In a new study in PNAS, MIT researchers describe a new platinum compound they've developed for the treatment of various cancers, reports redOrbit.com's Connie Ho. The compound, the researchers add, is more effective than cisplatin at killing cancer cells and could be used to treat a broader range of cancers. As patients also tend to become resistant to platinum therapy, the researchers hope that this new compound, called phenanthriplatin, could provide new treatment options.
Platinum-based compounds work by entering a cancerous cell while positively charged and replace the cells' chloride ions, Ho says. These positive ions then produce cross-links with the negatively charged DNA, causing cell damage and, eventually, apoptosis. However, some researchers discovered that certain platinum compounds only need to bind to DNA at one site, not two, to have the same effects. In 2008, the MIT researchers investigated pyriplatin, a compound similar to cisplatin, but with one of the chlorine atoms replaced by a six-membered pyridine ring with one nitrogen atom and five carbon atoms, Ho says. For this study, the researchers built on that work, creating compounds with larger rings. "The compound ended up being phenanthriplatin, which was compared against 50 other types of cancer cells under the National Cancer Institute's cancer-drug screening program," Ho says. "Phenanthriplatin was discovered to be four to 40 times stronger than cisplatin, [depending] on the cancer cell. It also proved to have a different pattern of activity than cisplatin, which demonstrated that it could possibly be used to treat cancers that were resistant against cisplatin." The new compound is also able to target cancer cells more efficiently than cisplatin, she adds, and it can inhibit transcription.