The warburg effect and tumour cell survival in human GBMs

2007 ◽  
Vol 30 (4) ◽  
pp. 97 ◽  
Author(s):  
A Wolf ◽  
J Mukherjee ◽  
A Guha
Keyword(s):  
Cytochrome C ◽  
Cell Survival ◽  
Expression Profile ◽  
Tumour Cell ◽  
Warburg Effect ◽  
Glycolytic Enzymes ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
The Warburg Effect

Introduction: GBMs are resistant to apoptosis induced by the hypoxic microenvironment and standard therapies including radiation and chemotherapy. We postulate that the Warburg effect, a preferential glycolytic phenotype of tumor cells even under aerobic conditions, plays a role in these aberrant pro-survival signals. In this study we quantitatively examined the expression profile of hypoxia-related glycolytic genes within pathologically- and MRI-defined “centre” and “periphery” of GBMs. We hypothesize that expression of hypoxia-induced glycolytic genes, particularly hexokinase 2 (HK2), favours cell survival and modulates resistance to tumour cell apoptosis by inhibiting the intrinsic mitochondrial apoptotic pathway. Methods: GBM patients underwent conventional T1-weighted contrast-enhanced MRI and MR spectroscopy studies on a 3.0T GE scanner, prior to stereotactic sampling (formalin and frozen) from regions which were T1-Gad enhancing (“centre”) and T2-positive, T1-Gad negative (“periphery”). Real-time qRT-PCR was performed to quantify regional gene expression of glycolytic genes including HK2. In vitro functional studies were performed in U87 and U373 GBM cell lines grown in normoxic (21% pO2) and hypoxic (< 1%pO2) conditions, transfected with HK2 siRNA followed by measurement of cell proliferation (BrdU), apoptosis (activated caspase 3/7, TUNEL, cytochrome c release) and viability (MTS assay). Results: There exists a differential expression profile of glycolytic enzymes between the hypoxic center and relatively normoxic periphery of GBMs. Under hypoxic conditions, there is increased expression of HK2 at the mitochondrial membrane in GBM cells. In vitro HK2 knockdown led to decreased cell survival and increased apoptosis via the intrinsic mitochondrial pathway, as seen by increased mitochondrial release of cytochrome-C. Conclusions: Increased expression of HK2 in the centre of GBMs promotes cell survival and confers resistance to apoptosis, as confirmed by in vitro studies. In vivo intracranial xenograft studies with injection of HK2-shRNA are currently being performed. HK2 and possibly other glycolytic enzymes may provide a target for enhanced therapeutic responsiveness thereby improving prognosis of patients with GBMs.

scholarly journals Proton export drives the Warburg Effect

2021 ◽  
Author(s):  
Shonagh Russell ◽  
Liping Xu ◽  
Yoonseok Kam ◽  
Dominique Abrahams ◽  
Bryce Ordway ◽  
...  
Keyword(s):  
Warburg Effect ◽  
Cancer Metabolism ◽  
Aerobic Glycolysis ◽  
Lactate Production ◽  
Glycolytic Enzymes ◽  
Hek293 Cells ◽  
Driver Mutations ◽  
The Warburg Effect

Aggressive cancers commonly ferment glucose to lactic acid at high rates, even in the presence of oxygen. This is known as aerobic glycolysis, or the “Warburg Effect”. It is widely assumed that this is a consequence of the upregulation of glycolytic enzymes. Oncogenic drivers can increase the expression of most proteins in the glycolytic pathway, including the terminal step of exporting H+ equivalents from the cytoplasm. Proton exporters maintain an alkaline cytoplasmic pH, which can enhance all glycolytic enzyme activities, even in the absence of oncogene-related expression changes. Based on this observation, we hypothesized that increased uptake and fermentative metabolism of glucose could be driven by the expulsion of H+ equivalents from the cell. To test this hypothesis, we stably transfected lowly-glycolytic MCF-7, U2-OS, and glycolytic HEK293 cells to express proton exporting systems: either PMA1 (yeast H+-ATPase) or CAIX (carbonic anhydrase 9). The expression of either exporter in vitro enhanced aerobic glycolysis as measured by glucose consumption, lactate production, and extracellular acidification rate. This resulted in an increased intracellular pH, and metabolomic analyses indicated that this was associated with an increased flux of all glycolytic enzymes upstream of pyruvate kinase. These cells also demonstrated increased migratory and invasive phenotypes in vitro, and these were recapitulated in vivo by more aggressive behavior, whereby the acid-producing cells formed higher grade tumors with higher rates of metastases. Neutralizing tumor acidity with oral buffers reduced the metastatic burden. Therefore, cancer cells with increased H+ export increase intracellular alkalization, even without oncogenic driver mutations, and this is sufficient to alter cancer metabolism towards a Warburg phenotype.

