BetaGene, Inc. is seeking support for development of its proprietary cell- based insulin replacement therapy for type 1 diabetes. Islet transplantation is plagued by the dual problems of limiting sources of tissue and the difficulties inherent in protecting transplanted tissue from attack by the immune system. To combat these problems, BetaGene has successfully engineered rodent neuroendocrine cell lines that mimic normal islet beta- cells, both in terms of the amount of insulin that they secrete and their responses to physiological signals such as glucose. In a collaborative effort BetaGene has demonstrated the feasibility of transplanting encapsulated cell lines for long-term treatment of experimental growth hormone and insulin deficiency in rodent models. The company has also developed strategies for protecting insulin secreting cells from immunological attack, particularly the damaging effects of inflammatory cytokines. While proof- of-principal studies indicate that the engineered rodent cell lines can lower blood glucose in an allograft setting, it is unlikely that such cells will be useful as xenografts in humans. Based on this, BetaGene is now focused on development of human cell lines that can be used for allograft therapy of human diabetes. The approach taken in this proposal is to engineer human neuroendocrine cell lines of non-beta-cell origin for this purpose, based on encouraging preliminary data showing complete processing of expressed proinsulin in such cells. Tie specific aims of the proposal are: 1) To continue engineering of a candidate human lung neuroendocrine cell line for secretion of therapeutically relevant amounts of correctly processed insulin; 2) To evaluate other candidate human neuroendocrine cell lines derived from tissues other than lung (e.g., neuroblastoma, pancreatic carcinoma) as vehicles for regulated insulin delivery, including screening for capacity to process proinsulin and expression of ion channels thought to be involved in regulation of insulin secretion, and 3) To engineer the best candidate human cell lines for glucose stimulated insulin secretion by methods developed at BetaGene, and to test these cells for their capacity to secrete insulin in a stable fashion in vitro and in vivo. PROPOSED COMMERCIAL APPLICATION: TYPE l diabetes afflicts approximately l million individuals in the U.S., and many more millions world-wide. The incidence of new cases of the disease in this country is approximately 30,000/year and rising. The cost of treating all forms of diabetes in the U.S. has been estimated at $100 billion/year. Insulin injection therapy is an antiquated approach for a disease of this magnitude, and the arrive of new therapeutic modalities such as that proposed in this application will like penetrated the market rapidly if proven to be safe and effective.
