Gatorbulin-1, a distinct cyclodepsipeptide chemotype, targets a seventh tubulin pharmacological site

Area of Science:

• Biochemistry
• Pharmacology
• Natural Product Chemistry

Background:

• Tubulin-targeted chemotherapy is a cornerstone in treating various cancers.
• Existing drugs target six known binding sites on α/β-tubulin, affecting microtubule dynamics.
• Novel mechanisms for modulating tubulin are crucial for advancing antitumoral therapies.

Purpose of the Study:

• To discover and characterize novel tubulin-binding agents.
• To identify a new binding site on tubulin for therapeutic intervention.
• To elucidate the chemical structure and mechanism of action of a novel cyclodepsipeptide, gatorbulin-1 (GB1).

Main Methods:

• Bioactivity-guided isolation of natural products from marine cyanobacteria.
• Multinuclei NMR spectroscopy for structure determination of GB1.
• Total synthesis to validate chemical structure and biological activity.
• Isogenic cancer cell line screening and cellular profiling.
• In vitro biochemical assays and crystallographic studies of the tubulin-GB1 complex.

Main Results:

• Discovery of gatorbulin-1 (GB1), a novel microtubule-destabilizing cyclodepsipeptide.
• Identification of a previously unknown seventh binding site at the tubulin intradimer interface for GB1.
• Elucidation of GB1's unique chemotype, featuring a modified pentapeptide and a critical hydroxamate group.
• Confirmation of GB1's antitumoral potential through pharmacological profiling and mechanistic studies.

Conclusions:

• Gatorbulin-1 (GB1) represents a novel class of tubulin-binding agents with a unique mechanism of action.
• The discovery of a new binding site offers opportunities for developing next-generation cancer chemotherapeutics.
• GB1's distinct chemical structure and mechanism provide a promising foundation for future drug development against malignancies.