Researchers have recently discovered a way to kill prostate cancer cells with copper. A team of scientists and researchers at Duke Medicine combined copper and another drug and were able to destroy diseased cells, leaving non-cancer cells healthy.
Fighting Prostate Cancer with Copper
Prostate cancer tumors steal and hoard copper; an essential element in the human body. However, researchers have recently discovered a way to kill prostate cancer cells by combining copper and another commercially available drug called disulfiram.
Disulfiram is a drug already approved by the U.S. Food and Drug Administration (FDA) to treat alcoholism. In the past disulfiram was also used in treating prostate cancer by homing in on additional copper in the prostate cancer tumors; however, results were disappointing in clinical trials involving patients with advanced stages of prostate cancer.
Donald McDonnell, Ph.D., chairman of the Duke Department of Pharmacology and Cancer Biology and the senior author of a study published in Cancer Research, a journal of the American Association of Cancer Research said, “This proclivity for copper uptake is something we have known could be an Achilles’ heel in prostate cancer tumors as well as other cancers. Our first efforts were to starve the tumors of copper, but that was unsuccessful. We couldn’t deplete copper enough to be effective.”
Dr. McDonnell further elaborated, “So we thought if we can’t get the level low enough in cancer cells to kill them, how about we boost the copper and then use a drug that requires copper to be effective to attack the tumors. It’s the old if-you-can’t-beat-‘em-join-‘em approach.”
Steps Taken to Achieve Success
In an attempt to identify therapies that rely on copper being effective in attacking prostate cancer tumors, Dr. McDonnell, and his colleagues combed through libraries and thousands of therapies. The team from Duke found disulfiram, which they ultimately combined with copper, resulting in dramatically reducing tumor growth in the prostate in test animals with advanced stages of the disease.
To their astonishment, the researchers additionally found that male hormones known as androgens increased the accumulation of copper in cancer cells. This finding is important, in that combining disulfiram and copper, or compounds comparable to disulfiram, may be especially beneficial for males who have been on unsuccessful hormone therapies; therapies that were incapable of reducing the growth of tumors.
Dr. McDonnell explains, “Unfortunately, hormone therapies do not cure prostate cancer, and most patients experience relapse of their disease to a hormone-refractory or castration-resistant state. Although tremendous progress has been made in treating prostate cancer, there is clearly a need for different approaches, and our findings provide an exciting new avenue to explore.”
Associate professor of medicine, Andrew Armstrong, M.D. also participated in Duke’s recent study testing disulfiram in males with advanced prostate cancer.
Dr. Armstrong iterated, “While we did not observe significant clinical activity with disulfiram in men with recurrent prostate cancer in our recent clinical trial, this new data suggests a potential way forward and a reason why this trial did not have more positive results. Further clinical studies are now warranted to understand the optimal setting for combining copper with disulfiram or similar compounds in men with progressive prostate cancer, particularly in settings where the androgen receptor is active.”
The National Institutes of Health, with Dr. McDonnell as the lead author and additional study authors including Michael R. Zalutsky, Katharine J. Franz, Erik R. Nelson, Daniel J. George, Satish K. Chitneni, and Rachid Safi, funded this provocative prostate cancer study.
In the coming months, clinical trials of the combination therapy are planned.
