Mice with neuroblastoma tumors have been successfully treated with genetically modified cells that sought out the cancer cells and activated a chemotherapy drug directly at those sites, according to investigators at St. Jude Children’s Research Hospital and their colleagues at City of Hope National Medical Center (Duarte, Calif.) and the University of British Columbia (Vancouver, Canada). Neuroblastoma is a solid tumor that arises in the part of the nervous system outside the brain.
The researchers also showed that the modified cells migrated to tumors regardless of how small the tumors were or where they were located in the body. A report on this work appears in the Dec. 20 issue of the Web-based journal PLoS ONE.
The study is the first to provide evidence that such cells, called neural stem-progenitor cells (NSPCs), can be used to target solid tumors that have metastasized (spread from their original site), according to the researchers. During normal development NSPCs give rise to all the various types of cells in the brain.
Moreover, since the drug, called CPT-11 (irinotecan), is already used to treat cancers, doctors and scientists already know how the drug behaves in humans. That knowledge should make it easier to translate these laboratory findings to the clinic, the researchers said.
The ability to target tumors with CPT-11 suggests that this technique could let clinicians treat tumors in humans more effectively while avoiding side effects caused by damage to normal cells. The success with neuroblastoma also suggests this technique might improve the treatment of other solid tumors that metastasize, such as colon and prostate cancer.
This homing ability is especially important in the case of high-risk neuroblastoma because even very small tumors that survive after an initially successful treatment often generate more cancer cells that spread and become unresponsive to treatment, said Mary Danks, Ph.D., associate member of Molecular Pharmacology at St. Jude. Therefore, the study holds special promise for children with high-risk neuroblastoma because as many as 80 percent of these patients relapse with chemotherapy-resistant metastatic cancer. Neuroblastoma is considered high risk if the tumors have certain genetic mutations or have already spread when the cancer is diagnosed.