Chemotherapy Flashcards
Describe some different methods of cancer treatment
Surgery
Chemotherapy - oral and IV
Radiotherapy
Targeted therapies e.g. immunotherapy
Name the different classes of anti-cancer therapeutics COME BACK
Alkylating agents
Antimetabolites
Vinca Alkaloids
Taxanes
Antimitotic Antibiotics
Immunotherapy with monoclonal antibodies
Targeted drugs
Hormonal drugs
Describe the mechanism of action of the alkylating agents class of chemotherapy drugs
Alkylating agents e.g. cisplatin, bisulfan
• Alkyl groups of the drugs allow covalent bonds to form between the drug and DNA
• In this case, it attaches to the guanine between DNA strands at N7 during replication, preventing it from taking place since the strands cannot separate.
What type of drugs are cisplatin, carboplatin and bisulfan?
Alkylating agent
Describe some mechanisms of resistance to alkylating agents
Mechanisms of resistance include:
o Decreased entry or increased removal of a drug by the cell
o Inactivation of the drug by the cell e.g. glutathione
o Enhanced repair of affected DNA by DNA repair enzymes
Describe the mechanism of action of antimetabolite drugs
Similar chemical structure to essential metabolites required by cell prior to cell division.
May be incorporated into new nuclear material or bind irreversibly with vital enzymes to inhibit cell division:
o E.g. antagonise folic acid (methotrexate),
o Antagonise purine (6-mercaptopurine, 6-thioguanine),
o Inhibit thymidylate synthase (5-fluorouracil),
o Incorporate fluoridated nucleoside in place of normal nucleoside (5FU instead of uracil in RNA)
What is methotrexate and what is its mechanism of action?
Antimetabolite, antagonises folic acid synthesis and therefore inhibits purine synthesis
What is 6-mercaptopurine and what is its mechanism of action?
Antimetabolite which inhibits purine synthesis
What is 5-fuorouracil and what is its mechanism of action?
Antimetabolite which inhibits thymidylate synthase and is incorporated into the place of uracil in RNA to prevent transcription
Name two classes of drugs that are derived from plants which act as spindle poisons
Vinca alkaloids
Taxanes
Describe the mechanism of action of vinca alkaloids
Vinca alkaloids - these drugs bind to tubulin and inhibit its polymerisation into microtubules, preventing spindle formation in dividing cells and causing arrest at metaphase. Their effects manifest only during mitosis. They also inhibit other cellular activities that involve the microtubules, such as leukocyte phagocytosis and chemotaxis, as well as axonal transport in neurons. E.g. vincristine
What is vincristine?
Vinca alkaloid
Describe the mechanism of action of taxanes
Taxanes - act on microtubules, stabilising them (in effect ‘freezing’ them) in the polymerised state, achieving a similar effect to that of the vinca alkaloids. E.g. Paclitaxel (IV) and docetaxel (oral)
Give some examples of taxmen drugs
Paclitaxel and Docetaxel
How is paclitaxel administered?
Oral