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Cell Metabolism Jun 2023Metabolic reprogramming plays a crucial role in the development of hepatocellular carcinoma (HCC). However, the key drivers of metabolic reprogramming underlying HCC...
Metabolic reprogramming plays a crucial role in the development of hepatocellular carcinoma (HCC). However, the key drivers of metabolic reprogramming underlying HCC progression remain unclear. Using a large-scale transcriptomic database and survival correlation screening, we identify thymidine kinase 1 (TK1) as a key driver. The progression of HCC is robustly mitigated by TK1 knockdown and significantly aggravated by its overexpression. Furthermore, TK1 promotes the oncogenic phenotypes of HCC not only through its enzymatic activity and production of deoxythymidine monophosphate (dTMP) but also by promoting glycolysis via binding with protein arginine methyltransferase 1 (PRMT1). Mechanistically, TK1 directly binds PRMT1 and stabilizes it by interrupting its interactions with tripartite-motif-containing 48 (TRIM48), which inhibits its ubiquitination-mediated degradation. Subsequently, we validate the therapeutic capacity of hepatic TK1 knockdown in a chemically induced HCC mouse model. Therefore, targeting both the enzyme-dependent and -independent activity of TK1 may be therapeutically promising for HCC treatment.
Topics: Animals; Mice; Carcinoma, Hepatocellular; Liver Neoplasms; Thymidine Kinase; Ubiquitination; Cell Line, Tumor
PubMed: 37071992
DOI: 10.1016/j.cmet.2023.03.017 -
Microbiological Sciences Dec 1985
Review
Topics: Amino Acid Sequence; Base Sequence; Binding Sites; Gene Expression Regulation; Genes; Genes, Viral; Genetic Vectors; Sequence Homology, Nucleic Acid; Thymidine Kinase; Viral Vaccines; Viruses
PubMed: 3939993
DOI: No ID Found -
Journal of Neuromuscular Diseases 2022Defects in the replication, maintenance, and repair of mitochondrial DNA (mtDNA) constitute a growing and genetically heterogeneous group of mitochondrial disorders.... (Review)
Review
Defects in the replication, maintenance, and repair of mitochondrial DNA (mtDNA) constitute a growing and genetically heterogeneous group of mitochondrial disorders. Multiple genes participate in these processes, including thymidine kinase 2 (TK2) encoding the mitochondrial matrix protein TK2, a critical component of the mitochondrial nucleotide salvage pathway. TK2 deficiency (TK2d) causes mtDNA depletion, multiple deletions, or both, which manifest predominantly as mitochondrial myopathy. A wide clinical spectrum phenotype includes a severe, rapidly progressive, early onset form (median survival: < 2 years); a less severe childhood-onset form; and a late-onset form with a variably slower rate of progression. Clinical presentation typically includes progressive weakness of limb, neck, facial, oropharyngeal, and respiratory muscle, whereas limb myopathy with ptosis, ophthalmoparesis, and respiratory involvement is more common in the late-onset form. Deoxynucleoside monophosphates and deoxynucleosides that can bypass the TK2 enzyme defect have been assessed in a mouse model, as well as under open-label compassionate use (expanded access) in TK2d patients, indicating clinical efficacy with a favorable side-effect profile. This treatment is currently undergoing testing in clinical trials intended to support approval in the US and European Union (EU). In the early expanded access program, growth differentiation factor 15 (GDF-15) appears to be a useful biomarker that correlates with therapeutic response. With the advent of a specific treatment and given the high morbidity and mortality associated with TK2d, clinicians need to know how to recognize and diagnose this disorder. Here, we summarize translational research about this rare condition emphasizing clinical aspects.
