The tissue of cruciferous vegetables, like broccoli, cauliflower, cabbage and Brussels sprouts, contain high levels of the active plant chemicals glucosinolates. These are metabolised by the body into isothiocyanates, which are known to be powerful anti-carcinogens.
Ravi Sahu and Sanjay Srivastava from Texas Tech University Health Sciences Center in Amarillo report that the one such isothiocyanates - benzyl isothiocyanate (BITC) - may be protecting against tumours in the pancreas via a mechanism dependent on the protein STAT-3.
The results, published online ahead of print in the Journal of the National Cancer Institute, study extends out understanding of the potential anti-cancer benefits of such vegetables, and may offer important information to companies involved in the production of extracts for the functional food and dietary supplements industry.
Supplements containing broccoli extracts are available on the market, such as Cyvex Nutrition's BroccoPlus and BroccoPhane, delivering high doses of glucosinolates in powder form.
Sahu and Srivastava investigated the effects of BITC on pancreatic cancer cell lines grown in culture and on a mouse model of pancreatic cancer. Using different BITC concentrations ranging from five to 40 micromoles, the researchers incubated the human cells with the compound and studied how STAT-3 protein activation was affected.
According to background information from the authors, the STAT-3 protein promotes the survival and proliferation of cancer cells.
Exposure of the cells to BITC reportedly increased cell death (apoptosis) by reducing the amount of activated STAT-3 protein. When cells were used that over-expressed STAT-3 the protective effect of BITC was eliminated, they said.
Importantly, the researchers added that the health of normal pancreatic cells was not affected by BITC.
"Taken together, these findings may provide the basis for further preclinical and clinical investigation of BITC for the chemoprevention and/or chemotherapy of pancreatic cancer," concluded the authors.
Sahu and Srivastava noted the limitations of their study, including that only a small number of animals were used. Moreover, these in vitro and in vivo studies can not be directly translated to humans, and significant further studies are needed to deepen the understanding of how STAT-3 affects pancreatic cancer development, and the potentially protective benefits of cruciferous vegetables and their compounds.
Pancreatic cancer is the eighth most common cancer in women, and the 11th most common cancer in men in the UK. Each year, there are almost 3,600 new cases in women, and over 3,300 cases in men.
Source: Journal of the National Cancer InstitutePublished online ahead of print, doi:10.1093/jnci/djn470 "The Role of STAT-3 in the Induction of Apoptosis in Pancreatic Cancer Cells by Benzyl Isothiocyanate"Authors: R.P. Sahu, S.K. Srivastava