41 Questions
What is the term used to describe the process where cancer cells invade other parts of the body and set up secondary tumors?
Metastasis
Which disease caused a quarter of all deaths in 2000 according to the WHO?
Cancer
What is the term used to describe new growth and is considered a more accurate term for cancer?
Neoplasm
What is the characteristic of cancer cells that distinguishes them from normal cells?
Loss of differentiation
What is the term used to describe a local swelling, often caused by cancer?
Tumor
What regulatory mechanisms do cancer cells lose that lead to uncontrolled growth and multiplication?
Cell cycle checkpoints
Which of the following is NOT a common cause of genetic mutations that can lead to cancer?
Sunlight exposure
Which type of agents acts directly on existing DNA to selectively destroy a tumor or limit its growth?
Drugs that inhibit DNA synthesis
Which type of DNA interactive agents can form cross-links between two complementary DNA strands?
Alkylating and methylating agents
Which of the following is NOT a characteristic of cancer?
Increased cellular differentiation
Which type of agents interferes with DNA replication by forming bridges within a single DNA strand?
Bifunctional agents
Which of the following is NOT a type of DNA interactive agents that are used in cancer chemotherapy?
Drugs targeting cellular metabolism
Which of the following is NOT a common event leading to the accumulation of mutations in oncogenes and tumor suppressor genes?
Transcriptional errors
Which of the following is the most significant cause of cancer deaths?
Metastases
Which type of drugs is the most widely used group in the clinical practice of cancer chemotherapy?
DNA interactive agents
Which of the following is NOT a common cause of genetic mutations that can lead to cancer?
Aging
What is the primary cause of mispairing of nucleotides due to alkylation?
The displacement of tautomeric equilibrium to the more stable enol form
Which type of alkylation agent can form bridges within a single DNA strand?
Bi-functional agents
What is the primary mechanism of cytotoxicity induced by alkylation agents?
Induction of mispairing of nucleotides
What is the result of tautomeric equilibrium being displaced to the more stable enol form in alkylated G?
H-bonding with cytosine is weakened
What is the primary cause for the cytotoxicity of bi-functional agents?
Formation of bridges between two complementary DNA strands
What is the primary cause of DNA fragmentation by hydrolytic reactions and by the action of repair enzymes?
The attempt of repair enzymes to excise alkylated bases
What is the main reason why bifunctional alkylating agents are considered more cytotoxic than monofunctional ones?
There is a direct correlation between the degree of interstrand cross-linking and cytotoxicity
Which of the following types of DNA alkylating agents is known to attack DNA via covalent modification?
Nitrogen mustards
Why are DNA crosslinking agents usually more effective than monoalkylators?
They form interstrand or intrastrand crosslinks
What is the mechanism of action for chlormethine, an aliphatic nitrogen mustard?
Anchimeric assistance from the nitrogen atom forming aziridinium cation
Which form of cancer is particularly rich in GC-sequences and susceptible to alkylating/crosslinking agents?
Burkitt's lymphoma
What was the effect of exposure to the chemical warfare agent sulphur mustard during the war?
Lowered white blood cell count
'Mustard gas' developed from war gas has a high chemical reactivity towards which biological molecules?
DNA nucleophilic centres
'Local extravasation usually causes tissue necrosis' refers to what specific compound used in chemotherapy regimens?
'Chlormethine'
'Attempts made to reduce side effects' of what compound due to its high reactivity and toxicity?
'Chlorambucil'
What is the primary approach used to reduce the reactivity of certain drugs before they reach their site of action?
Reducing the nucleophilic character of the tertiary nitrogen by attaching it to electron-withdrawing aromatic rings
What is the role of the P=O group in the structure of cyclophosphamide?
Decreases the electrophilicity of the nitrogen
What is the primary complication caused by acrolein, a potent electrophilic by-product of cyclophosphamide metabolism?
Hemorrhagic cystitis
Which agent is given as an adjuvant to protect the bladder and kidney during cyclophosphamide treatment?
Mesna
What are the two major metabolites produced by further enzymatic oxidation of aldophosphamide?
4-ketocyclophosphamide and carboxyphosphamide
What is the mechanism by which Mesna reacts with acrolein?
Michael addition
How do the active cross-linking agents produced by cyclophosphamide metabolism interfere with DNA processing?
By blocking DNA replication and transcription
What is the primary effect of alkylation by cyclophosphamide metabolites on DNA replication and RNA transcription?
Blocking of DNA replication and RNA transcription
What is the primary mechanism by which cyclophosphamide is activated in vivo?
Cytochrome P-450-dependent metabolic activation in the liver
What is the primary goal of attaching the tertiary nitrogen to electron-withdrawing aromatic rings in the design of certain drugs?
To decrease reactivity
Explore the structure of DNA and the use of nitrogen mustDNA alkylating agents in cancer chemotherapy. Learn about the mechanism of cytotoxicity for cisplatin, mitomycin C, triazenes, and nitrogen mustards through DNA alkylation, methylation, and complexation.
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