scholarly journals Lysine 53 Acetylation of Cytochrome c in Prostate Cancer: Warburg Metabolism and Evasion of Apoptosis

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 802
Author(s):  
Viktoriia Bazylianska ◽  
Hasini A. Kalpage ◽  
Junmei Wan ◽  
Asmita Vaishnav ◽  
Gargi Mahapatra ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cytochrome C ◽  
Warburg Effect ◽  
Structural Features ◽  
Intrinsic Apoptosis ◽  
Metabolic Switch ◽  
Cancer Hallmarks ◽  
Dynamics Simulations ◽  
The Warburg Effect

Prostate cancer is the second leading cause of cancer-related death in men. Two classic cancer hallmarks are a metabolic switch from oxidative phosphorylation (OxPhos) to glycolysis, known as the Warburg effect, and resistance to cell death. Cytochrome c (Cytc) is at the intersection of both pathways, as it is essential for electron transport in mitochondrial respiration and a trigger of intrinsic apoptosis when released from the mitochondria. However, its functional role in cancer has never been studied. Our data show that Cytc is acetylated on lysine 53 in both androgen hormone-resistant and -sensitive human prostate cancer xenografts. To characterize the functional effects of K53 modification in vitro, K53 was mutated to acetylmimetic glutamine (K53Q), and to arginine (K53R) and isoleucine (K53I) as controls. Cytochrome c oxidase (COX) activity analyzed with purified Cytc variants showed reduced oxygen consumption with acetylmimetic Cytc compared to the non-acetylated Cytc (WT), supporting the Warburg effect. In contrast to WT, K53Q Cytc had significantly lower caspase-3 activity, suggesting that modification of Cytc K53 helps cancer cells evade apoptosis. Cardiolipin peroxidase activity, which is another proapoptotic function of the protein, was lower in acetylmimetic Cytc. Acetylmimetic Cytc also had a higher capacity to scavenge reactive oxygen species (ROS), another pro-survival feature. We discuss our experimental results in light of structural features of K53Q Cytc, which we crystallized at a resolution of 1.31 Å, together with molecular dynamics simulations. In conclusion, we propose that K53 acetylation of Cytc affects two hallmarks of cancer by regulating respiration and apoptosis in prostate cancer xenografts.

scholarly journals Gene Expression Profile of In Vitro Produced Bovine Blastocysts Exposed to Hyperglycemia During Early Cleavage Stages: Link with the Warburg Effect.

2011 ◽  
Vol 85 (Suppl_1) ◽  
pp. 81-81 ◽  
Author(s):  
Gael L.M. Cagnone ◽  
Isabelle Dufort ◽  
Christian Vigneault ◽  
Claude Robert ◽  
Marc-Andre Sirard
Keyword(s):  
Gene Expression ◽  
Gene Expression Profile ◽  
Expression Profile ◽  
Warburg Effect ◽  
Early Cleavage ◽  
Cleavage Stages ◽  
The Warburg Effect

In vitro and in vivo investigations of novel 1,4-napthoquinone sulphomethylene carbohydrate conjugates in prostate cancer.

