January 28, 2005
FURTHER PRECLINICAL PROGRESS IN SALIVARY GLAND GENE TRANSFER
Each year, more than 35,000 Americans receive radiation therapy to treat head and neck cancer. Although the radiation is helpful in thwarting the tumor, it can also inadvertently damage salivary glands, causing a marked reduction in the patient’s salivary flow. For several years, a group of NIDCR scientists has been developing a strategy to efficiently transfer a gene into irradiated salivary glands in hopes of supplementing or fully restoring salivary production in these patients. In their initial animal studies, the scientists transferred genetic material encoding the well-characterized water channel protein, human aquaporin-1, into the salivary glands of rats that had been exposed to radiation four months earlier and restored near normal salivary flow. Follow-up studies in rhesus monkeys, however, led to equivocal results, raising concerns about the clinical potential of aquaporin-1 gene transfer in people. Recently, the NIDCR scientists and their colleagues in China evaluated the human aquaporin-1 gene transfer strategy in another large, well-characterized animal model, the miniature pig. As posted online recently in the journal Molecular Therapy, they found the gene transfer significantly increased salivary secretion without causing significant side effects.