Adding a mushroom extract to interferon therapy for prostate cancer significantly improves the treatment’s effectiveness, and may help reduce both its cost and side effects, according to a study published in the Journal of Hematology and Oncology.
Prostate cancer is the second deadliest cancer among elderly men in the United States. Although treatments such as surgery, chemotherapy, radiation, and hormone therapy are available, their benefits aren’t always long-lasting, they can have significant side effects, and the disease can return. Another treatment option is immunotherapy with a class of drugs known as interferons. These drugs provoke the body’s immune system to respond against the cancer, and they are thought to inhibit the cancer cells’ ability to grow and differentiate. However, studies on interferons have shown mixed results.
“The efficacy of these interferons has not been as good as we expected and also they are rather expensive,” says study author Sensuke Konno, PhD, associate professor in the Department of Urology at New York Medical College.
To improve the effectiveness of interferons and reduce the cost of treatment, researchers have been looking at combining these drugs with other substances. Dr. Konno investigated a treatment combining interferon-alpha with D-fraction (PDF), an extract from the maitake mushroom (Grifola frondosa). Past studies have shown that this extract can stimulate an immune response against cancer cells. Dr. Konno and his team wanted to find out if the two substances combined might have a synergistic effect on prostate cancer cells.
The authors tested out the two substances, first alone and then together, on prostate cancer cells in the laboratory. Individually the interferon and mushroom extract had no real effects on the cancer, except in very high doses. However, when the two substances were combined, they slowed the growth of prostate cancer cells by up to 65 percent. The combination of the two substances effectively halted the cancer cell cycle, preventing the prostate cancer cells from dividing and multiplying.
Combining interferon-alpha and PDF also reduced the amount of each drug that was needed. Interferon was reduced to one-fifth of its original dose. “It is thus plausible that PDF may not only help potentiate the interferon activity, but also help cut the cost down,” says Dr. Konno.
Dr. Konno is cautiously optimistic about the possibility of using combinations of interferon and PDF or other substances in the future. “Although the combination of interferon and PDF in our study looks good and promising, I try to be a little more cautious because this is an in vitro study (using cell cultures) and we still have a long way to go,” he explains. The next step in the research would be to test out this treatment combination on animals with cancer to determine the appropriate dose, and learn whether it might cause any unwanted side effects. Depending on the results of animal studies, the combination therapy might move forward into human clinical trials.
Pyo P, Louie B, Rajamahanty S, Choudhury M, Konno S. Possible immunotherapeutic potentiation with D-Fraction in prostate cancer cells. J Hematol Oncol. 2008;1:25.