC) obtained at surgery, and in TT cells harboring (C634W) RET mutation. CLM29 (10, 30, 50 μM) inhibited significantly (P<0.001) the proliferation, and increased the percentage of apoptotic P-MTC, TT and human dermal microvascular endothelial cells. The inhibition of proliferation by CLM29 was similar in P-MTC cells with/without RET mutation. TT cells were injected sc in CD nu/nu mice, and tumor masses became detectable between 20 and 30 days after xenotransplantation; CLM29 (50mg/kg/die) reduced significantly tumor growth and weight, and microvessel density. The anti-tumor activity of CLM29 has been shown in MTC in vitro, and in vivo, opening the way to a future clinical evaluation.

Motor and Behavioral Changes in Mice With Cisplatin-Induced Acute Renal Failure

We have previously shown that chronic renal failure in rats induces changes in motor activity and behavior. Similar work on the possible effects of acute renal failure (ARF) induced by cisplatin (CP) is lacking. This is the subject matter of the current work. CP was injected intraperitoneally (i.p.) at a single dose of 20 mg/kg to induce a state of ARF, and three days later, its effects on motor activity, thermal and chemical nociceptive tests, neuromuscular coordination, pentobarbitone-sleeping time, exploration activity and two depression models were investigated. The platinum concentration in the kidneys and brains of mice was also measured. The occurrence of CP-induced ARF was ascertained by standard physiological, biochemical and histo-pathological methods. CP induced all the classical biochemical, physiological and histopathological signs of ARF. The average renal platinum concentration of CP-treated mice was 5.16 ppm, but there was no measurable concentration of platinum in the whole brains. CP treatment significantly decreased motor and exploration activities, and increased immobility time in depression models, suggesting a possible depression-like state. There was also a significant decrease in neuromuscular coordination in CP-treated mice. CP, given at a nephrotoxic dose, induced several adverse motor and behavioral alterations in mice. Further behavioral tests and molecular and biochemical investigations in the brains of mice with CP-induced ARF are warranted.

Protective effect of acetyl-l-carnitine against cisplatin ototoxicity: role of apoptosis-related genes and pro-inflammatory cytokines

OBJECTIVES

Cisplatin is an anti-neoplastic agent treatment with which causes many side effects including ototoxicity. The aim of this study was to investigate whether acetyl-L-carnitine would have protective effects on cisplatin-induced ototoxicity in vitro, and if present, to reveal roles of apoptotic gene expressions and pro-inflammatory cytokines.

MATERIALS AND METHODS

House Ear Institute-Organ of Corti 1 cell line was used for this study. Apoptotic genes were evaluated with an apoptosis PCR array and pro-inflammatory cytokine levels were measured using ELISA.

RESULTS

Apoptotic cell death reduced by around 22% with acetyl-L-carnitine-cisplatin treatment compared to cisplatin alone. Genes displaying increase in expression of apoptosis, related to cisplatin treatment, were Casp8, Bcl10, Bcl2, Bcl2l1, Bcl2l2, Bid, Naip1, Bnip3l, Card6, Pak7, Cd40, Trp 53inp1, Cideb and Cd70. The acetyl-L-carnitine-cisplatin combination caused reduced expression of genes Casp8, Fas, Casp1, Tnfrsf11b, Tnfrsf10b induced by cisplatin. Acetyl-L-carnitine-cisplatin also caused reduced levels of IL-6, IL-1β and TNF-α, pro-inflammatory cytokines, induced by cisplatin.

CONCLUSION

Protective mechanisms of aceytl-L-carnitine against cisplatin induced apoptosis, mainly due to activation of anti-apoptotic Bcl family members' genes, and in an Akt-related gene expression dependent manner. This is the first study to indicate that acetyl-L-carnitine can be an effective agent against cisplatin ototoxicity in auditory cells, with induction of anti-apoptotic gene expression and attenuating levels of pro-inflammatory cytokines.

Potential nephroprotective effects of l-carnitine against drug-induced nephropathy: a review of literature

INTRODUCTION

Drug-induced nephrotoxicity (DIN) has been reported with a great number of medications and contributes to ∼ 20% of hospital admissions. l-carnitine owing to its antioxidant, anti-inflammatory and antiapoptotic properties has been proposed as a candidate for nephroprotection against DIN. Increasing need to use nephrotoxic therapeutic agents necessitated this review.

