Researchers have found that combining chemo and light therapy into one treatment called Ru-Pt makes a more powerful impact on cancer cells than either therapy alone.
Combining therapies can be beneficial because it makes it possible to reach some cancers that are drug-resistant, and can also reduce side effects. Researchers found that to be true for Ru-Pt.
The chemo component is cisplatin (brand name Platinol), which contains platinum. It’s one of the most common chemo drugs. It binds to the DNA in tumor cells and damages it so badly that the cell can’t repair itself, which triggers cell death. A chemical enhancer called phenylbutyrate is often combined with cisplatin to increase its efficacy. It was also used in this study.
In photodynamic therapy (PDT), a metal complex is delivered directly to the cell. It’s then activated by laser light, which triggers the formation of oxygen. This damages the cell’s metabolism and triggers cell death. The PDT used in this particular study was a ruthenium metal complex.
The drugs were combined so that they would reach the cells simultaneously and therefor increase their impact — something other clinical trials don’t typically do.
“In clinical protocols, each drug is administered separately and may not reach the tumor at the same time or at a fixed ratio,” said lead author Gilles Gasser, a professor from the Paris Sciences et Lettres (PSL) University in Paris, France.
The study was published in Angewandte Chemie, one of the best chemistry journals in the world, that’s produced by the German Chemical Society.
Researchers at the Paris Sciences et Lettres (PSL) University led by Gilles Gasser and researchers from Hebrew University in Jerusalem led by Professor Dan Gibson collaborated on the study.
They combined cisplatin, phenylbutyrate, and the PDT drug into one compound that they dubbed Ru-Pt. Then they tested to see how it would interact with cells in a lab setting. (The goal for treatment would be to inject it into a patient’s bloodstream where it will reach the targeted tumor cells and wreak havoc in one neat package).
Cisplatin (paired with phenylbutyrate) and the PDT drug are connected by a molecular spacer so that they can reach the cells at the same time without affecting the other drug’s work. This also help reduce side effects.
“The correct spacer length was critical to ensure that both drug compounds will not interfere with each other, but the molecule remains small, water-soluble, and able to travel across membranes,” Gasser said.
The researchers tested the treatment in the lab, on healthy cells and cancer cells. Once the drugs reached the tumor, the chemo portion got to work immediately while they shined a laser light on the same spot to activate the PDT.
They found that Ru-Pt had a deadly impact on cancer cells. It had an especially lethal impact on cancer cell lines that were resistant to other drugs — Ru-Pt destroyed up to 10 times more cancer cells than the treatments could on their own.
The results are promising and show the high potential of combining drug treatments into one effective package.
More research needs to be done, as this was done on cells in a lab environment. We look forward to hearing more developments in this research.