Another Form of Modified, Highly-Active 6-Phosphofructo-1-Kinase in Cancer Cells

Enhanced glycolytic flux is a hallmarks of cancer cells. Posttranslational modification of the key regulatory enzyme of glycolysis, 6-Phosphofructo-1- Kinase (Pfk1) might trigger metabolic flux deregulation. In the cancer cells the human 85 kDa muscle type nPfk-M enzyme can be proteolytically cleaved to form highly-active 47 kDa shorter fragments that retain activity but become resistant to feed-back inhibition. In several tumorigenic cell lines, no native 85 kDa liver type nPfk-L isoforms could be either found and only 70 kDa shorter fragments were detected by immune-blotting. To learn more about the cancer-specific modified sfPfk-L enzyme, the truncated human sfPfk-L gene encoding 70 kDa fragments was inserted into the pfk null yeast S.cerevisiae cell. The recombinant modified enzyme showed higher affinity toward the substrate fructose-6-phosphate, reduced sensitivity toward the citrate and ATP inhibition in respect to the recombinant native PFK-L enzyme. Partially purified cancer-specific sfPfk-L fragments lacking the C-portion of the enzyme showed some instability under the diluted conditions in the buffer in respect to the tetrameric native nPfk-L enzyme. Growth characteristics of the yeast transformant encoding short sfPfk-L enzymes were similar to those encoding shorter sfPfk-M enzymes. No growth of the transformant with the sfPfk-L gene was observed on glucose but it grew faster than the transformant with the native human nPfk-L enzyme in a narrow ecological niche with low maltose concentration and 10 mM of ethanol in the medium. Similar to modified 47 kDa sfPfk-M fragments, also the short 70 kDa nPfk- Lfragments might cause deregulation of the glycolytic flux in the yeast and in the cancer cells. In yeast, deregulated metabolic flux unbalances redox potential that results in reduced growth rate. However, the cancer cells beat the redox unbalance by rapid re-oxidation of redundant NADH that results in lactate formation while the growth rate remains high.

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Fine tuning the glycolytic flux ratio of EP-bifido pathway for mevalonate production by enhancing glucose-6-phosphate dehydrogenase (Zwf) and CRISPRi suppressing 6-phosphofructose kinase (PfkA) in Escherichia coli

Microbial Cell Factories ◽

10.1186/s12934-021-01526-1 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Ying Li ◽

He Xian ◽

Ya Xu ◽

Yuan Zhu ◽

Zhijie Sun ◽

...

Keyword(s):

Pentose Phosphate Pathway ◽

Conversion Rate ◽

Metabolic Flux ◽

Flux Ratio ◽

Reducing Power ◽

Pentose Phosphate ◽

Fine Tuning ◽

High Yield ◽

Glycolytic Flux ◽

Acetyl Coa

Abstract Background Natural glycolysis encounters the decarboxylation of glucose partial oxidation product pyruvate into acetyl-CoA, where one-third of the carbon is lost at CO2. We previously constructed a carbon saving pathway, EP-bifido pathway by combining Embden-Meyerhof-Parnas Pathway, Pentose Phosphate Pathway and “bifid shunt”, to generate high yield acetyl-CoA from glucose. However, the carbon conversion rate and reducing power of this pathway was not optimal, the flux ratio of EMP pathway and pentose phosphate pathway (PPP) needs to be precisely and dynamically adjusted to improve the production of mevalonate (MVA). Result Here, we finely tuned the glycolytic flux ratio in two ways. First, we enhanced PPP flux for NADPH supply by replacing the promoter of zwf on the genome with a set of different strength promoters. Compared with the previous EP-bifido strains, the zwf-modified strains showed obvious differences in NADPH, NADH, and ATP synthesis levels. Among them, strain BP10BF accumulated 11.2 g/L of MVA after 72 h of fermentation and the molar conversion rate from glucose reached 62.2%. Second, pfkA was finely down-regulated by the clustered regularly interspaced short palindromic repeats interference (CRISPRi) system. The MVA yield of the regulated strain BiB1F was 8.53 g/L, and the conversion rate from glucose reached 68.7%. Conclusion This is the highest MVA conversion rate reported in shaken flask fermentation. The CRISPRi and promoter fine-tuning provided an effective strategy for metabolic flux redistribution in many metabolic pathways and promotes the chemicals production.

