the approach to treat cancer depends on —
stage, type , location of the cancer
several techniques for treating cancer:
- chemotherapy ( reduces the size , cure specific cancer, destroy small metastases after surgery, sensitive tumor to radiation therapy , it useful for eliminating cancer that are small in size and not larger cancers bc they are NOT perfused by blood and not accessible to the chemotherapeutic agents )
- surgery
- radiation therapy
chemotherapy works for — sized cancer bc they access the chemotherapeutic agents
they however lack —- of the agents for normal vs malignant cells
this treatment relies of — that malignant cells takes up extra cellular material at greater rate than normal cells
the side effects include:
- small sized
- selectivity
- assumption
- hair loss, bone marrow cells , lining of the GI tract , depression of the immune system , and nausea
mechanisms of chemotherapy
1- topoisomerase inhibitor: prevents dna coiling
2- interference w/ microtubule function: prevents mitosis
3- alkylating agent: interferes w/ base pairing leading to strand breaks and arrest dna replication
4- antimatoblites: block the formation and use of nucleic acids essential for dna replication
5- monoclonal antibodies: recognition of over expressed antigens on cancer membrane
intercalating agents contain — or —- ring system which can insert into the double helix of dna and distort its fucntion
once bound the drug inhibits the — involved in replication and transcription process
- planer aromatic or hetro aromatic ring
- enzyme
—- are set of naturlly occurring antibiotic which isolated from bacteria which have anti-cancer properties with mode of action involving dna intercalation
- anthracyclines
– an intercalating agent and is one of the most effective anti cancer agents and is used to treat broad spectrum of solid tumours
it intercalates into the dna and acts as —- as it stabilises the complex formed between dna and topomerase II
excessive number of stabilised sna-nzyme complexes triggers —
- doxorubicin
- topomorise II poison
- apotosis
mode of action of deoxorubicin biding to the dna:
- inserts GC and CF base pairs causing a “buckle”
which prevents the van Der Waals contact and distorts the dab structure - stabilised by : hydrogen bonding and aromatic pi interactions
dactinomycin contains – fused aromatic rinds and — pentane-tide side chains and is used of treatment of —–
- 3 fused
- 2 identical
- pediatric solid tumours ( RECOGNIZE THGE STRUCTYRE )
dactinomyin bound to dna mode of action:
- interrelates between c,g dna bases
- favours intercalation between 2 adjacent G bases on alternative strand of the helix
- held by somatic pi-pi stacking interaction between tricyclic ring and dna bases
- further stabilised by peptide hydrogen-hydrogen to nucleic acid bases of dna as it interferes w/ topomirese II and inhibits replication and transcription
—- binds to tublin inhibiting the assembly of microtubules structures.
It stops mitosis in the —- which prevents cell replication
used in:
- vincristine
- metaphase
- non-hodgkins lymphoma and children luckemia
— stabilises the microtubules which interferes with normal breakdown of microtubule during cell division
It blocks the progression of mitosis and triggers apotosis
used in:
- paclitaxel
- ovarian, breast, lung , bladder , prostate cancers
because cancer cells rapidly divides the — drugs are effective at inhibiting the cancerous cell divison
- anticancer drugs acting on tublin ( tublin is a structural protein for cell diviosn and the protein acts as a building blocks for microtubule which are polymerised and depolymerised during cell divison )
— are highly electrophilic groups which forms covalent bonds to nucelphilic groups on dna ( as N-7 on G )
prevents replication and transcription and is useful anti-cancer agent
alkylating anti-cancer agents which can cause intertsrand and intrastrand cross linking if 2 electrophilic groups are present
alkylatation of nucleic acid bases result in —-
and the toxic side effects bc of —
- miscoding
- non-selective alkylation
an example of alkylating agent is — which is also a —– and it causes intrastrand and intestrand corsslinking and prevents cell replication and monoalkylation of guanine is possible
- chloromethine
- nitrogen mustard
