Chemotherapy Flashcards
(20 cards)
What are the five main classes of cytotoxic anticancer agents?
Alkylating agents, Antitumour antibiotics, Antimetabolites, Topoisomerase inhibitors, Spindle-tubule inhibitors
What is the mechanism of action of alkylating agents?
Alkylation of guanine in DNA, leading to crosslinking and inhibition of DNA replication and transcription
Give an example of a platinum-based alkylating agent.
Cisplatin or Carboplatin
What do antimetabolites do?
Mimic natural metabolites to disrupt DNA/RNA synthesis by interfering with enzyme function or incorporation into DNA/RNA
Name two examples of pyrimidine analogue antimetabolites.
Fluorouracil (5-FU), Cytarabine
How do spindle-tubule inhibitors like vincristine act?
Disrupt microtubule formation, preventing mitotic spindle formation and causing metaphase arrest
What do taxanes like paclitaxel do?
Stabilize microtubules and prevent their disassembly, arresting cells in mitosis
What is the role of Topoisomerase II inhibitors (e.g., etoposide)?
Trap the enzyme-DNA complex, leading to DNA double-strand breaks and G2/M cell cycle arrest
What is a key transcription factor activated in response to DNA damage?
p53
What does p53 upregulate to cause cell cycle arrest?
p21 (Cip1/Waf1)
What are common mechanisms of drug resistance in cancer?
Efflux pumps (P-gp), enhanced DNA repair, apoptosis resistance (e.g., Bcl-2 overexpression), p53 mutation
What is the function of BH3 mimetics (e.g., ABT-263)?
Block anti-apoptotic proteins like Bcl-2 to promote apoptosis
What is the purpose of CDK inhibitors?
Block overactive cyclin-dependent kinases that drive unregulated cell proliferation in cancer
What is flavopiridol?
A small molecule inhibitor that targets CDKs by binding to the ATP-binding site
What are nutlins and how do they work?
Small molecules that inhibit MDM2, leading to p53 stabilization and activation of its apoptotic and cell cycle arrest functions
What does HIF-1α do under hypoxic conditions in tumours?
Promotes VEGF expression, angiogenesis, and adaptation to low oxygen
Name a monoclonal antibody that targets HER2 in breast cancer.
Trastuzumab (Herceptin)
What are the three main functions of trastuzumab?
- Blocks HER2 signaling
- Triggers immune-mediated cytotoxicity
- Enhances chemotherapy sensitivity
What are three mechanisms by which biological therapies inhibit angiogenesis?
Block angiogenic signals (e.g., VEGF), bind VEGF directly, inhibit endothelial cells or matrix degradation
What is synthetic lethality in cancer therapy?
Targeting a second gene or pathway that becomes lethal only when a specific cancer-related mutation is present (e.g., BRCA + PARP inhibitor)
