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1.
Tumors can use metabolic reprogramming to survive nutrient stress. Epigenetic regulators play a critical role in metabolic adaptation. Here we screened a sgRNA library to identify epigenetic regulators responsible for the vulnerability of colorectal cancer (CRC) cells to glucose deprivation and found that more EZH2-knockout cells survived glucose deprivation. Then, we showed that EZH2 expression was significantly downregulated in response to glucose deprivation in a glucose-sensitive CRC cell line, and EZH2-knockdown cells were more resistant to glucose deprivation. Mechanistically, EZH2 deficiency upregulated the expression of glutaminase (GLS) and promoted the production of glutamate, which in turn led to increased synthesis of intracellular glutathione (GSH) and eventually attenuated the reactive oxygen species (ROS)-mediated cell death induced by glucose deprivation. Although EZH2 functioned as an oncogene in cancer progression and EZH2 knockout abolished colorectal cancer development in a mouse model, here we revealed a mechanistic link between EZH2 and metabolic reprogramming via the direct regulation of GLS expression and observed a negative correlation between EZH2 and GLS expression in colorectal cancer tissues. These findings further confirmed the importance of heterogeneity, provided an explanation for the clinical tolerance of cancer cells to EZH2 inhibitors from the perspective of metabolism, and proposed the possibility of combining EZH2 inhibitors and glutamine metabolism inhibitors for the treatment of cancer.Subject terms: Cancer metabolism, Colon cancer  相似文献   

2.
A major metabolic aberration associated with cancer is a change in glucose metabolism. Isoform selection of the glycolytic enzyme pyruvate kinase has been implicated in the metabolic phenotype of cancer cells, and specific pyruvate kinase isoforms have been suggested to support divergent energetic and biosynthetic requirements of cells in tumors and normal tissues. PKM2 isoform expression has been closely linked to embryogenesis, tissue repair, and cancer. In contrast, forced expression of the PKM1 isoform has been associated with reduced tumor cell proliferation. Here, we discuss the role that PKM2 plays in cells and provide a historical perspective for how the study of PKM2 has contributed to understanding cancer metabolism. We also review recent studies that raise important questions with regard to the role of PKM2 in both normal and cancer cell metabolism.  相似文献   

3.
蛋白质泛素化是一种可逆的蛋白质翻译后修饰,在信号转导和蛋白质稳定性调控中发挥关键作用。去泛素化酶调控在许多种肿瘤中的作用机制尚不清楚。本文对63种去泛素化酶在肝细胞癌病人的生存和预后进行分析,发现去泛素化酶JOSD2(josephin domain containing 2)在肝细胞癌组织中表达显著高于癌旁(P<0.0001),且与总生存期相关(P<0.05)。JOSD2属于去泛素化酶MJD(machado josephin domain)亚家族成员,该家族其它成员与肝细胞癌发生无显著的相关性。对TCGA(The Cancer Genome Atlas)数据中JOSD2高表达样本和低表达样本的差异基因进行功能富集分析,显示JOSD2高表达样本中与细胞增殖相关通路显著富集(FDR<0.05)。在肝癌细胞系中过表达JOSD2,发现其能促进肝癌细胞的存活、迁移和侵袭(P<0.01)。综上所述,本文发现去泛素化酶JOSD2在肝细胞癌组织中高表达,高表达JOSD2的肝细胞癌病人总生存期显著降低(P=0.041),过表达JOSD2能促进肝癌细胞的存活和转移,提示JOSD2可能促进肝细胞癌的转移。  相似文献   

