KOBE - A research team at Konan University in the city of Kobe has developed an effective photodynamic cancer therapy, which specifically targets a protein that facilitates tumor growth and metastasis.
As abnormal functioning of proteins in the so-called RAS family has been known for causing cancer, therapies targeting RAS have been thought to be a potentially effective approach. However, due to the proteins’ structural features, no practical medicine has so far been developed.
According to the university’s announcement and a research article by the team published online by the British scientific journal Nature Communications, professor Daisuke Miyoshi and colleagues have now successfully controlled the generation of NRAS, one of the RAS proteins that helps cancer grow and metastasize, using a photodynamic method.
It is difficult to directly destroy the NRAS protein because its spherical shape makes it hard for a chemical compound to bind with the protein’s surface.
The researchers focused on a portion of the messenger ribonucleic acid, or mRNA, that contains genetic information to make the NRAS protein, because the mRNA allows other substances to bind with it easily. They hypothesized that if the NRAS gene-coding portion was removed, NRAS generation would be curbed.
In the research, a photosensitive zinc compound that had already been confirmed to bind only with nucleic acids of the NRAS portion was inserted into human breast cancer cells and exposed to near-infrared light. As a result, the amount of the protein decreased by some 60 percent and the 24-hour survival rate of the cancer cells dropped to 5 percent.
The method also proved effective even under low oxygen conditions, which are usually seen in deep parts of tumors and make photodynamic therapies — which utilize active oxygen to kill cancer cells — inefficient.
“We plan to confirm the effects (of the new photodynamic therapy) in mice, and hope that will lead to the development of a new medicine,” Miyoshi said.