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Leukemia & Lymphoma Apr 2013Clofarabine is a second-generation purine nucleoside analog that has been synthesized to overcome the limitations and incorporate the best qualities of fludarabine and... (Review)
Review
Clofarabine is a second-generation purine nucleoside analog that has been synthesized to overcome the limitations and incorporate the best qualities of fludarabine and cladribine. Clofarabine acts by inhibiting ribonucleotide reductase and DNA polymerase, thereby depleting the amount of intracellular deoxynucleoside triphosphates available for DNA replication. Compared to its precursors, clofarabine has an increased resistance to deamination and phosphorolysis, and hence better stability as well as higher affinity to deoxycytidine kinase (dCyd), the rate-limiting step in nucleoside phosphorylation. Since the initiation of the first phase I study of clofarabine in 1993 in patients with hematologic and solid malignancies, clofarabine has demonstrated single-agent antitumor activity in adult acute leukemia, including acute myeloid leukemia (AML). Due to its unique properties of biochemical modulation when used in combination with other chemotherapy drugs, mainly cytarabine, combination regimens containing clofarabine have been evaluated. A review of the English literature was performed that included original articles and related reviews from the MEDLINE (PubMed) database and from abstracts based on the publication of meeting materials. This review describes the development, pharmacology and clinical activity of clofarabine, as well as its emerging role in the treatment of adult patients with AML and myelodysplastic syndrome.
Topics: Adenine Nucleotides; Age Factors; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Arabinonucleosides; Clofarabine; Drug Evaluation, Preclinical; Humans; Leukemia, Myeloid, Acute
PubMed: 22957815
DOI: 10.3109/10428194.2012.726722 -
Cancer Drug Resistance (Alhambra,... 2020Gemcitabine is a cytidine analogue frequently used in the treatment of various cancers. However, the development of chemoresistance limits its effectiveness. Gemcitabine... (Review)
Review
Gemcitabine is a cytidine analogue frequently used in the treatment of various cancers. However, the development of chemoresistance limits its effectiveness. Gemcitabine resistance is regulated by various factors, including aberrant genetic and epigenetic controls, metabolism of gemcitabine, the microenvironment, epithelial-to-mesenchymal transition, and acquisition of cancer stem cell properties. In many situations, results using cell lines offer valuable lessons leading to the first steps of important findings. In this review, we mainly discuss the factors involved in gemcitabine metabolism in association with chemoresistance, including nucleoside transporters, deoxycytidine kinase, cytidine deaminase, and ATP-binding cassette transporters, and outline new perspectives for enhancing the efficacy of gemcitabine to overcome acquired chemoresistance.
PubMed: 35582220
DOI: 10.20517/cdr.2020.39 -
International Journal of Molecular... Aug 2023The aryl hydrocarbon receptor (AHR) is a transcription factor that is commonly upregulated in pancreatic ductal adenocarcinoma (PDAC). AHR hinders the shuttling of human...
The aryl hydrocarbon receptor (AHR) is a transcription factor that is commonly upregulated in pancreatic ductal adenocarcinoma (PDAC). AHR hinders the shuttling of human antigen R (ELAVL1) from the nucleus to the cytoplasm, where it stabilises its target messenger RNAs (mRNAs) and enhances protein expression. Among these target mRNAs are those induced by gemcitabine. Increased AHR expression leads to the sequestration of ELAVL1 in the nucleus, resulting in chemoresistance. This study aimed to investigate the interaction between AHR and ELAVL1 in the pathogenesis of PDAC in vitro. and genes were silenced by siRNA transfection. The RNA and protein were extracted for quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot (WB) analysis. Direct binding between the ELAVL1 protein and mRNA was examined through immunoprecipitation (IP) assay. Cell viability, clonogenicity, and migration assays were performed. Our study revealed that both AHR and ELAVL1 inter-regulate each other, while also having a role in cell proliferation, migration, and chemoresistance in PDAC cell lines. Notably, both proteins function through distinct mechanisms. The silencing of ELAVL1 disrupts the stability of its target mRNAs, resulting in the decreased expression of numerous cytoprotective proteins. In contrast, the silencing of diminishes cell migration and proliferation and enhances cell sensitivity to gemcitabine through the AHR-ELAVL1-deoxycytidine kinase (DCK) molecular pathway. In conclusion, AHR and ELAVL1 interaction can form a negative feedback loop. By inhibiting AHR expression, PDAC cells become more susceptible to gemcitabine through the ELAVL1-DCK pathway.
Topics: Humans; Carcinoma, Pancreatic Ductal; ELAV-Like Protein 1; Gemcitabine; Pancreas; Pancreatic Hormones; Pancreatic Neoplasms; Receptors, Aryl Hydrocarbon; RNA, Messenger; Deoxycytidine Kinase
PubMed: 37685961
DOI: 10.3390/ijms241713155 -
Genes Oct 2022Hepatocellular carcinoma (HCC) originates from the hepatocytes and accounts for 90% of liver cancer. The study intends to identify novel prognostic biomarkers for...
