Identification of 4-anilino-3-quinolinecarbonitrile inhibitors of mitogen-activated protein/extracellular signal-regulated kinase 1 kinase.
A high-throughput screen for Ras-mitogen-activated protein kinase (MAPK) signaling inhibitors identified two series (class 1 and 2) of substituted 4-anilino-3-quinolinecarbonitriles as potent (IC(50)s <10 nmol/L) mitogen-activated protein/extracellular signal-regulated kinase 1 (MEK1) kinase inhibitors. These compounds had cyanoquinoline cores, but differed in their respective aniline groups [1a, 1b: 4-phenoxyphenylaniline; 2a, 2b: 3-chloro-4-(1-methylimidazol-2-sulfanyl)aniline]. These compounds were competitive inhibitors of ATP binding by MEK1 kinase, and they had minimal or no effect on Raf, epidermal growth factor receptor (EGFR), Akt, cyclin-dependent kinase 4 (CDK4), or MK2 kinases at concentrations >100-fold higher than those that inhibited MEK1 kinase. Both class 1 and 2 compounds inhibited in vitro growth of human tumor cell lines. A class 2 compound (2b) was the most potent inhibitor of human tumor cell growth in vitro, and this effect was linked to distinct suppression of MAPK phosphorylation in cells. Compound 2b did not affect phosphorylation status of other kinases, such as EGFR, Akt, and stress-activated protein (SAP)/c-jun-NH kinase (Jnk); nor did it affect overall tyrosine phosphorylation level in cells. However, compound 2b did inhibit MEK1 phosphorylation in cells. Inhibition of MEK1 phosphorylation by 2b was not due to a major effect on Raf kinase activity, because enzyme assays showed minimal Raf kinase inhibition. We believe compound 2b inhibits kinase activity upstream of Raf, and thereby affects MEK1 phosphorylation in cells. Even with the dual effect of 2b on MEK and MAPK phosphorylation, this compound was well tolerated and significantly inhibited growth of the human colon tumor cell line LoVo (at 50 and 100 mg/kg BID, i.p.) in a nude mouse xenograft model.
Mallon
Robert
R
Oncology Research, Wyeth Research, 401 N. Middletown Road, Pearl River, NY 10965, USA. mallonr@wyeth.com
Feldberg
Larry
L
Kim
Steven
S
Collins
Karen
K
Wojciechowicz
Donald
D
Kohler
Constance
C
Kovacs
Diana
D
Discafani
Carolyn
C
Zhang
Nan
N
Wu
Biqi
B
Floyd
Brawner
B
Powell
Dennis
D
Berger
Dan
D
D000255:Adenosine Triphosphate / Q000378:metabolism; D000814:Aniline Compounds / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D001665:Binding Sites; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D008819:Mice, Nude; D009570:Nitriles / Q000737:chemistry / Q000494:pharmacology; D019908:Proto-Oncogene Proteins c-raf / Q000037:antagonists & inhibitors / Q000378:metabolism; D011804:Quinolines / Q000737:chemistry / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship; D023041:Xenograft Model Antitumor Assays
D000814:Aniline Compounds; D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D009570:Nitriles; D011804:Quinolines; D000255:Adenosine Triphosphate; D019908:Proto-Oncogene Proteins c-raf; D048369:MAP Kinase Kinase 1