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Multifunctional Role of Astrocyte Elevated Gene-1 (AEG-1) in Cancer: Focus on Drug Resistance

Cancers ◽

10.3390/cancers13081792 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1792

Author(s):

Debashri Manna ◽

Devanand Sarkar

Keyword(s):

Drug Resistance ◽

Cancer Cells ◽

Cancer Development ◽

Epigenetic Alterations ◽

Hallmarks Of Cancer ◽

Comprehensive Description ◽

Molecular Abnormalities ◽

Selective Pressures ◽

Resistance To Chemotherapy

Cancer development results from the acquisition of numerous genetic and epigenetic alterations in cancer cells themselves, as well as continuous changes in their microenvironment. The plasticity of cancer cells allows them to continuously adapt to selective pressures brought forth by exogenous environmental stresses, the internal milieu of the tumor and cancer treatment itself. Resistance to treatment, either inherent or acquired after the commencement of treatment, is a major obstacle an oncologist confronts in an endeavor to efficiently manage the disease. Resistance to chemotherapy, chemoresistance, is an important hallmark of aggressive cancers, and driver oncogene-induced signaling pathways and molecular abnormalities create the platform for chemoresistance. The oncogene Astrocyte elevated gene-1/Metadherin (AEG-1/MTDH) is overexpressed in a diverse array of cancers, and its overexpression promotes all the hallmarks of cancer, such as proliferation, invasion, metastasis, angiogenesis and chemoresistance. The present review provides a comprehensive description of the molecular mechanism by which AEG-1 promotes tumorigenesis, with a special emphasis on its ability to regulate chemoresistance.

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Cre-loxP-mediated bax gene activation reduces growth rate and increases sensitivity to chemotherapeutic agents in human gastric cancer cells

Cancer Gene Therapy ◽

10.1038/sj.cgt.7700181 ◽

2000 ◽

Vol 7 (6) ◽

pp. 885-892 ◽

Cited By ~ 11

Author(s):

Koga Komatsu ◽

Susumu Suzuki ◽

Tooru Shimosegawa ◽

Jun-ichi Miyazaki ◽

Takayoshi Toyota

Keyword(s):

Gastric Cancer ◽

Growth Rate ◽

Cancer Cells ◽

Gene Activation ◽

Chemotherapeutic Agents ◽

Human Gastric Cancer ◽

Gastric Cancer Cells ◽

Bax Gene

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Targeting UCP2 Suppresses the FAK Signaling and Progression of Human Head and Neck Cancer Cells

Clinical Oncology and Research ◽

10.31487/j.cor.2020.04.09 ◽

2020 ◽

pp. 1-8

Author(s):

Yunfeng Zhao ◽

Cherie Ann Nathan ◽

Chunjing Zhang ◽

Hongyan Du ◽

Manikandan Panchatcharam ◽

...

Keyword(s):

