Cancer Chemotherapy Flashcards
1
Q
Trastuzumab
A
- monoclonal antibody against HER2/NEU R tyrosine kinase, prolonged survival
- combined w/ cytotoxic chemotherapy
- Use: specific breast cancers
- MOA: overexpress HEGFR2 (HER2) in primary breast CA= poor prognosis.
Binds with high affinity to HER2 R, inhibit tumor growth. - Tox: nausea & vomit, chills, fever, headaches & rahses.
Most serious: cardiac fail w/ v dys.
Before starting need baseline EKG & ejection fraction.
2
Q
Imatinib Mesylate
A
- inhibits BCR-ABL tyr kinase in CML
- targeted prot kinase inhibitor
- Use: CML, GIST
- MOA: inhibits prot tyr kinase encoded by BCR-ABL oncogene.
Inhibits phosphorylation of kinases. Induce apoptosis.
3
Q
Methotrexate
A
- antifolate
- blocks DHF reductase
- S phase
4
Q
5 FU
Cytarabine
Floxuridine
A
- pyrimidine analogues
- Inhibit thymidylate synthase
- Inhibit DNA pol
- Block thymidylate synthase
- S phase
5
Q
Mercaptopurine
Hydroxyurea
A
- purine analogues
- inhibit purine nt. interconversions
- inhibit ribonucleotide reductase. Stops conversion of ribont to deoxyribont. Used in myeloproliferative disorders
- S phase
6
Q
Bleomycin
A
- fragments DNA
2. G2 phase
7
Q
Vincristine
Vinblastine
A
- bind to tubulin & block polym of MT
- M phase
- Vinca alkaloids
8
Q
Paclitaxel
A
- promote MT formation, prevent depol
- M phase
- Taxane
9
Q
Tamoxifen
A
- interfere with specific gene transcription
- G1 phase
- antiestrogen
10
Q
Etoposide
A
- interfere w/ topo II
- Epidophyllotoxin
- between S & G2
11
Q
Dactinomycin
A
- binds to DNA & inhibits DNA dep RNA synthesis by preventing transcription of DNA by RNA polym
- Cytotoxic antibiotic
- between S & G2
12
Q
Cyclophosphamide
Busulfan
A
- prodrug
- effective in all cells whether cycling or not
- alkylating agent
13
Q
Doxorubicin
Daunorubicin
A
- Antitumor antibiotics
2. act in all cells
14
Q
Log-Kill concept
A
- drug or irradiation therapy kills constant proportion of cells in pop, not fixed #
- 1 log kill means 90% decrease in cell pop when drug with 1 log kill is given; drug with 3 log kill means 99.9% killed
- smaller tumor means greater proportion of cells are killed but in between cycles will regrow faster
- want to achieve a selective log-kill of nepolastic cells without toxicity to bone marrow & other rapidly proliferating cells. Avoid development of resistance during chemotherapy.
15
Q
Dose limiting toxicity
A
- all cytotoxic drugs are toxic to all cells dose depending
- Some drugs are cumulative, irrev, toxic towards organ. (methotrexate, cisplatin, doxorubicin, bleomycin, vincristine)
16
Q
Resistance
A
- cancer cells are gene labile, can produce resistance
- FU inhibits thymidylate synthase: cancer cell then produces isoenzyme with reduced sensitivity to drug.
- mercaptopurine- nt derivative, inhibits enz in purine interconversions, cancer cell produces enz that are less sensitive.
- methotrexate polyglutamated form inhibits DHF reductase: cancer cell causes reduced polyglutamation effect- drug less able to inhibit DHFR
17
Q
Resistance
A
- change R affinity: methotrexate R
- change in expression of drug transporter GP (Pgp) so increase transport of drug out of cell (dactinomycin, doxorubicin, etoposide, vincristine, vinblastine, paclitaxel) mdr gene
- modify in production of drug inactivating enz or of endogenous molecs which inactivate drug- cancer cell achieves R to drugs (cytarabine & mercaptopurine)
18
Q
Resistance
A
- Enhanced activity of enz which reseal DNA strand breaks result in increased DNA repair. Reduce (cisplatin, cyclophosphamide & other alkylating agents= mismatch repairs)
- Reduce drug activation cytarabine, doxorubicin, FU, mercaptopurine, methotrexate, thioguanine
- Alteration of p53 pathway