Presentation on Coordination Compounds

Instead of having our normal seminar class this Monday, one of the professors from the University of Siena gave a presentation on her research. Gabriella Tamasi presented on “Release Studies from Smart Hydrogens as Carriers for Coordination Compounds that Contain Active Drugs as Ligands.” The goal of her research is to develop new ways to deliver drugs, particularly cancer fighting drugs. The presentation was a bit difficult to follow. Trying to understand complex chemistry in an Italian accent is a challenge. I did, however, learn a lot about a type of compound I had not encountered before, and how this type of compound can fight cancer.
The compounds under investigation were coordination compounds. Coordination compounds are made of two parts. The outer part is made of molecules called ligands that contain elements with lone pair electrons, most commonly nitrogen and oxygen. These ligands attach themselves to metal atom or ion to form the compound. Transition metals are common in these compounds because they can form multiple bonds with their d or f orbitals. In Gabriella’s lab, they are developing new treatments by using active drugs as ligands. The metals being tested are copper (Cu), platinum (Pt), and Rutherium (Ru) because these metals by themselves have some therapeutic properties such as being an anti-inflammatory agent. The ligands come from a family of drugs called oxicams. Oxicams are non-steroidal anti inflammatory drugs that also have radical scavenging properties. Gabriella showed graphs comparing the radical scavenging activity of coordination compounds containing oxicams to that of the free ligands. Attaching these molecules to metals make them better antioxidants, and more active in other important ways as well. Creating coordination compound is also useful in the delivery of the drug. The metal complex prevents enzymatic degradation of the drug and allows for multiple therapies to be delivered at the same time.
To understand how these drugs could be used to fight cancer, I had to learn a little about how cancer cells are different from normal cells. In normal cells the DNA in contained within the membrane of the nucleus. During cell division the nuclear membrane dissolves and the DNA is briefly exposed to the general volume of the cell before new membranes form in the divided cells. Cancer cells are generally dividing very frequently, so the DNA is more exposed than in healthy cells. The metal complex, which is close to planar in shape, inserts itself between the two strands of the DNA distorting the helix and disrupting replication which kills the cell.