title: Methanolic extract of white asparagus shoots activates TRAIL apoptotic death pathway in human cancer cells and inhibits colon carcinogenesis in a preclinical model.
abstract: Shoots of white asparagus are a popular vegetable dish, known to be rich in many bioactive phytochemicals reported to possess antioxidant, and anti-inflammatory and antitumor activities. We evaluated the anticancer mechanisms of a methanolic extract of Asparagus officinalis L. shoots (Asp) on human colon carcinoma cells (SW480) and their derived metastatic cells (SW620), and Asp chemopreventive properties were also assessed in a model of colon carcinogenesis. SW480 and SW620 cell proliferation was inhibited by 80% after exposure to Asp (80 µg/ml). We demonstrated that Asp induced cell death through the activation of TRAIL DR4/DR5 death receptors leading to the activation of caspase-8 and caspase-3 and to cell apoptosis. By specific blocking agents of DR4/DR5 receptors we were able to prevent Asp-triggered cell death confirming the key role of DR4/DR5 receptors. We found also that Asp (80 µg/ml) was able to potentiate the effects of the cytokine TRAIL on cell death even in the TRAIL-resistant metastatic SW620 cells. Colon carcinogenesis was initiated in Wistar rats by intraperitoneal injections of azoxymethane (AOM), once a week for two weeks. One week after (post-initiation) rats received daily Asp (0.01%, 14 mg/kg body weight) in drinking water. After 7 weeks of Asp-treatment the colon of rats exhibited a 50% reduction of the number of preneoplastic lesions (aberrant crypt foci). In addition Asp induced inhibition of several pro-inflammatory mediators, in association with an increased expression of host-defense mediators. In the colonic mucosa of Asp-treated rats we also confirmed the pro-apoptotic effects observed in vitro including the activation of the TRAIL death‑receptor signaling pathway. Taken together, our data highlight the chemopreventive effects of Asp on colon carcinogenesis and its ability to promote normal cellular homeostasis.
authors.affiliation: University of Strasbourg, Unit EA 4438, Faculty of Medicine, Strasbourg, France.
authors.forename: Souad
authors.initials: S
authors.lastname: Bousserouel
authors.forename: Julie
authors.initials: J
authors.lastname: Le Grandois
authors.forename: Francine
authors.initials: F
authors.lastname: Gossé
authors.forename: Dalal
authors.initials: D
authors.lastname: Werner
authors.forename: Stephan W
authors.initials: SW
authors.lastname: Barth
authors.forename: Eric
authors.initials: E
authors.lastname: Marchioni
authors.forename: Jacques
authors.initials: J
authors.lastname: Marescaux
authors.forename: Francis
authors.initials: F
authors.lastname: Raul
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D027761:Asparagus Plant / Q000737:chemistry*; D001397:Azoxymethane; D063646:Carcinogenesis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003110:Colonic Neoplasms / Q000473:pathology / Q000517:prevention & control*; D004789:Enzyme Activation; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology; D008297:Male; D000432:Methanol / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018520:Plant Shoots / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000187:drug effects / Q000378:metabolism*
chemical_list: D016588:Anticarcinogenic Agents; D010936:Plant Extracts; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D053148:Caspase 3; D053181:Caspase 8; D001397:Azoxymethane; D000432:Methanol