4.
Cancer cell metabolism is largely controlled by oncogenic signals and nutrient availability. Here, we highlighted that the glucocorticoid-induced leucine zipper (GILZ), an intracellular protein influencing many signaling pathways, reprograms cancer cell metabolism to promote proliferation. We provided evidence that GILZ overexpression induced a significant increase of mitochondrial oxidative phosphorylation as evidenced by the augmentation in basal respiration, ATP-linked respiration as well as respiratory capacity. Pharmacological inhibition of glucose, glutamine and fatty acid oxidation reduced the activation of GILZ-induced mitochondrial oxidative phosphorylation. At glycolysis level, GILZ-overexpressing cells enhanced the expression of glucose transporters in their plasmatic membrane and showed higher glycolytic reserve. 1H NMR metabolites quantification showed an up-regulation of amino acid biosynthesis. The GILZ-induced metabolic reprograming is present in various cancer cell lines regardless of their driver mutations status and is associated with higher proliferation rates persisting under metabolic stress conditions. Interestingly, high levels of OXPHOS made GILZ-overexpressing cells vulnerable to cell death induced by mitochondrial pro-oxidants. Altogether, these data indicate that GILZ reprograms cancer metabolism towards mitochondrial OXPHOS and sensitizes cancer cells to mitochondria-targeted drugs with pro-oxidant activities.  相似文献   

5.
Cancer cells are highly dependent on glycolysis to supply the energy and intermediates required for cell growth and proliferation. The enzyme 6-phosphofructo-1-kinase (PFK) is critical for glycolysis, and its activity is directly correlated with cellular glucose consumption. Resveratrol is a potential anti-tumoral drug that decreases glucose metabolism and viability in cancer cells. However, the mechanism involved in resveratrol-mediated anti-tumor activity is not entirely clear. In this work, it is demonstrated that resveratrol decreases viability, glucose consumption and ATP content in the human breast cancer cell line MCF-7. These effects are directly correlated with PFK inhibition by resveratrol in these cells. Moreover, resveratrol directly inhibits purified PFK, promoting the dissociation of the enzyme from fully active tetramers into less active dimers. This effect is exacerbated by known negative regulators of the enzyme, such as ATP and citrate. On the other hand, positive modulators that stabilize the tetrameric form of the enzyme, such as fructose-2,6-bisphosphate and ADP, prevent the inhibition of PFK activity by resveratrol, an effect not observed with increased pH. In summary, our results provide evidence that resveratrol directly inhibits PFK activity, therefore disrupting glucose metabolism and reducing viability in cancer cells.  相似文献   

6.
Iqbal MA  Bamezai RN 《PloS one》2012,7(5):e36764
Metabolism of cancer cells with pyruvate kinase M2 (PKM2) at its centre stage has assumed a prime significance in cancer research in recent times. Cancer cell metabolism, characterized by enhanced glucose uptake, production of lactate and anabolism is considered an ideal target for therapeutic interventions. Expression of PKM2 switches metabolism in favor of cancer cells, therefore, the present study was designed to investigate the hitherto unknown effect of resveratrol, a phytoalexin, on PKM2 expression and resultant implications on cancer metabolism. We observed that resveratrol down-regulated PKM2 expression by inhibiting mTOR signaling and suppressed cancer metabolism, adjudged by decreased glucose uptake, lactate production (aerobic glycolysis) and reduced anabolism (macromolecule synthesis) in various cancer cell lines. A contingent decrease in intracellular levels of ribose-5-phosphate (R5P), a critical intermediate of pentose phosphate pathway, accounted for a reduced anabolism. Consequently, the state of suppressed cancer metabolism resulted in decreased cellular proliferation. Interestingly, shRNA-mediated silencing of PKM2 inhibited glucose uptake and lactate production, providing evidence for the critical role of PKM2 and its mediation in the observed effects of resveratrol on cancer metabolism. Further, an over-expression of PKM2 abolished the observed effects of resveratrol, signifying the role of PKM2 downregulation as a critical function of resveratrol. The study reports a novel PKM2-mediated effect of resveratrol on cancer metabolism and provides a new dimension to its therapeutic potential.  相似文献   

