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Nature Metabolism Dec 2020In non-small-cell lung cancer (NSCLC), concurrent mutations in the oncogene KRAS and the tumour suppressor STK11 (also known as LKB1) encoding the kinase LKB1 result in...
In non-small-cell lung cancer (NSCLC), concurrent mutations in the oncogene KRAS and the tumour suppressor STK11 (also known as LKB1) encoding the kinase LKB1 result in aggressive tumours prone to metastasis but with liabilities arising from reprogrammed metabolism. We previously demonstrated perturbed nitrogen metabolism and addiction to an unconventional pathway of pyrimidine synthesis in KRAS/LKB1 co-mutant cancer cells. To gain broader insight into metabolic reprogramming in NSCLC, we analysed tumour metabolomes in a series of genetically engineered mouse models with oncogenic KRAS combined with mutations in LKB1 or p53. Metabolomics and gene expression profiling pointed towards activation of the hexosamine biosynthesis pathway (HBP), another nitrogen-related metabolic pathway, in both mouse and human KRAS/LKB1 co-mutant tumours. KRAS/LKB1 co-mutant cells contain high levels of HBP metabolites, higher flux through the HBP pathway and elevated dependence on the HBP enzyme glutamine-fructose-6-phosphate transaminase [isomerizing] 2 (GFPT2). GFPT2 inhibition selectively reduced KRAS/LKB1 co-mutant tumour cell growth in culture, xenografts and genetically modified mice. Our results define a new metabolic vulnerability in KRAS/LKB1 co-mutant tumours and provide a rationale for targeting GFPT2 in this aggressive NSCLC subtype.
Topics: AMP-Activated Protein Kinase Kinases; Animals; Antineoplastic Agents; Azaserine; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing); Hexosamines; Humans; Lung Neoplasms; Metabolic Networks and Pathways; Metabolomics; Mice; Mutation; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins p21(ras); Survival Analysis; Tumor Stem Cell Assay
PubMed: 33257855
DOI: 10.1038/s42255-020-00316-0 -
Acta Biochimica Et Biophysica Sinica Mar 2023Ferroptosis is a type of programmed cell death closely related to amino acid metabolism. Pancreatic cancer cells have a strong dependence on glutamine, which serves as a...
Ferroptosis is a type of programmed cell death closely related to amino acid metabolism. Pancreatic cancer cells have a strong dependence on glutamine, which serves as a carbon and nitrogen substrate to sustain rapid growth. Glutamine also aids in self-protection mechanisms. However, the effect of glutamine on ferroptosis in pancreatic cancer remains largely unknown. Here, we aim to explore the association between ferroptosis and glutamine deprivation in pancreatic cancer. The growth of pancreatic cancer cells in culture media with or without glutamine is evaluated using Cell Counting Kit-8. Reactive oxygen species (ROS) are measured by 2',7'-dichlorodihydrofluorescein diacetate staining. Ferroptosis is assessed by BODIPY-C11 dye using confocal microscopy and flow cytometry. Amino acid concentrations are measured using ultrahigh-performance liquid chromatography-tandem mass spectrometry. Isotope-labelled metabolic flux analysis is performed to track the metabolic flow of glutamine. Additionally, RNA sequencing is performed to analyse the genetic alterations. Glutamine deprivation inhibits pancreatic cancer growth and induces ferroptosis both and . Additionally, glutamine decreases ROS formation via glutathione production in pancreatic cancer cells. Interestingly, glutamine inhibitors (diazooxonorleucine and azaserine) promotes ROS formation and ferroptosis in pancreatic cancer cells. Furthermore, ferrostatin, a ferroptosis inhibitor, rescues ferroptosis in pancreatic cancer cells. Glutamine deprivation leads to changes in molecular pathways, including cytokine-cytokine receptor interaction pathways ( , , , , , and ). Thus, exogenous glutamine is required for the detoxification of ROS in pancreatic cancer cells, thereby preventing ferroptosis.
Topics: Humans; Ferroptosis; Glutamine; Reactive Oxygen Species; Apoptosis; Pancreatic Neoplasms
PubMed: 36942991
DOI: 10.3724/abbs.2023029 -
Chemical Research in Toxicology Jun 2021The -alkylguanosine adduct -carboxymethyldeoxyguanosine (-CMdG) has been detected at elevated levels in blood and tissue samples from colorectal cancer patients and from...
