Induction of thrombospondin-1 partially mediates the anti-angiogenic activity of dexrazoxane

Abstract

Background:Considerable interest lies in the identification of novel anti-angiogenic compounds for cancer therapy. We have investigated whether dexrazoxane has anti-angiogenic properties and if so, the mechanism of the inhibition.Methods:The phenotypic effects of dexrazoxane on endothelial cell behaviour was investigated both in vitro using human umbilical vein endothelial cells (HUVECs) in cell proliferation, migration, cell cycle and aortic ring assays; and in vivo using the mouse angiogenesis subcutaneous sponge assay. Custom angiogenesis pathway microarrays were used to identify differentially expressed genes in endothelial cells after treatment with dexrazoxane vs a control. The differentially expressed genes were validated using real-time RT–PCR and western blotting; and the functional effect of one induced gene was confirmed using siRNA technology.Results:Treatment of endothelial cells with dexrazoxane resulted in a dose–response inhibition of cell growth lasting for up to 5 days after a single dose of the drug. Dexrazoxane was inhibitory in the aortic ring tube forming assay and strongly anti-angiogenic in vivo in the rodent subcutaneous sponge model. The anti-angiogenic effect in the sponge was seen after systemic injection into the tail vein as well as after direct injection of dexrazoxane into the sponge. Treatment of microvascular endothelial cells in vitro with subtoxic doses of dexrazoxane stimulated thrombospondin-1 (THBS-1) secretion. Knockdown of THBS-1 with siRNA removed the angiogenesis inhibition effect of dexrazoxane, which is consistent with the anti-angiogenic and vascular normalising properties of the drug being principally mediated by THBS-1.Conclusion:We show that dexrazoxane administered in small repeated doses is strongly anti-angiogenic and that this activity is mediated by induction of the anti-angiogenic THBS-1 in endothelial cells.

Cardioprotective effect of dexrazoxane in a rat model of myocardial infarction: Anti-apoptosis and promoting angiogenesis

“…Significantly, the neovascularization activity was further enhanced by DZR treatment. However, our results are not in direct agreement with a recent study of Maloney et al [27] who reported the inhibitory effect of DZR, mediated by induction of thrombospondin-1, on human umbilical vein endoethelial cells in vitro and the mouse angiogenesis subcutaneous sponge assay in vivo. In our model, MI damage might have triggered subsequent DZRinduced angiogenic activities.…”

Normalization of the Vasculature for Treatment of Cancer and Other Diseases

“…In addition, suramin therapy (an agent that binds to multiple receptors including EGF, TGF-β, and PDGF) enhanced homogeneity of vessel structure and tumor oxygenation in ectopic GBM xenografts (23). Other agents that normalize various aspects of tumor vessels include dexrazoxane (potentially through upregulation of TSP-1) (196), methylselenocysteine [possibly through downregulation of HIF-1α, inducible NOS (iNOS), and cyclooxygenase 2] (24, 25), and thalidomide (255). Thalidomide is now used clinically for multiple myeloma and may exert its anti-angiogenic effects by intercalating purine motifs into the promoter of bFGF.…”

Human papillomavirus E7 binds Oct4 and regulates its activity in HPV-associated cervical cancers

“…The iSCRIPT cDNA synthesis kit was used to synthesise 300ng of cDNA whereas KAPA Taq PCR was used for reverse transcription PCR (RT-PCR). The real time PCR was achieved by KAPA SYBR FAST qPCR Master Mix (2X) kit from Kapa Biosystems according to the manufacturers' guidelines and the primer sequences for performing both RT-PCR and Real-Time PCR are provided in S3 Table [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][70][71][72][73][74][75][76]. For each gene, the average C(t) value was determined and was normalised to housekeeping (GAPDH) mRNA levels.…”