Prevention of Bladder Cancer with Broccoli Sprouts

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DESCRIPTION (provided by applicant): This project focuses on the cancer preventive activity of broccoli sprout extracts in the bladder. The hypothesis to be tested is that broccoli sprout extracts are able to suppress tumorigenesis in the bladder by inducing carcinogen-detoxifying enzymes, inducing apoptosis, and inhibiting cell proliferation, all of which contribute, perhaps synergistically, to the prevention of carcinogenesis. Molecular markers relevant to these biological events, as well as inhibition of tumorigenesis will be studied. Broccoli sprouts are the richest plant source of sulforaphane, which is known to possess the above-described chemopreventive mechanisms. Both sulforaphane and broccoli sprout extracts have been shown to inhibit tumorigenesis in animal models (non-bladder tissues). Particularly, ingested sulforaphane in humans is disposed rapidly and concentrated in urine, making bladder epithelial cells probably the most exposed cells to sulforaphane in the body. The overwhelming majority of bladder cancers originate from the epithelial cells. Aim 1 is to determine the effect of broccoli sprout extracts on the expression of critical Phase 2 detoxification enzymes in cultured human bladder epithelial cells. Glutathione transferase and UDP-glucuronosyl-transferase, whose deficiencies have been linked to bladder carcinogenesis, will be examined using both enzyme activity analysis and Western blot analysis. Aim 2 is to determine the effect of broccoli sprout extracts on apoptosis and cell cycle regulation in cultured human bladder epithelial cells. The biomarkers include nuclear DNA fragmentation, activation of selected caspases, cell cycle change and related cell cycle regulators, using both flow cytometry and Western blot analysis. Aim 3 is to determine the in vivo cancer chemopreventive activity of broccoli sprout extracts in the rat bladder. Aim 3a is designed to determine the effect of orally administered broccoli sprout extracts on Phase 2 enzymes, apoptosis, and cell proliferation in bladder epithelia. Biomarkers, including the two Phase 2 enzymes listed above, plus the TUNEL and PCNA assays, will be evaluated immunohistochemically. Aim 3b is to determine the effect of orally administered broccoli sprout extracts on N-butyl-N-(4-hydroxybutyl) nitrosamine-induced bladder tumorigenesis. Tumor incidence, tumor multiplicity, and the nature of each tumor will be determined.