Induction of reactive oxygen intermediates-dependent programmed cell death in human malignant ex vivo glioma cells and inhibition of the vascular endothelial growth factor production by taurolidine.
OBJECTIVE
Taurolidine, a derivative of the amino acid taurin, was recently found to display a potent antineoplastic effect both in vitro and in vivo. The authors therefore initiated studies to assess the potential antineoplastic activity of taurolidine in human glioma cell lines and in ex vivo malignant cell cultures. They also studied the mechanisms that induce cell death and the impact of taurolidine on tumor-derived vascular endothelial growth factor (VEGF) production.


METHODS
Cytotoxicity and clonogenic assays were performed using crystal violet staining. In the cytotoxicity assay 100% of glioma cell lines (eight of eight) and 74% of ex vivo glioma cultures (14 of 19) demonstrated sensitivity to taurolidine, with a mean median effective concentration (EC50) of 51 +/- 28 microg/ml and 56 +/- 23 microg/ml, respectively. Colony formation was inhibited by taurolidine, with a mean EC50 of 7 +/- 3 microg/ml for the cell lines and a mean EC50 of 3.5 +/- 1.7 microg/ml for the ex vivo glioma cultures. On observing this high activity of taurolidine in both assays, the authors decided to evaluate its cell death mechanisms. Fragmentation of DNA, externalization of phosphatidylserine, activation of poly(adenosine diphosphate-ribose) polymerase, loss of the mitochondrial membrane potential followed by a release of apoptosis-inducing factor, and typical apoptotic features were found after taurolidine treatment. Cell death was preceded by the generation of reactive O2 intermediates, which was abrogated by N-acetylcysteine but not by benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Moreover, taurolidine also induced suppression of VEGF production on the protein and messenger RNA level, as shown by an enzyme-linked immunosorbent assay and by reverse transcription-polymerase chain reaction.


CONCLUSIONS
Given all these findings, taurolidine may be a promising new agent in the treatment of malignant gliomas; it displays a combination of antineoplastic and antiangiogenic activities, inducing tumor cell apoptosis and inhibiting tumor-derived VEGF production.
Rodak
Roksana
R
Department of Neurosurgery, University Hospital Zurich, Switzerland.
Kubota
Hisashi
H
Ishihara
Hideyuki
H
Eugster
Hans-Pietro
HP
Könü
Dilek
D
Möhler
Hanns
H
Yonekawa
Yasuhiro
Y
Frei
Karl
K
D000111:Acetylcysteine / Q000494:pharmacology; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001932:Brain Neoplasms; D061945:Caspase Inhibitors; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D024161:Collagen Type XI / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D053222:Fas Ligand Protein; D015870:Gene Expression / Q000187:drug effects; D005910:Glioma; D006801:Humans; D008562:Membrane Glycoproteins / Q000494:pharmacology; D008928:Mitochondria / Q000502:physiology; D010718:Phosphatidylserines / Q000378:metabolism; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D017382:Reactive Oxygen Species / Q000378:metabolism; D013654:Taurine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D013829:Thiadiazines / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors* / Q000235:genetics
D000590:Amino Acid Chloromethyl Ketones; D000970:Antineoplastic Agents; C499319:COL11A2 protein, human; D061945:Caspase Inhibitors; D024161:Collagen Type XI; D015853:Cysteine Proteinase Inhibitors; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D010718:Phosphatidylserines; D017382:Reactive Oxygen Species; D013829:Thiadiazines; D042461:Vascular Endothelial Growth Factor A; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D013654:Taurine; C012566:taurolidine; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D000111:Acetylcysteine