Etoposide-TopIIα Binding Interactions Quiz

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What nucleophiles can the aziridinium ion react with?

SH, OH, and NH groups only

Water only

DNA only

Unpaired DNA and/or cell nucleophiles such as SH, OH, and NH groups (correct)

How does an aromatic nitrogen substituent R, like phenyl, stabilize the aziridinium ion?

By forming inactive dehalogenated diol

By destabilizing the lone pair of electrons

Through resonance and stabilizing the lone pair of electrons (correct)

By increasing its reactivity

How does resonance delocalization affect the rate of intramolecular nucleophilic attack?

It significantly slows the rate (correct)

It stops the reaction completely

It has no impact on the rate

It accelerates the rate

What can act as nucleophiles to advance the degradative process in aqueous media?

Both mustard nitrogen and oxygen of water Signup and view all the answers

How can the decomposition reactions of nitrogen mustards be inhibited?

By protonation to eliminate nucleophilic character Signup and view all the answers

Which factor helps enhance stability in aqueous solution for nitrogen mustards?

Acidic pH (e.g., 3-5) Signup and view all the answers

What is a characteristic feature of Chlorambucil among aromatic nitrogen mustards?

Resonance-stabilized amine structure Signup and view all the answers

Which phase of the cell cycle do epipodophyllotoxins have the most devastating impact on?

S phase Signup and view all the answers

What is a common mechanism of resistance to epipodophyllotoxins?

Enhanced DNA repair mechanisms Signup and view all the answers

How is a water-soluble phosphate ester analogue of etoposide administered?

In aqueous vehicles Signup and view all the answers

What is the major metabolite generated by lactone hydrolysis of etoposide and teniposide?

Inactive hydroxy acid Signup and view all the answers

Which enzyme catalyzes the O-demethylation of epipodophyllotoxins?

CYP3A4 Signup and view all the answers

What is the purpose of glucuronide or sulfate conjugation in the metabolism of epipodophyllotoxins?

Inactivation and excretion of metabolites Signup and view all the answers

What is an isoform where etoposide was found in a ternary complex according to the text?

TopIIβ Signup and view all the answers

How is the area that binds the glycoside moiety of epipodophyllotoxins described according to the text?

Unhindered Signup and view all the answers

Which protein mediates compromised carrier-mediated cellular transport of cisplatin?

CTR1 Signup and view all the answers

What is one of the mechanisms of resistance to cisplatin therapy mentioned in the text?

Uncontrolled expression of noncoding RNA (lncRNA) Signup and view all the answers

Which proteins are responsible for cellular efflux in cisplatin-resistant tumors?

P-type ATP 7A/7B and multidrug resistance proteins Signup and view all the answers

What cellular process can lead to increased DNA repair and/or tolerance to cisplatin-induced DNA damage?

Uncontrolled expression of noncoding RNA (lncRNA) Signup and view all the answers

Which repair proteins remove platinum-damaged segments from DNA in cisplatin-resistant tumors?

Mismatch repair proteins Signup and view all the answers

What interaction reduces the number of drug-DNA adducts when amifostine is activated?

Interaction with cisplatin Signup and view all the answers

Which mechanism contributes to acquired resistance after multiple courses of cisplatin therapy in ovarian cancer?

Uncontrolled expression of noncoding RNA (lncRNA) Signup and view all the answers

What is a mechanism that leads to enhanced intracellular inactivation of cisplatin?

Vesicle drug trapping Signup and view all the answers

What is the mechanism for testosterone reduction to DHT?

Hydrogen transfer from NADPH to the 5α-position of testosterone Signup and view all the answers

Which enzyme is responsible for the conversion of testosterone into DHT?

5α-reductase Signup and view all the answers

What are finasteride and dutasteride known as?

5α-reductase inhibitors Signup and view all the answers

Which inhibitor is a selective inhibitor of 5AR2?

Finasteride Signup and view all the answers

What happens when 5AR2 is inhibited with finasteride or dutasteride?

Decreases in plasma and intraprostatic DHT concentrations Signup and view all the answers

What do finasteride and dutasteride have the ability to do, besides being competitive inhibitors of 5α-reductase?

Inactivate 5AR through irreversible modification of the enzyme Signup and view all the answers

What does the inhibition constant (IC50) for finasteride suggest?

