Galactoside specific VAA lectin- induced apoptosis in human leukemic cells

Journal/Book: Proceedings of the American Association for Cancer Research 35, 6. 1994;

Abstract: The galactoside-specific lectin VAA purified from mistletoe consistingof 29-kD toxic subunit-alpha and 34-kD carbohydrate-binding beta-subunithas been demonstrated to induce an antitumor/immunostimulatory effect inrabbits, mice, and humans and also induces the secretion of cytokinessuch as TNF-alpha, IL-1, and IL-6 by human mononuclear cells in vitro.Since VAA contains a toxic subunit and causes tumor cell death, in thepresent study we have investigated the ability of VAA to induceapoptosis using a human myelomonocytic leukemic cell line, Croco-ll. Forthese studies we used various concentrations of VAA whole molecule andits separated alpha and beta subunits. A galactoside-specific 14-kDlectin, purified from human placenta was used in all these studies. Ourresults showed that VAA and its carbohydrate specific beta-subunitdecreased the growth of Croco-ll cells in vitro (p less than 0.0001) andinduced apoptosis in a significant number of cells as measured by flowcytometry and DNA degradation analysis techniques. The control 14-kDlectin also decreased the in vitro growth of Croco-II cells but to alesser extent when compared to VAA and did not induce apoptosis in thesecells. Thus, our results demonstrate that the purified lectin frommistletoe may also inhibit cancer cell growth by inducing apoptosis.Author.

Keyword(s): APOPTOSIS/ DE (drug effects)

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