A molecular dynamics investigation into the mechanisms of alectinib resistance of three ALK mutants

Area of Science:

• Oncology
• Molecular Biology
• Computational Chemistry

Background:

• Alectinib is a potent anaplastic lymphoma kinase (ALK) inhibitor for ALK-positive non-small cell lung cancer (NSCLC).
• Acquired resistance mutations in ALK limit alectinib's long-term therapeutic efficacy.
• The precise molecular mechanisms underlying alectinib resistance remain unclear.

Purpose of the Study:

• To elucidate the molecular mechanisms of alectinib resistance caused by specific ALK mutations (I1171N, V1180L, L1198F).
• To identify structural motifs responsible for reduced alectinib binding affinity in resistant ALK variants.

Main Methods:

• Utilized molecular dynamics (MD) simulations to observe dynamic changes.
• Employed molecular mechanics generalized Born surface area (MM-GBSA) calculations to quantify binding affinity changes.
• Analyzed conformational alterations in the ALK active site and inhibitor binding pocket.

Main Results:

• Mutations I1171N, V1180L, and L1198F induce alectinib dislocation and conformational changes at the binding site.
• The ligand binding entrance and hinge region are significantly affected, leading to binding affinity loss.
• A specific 'key and lock mechanism' involving alectinib's ethyl group and the ALK hinge region cavity is identified as a key resistance driver.

Conclusions:

• Specific ALK mutations mechanistically impair alectinib binding through structural and interactional changes.
• Understanding these resistance mechanisms is crucial for developing next-generation ALK inhibitors.
• This study provides a foundation for rationally designing novel drugs to overcome acquired alectinib resistance in NSCLC.