The -alkylguanosine adduct -carboxymethyldeoxyguanosine (-CMdG) has been detected at elevated levels in blood and tissue samples from colorectal cancer patients and from healthy volunteers after consuming red meat. The diazo compound l-azaserine leads to the formation of -CMdG as well as the corresponding methyl adduct -methyldeoxyguanosine (-MedG) in cells and is therefore in wide use as a chemical probe in cellular studies concerning DNA damage and mutation. However, there remain knowledge gaps concerning the chemical basis of DNA adduct formation by l-azaserine. To characterize -CMdG formation by l-azaserine, we carried out a combination of chemical and enzymatic stability and reactivity studies supported by liquid chromatography tandem mass spectrometry for the simultaneous quantification of -CMdG and -MedG. We found that l-azaserine is stable under physiological and alkaline conditions as well as in active biological matrices but undergoes acid-catalyzed hydrolysis. We show, for the first time, that l-azaserine reacts directly with guanosine (dG) and oligonucleotides to form an -serine-CMdG (-Ser-CMdG) adduct. Moreover, by characterizing the reaction of dG with l-azaserine, we demonstrate that -Ser-CMdG forms as an intermediate that spontaneously decomposes to form -CMdG. Finally, we quantified levels of -CMdG and -MedG in a human cell line exposed to l-azaserine and found maximal adduct levels after 48 h. The findings of this work elucidate the chemical basis of how l-azaserine reacts with deoxyguanosine and support its use as a chemical probe for N-nitroso compound exposure in carcinogenesis research, particularly concerning the identification of pathways and factors that promote adduct formation.
Topics: Alkylation; Animals; Azaserine; Cells, Cultured; Deoxyguanosine; Humans; Hydrogen-Ion Concentration; Molecular Structure; Swine
PubMed: 34061515
DOI: 10.1021/acs.chemrestox.0c00471 -
Nature Communications Jan 2018AMP-activated protein kinase (AMPK) has been shown to inhibit cardiac hypertrophy. Here, we show that submaximal AMPK activation blocks cardiomyocyte hypertrophy without...
AMP-activated protein kinase (AMPK) has been shown to inhibit cardiac hypertrophy. Here, we show that submaximal AMPK activation blocks cardiomyocyte hypertrophy without affecting downstream targets previously suggested to be involved, such as p70 ribosomal S6 protein kinase, calcineurin/nuclear factor of activated T cells (NFAT) and extracellular signal-regulated kinases. Instead, cardiomyocyte hypertrophy is accompanied by increased protein O-GlcNAcylation, which is reversed by AMPK activation. Decreasing O-GlcNAcylation by inhibitors of the glutamine:fructose-6-phosphate aminotransferase (GFAT), blocks cardiomyocyte hypertrophy, mimicking AMPK activation. Conversely, O-GlcNAcylation-inducing agents counteract the anti-hypertrophic effect of AMPK. In vivo, AMPK activation prevents myocardial hypertrophy and the concomitant rise of O-GlcNAcylation in wild-type but not in AMPKα2-deficient mice. Treatment of wild-type mice with O-GlcNAcylation-inducing agents reverses AMPK action. Finally, we demonstrate that AMPK inhibits O-GlcNAcylation by mainly controlling GFAT phosphorylation, thereby reducing O-GlcNAcylation of proteins such as troponin T. We conclude that AMPK activation prevents cardiac hypertrophy predominantly by inhibiting O-GlcNAcylation.
Topics: AMP-Activated Protein Kinases; Acetylglucosamine; Acylation; Animals; Animals, Newborn; Azaserine; Azo Compounds; Biphenyl Compounds; Cardiomegaly; Enzyme Activation; Enzyme Activators; Gene Expression Regulation; Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing); Glycosylation; Heart Ventricles; Male; Mice; Mice, Knockout; Myocardium; Myocytes, Cardiac; Nitrogenous Group Transferases; Norleucine; Phosphorylation; Primary Cell Culture; Pyrones; Rats; Rats, Wistar; Signal Transduction; Thiophenes; Troponin T
PubMed: 29371602
DOI: 10.1038/s41467-017-02795-4 -
Asian Pacific Journal of Cancer... Apr 2023Hydatid cyst is a zoonotic infestation caused by Echinococcus granulosus, and it is known that some parasites found in humans cause cancer in humans or some may have a...
