Resveratrol acts as a topoisomerase II poison in human glioma cells

Abstract

Recently, we demonstrated that Resveratrol (RSV), a well known natural stilbene, is able to induce a delay in S progression with a concomitant increase in cH2AX expression in U87 glioma cells. Furthermore, we showed that it inhibits the ability of recombinant human topoisomerase IIa to decatenate kDNA in vitro. Because proliferating tumor cells express topoisomerases at high levels and these enzymes are important targets of some of the most successful anticancer drugs, we tested whether RSV is able to poison topoisomerase IIa in glioma cells. Then, we monitored the increase of micronuclei in RSV treated U87 cells as a consequence of the conversion of TOPOII/DNA cleavable complexes to permanent DNA damage. Finally, we assayed the ability of RSV in modulating the expression of target proteins involved in DNA damage signalling, namely ATR, ATM, Chk1, Chk2 and cH2AX. Through a molecular modelling here we show that RSV binds at the TOPOII/DNA interface thus establishing several hydrogen bonds. Moreover, we show that RSV poisons TOPOIIa so inducing DNA damage; ATM, Chk2 and cH2AX are involved in the DNA damage signalling after RSV treatment.Resveratrol (3,4 0 ,5-trihydroxylstilbene), a polyphenol synthesized by a wide variety of plant species, is well known for its antitumor potential as demonstrated by many in vitro studies. 1 Nevertheless, the molecular targets of Resveratrol (RSV) activity seem not yet completely understood due to the multiplicity of RSV treatment effects in normal and transformed cultured cells. However, it is well known that RSV can disturb the normal progress of the cell cycle so decreasing the proliferation and can also induce apoptosis in cell type-and concentration-dependent mode. 2 On the other hand RSV, such as many other natural polyphenols, acts as antioxidant or prooxidant due to the intracellular presence of transition metal ions. The prooxidant activity could be an important action mechanism for its anticancer properties. 3 It has been suggested that some of the cellular effects of polyphenols, such as anti-proliferative and proapoptotic actions, could be correlated with their ability to act on topoisomerases. 4,5 These are ubiquitous nuclear enzymes that modulate the topological state of DNA by breaking and resealing one or both strands of a DNA duplex. In eukaryotic cells, type II topoisomerases, isoforms a and b, function during major cellular processes involving DNA (recombination, replication, proper chromosome structure and segregation) generating intermediate cleavable or covalent complexes with a short half-life. 6 Highly proliferating tumor cells express these enzymes, particularly Type IIa, at levels many times higher than quiescent cells 7,8 so that topoisomerases II are important targets for some of the anticancer drugs most successfully used in the treatment of human malignancies. TOPOII-targeted agents interfere with the binding between DNA and TOPOII or act by increasing the concentration of topoisomerase-DNA covalent complexes. These agents shifting the equilibrium of t...

Classical and atypical resistance of cancer cells as a target for resveratrol

“…It is known that in glioblastoma U87 cell line resveratrol may unspecifically interact both with DNA and TopoII, which was shown with the use of molecular docking mechanisms. In the cells expressing topoisomerases on normal or increased level resveratrol attaches to the cleavable TopoII-DNA complex thus forming a network of hydrogen bonds and causing its stabilisation (43), thus, it acts similarly to cytostatics. Moreover, its effect on the activity of TopoIIα was confirmed, which results in the loss of capability to disentangle and remove DNA knots and supercoils.…”

Biological significance and therapeutic implication of resveratrol-inhibited Wnt, Notch and STAT3 signaling in cervical cancer cells

“…Resveratrol (3, 5, 4′-trihydroxy-trans-stilbene), a phytoalexin, can be found in some edible food materials such as grape skins, pea-nuts and red wine [7,8]. A body of evidence shows that this compound has multiple biological activities including induction of differentiation and apoptosis of cancer cells [9,10].…”

Resveratrol: A novel type of topoisomerase II inhibitor

“…Based on increased DNA damage and cell-cycle delay following treatment in mammalian cells, resveratrol has been claimed to act as a topo II poison (22,37,38). Additionally, resveratrol has been shown to inhibit topo II decatenation activity in vitro (22,38).…”