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Thymidylate Synthase Inhibitor
Thymidylate synthase inhibitors are chemical agents which inhibit the enzyme thymidylate synthase and have potential as an anticancer chemotherapy. This inhibition prevents the methylation of C5 of deoxyuridine monophosphate (dUMP) thereby inhibiting the synthesis of deoxythymidine monophosphate (dTMP). The downstream effect is promotion of cell death because cells would not be able to properly undergo DNA synthesis if they are lacking dTMP, a necessary precursor to dTTP. Five agents were in clinical trials in 2002: raltitrexed, pemetrexed, nolatrexed, ZD9331, and GS7904L. Examples include * Raltitrexed, used for colorectal cancer since 1998 * Fluorouracil, used for colorectal cancer * BGC 945 * OSI-7904L OSI-7904 is a noncompetitive liposomal thymidylate synthase inhibitor. OSI-7904 is a benzoquinazoline folate analog with antineoplastic activity. As a thymidylate synthase inhibitor, OSI-7904 noncompetitively binds to thymidylate synthase, resu ... References Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Inhibitor
An enzyme inhibitor is a molecule that binds to an enzyme and blocks its activity. Enzymes are proteins that speed up chemical reactions necessary for life, in which substrate molecules are converted into products. An enzyme facilitates a specific chemical reaction by binding the substrate to its active site, a specialized area on the enzyme that accelerates the most difficult step of the reaction. An enzyme inhibitor stops ("inhibits") this process, either by binding to the enzyme's active site (thus preventing the substrate itself from binding) or by binding to another site on the enzyme such that the enzyme's catalysis of the reaction is blocked. Enzyme inhibitors may bind reversibly or irreversibly. Irreversible inhibitors form a chemical bond with the enzyme such that the enzyme is inhibited until the chemical bond is broken. By contrast, reversible inhibitors bind non-covalently and may spontaneously leave the enzyme, allowing the enzyme to resume its function. Reve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymidylate Synthase
Thymidylate synthase (TS) () is an enzyme that catalyzes the conversion of deoxyuridine monophosphate (dUMP) to deoxythymidine monophosphate (dTMP). Thymidine is one of the nucleotides in DNA. With inhibition of TS, an imbalance of deoxynucleotides and increased levels of dUMP arise. Both cause DNA damage. Function The following reaction is catalyzed by thymidylate synthase: : 5,10-methylenetetrahydrofolate + dUMP \rightleftharpoons dihydrofolate + dTMP By means of reductive methylation, deoxyuridine monophosphate (dUMP) and N5,N10-methylene tetrahydrofolate are together used to form dTMP, yielding dihydrofolate as a secondary product. This provides the sole de novo pathway for production of dTMP and is the only enzyme in folate metabolism in which the 5,10-methylenetetrahydrofolate is oxidised during one-carbon transfer. The enzyme is essential for regulating the balanced supply of the 4 DNA precursors in normal DNA replication: defects in the enzyme activity affectin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemotherapy
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherapy may be given with a curative intent (which almost always involves combinations of drugs) or it may aim to prolong life or to reduce symptoms ( palliative chemotherapy). Chemotherapy is one of the major categories of the medical discipline specifically devoted to pharmacotherapy for cancer, which is called ''medical oncology''. The term ''chemotherapy'' has come to connote non-specific usage of intracellular poisons to inhibit mitosis (cell division) or induce DNA damage, which is why inhibition of DNA repair can augment chemotherapy. The connotation of the word chemotherapy excludes more selective agents that block extracellular signals (signal transduction). The development of therapies with specific molecular or genetic targets, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylation
In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These terms are commonly used in chemistry, biochemistry, soil science, and the biological sciences. In biological systems, methylation is catalyzed by enzymes; such methylation can be involved in modification of heavy metals, regulation of gene expression, regulation of protein function, and RNA processing. In vitro methylation of tissue samples is also one method for reducing certain histological staining artifacts. The reverse of methylation is demethylation. In biology In biological systems, methylation is accomplished by enzymes. Methylation can modify heavy metals, regulate gene expression, RNA processing and protein function. It has been recognized as a key process underlying epigenetics. Methanogenesis Methanogenesis, the process th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxythymidine Monophosphate
