Finding new uses for an old drug is a noteworthy endeavor. If the drug is already approved for use in another capacity, researchers can significantly shorten the time it takes before the drug can be prescribed to patients for new applicable uses. Thus the team at St. George’s, University of London, are quite hopeful the discovery will expedite future clinical trials for cancer treatment.
In studying the effects of naltrexone on cancer cells, the team observed that the cells stopped growing. They also reported naltrexone altered the cells’ internal working mechanisms, causing certain genes to be turned on at higher intensity. This ultimately led to the cells killing themselves more readily, thus reducing the cancer growth.
"Rather than stopping the cancer cells from growing, patients want to be rid of them. We saw that by giving the drug for two days, then withdrawing it, cancer cells would stop cycling and undergo cell death," said Wai Liu, first study author.
Through further investigation, the team found that naltrexone selectively affected genes involved in regulating the cell cycle and the immune system. Genes that are involved with programmed cell death were also triggered by naltrexone, implicating a mechanism for the increased deaths of the cancer cells.
"We have shown that the genetic fingerprint of naltrexone differs according to the different doses used, which identifies new ways of using it as an anti-cancer treatment,” said Liu. The doses used in the study are much lower than what’s used in treating addiction.
Naltrexone is commonly used to treat alcoholism. And as an opioid antagonist, this drug is also used to treat opioid addiction. At high doses, there’s a risk for liver damage and gastrointestinal problems.
And because the drug is already approved and on the market, it becomes that much more attractive. Liu, who has been researching cancer treatments for over two decades, hopes clinical trials will lead to naltrexone use in conjunction with other anticancer treatments. "We have taken a drug that is relatively safe in humans, and reformulated a new use for it; this has only been possible by understanding the dynamics of a drug. How many other drugs can be improved in this way?” asked Liu.
Additional source: MNT