Identification of nonsense-mediated decay inhibitors that alter the tumor immune landscape

Area of Science:

• Molecular Biology
• Immunology
• Drug Discovery

Background:

• Cancer immunotherapy is limited by a lack of targetable tumor antigens.
• Nonsense-mediated decay (NMD) is a cellular pathway that degrades RNA from mutated genes, hiding potential neoantigens.
• Identifying NMD regulators is crucial for developing new cancer therapies.

Purpose of the Study:

• To identify key mediators of nonsense-mediated decay (NMD) in human cells.
• To develop a novel small molecule inhibitor targeting NMD.
• To evaluate the efficacy of the inhibitor in enhancing neoantigen presentation for cancer immunotherapy.

Main Methods:

• High-throughput screening using ratiometric transcript analysis to identify NMD mediators.
• Design and synthesis of a novel SMG1 kinase inhibitor, KVS0001.
• In vitro and in vivo studies in human and murine cancer cells to assess NMD inhibition and neoantigen presentation.

Main Results:

• A screen identified disruption of SMG1-mediated UPF1 phosphorylation as a key NMD regulatory mechanism.
• The novel SMG1 inhibitor, KVS0001, was developed, effectively increasing transcript and protein expression from truncating mutations.
• KVS0001 significantly enhanced the presentation of immune-targetable HLA class I-associated peptides on human cancer cells.

Conclusions:

• KVS0001 is a potent NMD inhibitor that can unmask neoantigens by increasing the expression of mutated proteins.
• This drug candidate shows promise for enhancing cancer immunotherapy by improving the visibility of targetable antigens.
• KVS0001 offers new avenues for research into NMD's role in cancer and other diseases.