BACKGROUND
Hepatocellular carcinoma (HCC) originates from the hepatocytes and accounts for 90% of liver cancer. The study intends to identify novel prognostic biomarkers for predicting the prognosis of HCC patients based on TCGA and GSE14520 cohorts.
METHODS
Differential analysis was employed to obtain the DEGs (Differentially Expressed Genes) of the TCGA-LIHC-TPM cohort. The lasso regression analysis was applied to build the prognosis model through using the TCGA cohort as the training group and the GSE14520 cohort as the testing group. Next, based on the prognosis model, we performed the following analyses: the survival analysis, the independent prognosis analysis, the clinical feature analysis, the mutation analysis, the immune cell infiltration analysis, the tumor microenvironment analysis, and the drug sensitivity analysis. Finally, the survival time of HCC patients was predicted by constructing nomograms.
RESULTS
Through the lasso regression analysis, we obtained a prognosis model of ten genes including (baculoviral IAP repeat containing 5), (cyclin-dependent kinase 4), (deoxycytidine kinase), (heat shock protein family A member 4), (heat shock protein 90 α family class A member 1), (Proteasome 26S Subunit Ubiquitin Receptor, Non-ATPase 2), (interleukin 1 receptor antagonist), (placental growth factor), (secreted phosphoprotein 1), and (stanniocalcin 2). First, we found that the risk score is an independent prognosis factor and is related to the clinical features of HCC patients, covering AFP (α-fetoprotein) and stage. Second, we observed that the mutation was the most obvious mutation between the high-risk and low-risk groups. Third, we also discovered that the risk score is related to some immune cells, covering B cells, T cells, dendritic, macrophages, neutrophils, etc. Fourth, the high-risk group possesses a lower TIDE score, a higher expression of immune checkpoints, and higher ESTIMATE score. Finally, nomograms include the clinical features and risk signatures, displaying the clinical utility of the signature in the survival prediction of HCC patients.
CONCLUSIONS
Through the comprehensive analysis, we constructed an immune-related prognosis model to predict the survival of HCC patients. In addition to predicting the survival time of HCC patients, this model significantly correlates with the tumor microenvironment. Furthermore, we concluded that these ten immune-related genes (, , , , , , , , , and ) serve as novel targets for antitumor immunity. Therefore, this study plays a significant role in exploring the clinical application of immune-related genes.
Topics: Female; Humans; alpha-Fetoproteins; Biomarkers, Tumor; Carcinoma, Hepatocellular; Cyclin-Dependent Kinase 4; Deoxycytidine Kinase; Heat-Shock Proteins; Kaplan-Meier Estimate; Liver Neoplasms; Osteopontin; Placenta Growth Factor; Proteasome Endopeptidase Complex; Receptors, Interleukin-1; Tumor Suppressor Protein p53; Ubiquitins
PubMed: 36292719
DOI: 10.3390/genes13101834 -
Biochemical Pharmacology Feb 2020Deoxycytidine kinase (dCK) is an essential enzyme for production of nucleotides via the salvage pathway; DI-87 is a novel dCK inhibitor in preclinical development for...
BACKGROUND
Deoxycytidine kinase (dCK) is an essential enzyme for production of nucleotides via the salvage pathway; DI-87 is a novel dCK inhibitor in preclinical development for use in anticancer therapy. The current study utilizes PET imaging to evaluate PK-PD relationships and to determine optimal dosing of the drug.
METHODS
NSG mice bearing CEM tumors had plasma and tumor PK assessed using mass spectrometry following oral administration of DI-87. dCK inhibition was assessed after a single dose of oral DI-87 followed by a [F]CFA PET probe and PET imaging. Tumor growth inhibition was assessed by orally administering DI-87 with concurrent intraperitoneal thymidine.
RESULTS
DI-87 had an in vitro EC of 10.2 nM with low protein binding. Peak DI-87 concentrations were observed between 1-3 h and 3-9 h in plasma and tumor, respectively, with tumor concentrations less than one third of plasma. Full dCK inhibition, as evaluated by PET imaging, was observed as early as 3 h following 25 mg/kg dosing and was maintained for 12 h, with full recovery of enzyme activity after 36 h. When DI-87 was administered as repeated doses in combination with thymidine, full dCK inhibition was maintained at 12 h (25 mg/kg twice daily dose) and led to maximal tumor growth inhibition.
CONCLUSIONS
DI-87 is a promising new compound for use in combination therapy against tumors expressing dCK. Utilizing a [F]CFA PET probe targeting the pathway of interest allowed for efficient and accurate identification of the optimal dose for growth inhibition.
