Studies on exogenous elicitors promotion of sulforaphane content in broccoli sprouts and its effect on the MDA-MB-231 breast cancer cell line

Abstract

Broccoli (Brassica oleracea var. italica) belongs to the Brassicaceae family and is one of the most important cruciferous vegetables. It has gained popularity due to its high glucosinolate concentrations that have positive potential in cancer treatment. In this study, the effects of two elicitors; methyl jasmonate (MeJA) and salicylic acid (SA), on the production of sulforaphane from broccoli 7-days old seedlings, its antiapoptotic activity and its gene expression have been studied. Real-time PCR was used to quantify myrosinase (MY) gene expression associated with sulforaphane production. The antiapoptotic activity of sulforaphane treatments was evaluated and tested using MDA-MB-231 breast cancer cell line. The highest amount of sulforaphane was produced at 80 μM SA and 40 μM MeJA after 24 h of elicitation. Increased production of sulforaphane was found to be associated with over-expression of myrosinase gene. The sulforaphane extract obtained from broccoli seedlings treated with MeJA exerted a higher inhibitory effect on the MDA-MB-231 breast cancer cell line than sulforaphane extract obtained from broccoli seedlings treated with SA. The inhibitory effect increased by using purified sulforaphane. Studies on apoptosis gene transcription showed that all sulforaphane treatments down-regulated the B-cell lymphoma 2 (Bcl-2) gene (antiapoptotic) transcription while up-regulating the pro-apoptotic Bcl2 Associated X, Apoptosis Regulator (Bax) gene, Caspase-3, Caspase-8 and Caspase-9. It may be concluded that increased sulforaphane production could increase its antiapoptotic activity as indicated by induction of more apoptosis in MDA-MB-231 breast cancer cells.