Chemotherapy (10.2) Flashcards
Name two Antimetabolites
5-Fluorouracil
Methotrexate
What is the mode of action of 5-Fluorouracil?
Activated to 5dUMP
Irreversibly inhibits thymidylate synthase
Pyramidines cannot be incorporated into the DNA
What is the mode of action of Methotrexate?
Inhibits Dihydrofolate reductase so folate cannot be used for synthesis of purines & thymines
Name an Alkylating agent
Platinum compounds eg Cisplastin
What is the mode of action of Alkylating agents?
Forms covalent bonds between the DNA strands so they cannot unwind for replication
Give examples of Intercalating agents
Anthracycline Antibiotics
Topoisomerase II
Glycopeptide Antibiotics (Bleomycin)
What is the mode of action of Bleomycin?
Intrercalates into the DNA structure
Binds to the DNA via a terminal NH2
Degrades the DNA phosphodiester bonds so fragments the DNA
What is the mode of action of Intercalating agents?
Discrete molecular ring structures that can go between the spaces of the DNA base pairs to cause issues with transcription and replication
Give two examples of Spindle poisons
Vinca alkaloids (Vincristine, Vinblastine) Taxanes (Paclitaxel)
What is the mode of action of Vinca alkaloids?
Bind to a beta tublin unit so the mitotic spindle cannot form and chromosomes cannot separate.
The cell becomes arrested in mitotic metaphase and apoptosis occurs
What is the mode of action of Taxanes?
Bind to the beta tublin unit to stabilises the microtubules and prevent their disassembly.
This means the chromosomes cannot be pulled apart and the cell is arrested in mitosis causing apoptosis.
How can cells become resistant to chemotherapy?
Decreased entry or Increased removal of agent
Inactivation of agent in the cell
Increased repair of DNA lesions produced by alkylation