Hydatid cyst is a zoonotic infestation caused by Echinococcus granulosus, and it is known that some parasites found in humans cause cancer in humans or some may have a protective effect against cancer. Cancer is one of the most serious health problems of today and it has been shown in some studies that parasites such as Echinococcus granulosus can have an inhibitory effect. The aim of this study was determined as whether Echinococcus granulosus has an inhibitory effect on exocrine pancreatic cancer with the help of the azaserine-rat model used in different cancer studies. Material and Methods: During experimental process a total of 45 male Wistar rats used, 14-day-old male Wistar rats were divided into groups according to the experimental protocol, administered azaserine injection protocol or kept as a control group without azaserine injection. Animals are grouped as Group 1, Control Group (group not treated with Azaserine and not injected with protoscolex.) (E-A-) (n=7); Group 2, Group injected with (IP) Azaserine only (30mg/kg) (E-A+) (n=8);Group 3, Group injected (IP) with protoscolex suspension of 1 cc only (E+A-) (n=15);Group 4, Group injected both Azaserine (IP) and protoscolex suspension (IP) (E+A+) (n=15). Atypical Acinar Cell Foci (AACF) load in the exocrine pancreas of each rat was measured quantitatively with the help of a video image analyzer and the AACF load was calculated with the help of a mathematical model. Results: Findings showed that the Atypical Acinar Cell Foci (AACF) burden was statistically significantly lower in the Azaserine+ protoscolex (Azaserine-injected-protoscolex-implanted) rat group compared to the other groups, suggesting that Echinococcosis in the azaserine-rat model could inhibit the development of precursor foci of neoplastic changes in the exocrine pancreas. Conclusion: The most significant aspect of our study is that it contributes new insights into the controversy that Echinococcosis suppresses pancreatic cancer.
Topics: Humans; Rats; Male; Animals; Rats, Wistar; Echinococcus granulosus; Azaserine; Pancreatic Neoplasms; Echinococcosis; Pancreas
PubMed: 37116153
DOI: 10.31557/APJCP.2023.24.4.1307 -
Metabolites Apr 2021Disrupted endothelial metabolism is linked to endothelial dysfunction and cardiovascular disease. Targeted metabolic inhibitors are potential therapeutics; however,...
Disrupted endothelial metabolism is linked to endothelial dysfunction and cardiovascular disease. Targeted metabolic inhibitors are potential therapeutics; however, their systemic impact on endothelial metabolism remains unknown. In this study, we combined stable isotope labeling with C metabolic flux analysis (C MFA) to determine how targeted inhibition of the polyol (fidarestat), pentose phosphate (DHEA), and hexosamine biosynthetic (azaserine) pathways alters endothelial metabolism. Glucose, glutamine, and a four-carbon input to the malate shuttle were important carbon sources in the baseline human umbilical vein endothelial cell (HUVEC) C MFA model. We observed two to three times higher glutamine uptake in fidarestat and azaserine-treated cells. Fidarestat and DHEA-treated HUVEC showed decreased C enrichment of glycolytic and TCA metabolites and amino acids. Azaserine-treated HUVEC primarily showed C enrichment differences in UDP-GlcNAc. C MFA estimated decreased pentose phosphate pathway flux and increased TCA activity with reversed malate shuttle direction in fidarestat and DHEA-treated HUVEC. In contrast, C MFA estimated increases in both pentose phosphate pathway and TCA activity in azaserine-treated cells. These data show the potential importance of endothelial malate shuttle activity and suggest that inhibiting glycolytic side branch pathways can change the metabolic network, highlighting the need to study systemic metabolic therapeutic effects.
PubMed: 33917224
DOI: 10.3390/metabo11040226 -
Pharmaceuticals (Basel, Switzerland) Jun 2021The flavonolignan silibinin, the major bioactive component of the silymarin extract of (milk thistle) seeds, is gaining traction as a novel anti-cancer therapeutic.... (Review)
Review
The flavonolignan silibinin, the major bioactive component of the silymarin extract of (milk thistle) seeds, is gaining traction as a novel anti-cancer therapeutic. Here, we review the historical developments that have laid the groundwork for the evaluation of silibinin as a chemopreventive and therapeutic agent in human lung cancer, including translational insights into its mechanism of action to control the aggressive behavior of lung carcinoma subtypes prone to metastasis. First, we summarize the evidence from chemically induced primary lung tumors supporting a role for silibinin in lung cancer prevention. Second, we reassess the preclinical and clinical evidence on the effectiveness of silibinin against drug resistance and brain metastasis traits of lung carcinomas. Third, we revisit the transcription factor STAT3 as a central tumor-cell intrinsic and microenvironmental target of silibinin in primary lung tumors and brain metastasis. Finally, by unraveling the selective vulnerability of silibinin-treated tumor cells to drugs using CRISPR-based chemosensitivity screenings (e.g., the hexosamine biosynthesis pathway inhibitor azaserine), we illustrate how the therapeutic use of silibinin against targetable weaknesses might be capitalized in specific lung cancer subtypes (e.g., co-mutant tumors). Forthcoming studies should take up the challenge of developing silibinin and/or next-generation silibinin derivatives as novel lung cancer-preventive and therapeutic biomolecules.