Topics: Animals; Child; DNA, Mitochondrial; Humans; Mice; Mitochondrial Myopathies; Muscular Diseases; Thymidine Kinase
PubMed: 35094997
DOI: 10.3233/JND-210786 -
Cancer Letters Mar 2012Thymidine kinases (TK) have a key function in the synthesis of DNA. Two isoenzymes have been characterized: TK1 is cell cycle-dependent and present in the cytoplasm... (Review)
Review
Thymidine kinases (TK) have a key function in the synthesis of DNA. Two isoenzymes have been characterized: TK1 is cell cycle-dependent and present in the cytoplasm whereas TK2--located in mitochondria--is cell cycle-independent. The diagnostic and prognostic role of TK1 has recently been investigated. TK1 might be helpful for screening and monitoring of human malignancies. TK1 may also serve as a prognostic factor for progression. Herein, we summarize the status of TK1 for cancer monitoring and point out its use as a proliferation marker. A comprehensive overview about the association of TK-1 with various entities is given.
Topics: Biomarkers, Tumor; Cell Cycle; Humans; Isoenzymes; Neoplasms; Prognosis; Thymidine Kinase
PubMed: 22068047
DOI: 10.1016/j.canlet.2011.10.025 -
Current Topics in Medicinal Chemistry 2005Mitochondrial thymidine kinase or TK-2 belongs to the family of mammalian deoxynucleoside kinases (dNKs) that catalyze the phosphorylation of deoxynucleosides to their... (Review)
Review
Mitochondrial thymidine kinase or TK-2 belongs to the family of mammalian deoxynucleoside kinases (dNKs) that catalyze the phosphorylation of deoxynucleosides to their corresponding deoxynucleoside monophosphates by gamma-phosphoryl transfer of ATP. These enzymes are instrumental in the activation of deoxynucleoside analogues with biological and therapeutic properties. Moreover, dNKs are fundamental to maintain dNTPs pools for DNA synthesis and repair. TK-2 has a mitochondrial localization and is the only thymidine kinase that is physiologically active in non-proliferating and resting cells. Several recent investigations point to an important role of TK-2 in the maintenance of mitochondrial dNTPs pools. Indeed, mutations in the gene encoding TK-2 have been associated with mitochondrial DNA (mtDNA) depletion that mostly affects skeletal muscle. Moreover, TK-2 has been suggested to be implicated in mitochondrial toxicity associated to prolonged treatments with nucleoside analogues (i.e AZT for the treatment of AIDS patients). In this scenario, TK-2 inhibitors could be a useful tool to further clarify both the physiological role of TK-2 in the maintenance of mitochondrial dNTP pools, and the possible contribution of TK-2 to the mitochondrial toxicity of pyrimidine nucleoside analogues. In the present article we review the most recent literature covering different aspects of TK-2 as well as published TK-2 inhibitors, with special emphasis on acyclic nucleoside analogues that have been described by our research groups and whose prototype compound is 1-[(Z)-4-(triphenylmethoxy)-2-butenyl]thymine.
Topics: Animals; DNA, Mitochondrial; Dideoxynucleosides; Enzyme Inhibitors; Humans; Mitochondria; Nucleosides; Structure-Activity Relationship; Thymidine Kinase
PubMed: 16305527
DOI: 10.2174/156802605774463097 -
Cells Jan 2022Cell therapies based on pluripotent stem cells (PSC), have opened new therapeutic strategies for neurodegenerative diseases. However, insufficiently differentiated PSC...
Cell therapies based on pluripotent stem cells (PSC), have opened new therapeutic strategies for neurodegenerative diseases. However, insufficiently differentiated PSC can lead to tumor formation. Ideally, safety switch therapies should selectively kill proliferative transplant cells while preserving post-mitotic neurons. In this study, we evaluated the potential of nucleoside analogs and thymidine kinase-based suicide genes. Among tested thymidine kinase variants, the humanized SR39 (SR39h) variant rendered cells most sensitive to suicide induction. Unexpectedly, post-mitotic neurons with ubiquitous SR39h expression were killed by ganciclovir, but were spared when SR39h was expressed under the control of the cell cycle-dependent Ki67 promoter. The efficacy of six different nucleoside analogs to induce cell death was then evaluated. Penciclovir (PCV) showed the most interesting properties with an efficiency comparable to ganciclovir (GCV), but low toxicity. We tested three nucleoside analogs in vivo: at concentrations of 40 mg/kg/day, PCV and GCV prevented tumor formation, while acyclovir (ACV) did not. In summary, SR39h under the control of a cell cycle-dependent promoter appears most efficient and selective as safety switch for neural transplants. In this setting, PCV and GCV are efficient inducers of cell death. Because of its low toxicity, PCV might become a preferred alternative to GCV.