Head And Neck ◽

Cancer Cells ◽

Cancer Progression ◽

Uncoupling Protein ◽

Human Head ◽

Atp Production ◽

Normal Tissues ◽

Tumor Tissues ◽

Lactate Formation

Background: New adjuvant therapies for human head and neck (H&N) cancer to improve the quality of life of the patients are in great demand. Our early studies have demonstrated that uncoupling protein 2 (UCP2) is upregulated in the tumor tissues of H&N cancer compared to the adjacent normal tissues; however, the role of UCP2 in H&N cancer has not been studied. Objective: In this manuscript, we aim to examine whether UCP2 contributes to H&N cancer progression in vitro. Methods: We generated UCP2 stable knockdown H&N cancer cells and detected the effects of UCP2 inhibition on cell proliferation, migration, invasion, 3D spheroid formation, and the sensitivity to a chemodrug treatment. Results: Knockdown of UCP2 suppressed the progression of H&N cancer in vitro, which might be mediated via the following mechanism: 1) increased the G1 phase whereas decreased the S phase of the cell cycle, which could be mediated by suppression of the G1/S regulators including CDK4/6 and cyclin D1. 2) Decreased mitochondrial oxygen consumption, ATP production, and lactate formation, which is consistent with the downregulation of c-Myc. 3) FAK may serve as the upstream signaling molecule, and its action was mediated by Akt and ERK. Conclusions: Our studies first demonstrate that targeting UCP2 may suppress H&N cancer progression in vitro.

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Highly active copper(i) complexes of aroylthiourea ligands against cancer cells – synthetic and biological studies

New Journal of Chemistry ◽

10.1039/c8nj04246b ◽

2019 ◽

Vol 43 (7) ◽

pp. 3188-3198 ◽

Cited By ~ 9

Author(s):

Kumaramangalam Jeyalakshmi ◽

Jebiti Haribabu ◽

Chandrasekar Balachandran ◽

Eswaramoorthi Narmatha ◽

Nattamai S. P. Bhuvanesh ◽

...

Keyword(s):

Cancer Cells ◽

Biological Applications ◽

Highly Active ◽

Biological Studies ◽

Sulfur Donor

Copper(i) complexes containing sulfur donor monodentate aroylthiourea ligands have been synthesized and evaluated for their biological applications.

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DJ-1 Proteoforms in Breast Cancer Cells: The Escape of Metabolic Epigenetic Misregulation

Cells ◽

10.3390/cells9091968 ◽

2020 ◽

Vol 9 (9) ◽

pp. 1968

Author(s):

Domenica Scumaci ◽

Erika Olivo ◽

Claudia Vincenza Fiumara ◽

Marina La Chimia ◽

Maria Teresa De Angelis ◽

...

Keyword(s):

Breast Cancer ◽

Oxidative Stress ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Glycolytic Flux ◽

Proliferative Potential ◽

Moderate Increase ◽

Reactive Carbonyl Species ◽

Proteomic Approach ◽

Age Related

Enhanced glycolysis is a hallmark of breast cancer. In cancer cells, the high glycolytic flux induces carbonyl stress, a damaging condition in which the increase of reactive carbonyl species makes DNA, proteins, and lipids more susceptible to glycation. Together with glucose, methylglyoxal (MGO), a byproduct of glycolysis, is considered the main glycating agent. MGO is highly diffusible, enters the nucleus, and can react with easily accessible lysine- and arginine-rich tails of histones. Glycation adducts on histones undergo oxidization and further rearrange to form stable species known as advanced glycation end-products (AGEs). This modification alters nucleosomes stability and chromatin architecture deconstructing the histone code. Formation of AGEs has been associated with cancer, diabetes, and several age-related diseases. Recently, DJ-1, a cancer-associated protein that protects cells from oxidative stress, has been described as a deglycase enzyme. Although its role in cell survival results still controversial, in several human tumors, its expression, localization, oxidation, and phosphorylation were found altered. This work aimed to explore the molecular mechanism that triggers the peculiar cellular compartmentalization and the specific post-translational modifications (PTM) that, occurring in breast cancer cells, influences the DJ-1 dual role. Using a proteomic approach, we identified on DJ-1 a novel threonine phosphorylation (T125) that was found, by the in-silico tool scansite 4, as part of a putative Akt consensus. Notably, this threonine is in addition to histidine 126, a key residue involved in the formation of catalytic triade (glu18-Cys106-His126) inside the glioxalase active site of DJ. Interestingly, we found that pharmacological modulation of Akt pathway induces a functional tuning of DJ-1 proteoforms, as well as their shuttle from cytosol to nucleus, pointing out that pathway as critical in the development of DJ-1 pro-tumorigenic abilities. Deglycase activity of DJ-1 on histones proteins, investigated by coupling 2D tau gel with LC-MS/MS and 2D-TAU (Triton-Acid-Urea)-Western blot, was found correlated with its phosphorylation status that, in turn, depends from Akt activation. In normal conditions, DJ-1 acts as a redox-sensitive chaperone and as an oxidative stress sensor. In cancer cells, glycolytic rewiring, inducing increased reactive oxygen species (ROS) levels, enhances AGEs products. Alongside, the moderate increase of ROS enhances Akt signaling that induces DJ-1-phosphorylation. When phosphorylated DJ-1 increases its glyoxalase activity, the level of AGEs on histones decreases. Therefore, phospho-DJ-1 prevents glycation-induced histones misregulation and its Akt-related hyperactivity represents a way to preserve the epigenome landscape sustaining proliferation of cancer cells. Together, these results shed light on an interesting mechanism that cancer cells might execute to escape the metabolic induced epigenetic misregulation that otherwise could impair their malignant proliferative potential.

