Abstract
Background: DNA topoisomerases are key enzymes that modulate the topological state of DNA through the breaking and rejoining of DNA strands. Human topoisomerase I belongs to the family of poly(ADP-ribose)-binding proteins and is the target of camptothecin derived anticancer drugs. Poly(ADP-ribosyl)ation occurs at specific sites of the enzyme inhibiting the cleavage and enhancing the religation steps during the catalytic cycle. Thus, ADP-ribose polymers antagonize the activity of topoisomerase I poisons, whereas PARP inhibitors increase their antitumor effects. Methods: Using site-directed mutagenesis we have analyzed the interaction of human topoisomerase I and poly (ADP-ribose) through enzymatic activity and binding procedures. Results: Mutations of the human topoisomerase I hydrophobic or charged residues, located on the putative polymer binding sites, are not sufficient to abolish or reduce the binding of the poly(ADP-ribose) to the protein. These results suggest either the presence of additional binding sites or that the mutations are not enough perturbative to destroy the poly(ADP-ribose) interaction, although in one mutant they fully abolish the enzyme activity. Conclusions: It can be concluded that mutations at the hydrophobic or charged residues of the putative polymer binding sites do not interfere with the ability of poly(ADP-ribose) to antagonize the antitumor activity of topoisomerase I poisons.
| Original language | English |
|---|---|
| Article number | 71 |
| Journal | Journal of Experimental and Clinical Cancer Research |
| Volume | 33 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2014 |
Fingerprint
Keywords
- Camptothecin
- Cleavage
- PARP inhibitors
- PARylation
- Religation rate
- Topoisomerase I
ASJC Scopus subject areas
- Cancer Research
- Oncology
Cite this
Mutations of human DNA topoisomerase I at poly (ADP-ribose) binding sites : Modulation of camptothecin activity by ADP-ribose polymers. / Tesauro, Cinzia; Graziani, Grazia; Arnò, Barbara; Zuccaro, Laura; Muzi, Alessia; D'Annessa, Ilda; Santori, Elettra; Tentori, Lucio; Leonetti, Carlo; Fiorani, Paola; Desideri, Alessandro.
In: Journal of Experimental and Clinical Cancer Research, Vol. 33, No. 1, 71, 2014.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mutations of human DNA topoisomerase I at poly (ADP-ribose) binding sites
T2 - Modulation of camptothecin activity by ADP-ribose polymers
AU - Tesauro, Cinzia
AU - Graziani, Grazia
AU - Arnò, Barbara
AU - Zuccaro, Laura
AU - Muzi, Alessia
AU - D'Annessa, Ilda
AU - Santori, Elettra
AU - Tentori, Lucio
AU - Leonetti, Carlo
AU - Fiorani, Paola
AU - Desideri, Alessandro
PY - 2014
Y1 - 2014
N2 - Background: DNA topoisomerases are key enzymes that modulate the topological state of DNA through the breaking and rejoining of DNA strands. Human topoisomerase I belongs to the family of poly(ADP-ribose)-binding proteins and is the target of camptothecin derived anticancer drugs. Poly(ADP-ribosyl)ation occurs at specific sites of the enzyme inhibiting the cleavage and enhancing the religation steps during the catalytic cycle. Thus, ADP-ribose polymers antagonize the activity of topoisomerase I poisons, whereas PARP inhibitors increase their antitumor effects. Methods: Using site-directed mutagenesis we have analyzed the interaction of human topoisomerase I and poly (ADP-ribose) through enzymatic activity and binding procedures. Results: Mutations of the human topoisomerase I hydrophobic or charged residues, located on the putative polymer binding sites, are not sufficient to abolish or reduce the binding of the poly(ADP-ribose) to the protein. These results suggest either the presence of additional binding sites or that the mutations are not enough perturbative to destroy the poly(ADP-ribose) interaction, although in one mutant they fully abolish the enzyme activity. Conclusions: It can be concluded that mutations at the hydrophobic or charged residues of the putative polymer binding sites do not interfere with the ability of poly(ADP-ribose) to antagonize the antitumor activity of topoisomerase I poisons.
AB - Background: DNA topoisomerases are key enzymes that modulate the topological state of DNA through the breaking and rejoining of DNA strands. Human topoisomerase I belongs to the family of poly(ADP-ribose)-binding proteins and is the target of camptothecin derived anticancer drugs. Poly(ADP-ribosyl)ation occurs at specific sites of the enzyme inhibiting the cleavage and enhancing the religation steps during the catalytic cycle. Thus, ADP-ribose polymers antagonize the activity of topoisomerase I poisons, whereas PARP inhibitors increase their antitumor effects. Methods: Using site-directed mutagenesis we have analyzed the interaction of human topoisomerase I and poly (ADP-ribose) through enzymatic activity and binding procedures. Results: Mutations of the human topoisomerase I hydrophobic or charged residues, located on the putative polymer binding sites, are not sufficient to abolish or reduce the binding of the poly(ADP-ribose) to the protein. These results suggest either the presence of additional binding sites or that the mutations are not enough perturbative to destroy the poly(ADP-ribose) interaction, although in one mutant they fully abolish the enzyme activity. Conclusions: It can be concluded that mutations at the hydrophobic or charged residues of the putative polymer binding sites do not interfere with the ability of poly(ADP-ribose) to antagonize the antitumor activity of topoisomerase I poisons.
KW - Camptothecin
KW - Cleavage
KW - PARP inhibitors
KW - PARylation
KW - Religation rate
KW - Topoisomerase I
UR - http://www.scopus.com/inward/record.url?scp=84908213301&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84908213301&partnerID=8YFLogxK
U2 - 10.1186/s13046-014-0071-z
DO - 10.1186/s13046-014-0071-z
M3 - Article
C2 - 25227992
AN - SCOPUS:84908213301
VL - 33
JO - Journal of Experimental and Clinical Cancer Research
JF - Journal of Experimental and Clinical Cancer Research
SN - 0392-9078
IS - 1
M1 - 71
ER -