Anticancer Effects of Viscum album Fraxini Extract on Medulloblastoma Cells in vitro.

BACKGROUND: Mistletoe therapy is frequently administered as a supportive treatment in diverse pediatric cancer entities including brain tumors. Medulloblastoma is the most common brain tumor in childhood. Its high risk to metastasize and its long-term sequelae caused by aggressive chemo- or radiotherapies are still challenging. MATERIAL AND METHODS: Effects of a lectin-rich mistletoe extract, abnobaVISCUM Fraxini, were investigated in two medulloblastoma cell lines (Daoy and ONS-76). Responsiveness of tumor cells was assessed by cell viability assays and xCELLigence real-time analyses. Moreover, impacts on proliferation, cell cycle and apoptosis were investigated. Apoptosis was studied by staining of vital mitochondria and assessing the involvement of caspases. In addition, effects on migration and invasion were analyzed. RESULTS: Both medulloblastoma cell lines were more susceptible to treatment with the mistletoe extract than a nontumorigenic fibroblast cell line. In mistletoe-sensitive Daoy cells, reduction of proliferation and induction of caspase-mediated apoptosis were observed upon administration of 0.05 and 0.5 mg/mL abnobaVISCUM Fraxini treatment, respectively. Furthermore, mistletoe extract inhibited migration and invasion properties in Daoy and significantly impaired invasive capabilities of ONS-76 cells. CONCLUSION: AbnobaVISCUM Fraxini has cell line dependent antitumoral effects in medulloblastoma models. These results call for further investigations, to reveal mechanistic insights into antitumorigenic properties of mistletoe extracts.

Antitumoral Effects of Curcumin (Curcuma longa L.) and Thymoquinone (Nigella sativa L.) on Neuroblastoma Cell Lines.

INTRODUCTION: Overall survival of high-risk neuroblastoma patients is still poor, emphasizing the need for novel therapeutic options. There is evidence for anti-cancer properties of the herbal substances thymoquinone and curcumin. These substances are isolated from Nigella sativa L. and Curcuma longa L., respectively, which are used in traditional medicine. OBJECTIVE: We investigated cytotoxic effects of thymoquinone and curcumin on neuroblastoma cell lines NLF, NB69, and SK-N-BE(2), in vitro. METHODS: Cytotoxicity of compounds was investigated by MTT cell viability assays. For analyzing effects on cell proliferation BrdU assays were employed and induction of apoptosis was detected by Cell Death ELISA assays. RESULTS: Both substances showed cytotoxic effects in all three neuroblastoma cell lines, whereby primary human fibroblast cells reacted less sensitively. Overall, lower IC50 values could be calculated for curcumin (3.75-7.42 µM) than for thymoquinone (5.16-16.3 µM). Decreased proliferation and increased apoptosis rates were observed under treatment. CONCLUSIONS: Both substances showed anti-tumoral properties on neuroblastoma cell lines and should be further investigated as therapeutic agents.

Preclinical Evaluation of Antitumoral and Cytotoxic Properties of Viscum album Fraxini Extract on Pediatric Tumor Cells.

In Europe, especially in German-speaking countries, administration of mistletoe extracts is the most common and popular complementary and alternative therapy approach reported in oncology. Mistletoe therapy is applied to children with cancer for curative and palliative therapeutic regimes with increasing frequency, but at the same time, there are only a few studies on the effectiveness of this therapy. Therefore, we have investigated the response of various pediatric cell lines (acute myeloid leukemia, Ewing's sarcoma, hepatocellular carcinoma, medulloblastoma, neuroblastoma, and osteosarcoma) to mistletoe extract, abnobaVISCUM Fraxini. Effects on cell proliferation, cell cycle distribution as well as on mitochondrial integrity and caspase-mediated apoptosis were investigated in neuroblastoma cell lines, SH-SY5Y and Kelly. Additionally, in vitro tumor cell migration and invasion were studied. In vivo effects of the mistletoe extract were investigated in a syngeneic neuroblastoma mouse model. We could show that tumor cell lines were from 5- to 640-fold more sensitive to abnobaVISCUM Fraxini treatment than non-tumorigenic fibroblasts, whereby neuroblastoma cell lines were the most sensitive. For two neuroblastoma cell lines, SH-SY5Y and Kelly, induction of caspase-9-mediated apoptosis, a decrease of mitochondrial integrity as well as attenuation of migration and invasion were observed. In vivo experiments revealed a reduction of tumor growth and a prolonged survival of tumor-bearing animals. In summary, we can state that these results provide the first preclinical data for cytotoxic activities of abnobaVISCUM Fraxini for a broad panel of pediatric tumor cell lines, in particular, neuroblastoma cells. Thus, it might be a potential remedy for the supportive treatment of neuroblastoma.