Despite the fact that mTORC1 is a known "master regulator" of cellular metabolism and many groups have identified metabolic defects in cells deficient in the TSC1 or TSC2 proteins, how to translate these discoveries into improved therapeutic strategies for TSC is incompletely understood, representing a fundamental knowledge gap. Furthermore, the effects of cellular metabolism can be cell-type and species-dependent, and the vast majority of these studies were done in cells from mice or rats.

Our central hypothesis is that we can utilize patient-derived cells to identify highly effective, well-tolerated metabolically targeted therapeutic strategies for children and adults with TSC. This project is a key step in translating metabolic reprogramming from "bench to bedside" and may lead to completely new, highly feasible therapeutic concepts for TSC, using agents that are already clinically available with very favorable safety profiles.

In Aim 1, we will define how the metabolism of TSC2-deficient patient-derived cells is "reprogrammed" in order to identify metabolic vulnerabilities or "Achilles' heels" that can be used to design novel therapies. This will be done in collaboration with Dr. Clary Clish, who is the Director of the Metabolomic Platform at the Broad Institute of the Massachusetts Institute of Technology and Harvard. In Aim 2, we will test drugs and compounds that target these vulnerabilities on the growth and survival of patient-derived cells in cell culture. We will also perform a drug screen of patient-derived cells to identify new therapeutic agents for TSC that are already Food and Drug Administration-approved, in collaboration with Dr. Caroline Shamu, Director of the Institute for Chemical and Cellular Biology-Longwood at Harvard Medical School. In Aim 3, we will test drugs and compounds that target metabolic vulnerabilities on the growth and survival of patient-derived cells, in mice. We will utilize a novel bioluminescent imaging approach that allows us to detect patient-derived cells in living mice, enhancing our ability to conduct efficient preclinical trials of novel therapeutic strategies.

We expect this project to have high clinical impact by revealing how metabolic reprogramming contributes to cell growth and survival in patient-derived cells, thereby paving the way for targeting these metabolic networks in TSC. We expect this project to define novel and highly feasible therapeutic concepts for TSC, with relevance to all proliferative lesions in TSC that are driven by mTORC1 activation. We speculate that targeting cellular metabolism will provide a more complete and durable response when compared with mTORC1 inhibitors as single agents in TSC. In some patients, mTORC1 inhibitors might not be needed at all; in other patients, metabolically targeted therapies could allow mTORC1 inhibitors to be used at lower doses and/or for shorter durations, with metabolic "maintenance" therapy.