Design, synthesis, and biological screening of a series of 4′-fluoro-benzotriazole-acrylonitrile derivatives as microtubule-destabilising agents (MDAs)

Abstract

Introduction: Colchicine-binding site inhibitors are some of the most interesting ligands belonging to the wider family of microtubule-destabilising agents.

Results: A novel series of 4′-fluoro-substituted ligands (5–13) was synthesised. The antiproliferative activity assays resulted in nM values for the new benzotriazole-acrylonitrile derivatives. Compound 5, the hit compound, showed an evident blockade of HeLa cell cycle in the G2-M phase, but also a pro-apoptotic potential, and an increase of early and late apoptotic cells in HeLa and MCF-7 cell cycle analysis. Confocal microscopy analysis showed a segmented shape and a collapse of the cytoskeleton, as well as a consistent cell shrinkage after administration of 5 at 100 nM. Derivative 5 was also proved to compete with colchicine at colchicine-binding site, lowering its activity against tubulin polymerisation. In addition, co-administration of 5 and doxorubicin in drug-resistant A375 melanoma cell line highlighted a synergic potential in terms of inhibition of cell viability.

Discussion: The 4′-fluoro substitution of benzotriazole-acrylonitrile scaffold brought us a step forward in the optimisation process to obtain compound 5 as promising MDA antiproliferative agent at nanomolar concentration.

Graphical Abstract

Keywords:

• Benzotriazole-acrylonitrile
• antiproliferative compounds
• colchicine-binding site inhibitors
• cell growth inhibition
• molecular docking

Acknowledgments

We would like to acknowledge “Assessorato della Programmazione, Bilancio, Credito e Assetto del territorio” of “Regione Autonoma della Sardegna” (Sardinia, Italy) for the funding support with the grant named “Legge Regionale 7 agosto 2007:CRP1_574, 22/41 del 2017,” grant number RASSR01499. The authors would thank the Italian Ministry for University and Research for the funding named PRIN2020. For the in vitro antiproliferative screening, we thank NCI (National Cancer Institute, Developmental Therapeutics Program, Bethesda, USA; https://dtp.cancer.gov).

Author contributions

Conceptualisation: FR, RI, SP, and AC; formal analysis: FR, SZ, RI, LS, ML, and VB; investigation: FR, RI, SZ, LS, and ML; resources: AC; data curation: FR, RI, SS, SZ, LS, ML, LB, and AC; writing/original draft preparation: FR, RI, and SS; writing/review and editing: all authors; supervision: LB and AC; funding acquisition: LB and AC. All authors have read and agreed to the published version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by “Regione Autonoma della Sardegna” (Sardinia, Italy), by “Legge Regionale 7 agosto 2007:CRP1_574, 22/41 del 2017” [grant number RASSR01499] and by Italian Ministry for University and Research with funding named PRIN2020 [grant number PRIN2020CARTA].