High-affinity inhibitors of human NAD-dependent 15-hydroxyprostaglandin dehydrogenase: mechanisms of inhibition and structure-activity relationships.
BACKGROUND
15-Hydroxyprostaglandin dehydrogenase (15-PGDH, EC 1.1.1.141) is the key enzyme for the inactivation of prostaglandins, regulating processes such as inflammation or proliferation. The anabolic pathways of prostaglandins, especially with respect to regulation of the cyclooxygenase (COX) enzymes have been studied in detail; however, little is known about downstream events including functional interaction of prostaglandin-processing and -metabolizing enzymes. High-affinity probes for 15-PGDH will, therefore, represent important tools for further studies.


RESULTS
To identify novel high-affinity inhibitors of 15-PGDH we performed a quantitative high-throughput screen (qHTS) by testing >160 thousand compounds in a concentration-response format and identified compounds that act as noncompetitive inhibitors as well as a competitive inhibitor, with nanomolar affinity. Both types of inhibitors caused strong thermal stabilization of the enzyme, with cofactor dependencies correlating with their mechanism of action. We solved the structure of human 15-PGDH and explored the binding modes of the inhibitors to the enzyme in silico. We found binding modes that are consistent with the observed mechanisms of action.


CONCLUSIONS
Low cross-reactivity in screens of over 320 targets, including three other human dehydrogenases/reductases, suggest selectivity of the present inhibitors for 15-PGDH. The high potencies and different mechanisms of action of these chemotypes make them a useful set of complementary chemical probes for functional studies of prostaglandin-signaling pathways.


BACKGROUND
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Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.
Frank H
FH
Niesen
Lena
L
Schultz
Ajit
A
Jadhav
Chitra
C
Bhatia
Kunde
K
Guo
David J
DJ
Maloney
Ewa S
ES
Pilka
Minghua
M
Wang
Udo
U
Oppermann
Tom D
TD
Heightman
Anton
A
Simeonov
D001665:Binding Sites; D001667:Binding, Competitive; D055162:Biocatalysis / Q000187:drug effects; D018360:Crystallography, X-Ray; D015232:Dinoprostone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D009243:NAD / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D011485:Protein Binding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D009243:NAD; D006911:Hydroxyprostaglandin Dehydrogenases; C035859:15-hydroxyprostaglandin dehydrogenase; D015232:Dinoprostone