Synthesis and structure-activity relationships of N-6 substituted analogues of 9-hydroxy-4-phenylpyrrolo[3,4-c]carbazole-1,3(2H,6H)-diones as inhibitors of Wee1 and Chk1 checkpoint kinases.
A series of N-6 substituted 9-hydroxy-4-phenylpyrrolo[3,4-c]carbazole-1,3(2H,6H)-diones were prepared from N-substituted (5-methoxyphenyl)ethenylindoles. The target compounds were tested for their ability to inhibit the G2/M cell cycle checkpoint kinases, Wee1 and Chk1. Analogues with neutral or cationic N-6 side chains were potent dual inhibitors. Acidic side chains provided potent (average IC(50) 0.057 microM) and selective (average ratio 223-fold) Wee1 inhibition. Co-crystal structures of inhibitors bound to Wee1 show that the pyrrolo[3,4-c]carbazole scaffold binds in the ATP-binding site, with N-6 substituents involved in H-bonding to conserved water molecules. HT-29 cells treated with doxorubicin and then target compounds demonstrate an active Cdc2/cyclin B complex, inhibition of the doxorubicin-induced phosphorylation of tyrosine 15 of Cdc2 and abrogation of the G2 checkpoint.
Smaill
Jeff B
JB
Auckland Cancer Society Research Centre, School of Medical Sciences, The University of Auckland, Private Bag 92019, Auckland 1020, New Zealand. j.smaill@auckland.ac.nz
Baker
Edward N
EN
Booth
R John
RJ
Bridges
Alexander J
AJ
Dickson
James M
JM
Dobrusin
Ellen M
EM
Ivanovic
Ivan
I
Kraker
Alan J
AJ
Lee
Ho H
HH
Lunney
Elizabeth A
EA
Ortwine
Daniel F
DF
Palmer
Brian D
BD
Quin
John
J
Squire
Christopher J
CJ
Thompson
Andrew M
AM
Denny
William A
WA
D002227:Carbazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors*; D019073:HT29 Cells; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors*; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship
D002227:Carbazoles; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human