Induction of GST and NQO1 in cultured bladder cells and in the urinary bladders of rats by an extract of broccoli (Brassica oleracea italica) sprouts.

Deficiency of glutathione S-transferase (GST) or NAD(P)H:quinone oxidoreductase 1 (NQO1) in humans is associated with increased risk of urothelial bladder cancer. Broccoli sprouts are a rich source of several isothiocyanates (ITCs), particularly sulforaphane (SF) which has shown promising chemopreventive activities. We report herein that a broccoli sprout ITC extract significantly induced both GST and NQO1 in cultured bladder cells in vitro and in rat bladder tissues in vivo.

Evaluation of isothiocyanates as potent inducers of carcinogen-detoxifying enzymes in the urinary bladder: critical nature of in vivo bioassay.

Deficiency of carcinogen-detoxifying phase 2 enzymes, such as glutathione S-transferase (GST) and NAD(P)H:quinone oxidoreductase 1 (NQO1), increases bladder cancer risk in humans. We report that several isothiocyanates (ITCs) that have not been previously examined, 1-methylbutyl ITC in particular, potently and preferentially induce both GST and NQO1 in the rat bladder. Comparison of 25 ITCs that are closely related in chemical structures showed that a 3-5-carbon aliphatic side chain with a methyl group attached to the alpha carbon was crucial for maximal inducer activity in the bladder.

Potent activation of mitochondria-mediated apoptosis and arrest in S and M phases of cancer cells by a broccoli sprout extract.

We have previously shown that broccoli sprouts are a rich source of chemopreventive isothiocyanates, which potently induce carcinogen-detoxifying enzymes and inhibit the development of mammary and skin tumors in rodents. However, the principal isothiocyanate present in broccoli sprout extracts, sulforaphane, not only induces carcinogen-detoxifying enzymes but also activates apoptosis and blocks cell cycle progression. In this article, we show that an aqueous extract of broccoli sprouts potently inhibits the growth of human bladder carcinoma cells in culture and that this inhibition is almost exclusively due to the isothiocyanates.