Anticancer Flashcards
What are intercalating drugs
Drugs that distort DNA double helix via pi-bonding of flat aromatic structures
Dactinomycin
They are intercalating agents
Intercalation via planar phenoxazone ring system C - G base pairs
Contains additional H bonding with cyclic peptides
Doxorubicin
Has 3 mechanism of action
Intercalation via tetracyclic system
Additional bond between phosphate on DNA backbone and ammonium group = stabilisation of DNA topoisomerase II
Chelate metal ions
cardiotoxic
Mitoxantrone
Intercalation
Bond between phosphate on DNA backbone with amino group
Can chelate metal ions
Less cardiotoxicity - no sugar moiety
Bleomycin
Intercalation via bithiazole rings
Production of free radicals via N atoms
N atoms can chelate metal ions
Non-intercalating drugs
Stabilise DNA topoisomerase II
Can produce free radicals
Camptothecins
Stabilise DNA topoisomerase I
Induce production of destructive enzymes
Chlormethine
Alkylating drug
Causes DNA linkage
Cyclophosphamid
Alkylating drug
Phosphoramide group reduces nucleophilicity of N = more reactive
Nitrosourea
Alkylating agent
Can pass through BBB
Carbamoylation of protein and alkylation of DNA between C-G
Cisplatin
Alkylating agent
Replacement of Cl by water = positively charged and reactive ligands
Binds to regions with high concentration of guanine = transcription inhibited
Dacarbazine and procabazine
Non-alkylating agent
Methylation of DNA but no cross linking
Mitomycin C
Converted into alkylating agent in vivo
What are dihydrofolate reductase inhibitors
Catalyse reduction of folic acid to tetrahydrofolate
Methotrexate
5-fluorouracil
Thymidylate synthase inhibitor
Converted into analogue of dUMP in vivo
Stops synthesis of thymidine due to covalent bond
DNA polymerase inhibitors
Mimic deoxynucleotides to act as false substrate for DNA polymerase
Purine antagonist
Converted to thio-dGTP
Causes cell death