Topics: Cell- and Tissue-Based Therapy; Ganciclovir; Humans; Neurons; Nucleosides; Thymidine Kinase
PubMed: 35159311
DOI: 10.3390/cells11030502 -
Current Pharmaceutical Design 2012Thymidine kinase 2 (TK2), encoded on chromosome 16q22 of the human genome, is a deoxynucleoside kinase (dNK) that catalyzes the phosphorylation of the pyrimidine... (Review)
Review
Thymidine kinase 2 (TK2), encoded on chromosome 16q22 of the human genome, is a deoxynucleoside kinase (dNK) that catalyzes the phosphorylation of the pyrimidine deoxynucleosides 2'-deoxythymidine (dThd), 2'-deoxyuridine (dUrd) and 2'- deoxycytidine (dCyd) to the corresponding deoxynucleoside 5'-monophosphate derivatives. In contrast to the S-phase-specific thymidine kinase 1 (TK1), TK2 is constitutively expressed in the mitochondria and plays an important role in providing dNTPs for the replication and maintenance of mitochondrial DNA (mtDNA). The severe mitochondrial DNA depletion syndrome (MDS) has been associated with mutations in TK2, resulting in mtDNA depletion, isolated skeletal myopathy, and death of the individual at an early stage of life. Some antiviral nucleoside analogs, such as 3'-azido-dThd (AZT) that is targeting the human immunodeficiency virus (HIV)-encoded reverse transcriptase, are substrates for TK2 and it has been proposed that the mitochondrial toxicity observed after prolonged treatment with such drugs could be due to their interaction with TK2. Therefore, the design of specific TK2 inhibitors may be useful to investigate the role of TK2 in the maintenance and homeostasis of mitochondrial dNTP pools and its contribution to the mitochondrial toxicity of several antiviral and anticancer drugs. Since 2000, several potent and selective TK2 inhibitors have been described. Besides bringing together previously reported inhibitors, special attention will be paid in this review to the new families of TK2 inhibitors more recently described, together with modeling studies and biological assays. Moreover, the last section will be focused on several recent investigations that suggest that depletion of mtDNA can take place both in tumorigenesis and during cancer treatment with certain nucleoside analogues.
Topics: Animals; Antineoplastic Agents; Antiviral Agents; DNA, Mitochondrial; Drug Design; Enzyme Inhibitors; Humans; Mitochondria; Neoplasms; Phosphorylation; Thymidine Kinase
PubMed: 22571666
DOI: 10.2174/138161212800672787 -
Nucleosides, Nucleotides & Nucleic Acids Jun 2010The central enzyme on the de novo pathway for synthesis of DNA precursors, the deoxyribonucleoside triphosphates, is ribonucleotide reductase (RNR). Deoxythymidine... (Review)
Review
The central enzyme on the de novo pathway for synthesis of DNA precursors, the deoxyribonucleoside triphosphates, is ribonucleotide reductase (RNR). Deoxythymidine triphosphate (dTTP) has a key role in control of RNR activity shifting the specificity from pyrimidine to purine nucleotide reduction. Apart from the complex de novo synthesis of dTTP through UDP reduction, dTTP is provided through salvage of thymidine catalyzed by the thymidine kinases, the cytosolic and cell cycle regulated TK1 and the mitochondrial and constitutively expressed TK2. The complex enzymatic regulation of TK1 and TK2 and the possible physiological significance of this regulation will be discussed.
