Background: Triple-negative BC is the most aggressive type of breast cancer and its lack of responsiveness to conventional
therapies requires screening of new chemical entities. Anti-migratory compounds are promising to treat metastatic cancer since they
inhibit one of the main steps of the metastatic cascade. Spirocyclic compounds are non-conventional structures used as building blocks
for the synthesis of biologically active molecules and considered interesting structures in the search for exploration of new targets in
Objective: Here we evaluated the potential of eight synthetic spirocyclohexadienones as cell migration inhibitors.
Methods: The anti-migratory ability of compounds was tested by wound healing and Boyden chamber approaches. Experiments in
tubulin were performed by fluorescence and tubulin polymerization techniques. Finally, compounds were submitted to cell proliferation
inhibition and flow cytometry assays to explore the mechanism by which they inhibit cell migration.
Results: Four compounds inhibited cell migration significantly. Analogs containing the 3,4,5-trimethoxyphenil ring at R1 position were
the most potent and thus selected for additional experiments. Tubulin polymerization and fluorescence assays highlighted a possible
binding of spirocyclohexadienones in colchicine binding site; however, compounds did not affect cell cycle to the same extent as
colchicine. Cell proliferation was affected and, notably, the most potent analogs induced apoptosis of tumor cells, suggesting a different
mechanism by which they inhibit cell migration.
Conclusion: We presented for the first time a series of eight synthetic spirocyclohexadienones with the ability to inhibit TNBC cell
migration. These compounds represent a new category to be explored as anticancer agents.