Modulation of angiogenesis by dithiolethione-modified NSAIDs and valproic acid.
OBJECTIVE
Angiogenesis involves multiple signaling pathways that must be considered when developing agents to modulate pathological angiogenesis. Because both cyclooxygenase inhibitors and dithioles have demonstrated anti-angiogenic properties, we investigated the activities of a new class of anti-inflammatory drugs containing dithiolethione moieties (S-NSAIDs) and S-valproate.


METHODS
Anti-angiogenic activities of S-NSAIDS, S-valproate, and the respective parent compounds were assessed using umbilical vein endothelial cells, muscle and tumor tissue explant angiogenesis assays, and developmental angiogenesis in Fli:EGFP transgenic zebrafish embryos.


RESULTS
Dithiolethione derivatives of diclofenac, valproate, and sulindac inhibited endothelial cell proliferation and induced Ser(78) phosphorylation of hsp27, a known molecular target of anti-angiogenic signaling. The parent drugs lacked this activity, but dithiolethiones were active at comparable concentrations. Although dithiolethiones can potentially release hydrogen sulphide, NaSH did not reproduce some activities of the S-NSAIDs, indicating that the dithioles regulate angiogenesis through mechanisms other than release of H(2)S. In contrast to the parent drugs, S-NSAIDs, S-valproate, NaSH, and dithiolethiones were potent inhibitors of angiogenic responses in muscle and HT29 tumor explants assessed by 3-dimensional collagen matrix assays. Dithiolethiones and valproic acid were also potent inhibitors of developmental angiogenesis in zebrafish embryos, but the S-NSAIDs, remarkably, lacked this activity.


CONCLUSIONS
S-NSAIDs and S-valproate have potent anti-angiogenic activities mediated by their dithiole moieties. The novel properties of S-NSAIDs and S-valproate to inhibit pathological versus developmental angiogenesis suggest that these agents may have a role in cancer treatment.
Isenberg
J S
JS
Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1500, USA.
Jia
Y
Y
Field
L
L
Ridnour
L A
LA
Sparatore
A
A
Del Soldato
P
P
Sowers
A L
AL
Yeh
G C
GC
Moody
T W
TW
Wink
D A
DA
Ramchandran
R
R
Roberts
D D
DD
D000781:Anethole Trithione / Q000494:pharmacology*; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D010766:Phosphorylation; D012995:Solubility; D014635:Valproic Acid / Q000494:pharmacology*; D015027:Zebrafish
D020533:Angiogenesis Inhibitors; D000894:Anti-Inflammatory Agents, Non-Steroidal; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486699:Hspb2 protein, mouse; D014635:Valproic Acid; D000781:Anethole Trithione