2015 Antineoplastics

Example QuestionRESISTANCE MECHANISMS

  1. alterations that affect the mechanism of action of the drugs:

    1. increased DNA repair: crosslinking agents, bleomycin
    2. formation of trapping agents: crosslinking agents
    3. changes in target proteins (esp. enzymes): drugs that prevent DNA synthesis, some natural products, signal transduction inhibitors, antibodies
  2.  

  3. alterations that affect drug concentrations INSIDE THE TUMOUR CELL:
    1. decreased activation of prodrugs: 5-FLUOROURACIL, CYCLOPHOSPHAMIDE, IRINOTECAN/TOPOTECAN
    2. increased inactivation: antimetabolites (esp. purine analogues)
    3. decreased accumulation:
      1. decreased transport into the cell: folate analogues, MECHLORETHAMINE, platins
      2. increased export from the cell due upregulation of efflux transporters (esp. increased P-glycoprotein): natural products (esp. anthracyclines, vinca alkaloids, taxanes, epipodophyllotoxins)
Email: Dr. Janet Fitzakerley | ©2015 University of Minnesota Medical School Duluth | Last modified: 11-apr-15 9:39 AM