L08: Chemotherapy Mechanims Of Action Flashcards
What are the 3 main modalities of treating cancer
Surgery
Radiotherapy
Chemotherapy
What treatment modality does cytotoxic drugs belong to
Chemotherapy
What is the therapeutic index of cytotoxic drugs like
Narrow
What does a narrow therapeutic index mean
Agents that target the diving cells (tumour cells) can affect normal healthy cells that are also dividing
Can normal cells recover from cytotoxic injury
Yes
What structures and cells does cytotoxic drugs affect
Bone marrow GIT Germinal epithelium Lymphoid tissue Hair follicles
Are cytotoxic drugs targeted drugs
No
If cytotoxic drugs are not targeted drugs what vital organs can they affect
Kidney
Nerves
Heart
Lungs
What can the affect of cytotoxic drugs on these organs cause
Renal failure
Nerve damage
Heart failure
Lung fibrosis
What does genotoxic mean
Toxic (Damaging) to DNA
Are cytotoxic drugs genotoxic
Yes
If cytotoxic drugs are genotoxic what can this lead to
Mutations
What can mutations in people using cytotoxic drugs result in overall
Secondary malignancy
When increasing the dose of cytotoxic drugs to get an anti cancer effect what chance also increases
Toxicity
What are the 10 hallmarks of cancer
1) sustaining proliferative signalling
2) evading growth suppressors
3) enable replicative immortality
4) resisting cell death
5) activating invasion and metastasis
6) inducing angiogenesis
7) deregulating cellular energetic
8) avoiding immune destruction
9) tumour promoting inflammation
10) genome instability and mutation
If we know the hall marks of cancer what can we do
Molecular target and engineer drugs that hit those targets
Which patients is molecular targeted drugs likely to work on
Specific patients based on the molecular properties of cancer
Compare cytotoxic drugs and molecules targeted drugs in terms of the cancer they can target and toxicity
Cytotoxic drugs: effective against a broad number of cancer, but toxic
Molecular targeted drugs: effective against specific cancer and less toxic
What does cytotoxic drugs work on in the cell
Cell cycle
How do different agents work on the cell cycle
Different agents have different effects on the cell cycle
Name the different cytotoxic drugs that we use
Micro-tubule inhibitors Topoisomerase inhibitors Alkylating agents Anti-metaboliities Platinum analogues
What is p53
A tumour suppressor gene
When there is cytotoxic damage what happens to P53
Plays a role in detecting cytotoxic and genotoxic damage then transcriptional activator to mediate G1, G2 cell cycle arrest or apoptosis
In many cancers what is p53 like
Lost or mutated so it is inactive
In chemotherapy what are we trying to trigger
Apoptosis
What are the 2 pathway of apoptosis
Intrinsic pathway
Extrinsic pathway
What does the intrinsic pathway involve
1) genotoxic damage is detected
2) cytochrome c is released from the mitochondria
3) cytochrome c binds to a path 1 activator
4) caspase 9 is activated with results in apoptosis
What does the extrinsic pathway involve
1) pathway relies on tumour necrosis family receptor (TNFR)
2) TNFR activates caspase that initiates apoptosis
Which pathway does agents select for apoptosis
Different agents select different pathways either intrinsic or extrinsic
What protein does some cancer release that increases the threshold for apoptosis
BCL-2
What has to happen for the intrinsic pathway to become activated
DNA damage from chemotherapy
What detects the cellular stress in the intrinsic pathway to activate it
P53 detect DNA damage and activates the intrinsic pathway
What determines the activation of the extrinsic pathjwaty
Condition in the extracellular environment
What phase of the cycle does anti-metabolites work at
DNA synthesis (s phase)