This past Sunday sons and daughters far and wide thanked their mothers for all the love and wisdom they provided. I hope they also thanked mom for nagging them to eat their veggies especially the cruciferous ones like broccoli, Brussels sprouts and cabbage. Based on research from South Dakota State University (SDSU), it turns out these foods contain a natural plant chemical that appears to kill cancer stem cells, the cells thought to be responsible for the reoccurrence and spread of certain cancer types.
Like stem cells, cancer stem cells can make copies of themselves. But instead of growing into tissues and organs, cancer stem cells propagate the cancer and mature into the many cell types found in a tumor or leukemia. Standard treatments like chemotherapy and radiation target rapidly dividing cancer cells but the cancer stem cell can lie dormant and evade these treatments. Plus they only make up a small percentage of the cancer. So a seemingly successfully treated patient can relapse if any cancer stem cells remain and begin propagating the tumor once again. The SDSU team and others had previously shown that the plant chemical phenethyl isothiocyanate (PEITC) – formed by an enzymatic reaction during the chewing process – had anti-inflammatory and cancer cell killing properties. In research published last summer and reported just last week in a university press release, the researchers for the first time looked at the effects of PEITC on cancer stem cells. They isolated cancer stem cell-like cells from HeLa cells, a cervical cancer cell line (the cells made famous by The Immortal Life of Henrietta Lacks). In petri dish experiments they showed that PEITC had a potent effect on the cancer stem cells, killing 75% within 24 hours. Detailed analysis suggested that PEITC acted by increasing the level of proteins involved in programmed cell death, also called apoptosis.
To provide a proof of principle that this cancer cell killing activity of PEITC has the same effects in the body, the team studied tumor formation in mice after injection of the cancer stem cells with or without pretreatment with PEITC. Sure enough, the PEITC treated animals showed a 70% reduction in tumor formation compared to the untreated group. To study potential effects of PEITC on the spread of tumors to other parts of the body, the team analyzed lung tissue in the animals. Only untreated animals had tumors in the lung tissue suggesting that PEITC blocked tumor spreading. Certainly more testing is needed to confirm these results in humans but if every thing pans out, PEITC clinical trials could be on the horizon, either alone or in combination with cancer therapies that target programmed cell death. In the meantime, it can’t hurt to listen to mom and take a second helping of broccoli. CIRM funds a number of projects, including three clinical trials, that focus on cancer stem cells. For more information, please visit these web pages: