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Proceedings of the National Academy of... Oct 2015The most deadly complication of Plasmodium falciparum infection is cerebral malaria (CM) with a case fatality rate of 15-25% in African children despite effective...
The most deadly complication of Plasmodium falciparum infection is cerebral malaria (CM) with a case fatality rate of 15-25% in African children despite effective antimalarial chemotherapy. There are no adjunctive treatments for CM, so there is an urgent need to identify new targets for therapy. Here we show that the glutamine analog 6-diazo-5-oxo-L-norleucine (DON) rescues mice from CM when administered late in the infection a time at which mice already are suffering blood-brain barrier dysfunction, brain swelling, and hemorrhaging accompanied by accumulation of parasite-specific CD8(+) effector T cells and infected red blood cells in the brain. Remarkably, within hours of DON treatment mice showed blood-brain barrier integrity, reduced brain swelling, decreased function of activated effector CD8(+) T cells in the brain, and levels of brain metabolites that resembled those in uninfected mice. These results suggest DON as a strong candidate for an effective adjunctive therapy for CM in African children.
Topics: Animals; Antimalarials; Blood-Brain Barrier; Diazooxonorleucine; Glutamine; Malaria, Cerebral; Malaria, Falciparum; Mice
PubMed: 26438846
DOI: 10.1073/pnas.1516544112 -
BioMed Research International 2015Abnormal metabolism is another cancer hallmark. The two most characterized altered metabolic pathways are high rates of glycolysis and glutaminolysis, which are natural... (Review)
Review
Abnormal metabolism is another cancer hallmark. The two most characterized altered metabolic pathways are high rates of glycolysis and glutaminolysis, which are natural targets for cancer therapy. Currently, a number of newer compounds to block glycolysis and glutaminolysis are being developed; nevertheless, lonidamine and 6-diazo-5-oxo-L-norleucine (DON) are two old drugs well characterized as inhibitors of glycolysis and glutaminolysis, respectively, whose clinical development was abandoned years ago when the importance of cancer metabolism was not fully appreciated and clinical trial methodology was less developed. In this review, a PubMed search using the words lonidamine and 6-diazo-5-oxo-L-norleucine (DON) was undertaken to analyse existing information on the preclinical and clinical studies of these drugs for cancer treatment. Data show that they exhibit antitumor effects; besides there is also the suggestion that they are synergistic. We conclude that lonidamine and DON are safe and potentially effective drugs that need to be reevaluated in combination as metabolic therapy of cancer.
Topics: Antineoplastic Combined Chemotherapy Protocols; Clinical Trials as Topic; Diazooxonorleucine; Humans; Indazoles; Neoplasms
PubMed: 26425550
DOI: 10.1155/2015/690492 -
Oncotarget Sep 2015Cancer cells exhibit altered metabolism including aerobic glycolysis that channels several glycolytic intermediates into de novo purine biosynthetic pathway. We...
Cancer cells exhibit altered metabolism including aerobic glycolysis that channels several glycolytic intermediates into de novo purine biosynthetic pathway. We discovered increased expression of phosphoribosyl amidotransferase (PPAT) and phosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS) enzymes of de novo purine biosynthetic pathway in lung adenocarcinomas. Transcript analyses from next-generation RNA sequencing and gene expression profiling studies suggested that PPAT and PAICS can serve as prognostic biomarkers for aggressive lung adenocarcinoma. Immunohistochemical analysis of PAICS performed on tissue microarrays showed increased expression with disease progression and was significantly associated with poor prognosis. Through gene knockdown and over-expression studies we demonstrate that altering PPAT and PAICS expression modulates pyruvate kinase activity, cell proliferation and invasion. Furthermore we identified genomic amplification and aneuploidy of the divergently transcribed PPAT-PAICS genomic region in a subset of lung cancers. We also present evidence for regulation of both PPAT and PAICS and pyruvate kinase activity by L-glutamine, a co-substrate for PPAT. A glutamine antagonist, 6-Diazo-5-oxo-L-norleucine (DON) blocked glutamine mediated induction of PPAT and PAICS as well as reduced pyruvate kinase activity. In summary, this study reveals the regulatory mechanisms by which purine biosynthetic pathway enzymes PPAT and PAICS, and pyruvate kinase activity is increased and exposes an existing metabolic vulnerability in lung cancer cells that can be explored for pharmacological intervention.
Topics: Adenocarcinoma; Aged; Amidophosphoribosyltransferase; Aneuploidy; Animals; Biomarkers, Tumor; Carboxy-Lyases; Cell Line, Tumor; Cell Proliferation; Chickens; Diazooxonorleucine; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Glutamine; Humans; Lung Neoplasms; Male; Mice; Middle Aged; Neoplasm Invasiveness; Neoplasm Transplantation; Oligonucleotide Array Sequence Analysis; Peptide Synthases; Prognosis; Purines
PubMed: 26140362
DOI: 10.18632/oncotarget.4352 -
Journal of Neurovirology Apr 2015Recovery from encephalomyelitis induced by infection with mosquito-borne alphaviruses is associated with a high risk of lifelong debilitating neurological deficits....