Topics: Animals; Antineoplastic Agents; Cell Line; Cell Proliferation; Deoxycytidine Kinase; Dose-Response Relationship, Drug; Drug Therapy, Combination; Gene Expression Regulation, Enzymologic; Humans; Male; Mice; Molecular Structure; Neoplasms, Experimental
PubMed: 31812677
DOI: 10.1016/j.bcp.2019.113742 -
Journal of Clinical Pathology Jul 2005Deoxycytidine kinase (dCK) is responsible for the activation of several clinically important deoxynucleoside analogues used for the treatment of haematological and solid...
BACKGROUND
Deoxycytidine kinase (dCK) is responsible for the activation of several clinically important deoxynucleoside analogues used for the treatment of haematological and solid malignancies.
AIM
To measure dCK expression in tumour cells from different origins.
METHOD
A rabbit antihuman dCK antibody was used for the immunocytochemical detection of dCK expression in three leukaemic cell lines (HL60, U937, and CCRF-CEM) and 97 patient samples (paediatric acute myeloid leukaemia (AML) and lymphoid leukaemia (ALL), retinoblastoma, paediatric brain tumours, and adult non-small cell lung cancer (NSCLC)).
RESULTS
CCRF-CEM, U937, and HL60 cells stained positively for dCK and the degree of expression correlated with dCK activity. dCK expression varied between tumour types and between individual patients within one tumour type. dCK was located predominantly in the cytoplasm. The staining intensity was scored as negative (0), low (1+), intermediate (2+), or high (3+). Expression of dCK was high in AML blasts. In contrast, brain tumour samples expressed low amounts of dCK. dCK staining ranged from low (1+) to high (3+) in ALL blasts, retinoblastoma, and NSCLC tissue samples. Staining was consistent (interobserver variability, 88%; kappa = 0.83) and specific. Western blotting detected the dCK protein appropriately at 30 kDa, without additional bands.
CONCLUSIONS
Immunocytochemistry is an effective and reliable method for determining the expression of dCK in patient samples and requires little tumour material. This method enables large scale screening of dCK expression in tumour samples.
Topics: Adult; Biomarkers, Tumor; Blotting, Western; Brain Neoplasms; Carcinoma, Non-Small-Cell Lung; Child; Cytoplasm; Deoxycytidine Kinase; Humans; Immunoenzyme Techniques; Leukemia; Lung Neoplasms; Neoplasms; Retinal Neoplasms; Retinoblastoma; Tumor Cells, Cultured
PubMed: 15976334
DOI: 10.1136/jcp.2004.023861 -
The Journal of Biological Chemistry Jun 1989The kinetic properties of 50,000-fold purified cultured human T lymphoblast (MOLT-4) deoxycytidine kinase were examined. The reaction velocity had an absolute...
The kinetic properties of 50,000-fold purified cultured human T lymphoblast (MOLT-4) deoxycytidine kinase were examined. The reaction velocity had an absolute requirement for magnesium. Maximal activity was observed at pH 6.5-7.0 with Mg:ATP for 1:1. High concentrations of free Mg2+ or free ATP were inhibitory. Double reciprocal plots of initial velocity studies yielded intersecting lines for both deoxycytidine and MgATP2-. dCMP was a competitive inhibitor with respect to deoxycytidine and ATP. ADP was a competitive inhibitor with respect to ATP and a mixed inhibitor with respect to deoxycytidine. dCTP, an important end product, is a very potent inhibitor and was a competitive inhibitor with respect to deoxycytidine and a non-competitive inhibitor with respect to ATP. TTP reversed dCTP inhibition. The data suggest that (a) MgATP2- is the true substrate of deoxycytidine kinase; (b) the kinetic mechanism of deoxycytidine kinase is consistent with rapid equilibrium random Bi Bi; (c) deoxycytidine kinase may be regulated by its product ADP and its end product dCTP as well as the availability of deoxycytidine. While many different nucleotides potently inhibit deoxycytidine kinase, their low intracellular concentrations make their regulatory role less important.
Topics: Adenosine Triphosphate; Cell Line; Deoxyadenosines; Deoxycytidine; Deoxycytidine Kinase; Deoxycytosine Nucleotides; Enzyme Activation; Humans; Kinetics; Magnesium; Phosphorylation; Phosphotransferases; T-Lymphocytes; Tumor Cells, Cultured
PubMed: 2542307
DOI: No ID Found -
The New Microbiologica Oct 2009It has been demonstrated that HIV infection may affect the levels of thymidine kinase (TK) and deoxycytidine kinase (dCK) in peripheral blood mononuclear cells from HIV...