7.
为了探讨miR-148a及己糖激酶2(hexokinase 2,HK2)基因对人乳腺癌细胞糖酵解代谢途径的影响和可能机制,利用实时荧光定量PCR(real-time fluorescent quantitative PCR,qRT-PCR)检测多种乳腺癌细胞系中miR-148a的表达量,从中筛选miR-148a表达量相对较低的乳腺癌细胞系作为研究对象。再通过观察miR-148a表达量的变化对乳腺癌细胞葡萄糖摄取量、乳酸生成量和细胞增殖指标的影响,以探究miR-148a对乳腺癌细胞糖代谢能力的影响。随后,通过TargetScan在线数据库预测miR-148a和HK2基因的靶向关系,再通过双荧光素酶报告实验、Western免疫印迹以及基因回复实验进行验证,以进一步明确miR-148a和HK2在乳腺癌细胞的糖酵解代谢途径中的作用机制。通过qRT-PCR发现miR-148a在多种乳腺癌细胞系表达降低,尤其是在乳腺癌细胞系MDA-MB231中表达量显著降低(P<0.000 1)。过表达miR-148a使MDA-MB231细胞的葡萄糖摄取量、乳酸生成量、细胞增殖指标均显著下降(P<0.01);而抑制miR-148a表达使MDA-MB231细胞葡萄糖摄取量、乳酸生成量、细胞增殖指标均显著上升(P<0.01)。通过TargetScan在线数据库预测得出,miR-148a与HK2基因3′非编码区(3′-untranslated region,3′-UTR)具有部分结合位点;而双荧光素酶报告实验发现miR-148a与野生型HK2基因的3′-UTR荧光素酶报告载体结合,不与突变型HK2基因的3′-UTR结合。Western免疫印迹检测结果表明,过表达miR-148a使MDA-MB231细胞中HK2蛋白表达量显著下降(P<0.000 1),而抑制miR-148a表达则促进HK2蛋白表达量显著上升(P<0.05)。基因回复实验显示,过表达HK2基因使MDA-MB231乳腺癌细胞的葡萄糖摄取量、乳酸生成量、细胞增殖指标显著上升(P<0.01);将过表达miR-148a载体与过表达HK2载体共转染MDA-MB231细胞,miR-148a逆转了HK2所致的葡萄糖摄取量增加和乳酸生成量上升,并抑制细胞增殖。因此,研究提示,miR-148a可通过靶向抑制HK2基因表达而抑制乳腺癌细胞MDA-MB231糖酵解代谢和细胞增殖。  相似文献   

8.
Glucose metabolism as assessed by (18)FDG PET imaging provides prognostic information in patients with pancreatic cancer but the implications of manipulating glucose metabolism for therapeutic purposes are unknown. Based on previous results with other cancer cell types, we hypothesized that inhibition of glucose metabolism in pancreatic cancer cells would cause cell killing via oxidative stress resulting from disruptions in thiol metabolism. 2-Deoxy-D-glucose (2DG), a chemical inhibitor of glucose metabolism, and glucose deprivation induced cytotoxicity in human pancreatic cancer cells in a time-and dose-dependent manner as well as causing significant increases in metabolic oxidative stress as measured by increased glutathione disulfide accumulation and NADP(+)/NADPH ratios. Simultaneous administration of the thiol antioxidant N-acetylcysteine protected pancreatic cancer cells against the c-ytotoxic effects of 2DG as well as reversing 2DG-induced glutathione disulfide accumulation and augmenting intracellular cysteine pools. In nude mice with heterotopic pancreatic tumors, the combination of 2DG and ionizing radiation resulted in greater inhibition of tumor growth and increased survival, relative to either agent alone. These results support the hypothesis that inhibiting glucose metabolism causes cytotoxicity in human pancreatic cancer cells via metabolic oxidative stress and disruptions in thiol metabolism. These results also support the speculation that inhibitors of glucose metabolism can be used in combination with classical oxidative stress-inducing agents (such as ionizing radiation) to enhance therapeutic responses in pancreatic cancer.  相似文献   

9.
10.
PHLPP2 is a member of the PHLPP family of phosphatases, known to suppress cell growth by inhibiting proliferation or promoting apoptosis. Oncogenic kinases Akt, S6K, and PKC, and pro-apoptotic kinase Mst1, have been recognized as functional targets of the PHLPP family. However, we observed that, in T-leukemia cells subjected to metabolic stress from glucose limitation, PHLPP2 specifically targets the energy-sensing AMP-activated protein kinase, pAMPK, rather than Akt or S6K. PHLPP2 dephosphorylates pAMPK in several other human cancer cells as well. PHLPP2 and pAMPK interact with each other, and the pleckstrin homology (PH) domain on PHLPP2 is required for their interaction, for dephosphorylating and inactivating AMPK, and for the apoptotic response of the leukemia cells to glucose limitation. Silencing PHLPP2 protein expression prolongs the survival of leukemia cells subjected to severe glucose limitation by promoting a switch to AMPK-mediated fatty acid oxidation for energy generation. Thus, this study reveals a novel role for PHLPP2 in suppressing a survival response mediated through AMPK signaling. Given the multiple ways in which PHLPP phosphatases act to oppose survival signaling in cancers and the pivotal role played by AMPK in redox homeostasis via glucose and fatty acid metabolism, the revelation that AMPK is a target of PHLPP2 could lead to better therapeutics directed both at cancer and at metabolic diseases.Subject terms: Cancer metabolism, Stress signalling  相似文献   

