scholarly journals Increased mTOR activity and metabolic efficiency in mouse and human cells containing the African-centric tumor-predisposing p53 variant Pro47Ser

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Keerthana Gnanapradeepan ◽  
Julia I-Ju Leu ◽  
Subhasree Basu ◽  
Thibaut Barnoud ◽  
Madeline Good ◽  
...  
Keyword(s):  
Cancer Risk ◽  
Oxidative Metabolism ◽  
Redox State ◽  
African Descent ◽  
Human Cells ◽  
Metabolic Efficiency ◽  
Wild Type ◽  
Positive Regulator ◽  
Wild Type P53 ◽  
Mtor Activity

The Pro47Ser variant of p53 (S47) exists in African-descent populations and is associated with increased cancer risk in humans and mice. Due to impaired repression of the cystine importer Slc7a11, S47 cells show increased glutathione (GSH) accumulation compared to cells with wild -type p53. We show that mice containing the S47 variant display increased mTOR activity and oxidative metabolism, as well as larger size, improved metabolic efficiency, and signs of superior fitness. Mechanistically, we show that mTOR and its positive regulator Rheb display increased association in S47 cells; this is due to an altered redox state of GAPDH in S47 cells that inhibits its ability to bind and sequester Rheb. Compounds that decrease glutathione normalize GAPDH-Rheb complexes and mTOR activity in S47 cells. This study reveals a novel layer of regulation of mTOR by p53, and raises the possibility that this variant may have been selected for in early Africa.

scholarly journals Increased mTOR activity and metabolic efficiency in mouse and human cells containing the African-centric tumor-predisposing p53 variant Pro47Ser

2020 ◽  
Author(s):  
Keerthana Gnanapradeepan ◽  
Subhasree Basu ◽  
Thibaut Barnoud ◽  
Julia I-Ju Leu ◽  
Madeline Good ◽  
...  
Keyword(s):  
Complex Formation ◽  
Cancer Risk ◽  
Oxidative Metabolism ◽  
Genetic Variants ◽  
Redox State ◽  
Human Cells ◽  
Metabolic Efficiency ◽  
Wild Type ◽  
Altered Regulation ◽  
Mtor Activity

AbstractThe Pro47Ser variant of p53 exists in African-descent populations, and is associated with increased cancer risk in humans and mice. This variant, hereafter S47, shows altered regulation of the cystine importer Slc7a11, and S47 cells possess increased cysteine and glutathione (GSH) accumulation compared to cells with wild type p53. In this study we show that mice containing the S47 variant have increased mTOR activity, increased oxidative metabolism, larger size, and improved metabolic efficiency. Mechanistically, we show that there is increased association between mTOR and its positive regulator Rheb in S47 cells, due to altered redox state of GAPDH, which normally binds and sequesters Rheb. Compounds that decrease glutathione in S47 cells normalize GAPDH-Rheb complex formation and mTOR activity. The enhanced metabolic efficiency may have been selected for in early Africa, making the S47 variant one of a growing number of cancer-predisposing genetic variants that possesses other positive, potentially selectable attributes.

scholarly journals Author response: Increased mTOR activity and metabolic efficiency in mouse and human cells containing the African-centric tumor-predisposing p53 variant Pro47Ser

2020 ◽  
Author(s):  
Keerthana Gnanapradeepan ◽  
Julia I-Ju Leu ◽  
Subhasree Basu ◽  
Thibaut Barnoud ◽  
Madeline Good ◽  
...  
Keyword(s):  
Human Cells ◽  
Author Response ◽  
Metabolic Efficiency ◽  
Mtor Activity

Targeting MHC-linked wild type p53 with TCR mimic single chain diabody for cancer immunotherapy.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 2524-2524
Author(s):  
Suman Paul ◽  
Jacqueline Douglass ◽  
Annika Schaefer ◽  
Emily Han-Chung Hsiue ◽  
Alexander Pearlman ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Surface ◽  
Cancer Immunotherapy ◽  
Cell Killing ◽  
Human Cells ◽  
Wild Type ◽  
Single Chain ◽  
Nsg Mice ◽  
Wild Type P53

