Cytotoxicity mistletoe

Ribosome inactivating cytotoxic protein that irreversibly inhibits protein synthesis in cells, causing cell death. It is a solid obtained from the mistletoe plant (Viscum album). 

Viscum lectin MLI Viscum album (mistletoe) PAG (rRNA) PSI [cytotoxic]... 

Vervecken, W., Kleff, S., Pfuller, U. and Bussing, A. (2000) Induction of apoptosis by mistletoe lectin I and its subunits. No evidence for cytotoxic effects caused by isolated A- and B-chains. Int J Biochem Cell Biol, 32, 317-326. 

The extracts of mistletoe have been shown to inhibit the growth of a variety of animal and human cancer cells in vitro and tumor growth in vivo in a number of animal models. Iscador was found to be selectively cytotoxic to tumor cells while causing no damage to cells of the iimnune system. The antitumor effects of mistletoe reportedly depend on several factors, like the type of host tree, the time of collection during the year, and the manufacturing process. The active principles are found to be lectins, viscotoxins, and alkaloids. 

Btissing, A. 1996. Induction of apoptosis by the mistletoe lectins A review on the mechanisms of cytotoxicity mediated by Viscum album L. Apoptosis l(l) 25-32. 

To circumvent the drawbacks of different preparations from plant material, recombinant mistletoe lectin might be the substance of choice. It can be prepared in large quantities of equal quality.The research of the recombinant form of VAA-1 may also give new clinical perspectives. Recent in vitro investigations with recombinant lectin revealed NK stimulatory effects in synergism with IL-2 and IL-12. Similar to plant lectin in animal models, recombinant VAA-1 was also able to stimulate the NK cell-mediated cytotoxic activity of splenocytes Nat 1mm in press Fig. 4). 

Janssen O, Scheffler A, Kabelitz D (1993) In vitro effects of mistletoe extracts and mistletoe lectins. Cytotoxicity towards tumor cells due to the induction of programmed cell death (apoptosis). Drug Res 43 1221-1227... 

Ribereau-Gayon G, Jung ML, Beck JP (1995) Effect of foetal calf serum on the cytotoxic activity of mistletoe (Yiscum album L.) lectins in cell culture. Phytother Res 9 336-339... 

The most studied activity for mistletoe over the last decade is its antitumor effect. Numerous reports have been published on its efficacy in various human cancer conditions, and against many tumors and cancer cell lines in vivo and in vitro, respectively. " Antitumor mechanisms involve the immunomodulatory effect mentioned above for lectins, as well as apoptosis, antiangiogenesis, cell cycle disruption, and direct cytotoxic effects on cancer cells. ... 

Isolated polypeptides, viscotoxins II, III, and IVb, have been associated with cardio-toxicity but have also been found to exhibit cytotoxic activity against human tumor cells of the KB and HeLa lines in tissue culture. A peptide with a molecular weight of 5000 was found to be cytotoxic to Dalton s lymphoma ascites tumor cells in vitro in mice, without affecting normal lymphocjfies, indicating a cell-dependent specificity also cyctotoxic to Ehrlich ascites cells, both prophylacticaUy and after tumor development. Commercial mistletoe products have been used to treat various cancers in Europe with clinical success. A group of 50 cases of carcinomatous pleural effusions were treated with a topical preparation for an average of 3.3 application over 18 days exudation disappeared in 92% of the patients. In postoperative ovarian cancer patients, a mistletoe preparation statistically increased survival. ... 

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