Thymidine monophosphate (TMP), also known as thymidylic acid (conjugate base thymidylate), deoxythymidine monophosphate (dTMP), or deoxythymidylic acid (conjugate base deoxythymidylate), is a nucleotide that is used as a monomer in DNA. It is an ester of phosphoric acid with the nucleoside thymidine. dTMP consists of a phosphate group, the pentose sugar deoxyribose, and the nucleobase thymine. Unlike the other deoxyribonucleotides, thymidine monophosphate often does not contain the "deoxy" prefix in its name; nevertheless, its symbol often includes a "d" ("dTMP"). ''Dorland’s Illustrated Medical Dictionary'' provides an explanation of the nomenclature variation at its entry for thymidine. As a substituent, it is called by the prefix thymidylyl-. See also * DNA * Nucleoside * Nucleotide * Oligonucleotide * RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raltitrexed
Raltitrexed (Thaltitrexed, Tomudex, TDX, ZD 1694) is an antimetabolite drug used in cancer chemotherapy. It is an inhibitor of thymidylate synthase, and is manufactured by AstraZeneca. Uses Used in treatment of colorectal cancer since 1998, it may also be used in the treatment of malignant mesothelioma. Raltitrexed is approved for use in Canada and some European countries, but is not approved by the US FDA. Mechanism of action Raltitrexed is chemically similar to folic acid and is in the class of chemotherapy drugs called folate antimetabolites, which inhibit one or more of three enzymes that use folate and derivatives as substrates: DHFR, GARFT and thymidylate synthase. Raltitrexed is fully active after polyglutamylation, which allows cellular retention of the drug. By inhibiting Thymidylate synthase (TS), thus formation of precursor pyrimidine nucleotides, raltitrexed prevents the formation of DNA and RNA, which are required for the growth and survival of both normal cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pemetrexed
Pemetrexed, sold under the brand name Alimta among others, is a chemotherapy medication for the treatment of pleural mesothelioma and non-small cell lung cancer (NSCLC).. It is available as a generic medication. Medical use In February 2004, the U.S. Food and Drug Administration (FDA) approved pemetrexed for treatment of malignant pleural mesothelioma, a type of tumor of the mesothelium, the thin layer of tissue that covers many of the internal organs, in combination with cisplatin for patients whose disease is either unresectable or who are not otherwise candidates for curative surgery. In September 2008, the FDA granted approval as a first-line treatment, in combination with cisplatin, against locally advanced and metastatic non-small cell lung cancer (NSCLC) in patients with non-squamous histology. Carboplatin Pemetrexed is also recommended in combination with carboplatin and pembrolizumab for the first-line treatment of advanced non-small cell lung cancer. However, the rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nolatrexed
Nolatrexed is a thymidylate synthase inhibitor Thymidylate synthase inhibitors are chemical agents which inhibit the enzyme thymidylate synthase and have potential as an anticancer chemotherapy. This inhibition prevents the methylation of C5 of deoxyuridine monophosphate (dUMP) thereby inhibiti .... References 4-Pyridyl compounds Thioethers Quinazolines Lactones Thymidylate synthase inhibitors {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raltitrexed
Raltitrexed (Thaltitrexed, Tomudex, TDX, ZD 1694) is an antimetabolite drug used in cancer chemotherapy. It is an inhibitor of thymidylate synthase, and is manufactured by AstraZeneca. Uses Used in treatment of colorectal cancer since 1998, it may also be used in the treatment of malignant mesothelioma. Raltitrexed is approved for use in Canada and some European countries, but is not approved by the US FDA. Mechanism of action Raltitrexed is chemically similar to folic acid and is in the class of chemotherapy drugs called folate antimetabolites, which inhibit one or more of three enzymes that use folate and derivatives as substrates: DHFR, GARFT and thymidylate synthase. Raltitrexed is fully active after polyglutamylation, which allows cellular retention of the drug. By inhibiting Thymidylate synthase (TS), thus formation of precursor pyrimidine nucleotides, raltitrexed prevents the formation of DNA and RNA, which are required for the growth and survival of both normal cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorouracil
Fluorouracil (5-FU), sold under the brand name Adrucil among others, is a cytotoxic chemotherapy medication used to treat cancer. By intravenous injection it is used for treatment of colorectal cancer, oesophageal cancer, stomach cancer, pancreatic cancer, breast cancer, and cervical cancer. As a cream it is used for actinic keratosis, basal cell carcinoma, and skin warts. Side effects of use by injection are common. They may include inflammation of the mouth, loss of appetite, low blood cell counts, hair loss, and inflammation of the skin. When used as a cream, irritation at the site of application usually occurs. Use of either form in pregnancy may harm the baby. Fluorouracil is in the antimetabolite and pyrimidine analog families of medications. How it works is not entirely clear, but it is believed to involve blocking the action of thymidylate synthase and thus stopping the production of DNA. Fluorouracil was patented in 1956 and came into medical use in 1962. It is on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
