Stem Cell Systems Target Metastatic Melanoma in Mouse Model

A team of Harvard Medical School-led researchers has developed a pair of stem cell systems that target metastatic melanoma in mice. Melanoma that has spread to the brain has an overall survival of four to six months, and recent studies of immunotherapies have not shifted that prognosis, they note. In Science Translational Medicine this week, the researchers describe a system they say may better target the disease. One of the stem cell systems they designed harbors an oncolytic herpes simplex virus, while the other has undergone CRISPR-Cas9 editing to knock out nectin 1 to make it resistant to the virus contained by the first stem cell system and to also release immunomodulators like GM-CSF. Using stem cells to deliver the virus, the researchers adds, shields it from degradation by circulating antibodies. Then in a mouse model of melanoma with leptomeningeal metastases, the researchers found that their therapy could boost immune responses. "We have now developed a new immuno-therapeutic approach that is sustainable and delivered locally to the tumor. We believe that locally delivered immunotherapies represent the future of how we will be treating metastases to the brain," author Khalid Shah from Brigham and Women's Hospital and Harvard say in a statement.