PubMed: 34208282
DOI: 10.3390/ph14060559 -
Journal of Cancer Research and... 2019The effect of acetylsalicylic acid (ASA) on thiol levels was studied in a rat model of azaserine carcinogenesis.
AIM
The effect of acetylsalicylic acid (ASA) on thiol levels was studied in a rat model of azaserine carcinogenesis.
MATERIALS AND METHODS
ASA and azaserine were applied to the animals to research changes in cellular sulfhydryl (-SH) content and variations in free and protein-bound molecules containing the -SH group. Such effects in rats injected with azaserine were investigated at low (200 ppm) and high (400 ppm) concentrations of ASA over a relatively short (6 months) and a relatively long (12 months) period.
RESULTS
Changes in the hepatic, pancreatic, and renal -SH contents were also determined.
CONCLUSION
Compared to the other tissues studied, the liver contained the highest levels of both free and protein-bound -SH.
Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Azaserine; Carcinogens; Dose-Response Relationship, Drug; Humans; Kidney; Liver; Male; Neoplasms; Neoplasms, Experimental; Pancreas; Rats; Rats, Wistar; Sulfhydryl Compounds; Treatment Outcome
PubMed: 30880783
DOI: 10.4103/jcrt.JCRT_1319_16 -
DNA Repair Feb 2022Distinct cellular DNA damage repair pathways maintain the structural integrity of DNA and protect it from the mutagenic effects of genotoxic exposures and processes. The...
Distinct cellular DNA damage repair pathways maintain the structural integrity of DNA and protect it from the mutagenic effects of genotoxic exposures and processes. The occurrence of O-carboxymethylguanine (O-CMG) has been linked to meat consumption and hypothesized to contribute to the development of colorectal cancer. However, the cellular fate of O-CMG is poorly characterized and there is contradictory data in the literature as to how repair pathways may protect cells from O-CMG mutagenicity. To better address how cells detect and remove O-CMG, we evaluated the role of two DNA repair pathways in counteracting the accumulation and toxic effects of O-CMG. We found that cells deficient in either the direct repair protein O-methylguanine-DNA methyltransferase (MGMT), or key components of the nucleotide excision repair (NER) pathway, accumulate higher levels O-CMG DNA adducts than wild type cells. Furthermore, repair-deficient cells were more sensitive to carboxymethylating agents and displayed an increased mutation rate. These findings suggest that a combination of direct repair and NER circumvent the effects O-CMG DNA damage.
Topics: DNA; DNA Adducts; DNA Damage; DNA Repair; Mutagenesis; Mutagens; O(6)-Methylguanine-DNA Methyltransferase
PubMed: 35030424
DOI: 10.1016/j.dnarep.2021.103262 -
Medical Science Monitor : International... May 2016BACKGROUND Diabetic retinopathy (DR) is a progressive neurodegenerative disease with early-stage symptoms such as dysfunction of Muller cells, which leads to ganglion...
BACKGROUND Diabetic retinopathy (DR) is a progressive neurodegenerative disease with early-stage symptoms such as dysfunction of Muller cells, which leads to ganglion cell death. Its pathogenesis is probably associated with oxidative stress and a recently discovered protein, thioredoxin-interacting protein (TXNIP). MATERIAL AND METHODS To explore the role of TXNIP in DR, we cultured Muller cells under diabetic conditions, and then used immunohistochemistry, Western blot, and RT-PCR to detect the expression level of TXNIP under diabetic conditions. We demonstrated the expression level of glutamine synthetase (GS) when TXNIP was inhibited. To explore the potential pathway of TXNIP-induced cell damage in DR, we confirmed the role of IL-1β under diabetic conditions. RESULTS Diabetes induces TXNIP expressions at mRNA levels, but shows the opposite effect on GS. IL-1β plays an important role in this pathway. Azaserine effectively increased the expression of GS via attenuating the expression of TXNIP. CONCLUSIONS This study demonstrates the role of TXNIP and its mechanism in DR, provides a possible treatment for DR, and lays a new theoretical foundation for the clinical treatment of DR and other diabetic microvascular changes.
Topics: Animals; Azaserine; Carrier Proteins; Cells, Cultured; Diabetes Mellitus, Experimental; Ependymoglial Cells; Fluorescent Antibody Technique; Gene Expression Regulation; Glucose; Glutamate-Ammonia Ligase; Interleukin-1beta; Mice; Oxidative Stress; RNA, Messenger; Retina; Thioredoxins
PubMed: 27131835
DOI: 10.12659/msm.895916