According to researchers from the School of Medicine at Washington University in St. Louis, in contrast to conventional phototherapy, a new way to fight cancer targets tumor cells that have spread deep inside the body.
New research, light used as part of conventional methods of cancer treatment to detect metastatic tumors affects the light-sensitive drugs. A study shows that when such drugs attacking cancer cells, the light-sensitive drug produces toxic free radicals that kill tumor cells. Scientists have shown that this technique works effectively in mice with multiple myeloma, cancer of leukocytes and aggressive metastatic breast cancer.
The work is published online in Nature Communications.
"The spread of cancer throughout the body remains the leading cause of death in patients, - says senior author Samuel Achilefu, professor. - Research shows that Phototherapeutic technology is particularly suited for treating small tumors that spread to different parts of the body, including the bone marrow. "
The technology uses a chemotherapeutic drug, called titanocenes. The titanocene was not effective as a chemotherapeutic agent in clinical trials, even at relatively high doses. But when exposed to light radiation titanocene generates reactive particles that are toxic to even low doses of cells.
The researchers placed the lowest dose titanocene into nanoparticles, which were aimed at proteins located on the surface of cancer cells. They found that when the nanoparticles are in contact with cancer cells, their membranes fuse together to release the titanocene into the cells. The new method is less toxic than standard chemotherapy. Studies show that the body gets rid of titanocene through the liver.
In mice with multiple myeloma technology used once a week for four weeks. In the following weeks, the mice had smaller tumor volume compared to control mice. Survival was not less than 90 days as compared to 50% of the mice that survived 62 days. According to the researchers, mice with breast cancer also showed antitumor effect of the treatment, although it was less pronounced than in animals with multiple myeloma, which is probably due to the extreme aggressiveness of breast cancer cells. The researchers found that some types of multiple myeloma resistant to the new method.
"When we got to the cells that were resistant to phototherapy, and saw that the surface of the protein, which we aim, was not. We want to see if we can identify other surface protein for the attack and the destruction of resistant cells together with myeloma cells that respond to initial therapy, which can lead to a complete remission, "- says Achilefu.