MEDC0013 - Chemotherapy Exam Latest Update
antimicrobial chemotherapy - ANSWER a drug given to an infected person that destroys
the infective microorganisms without harming the host's cells
cancer chemotherapy - ANSWER cytotoxic agents that kill cancer cells, however, also
harm host cells
Alkylating agents - ANSWER chemotherapeutic synthetic drugs that cause crosslinks
and breaks in DNA to stop cells from dividing
form covalent bond with bases in DNA - inducing apoptosis
Nitrogen Mustards - ANSWER alkylating agents
example of Nitrogen Mustards - ANSWER cyclophosphamide
cyclophosphamide - ANSWER a derivative of nitrogen mustard (alkylating agent )
phosphorylated form is a pro-drug , actively transported into cells - once in cells the
pro-drug is enzymatically converted into the toxic, active form
cyclophosphamide side effects - ANSWER cytotoxic agent (not selective for cancer
cells)
general - hair loss, GI disturbance, nausea, vomiting, anaemia, immune supression
specific - hemorrhagic cystitis (accumulation of metabolite acrolein in urine) due to
urinary excretion of acrolein metabolite
how to reduce side effects of cytotoxic chemotherapeutic targets - ANSWER - give
treatment in courses - allow recovery of normal cells
antineoplastic - ANSWER pertaining to the prevention of the growth and spread of
cancer cells
antineoplastic resistance - ANSWER
Why is exposure to cyclophosphamide not dangerous if it is a derivative of nitrogen
mustard? - ANSWER because it is a pro-drug so it only becomes activated into the toxic
form enzymatically in the cells
Why does cyclophosphamide not have an effect on non-rapidly dividing cells? - ANSWER
because in healthy cells, the DNA is kept in histones and so the actual DNA is not
accessible
however, in cancer cells that are rapidly dividing, the DNA is constantly exposed
allowing the drug to access the guanine bases
, Why do cyclophosphamide also harm some healthy cells? - ANSWER because we have
some healthy cells in our body that are always dividing e.g. hair follicles and therefore,
their DNA Is accessible and the cyclophosphamide drug can access the guanine bases
and kill the cells
Why is it almost impossible to kill ALL cancer cells using chemotherapy? - ANSWER
because some cells lay dormant
What is mesna used for in chemotherapy? - ANSWER it protects the bladder against
some of the harmful effects of chemo
How does mesna work to protect the bladder from cyclophosphamide? - ANSWER
mesna detoxifies acrolein, a urologic breakdown product of cyclophosphamide that
accumulates in the bladder producing a non-harmful product that gets excreted in the
urine
What is the problem with using only 1 chemotherapeutic agent? - ANSWER resistance
How can cancer cells evolve resistance to a chemotherapeutic agent? - ANSWER -
mutations causing a defect in an apoptotic pathway
- mutation that enhances DNA repair mechanisms
- Altered membrane transport e.g. up regulation of the ABC transporter responsible for
removing chemicals inside cells
- enhanced enzymatic deactivation
Why does combination therapy improve the effectiveness of chemotherapy? - ANSWER
because using more than 1 chemotherapeutic agent increases the likelihood of cells
avoiding resistance
What are the side effects of using cisplatin as a chemotherapeutic agent? - ANSWER
terrible nausea and vomitting
What causes spina bifida? - ANSWER Folate deficiency
Someone with folic acid deficiency can't make [?]. Why is this? - ANSWER They can't
make thymidine because the activity of thymidylate synthase is impaired
How does inhibiting formation of thymidine inhibit DNA replication? - ANSWER thymidine
formation is essential for DNA synthesis. By inhibiting this, cells cannot replicate their
DNA
What chemotherapeutic agents work by inhibiting thymidine formation? - ANSWER 1.
