Discovery of Small-Molecule Selective mTORC1 Inhibitors via Direct Inhibition of Glucose Transporters

Area of Science:

• Biochemistry
• Cell Biology
• Pharmacology

Background:

• The mechanistic target of rapamycin (mTOR) pathway regulates cellular metabolism and is implicated in various human diseases.
• Rapamycin analogs, while targeting mTORC1, can inhibit both mTORC1 and mTORC2 with chronic use.
• Selective inhibition of mTORC1 is a therapeutic goal for specific conditions.

Purpose of the Study:

• To develop a high-throughput screening method to identify selective mTORC1 inhibitors.
• To characterize a novel chemical scaffold with selective mTORC1 inhibitory properties.
• To elucidate the molecular mechanism underlying the selective inhibition of mTORC1.

Main Methods:

• High-throughput cell-based screening for phosphorylated mTORC1 and mTORC2 substrates (4E-BP1, S6K1, Akt).
• Chemical scaffold characterization for selective mTORC1 inhibition profile.
• Stable isotope labeling of amino acids in cell culture (SILAC) proteomics for target identification.
• Assessment of glucose uptake inhibition.

Main Results:

• A novel chemical scaffold was identified, selectively inhibiting mTORC1.
• Proteomic analysis revealed class I glucose transporters as the primary targets of the compounds.
• The compounds potently inhibited glucose uptake, leading to selective mTORC1 inhibition.
• A potential link between glucose uptake and mTORC1 regulation by an unknown glucose sensor was suggested.

Conclusions:

• A novel chemical scaffold selectively inhibits mTORC1 through targeting glucose transporters.
• This discovery provides a new mechanism for selective mTORC1 inhibition, distinct from traditional rapamycin-based therapies.
• Further research into the glucose sensor mechanism could reveal new therapeutic strategies for metabolic disorders.