Choline kinase in Cuscuta reflexa.
Ontology highlight
ABSTRACT:
SUBMITTER: Setty PN
PROVIDER: S-EPMC1178381 | biostudies-other | 1972 Jan
REPOSITORIES: biostudies-other
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Project description:Choline kinase catalyzes the phosphorylation of choline, the first step of phospholipid synthesis. Increased phosphorylation of choline is a hallmark characteristic of the malignant phenotype in a variety of neoplasms. However, in hypoxic cancer cells, choline phosphorylation is decreased. To understand the mechanism behind this altered metabolic state, we examined the expression and regulation of the major choline kinase isoform, choline kinase ? (ChK?), in hypoxic PC-3 human prostate cancer cells. Hypoxia decreased choline phosphorylation, choline kinase activity, and ChK? mRNA and protein levels. Promoter analysis studies revealed a region upstream of the ChK? gene bearing a conserved DNA consensus binding motif, hypoxia response element-7 (HRE7), at position -222 relative to +1 translation start site, for binding the hypoxia dependent master regulator transcription factor, hypoxia-inducible factor 1? (HIF-1?). Electrophoretic mobility shift competition/supershift assay and chromatin immunoprecipitation assay confirmed binding of HIF-1? to HRE7. A putative promoter of ChK? was isolated from PC-3 genomic DNA and cloned into a luciferase-based reporter vector system. In PC-3 cells, hypoxia decreased the expression of luciferase under the control of the ChK? promoter. Mutation of HRE7 abrogated this hypoxia effect, further demonstrating the involvement of HRE7 in hypoxia-sensitive regulation of ChK?. The results strongly suggest that transcriptional control of choline phosphorylation is largely mediated via HIF-1? binding to the newly identified HRE7.
| S-EPMC3243471 | biostudies-literature
Project description:Little is known about targeting the metabolome in non-cancer conditions. Choline kinase (ChoK?), an essential enzyme for phosphatidylcholine biosynthesis, is required for cell proliferation and has been implicated in cancer invasiveness. Aggressive behaviour of fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) led us to evaluate whether this metabolic pathway could play a role in RA FLS function and joint damage.Choline metabolic profile of FLS cells was determined by (1)H magnetic resonance spectroscopy ((1)HMRS) under conditions of ChoK? inhibition. FLS function was evaluated using the ChoK? inhibitor MN58b (IC??=4.2??M). For arthritis experiments, mice were injected with K/BxN sera. MN58b (3?mg/kg) was injected daily intraperitoneal beginning on day 0 or day 4 after serum administration.The enzyme is expressed in synovial tissue and in cultured RA FLS. Tumour necrosis factor (TNF) and platelet-derived growth factor (PDGF) stimulation increased ChoK? expression and levels of phosphocholine in FLS measured by Western Blot (WB) and metabolomic studies of choline-containing compounds in cultured RA FLS extracts respectively, suggesting activation of this pathway in RA synovial environment. A ChoK? inhibitor also suppressed the behaviour of cultured FLS, including cell migration and resistance to apoptosis, which might contribute to cartilage destruction in RA. In a passive K/BxN arthritis model, pharmacologic ChoK? inhibition significantly decreased arthritis in pretreatment protocols as well as in established disease.These data suggest that ChoK? inhibition could be an effective strategy in inflammatory arthritis. It also suggests that targeting the metabolome can be a new treatment strategy in non-cancer conditions.
