anticancer alkylating agents Flashcards

1
Q

what do they contain and do to nucleophilic substances in cells

A

contains chemical groups which form covalent bonds

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2
Q

what do alkylating agents do

A

formation of a carbonium ions
highly reactive
reacts instantaniously with electron donor

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3
Q

what do most alkylating agents contain

A

2 alkylating groups

bifunctional

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4
Q

what is the main target

A

N at position 6 of guanine

which is strongly nucleophilic

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5
Q

what does the reaction cause

A

causes intra and inter chain cross-linking

interferes with transcription and replication

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6
Q

what can alkylating guanine do

A

can pair with thymine

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7
Q

whats the main impact

A

during S phase

as there are zones of DNA that are unpaired

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8
Q

what are the side effects of alkylating agents

A

depress bone marrow
GI disturbances
increased risk of acute non-lymphocytic leukaemia

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9
Q

prolonged use gives what

A

depression of gametogenesis

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10
Q

nitrogen mustards

what happens to the side chains

A

each 2-chloroethyl undergoes an intramolecular crystalisation with the release of a Cl-
with nucleophilic centres

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11
Q

what interacts with the DNA

A

highly reactive ethylene immonium derivative

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12
Q

what do nitrogen mustards cause

A

cross linking of DNA strands

1 reaction with 1 strand and the other with the other

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13
Q

what does the cross linking do in nitrogen mustards

A

dna cannot replicate
recognised as damaged
induces apoptosis

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14
Q

what resistance forms

A

up regulation of repair system

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15
Q

mono-alkylators are not anticancer but are

A

mutagenic

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16
Q

what is another alkylating agent

A

cyclophosphamide

17
Q

cyclophosphamide

how is it activated

A

metabolised by p450
producing phosphoramide mustard
and acrolein

18
Q

cyclophosphamide

what does acrolein cause

A

dose limiting

has bladder toxicity

19
Q

cyclophosphamide

how to over come acrolein

A

combo with MESNA

which is a small molecule to react with acrolein

20
Q

cyclophosphamide

what does it affect

A

lymphocytes

used in immunosuppression

21
Q

cyclophosphamide

what are the toxic effects

A

nausea
vomiting
bone marrow depression
haemorrhagic cystitis

22
Q

nitrosoureas examples

A

lomustine and carmustine

23
Q

what do nitrosoureas do that nitrogen mustards cant

A

lipid soluble

crosses bbb

24
Q

disadvantages of nitrosoureas

A

severe cumulative depressive effects on bone marrow

stands 3- 6 weeks after

25
Q

other alkylating agents

A

Busulfan

26
Q

Busulfan what is it selective for

A

bone marrow

27
Q

Busulfan in low dosages have

A

depressing formation of granulocytes and platelet

28
Q

where is Busulfan used

A

chronic granulocytic leukaemia