11.
12.
Acetyl-CoA, as an important molecule, not only participates in multiple intracellular metabolic reactions, but also affects the post-translational modification of proteins, playing a key role in the metabolic activity and epigenetic inheritance of cells. Cancer cells require extensive lipid metabolism to fuel for their growth, while also require histone acetylation modifications to increase the expression of cancer-promoting genes. As a raw material for de novo lipid synthesis and histone acetylation, acetyl-CoA has a major impact on lipid metabolism and histone acetylation in cancer. More importantly, in cancer, acetyl-CoA connects lipid metabolism with histone acetylation, forming a more complex regulatory mechanism that influences cancer growth, proliferation, metastasis.  相似文献   

13.
Cancer cells that escape induction therapy are a major cause of relapse. Understanding metabolic alterations associated with drug resistance opens up unexplored opportunities for the development of new therapeutic strategies. Here, we applied a broad spectrum of technologies including RNA sequencing, global untargeted metabolomics, and stable isotope labeling mass spectrometry to identify metabolic changes in P-glycoprotein overexpressing T-cell acute lymphoblastic leukemia (ALL) cells, which escaped a therapeutically relevant daunorubicin treatment. We show that compared with sensitive ALL cells, resistant leukemia cells possess a fundamentally rewired central metabolism characterized by reduced dependence on glutamine despite a lack of expression of glutamate-ammonia ligase (GLUL), a higher demand for glucose and an altered rate of fatty acid β-oxidation, accompanied by a decreased pantothenic acid uptake capacity. We experimentally validate our findings by selectively targeting components of this metabolic switch, using approved drugs and starvation approaches followed by cell viability analyses in both the ALL cells and in an acute myeloid leukemia (AML) sensitive/resistant cell line pair. We demonstrate how comparative metabolomics and RNA expression profiling of drug-sensitive and -resistant cells expose targetable metabolic changes and potential resistance markers. Our results show that drug resistance is associated with significant metabolic costs in cancer cells, which could be exploited using new therapeutic strategies.  相似文献   

14.
Metformin treatment has been associated with a decrease in breast cancer risk and improved survival. Metformin induces complex cellular changes, resulting in decreased tumor cell proliferation, reduction of stem cells, and apoptosis. Using a carcinogen-induced rodent model of mammary tumorigenesis, we recently demonstrated that overfeeding in obese animals is associated with a 50% increase in tumor glucose uptake, increased proliferation, and tumor cell reprogramming to an “aggressive” metabolic state. Metformin significantly inhibited these pro-tumorigenic effects. We hypothesized that a dynamic relationship exists between chronic energy excess (glucose by dose) and metformin efficacy/action.

Media glucose concentrations above 5 mmol/L was associated with significant increase in breast cancer cell proliferation, clonogenicity, motility, upregulation/activation of pro-oncogenic signaling, and reduction in apoptosis. These effects were most significant in triple-negative breast cancer (TNBC) cell lines. High-glucose conditions (10 mmol/L or above) significantly abrogated the effects of metformin. Mechanisms of metformin action at normal vs. high glucose overlapped but were not identical; for example, metformin reduced IGF-1R expression in both the HER2+ SK-BR-3 and TNBC MDA-MB-468 cell lines more significantly at 5, as compared with 10 mmol/L glucose. Significant changes in gene profiles related to apoptosis, cellular processes, metabolic processes, and cell proliferation occurred with metformin treatment in cells grown at 5 mmol/L glucose, whereas under high-glucose conditions, metformin did not significantly increase apoptotic/cellular death genes. These data indicate that failure to maintain glucose homeostasis may promote a more aggressive breast cancer phenotype and alter metformin efficacy and mechanisms of action.  相似文献   

