A Novel Resveratrol Based Tubulin Inhibitor Induces Mitotic Arrest and Activates Apoptosis in Cancer Cells

Resveratrol is one of the most widely studied bioactive plant polyphenols which possesses anticancer properties. Previously we have reported synthesis, characterization and identification of a novel resveratrol analog, SS28. In the present study, we show that SS28 induced cytotoxicity in several cancer cell lines ex vivo with an IC50 value of 3–5 μM. Mechanistic evaluation of effect of SS28 in non-small cell lung cancer cell line (A549) and T-cell leukemic cell line (CEM) showed that it inhibited Tubulin polymerization during cell division to cause cell cycle arrest at G2/M phase of the cell cycle at 12–18 h time period. Immunofluorescence studies confirmed the mitotic arrest upon treatment with SS28. Besides, we show that SS28 binds to Tubulin with a dissociation constant of 0.414 ± 0.11 μM. Further, SS28 treatment resulted in loss of mitochondrial membrane potential, activation of Caspase 9 and Caspase 3, leading to PARP-1 cleavage and finally cell death via intrinsic pathway of apoptosis. Importantly, treatment with SS28 resulted in regression of tumor in mice. Hence, our study reveals the antiproliferative activity of SS28 by disrupting microtubule dynamics by binding to its cellular target Tubulin and its potential to be developed as an anticancer molecule.

Protocol publication

[…] 3D structure of SS28 was generated in Discovery studio package using in-built dreiding-like force field (Discovery Studio 4.0. Accelrys, USA). 3D crystal structure of α, β-Tubulin bound with colchicine was retrieved from protein databank (PDB ID: 3UT5, www.rcsb.org/pdb). Molecular docking studies were carried out with Autodock4.2 program. Briefly, SS28 was docked in colchicine binding site keeping the grid centres 9.45, 56.62 and 87.95 for X, Y and Z respectively (npts = 50 for X, Y and Z, spacing = 0.375). Rigid docking was carried out using Lamarckian genetic algorithm (GA run was kept 20 with medium search parameter). Best pose was selected according to lower binding energy and presented in the final image using Pymol. […]