| S-EPMC4382461 | biostudies-literature
Project description:Detection of the abnormal phosphatidylcholine (PtdCho) metabolism in EOC by analysis of magnetic resonance profile (MRS), showed a significant increase of PCho content in EOC cells as compared with non tumoral counterparts associated with activation of choline kinase (ChoK), the enzyme responsible for PCho production following choline phosphorylation in the PtdCho biosynthetic pathway (Kennedy’s pathway). The α-isoform of ChoK has an essential role in growth control and signal transduction and it has been implicated in the carcinogenic process. Aim of the study is the evaluation of the biological relevance of ChoK expression and activity to define its possible role as a non-invasively detectable EOC biomarker and druggable target. We specifically silenced ChoKα expression by transient RNA interference in two different EOC cell lines and evaluated the biological effects related to metabolic profiles, cell proliferation, cell cycle regulation and alteration of global gene expression to possibly identify new pathways implicated in altered choline metabolism. Following ChoKα silencing we observed a 70% reduction of mRNA and protein expression with a similar reduction in PCho accumulation as assessed by HMRS analysis. The ChoKα silencing was accompanied by 20% inhibition of cell growth and similar percentage of cells blocked in the G1-phase of cell cycle. No alteration in cell morphology and modulation of the main survival signaling pathways (PI3K and MAPK-related signaling) were observed. By gene expression analysis we found 476 differentially expressed genes (p< 0.01; FDR 25%) in silenced cells. By transcriptome analysis of CHKA silenced cells as compared to controls, among the most relevant co-repressed genes we found CyclinA, related to regulation of cell cycle progression, and cytokines genes (IL-6 and IL-8) related to inflammation and EOC aggressiveness. Acyl-CoA synthetase medium-chain family member 3 (ACSM3), phosphatidic acid phosphatase type 2 (PPAP2A) and Osteoprotegerin were among the most up-regulated genes. All co-modulated genes have been validated by RTqPCR also in independent biological replicates. Ingenuity System Pathways Analysis (IPA) identified a network of molecules most significantly affected by CHKA silencing whose main functions is related to cell morphology cellular assembly and organization, cellular function and maintenance. Also, the cellular functions predicted to be mostly affected by silencing were cellular movement and cell death that are expected to be respectively decreased and increased in silenced cells. a total of 12 samples were analyzed: Two EOC cell line SKOV3 and INTOV11 were transiently silenced with unrelated or CHKA-specific siRNA pool. Three independent experiment were run for each cell line.
2014-01-23 | E-GEOD-39943 | biostudies-arrayexpress
Project description:Detection of the abnormal phosphatidylcholine (PtdCho) metabolism in EOC by analysis of magnetic resonance profile (MRS), showed a significant increase of PCho content in EOC cells as compared with non tumoral counterparts associated with activation of choline kinase (ChoK), the enzyme responsible for PCho production following choline phosphorylation in the PtdCho biosynthetic pathway (Kennedy’s pathway). The α-isoform of ChoK has an essential role in growth control and signal transduction and it has been implicated in the carcinogenic process. Aim of the study is the evaluation of the biological relevance of ChoK expression and activity to define its possible role as a non-invasively detectable EOC biomarker and druggable target. We specifically silenced ChoKα expression by transient RNA interference in two different EOC cell lines and evaluated the biological effects related to metabolic profiles, cell proliferation, cell cycle regulation and alteration of global gene expression to possibly identify new pathways implicated in altered choline metabolism. Following ChoKα silencing we observed a 70% reduction of mRNA and protein expression with a similar reduction in PCho accumulation as assessed by HMRS analysis. The ChoKα silencing was accompanied by 20% inhibition of cell growth and similar percentage of cells blocked in the G1-phase of cell cycle. No alteration in cell morphology and modulation of the main survival signaling pathways (PI3K and MAPK-related signaling) were observed. By gene expression analysis we found 476 differentially expressed genes (p< 0.01; FDR 25%) in silenced cells. By transcriptome analysis of CHKA silenced cells as compared to controls, among the most relevant co-repressed genes we found CyclinA, related to regulation of cell cycle progression, and cytokines genes (IL-6 and IL-8) related to inflammation and EOC aggressiveness. Acyl-CoA synthetase medium-chain family member 3 (ACSM3), phosphatidic acid phosphatase type 2 (PPAP2A) and Osteoprotegerin were among the most up-regulated genes. All co-modulated genes have been validated by RTqPCR also in independent biological replicates. Ingenuity System Pathways Analysis (IPA) identified a network of molecules most significantly affected by CHKA silencing whose main functions is related to cell morphology cellular assembly and organization, cellular function and maintenance. Also, the cellular functions predicted to be mostly affected by silencing were cellular movement and cell death that are expected to be respectively decreased and increased in silenced cells.