5-FU (5-fluorouracil)2. methotrexate
What are 2 examples of cytotoxic agents derived from bacteria? - ANSWER 1.
doxorubicin
antimicrobial chemotherapy - ANSWER a drug given to an infected person that destroys
the infective microorganisms without harming the host's cells
cancer chemotherapy - ANSWER cytotoxic agents that kill cancer cells, however, also
harm host cells
Alkylating agents - ANSWER chemotherapeutic synthetic drugs that cause crosslinks
and breaks in DNA to stop cells from dividing
form covalent bond with bases in DNA - inducing apoptosis
Nitrogen Mustards - ANSWER alkylating agents
example of Nitrogen Mustards - ANSWER cyclophosphamide
cyclophosphamide - ANSWER a derivative of nitrogen mustard (alkylating agent )
phosphorylated form is a pro-drug , actively transported into cells - once in cells the
pro-drug is enzymatically converted into the toxic, active form
cyclophosphamide side effects - ANSWER cytotoxic agent (not selective for cancer
cells)
general - hair loss, GI disturbance, nausea, vomiting, anaemia, immune supression
specific - hemorrhagic cystitis (accumulation of metabolite acrolein in urine) due to
urinary excretion of acrolein metabolite
how to reduce side effects of cytotoxic chemotherapeutic targets - ANSWER - give
treatment in courses - allow recovery of normal cells
antineoplastic - ANSWER pertaining to the prevention of the growth and spread of
cancer cells
antineoplastic resistance - ANSWER
Why is exposure to cyclophosphamide not dangerous if it is a derivative of nitrogen
mustard? - ANSWER because it is a pro-drug so it only becomes activated into the toxic
form enzymatically in the cells
Why does cyclophosphamide not have an effect on non-rapidly dividing cells? - ANSWER
because in healthy cells, the DNA is kept in histones and so the actual DNA is not
accessible
however, in cancer cells that are rapidly dividing, the DNA is constantly exposed
allowing the drug to access the guanine bases
, Why do cyclophosphamide also harm some healthy cells? - ANSWER because we have
some healthy cells in our body that are always dividing e.g. hair follicles and therefore,
their DNA Is accessible and the cyclophosphamide drug can access the guanine bases
and kill the cells
Why is it almost impossible to kill ALL cancer cells using chemotherapy? - ANSWER
because some cells lay dormant
What is mesna used for in chemotherapy? - ANSWER it protects the bladder against
some of the harmful effects of chemo
How does mesna work to protect the bladder from cyclophosphamide? - ANSWER
mesna detoxifies acrolein, a urologic breakdown product of cyclophosphamide that
accumulates in the bladder producing a non-harmful product that gets excreted in the
urine
What is the problem with using only 1 chemotherapeutic agent? - ANSWER resistance
How can cancer cells evolve resistance to a chemotherapeutic agent? - ANSWER -
mutations causing a defect in an apoptotic pathway
- mutation that enhances DNA repair mechanisms
- Altered membrane transport e.g. up regulation of the ABC transporter responsible for
removing chemicals inside cells
- enhanced enzymatic deactivation
Why does combination therapy improve the effectiveness of chemotherapy? - ANSWER
because using more than 1 chemotherapeutic agent increases the likelihood of cells
avoiding resistance
What are the side effects of using cisplatin as a chemotherapeutic agent? - ANSWER
terrible nausea and vomitting
What causes spina bifida? - ANSWER Folate deficiency
Someone with folic acid deficiency can't make [?]. Why is this? - ANSWER They can't
make thymidine because the activity of thymidylate synthase is impaired
How does inhibiting formation of thymidine inhibit DNA replication? - ANSWER thymidine
formation is essential for DNA synthesis. By inhibiting this, cells cannot replicate their
DNA
What chemotherapeutic agents work by inhibiting thymidine formation? - ANSWER 1.
5-FU (5-fluorouracil)2. methotrexate
What are 2 examples of cytotoxic agents derived from bacteria? - ANSWER 1.
doxorubicin
