Cruciferous vegetables and lung cancer

Andrea Sapone a,*, Alessandra Affatato a, Donatella Canistro a, Laura Pozzetti a, Massimiliano Broccoli a, Jessica Barillari b, Renato Iori b, Moreno Paolini a a Department of Pharmacology, Molecular Toxicology Unit, Alma Mater Studiorum, University of Bologna, via Irnerio 48, Bologna, Italy b Agricultural Research Council – Research Institute for Industrial Crops (CRA-ISCI), via Corticella 133, Bologna, Italy

A number of epidemiological studies have shown an inverse relationship between cruciferous vegetable consumption (assessed by food frequency questionnaires), and cancer, especially those of lung and stomach [1]. Crucifers, such as broccoli, cauliflower, Brussel sprouts, cabbage and watercress, contain a family of secondary plant metabolites known as glucosinolates, which are fairly unique to these vegetables. Upon hydrolysis, glucosinolates yield a number of breakdown products, mostly isothiocyanates, with supposed chemopreventive properties, as shown in experimental animals [1]. Susceptibility to lung cancer seems to be affected by polymorphisms for glutathione S-transferases (GSTs), a class of enzymes involved in the metabolism of carcinogens, such as those present in tobacco smoke (e.g. polycyclic aromatic hydrocarbons). ...

...It seems therefore that new protective mechanisms of cruciferae in general and isothiocyanates in particular should be considered. The recently discovered ability of such phytochemicals to stimulate Nrf-2 gene-dependent anti-oxidant enzymes, seems to offer a promising starting point [11]. It has been proposed that isothiocyanates could inhibit cancer development through multiple mechanisms, such as reduction of oxidative stress by elevating and maintaining cellular anti- xidants or inhibition of cell proliferation (thereby retarding or eliminating clonal expansion of initiated, transformed, and/or neoplastic cells), although the apparently conflicting pro- and anti-oxidative effects of isothiocyanates remain to be elucidated [12]. Other effects, including anti-inflammatory, anti-bacterial, and induction of differentiation might contribute to the overall protective effects of these compounds.