2014-01-23 | GSE39943 | GEO
Project description:Cancer cells have distinct metabolomic profile. Metabolic enzymes regulate key oncogenic signaling pathways and have an essential role on tumor progression. Here, serum metabolomic analysis was performed in 45 patients with T-cell lymphoma (TCL) and 50 healthy volunteers. The results showed that dysregulation of choline metabolism occurred in TCL and was related to tumor cell overexpression of choline kinase-α (Chokα). In T-lymphoma cells, pharmacological and molecular silencing of Chokα significantly decreased Ras-GTP activity, AKT and ERK phosphorylation and MYC oncoprotein expression, leading to restoration of choline metabolites and induction of tumor cell apoptosis/necropotosis. In a T-lymphoma xenograft murine model, Chokα inhibitor CK37 remarkably retarded tumor growth, suppressed Ras-AKT/ERK signaling, increased lysophosphatidylcholine levels and induced in situ cell apoptosis/necropotosis. Collectively, as a regulatory gene of aberrant choline metabolism, Chokα possessed oncogenic activity and could be a potential therapeutic target in TCL, as well as other hematological malignancies with interrupted Ras signaling pathways.
| S-EPMC4382653 | biostudies-literature
Project description:Specific deletion of the tumor suppressor TRAF3 from B lymphocytes in mice leads to the prolonged survival of mature B cells and expanded B cell compartments in secondary lymphoid organs. In the current study, we investigated the metabolic basis of TRAF3-mediated regulation of B cell survival by employing metabolomic, lipidomic, and transcriptomic analyses. We compared the polar metabolites, lipids, and metabolic enzymes of resting splenic B cells purified from young adult B cell-specific Traf3 -/- and littermate control mice. We found that multiple metabolites, lipids, and enzymes regulated by TRAF3 in B cells are clustered in the choline metabolic pathway. Using stable isotope labeling, we demonstrated that phosphocholine and phosphatidylcholine biosynthesis was markedly elevated in Traf3 -/- mouse B cells and decreased in TRAF3-reconstituted human multiple myeloma cells. Furthermore, pharmacological inhibition of choline kinase α, an enzyme that catalyzes phosphocholine synthesis and was strikingly increased in Traf3 -/- B cells, substantially reversed the survival phenotype of Traf3 -/- B cells both in vitro and in vivo. Taken together, our results indicate that enhanced phosphocholine and phosphatidylcholine synthesis supports the prolonged survival of Traf3 -/- B lymphocytes. Our findings suggest that TRAF3-regulated choline metabolism has diagnostic and therapeutic value for B cell malignancies with TRAF3 deletions or relevant mutations.
| S-EPMC6946882 | biostudies-literature
Project description:The phosphoinositide 3-kinase (PI3K) pathway is a major target for cancer drug development. PI-103 is an isoform-selective class I PI3K and mammalian target of rapamycin inhibitor. The aims of this work were as follows: first, to use magnetic resonance spectroscopy (MRS) to identify and develop a robust pharmacodynamic (PD) biomarker for target inhibition and potentially tumor response following PI3K inhibition; second, to evaluate mechanisms underlying the MRS-detected changes. Treatment of human PTEN null PC3 prostate and PIK3CA mutant HCT116 colon carcinoma cells with PI-103 resulted in a concentration- and time-dependent decrease in phosphocholine (PC) and total choline (tCho) levels (P < 0.05) detected by phosphorus ((31)P)- and proton ((1)H)-MRS. In contrast, the cytotoxic microtubule inhibitor docetaxel increased glycerophosphocholine and tCho levels in PC3 cells. PI-103-induced MRS changes were associated with alterations in the protein expression levels of regulatory enzymes involved in lipid metabolism, including choline kinase alpha (ChoK(alpha)), fatty acid synthase (FAS), and phosphorylated ATP-citrate lyase (pACL). However, a strong correlation (r(2) = 0.9, P = 0.009) was found only between PC concentrations and ChoK(alpha) expression but not with FAS or pACL. This study identified inhibition of ChoK(alpha) as a major cause of the observed change in PC levels following PI-103 treatment. We also showed the capacity of (1)H-MRS, a clinically well-established technique with higher sensitivity and wider applicability compared with (31)P-MRS, to assess response to PI-103. Our results show that monitoring the effects of PI3K inhibitors by MRS may provide a noninvasive PD biomarker for PI3K inhibition and potentially of tumor response during early-stage clinical trials with PI3K inhibitors.
