In a significant breakthrough, researchers at the University of Texas at Dallas have developed a potential gene therapy aimed at improving the effectiveness of chemotherapy for neuroblastoma, a pediatric cancer that develops in immature nerve cells. The study, published online on June 4 in Theranostics, demonstrated that the gene therapy approach successfully slowed tumor growth in mouse models of the disease.
Neuroblastoma poses a considerable challenge with a 50% five-year survival rate for patients with high-risk tumors. The researchers found that their gene therapy method worked by expanding the blood vessels surrounding the tumor, thereby enhancing the delivery of chemotherapy drugs. Additionally, the gene therapy made the tumor cells more receptive to chemotherapy, suggesting a potential dual benefit.
Dr. Shashank Sirsi, co-corresponding author and associate professor of bioengineering, expressed enthusiasm about the research, emphasizing the strategy of increasing blood flow to the tumor just before administering chemotherapy. The researchers injected microbubbles, tiny gaseous spheres, into the bloodstream, delivering plasmid DNA programmed to express inducible nitric oxide synthase (iNOS), which expanded blood vessels. When exposed to ultrasound, the microbubbles burst, releasing the iNOS plasmids.
The team administered chemotherapy after the blood vessels expanded and observed increased blood flow to tumors. Moreover, the gene therapy induced iNOS expression in the tumor cells, enhancing the effectiveness of chemotherapy. However, more research is required before the method can be made available for patients.
Dr. Sirsi, who has a personal connection to neuroblastoma, having studied the disease for years and seeing his son diagnosed with it in 2021, emphasized the importance of reducing drug dosages to minimize side effects in pediatric cancer treatment. His experience with his son's treatment has driven his focus on pre-treating tumors to achieve better responses with lower drug dosages.
The gene therapy approach avoids the use of viral vectors, addressing concerns about potential long-term toxicity. Dr. Sirsi sees this nonviral therapy, utilizing microbubbles, as a safer and more effective strategy, especially for pediatric patients.
Beyond neuroblastoma, Dr. Sirsi envisions the potential application of this approach to other cancers and intends to explore its compatibility with various cancer treatments, including radiotherapy and immunotherapy.
The study involved collaboration with researchers from The University of Chicago Pritzker School of Medicine and Dr. Theodore Laetsch from the Children’s Hospital of Philadelphia. The research was supported in part by the National Institutes of Health’s National Cancer Institute and the Pediatric Cancer Foundation. Microbubbles used in the study were provided by Advanced Microbubbles, a company co-founded by Dr. Sirsi, who serves as its Chief Scientific Officer, and Dr. Laetsch, who acts as the company’s pediatric oncology advisor.