DDT 9 Chemotherapy drugs Flashcards
(43 cards)
fundamental techniques to treat cancer
surgery
radiation therapy
chemical based approach
purpose of chemotherapy
Cure a specific cancer
Reduce the size prior to surgery
Sensitize tumour to radiation therapy
Destroy small metastases after surgery
what is chemotherapy useful for?
useful for eliminating cancers that are relatively small in size.
why are chemotherapy not used for large cancers
large cancers are not perfused by blood and thus the inner part may not be accessible to chemotherapeutic agents.
limitation of chemotherapy
the lack of selectivity of the agents for normal versus malignant cells.
assumption in chemotherapy
tumour cells - high metabolism - divide much quicker than normal cells
will uptake more chemotherapy drugs
why are the side effects of chemotherapy, hair loss,depression of
immune system and nausea.
cells that are strongly affected by chemotherapy include
hair cells
bone marrow cells
cells lining the gastro-intestinal tract
mechanism of chemotherapy
topoisomerase inhibitors Alkylating agents Antimetabolites Monoclonal antibodies intercalating agents
topoisomerase function
helps DNA uncoiling for the process of DNA replication and protein synthesis
intercalating agents
can insert into double helix of DNA and distort structure
can inhibit the enzymes involved in replication and transcription processes
Anthracyclines
naturally occurring antibiotics isolated from bacteria
have anti-cancer properties - bind to DNA structure
doxorubicin is isolated from what
streptomyces peucetius in 1967
what type of cancer does doxorubicin target
broad range of solid tumours
how does doxorubicin act against cancer
binds into DNA and acts as a topoisomerase II poison
stabilises the complex formed between DNA and topoisomerase II
Excessive no. of stabilised DNA-enzyme complexes
triggers apoptosis.
how does doxorubicin bind to DNA?
bind to CG or GC base pair to form a buckle
distort DNA structure and prevent Van der Waals forces
stabilized by - H bonding and aromatic pi bonding
Dactinomycin is isolated from what
S. parvullus
what does dactinomycin contain
3 fused aromatic rings
Two identical pentapeptide side chains
what tumour does the dactinomycin target?
pediatric solid tumours
where does dactinomycin bind to DNA and what holds the drug in place?
between GC base pairs
favours intercalation between 2 G bases on diff. strands
Held by aromatic pi stacking interactions between tricyclic ring and
tubulin
strucutral protein - crucial to cell division
acts as building block for microtubules - polymerised and depolymerised in cell division
how do drugs block the process of microtubules
Drugs can block this process by either binding to tubulin to prevent
polymerization or binding to the microtubules to prevent
depolymerisation
why do anti cancer cells acting on tubulin effective in inhibiting cancerous cell division
cancer cells divide rapidly through mitosis and need microtubules for division
where does vincristine bind to
bind to tubulin inhibiting assembly of microtubule
stops mitosis in metaphase and prevent cell replication
what types of cancers does vincristine work for?
work w/ other drugs for non-Hodgkins lymphoma and childhood leukemia
