Interferon-beta endogenously produced by intratumoral injection of cationic liposome-encapsulated gene: cytocidal effect on glioma transplanted into nude mouse brain.

The cytocidal effect of endogenously produced human interferon-beta was tested on glioma transplanted into the brain of nude mice by intracranial injection of a cell suspension of human glioma cell line U251-SP. When plasmid pSV2IFN-beta, bearing the human interferon-beta gene, was encapsulated into cationic multilamellar liposomes composed of N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, dilauroyl phosphatidylcholine, and dioleoyl phosphatidylethanolamine in a molar ratio of 1:2:2 and injected intratumorally, human interferon-beta was produced in the tumor. The tumor completely disappeared if the injection was done shortly after the transplantation. Even when the tumor did not disappear, survival of the tumor-bearing nude mice was markedly prolonged. In control experiments made with normal brain having no glioma, interferon-beta was not detected.