Targeted Cancer Therapy Flashcards
What are the three definitions of targeted cancer therapy
1) Act on specific molecular targets associated with cancer
2) Targeted therapies are deliberately chosen or designed to interact with their target
3) Targeted therapies are often cytostatic, blocking tumor cell proliferation
What are key differences between targeted therapies and chemotherapy
Chemotherapies act on ALL rapidly dividing normal AND cancerous cells, standart chemotherapies were identified because they kill cells, chemotherapy agents are most often cytotoxic
How does tamoxifen work against breast cancer
Works as antangonist when bound to the estrogen receptor causing different gene products to be synthesized when acting as a transcription factor
T/F: Targeted therapies do not necessarily target cancer cells but target a specific biomolecule driving growth, survival, or spreading of cancer cells
True
What are consequences of targeted therapies being cytostatic instead of cytotoxic
Adeverse events are linked to on-target effects of the target biomolecule in normal cells, resistance occurs through a mutated target or upregulated pathways circumventing the target
Which cancer therapies are most known to have resistance
Tyrosine kinase inhibitors, Receptor and RTK antagonists, antimetabolites, and DNA targeting agents
What are three ways receptor tyrosine kinases are targeted extracellularly
Antibodies bind the receptor, antibodies binding the ligand of the receptors, antibodies inhibit dimerization
What are the ways receptor tyrosine kinases are targeted intracellularly
Small molecules inhibit the receptor, small molecules inhibit downstream signaling
What is the receptor tyrosine kinase antibody that is a humanized mouse monoclonal antibody, what does it bind
Bevascizumab (Avastin), binds VEGF-A blocking activation of VEGFR-A preventing blood supply to tumors (anti-angiogenic)
What is the receptor tyrosine kinase antibody that is chimeric antiobdy, what is a caveat of it working properly
Cetuximab (Erbitux), blocks gowth factor binding/ no effect in mutant kRAS
What is the key characteristic that is found in chronic myeloid leukemia (CML)
Translocation from chromosome 9 to chromosome 22 creating the protien BCR/ABL leading to uncontrolled cell growth and proliferation in white blood cells
In patients with CML what is the previous domain that negatively regulates the activity of ABL, what is the target for patients with CML
SH3 domain (BCR/ABL fusion produces an abnormally active tyrosine kinase),
What is the first generation tyrosine kinase inhibitor, MOA
Imatinib: competitively binds to the active site where ATP would bind allowing for no phosphorylation
What is the biggest resistance to Imatinib
Point mutations in the BCR-ABL kinase domain that affect imatinib binding
What second generation TKI was approved for patients with resistance or tolerance to imatinib in chronic, accelerated or blast phase in CML, what makes it different
Dasatinib: inhibits multiple oncogenic tyrosine kinases including BCR/ABL and SRC family kinases while being more potent imatinib and having activity against nost common resistant mutations
T/F: Second generation TKIs do not develop resistance
False: Dasatinib can develop secondary resistance in 3 to 12 months
Which EGFR inhibitor (TKI) is used in advanced metastastatic Non-small cell lung cancer (NSCLC), what other is used but known for having a specific mutation, what other inhibits EGFR and HER2 but also has a downside, which is effect against a specific mutation
Gefitinib: binds to the ATP binding site of the enzyme (only works in mutant and overexpressed EGFR), Erlotinib: T790M mutation in within 12 months, Afatinib: inhibits EGFR and Her2 BUT NOT EFFECTIVE in T790 mutant, Osimertinib: T790M mutant EGFR
What is the most common adverse effect of EGFR inhibitors, what does it signify
Papulopustular rash that spreads across the face and torso (90%), the rash indicates the drug’s antitumor effect is working
What are RTK inhibitors that have broad kinase inhibition (VEGFR, PDGFR, FLT3), which has more
Sorafenib and Sunitinib, Sunitinib ( RET, cKIT, and CD135)