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 104-104
Author(s):  
Tobias Busenbender ◽  
Sergey Dyshlovoy ◽  
Moritz Kaune ◽  
Lukas Boeckelmann ◽  
Tobias Lange ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Er Stress ◽  
Cancer Cells ◽  
Warburg Effect ◽  
Human Prostate ◽  
Human Prostate Cancer ◽  
Apoptotic Pathway ◽  
The Warburg Effect

104 Background: The Warburg effect describes the ability of cancer cells to consume larger amounts of glucose in comparison to normal tissue, due to the overexpression of insulin-independent glucose transporters (e.g. GLUT1). This effect can be used to enhance the selectivity and reduce side effects of cytotoxic anticancer molecules by its conjugation to sugar residues, thus, generating cytotoxic agents showing higher selectivity to cancer cells. In continuation of our research on anticancer natural 1,4-naphthoquinones we have investigated a large series of novel semi-synthetic molecules containing 1,4-naphthoquinones element conjugated with glucose molecule via -S-CH2- bond. Methods: We performed screening examinations for 35 novel synthetic molecules in human prostate cancer in vitro. The selected most active compounds were tested in several human prostate cancer cell lines harboring different levels of drug resistance, as well as in non-malignant cells to specify their selectivity. Compounds with the highest cytotoxicity and selectivity were further investigated. The mode of action was assessed including effects on apoptosis induction, oxidative stress, mitochondria, AR-signaling as well as glucose uptake and ER stress were assessed. In vivo dose finding and efficacy analyses were performed. Results: We identified two promising derivatives, showing IC50s at low micro- and nanomolar concentrations. Glucose depletion from the culture media led to increased cytotoxicity and cotreatment with a GLUT1-inhibitor showed an antagonistic effect, suggesting a concurrent uptake and therefore a Warburg effect targeting. The selected compounds exhibited most pronounced cytotoxic activity in DU145 cells as well as 22Rv1 cells. Non-malignant cells were generally less affected. The mode of action involves a loss of mitochondrial membrane potential, a release of cytochrome c and AIF into the cytosol and an upregulation of caspase-9, caspase-3 and cleaved PARP, as well as downregulation of Bcl-2 and Survivin, indicating that mitochondria are a major target, leading to the activation of the intrinsic apoptotic pathway. Early events in treated cells are ROS production and calcium release into the cytosol, a marker of ER-stress. Furthermore, downregulation of the AR and its signaling was observed on mRNA- and protein-level. In vivo experiments revealed antitumor activity in a 22Rv1-xenograft mouse model without severe side effects. Conclusions: In conclusion, we were able to identify two glucose-conjugated 1,4-naphthoquinones exhibiting potent in vitro and in vivoactivity and selectivity in human prostate cancer cells due to the Warburg effect targeting. Cytotoxic activity was exerted via initial ROS production and ER stress leading to mitochondrial damage and the induction of the intrinsic apoptotic pathway.

LPA protects intestinal epithelial cells from apoptosis by inhibiting the mitochondrial pathway

2003 ◽  
Vol 284 (5) ◽  
pp. G821-G829 ◽  
Author(s):  
Wenlin Deng ◽  
De-An Wang ◽  
Elvira Gosmanova ◽  
Leonard R. Johnson ◽  
Gabor Tigyi
Keyword(s):  
Epithelial Cells ◽  
Cytochrome C ◽  
Protein Expression ◽  
Caspase 3 ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Antiapoptotic Activity

We previously showed ( Gastroenterology 123: 206–216, 2002) that lysophosphatidic acid (LPA) protects and rescues rat intestinal epithelial cells (IEC-6) from apoptosis. Here, we provide evidence for the LPA-elicited inhibition of the mitochondrial apoptotic pathway leading to attenuation of caspase-3 activation. Pretreatment of IEC-6 cells with LPA inhibited campothecin-induced caspase-9 and caspase-3 activation and DNA fragmentation. A caspase-9 inhibitor peptide mimicked the LPA-elicited antiapoptotic activity. LPA elicited ERK1/ERK2 and PKB/Akt phosphorylation. The LPA-elicited antiapoptotic activity and inhibition of caspase-9 activity were abrogated by pertussis toxin, PD 98059, wortmannin, and LY 294002. LPA reduced cytochrome c release from mitochondria and prevented activation of caspase-9. LPA prevented translocation of Bax from cytosol to mitochondria and increased the expression of the antiapoptotic Bcl-2 mRNA and protein. LPA had no effect on Bcl-xl, Bad, and Bak mRNA or protein expression. These data indicate that LPA protects IEC-6 cells from camptothecin-induced apoptosis through Gi-coupled inhibition of caspase-3 activation mediated by the attenuation of caspase-9 activation due to diminished cytochrome c release, involving upregulation of Bcl-2 protein expression and prevention of Bax translocation.