| S-EPMC2896552 | biostudies-literature
Project description:It is well established that lipid metabolism is drastically altered during tumor development and response to therapy. Choline kinase alpha (ChoKα) is a key mediator of these changes, as it represents the first committed step in the Kennedy pathway of phosphatidylcholine biosynthesis and ChoKα expression is upregulated in many human cancers. ChoKα activity is associated with drug resistant, metastatic, and malignant phenotypes, and represents a robust biomarker and therapeutic target in cancer. Effective ChoKα inhibitors have been developed and have recently entered clinical trials. ChoKα's clinical relevance was, until recently, attributed solely to its production of second messenger intermediates of phospholipid synthesis. The recent discovery of a non-catalytic scaffolding function of ChoKα may link growth receptor signaling to lipid biogenesis and requires a reinterpretation of the design and validation of ChoKα inhibitors. Advances in positron emission tomography, magnetic resonance spectroscopy, and optical imaging methods now allow for a comprehensive understanding of ChoKα expression and activity in vivo. We will review the current understanding of ChoKα metabolism, its role in tumor biology and the development and validation of targeted therapies and companion diagnostics for this important regulatory enzyme. This comes at a critical time as ChoKα-targeting programs receive more clinical interest.
| S-EPMC5360181 | biostudies-literature
Project description:BackgroundCholine kinase has three isoforms encoded by the genes Chka and Chkb. Inactivation of Chka in mice results in embryonic lethality, whereas Chkb(-/-) mice display neonatal forelimb bone deformations.MethodsTo understand the mechanisms underlying the bone deformations, we compared the biology and biochemistry of bone formation from embryonic to young adult wild-type (WT) and Chkb(-/-) mice.ResultsThe deformations are specific to the radius and ulna during the late embryonic stage. The radius and ulna of Chkb(-/-) mice display expanded hypertrophic zones, unorganized proliferative columns in their growth plates, and delayed formation of primary ossification centers. The differentiation of chondrocytes of Chkb(-/-) mice was impaired, as was chondrocyte proliferation and expression of matrix metalloproteinases 9 and 13. In chondrocytes from Chkb(-/-) mice, phosphatidylcholine was slightly lower than in WT mice whereas the amount of phosphocholine was decreased by approximately 75%. In addition, the radius and ulna from Chkb(-/-) mice contained fewer osteoclasts along the cartilage/bone interface.ConclusionsChkb has a critical role in the normal embryogenic formation of the radius and ulna in mice.General significanceOur data indicate that choline kinase beta plays an important role in endochondral bone formation by modulating growth plate physiology.
| S-EPMC4143985 | biostudies-literature
Project description:The process of neuronal differentiation is associated with neurite elongation and membrane biogenesis, and phosphatidylcholine (PtdCho) is the major membrane phospholipid in mammalian cells. During neuroblast differentiation, the transcription of two genes involved in PtdCho biosynthesis are stimulated: Chka gene for choline kinase (CK) alpha isoform and Pcyt1a gene for CTP:phosphocholine cytidylyltransferase (CCT) alpha isoform. Here we show that CK? is essential for neuronal differentiation. In addition, we demonstrated that KDM2B regulates CK? expression and, as a consequence, neuronal differentiation. This factor is up-regulated in the course of the neuroblasts proliferative and undifferentiated state and down-regulated during differentiation induced by retinoic acid (RA). During proliferation, KDM2B binds to the Box2 located in the Chka promoter repressing its transcription. Interestingly, KDM2B knockdown enhances the levels of CK? expression in neuroblast cells and induces neuronal differentiation even in the absence of RA. These results suggest that KDM2B is required for the appropriate regulation of CK? during neuronal differentiation and to the maintaining of the undifferentiated stage of neuroblast cells.
| S-EPMC6328129 | biostudies-literature