Recovery from encephalomyelitis induced by infection with mosquito-borne alphaviruses is associated with a high risk of lifelong debilitating neurological deficits. Infection of mice with the prototypic alphavirus, Sindbis virus, provides an animal model with which to study disease mechanisms and examine potential therapeutics. Infectious virus is cleared from the brain within a week after infection, but viral RNA is cleared slowly and persists for the life of the animal. However, no studies have examined the effect of infection on neurocognitive function over time. In the present study, we examined neurocognitive function at different phases of infection in 5-week-old C57BL/6 mice intranasally inoculated with Sindbis virus. At the peak of active virus infection, mice demonstrated hyperactivity, decreased anxiety, and marked hippocampal-dependent memory deficits, the latter of which persisted beyond clearance of infectious virus and resolution of clinical signs of disease. Previous studies indicate that neuronal damage during alphavirus encephalomyelitis is primarily due to inflammatory cell infiltration and glutamate excitotoxicity rather than directly by virus infection. Therefore, mice were treated with 6-diazo-5-oxo-l-norleucine (DON), a glutamine antagonist that can suppress both the immune response and excitotoxicity. Treatment with DON decreased inflammatory cell infiltration and cell death in the hippocampus and partially prevented development of clinical signs and neurocognitive impairment despite the presence of infectious virus and high viral RNA levels. This study presents the first report of neurocognitive sequelae in mice with alphavirus encephalomyelitis and provides a model system for further elucidation of the pathogenesis of virus infection and assessment of potential therapies.
Topics: Alphavirus Infections; Animals; Antimetabolites, Antineoplastic; Behavior, Animal; Diazooxonorleucine; Disease Models, Animal; Encephalitis, Viral; Enzyme-Linked Immunosorbent Assay; Glutamine; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Motor Activity; Sindbis Virus
PubMed: 25645378
DOI: 10.1007/s13365-015-0314-6 -
PloS One 2015Neuroblastomas (NBL) and Ewing's sarcomas (EWS) together cause 18% of all pediatric cancer deaths. Though there is growing interest in targeting the dysregulated...
Neuroblastomas (NBL) and Ewing's sarcomas (EWS) together cause 18% of all pediatric cancer deaths. Though there is growing interest in targeting the dysregulated metabolism of cancer as a therapeutic strategy, this approach has not been fully examined in NBL and EWS. In this study, we first tested a panel of metabolic inhibitors and identified the glutamine antagonist 6-diazo-5-oxo-L-norleucine (DON) as the most potent chemotherapeutic across all NBL and EWS cell lines tested. Myc, a master regulator of metabolism, is commonly overexpressed in both of these pediatric malignancies and recent studies have established that Myc causes cancer cells to become "addicted" to glutamine. We found DON strongly inhibited tumor growth of multiple tumor lines in mouse xenograft models. In vitro, inhibition of caspases partially reversed the effects of DON in high Myc expressing cell lines, but not in low Myc expressing lines. We further showed that induction of apoptosis by DON in Myc-overexpressing cancers is via the pro-apoptotic factor Bax. To relieve inhibition of Bax, we tested DON in combination with the Bcl-2 family antagonist navitoclax (ABT-263). In vitro, this combination caused an increase in DON activity across the entire panel of cell lines tested, with synergistic effects in two of the N-Myc amplified neuroblastoma cell lines. Our study supports targeting glutamine metabolism to treat Myc overexpressing cancers, such as NBL and EWS, particularly in combination with Bcl-2 family antagonists.
Topics: Aniline Compounds; Animals; Antimetabolites, Antineoplastic; Apoptosis; Bone Neoplasms; Caspases; Cell Line, Tumor; Cell Proliferation; Diazooxonorleucine; Drug Synergism; Glutamine; Humans; Mice; Neuroblastoma; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-myc; Sarcoma, Ewing; Sulfonamides; Xenograft Model Antitumor Assays
PubMed: 25615615
DOI: 10.1371/journal.pone.0116998 -
Analytical Biochemistry Apr 2015Glutamine is an abundant amino acid that plays pivotal roles in cell growth, cell metabolism, and neurotransmission. Dysregulation of glutamine-using pathways has been...
Glutamine is an abundant amino acid that plays pivotal roles in cell growth, cell metabolism, and neurotransmission. Dysregulation of glutamine-using pathways has been associated with pathological conditions such as cancer and neurodegenerative diseases. 6-Diazo-5-oxo-l-norleucine (DON) is a reactive glutamine analog that inhibits enzymes affecting glutamine metabolism such as glutaminase, 2-N-amidotransferase, l-asparaginase, and several enzymes involved in pyrimidine and purine de novo synthesis. As a result, DON is actively used in preclinical models of cancer and neurodegenerative disease. Moreover, there have been several clinical trials using DON to treat a variety of cancers. Considerations of dose and exposure are especially important with DON treatment due to its narrow therapeutic window and significant side effects. Consequently, a robust quantification bioassay is of interest. DON is a polar unstable molecule that has made quantification challenging. Here we report on the characterization of a bioanalytical method to quantify DON in tissue samples involving DON derivatization with 3 N HCl in butanol. The derivatized product is lipophilic and stable. Detection of this analyte by mass spectrometry is fast and specific and can be used to quantify DON in plasma and brain tissue with a limit of detection at the low nanomolar level.
Topics: 1-Butanol; Animals; Brain; Chlorine; Chromatography, High Pressure Liquid; Diazooxonorleucine; Esters; Male; Mice, Inbred C57BL; Reference Standards; Tandem Mass Spectrometry; Time Factors
PubMed: 25584882
DOI: 10.1016/j.ab.2015.01.001