2524 Background: Increased tumor suppressor protein p53 expression is observed in a wide range of human cancers. As a result there is intense interest in targeting p53 for cancer therapy. Intracellular p53 is inaccessible to therapeutic antibodies that bind cell surface proteins. However, intracellular proteins including p53 are degraded into peptides that are presented on cell surface in association with HLA class I molecules. Thus p53 peptide-HLA (p53-HLA) complexes can be antibody targets. Methods: Using phage display we identified a novel anti-p53-HLA single chain variable fragment (scFv) clone-43 that recognizes a wild-type p53 10-mer epitope bound to HLA-A*2402. By coupling our clone-43 scFv with an anti-CD3 scFv, we generated a single chain diabody (scDb) designed to activate T-cells against p53-expressing target cells. Results: In-vitro co-culture of clone-43 scDb with donor human T-cells and p53 expressing SIG-M5 cancer cells results in SIG-M5 cell killing and concomitant T-cell interferon gamma (IFNγ) release. In contrast, similar co-culture with SIG-M5 p53-knock out (KO) cells showed no cell killing and minimal IFNγ release demonstrating specificity of clone-43 to p53 expressing cells. Additionally, in-vivo growth of p53 expressing SW480 cancer cell xenografts in NSG mice was completely terminated by clone-43 scDb injections. A major concern for wild-type p53 epitope targeting is potential on-target off-tumor effect on non-cancerous tissue. We observed significant in-vitro clone-43 scDb mediated killing of human HLA-A*24:02 peripheral blood mononuclear cells. To better evaluate effect of clone-43 scDb on non-neoplastic human cells, we engrafted HLA-A*24:02 human CD34+ hematopoietic stem cells into NSG mice to generate a humanized mouse model with circulating mature human CD45+ cells. Clone-43 scDb treatment resulted in selective depletion of circulating human cells while the same cells persisted in mice treated with unrelated control scDb. Conclusions: Our observation that immune targeting of wild-type p53 epitope results in significant off-tumor hematopoietic cell death is contrary to previously published reports and carries important implications for future anti-p53 antibody and vaccine design for cancer immunotherapy.

Human p53 Expressed in Baculovirus-Infected Sf9 Cells Displays a Two-Dimensional Isoform Pattern Identical to Wild-Type p53 from Human Cells

1996 ◽  
Vol 330 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Rachel M. Patterson ◽  
Chaoying He ◽  
James K. Selkirk ◽  
B.Alex Merrick
Keyword(s):  
Human Cells ◽  
Sf9 Cells ◽  
Two Dimensional ◽  
Wild Type ◽  
Wild Type P53

scholarly journals Common and reversible regulation of wild-type p53 function and of ribosomal biogenesis by protein kinases in human cells

Oncogene ◽  
2001 ◽  
Vol 20 (42) ◽  
pp. 5951-5963 ◽  
Author(s):  
Thér`se David-Pfeuty ◽  
Yolande Nouvian-Dooghe ◽  
Valentina Sirri ◽  
Pascal Roussel ◽  
Dani`le Hernandez-Verdun
Keyword(s):  
Protein Kinases ◽  
Human Cells ◽  
Ribosomal Biogenesis ◽  
Wild Type ◽  
Wild Type P53

scholarly journals Role ofp16INK4Ain Replicative Senescence and DNA Damage-Induced Premature Senescence in p53-Deficient Human Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Razmik Mirzayans ◽  
Bonnie Andrais ◽  
Gavin Hansen ◽  
David Murray
Keyword(s):  
Dna Damage ◽  
Ionizing Radiation ◽  
Replicative Senescence ◽  
Human Cancer ◽  
Human Cells ◽  
Premature Senescence ◽  
Wild Type ◽  
Regulatory Relationship ◽  
Human Cancer Cell Lines ◽  
Wild Type P53

