A new development of triterpene acid-containing extracts from Viscum album L. displays synergistic induction of apoptosis in acute lymphoblastic leukaemia.
OBJECTIVE
Aqueous Viscum album L. extracts are widely used for anti-cancer therapies. Due to their low solubility, triterpenes (which are known to act on cancers), do not occur in aqueous extracts in significant amounts. Using cyclodextrins, we have found it possible to solubilize mistletoe triterpene acids and to determine their effects on acute lymphoblastic leukaemia (ALL) in vitro and in vivo.


METHODS
A C.B-17/SCID model of pre-B ALL (NALM-6) was used to test efficacy and mechanisms of treatment with lectin- and triterpene acid containing preparations in vivo. Cytotoxicity of increasing concentrations of V. album L. preparations was assessed in vitro. Apoptosis was determined using mitochondrial membrane potential measurements, annexin V/PI, western blot analyses and caspase inhibitor assays.


RESULTS
Solubilized triterpene acid- or lectin-containing V. album L. extracts inhibited cell proliferation and demonstrated cytotoxic properties in vitro. Annexin V/PI and mitochondrial membrane potential assays indicated that dose-dependent induction of apoptosis was the main mechanism. Combination (viscumTT) of lectin- (viscum) and triterpene-containing (TT) extracts resulted in greatest induction of apoptosis. Furthermore, caspase activity demonstrated that these extracts were able to induce apoptosis through both caspase-8 and -9 dependent pathways. In vivo experimentation showed that treatment of mice with viscumTT combination prolonged mean survival to 50.5 days compared to 39.3 days in the phosphate-buffered saline group.


CONCLUSIONS
Here for the first time, we have demonstrated that either solubilized triterpene acids or lectins and combinations thereof, induce dose-dependent apoptosis in the ALL cell line NALM-6 via caspase-8 and -9 dependent pathways.
Department of Paediatrics, Division of Oncology/Haematology, Otto Heubner Centre for Paediatric and Adolescent Medicine (OHC), Charité, Universitaetsmedizin Berlin, Germany.
C I
CI
Delebinski
S
S
Jaeger
K
K
Kemnitz-Hassanin
G
G
Henze
H N
HN
Lode
G J
GJ
Seifert
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage* / Q000302:isolation & purification; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D004357:Drug Synergism; D005260:Female; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D016513:Mice, SCID; D009828:Oleanolic Acid / Q000008:administration & dosage; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification; D037121:Plant Lectins / Q000008:administration & dosage / Q000302:isolation & purification; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D012995:Solubility; D014315:Triterpenes / Q000008:administration & dosage* / Q000302:isolation & purification; D028182:Viscum album / Q000737:chemistry*; D023041:Xenograft Model Antitumor Assays
D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts; D037121:Plant Lectins; D014315:Triterpenes; D009828:Oleanolic Acid; D045304:Cytochromes c; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9