We have previously reported that 8-epipuupehedione, a synthetic derivative of sesquiterpenes found in several kinds of sponges, is a potent inhibitor of angiogenesis. Here, we show that 8-epipuupehedione is also a potent anti- leukaemic compound, targeting three hallmarks of malignancy: proliferation, survival and extra-cellular matrix re-modelling. To fulfil this goal, we use the HL-60 promyeolocytic cells as our model system and the following experimental procedures: cell growth assay, Hoetsch staining, cell cycle analysis and DNA fragmentation, caspase 3 activity and zymographic assays. Our results show that this compound inhibits proliferation and has potent and specific pro-apoptotic effects on HL-60 promyelocytic cells, inducing their nuclei and DNA fragmentation, as well as caspase 3 activity activation. Furthermore, 8-epipuupehedione strongly inhibits matrix metalloproteinase-2 and urokinase production by HL-60 cells. These results suggest that 8-epipuupehedione could be an attractive drug for further evaluation in the treatment of leukemia.

The ditriazine derivative DTD (4,10-dichloropyrido[5,6:4,5]thieno[3,2-d':3,2-d]-1,2,3-ditriazine) has been previously reported to reduce the degree of granulomatous inflammation and vascular density in a murine air pouch granuloma model. The aim of this study was to test whether DTD affects angiogenesis. Our results show that DTD inhibits in vivo angiogenesis in the chorioallantoic membrane (CAM) assay at doses equal or lower than 0.3 nmol/egg. Different in vitro assays were used to study the potential effects of this compound on key steps of angiogenesis, namely, a colorimetric assay of cell proliferation/viability, a morphogenesis on Matrigel assay, zymographic assays for gelatinases and nuclear morphology and cell cycle analysis for apoptosis induction. Our data indicate that DTD inhibits proliferation but does not induce apoptosis in endothelial cells in vitro. DTD suppresses the endothelial capillary-like chord formation at concentrations lower than those required to inhibit proliferation. DTD treatment inhibits the matrix metalloproteinase-2 production in endothelial and fibrosarcoma cells, but does not affect the cyclooxygenase-2 expression in endothelial cells, as assessed by western blot analysis. Taken together, results here presented indicate that DTD exhibits an anti-angiogenic activity that is independent of inflammatory processes and make it a promising drug for further evaluation in the treatment of angiogenesis-related pathologies.