Complete hamster CAD protein and the carbamylphosphate synthetase domain of CAD complement mammalian cell mutants defective in de novo pyrimidine biosynthesis

1992 ◽  
Vol 18 (4) ◽  
pp. 309-318 ◽  
Author(s):  
Lisa A. Musmanno ◽  
Robert S. Jamison ◽  
Richard S. Barnett ◽  
Edward Buford ◽  
Jeffrey N. Davidson
1987 ◽  
Vol 7 (5) ◽  
pp. 1961-1966
Author(s):  
G N Rao ◽  
E S Buford ◽  
J N Davidson

CAD codes for a trifunctional protein involved in the catalysis of the first three enzymatic activities in the de novo pyrimidine biosynthetic pathway, namely, carbamoyl-phosphate synthetase II (EC 6.3.5.5), aspartate transcarbamylase (EC 2.1.3.2), and dihydroorotase (EC 3.5.2.3). CAD regulation was studied in the human promyelocyte leukemic line HL-60 as it differentiated into monocytic or granulocytic lineages after induction by 12-O-tetradecanoylphorbol-13-acetate or trans-retinoic acid and dibutyryl cyclic AMP, respectively. Within 12 h of induction of HL-60 cells with either inducer, total cellular levels of CAD RNA essentially disappeared. On the other hand, no apparent decreases in beta-actin RNA levels were seen even 48 h after HL-60 cells were induced, as compared with untreated cells. With nuclear runoff assays, it was clearly shown that the inactivation of CAD gene expression during the induction of HL-60 cells with either inducer was at the transcriptional level. The nuclear runoff experiments also demonstrated that the CAD gene expression was shut down in less than 4 h after induction, well before morphological changes were observed in these cells. At the enzymatic level, the activity of aspartate transcarbamylase, one of the three enzymes encoded by the CAD gene, decreased by about half within 24 h of induction, suggesting a CAD protein half-life of 24 h in differentiating HL-60 cells. Nevertheless, this means that significant levels of aspartate transcarbamylase activity remained even after the cells have stopped proliferating. From the RNA data, it is clear that CAD gene expression is rapidly turned off as promyelocytes begin to terminally differentiate into macrophages and granulocytes. We suspect that the inactivation of the CAD gene in induced HL-60 cells is a consequence of the differentiating cells leaving the cell cycle and becoming nonproliferating.


2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Marianne Lucas-Hourani ◽  
Daniel Dauzonne ◽  
Hélène Munier-Lehmann ◽  
Samira Khiar ◽  
Sébastien Nisole ◽  
...  

ABSTRACT De novo pyrimidine biosynthesis is a key metabolic pathway involved in multiple biosynthetic processes. Here, we identified an original series of 3-(1H-indol-3-yl)-2,3-dihydro-4H-furo[3,2-c]chromen-4-one derivatives as a new class of pyrimidine biosynthesis inhibitors formed by two edge-fused polycyclic moieties. We show that identified compounds exhibit broad-spectrum antiviral activity and immunostimulatory properties, in line with recent reports linking de novo pyrimidine biosynthesis with innate defense mechanisms against viruses. Most importantly, we establish that pyrimidine deprivation can amplify the production of both type I and type III interferons by cells stimulated with retinoic acid-inducible gene 1 (RIG-I) ligands. Altogether, our results further expand the current panel of pyrimidine biosynthesis inhibitors and illustrate how the production of antiviral interferons is tightly coupled to this metabolic pathway. Functional and structural similarities between this new chemical series and dicoumarol, which was reported before to inhibit pyrimidine biosynthesis at the dihydroorotate dehydrogenase (DHODH) step, are discussed.


2018 ◽  
Vol 7 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Chao-Fu Yang ◽  
Balraj Gopula ◽  
Jian-Jong Liang ◽  
Jin-Kun Li ◽  
Si-Yu Chen ◽  
...  

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Raffaella Spina ◽  
Dillon M Voss ◽  
Xiaohua Yang ◽  
Jason W Sohn ◽  
Robert Vinkler ◽  
...  

Abstract Background Necrotic foci with surrounding hypoxic cellular pseudopalisades and microvascular hyperplasia are histological features found in glioblastoma (GBM). We have previously shown that monocarboxylate transporter 4 (MCT4) is highly expressed in necrotic/hypoxic regions in GBM and that increased levels of MCT4 are associated with worse clinical outcomes. Methods A combined transcriptomics and metabolomics analysis was performed to study the effects of MCT4 depletion in hypoxic GBM neurospheres. Stable and inducible MCT4-depletion systems were used to evaluate the effects of and underlining mechanisms associated with MCT4 depletion in vitro and in vivo, alone and in combination with radiation. Results This study establishes that conditional depletion of MCT4 profoundly impairs self-renewal and reduces the frequency and tumorigenicity of aggressive, therapy-resistant, glioblastoma stem cells. Mechanistically, we observed that MCT4 depletion induces anaplerotic glutaminolysis and abrogates de novo pyrimidine biosynthesis. The latter results in a dramatic increase in DNA damage and apoptotic cell death, phenotypes that were readily rescued by pyrimidine nucleosides supplementation. Consequently, we found that MCT4 depletion promoted a significant prolongation of survival of animals bearing established orthotopic xenografts, an effect that was extended by adjuvant treatment with focused radiation. Conclusions Our findings establish a novel role for MCT4 as a critical regulator of cellular deoxyribonucleotide levels and provide a new therapeutic direction related to MCT4 depletion in GBM.


FEBS Letters ◽  
1981 ◽  
Vol 128 (1) ◽  
pp. 27-29 ◽  
Author(s):  
David J. Hammond ◽  
Winston E. Gutteridge ◽  
Fred R. Opperdoes

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