15.
16.
TRAIL, a putative anticancer cytokine, induces extrinsic cell death by activating the caspase cascade directly (Type I cells) via the death-inducing signaling complex (DISC) or indirectly (Type II cells) by caspase-8 cleavage of Bid and activation of the mitochondrial cell death pathway. Cancer cells are characterized by their dependence on aerobic glycolysis, which, although inefficient in terms of ATP production, facilitates tumor metabolism. Our studies show that TRAIL-induced cell death is significantly affected by the metabolic status of the cell. Inhibiting glycolysis with 2-deoxyglucose potentiates TRAIL-induced cell death, whereas glucose deprivation can paradoxically inhibit apoptosis. These conflicting responses to glycolysis inhibition are modulated by the balance between the Akt and AMPK pathways and their subsequent downstream regulation of mTORC1. This results in marked changes in protein translation, in which the equilibrium between anti- and pro-apoptotic Bcl-2 family member proteins is decided by their individual degradation rates. This regulates the mitochondrial cell death pathway and alters its sensitivity not only to TRAIL, but to ABT-737, a Bcl-2 inhibitor. Taken together, our studies show that the sensitivity of cancer cells to apoptosis can be modulated by targeting their unique metabolism in order to enhance sensitivity to apoptotic agents.  相似文献   

17.
TRAIL, a putative anticancer cytokine, induces extrinsic cell death by activating the caspase cascade directly (Type I cells) via the death-inducing signaling complex (DISC) or indirectly (Type II cells) by caspase-8 cleavage of Bid and activation of the mitochondrial cell death pathway. Cancer cells are characterized by their dependence on aerobic glycolysis, which, although inefficient in terms of ATP production, facilitates tumor metabolism. Our studies show that TRAIL-induced cell death is significantly affected by the metabolic status of the cell. Inhibiting glycolysis with 2-deoxyglucose potentiates TRAIL-induced cell death, whereas glucose deprivation can paradoxically inhibit apoptosis. These conflicting responses to glycolysis inhibition are modulated by the balance between the Akt and AMPK pathways and their subsequent downstream regulation of mTORC1. This results in marked changes in protein translation, in which the equilibrium between anti- and pro-apoptotic Bcl-2 family member proteins is decided by their individual degradation rates. This regulates the mitochondrial cell death pathway and alters its sensitivity not only to TRAIL, but to ABT-737, a Bcl-2 inhibitor. Taken together, our studies show that the sensitivity of cancer cells to apoptosis can be modulated by targeting their unique metabolism in order to enhance sensitivity to apoptotic agents.  相似文献   

18.
Channelling of glucose via glycogen, known as the glycogen shunt, may play an important role in the metabolism of brain tumours, especially in hypoxic conditions. We aimed to dissect the role of glycogen degradation in glioblastoma (GBM) response to ionising radiation (IR). Knockdown of the glycogen phosphorylase liver isoform (PYGL), but not the brain isoform (PYGB), decreased clonogenic growth and survival of GBM cell lines and sensitised them to IR doses of 10–12 Gy. Two to five days after IR exposure of PYGL knockdown GBM cells, mitotic catastrophy and a giant multinucleated cell morphology with senescence-like phenotype developed. The basal levels of the lysosomal enzyme alpha-acid glucosidase (GAA), essential for autolysosomal glycogen degradation, and the lipidated forms of gamma-aminobutyric acid receptor-associated protein-like (GABARAPL1 and GABARAPL2) increased in shPYGL U87MG cells, suggesting a compensatory mechanism of glycogen degradation. In response to IR, dysregulation of autophagy was shown by accumulation of the p62 and the lipidated form of GABARAPL1 and GABARAPL2 in shPYGL U87MG cells. IR increased the mitochondrial mass and the colocalisation of mitochondria with lysosomes in shPYGL cells, thereby indicating reduced mitophagy. These changes coincided with increased phosphorylation of AMP-activated protein kinase and acetyl-CoA carboxylase 2, slower ATP generation in response to glucose loading and progressive loss of oxidative phosphorylation. The resulting metabolic deficiencies affected the availability of ATP required for mitosis, resulting in the mitotic catastrophy observed in shPYGL cells following IR. PYGL mRNA and protein levels were higher in human GBM than in normal human brain tissues and high PYGL mRNA expression in GBM correlated with poor patient survival. In conclusion, we show a major new role for glycogen metabolism in GBM cancer. Inhibition of glycogen degradation sensitises GBM cells to high-dose IR indicating that PYGL is a potential novel target for the treatment of GBMs.Subject terms: Cancer metabolism, CNS cancer  相似文献   