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ALT: A Multi-Faceted Phenomenon

Genes ◽

10.3390/genes11020133 ◽

2020 ◽

Vol 11 (2) ◽

pp. 133 ◽

Cited By ~ 4

Author(s):

Aurore Sommer ◽

Nicola J. Royle

Keyword(s):

Molecular Markers ◽

Cancer Cells ◽

Targeted Therapies ◽

Sequence Variation ◽

Telomere Maintenance ◽

Hallmarks Of Cancer ◽

Telomere Elongation ◽

Maintenance Mechanism ◽

Alternative Lengthening ◽

Made In

One of the hallmarks of cancer cells is their indefinite replicative potential, made possible by the activation of a telomere maintenance mechanism (TMM). The majority of cancers reactivate the reverse transcriptase, telomerase, to maintain their telomere length but a minority (10% to 15%) utilize an alternative lengthening of telomeres (ALT) pathway. Here, we review the phenotypes and molecular markers specific to ALT, and investigate the significance of telomere mutations and sequence variation in ALT cell lines. We also look at the recent advancements in understanding the different mechanisms behind ALT telomere elongation and finally, the progress made in identifying potential ALT-targeted therapies, including those already in use for the treatment of both hematological and solid tumors.

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Glucose Metabolism in Pancreatic Cancer

Cancers ◽

10.3390/cancers11101460 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1460 ◽

Cited By ~ 10

Author(s):

Liang Yan ◽

Priyank Raj ◽

Wantong Yao ◽

Haoqiang Ying

Keyword(s):

Pancreatic Cancer ◽

Glucose Metabolism ◽

Cancer Cells ◽

Redox Homeostasis ◽

Central Carbon Metabolism ◽

Ductal Adenocarcinoma ◽

Glycolytic Flux ◽

Pancreatic Cancer Cells ◽

Cellular Energetics ◽

Salvage Pathways

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal cancers, with a five-year survival rate of around 5% to 8%. To date, very few available drugs have been successfully used to treat PDAC due to the poor understanding of the tumor-specific features. One of the hallmarks of pancreatic cancer cells is the deregulated cellular energetics characterized by the “Warburg effect”. It has been known for decades that cancer cells have a dramatically increased glycolytic flux even in the presence of oxygen and normal mitochondrial function. Glycolytic flux is the central carbon metabolism process in all cells, which not only produces adenosine triphosphate (ATP) but also provides biomass for anabolic processes that support cell proliferation. Expression levels of glucose transporters and rate-limiting enzymes regulate the rate of glycolytic flux. Intermediates that branch out from glycolysis are responsible for redox homeostasis, glycosylation, and biosynthesis. Beyond enhanced glycolytic flux, pancreatic cancer cells activate nutrient salvage pathways, which includes autophagy and micropinocytosis, from which the generated sugars, amino acids, and fatty acids are used to buffer the stresses induced by nutrient deprivation. Further, PDAC is characterized by extensive metabolic crosstalk between tumor cells and cells in the tumor microenvironment (TME). In this review, we will give an overview on recent progresses made in understanding glucose metabolism-related deregulations in PDAC.

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