AREAS COVERED

The present review covers all published clinical and animal researches on nephroprotective effects of l-carnitine against DIN. l-carnitine significantly ameliorates DIN in animal studies especially against cisplatin-induced renal damage. Inhibition of reactive oxygen species generation, lipid peroxidation, matrix remodeling and apoptosis, anti-inflammatory properties and improvement in carnitine deficiency has been suggested as probable nephroprotective mechanisms of l-carnitine.

EXPERT OPINION

In spite of the evidences that support the nephroprotective effect of l-carnitine, the main problems in this area are inadequacy of reliable studies in humans and difficulty of translating the experimental results into clinical practice. In most of the described studies, l-carnitine treatment is prophylactically given. Use of l-carnitine as a prophylactic agent in clinical situations with an indication for nephrotoxic therapies is rarely possible except for contrast-induced nephrotoxicity. Development of validated early biomarkers to detect DIN may provide the opportunity to use prophylactic nephroprotective agents at golden time.

Mirtazapine protects against cisplatin-induced oxidative stress and DNA damage in the rat brain

AIM

Cisplatin chemotherapy is associated with neurotoxicity, and oxidative stress might play an important role in the pathogenesis. Mirtazapine may be a preventative agent via its less-known antioxidant properties. The aim of this study was to examine the potential chemoprotective effects of mirtazapine against cisplatin-induced oxidative stress and DNA damage.

METHODS

Twenty-four rats were divided equally into four groups: control; cisplatin (10 mg/kg i.p.); cisplatin plus mirtazapine (10-30 mg/kg, respectively i.p and p.o.); and mirtazapine (30 mg/kg p.o.). The rats were killed at the end of the 14th day of treatment. Brain tissue was examined with regard to antioxidant/oxidant biochemical parameters.

RESULTS

Although glutathione (tGSH) and nitric oxide (NO) end product mean scores were found to be statistically higher in the control group when compared with the cisplatin group (72.44% and 61.99% percentage change [PC], respectively), malondialdehyde (MDA), myeloperoxidase (MPO), and 8-hydroxyguanine (8-OH-GUA) mean scores were statistically lower in the control group in comparison with the cisplatin group (-55.48%, -67.99%, and -48.81% PC, respectively; P < 0.01). Finally, tGSH and NO end product levels were restored to normal (85.90% and 55.30% PC, respectively), and MDA, MPO, and 8-OH-GUA were significantly reduced by treatment with mirtazapine (-60.50%, -78.59%, and -38.10% PC, respectively; P < 0.01).

CONCLUSION

Mirtazapine has chemoprotective effects against cisplatin-induced oxidative stress and DNA damage in the rat brain, which may be attributed to its antioxidant capabilities. It would be useful to investigate whether cisplatin at the desired doses can be given concurrently with mirtazapine.

Mulberry leaf extract inhibits cancer cell stemness in neuroblastoma

Emerging evidence proposes that most cancers originate from a rare subpopulation of cells, called cancer stem cells (CSCs), which possess characteristics including differentiation, self-renewal, and tumorigenicity. Currently, available therapeutic agents cannot effectively eliminate CSCs. Therefore, the development of a nontoxic, natural treatment that can either overcome chemoresistance or promote the elimination of CSCs is highly desirable. The current study examined whether mulberry leaf (ML) ethanolic extract can effectively eliminate neuroblastoma stem cell-like population. Our data demonstrated that 10-40 μg/ml of ML extract significantly enhanced differentiation by elongating neurites and reducing clonogenicity and sphere formation as shown by the decreased expression of stem cell markers and increased expression of differentiation markers. The knock-down of delta-like 1 homologue by siRNA enhanced the significant inhibitory effects of 40 μg/ml of ML extract on colony formation. Furthermore, phosphorylation of the extracellular signal-regulated kinase (ERK) was increased by 20 or 40 μg/ml of ML extract and the MEK/ERK inhibitors completely blocked differentiation induced by the extract. Taken together, these findings provide experimental evidence that ML may have chemopreventive effects on neuroblastoma cells by inhibiting CSCs characteristics as well as regulating CSCs pathways, which may provide a therapeutic option for controlling the growth of neuroblastoma cells.

A review of the logistic role of L-carnitine in the management of radiation toxicity and radiotherapy side effects

Radiation therapy is a key modality in the treatment of different cancer types. Fatigue is the most common side effect of radiotherapy, while others include nausea, hair loss, skin irritation, anemia, infertility, cardiovascular disease, cognitive impairment and even the development of second cancers. Studies in experimental animals have shown protective effects of carnitine against exposure of various organs to ionizing radiation, whereas carnitine deficiency is known to enhance radiation-induced toxicity. This report summarizes the recent literature on the adverse effects of radiotherapy and the impact of radiation on carnitine homeostasis. Although some studies have demonstrated the prophylactic benefits of carnitine against the toxic effects of chemotherapy, the role of carnitine in the prognosis and management of cancer patients receiving radiotherapy is not clear and needs to be explored.

