Periodic Reporting for period 1 - inhibiTOR (Exploiting Cellular Metabolism to Develop the Next Generation of mTOR Inhibitors)
Reporting period: 2024-06-01 to 2025-11-30
The mTOR protein is a key regulator of how cells sense nutrients and energy and adapt their growth and metabolism accordingly. When the activity of one of its functional forms, mTORC1, is improperly controlled, it contributes to many major health problems, including cancer, metabolic diseases, and ageing-related conditions. For this reason, mTORC1 has long been considered an important target for drug development. However, current drugs that inhibit mTOR have significant limitations. Some only partially block mTORC1 and are therefore not sufficiently effective, while others inhibit multiple mTOR-related pathways at once, often leading to unwanted side effects. There is thus a clear need for new compounds that more effectively and more selectively inhibit mTORC1. This project builds on the discovery that a naturally occurring molecule can directly inhibit mTORC1 inside cells (Nicastro et al. 2023 Nat Cell Biol, PMID: 37563253), revealing a new way in which metabolism can control this important signalling pathway. Although this natural molecule itself is not suitable for therapeutic use, it provides a valuable starting point for developing improved synthetic compounds. The overall objective of the project was to use this discovery to develop and test new molecules with enhanced potency and a stronger preference for mTORC1 inhibition compared to existing drugs. By combining computational design, chemical synthesis, and biological testing, the project aimed to generate promising candidate compounds for future development. The expected impact of the project is to establish the basis for a new class of mTORC1-targeted inhibitors with potential applications in ageing and disease. These results provide a foundation for further optimization, intellectual property generation, and longer-term translational and commercial exploitation.
During the project, we carried out a structured and iterative workflow to develop and evaluate novel inhibitors targeting mTORC1. The work combined computational analysis, chemical synthesis, and cellular testing, as originally planned. First, computational approaches were used to guide the design of synthetic derivatives based on the structure and properties of the natural mTORC1 inhibitor identified in our previous research. These analyses informed the selection of chemical modifications predicted to improve potency and functional performance. Based on this design strategy, two successive rounds of compound synthesis were performed, with chemical synthesis outsourced to a contract research organization as foreseen. The first round generated initial candidate molecules, which were tested in cellular assays to assess their effects on mTOR signalling and cell viability. Results from this round were used to adjust our strategy and refine compound design for a second synthesis round. The synthesized compounds were evaluated using established cellular assays, including dose–response and time-course analyses, and comparative measurements of mTORC1 and mTORC2 pathway activity using reference inhibitors as controls. This iterative optimization resulted in a marked improvement in compound performance, progressing from compounds active only at high concentrations to second-generation compounds that efficiently inhibit mTORC1 at low nanomolar concentrations. By the end of the project, several novel chemical entities had been identified that show substantially increased potency and a clear preference for mTORC1 inhibition compared to existing compounds. These outcomes demonstrate the technical feasibility of developing a new class of mTORC1-targeted inhibitors and provide a strong experimental basis for further optimization and translational development.
This project delivers results that go beyond the current state of the art in mTOR-targeted drug development by establishing a new inhibitor concept that differs fundamentally from existing approaches. Current mTOR inhibitors either only partially suppress mTORC1 activity or lack sufficient selectivity, often leading to reduced efficacy or adverse effects. In contrast, the compounds developed in this project are based on a novel metabolic inhibition principle and demonstrate strong and preferential inhibition of mTORC1 in cells. A key advance achieved during the action is the substantial increase in inhibitor potency, progressing from near millimolar concentrations required for the endogenous reference molecule and early derivatives to low nanomolar concentrations for optimized second-generation compounds. This level of activity, combined with partial preferential targeting of mTORC1, represents a significant improvement over existing mTOR inhibitor classes and highlights the translational potential of the approach. Beyond potency, the project demonstrates the technical feasibility of using a naturally occurring metabolic inhibitor as a blueprint for the rational design of synthetic compounds with enhanced pharmacological properties. This opens a new direction for targeting mTORC1 that is complementary to, and distinct from, rapalogs and catalytic mTOR inhibitors. To ensure further uptake and success, additional work is required to fully characterize and optimize the most promising compounds, including extended selectivity profiling, assessment of pharmacokinetic properties, and evaluation in more advanced disease-relevant models. These steps will support the identification of a robust lead compound suitable for intellectual property protection and subsequent commercialization. Access to follow-up funding, industrial partnerships, and IPR support will be key enablers for advancing these results toward clinical and market applications. In summary, the project establishes a strong proof of concept for a new class of potent and preferential mTORC1 inhibitors and provides a clear foundation for future translational development beyond the current state of the art.