Gene therapy relies on introducing into the body genetic material that can help fight a disease or correct a defect in a patient’s DNA. Finding a safe way to get therapeutic genes into the cells has been a major challenge, however. Many trials have used viruses as carriers, but this approach has run into problems with toxicity and dangerous immune system responses. So a new wave of gene therapy research is turning to nanoparticles to get the job done.
Cancer researcher Janet Sawicki of the Lankenau Institute for Medical Research in Pennsylvania, chemical engineer Robert Langer of MIT, and their colleagues are investigating biodegradable nanoparticles to deliver gene therapy for ovarian cancer. Their treatment uses the gene for diphtheria toxin, which causes cell death. Specific DNA sequences attached to the gene help to ensure that it targets only cancerous cells, killing them while leaving healthy ones alone. “That’s in contrast to chemotherapy,” Sawicki says, “which often damages healthy cells and causes bad side effects.” She had originally planned to use viruses to carry the gene but worried about the risks. The nanoparticles, developed by Langer, seemed a safer option. The team’s recent study in mice has found that the treatment reduced the mass of ovarian cancer tumors and was more effective at suppressing tumor growth than chemotherapy. The researchers hope to begin clinical trials in humans next year.
Other researchers are investigating related nanoparticle delivery systems, also with promising results. In France, Georges Vassaux of the Institut National de la Santé et de la Recherche Médicale and colleagues reported last year that they had identified a nanoparticle that delivers its cargo exclusively to cancerous cells in mice. Vassaux’s team next plans to test gene therapy carried by nanoparticles on a variety of tumors in animals.