Resveratrol is a well-known chemopreventive and chemotherapeutic agent. Among all of the resveratrol analogs synthesized, 3,4,5,4′-tetramethoxystilbene (DMU-212) shows high activity and selectivity against various cancer cell types. The objective of this study is to investigate why DMU-212 has higher anti-tumor activity than resveratrol.

The effects of DMU-212 and resveratrol on cell viability, cell cycle, Stat3 activation, and microtubule dynamic were investigated and compared using MTT assay, cell cycle analysis, Western blot, tubulin polymerization assay, respectively, in MDA-MB-435 and MCF-7 human breast cancer cells.

Compared to resveratrol, DMU-212 exerted a significantly higher growth inhibition in both cell lines. Further studies demonstrated that DMU-212 acted via different mechanisms from resveratrol. First, DMU-212 induced predominantly G2/M arrest whereas resveratrol induced G0/G1 arrest in both cell lines. Correlating with these findings, resveratrol induced more dramatic changes in the expression of Cyclin D1 compared to DMU-212. Second, DMU-212 induced apoptosis and reduced the expression of multiple anti-apoptotic proteins more appreciably than resveratrol. Third, while both agents inhibited Stat3 phosphorylation, treatments of DMU-212 but not resveratrol led to a significant increase in tubulin polymerization. The higher sensitivity to DMU-122 in MDA-MB-435 correlated with the more prominent effects seen in these parameters in this cell line, as compared to MCF7.

Compared to resveratrol, the novel stilbene derivative, DMU-212, had higher anti-tumor effects, which are likely owing to its modulation of multiple cellular targets.