Are isothiocyanates from cruciferous vegetables potential therapeutic agents for breast cancer

Abstract

Background: The important role of food bioactive compounds in the reduction of cancer risk has been highlighted by extensive research over the last two decades. Consumption of cruciferous vegetables in particular, rather than vegetables as a group has drawn a great deal of attention in cancer research due to their potential protective properties. The health benefits of cruciferous vegetables have been well reported being attributed to their rich sources of isothiocyanates and indole constituents. This paper focused on the activity of isothiocyanate constituents in breast cancer. Methods: Studies and data sources: Medline and Pubmed were searched for studies using key terms isothiocyanate and breast cancer as text words and as exploded subject headings where possible. Other key terms such as sulforaphane, benzyl isothiocyanate, phenethyl isothiocyanate, allyl isothiocyanate and breast cancer were also searched to check for appropriate studies. The search included all studies published from 1995 up to December 2015. Relevant studies cited in the primary-search published before 1995 were also included in the review. Inclusion criteria: The following inclusion criteria were applied in the screening of articles: 1) study published in English; 2) study compared ITC treated group with a control; 3) study examined breast cancer tumour or breast cancer cells; 4) study examined anticancer effect; 5) statistical analysis was provided. The search resulted in 3 human clinical trials and 49 preclinical in vivo and in vitro studies. Results&Discussion:There were substantial preclinical data over the last two decades, which reported the activity of various isothiocyanate constituents in breast cancer cell lines and animal models of breast cancer tumour, with a limited number of studies from human clinical trials. Recent studies have also found that isothiocyanates exhibited significant activity against breast cancer stem cells as well as breast cancer bull cells, which is generally thought as a new and innovative approach for targeting breast cancer treatment. The most extensively investigated cruciferous vegetables’ active constituents included sulforaphane, benzyl isothiocyanate and phenethyl isothiocyanate, and overall, at pharmacological concentration range of 1-10 µM for sulforaphane and 2.5-5 µM for benzyl isothiocyanate, and phenethyl isothiocyanate with a wide undefined, varied range of concentrations, these food bioactive compounds demonstrated a highly desirable activity at the cellular and molecular levels, therefore they are likely to show great promise for use in humans as anti-cancer therapeutic agents.