9L gliosarcoma cell proliferation and tumor growth in rats are suppressed by N-hydroxy-N'-(4-butyl-2-methylphenol) formamidine (HET0016), a selective inhibitor of CYP4A.
The present study examined the effects of N-hydroxy-N'-(4-butyl-2 methylphenyl) formamidine (HET0016), a selective inhibitor of the formation of 20-hydroxyeicosatrienoic acid (20-HETE) on the growth of 9L rat gliosarcoma cells in vitro and in vivo. After 48 h of incubation, HET0016 reduced the proliferation of 9L in vitro by 55%, and this was associated with a fall in p42/p44 mitogen-activated protein kinase and stress-activated protein kinase/c-Jun NH(2)-terminal kinase phosphorylation and increased apoptosis. HET0016 inhibited epidermal growth factor (EGF) and platelet-derived growth factor (PDGF)-induced proliferation and diminished phosphorylation of PDGF receptors. A stable 20-HETE analog increased 9L cell proliferation. In vivo, chronic administration of HET0016 (10 mg/kg/day i.p.) for 2 weeks reduced the volume of 9L tumors by 80%. This was accompanied by a 4-fold reduction in the mitotic index, a 3- to 4-fold increase in the apoptotic index, and a approximately 50% decrease in vascularization in the tumor. HET0016 treatment increased mean survival time of the animals from 17 to 22 days. Liquid chromatography/mass spectrometry experiments indicated that neither 9L cells grown in vitro nor 9L tumors removed produce 20-HETE when incubated with arachidonic acid. The normal surrounding brain tissue, however, avidly makes 20-HETE, and this activity is selectively inhibited by HET0016. These results suggest that HET0016 may be the prototype of a class of antigrowth compounds that may be efficacious for treating malignant brain tumors. In vivo, it may act in part by inhibiting the formation of 20-HETE by the surrounding tissue. However, the antiproliferative effects of HET0016 on 9L cells in vitro seem unrelated to its ability to inhibit the formation of 20-HETE.
Guo
Meng
M
Eye Care Services, Henry Ford Hospital, Detroit, MI 48202-3450, USA. mguo1@hfhs.org
Roman
Richard J
RJ
Fenstermacher
Joseph D
JD
Brown
Stephen L
SL
Falck
John R
JR
Arbab
Ali S
AS
Edwards
Paul A
PA
Scicli
A Guillermo
AG
D000578:Amidines / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D016718:Arachidonic Acid / Q000378:metabolism; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002540:Cerebral Cortex / Q000473:pathology; D042926:Cytochrome P-450 CYP4A / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D018316:Gliosarcoma / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D009368:Neoplasm Transplantation; D051381:Rats; D011916:Rats, Inbred F344
D000578:Amidines; D004791:Enzyme Inhibitors; C000708209:HET0016; D016718:Arachidonic Acid; D042926:Cytochrome P-450 CYP4A