It has been demonstrated that HIV infection may affect the levels of thymidine kinase (TK) and deoxycytidine kinase (dCK) in peripheral blood mononuclear cells from HIV infected adults. The aim of this study was to examine the effect of HIV infection and/or antiretroviral therapy on the activity of the above enzymes in HIV-infected children. The results showed that an inter-individual variability in TK and dCK activities does exist in both HIV infected and uninfected children. TK and dCK levels in PBMC from HIV infected and non infected children did not significantly differ. Furthermore, the therapeutic regimen, including zidovudine, does not seem to affect TK activity.
Topics: Adolescent; Adult; Anti-HIV Agents; Child; Child, Preschool; Deoxycytidine Kinase; Female; HIV Infections; HIV-1; Humans; Infant; Leukocytes, Mononuclear; Male; Thymidine Kinase; Zidovudine
PubMed: 20128449
DOI: No ID Found -
Cancer Science Feb 2004Nucleoside analogues which show antimetabolic activity in cells have been successfully used in the treatment of various tumors. Nucleosides such as... (Review)
Review
Nucleoside analogues which show antimetabolic activity in cells have been successfully used in the treatment of various tumors. Nucleosides such as 1-beta-D-arabinofuranosylcytosine (araC), 6-mercaptopurine, fludarabine and cladribine play an important role in the treatment of leukemias, while gemcitabine, 5-fluorouracil and its prodrugs are used extensively in the treatment of many types of solid tumors. All of these compounds are metabolized similarly to endogenous nucleosides and nucleotides. Active metabolites interfere with the de novo synthesis of nucleosides and nucleotides or inhibit the DNA chain elongation after being incorporated into the DNA strand as terminators. Furthermore, nucleoside antimetabolites incorporated into the DNA strand induce strand-breaks and finally cause apoptosis. Nucleoside antimetabolites target one or more specific enzyme(s). The mode of inhibitory action on the target enzyme is not always similar even among nucleoside antimetabolites which have the same nucleoside base, such as araC and gemcitabine. Although both nucleosides are phosphorylated by deoxycytidine kinase and are also good substrates of cytidine deaminase, only gemcitabine shows antitumor activity against solid tumors. This suggests that differences in the pharmacological activity of these nucleoside antimetabolites may reflect different modes of action on target molecules. The design, in vitro cytotoxicity, in vivo antitumor activity, metabolism and mechanism of action of sugar-modified cytosine nucleosides, such as (2'S)-2'-deoxy-2'-C-methylcytidine (SMDC), 1-(2-deoxy-2-methylene-beta-D-erythro-pentofuranosyl)cytosine (DMDC), 1-(2-C-cyano-2-deoxy-1-beta-D-arabino-pentofuranosyl)cytosine (CNDAC) and 1-(3-C-ethynyl-beta-D-ribo-pentofura-nosyl)cytosine (ECyd), developed by our groups, are discussed here.
Topics: Animals; Antimetabolites, Antineoplastic; Carbohydrates; Cytosine; Humans; Neoplasms; Pyrimidine Nucleosides
PubMed: 14965358
DOI: 10.1111/j.1349-7006.2004.tb03189.x -
The Journal of Biological Chemistry Sep 1980Three different deoxyribonucleoside kinases with specificities toward thymidine, deoxyguanosine, and deoxyadenosine/deoxycytidine, respectively, are identified in...
Three different deoxyribonucleoside kinases with specificities toward thymidine, deoxyguanosine, and deoxyadenosine/deoxycytidine, respectively, are identified in Bacillus subtilis. The deoxyadenosin/deoxycytidine kinase is purified 950-fold employing blue Sepharose CL-6B column chromatography. The two deoxyribonucleoside kinase activities copurify and are present in the same band after polyacrylamide gel electrophoresis. The molecular weight is determined by gel filtration to be 47,000. Cytidine, adenosine, arabinosylcytosine, and arabinosyladenine are substrates for the enzyme. The activities toward these substrates are less than 20% of the activities obtained with deoxyadenosin and deoxycytidine. The deoxycytidine and deoxyadenosine saturation curves are hyperbolic with Km values for both nucleosides around 5 microM. The maximal velocities for the two deoxyribonucleosides are nearly identical with GTP as phosphate donor. GTP is the best donor showing hyperbolic saturation curves and Km values around 150 microM depending on the deoxyribonucleoside concentration. dATP and dCTP are inhibitors when GTP is the phosphate donor. They may both act as phosphate donors themselves. A divalent metal ion is required, Mg2+ giving the highest activity. A spontaneous mutant, selected as resistant to 5-fluorodeoxycytidine, lacks both deoxycytidine and deoxyadenosine kinase activity, while it retains normal activities toward deoxyguanosine, deoxyuridine, and thymidine.
Topics: Bacillus subtilis; Cations, Divalent; Deoxyadenosines; Deoxycytidine Kinase; Kinetics; Magnesium; Phosphotransferases; Phosphotransferases (Alcohol Group Acceptor); Substrate Specificity
PubMed: 6251049
DOI: No ID Found