Professor of chemistry and biochemistry at the University of Texas at Arlington, Fred MacDonnell, and his colleagues have discovered ruthenium-based complexes that may be useful in controlling cancer that are less toxic than current chemotherapies. This work was done in conjunction with the City of Hope Comprehensive Center in Duarte, California. The idea is to find complementary therapies using this platinum-based system such as cisplatin that do not have severe side effects.
These newly developed ruthenium polypyridyl complexes (RPCs) are believed to be effective against human non-small lung cancer cells as based on pre-clinical tests.
According to pre-clinical lab tests, RPCs are able to clear from the body without being metabolized without any kidney complications. It is reported that normal cells can handle more than 10 times the amount of ruthenium complexes as cancer cells so no damage should occur to normal tissue. It is also known that RPCs have the ability to target hypoxic cells, which means they attack cancer cells only.
According to Macdonnell, current cancer drugs tend to be insensitive to the oxygen state of cells. Given that cancer cells are in a state of hypoxia (low oxygen), a therapy that recognizes this and attacks specific cells that are hypoxic would be beneficial.
The mechanism at play here has to do with the RPCs structure. This structure involves a tatpp structure which is redox-active. This complex actually binds to DNA and becomes reduced in the process. It is believed that this reduction process initiates the cell to go through programmed cell death (apoptosis) specifically in cancer cells. This process is more likely to occur in cells that are hypoxic, since the complex reduces more readily in this case. Moreover, they believe that RPCs enter cancer cells more often than normal cells because they are more metabolically active, however, more research is necessary to validate this assumption.