The patent, granted to researchers at the Texas Agricultural Experiment Station, is based on derivatives of DIM, or diindolylmethane, a natural compound derived from certain vegetables.
It has been picked up by Plantacor, a new biotech company headquartered at the same institution, and is soon to enter clinical trials in collaboration with M.D. Anderson in Houston.
"We took advantage of a natural chemical that research has shown will prevent cancer, and developed several more analogs," said Dr Steve Safe, an Experiment Station chemist studying cancer.
DIM is already commercially available in the US as a natural supplement for cancer prevention and for treating oestrogen-related health issues. In May, researchers at the University of California, Berkeley, reported finding that the chemical, produced when digesting cruciferous vegetables like broccoli and kale, could stifle the growth of human prostate cancer cells. They said it was the first plant-derived chemical found to act as an anti-androgen.
Safe's team first tested chemically altered DIM from broccoli and found it to inhibit the growth of breast cancer cells in laboratory studies. Subsequent research showed these compounds also inhibited growth of pancreatic, colon, bladder and ovarian cancer cells in culture. Limited trials on lab mice and rats have produced similar results, according to Safe.
His team investigated how the compounds block cancer cell growth and found that they target PPAR gamma, a protein that is highly active in fat cells. However, this same PPAR gamma is over-expressed in many tumours and tumour cells and is a potential target for new drugs.
Safe's lab chemically modified 'natural' DIM to give a series of compounds that target the PPAR gamma and stop the growth of cancer.
"One of the best parts is that this treatment appears to have minimal or no side effects, in the mice trials; it just stops tumour growth. The hope now is that the patented chemicals can be developed into useful drugs for clinical trials and then be used for cancer treatment," said Safe.
Future studies in humans are required before it can be judged beneficial in people.
A researcher at the University of Pittsburgh Cancer Institute recently received a $1.7 million grant from the National Cancer Institute to study prostate cancer prevention by phytochemicals found in broccoli.