Metabolic signatures in apoptotic human cancer cell lines

Cancer cells have several specific metabolic features, which have been explored for targeted therapies. Agents that promote apoptosis in tumors are currently considered as a powerful tool for cancer therapeutics. The present study aimed to design a fast, reliable and robust system for metabolite measurements in cells lines to observe impact of apoptosis on the metabolome. For that purpose the NBS (newborn screen) mass spectrometry-based metabolomics assay was adapted for cell culture approach. In HEK 293 and in cancer cell lines HepG2, PC3, and MCF7 we searched for metabolic biomarkers of apoptosis differing from that of necrosis. Already nontreated cell lines revealed distinct concentrations of metabolites. Several metabolites indicative for apoptotic processes in cell culture including aspartate, glutamate, methionine, alanine, glycine, propionyl carnitine (C3-carnitine), and malonyl carnitine (C3DC-carnitine) were observed. In some cell lines metabolite changes were visible as early as 4 h after apoptosis induction and preceeding the detection by caspase 3/7 assay. We demonstrated for the first time that the metabolomic signatures might be used in the tests of efficacy of agents causing apoptosis in cell culture. These signatures could be obtained in fast high-throughput screening.

Role of carnitine in cancer chemotherapy-induced multiple organ toxicity

In the last few years, cancer chemotherapy has been successfully employed in the treatment of different types of human tumours. Unfortunately, the optimal clinical usefulness of this important treatment modality is usually limited secondary to the development of life-threatening multiple organ toxicity. Cancer chemotherapy may cause these toxic effects by mechanisms not involved in their anticancer activity that can severely affect the life of patients and represent a direct cause of death. Several experimental and clinical studies have demonstrated that some important anticancer drugs interfere with the absorption, synthesis, and excretion of carnitine in non-tumour tissues, resulting in a secondary carnitine deficiency which is reversed by carnitine treatment without affecting anticancer therapeutic efficacy. Prototypes of anticancer drugs that alter carnitine system are doxorubicin, cisplatin, carboplatin, oxaliplatin, cyclophosphamide and ifosfamide. Furthermore, cachectic cancer patients are especially at risk for carnitine deficiency due to decreased oral intake and/or increased renal losses. Altered serum and urine carnitine levels have been reported in cancer patients with various forms of malignant diseases. Recent studies in our laboratory have demonstrated that carnitine deficiency constitute a risk factor and should be viewed as a mechanism during development of oxazaphosphorines-induced cardiotoxicity in rats. Similarly, inhibition of gene expression of heart fatty acid-binding protein and organic cation/carnitine transporter in doxorubicin cardiomyopathic rat model has been reported. In view of these facts and in view of irreplaceability of these important anticancer drugs, this review aimed to highlight the role of carnitine depletion and supplementation during development of chemotherapy-induced multiple organ toxicity.

2-deoxy-D-glucose induces oxidative stress and cell killing in human neuroblastoma cells

Malignant cells have a demonstrably greater sensitivity to glucose deprivation-induced cytotoxicity than normal cells. This has been hypothesized to be due to a higher level of reactive oxygen species (ROS) production in cancer cells leading to the increased need for reducing equivalents, produced by glucose metabolism, to detoxify hydroperoxides. Because complete glucose deprivation cannot be achieved in vivo, it has been proposed that agents that antagonize glucose metabolism, such as 2-deoxy-D-glucose (2DG), can mimic in vitro glucose deprivation that selectively kills cancer cells by oxidative stress. To test this hypothesis, neuroblastoma cell lines were treated with 2DG and the effects on clonogenic survival and the distribution of cellular phenotypes among surviving colonies was determined. The results showed that all three major cell types found in neuroblastoma (Schwann, Neuronal and Intermediate) were sensitive to 2DG-induced clonogenic cell killing. Furthermore, treatment with the thiol antioxidant, N-acetyl cysteine or with polyethylene glycol-conjugated superoxide dismutase and catalase, protected neuroblastoma cells from 2DG-induced cell killing. Finally normal non-immortalized neural precursor cells were relatively resistant to 2DG-induced cell killing when compared to neuroblastoma cell lines. These results support the hypothesis that inhibitors of glucose metabolism could represent useful adjuvants in the treatment of neuroblastoma by selectively enhancing metabolic oxidative stress.