Antiangiogenic and antiproliferative effects of substituted-1,3,4-oxadiazole derivatives is mediated by down regulation of VEGF and inhibition of translocation of HIF-1alpha in Ehrlich ascites tumor cells.
OBJECTIVE
1,3,4-Oxadiazoles are an important class of heterocyclic compounds, which play a pivotal role in various pharmaceutical applications. Here, we investigated the antiangiogenic and antiproliferative effects of the derivatives and explored its mechanism of action on EAT cells.


METHODS
The cytotoxic effect of the derivatives on EAT and HEK293 cells was assessed by MTT assay. Effect of the derivatives on ALP activity and proliferation was measured. Swiss albino mice transplanted with EAT cells were used as a model system to study the effect of the derivatives in vivo. Inhibition of angiogenesis in mice peritoneum, CAM and Cornea of the rat were studied. Finally, the effects on VEGF gene expression, HIF-1alpha translocation and cell cycle arrest were determined.


RESULTS
The IC50 range for growth inhibition of EAT cells was found to be 140-175 microM. In contrast normal HEK293 cells were resistant to the derivatives at this range. Treatment with derivatives in vivo was demonstrated by the down regulation of VEGF in EAT cells and inhibition of blood vessels formation in mice peritoneum, CAM and cornea of rat, indicating the potent angioinhibitory effect of the derivatives. VEGF promoter-luciferase reporter gene expression analysis showed suppression of VEGF gene expression in vitro. The derivatives proved to be potent antiproliferative agents as shown by FACS analysis and decreased ALP activity. Furthermore, expression of HIF-1alpha was also down regulated by derivatives by repressing its nuclear translocation.


CONCLUSIONS
Oxadiazole derivatives are strong bioactive compounds with antiangiogenic and antiproliferative potential both in vitro and in vivo. We postulate that diminished HIF-1alpha nuclear presence in oxadiazole treated EAT cells could be responsible for decreased VEGF expression and antiangiogenic effects.
Department of Studies in Biotechnology, University of Mysore, Manasagangotri, Mysore 570006, Karnataka, India.
Akhilesh
A
Kumar
Saritha S
SS
D'Souza
Sachin Raj Mysore
SR
Nagaraj
S L
SL
Gaonkar
Bharathi P
BP
Salimath
K M Lokanatha
KM
Rai
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001202:Ascitic Fluid / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D001835:Body Weight / Q000187:drug effects; D002286:Carcinoma, Ehrlich Tumor / Q000188:drug therapy* / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000098:blood supply / Q000187:drug effects; D016510:Corneal Neovascularization / Q000188:drug therapy / Q000473:pathology; D015536:Down-Regulation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D020128:Inhibitory Concentration 50; D051379:Mice; D015394:Molecular Structure; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000473:pathology; D010069:Oxadiazoles / Q000494:pharmacology* / Q000627:therapeutic use; D010537:Peritoneum / Q000098:blood supply / Q000473:pathology; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D015996:Survival Rate; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010069:Oxadiazoles; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D000469:Alkaline Phosphatase