An antimetabolite is a chemical that inhibits the use of metabolites, which are other chemicals that are part of normal metabolism. Such substances are often similar in structure to the metabolites they mix, such as antifolates that interfere with the use of folic acid. The presence of antimetabolites can have toxic effects on cells, such as stopping cell growth and cell division, so this compound is used as chemotherapy for cancer.
Video Antimetabolite
Function
Cancer treatment
Antimetabolites can be used in the treatment of cancer, because they interfere with the production of DNA and therefore cell division and tumor growth. Because cancer cells spend more time dividing than other cells, inhibiting cell division damages tumor cells more than other cells. Antimetabolite drugs are commonly used to treat leukemia, breast, ovarian, and gastrointestinal cancers, as well as other types of cancer. In the Anatomical Chemical Classification System, antimetabolite cancer drugs are classified under L01B.
Antimetabolites generally damage DNA replication machines, either by chemically altered nucleotides or by depleting the supplies of deoxynucleotides required for DNA replication and cell proliferation.
Contoh obat antimetabolit kanker termasuk, tetapi tidak terbatas pada yang berikut:
- 5-Fluorourasil (5-FU)
- 6-Mercaptopurine (6-MP)
- Capecitabine (Xeloda®)
- Cytarabine (Ara-C®)
- Floxuridine
- Fludarabine
- Gemcitabine (Gemzar®)
- Hidroksikarbamid
- Methotrexate
- Pemetrexed (Alimta®)
Anti-metabolites masquerade as purines (azathioprine, mercaptopurine) or pyrimidine, chemicals that become DNA-building blocks. They prevent these substances from being put into DNA during the S phase (from the cell cycle), stopping normal development and cell division. Anti-metabolites also affect RNA synthesis. However, since thymidine is used in DNA but not in RNA (where uracil is used instead), inhibition of thymidine synthesis through thymidylate synthase selectively inhibits DNA synthesis over RNA synthesis.
Because of their efficiency, these drugs are the most widely used cytostatics. Competition to bind enzyme sites that participate in important biosynthesis processes and incorporation of these biomolecules into nucleic acids, inhibits normal tumor cell function and trigger apoptosis, or cell death processes. Because of this work, most antimetabolites have a high specificity of cell cycle and can target the capture of DNA replication of cancer cells.
Antibiotics
Antimetabolites may also be antibiotics, such as sulfanilamide drugs, which inhibit the synthesis of dihydrofolate in bacteria by competing with para-aminobenzoic acid (PABA). PABA is needed in enzymatic reactions that produce folic acid, which acts as a coenzyme in purine and pyrimidine synthesis, the building block of DNA. Mammals do not synthesize their own folic acid so that they are not affected by the PABA inhibitor, which selectively kills bacteria. Sulfanilamide drugs are not like antibiotics used to treat infections. Instead, they work by converting DNA inside cancer cells so that they do not grow and multiply. Antibium antibiotics are a class of antimetabolite drugs that are not cell-specific cycles. They act by binding to DNA molecules and prevent the synthesis of RNA (ribonucleic acid), a key step in the creation of proteins, which are necessary for the survival of cancer cells.
Anthracyclines are anti-tumor antibiotics that interfere with the enzyme involved in copying DNA during the cell cycle.
Contoh anthracyclines meliputi:
- Daunorubicin
- Doxorubicin (Adriamycin®)
- Epirubicin
- Idarubicin
Anti-tumor anthracies that are not anthracyclines include:
- Actinomycin-D
- Bleomycin
- Mitomycin-C
- Mitoxantrone
Other Uses
Antimetabolites, especially mitomycin C (MMC), are commonly used in the United States and Japan in addition to trabeculectomy, a surgical procedure for treating glaucoma.
Antimetabolite has been shown to reduce site site fibrosis. Thus, its use follows external dacryosistorinostomy, a procedure for managing nasolacrimal duct obstruction, is being investigated.
Intraoperative antimetabolite applications, namely mitomycin C (MMC) and 5-fluorouracil (5-FU) are currently being tested for effectiveness in managing pterygium.
Maps Antimetabolite
Type
The main categories of these drugs include:
- base analogs (modified nucleobases) - structures that can replace normal nucleobases in nucleic acids. This means that these molecules are structurally quite similar to the replaceable DNA base components. However, since they differ slightly from the normal bases after they are inserted into the DNA, the production of DNA is stopped and the cell dies.
- purine analogues - mimicking the metabolic purine structure, larger bases are incorporated into DNA as adenosine and guanosine.
- Example: Azathioprine, Thiopurines, and Fludarabine
- pyrimidine analogues - mimicking the metabolic pyrimidine structure, smaller bases are incorporated into the DNA as cytosine and thymine.
- Example: 5-Fluorouracil, Gemcitabine, and Cytarabine
- purine analogues - mimicking the metabolic purine structure, larger bases are incorporated into DNA as adenosine and guanosine.
- nucleoside analogues - an alternative nucleoside containing nucleic acid analogs and sugars. This means it is the same base as above, but with an additional sugar group. For nucleoside analogues, the basic components or sugars can be altered. They are quite similar to the molecules used to build the cellular DNA that they are inserted by cells into their DNA, but it is quite different that after DNA cells are added they stop cell growth.
- nucleotide analogues - an alternative nucleotide containing nucleic acids, sugars, and 1-3 phosphates. This means these molecules look exactly like the pieces used to build DNA in cells and can be incorporated into the DNA of a growing cell. However, since they are analogue and therefore slightly different from ordinary nucleotides, causing cell growth to stop and cells die.
- antifolates - chemicals that block the action of folic acid (vitamin B9) needed to build DNA and allow cells to grow.
See also
- Antinutrient
References
External links
- Overview at the University of Nebraska
Source of the article : Wikipedia
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