Platycodon grandiflorum Induces Apoptosis in SKOV3 Human Ovarian Cancer Cells Through Mitochondrial-Dependent Pathway

2010 ◽  
Vol 38 (02) ◽  
pp. 373-386 ◽  
Author(s):  
Qin Hu ◽  
Ruile Pan ◽  
Liwei Wang ◽  
Bo Peng ◽  
Jingtian Tang ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cytochrome C ◽  
Cancer Cells ◽  
Caspase 3 ◽  
Ovarian Cancer Cells ◽  
Mitochondrial Cytochrome ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Platycodon Grandiflorum ◽  
Mitochondrial Cytochrome C

Platycodon grandiflorum (Jacq.) A. DC., a Chinese food and medicine, has been used as expectorant traditionally. The present study aimed to investigate the effect of Platycodon grandiflorum extract (PGE) on SKOV3 ovarian cancer cells. 3-(4,5- dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay was used to monitor cell numbers, Annexin-V/propidium iodide (PI) staining, RT-PCR and Western blot were used to examine cell apoptosis, caspases activation. Bcl-2 and Bax expressions and mitochondrial cytochrome c release. Our result showed that PGE-induced apoptosis was associated with activation of caspase-3, -8 and -9, down-regulation of Bcl-2, up-regulation of Bax and release of mitochondrial cytochrome c to cytosol. The data indicate that PGE may have anti-tumor effect mainly via caspase-3 and caspase-9 dependent apoptotic pathway.

Preclinical study of a PARP inhibitor in neuroblastoma.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 9570-9570
Author(s):  
Anissa Addioui ◽  
Assila Belounis ◽  
Sonia Cournoyer ◽  
Carine Nyalendo ◽  
Rose- Marie Brito ◽  
...  
Keyword(s):  
Cell Survival ◽  
Synergistic Effects ◽  
Parp Inhibitor ◽  
Chemotherapeutic Agents ◽  
Tumor Initiating Cells ◽  
Apoptotic Pathway ◽  
Western Blots ◽  
Optimal Drug ◽  
Parp 1

9570 Background: Neuroblastoma (NB) is the most common extracranial solid tumor of childhood. In spite of many therapeutic improvements, only 60% survive long term despite aggressive combinations of multi-agent chemotherapy. In previous studies, we have demonstrated that tumor initiating cells (TIC) expressing CD133 (CD133high) in NB are more resistant to chemotherapy. Moreover, these cells express higher levels of PARP-1, a central protein involved in DNA repair. PARP-1 expression is significantly lower in NB usually showing spontaneous regression than in standard NB, suggesting an implication of PARP-1 in NB progression. The objective of this study is to determine the efficacy in vitro of AG-014699 (AG), a PARP- inhibitor, used in monotherapy or in combination to cisplatine (CP) and doxorubicine (DR), classical chemotherapeutic agents used in NB treatment, on NB cell survival. Methods: Six NB cell lines (parental or CD133high purified by flow cytometry (FACS)) were treated with AG alone or in association to CP or DR. PARP-1 ELISA protein assay was used to determine the optimal drug concentration needed to inhibit the protein. Cell survival was measured by MTT test. Western Blots were done to evaluate any apoptotic or autophagic pathway modulations. Quantification of DNA damage in treated cell was done by immunofluorescence of H2A-X protein. Results: We showed that a 4µM concentration of AG is sufficient for PARP-1 inhibition. One third of celllines presented a sensitivity to AG when used in monotherapy with an IC50 lower than 5µM. However, AG demonstrated synergistic effects when associated to DR, decreasing the IC50 by half, although none is observed when combined to CP. Sentitivity of the TIC did not appear to be more important than the bulk cells. With increasing concentration of AG, our WB showed no increase in cleaved Caspase-3 suggesting no modulation of the apoptotic pathway. However, autophagy seemed to be upregulated confirmed by an increase in cleaved LC3 II protein. Double strand breaks increased 2.5 folds when 4µM AG is added to the IC50 of DR. Conclusions: AG used in combination at potentially therapeutic doses shows promising results in NB. These results will allow for the improvement of NB treatments by introducing a new therapeutic strategy.

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