19.
BackgroundAltered energy metabolism is a biochemical fingerprint of cancer cells, widely recognized as one of the “hallmarks of cancer”. Cancer cells show highly increased rates of glucose uptake and glycolysis, after which the resulting pyruvate is converted to lactate. The maintenance of this metabolic asset is warranted by lactate dehydrogenase A (LDH-A) and for this reason the development of novel LDH-targeted anticancer therapeutics is underway. However, possible interference in cancer cell metabolism could also arise from cAMP signaling pathway, which could be activated by either oncogenic induction or exogenously, as a result of microenvironment-derived stimuli, increasing cellular cAMP levels. This study aimed at evaluating the impact of activated cAMP signaling pathway on the efficacy of an LDH-targeted anticancer approach.MethodsWe exogenously activated cAMP signaling in MCF-7 human breast cancer cells and explored the metabolic interplay between LDH-A and cAMP pathway.ResultsIn cAMP-activated cells, we evidenced changes in energy metabolism which reduced their response to LDH inhibition. Interestingly, these experiments also highlighted a potential vulnerability state of treated cells.ConclusionscAMP-induced metabolic changes made MCF-7 cells a preferential target of a drug combination treatment which should not affect normal cell viability.General significancecAMP is a well-recognized second messenger of the pro-inflammatory cascade. The obtained results are relevant in consideration of the crucial role played by inflammation in normal breast cell transformation and in cancer progression. Furthermore, they corroborate the idea of exploiting the metabolic changes observed in cancer cells to obtain a therapeutic advantage.  相似文献   

20.
Chemoresistance is one of the major problems of colon cancer treatment. In tumors, glycolytic metabolism has been identified to promote cell proliferation and chemoresistance. However, the molecular mechanisms underlying glycolytic metabolism and chemoresistance in colon cancer remains enigmatic. Hence, this research was designed to explore the mechanism underlying the OLR1/c-MYC/SULT2B1 axis in the regulation of glycolytic metabolism, to affect colon cancer cell proliferation and chemoresistance. Colon cancer tissues and LoVo cells were attained, where OLR1, c-MYC, and SULT2B1 expression was detected by immunohistochemistry, RT-qPCR, and western blot analysis. Next, ectopic expression and knockdown assays were implemented in LoVo cells. Cell proliferation was detected by MTS assay and clone formation. Extracellular acidification, glucose uptake, lactate production, ATP/ADP ratio, and GLUT1 and LDHA expression were measured to evaluate glycolytic metabolism. Then, the transfected cells were treated with chemotherapeutic agents to assess drug resistance by MTS experiments and P-gp and SMAD4 expression by RT-qPCR. A nude mouse model of colon cancer transplantation was constructed for in vivo verification. The levels of OLR1, c-MYC, and SULT2B1 were upregulated in colon cancer tissues and cells. Mechanistically, OLR1 increased c-MYC expression to upregulate SULT2B1 in colon cancer cells. Moreover, knockdown of OLR1, c-MYC, or SULT2B1 weakened glycolytic metabolism, proliferation, and chemoresistance of colon cancer cells. In vivo experiments authenticated that OLR1 knockdown repressed the tumorigenesis and chemoresistance in nude mice by downregulating c-MYC and SULT2B1. Conclusively, knockdown of OLR1 might diminish SULT2B1 expression by downregulating c-MYC, thereby restraining glycolytic metabolism to inhibit colon cancer cell proliferation and chemoresistance.Subject terms: Cancer, Cancer therapy  相似文献   

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