Mode of action of DNA-competitive small molecule inhibitors of tyrosyl DNA phosphodiesterase 2.
Tyrosyl-DNA phosphodiesterase 2 (TDP2) is a 5'-tyrosyl DNA phosphodiesterase important for the repair of DNA adducts generated by non-productive (abortive) activity of topoisomerase II (TOP2). TDP2 facilitates therapeutic resistance to topoisomerase poisons, which are widely used in the treatment of a range of cancer types. Consequently, TDP2 is an interesting target for the development of small molecule inhibitors that could restore sensitivity to topoisomerase-directed therapies. Previous studies identified a class of deazaflavin-based molecules that showed inhibitory activity against TDP2 at therapeutically useful concentrations, but their mode of action was uncertain. We have confirmed that the deazaflavin series inhibits TDP2 enzyme activity in a fluorescence-based assay, suitable for high-throughput screen (HTS)-screening. We have gone on to determine crystal structures of these compounds bound to a 'humanized' form of murine TDP2. The structures reveal their novel mode of action as competitive ligands for the binding site of an incoming DNA substrate, and point the way to generating novel and potent inhibitors of TDP2.
Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, U.K. Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, U.K.
Peter
P
Hornyak
Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Falmer BN1 9QJ, U.K.
Trevor
T
Askwith
Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Falmer BN1 9QJ, U.K.
Sarah
S
Walker
Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, U.K.
Emilia
E
Komulainen
Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Falmer BN1 9QJ, U.K.
Michael
M
Paradowski
Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Falmer BN1 9QJ, U.K.
Lewis E
LE
Pennicott
Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, U.K.
Edward J
EJ
Bartlett
Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, U.K.
Nigel C
NC
Brissett
Drug Discovery Unit, Cancer Research UK Manchester Institute, University of Manchester, Manchester M20 4BX, U.K.
Ali
A
Raoof
Drug Discovery Unit, Cancer Research UK Manchester Institute, University of Manchester, Manchester M20 4BX, U.K.
Mandy
M
Watson
Drug Discovery Unit, Cancer Research UK Manchester Institute, University of Manchester, Manchester M20 4BX, U.K.
Allan M
AM
Jordan
Drug Discovery Unit, Cancer Research UK Manchester Institute, University of Manchester, Manchester M20 4BX, U.K.
Donald J
DJ
Ogilvie
Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Falmer BN1 9QJ, U.K.
Simon E
SE
Ward
Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Falmer BN1 9QJ, U.K.
John R
JR
Atack
Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, U.K. laurence.pearl@sussex.ac.uk k.w.caldecott@sussex.ac.uk antony.oliver@sussex.ac.uk.
Laurence H
LH
Pearl
Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, U.K. laurence.pearl@sussex.ac.uk k.w.caldecott@sussex.ac.uk antony.oliver@sussex.ac.uk.
Keith W
KW
Caldecott
Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, U.K. laurence.pearl@sussex.ac.uk k.w.caldecott@sussex.ac.uk antony.oliver@sussex.ac.uk.
Antony W
AW
Oliver
D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D051379:Mice; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012256:Riboflavin / Q000031:analogs & derivatives / Q000737:chemistry* / Q000494:pharmacology; D013696:Temperature
D010727:Phosphoric Diester Hydrolases; C122147:tyrosyl-DNA phosphodiesterase; D012256:Riboflavin
deoxyribonucleic acid (DNA) synthesis and repair; drug discovery and design; topoisomerases