Thep16INK4A(hereafter p16) tumor suppressor is encoded by theINK4A/ARFlocus which is among the most commonly dysregulated sequences in human cancer. By inhibiting cyclin-dependent kinases, p16 activates the G1-S checkpoint, and this response is often considered to be critical for establishing a senescence-like growth arrest. Not all studies support a universal role for p16 in senescence. Single-cell analysis of noncancerous human fibroblast cultures undergoing senescence as a function of culture age (replicative senescence) has revealed that p16 is not expressed in the majority (>90%) of cells that exhibit features of senescence (e.g., flattened and enlarged morphology coupled with senescence-associatedβ-galactosidase expression), ruling out a requirement for p16 in this process. In addition, ionizing radiation triggers premature senescence in human cancer cell lines that do not express p16. These observations are made with cells that express wild-type p53, a key mediator of the DNA damage response. In this paper, we examine the growing evidence suggesting a negative regulatory relationship between p16 and p53 and discuss recent reports that implicate a role for p16 in replicative senescence and ionizing radiation-induced premature senescence in human cells that lack wild-type p53 function.

168 Post-radiation exit from G2 is related to endogenous RAF-1 protein levels in human cells expressing wild-type p53

1996 ◽  
Vol 36 (1) ◽  
pp. 242
Author(s):  
Hilmar Warenius ◽  
Tracy Gorman ◽  
Matthew Jones ◽  
Mark Jones ◽  
Christopher Thompson ◽  
...  
Keyword(s):  
Human Cells ◽  
Wild Type ◽  
Protein Levels ◽  
Post Radiation ◽  
Wild Type P53

Arabidopsis 4-COUMAROYL-COA LIGASE 8 contributes to the biosynthesis of the benzenoid ring of coenzyme Q in peroxisomes

2019 ◽  
Vol 476 (22) ◽  
pp. 3521-3532
Author(s):  
Eric Soubeyrand ◽  
Megan Kelly ◽  
Shea A. Keene ◽  
Ann C. Bernert ◽  
Scott Latimer ◽  
...  
Keyword(s):  
Oxidative Metabolism ◽  
Time Course ◽  
Reverse Genetics ◽  
De Novo ◽  
Coenzyme Q ◽  
Control Level ◽  
Wild Type ◽  
Fluorescent Reporters ◽  
Coa Ligase ◽  
Peroxisomal Targeting

Plants have evolved the ability to derive the benzenoid moiety of the respiratory cofactor and antioxidant, ubiquinone (coenzyme Q), either from the β-oxidative metabolism of p-coumarate or from the peroxidative cleavage of kaempferol. Here, isotopic feeding assays, gene co-expression analysis and reverse genetics identified Arabidopsis 4-COUMARATE-COA LIGASE 8 (4-CL8; At5g38120) as a contributor to the β-oxidation of p-coumarate for ubiquinone biosynthesis. The enzyme is part of the same clade (V) of acyl-activating enzymes than At4g19010, a p-coumarate CoA ligase known to play a central role in the conversion of p-coumarate into 4-hydroxybenzoate. A 4-cl8 T-DNA knockout displayed a 20% decrease in ubiquinone content compared with wild-type plants, while 4-CL8 overexpression boosted ubiquinone content up to 150% of the control level. Similarly, the isotopic enrichment of ubiquinone's ring was decreased by 28% in the 4-cl8 knockout as compared with wild-type controls when Phe-[Ring-13C6] was fed to the plants. This metabolic blockage could be bypassed via the exogenous supply of 4-hydroxybenzoate, the product of p-coumarate β-oxidation. Arabidopsis 4-CL8 displays a canonical peroxisomal targeting sequence type 1, and confocal microscopy experiments using fused fluorescent reporters demonstrated that this enzyme is imported into peroxisomes. Time course feeding assays using Phe-[Ring-13C6] in a series of Arabidopsis single and double knockouts blocked in the β-oxidative metabolism of p-coumarate (4-cl8; at4g19010; at4g19010 × 4-cl8), flavonol biosynthesis (flavanone-3-hydroxylase), or both (at4g19010 × flavanone-3-hydroxylase) indicated that continuous high light treatments (500 µE m−2 s−1; 24 h) markedly stimulated the de novo biosynthesis of ubiquinone independently of kaempferol catabolism.

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