Finasteride is more potent as an inhibitor of 5AR2 than 5AR1 Signup and view all the answers

How do finasteride and dutasteride mimic the pathway of testosterone reduction to 5α-dihydrotestosterone?

By binding to the same site on 5α-reductase where testosterone binds Signup and view all the answers

What is the primary metabolic pathway of finasteride in the liver?

Formation of a monocarboxylic acid from monohydroxylation of the t-butyl side chain Signup and view all the answers

What role do lipophilic groups at the 17β position play in improving the biological activity of finasteride?

Improving its biological activity Signup and view all the answers

How does finasteride's mechanism-based inhibition explain its potency and specificity in treating benign prostatic hyperplasia?

By forming an enzyme-bound dihydrofinasteride-NADP adduct Signup and view all the answers

What does dutasteride's inhibition of 5AR2 compared to 5AR1 imply?

Dutasteride is less potent as an inhibitor of 5AR2 than 5AR1 Signup and view all the answers

What prevents enol tautomerization to a keto group in finasteride?

4-aza functional group Signup and view all the answers

What is formed when finasteride accepts a H- transfer from NADPH to the 1α-position of its A-ring?

$\text{Enol intermediate}$ Signup and view all the answers

Etoposide-TopIIα Binding Interactions Quiz

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Questions and Answers

What nucleophiles can the aziridinium ion react with?

How does an aromatic nitrogen substituent R, like phenyl, stabilize the aziridinium ion?

How does resonance delocalization affect the rate of intramolecular nucleophilic attack?

What can act as nucleophiles to advance the degradative process in aqueous media?

How can the decomposition reactions of nitrogen mustards be inhibited?

Which factor helps enhance stability in aqueous solution for nitrogen mustards?

What is a characteristic feature of Chlorambucil among aromatic nitrogen mustards?

Which phase of the cell cycle do epipodophyllotoxins have the most devastating impact on?

What is a common mechanism of resistance to epipodophyllotoxins?

How is a water-soluble phosphate ester analogue of etoposide administered?

What is the major metabolite generated by lactone hydrolysis of etoposide and teniposide?

Which enzyme catalyzes the O-demethylation of epipodophyllotoxins?

What is the purpose of glucuronide or sulfate conjugation in the metabolism of epipodophyllotoxins?

What is an isoform where etoposide was found in a ternary complex according to the text?

How is the area that binds the glycoside moiety of epipodophyllotoxins described according to the text?

Which protein mediates compromised carrier-mediated cellular transport of cisplatin?

What is one of the mechanisms of resistance to cisplatin therapy mentioned in the text?

Which proteins are responsible for cellular efflux in cisplatin-resistant tumors?

What cellular process can lead to increased DNA repair and/or tolerance to cisplatin-induced DNA damage?

Which repair proteins remove platinum-damaged segments from DNA in cisplatin-resistant tumors?

What interaction reduces the number of drug-DNA adducts when amifostine is activated?

Which mechanism contributes to acquired resistance after multiple courses of cisplatin therapy in ovarian cancer?

What is a mechanism that leads to enhanced intracellular inactivation of cisplatin?

What is the mechanism for testosterone reduction to DHT?

Which enzyme is responsible for the conversion of testosterone into DHT?

What are finasteride and dutasteride known as?

Which inhibitor is a selective inhibitor of 5AR2?

What happens when 5AR2 is inhibited with finasteride or dutasteride?

What do finasteride and dutasteride have the ability to do, besides being competitive inhibitors of 5α-reductase?

What does the inhibition constant (IC50) for finasteride suggest?

How do finasteride and dutasteride mimic the pathway of testosterone reduction to 5α-dihydrotestosterone?

What is the primary metabolic pathway of finasteride in the liver?

What role do lipophilic groups at the 17β position play in improving the biological activity of finasteride?

How does finasteride's mechanism-based inhibition explain its potency and specificity in treating benign prostatic hyperplasia?

What does dutasteride's inhibition of 5AR2 compared to 5AR1 imply?

What prevents enol tautomerization to a keto group in finasteride?

What is formed when finasteride accepts a H- transfer from NADPH to the 1α-position of its A-ring?

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