PROSTVAC, a therapeutic vaccine for treating prostate cancer
The development of restriction enzyme technology in the 1970s was a breakthrough in genetic engineering. For the first time, scientists were able to cut DNA at specific sites and insert sequences with matching ends. However, the technology was limited to insertion at particular sites in the host vector, and the size of the inserted DNA quickly became a limiting factor. The National Cancer Institute’s (NCI) solution is a technology that consists of three specialized bacterial strains and seven plasmids, developed around a genetic system in E. coli that was harnessed into an enabling platform technology, allowing for highly efficient, rapid, and direct manipulation of larger DNA sequences (up to 100kb) than previously enabled by conventional molecular biology methods. This system, called recombineering, has revolutionized genetic engineering techniques, including the modification of genes on bacterial artificial chromosomes (BACs) and the generation of conditional knockout mice.
The research community has enthusiastically received this technology, and over 1,100 nonprofit researchers thus far have received the materials. The technology transfer efforts initially focused on the negotiation of individual Material Transfer Agreements with each recipient. However, growing interest created the need for a simple and streamlined process, leading to deposit of the materials in the NCI’s Preclinical Repository in 2007 and making the NIH Simple Letter Agreement available online. This has greatly expedited transfer of the materials. In addition, the inventors have three issued patents and several applications pending, and the technology has been nonexclusively licensed to 18 commercial entities.
The NCI team continues to develop the technology, making improvements to the initial bacterial strains that have resulted in a “second generation” set. The laboratory continues to use the technology in research on gene regulation and initiation of transcription and translation, and it has been the subject of over 125 publications by both the inventors and outside investigators. Other diverse uses of the technology include stem cell research, genetic studies in model organisms, creation of research tools such as transgenic mice and specialized imaging vectors, and high-throughput screening.