Topics: Animals; Cytosol; Humans; Mitochondria; Thymidine Kinase
PubMed: 20544521
DOI: 10.1080/15257771003729591 -
BMC Veterinary Research Sep 2021Thymidine kinase 1 (TK1) catalyzes the initial phosphorylation of thymidine in the salvage pathway synthesis of dTTP, an essential building block of DNA. TK1 is a...
BACKGROUND
Thymidine kinase 1 (TK1) catalyzes the initial phosphorylation of thymidine in the salvage pathway synthesis of dTTP, an essential building block of DNA. TK1 is a cytosolic enzyme with its highest level during the S-phase of the cell cycle. In cancer cells TK1 is upregulated and excess TK1 is leaked into the blood. Therefore, serum TK1 has been used as biomarker for cancer diagnosis and prognosis in human medicine. Feline TK1 shows high sequence similarity to TK1 from other species. The aim of this study was to characterize feline TK1 and evaluate if serum TK1 can be used as a diagnostic biomarker.
RESULTS
Feline TK1 was cloned, expressed and affinity purified. The purified feline TK1 phosphorylated not only pyrimidine deoxyribonucleosides but also pyrimidine ribonucleosides and to some extent purine deoxynucleosides. A number of anticancer and antiviral nucleoside analogs also served as substrates with fairly high efficiency. ATP and dATP were the preferred phosphate donor. Serum TK1 activity in felines with malignant diseases was significantly higher than that in healthy individuals. ROC analysis revealed an area under the curve (AUC) of 0.98 with a sensitivity of 0.83 and a specificity of 0.95 for felines with lymphoma. Serum TK1 activity in felines with IBD or inflammatory disease was within the same range as healthy ones. Furthermore, in felines with lymphoma serum TK1 activity returned to normal levels in response to treatment.
CONCLUSION
Feline TK1 has high specific activity and a broader substrate specificity in comparison with TK1 from other species. Serum TK1 activity in felines with malignant diseases is significantly higher than that in normal felines and in felines with inflammatory diseases. These results suggest that serum TK1 may be a promising biomarker for the diagnosis and monitoring of malignant diseases and for the differential diagnosis of certain inflammatory disease.
Topics: Animals; Biomarkers; Cat Diseases; Cats; Inflammation; Neoplasms; Sensitivity and Specificity; Thymidine Kinase
PubMed: 34579716
DOI: 10.1186/s12917-021-03030-5 -
Veterinary and Comparative Oncology Mar 2011As cell proliferation is one of the hallmarks of cancer, various types of proliferation markers are used as important tools in diagnosis, prognosis, treatment... (Comparative Study)
Comparative Study Review
As cell proliferation is one of the hallmarks of cancer, various types of proliferation markers are used as important tools in diagnosis, prognosis, treatment decision-making and follow-up in clinical oncology. The S phase-specific protein thymidine kinase 1 (TK1) can be used in immunohistochemistry for RNA/protein expression in tissue specimens and for activity or protein/peptide levels in serum from patients. TK1 has been used mainly in haematologic malignancies in humans, but also found beneficial in canine malignancies. As the protein sequence homology is high between humans and dogs, findings in canine models will have a high comparative value in further human research as well. In the present review, we will focus on the recent results concerning TK1's S phase-correlated expression, increased serum levels of TK1 in patients with malignancies and the relevance for veterinary and comparative oncology. Finally, the benefit of recently developed specific anti-TK1 antibodies suitable for immunologic assay is discussed.
Topics: Animals; Biomarkers, Tumor; Cell Proliferation; Disease Models, Animal; Dog Diseases; Dogs; Hematologic Neoplasms; Humans; Neoplasms; S Phase; Thymidine Kinase
PubMed: 21303450
DOI: 10.1111/j.1476-5829.2010.00238.x