Chemsitry E-Learning package; Anthracyclines and Cytotoxic antibiotics

Question 1

What kind of anti-cancer drugs are doxirubicin and duanomycin?

Answer 1

Anthracyclines and other cytotoxic antibiotics

Question 2

How do they interact with DNA and how does this differ to alkylating agents?

Answer 2

Alkylating agents covalently bond to the bases in DNA whereas the anthracyclines do not bond covalently. Rather they intercalate in between successive bases

Question 3

What is the cyctotoxic effect of anthracyclines such as doxirubicin and duanomycin?

Answer 3

Not the intercalation
The antrhacyclines inhibit the final step that topoisomerase II facilitates, therefore the cut DNA cannot undergo religation

Question 4

What is the role of the topoisomerase enzymes in DNA regulation?

Answer 4

When DNA polymerase starts to unravel the helix strands, the tension in the rest of the helix builds. TP I cuts one of the strands in order to relieve the tension, TP II cuts both strands and relieves two turns of tension, then religases the strands